Tag: AADC

Not dead, dormant dopamine neurons?!?

~ Simon ~ 11 Comments

 

Every textbook written about the condition will tell you that the classical pathological characteristic of Parkinson’s is the loss of dopamine neurons in the midbrain region of the brain. It is the distinguishing feature that pathologists look for in order to provide a postmortem diagnosis of the condition.

But what is meant by the words ‘loss of dopamine neurons’? Do the cells actually die? Recently researchers from Korea have published new data exploring this question.

Interestingly, they found evidence of ‘dormant’ dopamine neurons in postmortem sections of brains from people with Parkinson’s – even those with severe forms of the condition.

In today’s post, we will discuss what a dopamine neuron is, what this new research found, and what it could mean for our understanding of Parkinson’s.

 

Source: Bettys

2019 represented the centenary year for an important discovery in Parkinson’s research.

In 1919, the Uzbek neuropathologist Konstantin Tretiakoff (1892-1958) reported his findings regarding an examination of 54 human brains.

Konstantin Tretiakoff. Source: Wikipedia

Six of the postmortem brains had belonged to individuals who had suffered from Parkinson’s and three others had been diagnosed with postencephalitic Parkinsonism. In these brains he noticed something rather striking.

What did he find?

Continue reading “Not dead, dormant dopamine neurons?!?” →

When undruggable becomes druggable

~ Simon ~ 3 Comments

Nuclear receptor related 1 protein (or NURR1) is a protein that has been shown to have a powerful effect on the survival of dopamine neurons – a population of cells in the brain that is severely affected by Parkinson’s.

For a long time researchers have been searching for compounds that would activate NURR1, but the vast majority of those efforts have been unsuccessful, leaving some scientists suggesting that NURR1 is “undruggable” (meaning there is no drug that can activate it).

Recently, however, a research report was published which suggests this “undruggable” protein is druggable, and the activator is derived from a curious source: dopamine

In today’s post, we will discuss what NURR1 is, what the new research suggests, and how this new research could be useful in the development of novel therapeutics for Parkinson’s.

Source: PPcorn

It always seems impossible until it’s done – Nelson Mandela

In 1997, when Nelson Mandela was stepping down as President of the African National Congress, some researchers in Stockholm (Sweden) published the results of a study that would have a major impact on our understanding of how to keep dopamine neurons alive.

(Yeah, I know. That is a strange segway, but some of my recent intros have dragged on a bit – so let’s just get down to business)

Dopamine neurons are of the one groups of cells in the brain that are severely affected by Parkinson’s. By the time a person begins to exhibit the movement symptoms of the condition, they will have lost 40-60% of the dopamine neurons in a region called the substantia nigra. In the image below, there are two sections of brain – cut on a horizontal plane through the midbrain at the level of the substantia nigra – one displaying a normal compliment of dopamine neurons (on the left) and the other from a person who passed away with Parkinson’s demonstrating a reduction in this cell population (on the right).

The dark pigmented dopamine neurons in the substantia nigra are reduced in the Parkinsonian brain (right). Source:Memorangapp

The researchers in Sweden had made an amazing discovery – they had identified a single gene (a specific region of DNA) that was critical to the survival of dopamine neurons. When they artificially disrupted the section of DNA where this gene lives – an action which resulted in no protein for this gene being produced – it resulted in mice being born with no midbrain dopamine neurons:

Title: Dopamine neuron agenesis in Nurr1-deficient mice
Authors: Zetterström RH, Solomin L, Jansson L, Hoffer BJ, Olson L, Perlmann T.
Journal: Science. 1997 Apr 11;276(5310):248-50.
PMID: 9092472

The researchers who conducted this study found that the mice with no NURR1 protein exhibited very little movement and did not survive long after birth. And this result was very quickly replicated by other independent research groups (Click here and here to see examples)

So what was this amazing gene called?

Nuclear receptor related 1 protein (or NURR1; it is also known as NR4A2 – nuclear receptor subfamily 4, group A, member 2)

And what is NURR1?

Continue reading “When undruggable becomes druggable” →

Gene therapy: VY-AADC01 vs AXO-Lenti-PD

~ Simon ~ 2 Comments

 

Future generations may treat conditions like Parkinson’s with DNA rather than drugs. By manipulating the DNA within a given cell, researchers can cause that cell to generate proteins that they usually do not produce.

This technique is called gene therapy, and it is currently being clinically tested in people with Parkinson’s.

Recently, one biotech firm (Voyager Therapeutics) has provided new data on an ongoing clinical trial and another company (Axovant Sciences) has announced the initiation of a clinical study.

In today’s post, we will discuss what gene therapy is, evaluate what the first company has achieved, and compare it with the clinical trial that is just starting.

