Küchler Jens, Grützkau Andreas, Henz Beate M, Krüger-Krasagakis Sabine
Department of Dermatology and Allergy, Charité, Humboldt University, Berlin, Germany.
Arch Dermatol Res. 2006 Sep;298(4):153-61. doi: 10.1007/s00403-006-0676-y. Epub 2006 Jul 25.
Specific heterodimers of alpha and beta integrins are implicated in mediating adhesion and functional activation of mast cells to extracellular matrix (ECM) proteins, determining thus homing, secretion and tissue distribution of these cells. In the present study, we have examined integrin expression and associated morphological features of mast cells adhering to ECM, also depending on cell activation and under the influence of protein kinase C (PKC) inhibitors. Unstimulated and PMA-activated human leukaemic mast cells (HMC-1 line) were allowed to adhere to fibronectin or vitronectin-coated surfaces. Cells were specifically stained for actin, beta(1, )alpha(1)-alpha(6), alpha(v) and alpha(v)beta(5 )integrins and were evaluated by fluorescence microscopy and confocal laser scan microscopy. Spontaneously adhering cells rapidly assumed an oblong shape, with pronounced formation of filopodia, whereas PMA-stimulated cells were round in shape. Clustering of integrins on filopodia and on comma-like shapes at the cell circumference in rounded cells was noted only for alpha(4), alpha(5) and beta(1 )chains in fibronectin-adhering cells, and for alpha(v) and alpha(v)beta(5) chains in vitronectin-adhering cells. On double staining, clustered integrins co-localized with each other and with actin at the cell membrane and along intracellular tension lines of actin filaments. PKC inhibitors affected the shape of cells, but adhesion was maintained. These data provide a morphological correlate to previously reported functional studies, demonstrating clustering of selected integrins during ECM adhesion at the cell membrane. This was associated with alignment of integrins along actin filaments within the cytoplasm, PKC signalling and changes in shape and activation of mast cells.
α和β整合素的特定异二聚体参与介导肥大细胞与细胞外基质（ECM）蛋白的黏附及功能激活，从而决定这些细胞的归巢、分泌和组织分布。在本研究中，我们检测了黏附于ECM的肥大细胞的整合素表达及相关形态特征，这也取决于细胞激活情况以及蛋白激酶C（PKC）抑制剂的影响。将未刺激和经佛波酯（PMA）激活的人白血病肥大细胞（HMC-1系）置于纤连蛋白或玻连蛋白包被的表面。对细胞进行肌动蛋白、β(1)、α(1)-α(6)、α(v)和α(v)β(5)整合素的特异性染色，并通过荧光显微镜和共聚焦激光扫描显微镜进行评估。自发黏附的细胞迅速呈现椭圆形，有明显的丝状伪足形成，而PMA刺激的细胞呈圆形。仅在黏附于纤连蛋白的细胞中的α(4)、α(5)和β(1)链，以及黏附于玻连蛋白的细胞中的α(v)和α(v)β(5)链上，观察到整合素在丝状伪足上以及圆形细胞的细胞周边呈逗号样形状处聚集。在双重染色时，聚集的整合素在细胞膜处以及沿肌动蛋白丝的细胞内张力线相互共定位，并与肌动蛋白共定位。PKC抑制剂影响细胞形状，但黏附得以维持。这些数据为先前报道的功能研究提供了形态学关联，证明在ECM黏附过程中选定的整合素在细胞膜处聚集。这与整合素沿细胞质内的肌动蛋白丝排列、PKC信号传导以及肥大细胞的形状和激活变化有关。
