title: Alpha-smooth muscle actin expression enhances cell traction force.
abstract: Using an established corneal stromal cell differentiation model, we manipulated alpha-smooth muscle actin (alpha-SMA) protein expression levels in fibroblasts by treating them with TGF-beta1, bFGF, TGF-beta type I receptor inhibitor (SB-431542), and siRNA against alpha-SMA. The corresponding cell traction forces (CTFs) were determined by cell traction force microscopy. With all these treatments, we found that alpha-SMA is not required for CTF induction, but its expression upregulates CTF. This upregulation involves the modification of stress fibers but does not appear to relate to non-muscle myosin II expression or beta-actin expression. Moreover, there exists a linear relationship between alpha-SMA protein expression level and CTF magnitude. Finally, CTFs were found to vary among a population of myofibroblasts, suggesting that alpha-SMA protein expression levels of individual cells also vary.
authors.affiliation: Department of Orthopaedic Surgery, MechanoBiology Laboratory, University of Pittsburgh, Pennsylvania 15213, USA.
authors.forename: Jianxin
authors.initials: J
authors.lastname: Chen
authors.forename: Hongxia
authors.initials: H
authors.lastname: Li
authors.forename: Nirmala
authors.initials: N
authors.lastname: SundarRaj
authors.forename: James H-C
authors.initials: JH
authors.lastname: Wang
mesh_terms: D000199:Actins / Q000096:biosynthesis* / Q000235:genetics / Q000378:metabolism / Q000502:physiology; D000818:Animals; D001549:Benzamides / Q000494:pharmacology; D002454:Cell Differentiation / Q000187:drug effects / Q000502:physiology; D003319:Corneal Stroma / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism*; D004149:Dioxoles / Q000494:pharmacology; D016222:Fibroblast Growth Factor 2 / Q000494:pharmacology; D040542:Mechanotransduction, Cellular; D009130:Muscle, Smooth / Q000378:metabolism* / Q000502:physiology; D024462:Myosin Type II / Q000096:biosynthesis / Q000378:metabolism; D034741:RNA, Small Interfering / Q000235:genetics; D011817:Rabbits; D013314:Stress, Mechanical; D017154:Stromal Cells / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D053773:Transforming Growth Factor beta1 / Q000494:pharmacology
chemical_list: C459179:4-(5-benzo(1,3)dioxol-5-yl-4-pyridin-2-yl-1H-imidazol-2-yl)benzamide; D000199:Actins; D001549:Benzamides; D004149:Dioxoles; D034741:RNA, Small Interfering; D053773:Transforming Growth Factor beta1; D016222:Fibroblast Growth Factor 2; D024462:Myosin Type II