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.

Tissue engineering of a collagen-based vascular media

“…Many studies have shown a correlation between α-actin expression and the force generated by a single smooth muscle cell or fibroblast. 23,[28][29][30] We believe that the cells in our experiments are generating a greater force, but we are measuring tissue How the functional testing is reported is also important for engineered tissues and native tissues alike. Methods of reporting and differences between them make comparisons between tissues difficult if not impossible.…”

Derivation of Functional Smooth Muscle Cells from Multipotent Human Hair Follicle Mesenchymal Stem Cells

“…18,19 Since the mRNA and protein levels of aSMA were low in the bFGF-containing growth medium and high in the TGF-b1 containing differentiation medium, we examined the effect of bFGF or TGF-b1 on the ability of HFCs to generate force. To this end, HFCs were cultured in the presence of bFGF (2 ng=mL) for 7 days before they were embedded (10 6 cells=mL) in fibrin hydrogels and overlaid with the medium containing 10% FBS alone or supplemented with bFGF (2 ng=mL) or TGF-b1 (2 ng=mL).…”

“…18,19 In addition, application of bFGFcontaining collagen sponges in full-thickness wounds reduced aSMA expression and wound contraction in a rat model. 29,30 In agreement, we showed that treatment of HFCs with bFGF decreased aSMA fibers significantly and diminished the ability of these cells to contract fibrin.…”

Biological Impact of Melatonin on the Healing of Albino Rats’ Tongue Ulcer.

“…Perhaps, a potent anti-inflammatory property of melatonin is linked to its ability to act as a scavenger of exogenous and endogenous reactive oxygen species (ROS) and reactive nitrogen species (RNS) (31) During wound healing, fibroblasts differentiate into myofibroblasts, which generate large traction forces for wound closure and tissue remodeling. One of the best-characterized markers of myofibroblast phenotype is α-SMA (32) .…”