Phase II trial launched for Nilotinib

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Big news today from Georgetown University with the announcement that they will be starting a phase II trial for the cancer drug Nilotinib.

Click here to read the press release.

In this post we will discuss what has happened thus far and what the new trial will involve.


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Georgetown University (Washington DC). Source: Wallpapercave

In October 2015, researchers from Georgetown University announced the results of a small clinical trial at the Society for Neuroscience conference in Chicago.

It is no understatement to say that the results of that study got the Parkinson’s community very excited.

The study (see the abstract here) was a small clinical trial (12 subjects; 6 month study) that was aiming to determine the safety and efficacy of a cancer drug, Nilotinib (Tasigna® by Novartis), in advanced Parkinson’s Disease and Lewy body dementia patients. In addition to checking the safety of the drug, the researchers also tested cognition, motor skills and non-motor function in these patients and found 10 of the 12 patients reported meaningful clinical improvements.

In their presentation at the conference in Chicago, the investigators reported that one individual who had been confined to a wheelchair was able to walk again; while three others who could not talk before the study began were able to hold conversations. They suggested that participants who were still in the early stages of the disease responded best, as did those who had been diagnosed with Lewy body dementia.

The study involved the cancer drug Nilotinib.

What is Nilotinib?

Nilotinib (pronounced ‘nil-ot-in-ib’ and also known by its brand name Tasigna) is a small-molecule tyrosine kinase inhibitor, that has been approved for the treatment of imatinib-resistant chronic myelogenous leukemia (CML). That is to say, it is a drug that can be used to treat a type of leukemia when the other drugs have failed. It was approved for this treating cancer by the FDA in 2007.

How does Nilotinib work?

The researchers behind the study suggest that Nilotinib works by turning on autophagy – the “garbage disposal machinery” inside each neuron. Autophagy is a process that clears waste and toxic proteins from inside cells, preventing them from accumulating and possibly causing the death of the cell.

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The process of autophagy. Source: Wormbook

Waste material inside a cell is collected in membranes that form sacs (called vesicles). These vesicles then bind to another sac (called a lysosome) which contains enzymes that will breakdown and degrade the waste material.

The investigators believe that nilotinib may be helping in Parkinson’s disease, by clearing away the waste building up in cells – allowing the remaining cells to function more efficiently.

This is great, so what happened in 2016?

That’s a great question.

First, the results of the study being published (Click here to read those results). Second, the U.S. Food and Drug Administration (FDA) reviewed Georgetown’s investigational new drug application (IND) for nilotinib in Parkinson’s disease, and they informed the Georgetown University investigators that a new clinical trial could proceed.

But after that, there were whispers of issues and problems behind the scenes.

Back in August we wrote a post about the Phase II trial being delayed due to disagreements about the design of the study (Read that post by clicking here). Two separate research groups emerged from those disagreements (Georgetown University researchers themselves and a consortium including the Michael J Fox Foundation). Click here for the STAT website article outlining the background of the issues, and click here for the Michael J Fox Foundation statement regarding the situation. The Georgetown University team have a lot of leverage in this situation as they control the patent side of things (Click here to see the patent).

We are not sure what has happened since August, but the Georgetown University team has now announced that they are going to go ahead with a phase II trial to look at safety and efficacy of nilotinib in Parkinson’s disease.

What do we know about the new trial?

At the moment the details are basic:

The design of the study involves two parts:

In the first part of the study, one third of the participants receiving a low dose (150mg) of nilotinib, another third receiving a higher dose (300mg) of nilotinib and the final third will receive a placebo drug (a drug that has no bioactive effect to act as a control against the other two groups). The outcomes will be assessed clinically at six and 12 months by investigators who are blind to the treatment of each subject. These results will be compared to clinical assessments made at the start of the trial. (We are not sure if brain imaging – for example, a DATscan – will be included in the assessment, but it would be useful)

In the second part of the study, there will be a one-year open-label extension trial, in which all participants will be randomized given either the low dose (150mg) or high dose (300mg) of nilotinib. This extension is planned to start upon the completion of the first part (the placebo-controlled trial) to evaluate nilotinib’s long-term effects. (We are a little confused by this study design with regards to efficacy, but determining the safety issues of using nilotinib long term is important to establish).

We are not clear on how many subjects will be involved in the study or what the criteria for eligibility will be. All we can suggest is that if you are interested in finding out more about this new study, you can sign up here to receive more information as it becomes available.

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Summing up, this is welcomed news for the Parkinson’s community as we will finally be able to determine if nilotinib is having positive effects in Parkinson’s disease. There have been some concerns raised that the effects of the drug in the first clinical study may have been the result of removing additional Parkinsonian treatments during the study (Click here for more on this). This new study will hopefully help to clarify things.

And fingers crossed provide us with a useful new treatment for Parkinson’s disease.


The banner for today’s post was sourced from William-Jon

New kiwi research in Parkinson’s disease

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I really didn’t expect to be writing about Parkinson’s research being conducted in New Zealand again so quickly, but yesterday a new study was published which has a few people excited.

It presents evidence of how the disease may be spreading… using cells collected from people with Parkinson’s disease.

In today’s post we will review the study and discuss what it means for Parkinson’s disease.


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The South Island of NZ from orbit. Source: Sciencenews

We may have mentioned the protein Alpha synuclein once or twice on this blog.

For anyone familiar with the biology of Parkinson’s disease, alpha synuclein is a major player. It is either public enermy no.1 in the underlying pathology of this condition or else it is the ultimate ‘fall guy’, left standing in the crime scene holding the bloody knife.

Remind me, what is alpha synuclein?

Alpha synuclein is an extremely abundant protein in our brains – making up about 1% of all the proteins floating around in each neuron (one of the main types of cell in the brain).

In healthy brain cells, normal alpha synuclein is typically found just inside the surface of the membrane surrounding the cell body and in the tips of the branches extending from the cell (in structures called presynaptic terminals which are critical to passing messages between neurons).

And why is alpha synuclein important in Parkinson’s disease?

Genetic mutations account for 10-20% of the cases in Parkinson’s disease.

Five mutations in the alpha-synuclein gene have been identified which are associated with increased risk of Parkinson’s disease (A53T, A30P, E46K, H50Q, and G51D – these are coordinates for locations on the alpha synuclein gene). Rare duplication or triplication of the gene have also been associated with  Parkinson’s disease.

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The structure of alpha synuclein protein – blue squares are mutations. Source: Mdpi

So genetically, alpha synuclein is associated with Parkinson’s disease. But it is also involved at the protein level.

In brains of many people with Parkinson’s disease, there are circular clumps of alpha synuclein (and other proteins) that collect inside cells. These clumps are called Lewy bodies. They are particularly abundant in areas of the brain that have suffered cell loss.

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A lewy body (brown with a black arrow) inside a cell. Source: Cure Dementia

No one has ever seen the process of Lewy body formation, so all we can do is speculate about how these aggregates develop. Currently there is a lot of evidence supporting the idea that alpha synuclein can be passed between cells. Once inside the new cell, the alpha synuclein helps to seed the formation of new Lewy bodies, and this is how the disease is believed to progress.

Mechanism of syunuclein propagation and fibrillization

The passing of alpha synuclein between brain cells. Source: Nature

Exactly how alpha synuclein is being passed between cells is the topic of much research at the moment. There are many theories and some results implicating methods such as direct penetration, or via a particular receptor. Perhaps even by a small package called an exosome being passed between cells (see image above).

How this occurs in the Parkinson’s disease brain, however, is unknown.

And this (almost) brings us to the kiwi scientists.

Last years, a group of Swiss scientists demonstrated that alpha synuclein could be passed between cells via ‘nanotubes’ – tiny tubes connecting between cells. The outlined their observations and results in this article:

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Title: Tunneling nanotubes spread fibrillar α-synuclein by intercellular trafficking of lysosomes.
Authors: Abounit S, Bousset L, Loria F, Zhu S, de Chaumont F, Pieri L, Olivo-Marin JC, Melki R, Zurzolo C.
Journal: EMBO J. 2016 Oct 4;35(19):2120-2138.
PMID: 27550960

The researchers who conducted this study were interested in tunneling nanotubes.

Yes, I know, ‘What are tunneling nanotubes?’

Tunneling nanotubes (also known as Membrane nanotubes or cytoneme are long protrusions extending from one cell membrane to another, allowing the two cells to share their contents. They can extend for long distances, sometimes over 100 μm – 0.1mm, but that’s a long way in the world of cells!

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Tunneling nanotubes (arrows). Source: Wikipedia (and PLOSONE)

Previous studies had demonstrated that tunneling nanotubes can pass different infectious agents (HIV for example – click here to read more on this), supporting the idea that these structures could be a general conduit by certain diseases could be spreading.

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A tunneling nanotube between two cells. Source: Pasteur

In their study the Swiss researchers found that alpha synuclein could be transferred between brain cells (grown in culture) via tunneling nanotubes. In addition, following that process of transfer, the alpha synuclein was able to induce the aggregation (or clumping) of the alpha synuclein in recipient cells.

A particularly interesting finding was that alpha synuclein appeared to encourage the appearance of tunneling nanotubes (there were more tunneling nanotubes apparent when cells produced more alpha synuclein). And the alpha synuclein that was being transferred was being passed on in ‘lysosomal vesicles’ – these are the rubbish bags of the cell (lysosomal vesicles are used to take proteins away for degradation).

