Sex-Dependent, Osteoblast Stage-Specific Effects of Progesterone Receptor on Bone Acquisition

Zhendong A. Zhong, Alexander Kot, Yu An E. Lay, Hongliang Zhang, Junjing Jia, Nancy E Lane, Wei Yao

Research output: Contribution to journalArticle

4 Scopus citations

Abstract

The role of the progesterone receptor (PR) in the regulation of sexual dimorphism in bone has yet to be determined. Here we utilized genetic fate mapping and Western blotting to demonstrate age-dependent PR expression in the mouse femoral metaphysis and diaphysis. To define sex-dependent and osteoblast stage–specific effects of PR on bone acquisition, we selectively deleted PR at different stages of osteoblast differentiation. We found that when Prx1-Cre mice were crossed with PR floxed mice to generate a mesenchymal stem cell (MSC) conditional KO model (Prx1; PRcKO), the mutant mice developed greater trabecular bone volume with higher mineral apposition rate and bone formation. This may be explained by increased number of MSCs and greater osteogenic potential, particularly in males. Age-related trabecular bone loss was similar between the Prx1; PRcKO mice and their WT littermates in both sexes. Hormone deficiency during the period of rapid bone growth induced rapid trabecular bone loss in both the WT and the Prx1; PRcKO mice in both sexes. No differences in trabecular bone mass was observed when PR was deleted in mature osteoblasts using osteocalcin-Cre (Bglap-Cre). Also, there were no differences in cortical bone mass in all three PRcKO mice. In conclusion, PR inactivation in early osteoprogenitor cells but not in mature osteoblasts influenced trabecular bone accrual in a sex-dependent manner. PR deletion in osteoblast lineage cells did not affect cortical bone mass.

Original languageEnglish (US)
Pages (from-to)1841-1852
Number of pages12
JournalJournal of Bone and Mineral Research
Volume32
Issue number9
DOIs
StatePublished - Sep 1 2017

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Keywords

  • BONE ACCRUAL
  • CONDITIONAL GENE KNOCKOUT
  • MESENCHYMAL STROMAL CELLS
  • OSTEOBLASTS
  • OSTEOCYTES
  • PROGESTERONE RECEPTOR

ASJC Scopus subject areas

  • Endocrinology, Diabetes and Metabolism
  • Orthopedics and Sports Medicine

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