Beppu M, Azuma M, Maruyama N, Kikugawa K
School of Pharmacy, Tokyo University of Pharmacy and Life Science, 1432-1 Horinouchi, Hachioji, Tokyo 192-0392, Japan.
Biochim Biophys Acta. 2001 Apr 23;1538(2-3):119-28. doi: 10.1016/s0167-4889(00)00106-3.
Macrophages recognize oxidatively damaged autologous erythrocytes, and cell surface fibronectin of macrophages enhances the recognition (Beppu et al., FEBS Lett. 295 (1991) 135-140). In the present study, mechanisms of enhanced macrophage recognition of oxidatively damaged erythrocytes by fibronectin were investigated. Monolayers of thioglycollate-induced mouse peritoneal macrophages with cell surface fibronectin recognized autologous erythrocytes oxidized with an iron catalyst ADP/Fe(3+). The macrophage recognition of the oxidized erythrocytes was inhibited partially by pretreatment of the macrophage monolayers with a Ca(2+) channel blocker (diltiazem), calmodulin inhibitors (W-7, trifluoperazine, chlorpromazine and dibucaine), an inhibitor of myosin light chain kinase (ML-9), a microfilament formation inhibitor (cytochalasin B), phospholipase A(2) inhibitors (4-bromophenacyl bromide, mepacrine) and cyclooxygenase inhibitors (indomethacin and aspirin). Monolayers of macrophages depleted of fibronectin by trypsinization lost the ability of recognizing oxidized erythrocytes, but acquired the ability when stimulated with a fibronectin-coated coverslip. The recognition of fibronectin-stimulated trypsinized macrophages was also inhibited by the above inhibitors. On treatment with Ca ionophore A23187, trypsinized macrophages acquired the ability to recognize oxidized erythrocytes. The recognition of Ca ionophore-stimulated trypsinized macrophages was inhibited by the above inhibitors except the Ca(2+) channel blocker. These results indicate that the Ca(2+) signaling including Ca(2+) influx, calmodulin activation and myosin light chain phosphorylation are involved in the fibronectin stimulation of the recognition of macrophages for oxidized erythrocytes. Involvement of microfilament formation and arachidonate cascade in the fibronectin stimulation was also suggested.
巨噬细胞能够识别氧化损伤的自体红细胞，并且巨噬细胞的细胞表面纤连蛋白会增强这种识别作用（Beppu等人，《欧洲生物化学学会联合会快报》295 (1991) 135 - 140）。在本研究中，对纤连蛋白增强巨噬细胞对氧化损伤红细胞识别的机制进行了研究。具有细胞表面纤连蛋白的巯基乙酸盐诱导的小鼠腹腔巨噬细胞单层能够识别被铁催化剂ADP/Fe(3+)氧化的自体红细胞。巨噬细胞单层用Ca(2+)通道阻滞剂（地尔硫卓）、钙调蛋白抑制剂（W - 7、三氟拉嗪、氯丙嗪和丁卡因）、肌球蛋白轻链激酶抑制剂（ML - 9）、微丝形成抑制剂（细胞松弛素B）、磷脂酶A(2)抑制剂（4 - 溴苯甲酰溴、米帕林）和环氧化酶抑制剂（吲哚美辛和阿司匹林）预处理后，对氧化红细胞的巨噬细胞识别作用会受到部分抑制。经胰蛋白酶处理耗尽纤连蛋白的巨噬细胞单层失去了识别氧化红细胞的能力，但在用纤连蛋白包被的盖玻片刺激后获得了该能力。上述抑制剂也会抑制纤连蛋白刺激的经胰蛋白酶处理的巨噬细胞的识别作用。用钙离子载体A23187处理后，经胰蛋白酶处理的巨噬细胞获得了识别氧化红细胞的能力。除Ca(2+)通道阻滞剂外，上述抑制剂会抑制钙离子载体刺激的经胰蛋白酶处理的巨噬细胞的识别作用。这些结果表明，包括Ca(2+)内流、钙调蛋白激活和肌球蛋白轻链磷酸化在内的Ca(2+)信号传导参与了纤连蛋白对巨噬细胞识别氧化红细胞的刺激作用。还提示了微丝形成和花生四烯酸级联反应在纤连蛋白刺激中的作用。
