Longevity & AgingBlocking RhoA Relieves Nuclear Stress and Rejuvenates Aged Blood Stem Cells in Mice
Blood-forming stem cells lose regenerative capacity with age, and this study points to nuclear mechanics as a driver. In mouse hematopoietic stem cells (HSCs), stretching of the nuclear envelope activates the enzyme cPLA2, which switches on the signaling protein RhoA. Aged HSCs have higher intrinsic nuclear envelope tension and more active RhoA, even though aged bone marrow is softer, not stiffer. Treating aged HSCs with a RhoA inhibitor reduced nuclear envelope wrinkling stress and restored a youthful chromatin pattern in nuclear imaging. According to the abstract, it also restored the heterochromatin mark H3K9me2, reduced retrotransposon activity, raised Klf4 and improved regeneration and lymphoid/myeloid balance in vivo. The work is preclinical, but it identifies a druggable mechanical pathway in stem cell aging.
