Lee Chiang-Wen, Chien Chin-Sung, Yang Chuen-Mao
Dept. of Pharmacology, College of Medicine, Chang Gung Univ., 259 Wen-Hwa 1 Road, Kwei-San, Tao-Yuan, Taiwan.
Am J Physiol Lung Cell Mol Physiol. 2004 May;286(5):L921-30. doi: 10.1152/ajplung.00124.2003.
Lipoteichoic acid (LTA), the principal component of the cell wall of gram-positive bacteria, triggers several inflammatory responses. However, the mechanisms underlying its action on human tracheal smooth muscle cells (HTSMCs) were largely unknown. This study was to investigate the mechanisms underlying LTA-stimulated p42/p44 mitogen-activated protein kinase (MAPK) using Western blotting assay. LTA stimulated phosphorylation of p42/p44 MAPK via a Toll-like receptor 2 (TLR2). Pretreatment with pertussis toxin attenuated the LTA-induced responses. LTA-stimulated phosphorylation of p42/p44 MAPK was attenuated by inhibitors of tyrosine kinase (genistein), phosphatidylcholine-phospholipase C (PLC; D609), phosphatidylinositol (PI)-PLC (U-73122), PKC (staurosporine, Gö-6976, rottlerin, or Ro-318220), MEK1/2 (U-0126), PI 3-kinase (LY-294002 and wortmannin), and an intracellular Ca(2+) chelator (BAPTA-AM). LTA directly evoked initial transient peak of Ca(2+), supporting the involvement of Ca(2+) mobilization in LTA-induced responses. These results suggest that in HTSMCs, LTA-stimulated p42/p44 MAPK phosphorylation is mediated through a TLR2 receptor and involves tyrosine kinase, PLC, PKC, Ca(2+), MEK, and PI 3-kinase.
脂磷壁酸（LTA）是革兰氏阳性菌细胞壁的主要成分，可引发多种炎症反应。然而，其作用于人类气管平滑肌细胞（HTSMC）的潜在机制在很大程度上尚不清楚。本研究旨在通过蛋白质免疫印迹法研究LTA刺激p42/p44丝裂原活化蛋白激酶（MAPK）的潜在机制。LTA通过Toll样受体2（TLR2）刺激p42/p44 MAPK的磷酸化。百日咳毒素预处理可减弱LTA诱导的反应。酪氨酸激酶抑制剂（染料木黄酮）、磷脂酰胆碱-磷脂酶C（PLC；D609）、磷脂酰肌醇（PI）-PLC（U-73122）、蛋白激酶C（PKC；星形孢菌素、Gö-6976、罗勒菌素或Ro-318220）、MEK1/2（U-0126）、PI 3-激酶（LY-294002和渥曼青霉素）以及细胞内Ca²⁺螯合剂（BAPTA-AM）均可减弱LTA刺激的p42/p44 MAPK磷酸化。LTA直接诱发细胞内Ca²⁺初始瞬时峰值，支持Ca²⁺动员参与LTA诱导的反应。这些结果表明，在HTSMC中，LTA刺激的p42/p44 MAPK磷酸化是通过TLR2受体介导的，并且涉及酪氨酸激酶、PLC、PKC、Ca²⁺、MEK和PI 3-激酶。
