Yang C M, Luo S F, Wang C C, Chiu C T, Chien C S, Lin C C, Hsiao L D
Department of Pharmacology, College of Medicine, Chang Gung University, 259 Wen-Hwa 1 Road, Kwei-San, Tao-Yuan, Taiwan.
Br J Pharmacol. 2000 Jun;130(4):891-9. doi: 10.1038/sj.bjp.0703359.
The elevated levels of inflammatory cytokines such as tumour necrosis factor-alpha (TNF-alpha) and interleukin-1beta (IL-1beta) have been found in the fluid of airways in symptomatic asthmatics. These cytokines have been considered as mitogens to stimulate cell proliferation in tracheal smooth muscle cells (TSMCs). We therefore investigated the effects of TNF-alpha and IL-1beta on cell proliferation and activation of p42/p44 mitogen-activated protein kinase (MAPK) in these cells. TNF-alpha and IL-1beta induced [(3)H]-thymidine incorporation in a time- and concentration-dependent manner. The maximal stimulation of [(3)H]-thymidine incorporation induced by TNF-alpha and IL-1beta was seen 12 h after incubation with these cytokines. In response to TNF-alpha and IL-1beta, p42/p44 MAPK was activated with a concentration-dependent manner in TSMCs. Pretreatment of TSMCs with pertussis toxin did not change DNA synthesis and phosphorylation of MAPK induced by TNF-alpha and IL-1beta. These responses were attenuated by a tyrosine kinase inhibitor herbimycin, a phosphatidyl choline (PC)-phospholipase C (PLC) inhibitor D609, a phosphatidyl inositide (PI)-PLC inhibitor U73122, a protein kinase C inhibitor staurosporine, and removal of Ca(2+) by addition of BAPTA/AM plus EGTA. TNF-alpha- and IL-1beta-induced [(3)H]-thymidine incorporation and phosphorylation of p42/p44 MAPK was completely inhibited by PD98059 (an inhibitor of MEK1/2), indicating that activation of MEK1/2 was required for these responses. These results suggest that the mitogenic effects of TNF-alpha and IL-1beta were mediated through the activation of MEK1/2 and p42/p44 MAPK pathway. TNF-alpha- and IL-1beta-mediated responses were modulated by PLC, Ca(2+), PKC, and tyrosine kinase associated with cell proliferation in TSMCs.
在有症状的哮喘患者气道分泌物中发现肿瘤坏死因子-α（TNF-α）和白细胞介素-1β（IL-1β）等炎症细胞因子水平升高。这些细胞因子被认为是刺激气管平滑肌细胞（TSMCs）增殖的促有丝分裂原。因此，我们研究了TNF-α和IL-1β对这些细胞增殖以及p42/p44丝裂原活化蛋白激酶（MAPK）激活的影响。TNF-α和IL-1β以时间和浓度依赖性方式诱导[³H]胸腺嘧啶核苷掺入。与这些细胞因子孵育12小时后，观察到TNF-α和IL-1β诱导的[³H]胸腺嘧啶核苷掺入的最大刺激作用。响应TNF-α和IL-1β，p42/p44 MAPK在TSMCs中以浓度依赖性方式被激活。用百日咳毒素预处理TSMCs不会改变TNF-α和IL-1β诱导的DNA合成和MAPK磷酸化。这些反应被酪氨酸激酶抑制剂赫曲霉素、磷脂酰胆碱（PC）-磷脂酶C（PLC）抑制剂D609、磷脂酰肌醇（PI）-PLC抑制剂U73122、蛋白激酶C抑制剂星形孢菌素以及通过添加BAPTA/AM加EGTA去除Ca²⁺所减弱。PD98059（MEK1/2抑制剂）完全抑制了TNF-α和IL-1β诱导的[³H]胸腺嘧啶核苷掺入和p42/p44 MAPK磷酸化，表明这些反应需要MEK1/2的激活。这些结果表明，TNF-α和IL-1β的促有丝分裂作用是通过MEK1/2和p42/p44 MAPK途径的激活介导的。TNF-α和IL-1β介导的反应受到与TSMCs细胞增殖相关的PLC、Ca²⁺、PKC和酪氨酸激酶的调节。
