What are pericytes? What about brain pericytes? How are they different than brain parasites?
Pericytes on the brain
Someone once asked me my favorite type of cell. As a cell biologist, I easily can’t pick just one. It’s like asking a parent to pick their favorite child. However, I will say that pericytes and microglia (I’ve got a recommended papers on both today) are perhaps the cell types I most want to learn more about right at this moment.
Pericytes are unique cells associated with blood vessels. They seem to perform a variety of functions related to blood vessel functions. Pericytes may also have stem cell-like properties. For instance, if a small region of a blood vessel is damaged, it is thought that a pericyte in that region may respond by dividing and becoming other blood cell types like endothelial or smooth muscle cells. This new paper, Increased luminal pressure in brain capillaries drives TRPC3-dependent depolarization and constriction of transitional pericytes, in Science Signaling suggests one way in which these cool cells are regulated and how they function.
Nature: FDA and others should rush cell therapy approvals
Don’t rush promising stem-cell therapies, Nature. This editorial from the journal is subtitled: “Potential treatments need to be subject to the highest standards of safety and efficacy.” I hadn’t seen this opinion piece that built off the two Nature papers on stem cells for Parkinson’s disease that I wrote about at STAT News. The editorial ends: “Regulators around the world must not put that promise at risk by rushing the final stage of the process.” Here in the U.S. we’re likely to see rushed approvals and dropped standards over the next 3-4 years with our new FDA.
Banning hESC research
A dangerous new push to ban embryonic stem cell research funding is gaining momentum, STAT News. This is my latest column over at STAT. If you hadn’t heard, a group of GOP lawmakers sent a letter to Trump asking him to ban hESC research funding. There’s a solid chance he’ll do it. Project 2025 also wants a ban on that and other research. Both the GOP letter and what’s in Project 2025 are misleading about stem cells and hype adult stem cells. Lots of cheerleading about perinatal cells in these anti-hESC writings too. I’m still waiting for the new version of the FDA to approve perinatal stem cells that aren’t ready for prime time or just define them as no longer drugs.
More recommended reads
- Engineered microglia show promise for treating Alzheimer’s and other brain diseases UC Irvine team develop cell-based platform for brain-wide delivery of therapeutic proteins, UC Irvine. There’s great interest in the idea of stem cells for dementia more generally, but there haven’t been many strong signals from robust clinical trials in this area. Still, there has been some exciting preclinical research. Related to this UC Irvine news piece, here’s the Cell Stem Cell paper it discusses: Harnessing human iPSC-microglia for CNS-wide delivery of disease-modifying proteins. I like the idea of using microglia as tools. From the paper: “To determine whether human induced pluripotent stem cell (iPSC)-microglia (iMG) could enable brain-wide and pathology-responsive delivery of therapeutic cargo, we utilized CRISPR gene editing to engineer iMG to express the Aβ-degrading enzyme neprilysin under control of the plaque-responsive promoter, CD9. To further determine whether increased engraftment enhances efficacy, we utilized a CSF1R-inhibitor resistance approach. Interestingly, both localized and brain-wide engraftment in Alzheimer’s disease (AD) mice reduced multiple biochemical measures of pathology.” Some positive effects depended on the extent of engraftment.
- Humans heal much slower than other mammals, The Week. Could our weaker ability to heal be related to stem cells?
- CDK4 loss-of-function mutations cause microcephaly and short stature, G&D. One of my main projects as a postdoc was a conditional knockout of N-myc in mice, where we found it caused microcephaly. Shortly after that it was found that MYCN mutations in humans also cause microcephaly. The new results with CDK4 make sense given its ties to the MYC family including MYCN.