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Pharmacologic inhibition of the TGF-beta type I receptor kinase has anabolic and anti-catabolic effects on bone.

ABSTRACT: During development, growth factors and hormones cooperate to establish the unique sizes, shapes and material properties of individual bones. Among these, TGF-beta has been shown to developmentally regulate bone mass and bone matrix properties. However, the mechanisms that control postnatal skeletal integrity in a dynamic biological and mechanical environment are distinct from those that regulate bone development. In addition, despite advances in understanding the roles of TGF-beta signaling in osteoblasts and osteoclasts, the net effects of altered postnatal TGF-beta signaling on bone remain unclear. To examine the role of TGF-beta in the maintenance of the postnatal skeleton, we evaluated the effects of pharmacological inhibition of the TGF-beta type I receptor (TbetaRI) kinase on bone mass, architecture and material properties. Inhibition of TbetaRI function increased bone mass and multiple aspects of bone quality, including trabecular bone architecture and macro-mechanical behavior of vertebral bone. TbetaRI inhibitors achieved these effects by increasing osteoblast differentiation and bone formation, while reducing osteoclast differentiation and bone resorption. Furthermore, they induced the expression of Runx2 and EphB4, which promote osteoblast differentiation, and ephrinB2, which antagonizes osteoclast differentiation. Through these anabolic and anti-catabolic effects, TbetaRI inhibitors coordinate changes in multiple bone parameters, including bone mass, architecture, matrix mineral concentration and material properties, that collectively increase bone fracture resistance. Therefore, TbetaRI inhibitors may be effective in treating conditions of skeletal fragility.

SUBMITTER: Mohammad KS

PROVIDER: S-EPMC2666804 | biostudies-literature | 2009

REPOSITORIES: biostudies-literature

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Pharmacologic inhibition of the TGF-beta type I receptor kinase has anabolic and anti-catabolic effects on bone.

Mohammad Khalid S KS Chen Carol G CG Balooch Guive G Stebbins Elizabeth E McKenna C Ryan CR Davis Holly H Niewolna Maria M Peng Xiang Hong XH Nguyen Daniel H N DH Ionova-Martin Sophi S SS Bracey John W JW Hogue William R WR Wong Darren H DH Ritchie Robert O RO Suva Larry J LJ Derynck Rik R Guise Theresa A TA Alliston Tamara T

PloS one 20080416 4

During development, growth factors and hormones cooperate to establish the unique sizes, shapes and material properties of individual bones. Among these, TGF-beta has been shown to developmentally regulate bone mass and bone matrix properties. However, the mechanisms that control postnatal skeletal integrity in a dynamic biological and mechanical environment are distinct from those that regulate bone development. In addition, despite advances in understanding the roles of TGF-beta signaling in o ...[more]

PMID: 19357790

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Project description:Histone deacetylase 4 (Hdac4) is known to control chondrocyte hypertrophy and bone formation. We have previously shown that parathyroid hormone (PTH) regulates many aspects of Hdac4 function in osteoblastic cells in vitro; however, in vivo confirmation was previously precluded by preweaning lethality of the Hdac4-deficient mice. To analyze the function of Hdac4 in bone in mature animals, we generated mice with osteoblast lineage-specific knockout of Hdac4 (Hdac4ob-/- ) by crossing transgenic mice expressing Cre recombinase under the control of a 2.3-kb fragment of the Col1a1 promoter with mice bearing loxP-Hdac4. The Hdac4ob-/- mice survive to adulthood and developed a mild skeletal phenotype. At age 12 weeks, they had short, irregularly shaped and stiff tails due to smaller tail vertebrae, with almost no growth plates. The tibial growth plate zone was also thinned, and Mmp13 and Sost mRNAs were increased in the distal femurs of Hdac4ob-/- mice. Immunohistochemistry showed that sclerostin was elevated in Hdac4ob-/- mice, suggesting that Hdac4 inhibits its gene and protein expression. To determine the effect of PTH in these mice, hPTH (1-34) or saline were delivered for 14 days with subcutaneously implanted devices in 8-week-old female Hdac4ob-/- and wild-type (Hdac4fl/fl ) mice. Serum CTX, a marker of bone resorption, was increased in Hdac4ob-/- mice with or without PTH treatment. Tibial cortical bone volume/total volume (BV/TV), cortical thickness (Ct.Th), and relative cortical area (RCA) were decreased in Hdac4ob-/- mice, but PTH caused no further decrease in Hdac4ob-/- mice. Tibial trabecular BV/TV and thickness were not changed significantly in Hdac4ob-/- mice but decreased with PTH treatment. These results indicate that Hdac4 inhibits bone resorption and has anabolic effects via inhibiting Mmp13 and Sost/sclerostin expression. Hdac4 influences cortical bone mass and thickness and knockout of Hdac4 prevents the catabolic effect of PTH in cortical bone. © 2018 American Society for Bone and Mineral Research.

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Dataset Information

Pharmacologic inhibition of the TGF-beta type I receptor kinase has anabolic and anti-catabolic effects on bone.

Publications

Pharmacologic inhibition of the TGF-beta type I receptor kinase has anabolic and anti-catabolic effects on bone.

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