Paints a rather insidious picture of the ‘ultimate fall guy’ huh!

And that image was made worse by the results published by the kiwis last night:

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Title: α-synuclein transfer through tunneling nanotubes occurs in SH-SY5Y cells and primary brain pericytes from Parkinson’s disease patients
Authors: Dieriks BV, Park TI, Fourie C, Faull RL, Dragunow M, Curtis MA.
Journal: Scientific Reports, 7, Article number: 42984
PMID: 28230073                    (This article is OPEN ACCESS if you would like to read it)

In their study, the New Zealand scientists extended the Swiss research by looking at cells collected from people with Parkinson’s disease. The researchers took human brain pericytes, which were derived from the postmortem brains of people who died with Parkinson’s disease.

And before you ask: pericytes are cells that wrap around the cells lining small blood vessels. They are important to the development of new blood vessels and maintaining the structural integrity of microvasculature.

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A pericyte (blue) hugging a blood vessel (red). Source: Xvivo

Pericytes contain alpha synuclein precipitates like those seen in neurons, and the kiwi scientists demonstrated that pericytes too can transfer alpha synuclein via tunneling nanotubes to neighbouring cells – representing a non-neuronal method of transport.

They also found that the transfer through the tunneling nanotubes can be very rapid – within 30 seconds – and the transferred alpha synuclein can hang around for more than 72 hours, suggesting that it is difficult for the receiving cell to dispose of. The researchers did note that the transfer through tunneling nanotubes occurred only in small subset of cells, but that this could explain the slow progression of Parkinson’s disease over time.

What does it all mean?

In order for us to truly tackle Parkinson’s disease and bring it under control, we need to know how this slowly progressing neurodegenerative condition is spreading. Some researchers in New Zealand have provided evidence involving cells collected from people with Parkinson’s disease that indicates one method by which the disease could be passed from one cell to another.

Tiny tunnels between cells, allowing material to be shared, could explain how the disease slowly progresses. The scientists observed the Parkinson’s associated protein alpha synuclein being passed between cells and then hanging around for more than a few days.

This method of transfer was made more interesting because the New Zealand researchers reported that non-neuronal cells (Pericytes, collected from people with Parkinson’s disease) could also form tunneling nanotubes. This observation raises questions as to what role non-neuronal cells could be playing in Parkinson’s disease.

This line of questions will obviously be followed up in future research, as will efforts to determine if tunneling nanotubes are actually present in the human brain or simply biological oddities present only in the culture dish. Demonstrating nanotubes in the brain will be difficult, but it would provide us with solid evidence that this method of disease transfer could be a bonafide cause of disease spread.

We watch with interest for further work in this area.


FULL DISCLOSURE: The author of this blog is a kiwi… and proud of it. He is familiar with the researchers who have conducted this research, but has had no communication with them regarding the publishing of this post. He simply thought that the results of their study would be of interest to the Parkinson’s community.


The banner for today’s post was sourced from Pinterest

How pigs are helping with Parkinson’s disease

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A biotech company in Australasia got the green light for the next round in a clinical trial two weeks ago.

Their product: tiny cylinders filled with pig cells.

Their mission: to treat Parkinson’s disease with the regenerative healing properties of naturally occurring cells.

In today’s post we will look at what the company is doing and what will happen next.


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Source: ProactiveInvestors

We have been contacted by several readers asking for a post on the press release last week regarding the clinical trial being conducted by Living Cell Technologies Limited (LCT).

Two weeks ago LCT received approval to commence the treatment of 6 patients in their third group of subjects in a Phase IIb clinical trial of NTCELL® for Parkinson’s disease, at Auckland City Hospital in New Zealand (Click here for the press release).

The company completed treatment of all six patients in ‘group 2’ of the Phase IIb clinical trial of NTCELL for Parkinson’s disease at the end of 2016. Four patients in the trial had 40 NTCELL microcapsules implanted into the putamen on each side of their brain, and two patients had sham surgery with no NTCELL implanted. They now have approval to repeat this in a third group of subjects.

What do we know about the company?

Founded in 1999, the initial goal of the company was to develop regenerative cell therapies. This goal was to be achieved by transplanting cells from Auckland Island pigs into humans.

The first disease considered for this approach was type 1 diabetes, which is now being pursued by a joint venture company in the US while LCT focuses its attention on Parkinson’s disease.

What are NTCELL microcapsules?

NTCELL is an a tiny capsule, that contains choroid plexus cells (taken from pigs). The capsule is made of a semi permeable membrane that allows all of the good chemicals and nutrients (that the cells are producing) to escape into the surrounding environment. At the same time it doesn’t let the cells escape, nor does it allow negative elements into the capsule. In addition, the bodies immune system can’t get at the foreign cells and remove them due to the membrane surrounding the capsule.

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An example of encapsulated cells. Source: LEN

These capsules can be transplanted into the brain of people with neurodegenerative conditions, providing the brains of those individuals with the benefits of supportive chemicals and nutrients.

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A brain scan of NTCELL capsules transplanted in the human brain. Source: LCT

Interesting, but what are choroid plexus cells?

Believe it or not, there are some empty spaces inside your brain. Spaces where there are no brain cells (neurons).

These spaces are called the ‘ventricles‘.

In the human brain there are 4 basic divisions of the ventricles as you can see in the image below (the ventricles are the yellow space):

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The ventricles and choroid Plexus in the human brain (red coloured regions). Source: PhysRev

The ventricles are filled up with a solution called cerebrospinal fluid. Cerebrospinal fluid is very similar to the liquid portion of blood (or plasma – if you remove the cells from blood, it’s called plasma), except that cerebrospinal fluid is nearly devoid of protein. It is actually made from plasma, but it only contains 0.3% of plasma proteins and about 2/3 of the glucose of blood.

The choroid plexus cells are one of the primary sources of production for the cerebrospinal fluid. That production is actually great – total volume of cerebrospinal fluid in the the average human being turns over almost 4 times per day. Choroid plexus cells can be found in all 4 divisions of the ventricular system (the choroid plexus cells are indicated with red/brown colouring in the image above).

And, um… why pigs?

The choroid plexus cells are sourced from a unique herd of pigs that have been designated pathogen-free. They were originally sourced from the remote sub-Antarctic Auckland Islands, where they have been running around in isolation since 1807.

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The not-so-tropical Auckland Islands, south of NZ. Source: Sciblogs

That isolation has made them ‘pathogen free’ – basically there is a reduced likelihood of endogenous infectious agents (eg. porine (pig) retrovirus (or PERVs)) in the cells – which is a good thing when you are planning to stick something in the brain.

What research has been done on NTCELL?

Firstly, regarding the capsules, the company published this report in 2009:

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Title: Encapsulated living choroid plexus cells: potential long-term treatments for central nervous system disease and trauma.
Authors: Skinner SJ, Geaney MS, Lin H, Muzina M, Anal AK, Elliott RB, Tan PL.
Journal: J Neural Eng. 2009 Dec;6(6):065001.
PMID: 19850973

In this study, the company looked at the utility of the capsules in rodent brains. One important aspect that they wanted to address was how well the cells survive inside the capsules when placed in the brain. They found that the capsules effectively protected the cells from the host immune system, and they survived for the length of the 6 months study without causing any adverse effects.

The capsules were retrieved from the brains of the rats at the end of the study and the viability of cells was analysed. The researchers found that there was no difference in the production of nutrients from the cells in the capsules at 4 months post implantation, but they did see a decrease of 33% at 6 months. In addition, the number of cells decreased to approximately 40% of the pre-implantation values at 6 months.

We are unsure whether the capsules have been altered for the clinical trial.

The researchers followed this research up in 2013 by publishing this paper:

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Title: Recovery of neurological functions in non-human primate model of Parkinson’s disease bytransplantation of encapsulated neonatal porcine choroid plexus cells.
Authors: Luo XM, Lin H, Wang W, Geaney MS, Law L, Wynyard S, Shaikh SB, Waldvogel H, Faull RL, Elliott RB, Skinner SJ, Lee JE, Tan PL.
Journal: J Parkinsons Dis. 2013 Jan 1;3(3):275-91. doi: 10.3233/JPD-130214.
PMID: 24002224       (This article is OPEN ACCESS if you would like to read it)

The researchers wanted to test the capsules in non-human pre-clinical trials. For this purpose they induced Parkinson’s disease in 15 monkeys using the neurotoxin MPTP, waited 10 weeks and then implanted their capsules. Six monkeys were implanted with the NTCELL capsules, 6 were implanted with empty capsules, and 3 received no capsules. The animals were then tested out to 24 weeks post implantation.

The behavioural response was dramatic. Most of the primates with the NTCELL capsules demonstrated positive behavioural benefits by 2 weeks post implantation (becoming statistically significant by 4 weeks), while the controls and empty capsule groups exhibited no behavioural recovery at all across the entire 24 weeks.

In addition to behavioural benefits, the investigators found significantly more dopamine neurons in the brains of the monkeys implanted with the NTCELL capsules when compared to the controls.

These findings were used by the company to justify moving towards clinical trials in humans.

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Source: Healthline

And what do we know about the clinical trial for Parkinson’s disease?

