Bolognese B, McCord M, Marshall L A
SmithKline Beecham Pharmaceuticals, Inflammation and Respiratory Pharmacology, King of Prussia, PA 19406-0939, USA.
Biochim Biophys Acta. 1995 May 17;1256(2):201-9. doi: 10.1016/0005-2760(95)00023-6.
Elicited guinea pig macrophages collected from inflammatory peritoneal exudate release soluble 14 kDa phospholipase A2 (PLA2) and prostaglandin E2 (PGE2) into surrounding media during culture (Marshall et al. (1994) J. Lipid Med. 10, 295-313). The effect of transformation growth factor beta 1 (TGF beta), an immunoregulatory growth factor, was examined in this system. Exposure of cultured macrophages to TGF beta reduced both the activity and protein levels of 14 kDa PLA2 measured in conditioned media. This inhibition occurred within the first 6-8 h, was prevalent through 72 h of exposure and was dependent on TGF beta concentration. The reduction, however, never reached more than 40-60%. Evaluation of the cellular PLA2 activity confirmed the existence of an immunologically-related 14 kDa PLA2 (ELISA) in the particulate fraction and an 85 kDa PLA2 (Western analysis) in the cytosol. Exposure to TGF beta halved the particulate activity and protein levels of 14 kDa PLA2 which was consistent with the reduction in the secreted form. Alternatively, TGF beta induced an increase in cytosolic 85 kDa PLA2 (activity and protein) which was not apparent until 12 h and significant at 20-24 h of exposure. This demonstrates that TGF beta differentially regulates the production of these two enzymes. Despite this, neither PGE2 synthesis nor the up-regulated cyclooxygenase -II were altered by TGF beta treatment suggesting that maximal prostanoid synthesis had been reached.
从炎性腹膜渗出物中收集的豚鼠巨噬细胞在培养过程中会向周围培养基中释放可溶性14 kDa磷脂酶A2（PLA2）和前列腺素E2（PGE2）（Marshall等人，（1994年）《脂质医学杂志》10，295 - 313）。本研究在该系统中检测了免疫调节生长因子转化生长因子β1（TGFβ）的作用。将培养的巨噬细胞暴露于TGFβ可降低条件培养基中测得的14 kDa PLA2的活性和蛋白质水平。这种抑制作用在最初的6 - 8小时内发生，在暴露72小时内普遍存在，并且依赖于TGFβ的浓度。然而，这种降低从未超过40 - 60%。对细胞PLA2活性的评估证实，在颗粒部分存在一种与免疫相关的14 kDa PLA2（酶联免疫吸附测定），在细胞质中存在一种85 kDa PLA2（蛋白质免疫印迹分析）。暴露于TGFβ使颗粒部分14 kDa PLA2的活性和蛋白质水平减半，这与分泌形式的降低一致。另外，TGFβ诱导细胞质中85 kDa PLA2（活性和蛋白质）增加，这种增加直到12小时才明显，在暴露20 - 24小时时显著。这表明TGFβ对这两种酶的产生有不同的调节作用。尽管如此，TGFβ处理并未改变PGE2的合成或上调的环氧化酶-II，这表明已达到前列腺素合成的最大值。
