The clustering (or aggregation) of misfolded proteins is a key feature of many neurodegenerative conditions. These aggregating proteins are collectively referred to as ‘amyloid’ proteins, and the way that they have misfolded allows many copies of these proteins to stick together.
Amyloid proteins are associated with more than 50 medical conditions (from Alzheimer’s, ALS, Huntinton’s and Parkinson’s through to rheumatoid arthritis and diabetes).
In addition to being public enemy no. 1 for their respective conditions, amyloid proteins also share another curious feature:
They glow when exposed to specific wavelengths of light (like near-infrared).
In today’s post, we will look at what we mean by ‘amyloid proteins’, what this new research found, and how this property could be extremely useful in the tracking of Parkinson’s over time.
If you have recently sent me an email, you may not have had a response. I apologise profusely for this, but I have gradually become inundated with questions and requests, and have had a hard time keeping up (in addition: family and day job take priority).
I do get some wonderfully titled emails though, which immediately grab the attention.
For example, the other day I recieved an email entitled:
“So, will my head glow in a disco?”
A brief glance at the contents confirmed suspicions that the sender was referring to this new research report:
Title: Ultraviolet–visible–near-infrared optical properties of amyloid fibrils shed light on amyloidogenesis
Authors: Pansieri J, Josserand V, Lee S-J, Rongier A, Imbert D, Sallanon MM, Kövari E, Dane TG, Vendrely C, Chaix-Pluchery O, Guidetti M, Vollaire J, Fertin A, Usson Y, Rannou P, Coll J-L, Marquette C, & Forge V
Journal: Nature Photonics, published 13th May 2019
Previously researchers have described an intrinsic ultraviolet–visible optical property to amyloid proteins.
What does that mean?
Recently a really interesting research report was published that presented several rather amazing findings.
The researchers forced dopamine-producing cells in a rodent brain to start making a protein called neuromelanin and by doing this, they witnessed the occurence of Parkinson’s-like features (motor issues, Lewy body-like structures, and cell death).
The report also suggested a method by which this outcome could be reduced or rescued.
But the amazing part is that neuromelanin was previously considered to be protective and this new finding suggests we may need to rethink that idea.
In today’s post, we will discuss what neuromelanin is, what this new report found, and how this new knowledge could be useful in the context of Parkinson’s.
Prof Heiko Braak. Source – Memim.com
This is Prof Heiko Braak.
Many years ago, he sat down and examined hundreds of postmortem brains from people with Parkinson’s.
He had collected brains from people who passed away at different stages of the condition, and was looking for any kind of pattern that might explain where and how the disease starts. His research led to what is referred to as the “Braak staging” model of Parkinson’s – a six step explanation of how the condition spreads up from the brain stem (the top of the spinal cord) and into the rest of the brain (Click here and here to read more about this).
The Braak stages of PD. Source: Nature
Braak found that certain populations of cells in the brain were more vulnerable to Parkinson’s than others, such as the dopamine neurons in a region called the substantia nigra, the noradrenergic neurons of the locus coeruleus, and the neurons of the dorsal motor nucleus of the vagus (don’t worry about what any of those names actually mean, I’m just trying to sound smart and make you think that I know what I’m taking about).
One feature that all of these populations of neurons all share in common – in addition to vulnerability to Parkinson’s – is the production of pigment called neuromelanin.
What is neuromelanin?
It is often said that Parkinson’s is a ‘distinctly human’ condition. Researchers will write in their reports that other animals do not naturally develop the features of the condition, even at late stages of life.
But how true is this statement?
Recently, some research has been published which brings into question this idea.
In today’s post, we will review these new findings and discuss how they may provide us with a means of testing both novel disease modifying therapies AND our very notion of what Parkinson’s means.
Checking his Tinder account? Source: LSE
Deep philosphical question: What makes humans unique?
Seriously, what differentiates us from other members of the animal kingdom?
Some researchers suggest that our tendency to wear clothes is a uniquely human trait.