 

Source: 2018.myana

At the annual American Neurology Association (ANA) meeting this year, we got an update on an ongoing clinical trial for Parkinson’s being conducted by a company called Voyager Therapeutics.

The biotech firm presented data at the meeting regarding their gene therapy approach for Parkinson’s.

What is gene therapy?

Continue reading “Gene therapy: VY-AADC01 vs AXO-Lenti-PD” →

Voyager Therapeutics update

~ Simon ~ 8 Comments

This week a biotech company called Voyager Therapeutics provided an update regarding a gene therapy approach for people with severe Parkinson’s.

Gene therapy is an experimental therapeutic approach that involves inserting new DNA into cells using a virus. The introduced DNA can help a cell to produce proteins that it usually wouldn’t  produce, and this can help to alleviate the motor features of Parkinson’s.

In today’s post we will discuss what gene therapy is, what Voyager Therapeutics is trying to do, and outline what their update reported.

There are 4 phases to the clinical trial process of testing new treatment for use in humans:

  • Phase I determines if a treatment is safe in humans (this is conducted in an ‘open label’ manner)
  • Phase II ‘double blindly’ assesses in a small cohort of subjects if the treatment is effective
  • Phase III involves randomly and blindly testing the treatment in a very large cohort of patients
  • Phase IV (often called Post Marketing Surveillance Trials) are studies conducted after the treatment has been approved for clinical use

(‘Open label’ refers to both the investigator and the participants in a study knowing what treatment is being administered; while ‘double blind’ testing refers to studies in which the participants and the investigators do not know whether the participant is receiving the active treatment or an inert control treatment until the end of the study).

Based on the successful completion of their Phase I clinical trials for their gene therapy treatment called VY-AADC (Click here to read more about this), Boston-based biotech firm Voyager Therapeutics approached the US Food and Drug Administration (FDA) with the goal of shifting their clinical trial programme into Phase II testing.

What is gene therapy?

Continue reading “Voyager Therapeutics update” →

Voyager Therapeutics: Phase I clinical trial update

~ Simon ~ 12 Comments

Today biotech company Voyager Therapeutics announced an update on their ongoing phase Ib clinical trial. The trial is evaluating the safety and tolerance of a gene therapy approach for people with advanced Parkinson’s.

Gene therapy is a technique that involves inserting new DNA into a cell using viruses. In this clinical trial, the virally delivered DNA helps the infected cell to produce dopamine in order to alleviate the motor features of Parkinson’s.

In today’s post we will discuss what gene therapy is, review the new results mentioned in the update, and look at other gene therapy approaches for Parkinson’s.


Source: Baltimoresun

Voyager Therapeutics is a clinical-stage gene therapy company that is focused on treatments for neurological conditions, such as Parkinson’s. Today the company announced an update of their ongoing Phase 1b trial of their product VY-AADC01 (Click here to see the press release).

VY-AADC01 represents a new class of treatment for Parkinson’s, as it is a form of gene therapy.

What is gene therapy?

The gene therapy involves introducing a piece of DNA into a cell which will cause the cell to produce proteins that they usually do not (either by nature or by mutation). The DNA is artificially inserted into cells and the cell’s protein producing machinery does the rest.

Source: Yourgenome

How does gene therapy work?

Continue reading “Voyager Therapeutics: Phase I clinical trial update” →

Are we getting NURR to the end of Parkinson’s disease?

~ Simon ~ 9 Comments

Nuclear receptor related 1 protein (or NURR1) is a protein that is critical to the development and survival of dopamine neurons – the cells in the brain that are affected in Parkinson’s disease.

Given the importance of this protein for the survival of these cells, a lot of research has been conducted on finding activators of NURR1.

In today’s post we will look at this research, discuss the results, and consider issues with regards to using these activators in Parkinson’s disease.

Comet Hale–Bopp. Source: Physics.smu.edu

Back in 1997, 10 days after Comet Hale–Bopp passed perihelion (April 1, 1997 – no joke; perihelion being the the point in the orbit of a comet when it is nearest to the sun) and just two days before golfer Tiger Woods won his first Masters Tournament, some researchers in Stockholm (Sweden) published the results of a study that would have a major impact on our understanding of how to keep dopamine neurons alive.

Dopamine neurons are one group of cells in the brain that are severely affected by Parkinson’s disease. By the time a person begins to exhibit the movement symptoms of the condition, they will have lost 40-60% of the dopamine neurons in a region called the substantia nigra. In the image below, there are two sections of brain – cut on a horizontal plane through the midbrain at the level of the substantia nigra – one displaying a normal compliment of dopamine neurons and the other from a person who passed away with Parkinson’s demonstrating a reduction in this cell population.

