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?
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.
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.
How does gene therapy work?
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?
“Repurposing” in medicine refers to taking drugs that are already approved for the treatment of one condition and testing them to see if they are safe and effective in treating other diseases. Given that these clinically available drugs have already been shown to be safe in humans, repurposing represents a method of rapidly acquiring new potential therapeutics for a particular condition.
The antidepressant, Trazodone, has recently been proposed for repurposing to neurodegenerative conditions, such as Parkinson’s.
In today’s post we will look at what Trazodone is, why it is being considered for repurposing, and we will review the results of a new primate study that suggests it may not be ideal for the task.
Opinions. Everyone has them. Source: Creativereview
I am regularly asked by readers to give an opinion on specific drugs and supplements.
And I usually cut and paste in my standard response: I can not answer these sorts of questions as I am just a research scientist not a clinician; and even if I was a clinician, it would be unethical for me to comment as I have no idea of your medical history.
In many of these cases, there simply isn’t much proof that the drug/supplement has any effect in Parkinson’s, so it is hard to provide any kind of “opinion”. But even if there was proof, I don’t like to give opinions.
Eleven out of every ten opinions are usually wrong (except in the head of the beholder) so why would my opinion be any better? And each individual is so different, why would one particular drug/supplement work the same for everyone?
In offering an answer to “my opinion” questions, I prefer to stick to the “Just the facts, ma’am” approach and I focus solely on the research evidence that we have available (Useless pub quiz fact: this catchphrase “Just the facts, ma’am” is often credited to Detective Joe Friday from the TV series Dragnet, and yet he never actually said it during any episode! – Source).
Detective Joe Friday. Source: Wikipedia
Now, having said all of that, there is one drug in particularly that is a regular topic of inquiry (literally, not a week goes by without someone asking about): an antidepressant called Trazodone.
What is Trazodone?
In your brain there are different types of cells.
Firstly there are the neurons (the prima donnas that we believe do most of the communication of information). Next there are the microglia cells, which act as the first and main line of active immune defence in the brain. There are also oligodendrocyte, that wrap protective sheets around the branches of the neurons and help them to pass signals.
And then there are astrocytes.
These are the ‘helper cells’ which maintain a comfortable environment for the neurons and aid them in their task. Recently, researchers in California reported an curious observation in the Parkinsonian brain: some astrocytes have entered an altered ‘zombie’-like state. And this might not be such a good thing.
In today’s post, we’ll review the research and discuss what it could mean – if independently replicated – for the Parkinson’s community.
Zombies. Source: wallpapersbrowse
I don’t understand the current fascination with zombies.
There are books, movies, television shows, video games. All dealing with the popular idea of dead bodies wandering the Earth terrifying people. But why the fascination? Why does this idea have such appeal to a wide portion of the populous?
I just don’t get it.
Even more of a mystery, however, is where the modern idea of the ‘zombie’ actually came from originally.
You see, no one really knows.
Huh? What do you mean?
Some people believe that the word ‘zombie’ is derived from West African languages – ndzumbi means ‘corpse’ in the Mitsogo language of Gabon, and nzambi means the ‘spirit of a dead person’ in the Kongo language. But how did a word from the African continent become embedded in our psyche?
Others associate the idea of a zombie with Haitian slaves in the 1700s who believed that dying would let them return back to lan guinée (African Guinea) in a kind of afterlife. But apparently that freedom did not apply to situations of suicide. Rather, those who took their own life would be condemned to walk the Hispaniola plantations for eternity as an undead slave. Perhaps this was the starting point for the ‘zombie’.
More recently the word ‘zonbi’ (not a typo) appeared in the Louisiana Creole and the Haitian Creole and represented a person who is killed and was then brought to life without speech or free will.
Delightful stuff for the start of a post on Parkinson’s research, huh?
But we’re going somewhere with this.
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.
In the 1990, scientists identified some fruits that they suspected could give people Parkinson’s.
These fruit are bad, they reported.
More recently, researchers have identified chemicals in that exist in those same fruits that could potential be used to treat Parkinson’s.
These fruit are good, they announce.
In today’s post, we will explain why you should avoid eating certain members of the Annonaceae plant family and we will also look at the stream of research those plants have given rise to which could provide a novel therapy for Parkinson’s.
Guadeloupe. Source: Bluefoottravel
In the late 1990s, researchers noticed something really odd in the French West Indies.
It had a very strange distribution of Parkinsonisms.
What are Parkinsonisms?
‘Parkinsonisms’ refer to a group of neurological conditions that cause movement features similar to those observed in Parkinson’s disease, such as tremors, slow movement and stiffness. The name ‘Parkinsonisms’ is often used as an umbrella term that covers Parkinson’s disease and all of the other ‘Parkinsonisms’.
Parkinsonisms are generally divided into three groups:
- Classical idiopathic Parkinson’s disease (the spontaneous form of the condition)
- Atypical Parkinson’s (such as multiple system atrophy (MSA) and Progressive supranuclear palsy (PSP))
- Secondary Parkinson’s (which can be brought on by mini strokes (aka Vascular Parkinson’s), drugs, head trauma, etc)
Some forms of Parkinsonisms that at associated with genetic risk factors, such as juvenile onset Parkinson’s, are considered atypical. But as our understanding of the genetics risk factors increases, we may find that an increasing number of idiopathic Parkinson’s cases have an underlying genetic component (especially where there is a long family history of the condition) which could alter the structure of our list of Parkinsonisms.
So what was happening in the French West Indies?
Antidepressants are an important class of drugs in modern medicine, providing people with relief from the crippling effects of depression.
Recently, research has suggested that some of these drugs may also provide benefits to people suffering from Parkinson’s disease. But by saying this we are not talking about the depression that can sometimes be associated with this condition.
This new research suggests anti-depressants are actual providing neuroprotective benefits.
In today’s post we will discuss depression and its treatment, outline the recent research, and look at whether antidepressants could be useful for people with Parkinson’s disease.
It is estimated that 30 to 40% of people with Parkinson’s disease will suffer from some form of depression during the course of the condition, with 17% demonstrating major depression and 22% having minor depression (Click here to read more on this).
This is a very important issue for the Parkinson’s community.
Depression in Parkinson’s disease is associated with a variety of poor outcomes not only for the individuals, but also for their families/carers. These outcomes can include greater disability, less ability to care for oneself, faster disease progression, reduced cognitive performance, reduced adherence to treatment, worsening quality of life, and increased mortality. All of which causes higher levels of caregiver distress for those supporting the affected individual (Click here to read more about the impact of depression in early Parkinson’s).
What is depression?
Wikipedia defines depression as a “state of low mood and aversion to activity that can affect a person’s thoughts, behaviour, feelings, and sense of well-being” (Source). It is a common mental state that causes people to experience loss of interest or pleasure, feelings of guilt or low self-worth, disturbed sleep or appetite, low energy, and poor concentration.
Importantly, depression can vary significantly in severity, from simply causing a sense of melancholy to confining people to their beds.
What causes depression?
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’).
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.
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.
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?