title: Effects of Hypergravity on Osteopontin Expression in Osteoblasts.
abstract: Mechanical stimuli play crucial roles in bone remodeling and resorption. Osteopontin (OPN), a marker for osteoblasts, is important in cell communication and matrix mineralization, and is known to function during mechanotransduction. Hypergravity is a convenient approach to forge mechanical stimuli on cells. It has positive effects on certain markers of osteoblast maturation, making it a possible strategy for bone tissue engineering. We investigated the effects of hypergravity on OPN expression and cell signaling in osteoblasts. Hypergravity treatment at 20 g for 24 hours upregulated OPN expression in MC3T3-E1 cells at the protein as well as mRNA level. Hypergravity promoted OPN expression by facilitating focal adhesion assembly, strengthening actin bundles, and increasing Runx2 expression. In the hypergravity-triggered OPN expression pathway, focal adhesion assembly-associated FAK phosphorylation was upstream of actin bundle assembly.
authors.affiliation: School of Biological Science and Medical Engineering, Beihang University, Beijing, China.
authors.forename: Shuai
authors.initials: S
authors.lastname: Zhou
authors.affiliation: Institute of Biomechanics and Medical Engineering, School of Aerospace Engineering, Tsinghua University, Beijing, China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Zu
authors.affiliation: Institute of Biomechanics and Medical Engineering, School of Aerospace Engineering, Tsinghua University, Beijing, China.
authors.forename: Zhenglong
authors.initials: Z
authors.lastname: Sun
authors.affiliation: School of Biological Science and Medical Engineering, Beihang University, Beijing, China.
authors.forename: Fengyuan
authors.initials: F
authors.lastname: Zhuang
authors.affiliation: Institute of Biomechanics and Medical Engineering, School of Aerospace Engineering, Tsinghua University, Beijing, China.
authors.forename: Chun
authors.initials: C
authors.lastname: Yang
mesh_terms: D000199:Actins / Q000235:genetics / Q000378:metabolism; D000818:Animals; D002454:Cell Differentiation; D002460:Cell Line; D050659:Core Binding Factor Alpha 1 Subunit / Q000819:agonists / Q000235:genetics* / Q000378:metabolism; D051417:Focal Adhesion Kinase 1 / Q000235:genetics / Q000378:metabolism; D022001:Focal Adhesions / Q000378:metabolism* / Q000648:ultrastructure; D005786:Gene Expression Regulation; D006801:Humans; D018471:Hypergravity; D040542:Mechanotransduction, Cellular / Q000235:genetics*; D051379:Mice; D010006:Osteoblasts / Q000378:metabolism* / Q000648:ultrastructure; D053495:Osteopontin / Q000819:agonists / Q000037:antagonists & inhibitors / Q000235:genetics* / Q000378:metabolism; D010766:Phosphorylation; D012333:RNA, Messenger / Q000819:agonists / Q000037:antagonists & inhibitors / Q000235:genetics* / Q000378:metabolism; D034741:RNA, Small Interfering / Q000235:genetics / Q000378:metabolism
chemical_list: D000199:Actins; D050659:Core Binding Factor Alpha 1 Subunit; D012333:RNA, Messenger; D034741:RNA, Small Interfering; C493716:Runx2 protein, mouse; C506896:Spp1 protein, mouse; D053495:Osteopontin; D051417:Focal Adhesion Kinase 1; C496051:Ptk2 protein, mouse