Stronger bone and better immune protection? Exercise more!

Exercise maintains a subset of bone marrow stromal cells that give rise to osteoblasts and lymphoid progenitors. CITATIONS Shen B, Tasdogan A, Ubellacker JM, et al. A mechanosensitive peri-arteriolar niche for osteogenesis lymphopoiesis. Nature. 2021;591 (7850):438–444. The health benefits exercise have been well documented publicized, although whether how improves the fitness immune system, consequently leading better protection against infections, less studied. But this is highly relevant topic in transplantation, since patients with organ transplants often suffer from variety transplant-related complications restrain their physical activities. Thus, studies area clearly potential benefit transplant patients. In recent paper Nature, initially set out investigate cell niches support adipogenesis mouse model, but discovered lymphopoiesis adult marrow. Interestingly, maintenance unique demands mechanical stimulation bone, including exercise, its targeted deletion vivo results markedly impaired progenitor development, bacterial clearance, host survival after acute infections. Stromal express leptin receptor (LepR+) are major source growth factors hematopoietic stem committed marrow, extremely heterogeneous terms functions localizations. authors created Osteolectin-mTomato knock-in (OlnmT) mice genetically mark LepR+ tomato red fluorochrome, asking osteolectin expression would resolve functionally different cells. They found Oln-mTomato+ were exclusively confined region while they conspicuously absent peri-sinusoidal area. Such enriched osteogenic genes, whereas Oln-mTomato- preferentially expressed adipogenic genes. Consequently, when stimulated differentiate, Oln-mTomato+LepR+ gave significantly more fewer adipocytes than did Oln-mTomato-LepR+ Moreover, fate mapping experiments using OlniCreERRosa26loxp-tdTomato model demonstrated similar findings, showing substantial number new developed Oln+ upon tamoxifen treatment. concluded form not fat tissues. also observed Oln- levels factor (SCF), critical conditional Scf OlniCreERScff/f reduced frequency common progenitors (CLPs), other affected, thus suggesting presence by specifically CLPs. Indeed, treatment prolonged period broadly depleted showed fractures selectively increased CLPs aging effectively cells, subsequently provided extensive evidence aged mice, could restore as niche, which then supports hosts. further stretch-induced ion channel protein PIEZO1 activities led skeletal mass. Lastly, determined plays any role clearance infections depend on T B infection Listeria (3 days treatment) lymphocyte counts periphery, was accompanied survival, compared similarly treated littermate controls. Importantly, be substantially improved exercise. speculated mechanism behind findings arterioles may particularly conducive transmitting stimuli into maintain niche. Clearly, these novel suggest improve