Monk P N, Banks P
Department of Molecular Biology and Biotechnology, University of Sheffield, U.K.
Biochim Biophys Acta. 1991 Apr 17;1092(2):251-5. doi: 10.1016/0167-4889(91)90164-s.
The adhesion of leukocytes to endothelial and other cell types is an essential part of the acute inflammatory response. One means by which adherence can be increased is by activation of the CD11/CD18 family of leukocyte glycoproteins. Chemotactic peptides, lipid mediators, phorbol esters and tumour necrosis factor are all able to increase the cell surface expression of one member of this family, CD11b/CD18 or Mac-1, by an unknown signal transduction mechanism. In this report, regulation of Mac-1 expression by C5a is shown to be independent of protein kinase C (PK-C) activation. The inhibitor of PK-C, H-7, has no effect on the action of C5a and only a slight effect on phorbol ester-induced up- and down-regulation of Mac-1, at a concentration that inhibits superoxide production in response to both factors by 40%. Inositol phospholipid hydrolysis, an important pathway leading to PK-C activation, and the transient increases in cytosolic Ca2+ associated with inositol phosphate production, are also shown to be not essential processes in C5a-stimulation of Mac-1 expression.
白细胞与内皮细胞及其他细胞类型的黏附是急性炎症反应的重要组成部分。增加黏附的一种方式是激活白细胞糖蛋白的CD11/CD18家族。趋化肽、脂质介质、佛波酯和肿瘤坏死因子都能够通过未知的信号转导机制增加该家族一个成员CD11b/CD18或Mac-1的细胞表面表达。在本报告中，C5a对Mac-1表达的调节显示独立于蛋白激酶C（PK-C）的激活。PK-C抑制剂H-7对C5a的作用没有影响，并且在抑制对这两种因子的超氧化物产生40%的浓度下，对佛波酯诱导的Mac-1上调和下调只有轻微影响。肌醇磷脂水解是导致PK-C激活的重要途径，以及与肌醇磷酸产生相关的胞质Ca2+瞬时增加，也显示在C5a刺激Mac-1表达中不是必需过程。
