Tagged: neurodegeneration

“Three hellos” for Parkinson’s

Trehalose is a small molecule – nutritionally equivalent to glucose – that helps to prevent protein from aggregating (that is, clustering together in a bad way).

Parkinson’s disease is a neurodegenerative condition that is characterised by protein aggregating, or clustering together in a bad way.

Is anyone else thinking what I’m thinking?

In today’s post we will look at what trelahose is, review some of the research has been done in the context of Parkinson’s disease, and discuss how we should be thinking about assessing this molecule clinically.


Neuropathologists examining a section of brain tissue. Source: Imperial

When a neuropathologist makes an examination of the brain of a person who passed away with Parkinson’s, there are two characteristic hallmarks that they will be looking for in order to provide a definitively postmortem diagnosis of the condition:

1.  The loss of dopamine producing neurons in a region of the brain called the substantia nigra.

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

2.  The clustering (or ‘aggregation’) of a protein called alpha synuclein. Specifically, they will be looking for dense circular aggregates of the protein within cells, which are referred to as Lewy bodies.

A Lewy body inside of a neuron. Source: Neuropathology-web

Alpha-synuclein is actually a very common protein in the brain – it makes up about 1% of the material in neurons (and understand that there are thousands of different proteins in a cell, thus 1% is a huge portion). For some reason, however, in Parkinson’s disease this protein starts to aggregate and ultimately forms into Lewy bodies:

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A cartoon of a neuron, with the Lewy body indicated within the cell body. Source: Alzheimer’s news

In addition to Lewy bodies, the neuropathologist may also see alpha synuclein clustering in other parts of affected cells. For example, aggregated alpha synuclein can be seen in the branches of cells (these clusterings are called ‘Lewy neurites‘ – see the image below where alpha synuclein has been stained brown on a section of brain from a person with Parkinson’s disease.

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Examples of Lewy neurites (indicated by arrows). Source: Wikimedia

Given these two distinctive features of the Parkinsonian brain (the loss of dopamine neurons and the aggregation of alpha synuclein), a great deal of research has focused on A.) neuroprotective agents to protect the remaining dopamine-producing neurons in the substantia nigra, and B.) compounds that stop the aggregation of alpha synuclein.

In today’s post, we will look at the research that has been conducted on one particular compounds that appears to stop the aggregation of alpha synuclein.

It is call Trehalose (pronounces ‘tray-hellos’).

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

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?

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A clever new Trk for Rasagiline

The protein Alpha Synuclein has long been considered the bad-boy of Parkinson’s disease research. Possibly one of the main villains in the whole scheme of things. 

New research suggests that it may be interfering with a neuroprotective pathway, leaving the affected cell more vulnerable to stress/toxins. But that same research has highlighted a novel beneficial feature of an old class of drugs: MAO-B inhibitors.

In today’s post we will outline the new research, discuss the results, and look at whether this new Trk warrants a re-think of MAO-B inhibitors.


The great Harry Houdini. Source: Wikipedia

I’m not sure about you, but I enjoy a good magic trick.

That exhilarating moment when you are left wondering just one thing: How do they do that?

(Seriously, at 4:40 a baguette comes out of thin air – how did he do that?)

Widely believed to have been one of the greatest magicians of all time (Source), Harry Houdini is still to this day revered among those who practise the ‘dark arts’.

Born Erik Weisz in Budapest (in 1874), Houdini arrived in the US in 1878. Fascinated with magic, in 1894, he launched his career as a professional magician and drew attention for his daring feats of escape. He renamed himself “Harry Houdini” – the first name being derived from his childhood nickname, “Ehrie,” and the last name paying homage to the great French magician Jean Eugène Robert-Houdin. In 1899, Houdini’s act caught the eye of Martin Beck, an entertainment manager, and from there the rest is history. Constantly upping the ante, his feats became bolder and more death defying.

And the crowds loved him.

From stage, he moved on to film – ultimately starting his own production company, Houdini Picture Corporation. In addition, he was a passionate debunker of psychics and mediums, his training in magic helping him to expose frauds (which turned him against his former friend Sir Arthur Conan Doyle, who believed deeply in spiritualism).

This is all very interesting, but what does any of it have to do with Parkinson’s?

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NIX-ing the PARKIN and PINK1 problem

In American slang, to ‘nix‘ something is to ‘put an end to it’.

Curiously, a protein called NIX may be about to help us put an end to Parkinson’s disease, at least in people with specific genetic mutations.

In today’s post we will look at what NIX is, outline a new discovery about it, and discuss what this new information will mean for people living with Parkinson’s disease.


