Fadeel Bengt
Division of Toxicology, Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden.
Antioxid Redox Signal. 2004 Apr;6(2):269-75. doi: 10.1089/152308604322899332.
Apoptosis is a program of cellular self-destruction culminating in the clearance of cell corpses by neighboring macrophages. Studies in recent years have served to characterize a number of structural and molecular plasma membrane alterations that act in concert to mediate efficient engulfment of cell corpses. Hence, "eat me" signals, including the anionic phospholipid phosphatidylserine (PS) and its oxidized counterpart, PS-OX, as well as the PS-binding protein, annexin I, are exposed on the surface of effete cells and function to mediate engulfment by neighboring phagocytic cells. Plasma membrane blebbing (zeiosis), a common feature of the apoptotic program, provides a structural context for the exposition of recognition signals insofar as PS molecules aggregate on the surface of these membrane protrusions. Apoptotic cells also secrete chemotactic factors ("seek me" signals), such as the phospholipid lysophosphatidylcholine, that recruit phagocytes to the site of the apoptotic lesion. Taken together, these events serve to mediate the disposal of effete cells prior to their necrotic disintegration, thus preventing the inflammation and tissue scarring that would otherwise ensue.
细胞凋亡是一种细胞自我毁灭程序，最终由邻近的巨噬细胞清除细胞尸体。近年来的研究已明确了一些结构和分子层面的质膜改变，这些改变共同作用以介导细胞尸体的有效吞噬。因此，“吃我”信号，包括阴离子磷脂磷脂酰丝氨酸（PS）及其氧化形式PS-OX，以及PS结合蛋白膜联蛋白I，会暴露于衰老细胞表面，并起到介导邻近吞噬细胞吞噬的作用。质膜起泡（胞质逸出）是细胞凋亡程序的一个常见特征，它为识别信号的暴露提供了结构背景，因为PS分子会聚集在这些膜突起的表面。凋亡细胞还会分泌趋化因子（“寻找我”信号），如磷脂溶血磷脂酰胆碱，将吞噬细胞招募到凋亡损伤部位。综上所述，这些事件有助于在衰老细胞发生坏死性解体之前对其进行处理，从而防止炎症和组织瘢痕形成，否则这些情况将会发生。
