Autocrine Role of Cytokines in Vascular Smooth Muscle

细胞因子在血管平滑肌中的自分泌作用

• 批准号: 6818774
• 负责人: Debbie Beasley
• 金额: $ 32.4万
• 依托单位: TUFTS MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 1992
• 资助国家: 美国
• 起止时间: 1992-02-01 至 2006-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6818774
• 关键词: Chlamydiaceae; antisense nucleic acid; atherosclerosis; autocrine; bacterial proteins; bactericidal immunity; cell proliferation; disease /disorder etiology; fatty acylation; gel mobility shift assay; heat shock proteins; human tissue; interleukin 1; laboratory mouse; lipopolysaccharides; mitogen activated protein kinase; mitogens; myristates; nuclear factor kappa beta; protein localization; receptor expression; tissue /cell culture; toll like receptor; transfection; vascular smooth muscle

Recent evidence suggests that chronic infection with the respiratory pathogen, Chlamydia pneumoniae, may contribute to the development of atherosclerosis. The long range objective of this proposal is to determine the mechanisms by which infection may contribute to enhanced vascular smooth muscle cell (VSMC) proliferation, a component of early atherosclerotic lesions. The working hypothesis for these studies is that VSMC recognize and respond to cell wall components of C. pneumoniae with a strong proliferative response and upregulation of interleukin-1alpha (IL1alpha) synthesis, which in turn amplifies and sustains the initial mitogenic signal elicited by chlamydial products. Studies during the previous grant period showed that the precursor form of IL1alpha is a potent membrane-associated growth factor for human VSMC (HVSMC), and that IL1-induced proliferation involves activation of TRAF6, NIK, and IKKs, leading to the persistent activation of NF-kappaB. Preliminary data indicate that a heat-labile component of C. pneumoniae is a potent mitogenic stimulus for HVSMC. The proposed studies will determine the mechanisms of C. pneumoniae-induced HVSMC proliferation, focusing on the role of Toll-like receptor 4 (TLR4), which is expressed by HVSMC. TLRs mediate recognition of bacterial products, including lipopolysaccharide and heat shock protein 60, have intracellular domains which are homologous to the type I IL1 receptor, and likewise activate TRAF6, NIK and IKKs. Two specific hypotheses will be tested in the proposed studies. First, C. pneumoniae induces HVSMC proliferation via activation of TLR4, with subsequent recruitment of TRAF6 and ultimate activation of NF-kappaB and p44/p42 mitogen-activated protein kinases. Second, autocrine production of IL1alpha, and its myristylation-dependent localization to the cell surface, sustains and enhances the primary effects of TLR4 activation. The specific aims are: to determine whether C. pneumoniae or its molecular components induce proliferation of HVSMC via TLR4- mediated activation of TRAF6, NIK, IKK, and ultimately NF-kappaB, and by TRAF6-mediated activation of p42/p44 mitogen-activated protein kinases; to determine whether autocrine production of IL1alpha precursor contributes to the mitogenic effect of C. pneumoniae in HVSMC; and to determine whether myristylation of lysine83 plays a crucial role in the mitogenic effects of IL1alpha precursor by targeting it to the plasma membrane. The studies will employ transient transfection with dominant negative mutants, TLR4 and IL1 receptor antagonists, and antisense oligonucleotides. The results of these studies will elucidate the potential roles of bacterial and chlamydial products in the pathogenesis of vascular disease.

最近的证据表明，慢性感染呼吸道病原体，肺炎衣原体，可能有助于动脉粥样硬化的发展。 该建议的长期目标是确定感染可能有助于增强血管平滑肌细胞（VSMC）增殖的机制，这是早期动脉粥样硬化病变的一个组成部分。 这些研究的工作假设是，VSMC识别并响应C。肺炎衣原体具有强烈的增殖反应和白细胞介素-1 α（IL 1 α）合成的上调，这反过来又放大和维持衣原体产物引起的初始促有丝分裂信号。上一个资助期的研究表明，IL 1 α的前体形式是人VSMC（HVSMC）的有效膜相关生长因子，IL 1诱导的增殖涉及TRAF 6、NIK和IKK的激活，导致NF-κ B的持续激活。 初步数据表明，C。pneumoniae是HVSMC的有效促有丝分裂刺激物。 这些研究将有助于确定C.肺炎诱导的HVSMC增殖，集中在由HVSMC表达的Toll样受体4（TLR 4）的作用。 TLR介导细菌产物（包括脂多糖和热休克蛋白60）的识别，具有与I型IL 1受体同源的细胞内结构域，并且同样激活TRAF 6、NIK和IKK。 两个特定的假设将在拟议的研究进行测试。 第一，C. pneumoniae通过激活TLR 4诱导HVSMC增殖，随后募集TRAF 6并最终激活NF-κ B和p44/p42丝裂原活化蛋白激酶。 第二，自分泌产生的IL 1 α，其肉豆蔻化依赖性定位到细胞表面，维持和增强TLR 4激活的主要作用。具体目的是：确定C。肺炎克雷伯氏菌或其分子组分通过TLR 4介导的TRAF 6、NIK、IKK和最终NF-κ B的活化，以及通过TRAF 6介导的p42/p44丝裂原活化蛋白激酶的活化诱导HVSMC增殖; HVSMC中的pneumonia;并确定赖氨酸83的肉豆蔻酰化是否在IL 1 α前体靶向质膜的促有丝分裂作用中起关键作用。 这些研究将采用显性阴性突变体、TLR 4和IL 1受体拮抗剂和反义寡核苷酸进行瞬时转染。 这些研究的结果将阐明细菌和衣原体产物在血管疾病发病机制中的潜在作用。