A family matter

Want to know what’s hot in lab research on PSP?  Or, more accurately, want to know what will be hot in a year or two?  This week, CurePSP will announce its four newest research grant awardees.  Most of the 20 competing applications, a very large crop for CurePSP, were of excellent quality and in a less competitive cycle many of them would have been funded.   A fifth and possibly a sixth application may be funded next month after CurePSP’s leaders have had a chance to discuss the use of a new, unexpected, seven-figure donation.

Since I’m driving this bus, I’ll start with the funded grant I consider the most intriguing, though it’s the smallest of the four.  For two decades, researchers at the University of Southern California have been following a Mexican-American family with PSP in 14 members over three generations.  Two of the 14 have had autopsies confirming the diagnosis.  The inheritance pattern is most likely autosomal dominance (look it up).  There are six living, affected members and another 19 who are at 50% risk because they have an affected parent or sibling.  One of the affected members has had sequencing of the gene that encodes tau (called the MAPT gene).  That revealed no mutations.  Now, John M. Ringman, PhD and his USC colleagues plan to sequence the entire genome of four affected and one unaffected family members.

It’s entirely possible that the result will be a mutation in one of the half dozen or so genes besides MAPT that have already been identified by other methods as conferring a slight risk of developing PSP.  That wouldn’t be so exciting, though it would show that one mutation in that gene suffices to cause the disease while other mutation(s) in the same gene only raise PSP risk slightly.  That would shed light on just how that gene works with respect to PSP.

A more exciting result would be if the culprit gene in this family turns out to be one that has not been previously associated with PSP.  Even though this particular mutation would clearly not be the cause of “regular” PSP, perhaps the protein that this gene encodes will prove to be part of a molecular pathway critical to the pathogenesis of PSP but not yet investigated carefully.  That could point to scads of new treatment targets for drug developers and maybe even a diagnostic test.  Very cool.

I led a project like this on Parkinson’s disease back in the 1980s and 1990s, though we didn’t have whole-genome sequencing then.  I won’t get into the details, but you can read about the big family I found and worked with here, my subsequent clinical analysis of the family here, the report of the culprit gene here, the discovery of its significance to PD in general here, the development of a diagnostic test based on the gene’s product here, the efforts to prevent PD in lab models by reducing the gene’s product here and an initial safety report on a Phase 1 human trial here.  Maybe that’s why I find Dr. Ringman’s little project so intriguing.

More on the other new grantees in the next post.

Your own one- or two-year crystal ball

You may know that for many years one of my jobs at CurePSP is to chair the grant review. Twice a year we have a deadline for researchers in either academia or the private sector to apply for up to $100,000 for work related to PSP or CBD. It’s very competitive, as we receive about 20-25 applications a year from some top research groups and fund only about 5-7 of them. We welcome purely clinical projects as well as laboratory work. The term of the grants is 1 or 2 years. Here are the 4 successful awardees from our Fall 2019 grant cycle:

Lukasz Joachimiak, The University of Texas Southwestern Medical Center, Dallas: Structural basis for tau strain conformation in CBD and PSP

In the brain, the tau protein can form an altered shape that clumps together in an aggregated form.  This study will isolate the tau protein from healthy, PSP, and CBD patient brain tissues. Specialized research tools will be applied to determine how the abnormally folded shape of tau differs from the tau from healthy brains. Understanding the fine details of how the tau protein changes from a normal shape to the different “bad” forms found in disease will provide the blueprint for designing new methods to detect and prevent these devastating diseases in patients.

David Butler, Neural Stem Cell Institute, Rensselaer, NY: Bifunctional intrabodies to lower tau

The goal of this project is to develop therapeutic agents that will prevent tau accumulation and associated death of brain cells with novel antibody-based reagents (termed intrabodies). Intrabodies are antibodies expressed within brain cells, while antibodies produced by the immune system or administered by vein do not penetrate brain cells.   These antibodies are highly selective for tau, and they have been engineered to target tau for degradation using the cell’s normal clearing process. The study’s central hypothesis is that targeted degradation of tau protein will reduce the amount of tau available to misfold and thus reduce cell death.

J. Mark Cooper, University Hospital, London, UK: The influence of TRIM11 on tau, aggregation, release, and propagation

In 2018 this research group identified the TRIM11 gene as a risk factor for PSP. This study will investigate the effects of a the protein encoded by that gene on toxic tau protein aggregation in the brain. It is believed to play a role in regulating the levels of some proteins within the cell, in particular proteins that may form aggregates. The study will use models of brain cells grown in the laboratory to focus on how changes to TRIM11 influence tau protein regulation, in particular its tendency to aggregate. These findings may help to identify potential therapeutic targets to modify PSP disease progression.

K. Matthew Scaglione, Duke University, Durham, NC: Small-molecule regulation of a protein quality-control E3 to treat PSP

The protein Hsc70 or “CHIP” accelerates the removal of tau from the brain. This project intends to identify compounds that stimulate CHIP functions.  One important such function is as an “E3” enzyme, which is an important part of one of the brain cells’ “garbage disposal” mechanisms called the ubiquitin-proteasome system (UPS).  E3 allows the UPS to recognize specific proteins for appropriate disposal.  Finding new compounds to stimulate this function is an important first step toward developing small (that is, orally dosable) molecules to slow or prevent the progression of PSP and CBD.

(If those descriptions sound like they’re not my own writing style, it because each was provided by the researchers themselves and then edited by me to fit what I think, based on little evidence, to be the technical background of this blog’s readers.)

I’ll update you on the progress of those projects once they’re publicly presented or published over the next 2 or 3 years.

A sidebar about PubMed: If you didn’t already know, you can see these, or any, researchers’ previously published work by typing a name into the search line at PubMed. Enter the last name, then the initials. To narrow it down, add a topic (like tau or neurodegenerative disease). The initial display lists papers satisfying the search terms in reverse chronological order. Clicking on one of them brings up the authors, institutions and a half-page, technical-language summary. There’s always a stack of links to related papers, including subsequent ones that cite it. Clicking an author’s name will produce a list of his/her other publications. Plus, for some articles, the whole text is available via a clickable link, sometimes for free, usually for an exorbitant fee. Have fun!