A Phase I/IIa NTCELL clinical trial for the treatment of Parkinson’s disease was completed in June 2015. It was an open label investigation of the safety and clinical effect of NTCELL in 4 people who had been diagnosed with Parkinson’s disease for at least five years.

The trial “met the primary endpoint of safety” and “reversed progression of the disease two years after implant” (as measured by the Unified Parkinson’s Disease Rating Scale (UPDRS)). The NTCELL implantation was well tolerated, with “no adverse events considered to be related to NTCELL”. The results of the trial have not been published, but the press release can be found here.

The results from that trial were used to justify and design a larger Phase IIb trial.

What does Phase IIb mean?

Phase II studies, which are designed to address clinical efficacy and biological activity, can be divided into IIA or IIB, and while there is no stated definition for these labels it is generally agreed that:

  • Phase IIA studies are usually pilot studies designed to demonstrate clinical efficacy or biological activity (‘proof of concept’ studies);
  • Phase IIB studies look to find the optimum dose at which the drug shows biological activity with minimal side-effects (‘definite dose-finding’ studies) – (Source: Wikipedia).

The goal of this Phase IIb LCT clinical study is to “confirm the most effective dose of NTCELL, define any placebo component of the response and further identify the initial target Parkinson’s disease patient sub group”.

A total of 18 patients under 65 years old are taking part in the trial being conducted at Auckland Hospital and Mercy Ascot Hospital in New Zealand. The company will have to wait 26 weeks until after the last patient is implanted to know whether it has been successful in meeting regulator’s conditions on quality, safety, and efficacy. At the 26 weeks mark, the subjects that received the placebo (empty capsules) will be given the NTCELL capsules.

If the current Phase IIb trial is successful, Living Cell Technologies Limited will be looking to “apply for provisional consent to treat paying patients in New Zealand and launch NTCELL® as the first disease modifying treatment for Parkinson’s disease, in 2017” (Source: Ltcglobal). We will wait to see the results of the current study before passing judgement on whether this situation is likely, though it does seem premature given that by the end of the phase IIb trial only 20 people with Parkinson’s disease will have received the NTCELL treatment. A larger phase III trial may be required. Alternatively, if the results of the current trial are truly spectacular, the company may be able to propose a Phase IV style of trial (also called a ‘post-marketing surveillance’ trial) which would allow them to market their product, but they would be required to maintain a strict program of safety surveillance and ongoing technical analysis of the treatment.

Are other companies trying to do something similar?

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Source: NSgene

Another company, NSgene (in Denmark) has a similar sort of experimental product called NsG0301 which is encapsulated human cells that express the neuroprotective protein, GDNF. NsG0301 is still in preclinical testing however, with the Michael J Fox Foundation helping the company to get the clinical trials started.

Sounds very interesting, but what does it all mean?

So in summary, the biotech company LCT have been given permission to continue with their phase II clinical trial which involves placing tiny capsules which contain cells that release beneficial nutrients into the brains of people with Parkinson’s disease. The company will be blind to which individuals are receiving the capsules with cells in them or empty capsules. They should know later in the year if the trials is successful.

One positive feature of this idea is that immune-suppressant treatments are not required as they are with other forms of transplantation therapies. This means that the patient doesn’t need to take medication which stops the immune system from attacking the foreign cells, because the cells are protected by the capsule membrane. Such medication can leave subjects with reduced immune system responses to illness and thus vulnerable.

Having said that, we are a little concerned that the NTCELL product has not been tested thoroughly enough in Parkinson’s disease for the company to be proposing it for commercial use later this year. For example, the phase I open label results could easily be the result of the placebo effect in practise (as all 4 participants knew they were receiving the capsules. This issue could be resolved with DATscan brain imaging of the first 4 subjects (in the phase I trial).

In addition, we would be interested to know how long the cells inside the capsules keep producing cerebrospinal fluid and other beneficial nutrients once inside the human brain. The rodent study (reviewed above) suggested reductions in production from the cells after just 6 months.

While the NTCELL capsules have been tested in many different models of neurological conditions (see the LCT’s publication page for more on this), the company suffered a set back in 2014 when they retracted one of their key pieces of research which demonstrated the use of NTCELL in a rodent model of Parkinson’s disease (Click here for more on this). The study in question was conducted by LCT between 2007 – 2009, and the results were published in The Journal of Regenerative Medicine in 2011. The study was retracted, however, because “the efficacy conclusions in the publication cannot be confirmed”.

To be fair, the company requested the retraction themselves – which is to their credit – and as a precautionary measure LCT placed a hold on any further patient recruitment in their Phase I/IIa clinical study that was underway at the time. But with this study retracted, the published preclinical research for NTCELL in Parkinson’s disease is largely limited to the primate study reviewed above (we are happy to be corrected on this).

We will be intrigued to see the results of the phase II trial, and (if all goes well) whether the New Zealand regulators will be happy for the product to be made commercially available. Depending on the results, they may request further studies. It will definitely be interesting to follow up long-term the 20 subjects who will have received the NTCELL product by that time.

We watch and wait.


UPDATE FROM 1st MAY 2017:

Today Living Cell Technologies Limited posted the following press release:

Treatment completed for all patients in Parkinson’s trial

Living Cell Technologies Limited has completed treatment of all six patients in the third and final group of patients in the Phase IIb clinical trial of NTCELL® for Parkinson’s disease, at Auckland City Hospital.

Four patients had 120 NTCELL microcapsules implanted into the putamen on each side of their brain, and two patients had sham surgery with no NTCELL implanted. To date there are no safety issues in any of the six patients.

The company is blind to the results until 26 weeks after the completion of group 3 of the trial. The results will then be analysed in accordance with the statistical plan and the conclusions announced. This is anticipated to occur in November 2017. Thereafter the patients who received the placebo will receive the optimal treatment.

The Phase IIb trial aims to confirm the most effective dose of NTCELL, define any placebo component of the response and further identify the initial target Parkinson’s disease patient sub group. Providing the trial is successful, the company will apply for provisional consent in Q4 2017 with a view to treating paying patients in New Zealand in 2018.

“The completion of treatment for the patients in group 3 brings us a step closer to our goals of obtaining provisional consent and launching NTCELL as the first disease modifying treatment for Parkinson’s disease,” says Dr Ken Taylor, CEO of Living Cell Technologies.


FULL DISCLOSURE: Living Cell Technologies Limited (LCT) is an Australasian biotechnology company that is publicly listed on the ASX and NSgene is a privately owned company. Under no circumstances should investment decisions be made based on the information provided here. In addition, SoPD has no financial or beneficial connection to either company. We have not been approached/contacted by either company to produce this post. We are simply presenting this information here following requests from our readers and because we thought the science of what the company is doing might be of interest to other readers. The author of this blog is associated with an individual contracted by LCT, but that individual did not request nor was not made aware of this post before publication. 


The banner for today’s post was sourced from the Planner

Confirmation about that gut feeling?

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Very interesting results published last week regarding the bacteria in the intestinal system of people with Parkinson’s disease.

This is an important piece of research because the gut is increasingly being seen as one of the potential start sites for Parkinson’s disease.

In today’s post we will review the results and discuss what they mean.


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Bacteria in the gut. Source: Huffington Post

Before you go to bed tonight, contemplate this:

The human gut hosts tens of trillions of microorganisms, including at least 1000 species of bacteria (which is a guess-timate as we are not really sure how many species there are).

And whenever you feel like you are all alone, know that you are not.

You are never alone: tens of trillions of microorganisms are with you!

And there is sooooooo many of these microorganisms, that they can make up as much as 2 kg of your total weight.

What do the microorganisms do?

Ours bodies are made up of microbiota – that is,  collections of microbes or microorganisms inhabiting particular environments (or region of our body) and creating “mini-ecosystems”. And whether you like this idea or not, you need them.

The microorganisms in the human gut, for example, perform all manner of tasks for you to make your life easier. From helping to break down food, to aiding with the production of some vitamins (in particular B and K).

That’s great, but what does the bacteria in our gut have to do with Parkinson’s disease?

People with Parkinson’s disease quite often have issues associated with the gastrointestinal tract (or the gut), such as constipation for example. Some people believe that some of these gut related symptoms may actually pre-date a diagnosis of Parkinson’s disease, which has led many researchers to speculate as to whether the gut could be a starting point for the condition.

We have previously discussed the gut and Parkinson’s disease in several posts (click here, here and here to read them).

Today we re-address this topic because a group of scientists from the USA have determined that the populations of bacteria in the guts of people with Parkinson’s disease are different to those of healthy individuals.

Sounds interesting. What exactly is the difference?

Well, before we discuss that, we need a little bit of background.

In 2015, a group of scientists from Finland, published this research paper:

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Title: Gut microbiota are related to Parkinson’s disease and clinical phenotype.
Authors: Scheperjans F, Aho V, Pereira PA, Koskinen K, Paulin L, Pekkonen E, Haapaniemi E, Kaakkola S, Eerola-Rautio J, Pohja M, Kinnunen E, Murros K, Auvinen P.
Journal: Mov Disord. 2015 Mar;30(3):350-8.
PMID: 25476529

In this study the researchers compared the fecal microbiomes of 72 people with Parkinson’s disease and 72 control subjects by sequencing the V1-V3 regions of the bacterial 16S ribosomal RNA gene.

Hang on a minute. What does… any of that mean?

Yeah. Ok, that was a bit technical.

