title: Assessing the osteoblast transcriptome in a model of enhanced bone formation due to constitutive Gs-G protein signaling in osteoblasts.
abstract: G protein-coupled receptor (GPCR) signaling in osteoblasts (OBs) is an important regulator of bone formation. We previously described a mouse model expressing Rs1, an engineered constitutively active Gs-coupled GPCR, under the control of the 2.3 kb Col I promoter. These mice showed a dramatic age-dependent increase in trabecular bone of femurs. Here, we further evaluated the effects of enhanced Gs signaling in OBs on intramembranous bone formation by examining calvariae of 1- and 9-week-old Col1(2.3)/Rs1 mice and characterized the in vivo gene expression specifically occurring in osteoblasts with activated Gs G protein-coupled receptor signaling, at the cellular level rather than in a whole bone. Rs1 calvariae displayed a dramatic increase in bone volume with partial loss of cortical structure. By immunohistochemistry, Osterix was detected in cells throughout the inter-trabecular space while Osteocalcin was expressed predominantly in cells along bone surfaces, suggesting the role of paracrine mediators secreted from OBs driven by 2.3 kb Col I promoter could influence early OB commitment, differentiation, and/or proliferation. Gene expression analysis of calvarial OBs revealed that genes affected by Rs1 signaling include those encoding proteins important for cell differentiation, cytokines and growth factors, angiogenesis, coagulation, and energy metabolism. The set of Gs-GPCRs and other GPCRs that may contribute to the observed skeletal phenotype and candidate paracrine mediators of the effect of Gs signaling in OBs were also determined. Our results identify novel detailed in vivo cellular changes of the anabolic response of the skeleton to Gs signaling in mature OBs.
authors.affiliation: Endocrine Research Unit, Veterans Affairs Medical Center and Departments of Medicine and Physiology, University of California, San Francisco, CA, USA; Division of Endocrinology and Metabolism, Department of Medicine, Faculty of Medicine, Chulalongkorn University and King Chulalongkorn Memorial Hospital, Thai Red Cross Society, Bangkok, Thailand. Electronic address: lalita_md@yahoo.com.
authors.forename: Lalita
authors.initials: L
authors.lastname: Wattanachanya
authors.affiliation: Endocrine Research Unit, Veterans Affairs Medical Center and Departments of Medicine and Physiology, University of California, San Francisco, CA, USA. Electronic address: lipingwang05@yahoo.com.
authors.forename: Liping
authors.initials: L
authors.lastname: Wang
authors.affiliation: Endocrine Research Unit, Veterans Affairs Medical Center and Departments of Medicine and Physiology, University of California, San Francisco, CA, USA. Electronic address: susan.millard@mater.uq.edu.au.
authors.forename: Susan M
authors.initials: SM
authors.lastname: Millard
authors.affiliation: Endocrine Research Unit, Veterans Affairs Medical Center and Departments of Medicine and Physiology, University of California, San Francisco, CA, USA. Electronic address: weidar_lu@yahoo.com.
authors.forename: Wei-Dar
authors.initials: WD
authors.lastname: Lu
authors.affiliation: Endocrine Research Unit, Veterans Affairs Medical Center and Departments of Medicine and Physiology, University of California, San Francisco, CA, USA. Electronic address: dylancocarroll@gmail.com.
authors.forename: Dylan
authors.initials: D
authors.lastname: O'Carroll
authors.affiliation: Division of Endocrinology and Metabolism, Department of Medicine, University of California, San Francisco, CA, USA. Electronic address: Edward.Hsiao@ucsf.edu.
authors.forename: Edward C
authors.initials: EC
authors.lastname: Hsiao
authors.affiliation: Gladstone Institute of Cardiovascular Disease, San Francisco, CA, USA; Department of Medicine, University of California, San Francisco, CA, USA; Department of Cellular and Molecular Pharmacology, University of California, San Francisco, CA, USA. Electronic address: bconklin@gladstone.ucsf.edu.
authors.forename: Bruce R
authors.initials: BR
authors.lastname: Conklin
authors.affiliation: Endocrine Research Unit, Veterans Affairs Medical Center and Departments of Medicine and Physiology, University of California, San Francisco, CA, USA. Electronic address: Robert.Nissenson@ucsf.edu.
authors.forename: Robert A
authors.initials: RA
authors.lastname: Nissenson
mesh_terms: D000818:Animals; D001861:Bone Regeneration; D002478:Cells, Cultured; D051525:Fibroblast Growth Factor 9 / Q000235:genetics / Q000378:metabolism; D019205:GTP-Binding Protein alpha Subunits, Gs / Q000502:physiology*; D008822:Mice, Transgenic; D020411:Oligonucleotide Array Sequence Analysis; D010006:Osteoblasts / Q000378:metabolism*; D010012:Osteogenesis; D043562:Receptors, G-Protein-Coupled / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction; D012886:Skull / Q000473:pathology / Q000503:physiopathology; D000076182:Sp7 Transcription Factor; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism; D059467:Transcriptome
chemical_list: C496460:Fgf9 protein, mouse; D051525:Fibroblast Growth Factor 9; D043562:Receptors, G-Protein-Coupled; D000076182:Sp7 Transcription Factor; C479466:Sp7 protein, mouse; D014157:Transcription Factors; D019205:GTP-Binding Protein alpha Subunits, Gs
keywords: G protein coupled receptor (GPCR); Gene expression analysis; Intramembranous bone; Mouse model; Osteoblasts (OBs); Paracrine mediators