Dept. of Biochemistry, Univ. of Nevada School of Medicine, Reno, NV 89557, USA.
Am J Physiol Cell Physiol. 2010 May;298(5):C1006-17. doi: 10.1152/ajpcell.00359.2009. Epub 2010 Feb 17.
The purpose of this study was to determine whether extracellular matrix (ECM) composition through integrin receptors modulated the volume-sensitive osmolyte anion channels (VSOACs) in skeletal muscle-derived C2C12 cells. Cl(-) currents were recorded in whole cell voltage-clamped cells grown on laminin (LM), fibronectin (FN), or in the absence of a defined ECM (NM). Basal membrane currents recorded in isotonic media (300 mosmol/kg) were larger in cells grown on FN (3.8-fold at +100 mV) or LM (8.8-fold at +100 mV) when compared with NM. VSOAC currents activated by cell exposure to hypotonic solution were larger in cells grown on LM (1.72-fold at +100 mV) or FN (1.75-fold at +100 mV) compared with NM. Additionally, the kinetics of VSOAC activation was approximately 27% quicker on FN and LM. These currents were tamoxifen sensitive, displayed outward rectification, reversed at the equilibrium potential of Cl(-) and inactivated at potentials >+60 mV. Specific knockdown of beta(1)-integrin by short hairpin RNA interference strongly inhibited the VSOAC Cl(-) currents in cells plated on FN. In conclusion, ECM composition and integrins profoundly influence the biophysical properties and mechanisms of onset of VSOACs.
本研究旨在确定细胞外基质 (ECM) 通过整合素受体组成是否调节骨骼肌衍生 C2C12 细胞中的体积敏感渗透物阴离子通道 (VSOAC)。在层粘连蛋白 (LM)、纤维连接蛋白 (FN) 或无定义 ECM (NM) 上生长的细胞进行全细胞膜片钳电压钳记录时，Cl(-)电流。在等渗介质 (300 mosmol/kg) 中记录到的基底膜电流在 FN (+100 mV 时 3.8 倍) 或 LM (+100 mV 时 8.8 倍) 上生长的细胞比 NM 大。与 NM 相比，暴露于低渗溶液后激活的 VSOAC 电流在 LM (+100 mV 时 1.72 倍) 或 FN (+100 mV 时 1.75 倍) 上生长的细胞更大。此外，VSOAC 激活的动力学在 FN 和 LM 上大约快 27%。这些电流对他莫昔芬敏感，呈外向整流，在 Cl(-)的平衡电位处反转，并在 >+60 mV 的电位下失活。用短发夹 RNA 干扰特异性敲低 β(1)-整合素强烈抑制了 FN 上细胞的 VSOAC Cl(-)电流。总之，细胞外基质组成和整合素深刻影响 VSOAC 的生物物理特性和起始机制。
