mscs

differentiation human

Cell Stem Cell

•Adiponectin-cre marks LepR+ bone marrow SSCs, and Gli1creERT2 marks periosteal SSCs•LepR+Adipoq+ bone marrow SSCs are responsible for adult steady-state osteogenesis•LepR+Adipoq+ bone marrow SSCs are responsible for the repair of drill-hole injuries•Gli1+ periosteal SSCs are primarily responsible for the repair of bicortical fractures A fundamental question in bone biology concerns the contributions of skeletal stem/progenitor cells (SSCs) in the bone marrow versus the periosteum to bone repair. We found that SSCs in adult bone marrow can be identified based on Leprcre and Adiponectin-cre/creER expression while SSCs in adult periosteum can be identified based on Gli1creERT2 expression. Under steady-state conditions, new bone arose primarily from bone marrow SSCs. After bone injuries, both SSC populations began proliferating but made very different contributions to bone repair. Drill injuries were primarily repaired by LepR+/Adiponectin+ bone marrow SSCs. Conversely, bicortical fractures were primarily repaired by Gli1+ periosteal SSCs, though LepR+/Adiponectin+ bone marrow cells transiently formed trabecular bone at the fracture site. Gli1+ periosteal cells also regenerated LepR+ bone marrow stromal cells that expressed hematopoietic niche factors at fracture sites. Different bone injuries are thus repaired by different SSCs, with periosteal cells regenerating bone and marrow stroma after non-stabilized fractures. A fundamental question in bone biology concerns the contributions of skeletal stem/progenitor cells (SSCs) in the bone marrow versus the periosteum to bone repair. We found that SSCs in adult bone marrow can be identified based on Leprcre and Adiponectin-cre/creER expression while SSCs in adult periosteum can be identified based on Gli1creERT2 expression. Under steady-state conditions, new bone arose primarily from bone marrow SSCs. After bone injuries, both SSC populations began proliferating but made very different contributions to bone repair. Drill injuries were primarily repaired by LepR+/Adiponec...

Bone marrow and periosteal skeletal stem/progenitor cells make distinct contributions to bone maintenance and repair