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The dark pigmented dopamine neurons in the substantia nigra are reduced in the Parkinson’s disease brain (right). Source:Memorangapp

The researchers in Sweden had made an amazing discovery – they had identified a single gene that was critical to the survival of dopamine neurons. When they artificially mutated the section of DNA where this gene lives – an action which resulted in no protein for this gene being produced – they generated genetically engineered mice with no dopamine neurons:

Title: Dopamine neuron agenesis in Nurr1-deficient mice
Authors: Zetterström RH, Solomin L, Jansson L, Hoffer BJ, Olson L, Perlmann T.
Journal: Science. 1997 Apr 11;276(5310):248-50.
PMID: 9092472

The researchers who conducted this study found that the mice with no NURR1 protein exhibited very little movement and did not survive long after birth. And this result was very quickly replicated by other research groups (Click here and here to see examples)

So what was this amazing gene called?

Continue reading “Are we getting NURR to the end of Parkinson’s disease?” →

O’mice an’ men – gang aft agley

~ Simon ~ 16 Comments

This week a group of scientists have published an article which indicates differences between mice and human beings, calling into question the use of these mice in Parkinson’s disease research.

The results could explain way mice do not get Parkinson’s disease, and they may also partly explain why humans do.

In today’s post we will outline the new research, discuss the results, and look at whether Levodopa treatment may (or may not) be a problem.

The humble lab mouse. Source: PBS

Much of our understanding of modern biology is derived from the “lower organisms”.

From yeast to snails (there is a post coming shortly on a snail model of Parkinson’s disease – I kid you not) and from flies to mice, a great deal of what we know about basic biology comes from experimentation on these creatures. So much in fact that many of our current ideas about neurodegenerative diseases result from modelling those conditions in these creatures.

Now say what you like about the ethics and morality of this approach, these organisms have been useful until now. And I say ‘until now’ because an interesting research report was released this week which may call into question much of the knowledge we have from the modelling of Parkinson’s disease is these creatures.

You see, here’s the thing: Flies don’t naturally develop Parkinson’s disease.

Nor do mice. Or snails.

Or yeast for that matter.

So we are forcing a very un-natural state upon the biology of these creatures and then studying the response/effect. Which could be giving us strange results that don’t necessarily apply to human beings. And this may explain our long history of failed clinical trials.

We work with the best tools we have, but it those tools are flawed…

What did the new research report find?

This is the study:


Title: Dopamine oxidation mediates mitochondrial and lysosomal dysfunction in Parkinson’s disease
Authors: Burbulla LF, Song P, Mazzulli JR, Zampese E, Wong YC, Jeon S, Santos DP, Blanz J, Obermaier CD, Strojny C, Savas JN, Kiskinis E, Zhuang X, Krüger R, Surmeier DJ, Krainc D
Journal: Science, 07 Sept 2017 – Early online publication
PMID: 28882997

The researchers who conducted this study began by growing dopamine neurons – a type of cell badly affected by Parkinson’s disease – from induced pluripotent stem (IPS) cells.

What are induced pluripotent stem cells?

Continue reading “O’mice an’ men – gang aft agley” →

Voyager Therapeutics: phase Ib clinical trial results

~ Simon ~ 15 Comments

 

This week a biotech company called Voyager Therapeutics announced the results of their ongoing phase Ib clinical trial. The trial is investigating a gene therapy approach for people with severe Parkinson’s disease.

Gene therapy is a technique that involves inserting new DNA into a cell using a virus. The DNA can help the cell to produce beneficial proteins that go on help to alleviate the motor features of Parkinson’s disease.

In today’s post we will discuss gene therapy, review the new results and consider what they mean for the Parkinson’s community.

Source: Joshworth

On 25th August 2012, the Voyager 1 space craft became the first human-made object to exit our solar system.

After 35 years and 11 billion miles of travel, this explorer has finally left the heliosphere (which encompasses our solar system) and it has crossed into the a region of space called the heliosheath – the boundary area that separates our solar system from interstellar space. Next stop on the journey of Voyager 1 will be the Oort cloud, which it will reach in approximately 300 years and it will take the tiny craft about 30,000 years to pass through it.

Where is Voyager 1? Source: Tampabay

Where is Voyager actually going? Well, eventually it will pass within 1 light year of a star called AC +79 3888 (also known as Gliese 445), which lies 17.6 light-years from Earth. It will achieve this goal on a Tuesday afternoon in 40,000 years time.

Gliese 445 (circled). Source: Wikipedia

Remarkably, the Gliese 445 star itself is actually coming towards us. Rather rapidly as well. It is approaching with a current velocity of 119 km/sec – nearly 7 times as fast as Voyager 1 is travelling towards it (the current speed of the craft is 38,000 mph (61,000 km/h).

Interesting, but what does any of that have to do with Parkinson’s disease?

Well closer to home, another ‘Voyager’ is also ‘going boldly where no man has gone before’ (sort of).