The clothes we wear make us distinct. Source: Si-ta
But this is certainly not specific to us. While humans dress up to ‘stand out’ in a crowd, there are many species of animals that dress up to hide themselves from both predator and prey.
A good example of this is the ‘decorator crab’ (Naxia tumida; common name Little seaweed crab). These creatures spend a great deal of time dressing up, by sticking stuff (think plants and even some sedentary animals) to their exoskeleton in order to better blend into their environment. Here is a good example:
Many different kinds of insects also dress themselves up, such as Chrysopidae larva:
Dressed for success. Source: Bogleech
In fact, for most of the examples that people propose for “human unique” traits (for example, syntax, art, empathy), mother nature provides many counters (Humpback whales, bower birds, chickens – respectively).
So why is it that we think Parkinson’s is any different?
Wait a minute. Are there other animals that get Parkinson’s?
Lewy bodies are densely packed, circular clusters of protein that have traditionally been considered a characteristic feature of the Parkinsonian brain. Recently, however, evidence has been accumulating which calls into question this ‘defining feature’ of the condition.
The presence Lewy bodies in some cases of other neurological conditions (such as Alzheimer’s), and their complete absence in some cases of Parkinson’s, are leading many researchers to question their pivotal role in PD.
In today’s post, we will look at a new research report of Parkinson’s post mortem cases studies which present no Lewy bodies, and we will disucss what this might mean for our understanding of Parkinson’s and the future treatment of the condition.
Neuropathologists conducting a gross examination of a brain. Source: NBC
At present, a definitive diagnosis of Parkinson’s can only be made at the postmortem stage with an examination of the brain. Until that moment, all cases of Parkinson’s are ‘suspected’. When a neuropathologist makes an examination of the brain of a person who passed away with the clinical features of Parkinson’s, there are two characteristic hallmarks that they will be looking for in order to provide a final diagnosis of the condition:
1. The loss of specific populations of cells in the brain, such as the dopamine producing neurons in a region called the substantia nigra, which lies in an area called the midbrain (at the base of the brain/top of the brain stem). As the name suggests, the substantia nigra region is visible due to the production of a ‘substance dark’ molecule called neuromelanin in the dopamine neurons. And as you can see in the image below, the Parkinsonian brain has less dark pigmented cells in the substantia nigra region of the midbrain.
The dark pigmented dopamine neurons in the substantia nigra are reduced in the Parkinsonian brain (right). Source:Memorangapp
2. Dense, circular clusters (or aggregates) of protein within cells, which are called Lewy bodies.
A cartoon of a neuron, with the Lewy body indicated within the cell body. Source: Alzheimer’s news
A Lewy body is referred to as a cellular inclusion, as they are almost always found inside the cell body. They generally measure between 5–25 microns in diameter (5 microns is 0.005 mm) and thus they are tiny. But when compared to the neuron within which they reside they are rather large (neurons usually measures 40-100 microns in diameter).
A photo of a Lewy body inside of a neuron. Source: Neuropathology-web
Do all Parkinson’s brains have Lewy bodies?
This is a really interesting question. Welcome to the topic of this post.
Graphene is widely being believed to be one of the building blocks of the future. This revolutionary 2D material is being considered for all kinds of applications, including those of a medicinal nature.
This week researchers from the John Hopkins University School of Medicine and Seoul National University have published a report suggesting that graphene may also have applications for Parkinson’s.
The researchers found that exposing the Parkinson’s-associated protein, alpha synuclein, to graphene quantum dots not only prevented the protein from aggregating together into its toxic form, but also destroyed the mature toxic form of it.
A nano-sized silver bullet?
In today’s post, we will look at what graphene quantum dots are, review the new Parkinson’s-related results, and discuss what happens next for this new technology.
Prof Andre Geim and Prof Konstantin Novoselov. Source: Aerogelgraphene
They called them ‘Friday night experiments’.
Each week, two research scientists at the University of Manchester (UK) named Andre Geim and Konstantin Novoselov held sessions where they would conduct experiments that had little or nothing to do with their actual research.
These activities were simply an exercise in genuine curiosity.
