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Title: Assessing the osteoblast transcriptome in a model of enhanced bone formation due to constitutive G{sub s}–G protein signaling in osteoblasts

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 G{sub s}-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 G{sub s} 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 G{sub s} 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 ofmore » G{sub s}-GPCRs and other GPCRs that may contribute to the observed skeletal phenotype and candidate paracrine mediators of the effect of G{sub s} signaling in OBs were also determined. Our results identify novel detailed in vivo cellular changes of the anabolic response of the skeleton to G{sub s} signaling in mature OBs. - Highlights: • OB expression of an engineered G{sub s}-coupled receptor dramatically increases bone mass. • We investigated the changes in gene expression in vivo in enhanced OB G{sub s} signaling. • Genes in cell cycle and transcription were increased in enhanced OB G{sub s} signaling. • GPCRs and paracrine mediators of the effect of G{sub s} signaling in OBs were determined.« less
Authors:
 [1] ;  [2] ;  [1] ;  [1] ;  [1] ;  [1] ;  [3] ;  [4] ;  [5] ;  [5] ;  [1]
  1. Endocrine Research Unit, Veterans Affairs Medical Center and Departments of Medicine and Physiology, University of California, San Francisco, CA (United States)
  2. (Thailand)
  3. Division of Endocrinology and Metabolism, Department of Medicine, University of California, San Francisco, CA (United States)
  4. Gladstone Institute of Cardiovascular Disease, San Francisco, CA (United States)
  5. (United States)
Publication Date:
OSTI Identifier:
22462283
Resource Type:
Journal Article
Resource Relation:
Journal Name: Experimental Cell Research; Journal Volume: 333; Journal Issue: 2; Other Information: Copyright (c) 2015 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
60 APPLIED LIFE SCIENCES; ACID PHOSPHATASE; AGE DEPENDENCE; AMP; ANGIOGENESIS; BONE MARROW; CELL CYCLE; CELL DIFFERENTIATION; COMPUTERIZED TOMOGRAPHY; CONNECTIVE TISSUE CELLS; CULTURE MEDIA; FEMUR; FLUORESCENCE; FOURIER TRANSFORMATION; GENES; GTP-ASES; IN VIVO; LYMPHOKINES; METABOLISM; MICE; PHENOTYPE; POLYMERASE CHAIN REACTION; RECEPTORS; SYNCHROTRON RADIATION; TRABECULAR BONE; TRANSCRIPTION