Zhu Yi, He Li, Qu Jing, Zhou Yong
1Division of Pulmonary,Allergy and Critical Care Medicine,Department of Medicine,University of Alabama at Birmingham,Birmingham,AL 35294,USA.
Microsc Microanal. 2018 Dec;24(6):708-712. doi: 10.1017/S1431927618015519. Epub 2018 Dec 5.
The intracellular concentration of calcium ion ([Ca2+]i) is a critical regulator of cell signaling and contractility of vascular smooth muscle cells (VSMCs). In this study, we employed an atomic force microscopy (AFM) nanoindentation-based approach to investigate the role of [Ca2+]i in regulating the cortical elasticity of rat cremaster VSMCs and the ability of rat VSMCs to adhere to fibronectin (Fn) matrix. Elevation of [Ca2+]i by ionomycin treatment increased rat VSMC stiffness and cell adhesion to Fn-biofunctionalized AFM probes, whereas attenuation of [Ca2+]i by 1,2-Bis (2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid tetrakis (acetoxymethyl ester) (BAPTA-AM) treatment decreased the mechanical and matrix adhesive properties of VSMCs. Furthermore, we found that ionomycin/BAPTA-AM treatments altered expression of α 5 integrin subunits and α smooth muscle actin in rat VSMCs. These data suggest that [Ca2+]i regulates VSMC elasticity and adhesion to the extracellular matrix by a potential mechanism involving changing dynamics of the integrin-actin cytoskeleton axis.
细胞内钙离子浓度（[Ca2+]i）是细胞信号传导和血管平滑肌细胞（VSMC）收缩性的关键调节因子。在本研究中，我们采用基于原子力显微镜（AFM）纳米压痕的方法，研究[Ca2+]i在调节大鼠提睾肌VSMC皮质弹性以及大鼠VSMC黏附于纤连蛋白（Fn）基质能力方面的作用。离子霉素处理使[Ca2+]i升高，增加了大鼠VSMC的硬度以及细胞对Fn生物功能化AFM探针的黏附，而1,2-双（2-氨基苯氧基）乙烷-N,N,N',N'-四乙酸四（乙酰氧甲基酯）（BAPTA-AM）处理使[Ca2+]i降低，降低了VSMC的机械性能和基质黏附特性。此外，我们发现离子霉素/BAPTA-AM处理改变了大鼠VSMC中α5整合素亚基和α平滑肌肌动蛋白的表达。这些数据表明，[Ca2+]i通过一种潜在机制调节VSMC弹性和对细胞外基质的黏附，该机制涉及改变整合素-肌动蛋白细胞骨架轴的动力学。