Sydney harbour. Source: uk.Sydney

Before we start, I would like the reader to appreciate that I am putting trans-Tasman rivalry side here to acknowledge some really interesting research that is being conducted in Australia at the moment.

And this is really interesting.

I have previously spoken a lot about mitochondria and Parkinson’s on this website. For the uninitiated, mitochondria are the power house of each cell. They help to keep the lights on. Without them, the party is over 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 tiny bean-shaped objects within the cell. They convert nutrients 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 (some cells have thousands) and highly organised within the cell, being moved around to wherever they are needed.

Like you and I and all other things in life, however, mitochondria have a use-by date.

As mitochondria get old and worn out (or damaged) with time, the cell will recycle them via a process called mitophagy (a blending of the words mitochondria and autophagy – the waste disposal system of each cell).

What does this have to do with Parkinson’s disease?

Well, about 10% of Parkinson’s cases are associated with particular genetic variations that render people vulnerable to developing the condition. Some of these mutations are in sections of DNA (called genes) that provide the instructions for proteins that are involved in the process of mitophagy. Two genes, in particular, are the focus of a lot of Parkinson’s-related research – they are called PARKIN and PINK1.

What do PARKIN and PINK1 do?

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We need a clinical trial of broccoli. Seriously!

In a recent post, I discussed research looking at foods that can influence the progression of Parkinson’s (see that post here). I am regularly asked about the topic of food and will endeavour to highlight more research along this line in future post.

In accordance with that statement, today we are going to discuss Cruciferous vegetables, and why we need a clinical trial of broccoli.

I’m not kidding.

There is growing research that a key component of broccoli and other cruciferous vegetables – called Glucoraphanin – could have beneficial effects on Parkinson’s disease. In today’s post, we will discuss what Glucoraphanin is, look at the research that has been conducted and consider why a clinical trial of broccoli would be a good thing for Parkinson’s disease.


 

Cruciferous vegetables. Source: Diagnosisdiet

Like most kids, when I was young I hated broccoli.

Man, I hated it. With such a passion!

Usually they were boiled or steamed to the point at which they have little or no nutritional value, and they largely became mush upon contact with my fork.

The stuff of my childhood nightmares. Source: Modernpaleo

As I have matured (my wife might debate that statement), my opinion has changed and I have come to appreciate broccoli. Our relationship has definitely improved.

In fact, I have developed a deep appreciation for all cruciferous vegetables.

And yeah, I know what you are going to ask:

What are cruciferous vegetables?

Cruciferous vegetables are vegetables of the Brassicaceae family (also called Cruciferae). They are a family of flowering plants commonly known as the mustards, the crucifers, or simply the cabbage family. They include cauliflower, cabbage, garden cress, bok choy, broccoli, brussels sprouts and similar green leaf vegetables.

Cruciferous vegetables. Source: Thetherapyshare

So what have Cruciferous vegetables got to do with Parkinson’s?

Well, it’s not the vegetables as such that are important. Rather, it is a particular chemical that this family of plants share – called Glucoraphanin – that is key.

What is Glucoraphanin?

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O’mice an’ men – gang aft agley

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?

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The next killer APP: LRRK2 inhibitors?

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In Silicon valley (California), everyone is always looking for the “next killer app” – the piece of software (or application) that is going to change the world. The revolutionary next step that will solve all of our problems.

The title of today’s post is a play on the words ‘killer app’, but the ‘app’ part doesn’t refer to the word application. Rather it relates to the Alzheimer’s disease-related protein Amyloid Precursor Protein (or APP). Recently new research has been published suggesting that APP is interacting with a Parkinson’s disease-related protein called Leucine-rich repeat kinase 2 (or LRRK2).

The outcome of that interaction can have negative consequences though.

In today’s post we will discuss what is known about both proteins, what the new research suggests and what it could mean for Parkinson’s disease.


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Seattle. Source: Thousandwonders

In the mid 1980’s James Leverenz and Mark Sumi of the University of Washington School of Medicine (Seattle) made a curious observation.

After noting the high number of people with Alzheimer’s disease that often displayed some of the clinical features of Parkinson’s disease, they decided to examined the postmortem brains of 40 people who had passed away with pathologically confirmed Alzheimer’s disease – that is, an analysis of their brains confirmed that they had Alzheimer’s.

What the two researchers found shocked them:

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Title: Parkinson’s disease in patients with Alzheimer’s disease.
Authors: Leverenz J, Sumi SM.
Journal: Arch Neurol. 1986 Jul;43(7):662-4.
PMID: 3729742

Of the 40 Alzheimer’s disease brains that they looked at nearly half of them (18 cases) had either dopamine cell loss or Lewy bodies – the characteristic features of Parkinsonian brain – in a region called the substantia nigra (where the dopamine neurons are located). They next went back and reviewed the clinical records of these cases and found that rigidity, with or without tremor, had been reported in 13 of those patients. According to their analysis 11 of those patients had the pathologic changes that warranted a diagnosis of Parkinson’s disease.

