Longevity & AgingPlatelet Protein PF4 Reverses Aging in Blood Stem Cells
Researchers at University of Illinois Chicago identified Platelet Factor 4 (PF4), secreted by megakaryocytes in bone marrow, as a key regulator of hematopoietic stem cell (HSC) aging. PF4 levels drop significantly with age in both mice and humans. Mice lacking PF4 display accelerated HSC aging hallmarks: excess myeloid output, lymphopenia, DNA damage, and reduced regenerative capacity. Strikingly, administering recombinant PF4 to old mice restored youthful HSC traits including improved cell polarity, reduced DNA damage, and balanced blood lineage output. The PF4 signal is transmitted through two HSC surface receptors, LDLR and CXCR3, and double-knockout mice showed amplified aging phenotypes. Human HSCs also responded to PF4 treatment, raising translational promise for targeting age-related blood disorders.
