Biomechanical forces exert anabolic effects on osteoblasts by activation of SMAD 1/5/8 through type 1 BMP receptor

Rath, B. and Nam, J. and Deschner, J. and Schaumburger, J. and Tingart, M. and Graessel, S. and Grifka, J. and Agarwal, S. (2011) Biomechanical forces exert anabolic effects on osteoblasts by activation of SMAD 1/5/8 through type 1 BMP receptor. BIORHEOLOGY, 48 (1). pp. 37-48. ISSN 0006-355X,

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Abstract

Osteoblasts aremechanosensitive cells, which respond to biomechanical stimuli to regulate the bone structure through anabolic and catabolic gene regulation. To examine the effects of mechanical forces on the osteogenic responses through the SMAD signaling in osteoblasts, the cells were cultured in well-characterized mechanoresponsive 3-D scaffolds and exposed to 10% dynamic compressive strain (Cmp) at 1 Hz. Subsequently, SMAD phosphorylation and osteogenic gene induction was examined. Osteoblasts cultured in 3-D scaffolds exhibited increased constitutive SMAD 1/5/8 phosphorylation, as compared to monolayers cultures. This SMAD 1/5/8 phosphorylation was further upregulated after 10, 30 and 60 min in response to Cmp, exhibiting a peak activation at 30 min. No significant changes in SMAD2 phosphorylation were observed, suggesting signals generated by Cmp may not activate the Transforming Growth Factor-beta signaling cascade. Subsequently, biomechanical stimulation-induced SMAD 1/5/8 phosphorylation upregulated the expression of osteogenic genes such as Osteoprotegrin, Msx2 and Runx2. Dorsomorphin, a selective inhibitor of the bone morphogenetic protein (BMP) receptor type 1 (BMPR1), blocked Cmp-induced SMAD 1/5/8 phosphorylation, as well as Osteoprotegrin, Msx2 and Runx2 gene expression. Collectively, the present findings demonstrate that biomechanical stimulation of osteoblasts activates SMAD 1/5/8 in the BMP signaling pathway through BMPR1 and may enhance osteogenesis by upregulating SMAD-dependent osteogenic genes.

Item Type: Article
Uncontrolled Keywords: BONE MORPHOGENETIC PROTEIN-2; GENE-EXPRESSION; FLUID SHEAR; SIGNALING PATHWAYS; UP-REGULATION; CELLS; BETA; PHOSPHORYLATION; DIFFERENTIATION; OSTEOPROTEGERIN; Scaffold; mechanical signals; BMP; SMAD signaling; dorsomorphin
Subjects: 600 Technology > 610 Medical sciences Medicine
Divisions: Medicine > Lehrstuhl für Orthopädie
Depositing User: Dr. Gernot Deinzer
Date Deposited: 29 Jun 2020 08:33
Last Modified: 29 Jun 2020 08:33
URI: https://pred.uni-regensburg.de/id/eprint/21497

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