And the most surprising aspect of this research report: Almost all of the follow up studies, conducted by independent investigators found exactly the same thing!

It is now generally agreed by neuropathologists (the folks who analyse sections of brain for a living) that 20% to 50% of cases of Alzheimer’s disease have the characteristic round, cellular inclusions that we call Lewy bodies which are typically associated with Parkinson disease. In fact, in one analysis of 145 Alzheimer’s brains, 88 (that is 60%!) had chemically verified Lewy bodies (Click here to read more about that study).

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

Oh, and if you are wondering whether this is just a one way street, the answer is “No sir, this phenomenon works both ways”: the features of the Alzheimer’s brain (such as the clustering of a protein called beta-amyloid) are also found in many cases of pathologically confirmed Parkinson’s disease (Click here and here to read more about this).

So what are you saying? Alzheimer’s and Parkinson’s disease are the same thing???

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Nilotinib: the other phase II trial

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In October 2015, researchers from Georgetown University announced the results of a small clinical trial that got the Parkinson’s community very excited. The study involved a cancer drug called Nilotinib, and the results were rather spectacular.

What happened next, however, was a bizarre sequence of disagreements over exactly what should happen next and who should be taking the drug forward. This caused delays to subsequent clinical trials and confusion for the entire Parkinson’s community who were so keenly awaiting fresh news about the drug.

Earlier this year, Georgetown University announced their own follow up phase II clinical trial and this week a second phase II clinical trial funded by a group led by the Michael J Fox foundation was initiated.

In todays post we will look at what Nilotinib is, how it apparently works for Parkinson’s disease, what is planned with the new trial, and how it differs from the  ongoing Georgetown Phase II trial.


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The FDA. Source: Vaporb2b

This week the U.S. Food and Drug Administration (FDA) has given approval for a multi-centre, double-blind, randomised, placebo-controlled Phase IIa clinical trial to be conducted, testing the safety and tolerability of Nilotinib (Tasigna) in Parkinson’s disease.

This is exciting and welcomed news.

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).

What does any that mean?

Basically, it is the drug that is used to treat a type of blood cancer (leukemia) when the other drugs have failed. It was approved for treating this cancer by the FDA in 2007.

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Higher socioeconomic status jobs

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People with high socioeconomic status jobs are believed to be better off in life.

New research published last week by the Centre for Disease Control, however, suggests that this may not be the case with regards to one’s risk of developing Parkinson’s disease.

In today’s post we will review the research and discuss what it means for our understanding of Parkinson’s disease.


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The impact of socioeconomic status. Source: Medicalxpress

In 2013, a group of researchers at Carnegie Mellon University found a rather astonishing but very interesting association:

Children from lower socioeconomic status have shorter telomeres as adults.

Strange, right?

Yeah, wow, strange… sorry, but what are telomeres?

Do you remember how all of your DNA is wound up tightly into 23 pairs of chromosomes? Well, telomeres are at the very ends of each of those chromosomes. They are literally the cap on each end. The name is derived from the Greek words ‘telos‘ meaning “end”, and ‘merοs‘ meaning “part”.

Telomeres are regions of repetitive nucleotide sequences (think the As, Gs, Ts, & Cs that make up your DNA) at each end of a chromosome. Their purpose seems to involve protecting the end of each chromosome from deteriorating or fusing with neighbouring chromosomes. Researchers also use their length is a marker of ageing because every time a cell divides, the telomeres on each chromosome gradually get shorter.

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The Llama-nation of Parkinson’s disease

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The clustering of a protein called alpha synuclein is one of the cardinal features of the brain of a person with Parkinson’s disease.

Recently published research has demonstrated that tiny antibodies (called nanobodies) derived from llamas (yes, llamas) are very effective at reducing this clustering of alpha synuclein in cell culture models of Parkinson’s disease. 

In today’s post, we will discuss the science, review the research and consider what it could all mean for Parkinson’s disease.


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Llama. Source: Imagesanimals

Ok, I confess: This post has been partly written purely because I really like llamas. And I’m not ashamed to admit it either.

I mean, look at them! They are fantastic:

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Source: Vogue

Very cute. But what does this have to do with Parkinson’s disease?

Indeed. Let’s get down to business.

This post has also been written because llamas have a very interesting biological characteristic that is now being exploited in many areas of medical research, including for Parkinson’s disease.

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