The microbiome refers to the genetics of the microorganisms – that is their genomes (or DNA). When researchers want to look at the microbiome of your gut, they do so by collecting fecal samples (delightful job, huh?).

Interesting facts: Fresh feces is made up of approx. 75% water. Of the remaining solid fraction, 84–93% is organic solids. These organic solids consist of: 25–55% gut bacterial matter, 2–25% protein, 25% carbohydrates, and 2–15% fat (Source: Wikipedia).

Still with me?

After collecting the fecal samples, researchers will extract the DNA from the gut bacterial material, which they can then analyse.

And what are the V1-V3 regions of the bacterial 16S ribosomal RNA gene?

The 16S ribosomal RNA gene is universal in bacteria – it is present in all of their genomes/DNA. The genetic sequence of this particular gene is approximately 1,550 base pairs long, and contains regions that are highly conserved (that is they are shared between species) and highly variable (very different between species).

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The 16S ribosomal RNA gene. Source: Alimetrics

The gene contains nine of these highly variable regions (called V1 – V9) that display considerable differences in the genetic sequence between different groupings of bacteria. The V2 and V3 regions are considered the most suitable for distinguishing all bacterial species to the genus level (‘genus‘ being a method of classification).

Now scientist can amplify the 16S ribosomal RNA gene by making lots of copies of the highly conserved regions (using PCR) which are shared between bacteria, but then they will genetic sequence the variable sections in between (in this case V2 & V3), which will allow them to discriminate and quantify the different species of microorganisms (such as bacteria) within a particular sample.

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16S rRNA gene analysis – looks complicated. Source: Slideshare

And this is what the scientists in this study did.

They took fecal samples of 72 people with Parkinson’s disease and 72 control subjects, amplified the V1-V3 regions of the bacterial 16S ribosomal RNA gene, and then sequenced the variables regions in between to determine what sorts of bacteria were present (and/or different) in the guts of people with Parkinson’s disease.

The researchers found that there was a reduced abundance of Prevotellaceae in the guts of people with Parkinson’s disease (Prevotellaceae are commonly found in the gastric system of people who maintain a diet low in animal fats and high in carbohydrates, for example vegetarians).

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Prevotella multisaccharivorax which belongs to the Prevotellaceae family. Source: MindsofMalady

In addition, the investigators also reported a positive association between the abundance of Enterobacteriaceae and postural instability and gait difficulty symptoms – that is to say, people with Parkinson’s disease who also had postural instability and gait difficulties had significantly more Enterobacteriaceae in their guts than people with Parkinson’s disease who were more tremor dominant.

Due to the design of the study, the researchers were not able to make conclusions about causality from their study. Neither could they tell whether the microbiome changes were present before the onset of Parkinson’s disease or whether they simply developed afterwards. All they could really say was at the time of analysis, they did see a difference in the gut microbiota between people with and without Parkinson’s disease.

And while these same researchers are currently conducting a two year follow up study to determine the stability of these differences over time in the same subjects, they admit that much larger prospective studies are required to address such issues as causality.

Which brings us to the new research published last week:

gut-title

Title: Parkinson’s disease and Parkinson’s disease medications have distinct signatures of the gut microbiome.
Authors: Hill-Burns EM, Debelius JW, Morton JT, Wissemann WT, Lewis MR, Wallen ZD, Peddada SD, Factor SA, Molho E, Zabetian CP, Knight R, Payami H.
Journal: Mov Disord. 2017 Feb 14. [Epub ahead of print]
PMID: 28195358

The researchers in this study (completely independent from the previous study) applied the same study design as the previous study, but on a much larger scale:

They took samples from a total of 197 people with Parkinson’s disease and 130 healthy controls. And importantly, none of the individual subjects in the study were related (this was an attempt to reduce the effect of shared microbiota between people who live together). Participants were enrolled from the NeuroGenetics Research Consortium in the cities of Seattle (Washington), Atlanta (Georgia) and Albany (New York).

So what did they find?

The researcher’s data revealed alterations in at least 7 families of bacteria: Bifidobacteriaceae, Christensenellaceae, Tissierellaceae, Lachnospiraceae, Lactobacillaceae, Pasteurellaceae, and Verrucomicrobiaceae families

Of particular interest was their observation of reduced levels of Lachnospiraceae in Parkinson’s disease subjects. Lachnospiraceae is involved with the production of short chain fatty acids (SCFA) in the gut. Depletion of SCFA has been implicated in the pathogenesis of Parkinson’s disease (Click here for more on this), and it could potentially explain the inflammation and microglial cell activation observed in the brain (Click here for more on this).

Importantly, they did not replicate the association of Parkinson’s disease with Prevotellaceae (see the previous study above).

The investigators also looked at the medication that the subjects were taking and they found a significant difference in the gut microbiome in relation to treatment with COMT inhibitors and anticholinergics. The effects of COMT inhibitors and anticholinergics on hte microbiome was independent of the effect that Parkinson’s disease was having.

The investigators concluded that Parkinson’s disease is accompanied by ‘dysbiosis of gut microbiome’ (that is, microbial imbalance). Again they could not determine whether the ‘chicken came before the egg’ so to speak, but it will be interesting to see what follow up work in this study highlights.

What does it all mean?

The studies that we have reviewed today provide us with evidence that the bacteria in the guts of people with Parkinson’s disease are different to that of healthy control subjects. Whether the differences between the studies results are due to regional effects (Finland vs USA) will require further investigation. But given that so much attention is now focused on the role of the gut in Parkinson’s disease, it is interesting that there are differences in the gut microbiome between people with and without Parkinson’s disease.

One issue that both studies do not address is whether this difference is specific to Parkinson’s disease and not other neurodegenerative conditions. That is to say, it would have been very interesting if the investigators had included a small set of samples from people with Alzheimer’s disease, for example. This would indicate which differences are specific to Parkinson’s disease as opposed to differences that a general to individuals who have a neurodegenerative condition. If they can tease out medication-related differences (in the second study), then this should be a do-able addition to any future studies.

One would also hope that the researchers will go back and dig a little deeper with future analyses. Using 16S ribosomal RNA gene analysis to determine and quantify the different families of bacteria is analogous to dividing people according to hair and eye colour. The bacteria of our gut is a lot more complicated than this review has suggested. For example, future studies and follow up research could include some genetic techniques that go beyond simply sequencing the 16S ribosomal RNA gene. The investigators could sequence the entire genomes of these species of bacteria to see if genetic mutations within a particular family of bacteria is present in people with Parkinson’s disease.

Easy to say of course. A lot of work, in practise.

There is most likely going to be more of a focus on the gastrointestinal tract in Parkinson’s disease research as a result of these studies. It will be interesting to see where this research leads.


The banner for today’s post was sourced from Youtube

Pink flies in Leicester at it again

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Imagine discovering a protein that could make the power supply of your cells healthier AND perhaps provide a new therapeutic target for Parkinson’s disease.

That would be a pretty big deal right?

Well, this week, researchers may have found just such a protein. In today’s post we will review their finding and discuss what it means for Parkinson’s disease.


This is Dr Miguel Martins:

miguel_martins

Source: Tox.mrc.ac.uk

He’s a dude.

Dr Martins is a group leader at the MRC toxicology unit in Leicester – a city in the East Midlands of England.

leicester-town-hall-squareLeicester. Source: Keithvazmp

You may have heard of Leicester. Last year their football team had a dream season, miraculously winning the Premier league title despite starting with odds of 5000:1.

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Last season’s winners. Source: Goal.com

This season, however,….well, uh…

Let’s move on, shall we.

Recently we reviewed Dr Martins research group’s work on ‘Pink flies’ and how they survive longer on Niacin rich diets (Click here for that post). He and his group were again publishing research this week, involving new a new study highlighting a protein that may help with keeping mitochondria healthy.

What are mitochondria?

Good question.

Mitochondria are the power house of each cell. They keep the lights on. Without them, the lights go out and the cell dies.

Mitochondria

Mitochondria and their location in the cell. Source: NCBI

You may remember from high school biology class that mitochondria are bean-shaped objects within the cell. They convert energy from food into Adenosine Triphosphate (or ATP). ATP is the fuel which cells run on. Given their critical role in energy supply, mitochondria are plentiful and highly organised within the cell, being moved around to wherever they are needed.

So what has Dr Martins group found?

This week they published this study:

atf4

Title: dATF4 regulation of mitochondrial folate-mediated one-carbon metabolism is neuroprotective.
Authors: Celardo I, Lehmann S, Costa AC, Loh SH, Miguel Martins L.
Journal: Cell Death Differ. 2017 Feb 17. [Epub ahead of print]
PMID: 28211874       (This article is OPEN ACCESS if you would like to read it)

In the study, the researchers were interested in determining what changes occur in the flies that are missing the Parkinson’s disease associated genes PINK1 or PARKIN, particularly which transcription factors are affected.

What is a transcription factor?

Another good question.

Ok, so you remember your high school science class when the adult at the front of the class was explaining biology 101? And they were saying that DNA gives rise to RNA, RNA gives rise to protein? The central dogma of biology. Remember this?

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The basic of biology. Source: Youtube

Ultimately this DNA-RNA-Protein mechanism is a circular cycle, because the protein that is produced using RNA is required at all levels of this process. Some of the protein is required for making RNA from DNA, while other proteins are required for making protein from the RNA instructions.

