New insights on stem cell clones and inflammation in the bones and rapamycin (UPenn)

More good news on Rapamycin, out of UPenn:

As humans age, hematopoietic stem cells—the immature precursor cells that give rise to all blood and immune cells—accumulate mutations. Some of the mutations allow these stem cells to self-renew and expand more effectively than their non-mutated counterparts. This relatively poorly understood condition, known as clonal hematopoiesis of indeterminate potential (CHIP), is detectable in more than 10% of people older than 65 and is linked to increased risks of various inflammation-related diseases.

“These mutations change the character of the progeny cells, making them more inflammatory,” says George Hajishengallis of the University of Pennsylvania’s School of Dental Medicine. “When a large fraction of your immune cells are derived from these mutant stem cells, it spells bad news for chronic inflammatory diseases.”

Now, a team led by Hajishengallis, together with collaborators at the Dresden University of Technology and the University of North Carolina at Chapel Hill (UNC), have uncovered mechanistic insights into CHIP. They also found that an FDA-approved drug for preventing organ transplant rejection, rapamycin, has the potential to block these mutant stem cells and treat CHIP-driven inflammatory bone loss diseases, such as periodontitis and arthritis. Their research is published in the journal Cell.

Full story:


Is quite a long protein with 130kDa estimating at 3.5kbp. This could be a splicing variation.

I cannot tell from the press report how they tested the protein. If they tested the protein itself or the mRNA then it could be splicing. Testing the gene is a different question, but not always reliable.