Regulator of G Protein Signaling Protein 12 (Rgs12) Controls Mouse Osteoblast Differentiation via Calcium Channel/Oscillation and Gαi-ERK Signaling

Ziqing Li, Tongjun Liu, Alyssa Gilmore, Néstor Más Gómez, Chuanyun Fu, Jormay Lim, Shuting Yang, Claire H. Mitchell, Yi ping Li, Merry J. Oursler, Shuying Yang

Research output: Contribution to journalArticle

3 Scopus citations

Abstract

Bone homeostasis intimately relies on the balance between osteoblasts (OBs) and osteoclasts (OCs). Our previous studies have revealed that regulator of G protein signaling protein 12 (Rgs12), the largest protein in the Rgs super family, is essential for osteoclastogenesis from hematopoietic cells and OC precursors. However, how Rgs12 regulates OB differentiation and function is still unknown. To understand that, we generated an OB-targeted Rgs12 conditional knockout (CKO) mice model by crossing Rgs12 fl/fl mice with Osterix (Osx)-Cre transgenic mice. We found that Rgs12 was highly expressed in both OB precursor cells (OPCs) and OBs of wild-type (WT) mice, and gradually increased during OB differentiation, whereas Rgs12-CKO mice (Osx Cre/+ ; Rgs12 fl/fl ) exhibited a dramatic decrease in both trabecular and cortical bone mass, with reduced numbers of OBs and increased apoptotic cell population. Loss of Rgs12 in OPCs in vitro significantly inhibited OB differentiation and the expression of OB marker genes, resulting in suppression of OB maturation and mineralization. Further mechanism study showed that deletion of Rgs12 in OPCs significantly inhibited guanosine triphosphatase (GTPase) activity and cyclic adenosine monophosphate (cAMP) level, and impaired Calcium (Ca 2+ ) oscillations via restraints of major Ca 2+ entry sources (extracellular Ca 2+ influx and intracellular Ca 2+ release from endoplasmic reticulum), partially contributed by the blockage of L-type Ca 2+ channel mediated Ca 2+ influx. Downstream mediator extracellular signal-related protein kinase (ERK) was found inactive in OBs of Osx Cre/+ ; Rgs12 fl/fl mice and in OPCs after Rgs12 deletion, whereas application of pertussis toxin (PTX) or overexpression of Rgs12 could rescue the defective OB differentiation via restoration of ERK phosphorylation. Our findings reveal that Rgs12 is an important regulator during osteogenesis and highlight Rgs12 as a potential therapeutic target for bone disorders.

Original languageEnglish (US)
Pages (from-to)752-764
Number of pages13
JournalJournal of Bone and Mineral Research
Volume34
Issue number4
DOIs
StatePublished - Apr 2019

Keywords

  • CALCIUM CHANNEL/OSCILLATION
  • GαI SIGNALING
  • OSTEOBLASTS
  • RGS12

ASJC Scopus subject areas

  • Endocrinology, Diabetes and Metabolism
  • Orthopedics and Sports Medicine

Fingerprint Dive into the research topics of 'Regulator of G Protein Signaling Protein 12 (Rgs12) Controls Mouse Osteoblast Differentiation via Calcium Channel/Oscillation and Gαi-ERK Signaling'. Together they form a unique fingerprint.

  • Cite this