And on one particular Friday in 2004, the two scientists conducted one of the simplest experiments that they had ever attempted – but it was one which would change the world: They took some sticky tape and applied it to a lump of graphite.
What is graphite?
This week, biotech firm Prothena published the results of their Phase I safety and tolerance clinical trial of their immunotherapy treatment called PRX002 (also known as RG7935).
Immunotherapy is a method of artificially boosting the body’s immune system to better fight a particular disease.
PRX002 is a treatment that targets a toxic form of a protein called alpha synuclein – which is believed by many to be one of the main villains in Parkinson’s.
In today’s post, we will discuss what immunotherapy is, review the results of the clinical trial, and consider what immunotherapy could mean for the Parkinson’s community.
I have previously mentioned on this website that any ‘cure for Parkinson’s’ is going to require three components:
- A disease halting mechanism
- A neuroprotective agent
- Some form of cell replacement therapy
This week we got some interesting clinical news regarding the one of these components: A disease halting mechanism.
The Phase I results of a clinical trial being conducted by a company called Prothena suggest that a new immunotherapy approach in people with Parkinson’s is both safe and well tolerated over long periods of time.
The good folks at Prothena Therapeutics. Source: Prothena
What is immunotherapy?
For a long time researchers have lacked truly disease-relevant models of Parkinson’s.
We have loaded cells with toxins to cause cell death, we have loaded cells with mutant proteins to cause cell death, we have loaded cells with… well, you get the idea. Long story short though, we have never had proper models of Parkinson’s – that is a model which present all of the cardinal features of the condition (Lewy bodies, cell loss, and motor impairment).
The various models we have available have provided us with a wealth of knowledge about the biology of how cells die and how we can protect them, which has led to numerous experimental drugs being tested in the clinic. But there has always been a linger question of ‘how disease-relevant are these models?’
This situation may be about to change.
In today’s post we will look at new research in which Japanese researchers have genetically engineered mice in which they observed the generation of Lewy bodies, the loss of dopamine neurons and motor impairments. We will look at how these mice have been generated, and what it may tell us about Parkinson’s.
Walt Disney. Source: PBS
Ok, before we start today’s post: Five interesting facts about the animator Walt Disney (1901 – 1966):
- Disney dropped out of high school at age 16 with the goal of joining the Army to help out in the war effort. He was rejected for being underage, but was able to get a job as an ambulance driver with the Red Cross in France.
- From 1928 (the birth of Mickey Mouse) until 1947, Disney himself performed the voice of Mickey.
- Mickey Mouse was originally named “Mortimer Mouse”, but it was Disney’s wife who suggested that the name Mortimer sounded too pompous (seriously, can you imagine a world with the “Mortimer Mouse show”?). She convinced Disney to change the name to Mickey (the name Mortimer was later given to one of Mickey’s rivals).
- To this day, Disney holds the record for the most individual Academy Awards and nominations. Between 1932 and 1969, he won 22 Academy Awards and was nominated 59 times (Source).
- And best of all: On his deathbed as he lay dying from lung cancer, Disney wrote the name “Kurt Russell” on a piece of paper. They were in effect his ‘last words’. But no one knows what they mean. Even Kurt is a bit perplexed by it all. He (along with many others) was a child actor contracted to the Disney company at the time, but why did Walt write Russell’s name as opposed to something more deep and meaningful (no disrespect intended towards Mr Russell).
Actor Kurt Russell. Source: Fxguide
When asked why he thought his great creation “Mickey mouse” was so popular, Walt Disney responded that “When people laugh at Mickey Mouse, it’s because he’s so human; and that is the secret of his popularity”.
Mickey Mouse. Source: Ohmy.Disney
This is a curious statement.
Curious because in biomedical research, mice are used in experiments to better understand the molecular pathways underlying basic biology and for the testing of novel therapeutics, and yet they are so NOT human.
There are major biological differences between us and them.