A transcription factor is a protein that is involved in the process of converting (or transcribing) DNA into RNA.

Importantly, a transcription factor can be an ‘activator’ of transcription – that is initiating or helping the process of generating RNA from DNA.

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An example of a transcriptional activator. Source: Khan Academy

Or it can be a repressor of transcription – blocking the machinery (required for generating RNA) from doing it’s work.

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An example of a transcriptional repressor. Source: Khan Academy

In their study, Dr Martins and colleagues were looking for changes in the levels of proteins that either initiate or repress transcription, as these are the proteins that are ultimately at the start of the process of making things happen.

And what do Parkin and Pink1 actually do?

About 10% of cases of Parkinson’s disease can be attributed to genetic mutations in particular genes. PINK1 and PARKIN are two of those genes.

People with particular mutations in the PINK1 or PARKIN gene are vulnerable to developing an early onset form of Parkinson’s disease.

As to what the protein that is generated from PINK1 or PARKIN DNA & RNA, well in normal, healthy cells, the PINK1 protein is absorbed by mitochondria and eventually degraded. In unhealthy cells, however, this process is inhibited and PINK1 starts to accumulate on the outer surface of the mitochondria. There, it starts grabbing the PARKIN protein. This pairing is a signal to the cell that this particular mitochondria is not healthy and needs to be removed.

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Pink1 and Parkin in normal (right) and unhealthy (left) situations. Source: Hindawi

The process by which mitochondria are removed is called autophagy. Autophagy is an absolutely essential function in a cell. Without it, old proteins will pile up making the cell sick and eventually it dies. Through the process of autophagy, the cell can break down the old protein, clearing the way for fresh new proteins to do their job.

Think of autophagy as the waste disposal process of the cell.

In the absence of PINK1 and PARKIN – as is the case in some people with Parkinson’s disease who have genetic mutations in these genes – we believe that sick/damaged mitochondria start to pile up and are not disposed of appropriately. This results in the cell dying.

Ok, so the researchers were looking for transcription factors that change in the absence of PINK1 and PARKIN. How did they do this experiment?

They used flies.

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PINK flies. Source: Wallpapersinhq

The researchers took the heads (yes, I know, delightful stuff) of ‘young’ 3-day-old Pink1 and Parkin mutant flies and compared them to ‘aged’ heads from 21- and 30-day-old Parkin and Pink1 mutant flies, respectively. The comparison was specifically looking at transcription factors that change over time.

This analysis revealed a protein called activating transcription factor 4 (or ATF4).

The researchers found that ATF4 levels were higher in both Pink1 and Parkin mutants than levels in control flies. Importantly, the researchers next looked at the genes that this transcription factor (ATF4) was regulating, and they found that ATF4 was encouraging the production of proteins that protect mitochondria. The researchers noticed that when they reduced ATF4 in flies, the levels of these critical mitochondrial proteins dropped as well.

When the researchers reduced the levels of each of these critical mitochondrial proteins in flies, it resulted in impaired climbing ability (suggesting a locomotor deficit) and decreased lifespan. Interestingly, these protective mitochondrial proteins are increased in the Pink1 and Parkin flies, suggesting that efforts to keep the mitochondria healthy are active inside the cells.

Finally, the researchers increased the levels of these protective mitochondrial proteins in the Pink1 and Parkin mutants and they found that the mitochondrial function was improved, and neuronal cell loss was avoided. They concluded that their findings demonstrate a central role for ATF4 signalling in Parkinson’s disease and that this protein may represent a target for new therapeutic strategy.

So what does it all mean?

The researchers behind this study were looking for biological pathways that are altered in genetic forms of Parkinson’s disease and they have identified a protein that is involved with keeping mitochondria healthy. This pathway could represent a new therapeutic target for future treatments, and also opens a new door in our understanding of Parkinson’s disease.

ATF4 is currently not directly targeted by any medications (that we are aware of), but there are drugs in clinical trials that target proteins that subsequently activate ATF4. For example, Oncoceutics Inc. have a drug candidate called ONC201 (currently in phase II trials for brain cancer) which kills solid tumor cells by triggering an stress response which is dependent on ATF4 activation.

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Source: Oncoceutics Inc

We are not for a second suggesting that this is a viable drug for Parkinson’s disease (so PLEASE DON’T rush out and besiege the company for all of their stocks!) – ATF4 should be considered a very experimental target until these results are replicated by independent research groups. We are mentioning ONC201 here simply to indicate that there is a field of research surrounding this potential target (ATF4) and it may be worthwhile for the Parkinson’s community to follow up this line of investigation.

We are assuming that while Leicester football club is struggling, the Martins lab are currently investigating compounds that activate ATF4 (and the other critical mitochondrial proteins), and we will report any follow up work as it comes to hand.

Watch this space.


And if nothing we’ve written here makes any sense, the good folks at Leicester University have kindly provided a short video explaining the research:


Postscript (March 2017):

matters_journal

The Martins lab have done it again!

This time in the OPEN ACCESS online journal Science Matters, they have published this article:

Matters

Title: Folinic acid is neuroprotective in a fly model of Parkinson’s disease associated with pink1 mutations
Authors: Lehmann S , Jardine J, Garrido – Maraver J, Loh SH, & Martins LM
Journal: Science Matters

In this study, the researchers demonstrated that a folinic acid-enriched diet might delay or prevent the neuronal loss in people with PINK1 associated Parkinson’s disease. They present data suggesting that beginning an intake of Folinic acid in early to middle stages of adulthood prevents the degeneration of dopamine neurons in pink1 mutant flies.

Folinic acid (also known as leucovorin) is a medication used to decrease the toxic effects of chemotherapy drugs. The pharmacokinetics of leucovorin suggests that it readily crosses the blood-brain-barrier (Source), so it would be possible for a clinical trial to be set up in human. Before taking that path, however, more testing is required (ideally in a mammalian model of Parkinson’s disease).

Amazing that all these results are coming from silly old flies though, huh?


The banner for today’s post was sourced from Tox.mrc.ac.uk

HIV and Parkinson’s disease

hiv-aids-definition2

 

I was recently made aware of an interesting fact:

Approximately 5% of people with Human immunodeficiency virus (HIV) infections develop Parkinson’s disease-like features.

Why is this?

In today’s post we will try to understand what is going on, and what it may mean for Parkinson’s disease.


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HIV (in green) budding (being released) from a blood cell (lymphocyte). Source: Wikipedia

Ok, let’s start at the beginning:

What is HIV?

Human immunodeficiency virus (or HIV) – as the name suggests – is the virus.

It causes the infection which gives rise to Acquired Immune Deficiency Syndrome (or AIDS). AIDS is a progressive failure of the immune system – the body loses its ability to fight infections. Without treatment, average survival period after infection with HIV is between 9 – 12 years.

HIV can be spread by the transfer of bodily fluids, such as blood and semen. The World Health Organisation (WHO) has estimated that approximately 36.9 million people worldwide were living with HIV/AIDS at the end of 2014 (that is equivalent to the entire population of Canada!).

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The structure of the HIV virus. Source: Wikipedia

Does HIV affect the brain?

Yes.

At postmortem examinations, less than 10% of the brains from HIV infected individuals are histologically normal (Source).

HIV is a member of the lentivirus family of viruses, which readily infect immune cells (such as blood cells). HIV can also infect other types of cells though, including those in the brain. HIV will usually enter the central nervous system within the first month following infection. It enters the brain via infected blood cells which come into contact with brain ‘immune system/helper’ cells such as microglia and macrophages at the blood-brain-barrier.

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How HIV enters the brain. Source: Disease Models and Mechanisms

HIV can also infect astrocytes (albeit at a lower frequency than microglia and macrophages), by direct cell-cell contact with infected T cells (blood cells) at the blood-brain-barrier (No. 1 in the image above). After infecting astrocytes, there is dysfunction in the astrocyte and it will no longer be so supportive to the local neurons (No. 2 in the image above). Once inside the brain, HIV-infected macrophages will allow for infection of other macrophages and microglia (No. 3 in the image above), and all together these HIV-infected astrocytes and microglia will cause damage to neurons by releasing viral proteins (two in particular, called Tat and gp120) and additional nasty chemicals which are bad for the neurons (No. 4 in the image above). Finally, as the disease progresses, the protective layer of the blood-brain-barrier becomes compromised and HIV-infected T cells eventually enter the brain and they cause damage to neurons by releasing pro-inflammatory chemicals (making the environment harsh for neurons).

There is remarkably little evidence of HIV actually infecting neurons (Click here for a review on this), so any cell loss in the brain that is associated with HIV does not result from neurons themselves being infected. This may be due to the fact that neurons do not have the HIV receptors (such as CD4) on their cell membrane. Similarly, oligodendrocytes (a supporting cell) does not appear to be easily infected by HIV. The bulk of the infected cells in the brain appear to be of the microglial, macrophage and astrocytes. And without these supporting cells doing their jobs in a normal fashion, it is easy to see how neurons can start dying off.

The severity, characteristics and distribution of HIV-induced injury in the brain varies greatly between affected individuals. It is most likely associated with the viral load (or the number of viral particles) in the brain, which can vary from a few thousand to more than a million copies per mL.

Do HIV-infected people show any signs of the virus entering the brain?

