U937세포주의 분화에 따른 lipocortin 1의 발현 및 glucocorticoid의 영향

다국어 초록 (Multilingual Abstract)

Lipocortin represents a family of similar Ca depentent phospholipid binding proteins capable of blocking the activity of phospholipase A (PLA) in vitro. Generally, these proteins are believed to inhibit the release of arachidonic acid from phos- pholipids and the formation of lipid mediators such ss prostaglandin, leukotriene, and platelet activating factor. Lipocortin 1, initially identified as a glucocorticoid responsive protein in macrophages and neutrophils has been implicated in transmembrane signal transduction during growth factor mediated cell proliferation and transformation. To define the synthesis and its regulation, we investigated the expression of lipocortin 1 in both the mRNA and protein level in U937 cell line in the presence of several differentiation factors. The results were as follows. 1. The expression of lipocortin 1 and its mRNA was increased during TPA induced differentiation of U937 cells to maximum of 2 -fold and 5-fold respectively. Both the protein and mRNA levels decreased after 48 hours. 2. With the treatment with IFN y, the ex- pression of CD16 was increased. However, the protein and mRNA levels of lipocortin 1 were, not changed significantly. 3. Neither the dexamethasone or hydrocortisone have any effects on the expression of lipocortin 1 in both TPA-differentiated and undifferentiated U937 cells. The results from this study would give a light on defining the functional role of lipocortin 1 in macro monocyte cell lineage and possibly some informstive clues for the pathogenic mechanisms of the inflammatory diseases.