Not human. Source: USNews
It has been a major dilemma for the research community for some time with regards to translating novel therapies to humans, and it raises obvious ethical questions of whether we should be using mice at all for the basic research if they are so different from us. This problem is particularly apparent in the field of immunology, where the differences between ‘mice and men’ is so vast in some cases that researcher have called for moving away from mice entirely and focusing on solely human models (Click here and here for a good reads on this topic).
What does this have to do with Parkinson’s?
On Tuesday 21st December, 1824, James Parkinson passed away in his home – two days after suffering a stroke.
It was the end of an amazing and extremely productive life.
In this post about James Parkinson – the final in the series of four observing the 200th anniversary of his first observation of Parkinson’s disease – we look at what happened following his death, and reflect on his overall legacy.
St Leonard’s church in Hoxton, London – James’ church
At the end of the third post on the life of James Parkinson (Click here to read that post), the Battle of Waterloo had just occurred and James was publishing the last of his writings.
One of the last major events in the life of James Parkinson occurred in 1823, when James was awarded the Royal College of Surgeons’ first Gold Medal.
Understand that this was a big deal.
The college had established the award way back in 1802 for “distinguished labours, researches and discoveries”. But it took them a full 21 years to find anyone that they thought worthy enough to be the first recipient.
And that first recipient: one James Parkinson
This event, however, represents very nicely how the legacy of James has changed over time. While the world currently associates James Parkinson with a neurological condition that he first described in 1817, the Royal College of Surgeons awarded him their first gold medal not for any of his medical publications, but rather for his “splendid Work on Organic Remains”.
As I have written before, James was a bit of a rockstar to the geological/palaeontology community. His writings on what he called his “favourite science”, had earned him an international reputation and one has to wonder how he would feel now if he knew that his reputation lies elsewhere.
As JP aficionado Dr Cherry Lewis once wrote: history is fickle.
Here at the SoPD, we regularly talk about the ‘bad boy’ of Parkinson’s disease – a protein called Alpha Synuclein.
Twenty years ago this year, genetic variations were identified in the alpha synuclein gene that increase one’s risk of developing Parkinson’s. In addition, alpha synuclein protein was found to be present in the Lewy bodies that are found in the brains of people with Parkinson’s. Subsequently, alpha synuclein has been widely considered to be the villain in this neurodegenerative condition and it has received a lot of attention from the Parkinson’s research community.
But it is not the only protein that may be playing a role in Parkinson’s.
Today’s post is all about TAU.
I recently informed my wife that I was thinking of converting to Taoism.
She met this declaration with more of a smile than a look of shock. And I was expecting the latter, as shifting from apatheism to any form of religious belief is a bit of a leap you will appreciate.
When asked to explain myself, I suggested to her that I wanted to explore the mindfulness of what was being proposed by Lao Tzu (the supposed author of the Tao Te Ching – the founding document of Taoism).
This answer also drew a smile from her (no doubt she was thinking that Simon has done a bit of homework to make himself sound like he knows what he was talking about).
But I am genuinely curious about Taoism.
Most religions teach a philosophy and dogma which in effect defines a person. Taoism – which dates from the 4th century BCE – flips this concept on its head. It starts by teaching a single idea: The Tao (or “the way”) is indefinable. And then it follows up by suggesting that each person should discover the Tao on their own terms. Given that most people would prefer more concrete definitions in their own lives, I can appreciate that a lot of folks won’t go in for this approach.
Personally speaking, I quite like the idea that the Tao is the only principle and everything else is a just manifestation of it.
According to Taoism, salvation comes from just one source: Following the Tao.
Oh and don’t worry, I’m not going to force any more philosophical mumbo jumbo on you – Taoism is just an idea I am exploring as part of a terribly clichéd middle-life crisis I’m working my way through (my wife’s actual response to all of this was “why can’t you just be normal and go buy a motor bike or something?”).
My reason for sharing this, however, is that this introduction provides a convenient segway to what we are actually going to talk about in this post.
You see, some Parkinson’s researchers are thinking that salvation from neurodegenerative conditions like Parkinson’s will come from just one source: Following the TAU.
What is TAU?
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.
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
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.
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’).