Continue reading “Voyager Therapeutics: phase Ib clinical trial results” →

Future of gene therapy: hAAVing amazing new tools

~ Simon ~ 5 Comments

image-20151106-16253-1rzjd0s

In this post I review recently published research describing interesting new gene therapy tools.

“Gene therapy” involved using genetics, rather than medication to treat conditions like Parkinson’s disease. By replacing faulty sections of DNA (or genes) or providing supportive genes, doctors hope to better treat certain diseases.

While we have ample knowledge regarding how to correct or insert genes effectively, the problem has always been delivery: getting the new DNA into the right types of cells while avoiding all of the other cells.

Now, researchers at the California Institute of Technology may be on the verge of solving this issue with specially engineered viruses.

gene_therapy_augmentation_yourgenome

Gene therapy. Source: yourgenome

When you get sick, the usual solution is to visit your doctor. They will prescribe a medication for you to take, and then all things going well (fingers crossed/knock on wood) you will start to feel better. It is a rather simple and straight forward process, and it has largely worked well for most of us for quite some time.

As the overall population has started to live longer, however, we have become more and more exposed to chronic conditions which require long-term treatment regimes. The “long-term” aspect of this means that some people are regularly taking medication as part of their daily lives. In many cases, these medications are taken multiple times per day.

An example of this is Levodopa (also known as Sinemet or Madopar) which is the most common treatment for the chronic condition of Parkinson’s disease. When you swallow your Levodopa pill, it is broken down in the gut, absorbed through the wall of the intestines, transported to the brain via our blood system, where it is converted into the chemical dopamine – the chemical that is lost in Parkinson’s disease. This conversion of Levodopa increases the levels of dopamine in your brain, which helps to alleviate the motor issues associated with Parkinson’s disease.

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Levodopa. Source: Drugs

This pill form of treating a disease is only a temporary solution though. People with Parkinson’s disease – like other chronic conditions – need to take multiple tablets of Levodopa every day to keep their motor features under control. And long term this approach can result in other complications, such as Levodopa-induced dyskinesias in the case of Parkinson’s.

Yeah, but is there a better approach?

Some researchers believe there is. But we are not quite there yet with the application of that approach. Let me explain:

Continue reading “Future of gene therapy: hAAVing amazing new tools” →

An Update from Voyager Therapeutics trials for Parkinson’s

~ Simon ~ 1 Comment

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In December, we highlighted the results of a phase 1 clinical trial for Parkinson’s disease being run by a company called Voyager Therapeutics (Click here for that post). In that post we also explained that the company is attempting to take a gene therapy product (VY-AADC01) to the clinic.

VY-AADC01 is a virus that is injected into a particular part of the brain (called the putamen), where it infects cells in that area and causes them to produce a lot of a particular protein, called Aromatic L-amino acid decarboxylase (or AADC). AADC is required for turning L-dopa (one of the primary treatments for Parkinson’s disease) into dopamine – which helps to ease the motor features of the condition.

Today, while most people were focused on President Trump’s inauguration, Voyager Therapeutics provided an update on their ongoing trials. Specifically, the company reported an increase in viral infection coverage of the putamen was achieved by VY-AADC01 in their third group (‘cohort’) of subjects. They infected 42% of the putamen compared to 34% in group 2 and 21% in group 1.

In the press release, the company stated:

“The five patients enrolled in Cohort 3 received similar infusion volumes of VY-AADC01 compared to Cohort 2 (up to 900 µL per putamen), but three-fold higher vector genome concentrations, representing up to a three-fold higher total dose of up to 4.5×1012 vector genomes (vg) of VY-AADC01 compared to patients in Cohort 2 (1.5 × 1012 vg).  Patients enrolled in Cohort 3 were similar in baseline characteristics to Cohort 1 and 2.  The use of real-time, intra-operative MRI-guided delivery allowed the surgical teams to visualize the delivery of VY-AADC01 and continue to achieve greater average coverage of the putamen in Cohort 3 (42%) compared to Cohort 2 (34%) with similar infusion volumes and Cohort 1 (21%) with a lower infusion volume (Figure 1).  The surgical procedure was successfully completed in all five patients.  Infusions of VY-AADC01 have been well-tolerated with no vector-related serious adverse events (SAEs) or surgical complications in Cohort 3, and all five patients were discharged from the hospital within two days following surgery.  The Phase 1b trial remains on track to deliver six-month safety, motor function, and biomarker data from Cohort 3, as well as longer-term safety and motor function data from Cohorts 1 and 2, in mid-2017.”

This update demonstrates that the company is proceeding with increased concentrations of their virus, resulting in a wider area of the putamen being infected and producing AADC. Whether this increased area of AADC producing cells results in significant improvements to motor features of Parkinson’s disease, we shall hopefully begin to find out later this year.

As always, watch this space.