For the majority of people infected with HIV, this entry of the virus into the nervous system is neurologically asymptomatic (meaning they will not notice it), except for the occasional mild headache (for more on this read this review). As a result of the HIV virus entering the brain, however, many infected individuals will suffer from a specific set of neurological disorders, collectively called the AIDS dementia complex (ADC) (also known as HIV-associated cognitive/motor complex, or simply HIV dementia).

So how does HIV infection result in Parkinson’s disease-like features?

As we have suggested in the introduction to this post, on rare occasions (approximately 5% of cases), HIV-infected patients may present an illness virtually identical to Parkinson’s disease. More commonly, people with HIV will exhibit an increased sensitivity to dopamine receptor-blocking agents, such as drugs with a low potential for inducing Parkinsonism, (for example prochlorperazine and metoclopropamide).

The exact mechanism by which HIV infection results in Parkinson’s disease-like features is the subject of debate, but what is clear is that the basal ganglia (a structure involved in Parkinson’s disease) faces the brunt of the HIV infection in the brain. HIV-infected microglia and macrophage are most prominent in the basal ganglia when compared to other brain regions (Click here and here for more on this), and the basal ganglia is where the chemical dopamine from the midbrain is being released.

In addition, there are other changes in the brains of HIV infected people which may aid in the appearance of Parkinsonian features:

 

viraltitle

Title: Increased frequency of alpha-synuclein in the substantia nigra in human immunodeficiency virusinfection.
Authors: Khanlou N, Moore DJ, Chana G, Cherner M, Lazzaretto D, Dawes S, Grant I, Masliah E, Everall IP; HNRC Group.
Journal: J Neurovirol. 2009 Apr;15(2):131-8.
PMID: 19115126       (This article is OPEN ACCESS if you would like to read it)

The researchers in this study used staining techniques to look at the amount of alpha synuclein – the Parkinson’s associated protein – in slices of brain tissue taken from postmortem autopsies of 73 HIV+ individuals aged between 50 and 76 years of age.

The presence of alpha synuclein in the substantia nigra (an area of the brain affected by Parkinson’s disease) was a lot higher in the HIV+ brains when compared with healthy control samples (16% of the HIV+ brains had high levels of alpha synclein vs 0% for the healthy brains).

Interestingly, nearly all of the brains analysed (35 out of 36 HIV+ brains) had high levels of the Alzheimer’s disease associated protein, beta amyloid (which again raises the question of whether beta amyloid could be playing a defensive role in infections – see our previous post on this). Also interesting, was that there was no correlation between these proteins being present and the age of the person at death – that is to say, older brains did not have more of these proteins when compared with younger brains.

There are also additional ways in which HIV could be causing Parkinson’s-like features, such as:

  • HIV has been shown to affect the protein levels of Parkinson’s disease associated proteins, such as DJ1 and Lrrk2 (Click here and here to read more on this).
  • HIV can, in some cases, increase the level of Dopamine transporter, which would reduce the levels of free floating dopamine in the brain (Click here to read more about this).

How is HIV treated?

aidspills

Treating HIV. Source: NPR

There is currently no cure for HIV infection.

There are, however, treatments which help to slow the virus down. These are called Anti-retroviral drugs (HIV is a retrovirus). There are different kinds of anti-retroviral drugs, which act at different stages of the HIV life cycle. Combinations of several anti-retroviral drugs (generally three or four) is known as ‘Highly Active Anti-Retroviral Therapy'(or HAART).

hiv-drug-classes-svg

Mechanism by which four classes of anti-retroviral drugs work against HIV. Source: Wikipedia

As the schematic image above highlights, there are many ways to slow down the HIV virus. For example, you can prevent it from attaching to a cell and fusing with the cell membrane (fusion inhibitors). By treating HIV infected people with multiple medications attacking different parts of the HIV life cycle, the virus has been slowed down.

Does HAART treatments for HIV help with these Parkinson’s-like features?

In some cases, the answer appears to be yes.

There are numerous case studies in the literature which demonstrate the alleviation of HIV-associated Parkinsonian symptoms with HAART, such as this report:

hersh

Title: Parkinsonism as the presenting manifestation of HIV infection: improvement on HAART.
Authors: Hersh BP, Rajendran PR, Battinelli D.
Journal: Neurology. 2001 Jan 23;56(2):278-9.
PMID: 11160977

In this study the researchers described the case of a 37 year old man who developed Parkinson’s like features in the setting of an HIV infection, which were resolved after 1 year of HAART.

Over a period of 4 months, the man developed co-ordination issue, clumsiness and an irregular tremor in his right hand (there was, however, no resting tremor). He noted a generalised slowness and exhibited a tendency towards decreased right arm swinging. He also developed dystonia in the right hand/arm. Following L-dopa treatment (25/100; one tablet 3x per day) there was improvement in balance & co-ordination, speech, facial expression, and the tremor (L-dopa does appear to improve most cases of HIV-associated Parkinson’s-like features).

Six months after first displaying these Parkinsonian features (and two month after initiating L-dopa treatment), the subject was placed on HAART treatment. Four months later, he discontinued L-dopa treatment and 12 months after starting the HAART regime his Parkinsonian features were largely resolved.

More case studies of HAART alleviating HIV-associated Parkinsonisms can be found by clicking here and here.

What does this mean for Parkinson’s disease?

This post was written for the research community rather than people with Parkinson’s disease. I thought the fact that some people with HIV can start to have Parkinson’s like features was an interesting curiosity and wanted to share/spread the information.

Having said that, this post raises some really interesting questions, such as if a virus like HIV can have this effect on the brain, could other viruses be having similar effects? Could some cases of Parkinson’s disease simply be the result of a viral infection? Either multiple hits from a particular virus or different viruses each taking a varying toll over the course of a life time.

This idea would explain many of the curious features of Parkinson’s disease, such as:

  • the asymmetry of the symptoms (people with Parkinson’s usually have the disease starting on one side of the body.
  • the fact that some cells in the brain are more vulnerable to the disease than others (perhaps they are more receptive to a particular virus).
  • the protein clusterings in the cells (Lewy bodies may be defensive efforts against viral infections).

As we have previous mentioned, theories of viral causes for Parkinson’s have been circulating ever since the 1918 flu pandemic (Click here to read our previous post on this topic). About the same time as the influenza virus was causing havoc around the world, another condition began to appear called ‘encephalitis lethargica‘. This disease left many of the victims in a statue-like condition, both motionless and speechless – similar to Parkinson’s disease. Initially, it was assumed that the influenza virus was the causal factor, but more recent research has left us not so sure anymore.

The point is, however, perhaps it is time for us to re-examine the possibility of a viral agent being involved in the development of Parkinson’s disease.

There is new technology that allows us to determine the viral history of each individual from a simple blood test (Click here for more on this), so it would be interesting to compare blood samples from people with Parkinson’s disease with healthy controls to determine any differences.

In addition to the overall question of a viral role in Parkinson’s disease, there also remains the question of why only a small fraction of people with HIV are affected by Parkinsonisms. It could be interesting to genetically screen those people with HIV that exhibit Parkinsonisms and compare them with people with HIV that do not. Do those affected individuals have recognised Parkinson’s related genetic mutations? Or do they have novel genetic variations that could tell us more about Parkinson’s disease?

Food for thought. Would be happy to hear others thoughts.


The banner for today’s post was sourced from AidsServices

Busy day for Parkinson’s – 9/2/2017

 

o-busy-facebook

Today there was a lot of Parkinson’s related activity in the news… well, more than usual at least.

Overnight there was the publication of a blood test for Parkinson’s disease, which looks very sensitive. And this afternoon, Acorda Therapeutics announced positive data for their phase three trial.

In this post, we’ll look at what it all means.


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Blood cells. Source: Reference.com

Today we found out about an interesting new study from scientists at Lund University (Sweden), where they are developing a test that can differentiate between different types of Parkinsonisms (See our last post about this) using a simple blood test.

We have previously reported about an Australian research group working on a blood test for Parkinson’s disease, but they had not determined whether their test could differentiate between different kinds of neurodegenerative conditions (such as Alzheimer’s disease). And this is where the Swedish study has gone one step further…

blood
Title: Blood-based NfL: A biomarker for differential diagnosis of parkinsonian disorder
Authors: Hansson O, Janelidze S, Hall S, Magdalinou N,  Lees AJ, Andreasson U, Norgren N, Linder J, Forsgren L, Constantinescu R, Zetterberg H, Blennow K, & For the Swedish BioFINDER study
Journal: Neurology, Published online before print February 8, 2017
PMID: N/A       (This article is OPEN ACCESS if you would like to read it)

The research group in Lund had previously demonstrated that they could differentiate between people with Parkinson’s disease and other types of Parkinsonism to an accuracy of 93% (Click here to read more on this). That is a pretty impressive success rate – equal to basic clinical diagnostic success rates (click here for more on this).

The difference was demonstrated in the levels of a particular protein, neurofilament light chain (or Nfl). NfL is a scaffolding protein, important to the cytoskeleton of neurons. Thus when cells die and break up, Nfl could be released. This would explain the rise in Nfl following injury to the brain. Other groups (in Germany and Switzerland) have  also recently published data suggesting that Nfl could be a good biomarker of disease progression (Click here to read more on this).

