The cooperative effects of micro-grooved topography and TGF-β1 on the vascular smooth muscle cell contractile protein expression of the mesenchymal stem cells

Abstract

Cell morphological changes induced by micro-grooved topography have been shown to be an important regulator of smooth muscle (SM) differentiation of mesenchymal stem cells (MSCs). In addition to the micro-grooved topography, transforming growth factor-β₁ (TGF-β₁) can also modulate MSCs differentiation towards smooth muscle cells (SMCs) through alterations in cell morphological characteristics. Thus, it can be hypothesized that substrate topography and TGF-β₁ may interact to facilitate differentiation of MSCs into SMCs. In this study, we investigated the time-course cooperative effects of substrate topography and TGF-β₁ in the regulation of SM differentiation of human MSCs. Western blotting, followed by image analysis, was performed to assess the protein expression of α-actin, h1-calponin and gelsolin. Three-way analysis of variance was employed to investigate the main effect of each independent variable, i.e. TGF-β₁ conditioning, substrate topography and culture time, along with the interactions of these variables. Each of TGF-β₁, substrate topography and culture time significantly affected the protein expression of α-actin, h1-calponin and gelsolin. Overall, TGF-β₁ conditioning of the cells and culturing the cells on the micro-grooved substrate resulted in greater protein expression of α-actin and h1-calponin, and lesser protein expression of gelsolin. In addition to the isolated effects of the variables, treatment type interacted with substrate topography and culture time to regulate the expression of the above-mentioned proteins. This study indicated the feasibility of promoting SM differentiation of human MSCs by simultaneous recruitment of micro-grooved topography and TGF-β₁. The findings could be of assistance when effective utilization of chemo-physical cues is needed to achieve functional SMC-like MSCs in vitro.

Keywords: Differentiation; Immunoblotting analysis; Mesenchymal stem cells; Micro-grooved topography; Smooth muscle cells; TGF-β(1).