Hypergravity-induced enrichment of β1 integrin on the cell membranes of osteoblast-like cells via caveolae-dependent endocytosis

In bone cells, integrins on the cellular surface are the primary sensors of their mechanical environment. Although gravitational changes are known to affect the adhesion and functions of bone cells, whether integrins respond to hypergravity in osteoblasts remains unclear. In this work, we demonstrate that exposure to a hypergravitational environment (20 x g via centrifugation) resulted in the concentration of beta 1, but not beta 3, integrin on the cell membrane of osteoblast-like (MC3T3-E1) cells. Notably, the total expression of both integrins was unaffected by the hypergravitational environment. In addition, caveolin-dependent endocytosis was discovered to be involved in the regulation of the enrichment of 01 integrin on the cell surface after stimulation by hypergravity. These findings could aid in the improvement of our understanding of the mechanisms underlying the effects of different gravitational forces on the human body. (C) 2015 Elsevier Inc. All rights reserved.