There was just one problem: that success rate we were talking about above, it required cerebrospinal fluid. That’s the liquid surrounding your brain and spinal cord, which can only be accessed via a lumbar puncture – a painful and difficult to perform procedure.

lumbar-puncture-cropped

Lumbar puncture. Source: Lymphomas Assoc.

Not a popular idea.

This led the Swedish researchers to test a more user friendly approach: blood.

In the current study, the researchers took blood samples from three sets of subjects:

  • A Lund set (278 people, including 171 people with Parkinson’s disease (PD), 30 people with Multiple system atrophy (MSA), 19 people with Progressive Supranuclear Palsy (PSP), 5 people with corticobasal syndrome (CBS), and 53 people who were neurologically healthy (controls).
  • A London set (117 people, including 20 people with PD, 30 people with MSA, 29 people with PSP, 12 people with CBS, and 26 neurologically healthy controls
  • An early disease set (109 people, including 53 people with PD, 28 people with MSA, 22 people with PSP, 6 people with CBS). All of the early disease set had a disease duration less than 3 years.

When the researchers looked at the levels of NfL in blood, they found that they could distinguish between people with PD and people with PSP, MSA, and CBS with an accuracy of 80-90% – again a very impressive number!

One curious aspect of this finding, however, is that the levels of Nfl in people with PD are very similar to controls. So while this protein could be used to differentiate between PD and other Parkinsonisms, it may not be a great diagnostic aid for determining PD verses non-PD/healthy control.

In addition, what could the difference in levels of Nfl between PD and other Parkinsonisms tell us about the diseases themselves? Does PD have less cell death, or a more controlled and orderly cell death (such as apoptosis) than the other Parkinsonisms? These are questions that can be examined in follow up work.


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Source: 3rd-Solutions

Like we said at the top, it’s been a busy day for Parkinson’s disease: Good news today for Acorda Therapeutics, Inc.

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Source: Acorda

They announced positive Phase 3 clinical trial results for their inhalable L-dopa treatment, called CVT-301, which demonstrated a statistically significant improvement in motor function in people with Parkinson’s disease experiencing OFF periods.

We have previously discussed the technology and the idea behind this approach to treating Parkinson’s disease (Click here for that post).

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The ARCUS inhalation technology. Source: ParkinsonsLife

Basically, the inhaler contains capsules of L-dopa, which are designed to break open so that the powder can escape. By sucking on the inhaler (see image below), the open capsule starts spinning, releasing the levodopa into the air and subsequently into the lungs. The lungs allow for quicker access to the blood system and thus, the L-dopa can get to the brain faster. This approach will be particularly useful for people with Parkinson’s disease who have trouble swallowing pills/tablets – a common issue.

The Phase 3, double-blind, placebo-controlled clinical trial evaluated the efficacy and safety of CVT-301 when compared with a placebo in people with Parkinson’s disease who experience motor fluctuations (OFF periods). There were a total of 339 study participants, who were randomised and received either CVT-301 or placebo. Participants self-administered the treatment (up to five times daily) for 12 weeks.

The results were determined by assessment of motor score, as measured by the unified Parkinson’s disease rating scale III (UPDRS III) which measures Parkinson’s motor impairment. The primary endpoint of the study was the amount of change in UPDRS motor score at Week 12 at 30 minutes post-treatment. The change in score for CVT-301 was -9.83 compared to -5.91 for placebo (p=0.009). A negative score indicates an improvement in overall motor ability, suggesting that CVT-301 significantly improved motor score.

The company will next release 12-month data from these studies in the next few months, and then plans to file a New Drug Application (NDA) with the Food and Drug Administration (FDA) in the United States by the middle of the year and file a Marketing Authorization Application (MAA) in Europe by the end of 2017. This timeline will depend on some long-term safety studies – the amount of L-dopa used in these inhalers is very high and the company needs to be sure that this is not having any adverse effects.

All going well we will see the L-dopa inhaler reaching the clinic soon.


 

The banner for today’s post was sourced from the Huffington Post

George H and Vascular Parkinsonism

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During Super Bowl 51, ex-president George HW Bush was visibly wheel chair bound. He has in fact been using motorised scooters and wheelchairs since 2012.

His doctors have indicated that he suffers from Vascular Parkinsonism.

In today’s post we will discuss what Vascular Parkinsonism is and how it differs from Parkinson’s disease.


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During a visit to the White house. Source: Heavy

An important concept to understand about the subject matter here:

Parkinsonism is a syndrome, while Parkinson’s is a disease.

A syndrome is a collection of symptoms that characterise a particular condition, while a disease is a pathophysiological response to internal or external factors. The term ‘Parkinsonism’ is an umbrella term that encompasses many conditions which share some of the symptoms of Parkinson’s disease.

There are many different types of Parkinsonism, such as:

  • Idiopathic Parkinson’s disease (the most common type of parkinsonism)
  • Progressive Supranuclear Palsy (PSP)
  • Corticobasal Degeneration (CBD)
  • Multiple System Atrophy (MSA)
  • Essential tremor
  • Vascular Parkinsonism
  • Drug-induced Parkinsonism
  • Dementia with Lewy bodies
  • Inherited Parkinson’s disease
  • Juvenile Parkinson’s disease

All of these conditions fall under the syndrome title of ‘Parkinsonism’, but are all considered distinct/separate diseases in themselves.

So what is Vascular Parkinsonism?

Vascular Parkinsonism was first described in 1929 by Dr Macdonald Critchley (King’s College Hospital, London).

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Macdonald Critchley. Source: Npgprints

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Title: Arteriosclerotic Parkinsonism.
Author: Critchley, M.
Journal: Brain (1929) 52, 23–83
PMID: N/A                                (this article is accessible by clicking here)

It is estimated that approximately 3% to 6% of all cases of Parkinsonism may have a vascular cause. Vascular (or Arteriosclerotic) Parkinsonism is results from a series of small strokes in the basal ganglia area of the brain and can lead to the appearance of symptoms that look like Parkinson’s disease: slow movements, tremors, difficulty walking, and rigidity.

Walking problems are particularly prominent with Vascular Parkinsonism, as the lower half of the body is usually more affected than the upper half. Another sign of Vascular Parkinsonism can be a poor or no response to L-dopa treatment, as production of dopamine is not the problem. Using brain scanning techniques we can see that some people with Vascular Parkinsonism will have a normal Dopamine transporter (DAT) scan – which demonstrates appropriate levels of dopamine being released and reabsorbed in the striatum (the red-white areas in the image below).

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DAT-scan and MR images of 62-y-old male  with Vascular Parkinsonism (A) and 62-y-old male with Parkinson’s disease (B). Source: JNM

The brain scans above are from a person with Vascular Parkinsonism (A) and another person with Parkinson’s disease (B). Firstly, note the reduced levels of red-white areas in the image (B) – this reduction is due to less dopamine is being released and reabsorbed in the striatum in Parkinson’s disease (as there are less dopamine fibres present). Compare that with the relatively normal levels of red-white areas in the image (A), indicating normal levels of dopamine turnover (suggesting dopamine fibres are still present). Next, look at the black and white image in panel (A) and you will see a red arrow pointing at damaged areas (darkened regions) of the striatum – indicative of mini strokes. A dopamine receptor scan may show a reduction in the levels of dopamine receptors as a result of the strokes, meaning that the released dopamine will not be having much effect.

Do we know what can cause the strokes associated with Vascular Parkinsonism?

The symptoms of Vascular Parkinsonism tend to appear suddenly and generally do not progress, unlike Parkinson’s disease. We don’t know for sure what causes the mini strokes associated with Vascular Parkinsonism, and it probably varies from person to person, In general, however, doctors believe that high blood pressure and diabetes are the most likely causal factors (heart disease may also play a role).

What does it all mean?

Some people of Parkinson’s disease may actually have Vascular Parkinsonism, which can result from mini strokes in the basal ganglia region of the brain. They will usually be unresponsive to L-dopa and have more motor issues with their lower half of the body.

While Ex-President George HW Bush’s situation is extremely unfortunate, it reminds us that not all forms of Parkinsonism are Parkinson’s disease – an important factor to keep in mind when considering treatment regimes. We have posted this information here to make the Parkinson’s community more aware of this form of Parkinsonism. Later in the year we will discuss another form of Parkinsonism.


The banner for today’s post was sourced from Ew

On bans and boycotts

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Here at the SoPD we are politically neutral.

That said, we will report on events that directly impact the world of Parkinson’s disease research (without adding any personal opinions). This week a vote took place that may have implications for the Parkinson’s disease research community over the coming year.

Here we will discuss what has happened and what it means for the Parkinson’s research community.


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Researchers voting. Source: Science

On the 3rd February, the organising committee of the Commission G2 Massive Stars, part of the International Astronomical Union (IAU) announced that it would not hold any scientific meetings in the United States of America as long as a temporary ban on the entry of any persons from Libya, Sudan, Somalia, Syria, Iran, Iraq, and Yemen, is in place.

This vote was in response to the January 27th signing of Executive Order 13769, which limits the number of refugees arriving in the USA to just 50,000 and suspended the US Refugee Admissions Program (USRAP) for 120 days (after which the program will be resumed with new conditions for individual countries). The order also imposes a temporary travel ban on the 7 countries listed above for 90 days, after which an updated list will be made. Notably the suspension for Syrian refugees is indefinite, but the order allows for exceptions to be made on a case-by-case basis. (Source: Wikipedia).

