A FoxA2+ long-term stem cell population is necessary for growth plate cartilage regeneration after injury.

Longitudinal bone growth, achieved through endochondral ossification, is accomplished by a cartilaginous structure, the physis or growth plate, comprised of morphologically distinct zones related to chondrocyte function: resting, proliferating and hypertrophic zones. The resting zone is a stem cell-rich region that gives rise to the growth plate, and exhibits regenerative capabilities in response to injury. We discovered a FoxA2+group of long-term skeletal stem cells, situated at the top of resting zone, adjacent the secondary ossification center, distinct from the previously characterized PTHrP+ stem cells.

Abaloparatide treatment increases bone formation, bone density and bone strength without increasing bone resorption in a rat model of hindlimb unloading.

Disuse osteoporosis can result from prolonged bed rest, paralysis, casts, braces, fractures and other conditions. Abaloparatide (ABL) is a PTHrP analog that increases bone density and strength by stimulating osteogenesis with limited effects on bone resorption. We examined skeletal responses to abaloparatide in young adult male rats with normal weight-bearing and with hindlimb unloading via a pelvic harness.

Loss of protein kinase C-δ protects against LPS-induced osteolysis owing to an intrinsic defect in osteoclastic bone resorption.

Bone remodeling is intrinsically regulated by cell signaling molecules. The Protein Kinase C (PKC) family of serine/threonine kinases is involved in multiple signaling pathways including cell proliferation, differentiation, apoptosis and osteoclast biology. However, the precise involvement of individual PKC isoforms in the regulation of osteoclast formation and bone homeostasis remains unclear.