Wang J, Lukse E, Seth A, McCulloch C A
CIHR Group in Periodontal Physiology, Faculty of Dentistry, University of Toronto, Ontario, Canada.
Tissue Cell. 2001 Feb;33(1):86-96. doi: 10.1054/tice.2000.0160.
Mechanical stretch regulates alpha-smooth muscle actin (SMA) expression in myofibroblasts but limited replication and cellular heterogeneity have hampered definitive studies in vitro. We examined the role of applied force in regulating SMA expression in conditionally immortalized cardiac fibroblast lines derived from H-2Kb-tsA58 transgenic mice. When plated in differentiating conditions (37 degrees C without interferon-gamma), transgenic myofibroblasts exhibited vimentin staining, no desmin staining and abundant SMA in well-developed stress fibers that were indistinguishable from controls. Magnetically-generated tensile forces (approximately 500 pN/cell) applied through collagen-coated magnetite beads selectively reduced SMA but not beta-actin mRNA and protein content in both cell types. The early loss of SMA was due in part to selective leakage into the cell culture medium. Depolymerization of actin filaments with cytochalasin D blocked the force-induced reduction of SMA. Cardiac fibroblast lines established from H-2Kb-tsA58 transgenic mice provide a phenotypically stable source of cells for studying the role of physical forces in regulating SMA.
机械牵张可调节肌成纤维细胞中α-平滑肌肌动蛋白（SMA）的表达，但有限的复制能力和细胞异质性阻碍了体外的确切研究。我们研究了施加力在调节源自H-2Kb-tsA58转基因小鼠的条件性永生化心脏成纤维细胞系中SMA表达的作用。当接种于分化条件下（37℃，无γ-干扰素）时，转基因肌成纤维细胞呈现波形蛋白染色，无结蛋白染色，且在发育良好的应力纤维中有丰富的SMA，与对照无差异。通过胶原包被的磁铁矿珠施加的磁致拉力（约500 pN/细胞）选择性降低了两种细胞类型中SMA的表达，但不影响β-肌动蛋白的mRNA和蛋白质含量。SMA的早期减少部分归因于其选择性渗漏到细胞培养基中。用细胞松弛素D使肌动蛋白丝解聚可阻断力诱导的SMA减少。从H-2Kb-tsA58转基因小鼠建立的心脏成纤维细胞系为研究物理力在调节SMA中的作用提供了表型稳定的细胞来源。