With just 12,450 individual members (from 74 countries, including Iran), the IAU’s decision is purely a small symbolic gesture. And while their vote has nothing to do with Parkinson’s disease, we note that other scientific research organisations (and many individual scientists) are making/contemplating similar measures/gestures – not simply calls to boycott US-based conferences but also particular scientific journals (for more on this click here).

Of particular importance to the Parkinson’s community is the Society for Neuroscience (SfN) meeting to be held in Washington DC in November of this year (luckily the annual Parkinson’s disease and Movement disorder conference will be held in Vancouver this year). Each year, 30-40,000 scientists and advocates from around the world gather at these SfN meetings to share/discuss novel findings and form new collaborations. A great deal of Parkinson’s research is discussed at these meetings and the associated satellite meetings that take place the week before or after.

The president of the SfN has already issued a press release regarding the executive order (Click here to read that), but many researchers are already pulling out of invited presentations. For example, Adrian Owen, a well-known neuroscientist from Western University (Ontario) publicly announced on twitter that he was refusing an invitation to present a lecture at the meeting in Washington DC:

At the time of publishing this post, a federal appeals court had denied a Justice Department’s request to lift the restraining order and allow the immigration ban to continue. The 9th U.S. Circuit Court of Appeals in San Francisco has asked for the Justice Department to file a counter-response by 3pm Monday (Click here to see that statement), which means that the restraining order remains in place for the next 24 hours at least.

Whether the restraining order is lifted and Executive Order 13769 is brought back into effect is a matter for the courts to decide. The outcome, however, is already having an impact as many scientists symbolically refuse to attend conferences in the US (it will be interesting to see what attendance is this year at the SFN meeting).

We are not going to speculate on the possible consequences of Executive Order 13769, except to say that 2017 may not be a bonanza for US based research conferences. We will be watching events as they unfold and will discuss them here if they relate to the Parkinson’s community.


The banner for today’s post was sourced from ABC News

PARIS is always a good idea

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Audrey Hepburn was taking about the city when she uttered the words that title this post, but today we will be talking about the protein that bears the same name: PARIS.

Last week new research was published which demonstrated that in the absence of Parkin and Pink1 protein, the protein PARIS builds up and becomes toxic for cells.

Today’s post will review that research and we’ll discuss what it all means for Parkinson’s disease.


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No label required. A magnificent city. Source: HathawaysofHaworth

Today’s post has nothing to do with the city of Paris, but it is always nice to have photos of this European capital gracing the page.

We have recently discussed the Parkinson’s associated proteins Pink1 and Parkin (click here for that post). Today we will be revisiting these proteins as we discuss another protein that they interact with: PARIS (specifically PARIS1).

What is PARIS?

PARIS (aka TBC1D2 or TBC1 Domain Family Member 2) is a GTPase-activating protein.

What does that mean?

Getting a signal from outside of a cell into the interior is a complicated affair. There are numerous ways to do it, but one of the most common involves ‘G-proteins‘. These are involved with transmitting a signal from the outside of a cell into the interior, and when inside the cell G-proteins act as molecular switches.

G-proteins are located inside the cell membrane and are activated by G-protein-coupled receptors. When a signaling molecule binds to the G-protein-coupled receptor on the outside of the cell membrane, the portion of the receptor inside the cell activates the G-protein which then starts of a chain of events resulting in the signal being passed on.

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Source: Bio1151

The role of GTPase-Activating Proteins in this process is to turn the G protein’s activity off. In step 4 of the image above, a GTPase-Activating Protein (which is not shown) binds to the G-protein and terminate the activity of the signalling event – returning it to an inactive state.

Thus, GTPase-Activating Proteins – like PARIS – are important regulators of signalling inside the cell.

What do we know about PARIS1 in Parkinson’s disease?

So a few years ago, a group of researchers led by Prof Ted Dawson at John Hopkins School of Medicine published this study:

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Title: PARIS (ZNF746) repression of PGC-1α contributes to neurodegeneration in Parkinson’s disease.
Authors: Shin JH, Ko HS, Kang H, Lee Y, Lee YI, Pletinkova O, Troconso JC, Dawson VL, Dawson TM.
Journal: Cell. 2011 Mar 4;144(5):689-702.
PMID: 21376232        (This article is OPEN ACCESS if you would like to read it)

In this study, the researchers noticed that the protein PARIS was accumulating in cells that did not have the Parkinson’s associated protein, Parkin. In those cells, the Parkin gene was mutated so that the Parkin protein was not produced properly. The researchers discovered that Parkin was important for labelling old PARIS protein for disposal. Thus in the absence of Parkin, PARIS protein would not be disposed of and simply piled up.

This build up of PARIS resulted in the loss of dopamine neurons in mice that did not produce Parkin. When the researchers re-introduced normal Parkin protein, the researchers were able to rescue the cell loss. Interestingly, the researchers also found that over production of PARIS in normal mice resulted in cell loss which could be rescued by a similar over production of Parkin.

When they looked in postmortem human brains, the researchers found that levels of PARIS protein were more than two times higher in regions affected by Parkinson’s disease (the striatum and the substantia nigra) of people with sporadic Parkinson’s disease when compared to healthy controls. Interestingly, this increase was only seen with PARIS protein, and not PARIS RNA (where the scientists saw no different with control samples), suggesting a build up of PARIS protein in the Parkinsonian brain.

The investigators concluded that this meant PARIS was could be playing a role in the cell loss associated with Parkinson’s disease.

They followed up this research a few years later with this publication:

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Title: Parkin loss leads to PARIS-dependent declines in mitochondrial mass and respiration.
Authors: Stevens DA, Lee Y, Kang HC, Lee BD, Lee YI, Bower A, Jiang H, Kang SU, Andrabi SA, Dawson VL, Shin JH, Dawson TM.
Journal: Proc Natl Acad Sci U S A. 2015 Sep 15;112(37):11696-701.
PMID: 26324925     (This article is OPEN ACCESS if you would like to read it)

In this study, the same researchers found that when they remove the Parkin protein from the brains of adult mice there would be a decrease in the size and number of mitochondria. We have previous discussed mitochondria – the power stations of the cell – and their loss is bad news for a cell (click here to read more on mitochondria).

The researchers next demonstrated that this loss of mitochondria could reversed by removing PARIS protein from the Parkin mutant mice, and this prevented the loss of dopamine neurons. They also showed that the loss of mitochondria (and loss of dopamine neurons) could be caused by over production of PARIS in normal mice.

These results pointed towards an important role for both Parkin and PARIS in the maintenance of healthy mitochondria.

So what new research has been published about PARIS1?

This study was published last week:

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Title: PINK1 Primes Parkin-Mediated Ubiquitination of PARIS in Dopaminergic Neuronal Survival.
Authors: Lee Y, Stevens DA, Kang SU, Jiang H, Lee YI, Ko HS, Scarffe LA, Umanah GE, Kang H, Ham S, Kam TI, Allen K, Brahmachari S, Kim JW, Neifert S, Yun SP, Fiesel FC, Springer W, Dawson VL, Shin JH, Dawson TM.
Journal: Cell Rep. 2017 Jan 24;18(4):918-932.
PMID: 28122242       (This article is OPEN ACCESS if you would like to read it)

In their study the researchers found that Parkin is not the only Parkinson’s associated protein in the PARIS story.

We have previously talked about the protein Pink1 (click here to read more on) – and yes, you would be forgiven if you start to think that all Parkinson’s related proteins start with the latter ‘P’. Pink1 grabs Parkin and causes it to bind to dysfunctional mitochondria. Parkin then signals to the rest of the cell for that particular mitochondria to be disposed of. In this study, the researchers found that Pink1 also grabs PARIS and signals for Parkin to dispose of it. In the absence of Pink1, normal Parkin protein does not label old PARIS protein for disposal and PARIS starts to pile up.

The researchers then began manipulating the levels of Pink in the brains of mice and they observed PARIS-dependent cell loss – that is to say, in the absence of Pink1, cells died only when PARIS was present.

These findings suggest that therapies targeting PARIS could be used in people with Parkinson’s disease who are carrying either a Parkin or a Pink1 mutation (both very common in early onset Parkinson’s disease).

What does it all mean?

People with early onset Parkinson’s disease quite often have a genetic mutation in one of a small number of genes – Pink1 and Parkin being prominent amongst these genes. The researchers who conducted the study that we have reviewed today have identified a common mechanism by which both of these proteins could be acting in their roles in Parkinson’s disease: a protein called PARIS.

Currently there is no treatment (that we are aware of) that targets the PARIS protein – nothing in the clinic nor being experimentally tested. Obviously, however, PARIS represents a VERY interesting protein for further investigations. The Dawson lab has several patents on PARIS (Click here and here for more on these), so evidently people will be working on drug candidates that inhibit PARIS.

There is a naturally occurring inhibitor, a micro RNA cluster miR-17-92 (also known as oncomir-1), which reduces the production of PARIS protein by blocking PARIS RNA (Click here for more on this). Using this micro RNA to target PARIS will be very difficult (both activating/delivering the micro RNA and unknown off target effects).

We are assuming that Prof Dawson and colleagues are rapidly screening compounds to determine which can block or inhibit PARIS activity and we will eagerly wait to see the results of that work.

Watch this space.


The banner for today’s post was sourced from Wallpapercave


EDITORIAL NOTE: Yay, 100 posts!