Ptbp1: “One and done”(?)

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Recently a lot of media attention has been focused on a new study that reported the replacement of lost dopamine neurons in a mouse model of Parkinson’s, which resulted in the correction the associated behavioural/motor issues.

The researchers involved achieved this amazing feat by simply reducing a single protein in a special type of helper cell in the brain, called astrocytes. By lowering the levels of the protein, they were able to transform the astrocytes into dopamine neurons.

Intriguingly, the study represented independent replication of a previous study that demonstrated a similar result – transformation of astrocytes inside a mouse brain into dopamine neurons by reducing a single protein.

The protein in both studies is called Ptbp1, and in today’s post we will discuss what this protein does, what the new study found, and what the implications of this work could be.

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Source: Howtogeek

Earlier this year, I stated in my 2020 wish list for Parkinson’s research (Click here to read that post) that one of the big themes I was hoping to see more of was further research on regenerative approaches for the condition.

We have discussed this a few times, but any “curative” treatment for Parkinson’s will require 3 components:

  1. A disease halting mechanism – to slow/stop the progression of the disease
  2. A neuroprotective agent – to protect the remaining cells & provide a nurturing environment for,
  3. Some form of restorative/regenerative therapy – replacing what has been lost

Now the encouraging news is that if you look at the SoPD “The Road Ahead: 2020” post, you will see that there is a great deal of research being conducted on all three of these components at the clinical stage (in addition to vast amounts of work on the preclinical level).

But it is fair to say that the bulk of the clinical research being conducted on restorative therapy for Parkinson’s is centred around the transplantation of stem cell-derived dopamine neurons to replace the cells that have been lost in Parkinson’s (click here to read a recent SoPD post on this topic).

Embryonic stem cells in a petridish. Source: Wikipedia

In my wish list for 2020, I was hoping to see regenerative approaches beyond the well trodden path of cell transplantation (growing cells in culture and then injecting them into the brain).

Dopamine neurons (green) in cell culture. Source: Axolbio

Rather, I was hoping to see more research on new regenerative approaches that target/manipulate endogenous pathways in the brain – forcing changes within the central nervous system itself.

I didn’t have high expectations in this department, but I have to admit that now I have been pleasantly surprised by the number of research reports that have been published thus far this year highlighting novel regenerative approaches. We have discussed several of them here on the SoPD already (Click here and here for examples), and today we are going to review another which was recently published in the prestigious scientific journal Nature.

This is what all the news papers have been talking about?

Indeed. There has been a lot of media attention focused on this research report.

So what does the new study report?

Continue reading “Ptbp1: “One and done”(?)”

CasRx Reprogramming

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Parkinson’s is a neurodegenerative condition – this means that certain cells in the brain are being lost. Restorative therapies are those focused on replacing the lost cells in the hope that the new cells will be able to take up the lost function.

Tremendous efforts are being made in cell transplantation programs for Parkinson’s. But this month scientists have published a new research report proposing a novel method of changing the fate of cells already in the brain (removing the need to introduce new cells).

Their approach involves new technology and remarkably only requires the manipulation of a single protein.

In today’s post, we will explore the growing world of in vivo reprogramming, review the new research report, and discuss where in vivo reprogramming could go next.

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Changing cell fates. Source: MDPI

In vivo reprogramming of cells is a red hot topic in restorative research at the moment. The ability to change the fate of mature cells inside of an organism represents a ‘holy grail’-like goal for regenerative medicine.

Rather than transplanting ‘foreign’/external cells into the body (and having to deal with an immune system response), in vivo cellular reprogramming offers the possibility of simply changing the fate of a cell that is already present inside the body. And there are a lot of research groups around the world now exploring various methods of achieving this goal.

We have discussed the background research associated with in vivo cellular reprogramming for Parkinson’s in a previous SoPD post (Click here to read that post).

In today’s post, we are going to discuss a new research report that was published this month on this topic:

Title: Glia-to-Neuron Conversion by CRISPR-CasRx Alleviates Symptoms of Neurological Disease in Mice.
Authors: Zhou H, Su J, Hu X, Zhou C, Li H, Chen Z, Xiao Q, Wang B, Wu W, Sun Y, Zhou Y, Tang C, Liu F, Wang L, Feng C, Liu M, Li S, Zhang Y, Xu H, Yao H, Shi L, Yang H.
Journal: Cell. 2020 Apr 1. pii: S0092-8674(20)30286-5. [Epub ahead of print]
PMID: 32272060

In this study, the researchers used a new technology (called CRISPR-CasRx) to reduce levels of a single protein, and the reduction of this protein appears to have aided the conversion of cells in the brains of mice to become dopamine neurons – the population of cells that are severely affected in Parkinson’s.

What is CRISPR-CasRx?

Continue reading “CasRx Reprogramming”