Conditional Deletion of Gremlin-1 in Cathepsin K-expressing Mature Osteoclasts Altered the Skeletal Response to Calcium Depletion in Sex-Dependent Manner.

This study assessed the novel concept that osteoclast-derived Grem1 has regulatory functions in the skeletal response to calcium stress using an osteoclastic Grem1 conditional knockout (cKO) mouse model. The calcium stress was initiated by feeding cKO mutants and wildtype (WT) littermates a calcium-deficient diet for 2 weeks. Deletion of Grem1 in mature osteoclasts did not affect developmental bone growth nor basal bone turnover.

Overexpression of miR17 ~ 92 in Myeloid Cells in Mice Increased Bone Mass Through Reduced Bone Resorption and Increased Bone Formation in Sex-Dependent Manner.

This study assessed the feasibility of miR17 ~ 92-based antiresorptive strategy by determining the effects of conditional transgenic (cTG) overexpression of miR17 ~ 92 in myeloid cells on bone and osteoclasts. Osteoclasts of male and female cTG mutant mice each showed 3- to fivefold overexpression of miR17 ~ 92 cluster genes compared to those of age- and sex-matched wildtype (WT) littermates. Male but not female cTG mutant mice had more trabecular and cortical bones as well as lower bone resorption reflected by reduction in osteoclast number and resorbing surface.