Walker T R, Moore S M, Lawson M F, Panettieri R A, Chilvers E R
Rayne Laboratory, Respiratory Medicine Unit, Department of Medicine (Royal Infirmary of Edinburgh), University of Edinburgh Medical School, Edinburgh EH8 9AG, UK.
Mol Pharmacol. 1998 Dec;54(6):1007-15. doi: 10.1124/mol.54.6.1007.
Proliferation of airway smooth muscle results from persistent inflammatory cytokine and growth factor stimulation and is a critical component of airway luminal narrowing in chronic asthma. Using primary cultures of bovine tracheal smooth muscle (BTSM) cells to examine the signaling basis of cell proliferation, platelet-derived growth factor (PDGF)-BB and thrombin (which act through distinct receptor types) were found to induce DNA synthesis in BTSM cells. Mitogen-induced DNA synthesis could be completely inhibited by LY294002, a selective phosphoinositide 3-kinase (PtdIns 3-kinase) inhibitor. Exposure of BTSM cells to PDGF-BB or thrombin resulted in rapid activation of PtdIns 3-kinase and accumulation of phosphoinositide-3,4,5-trisphosphate. Protein kinase B, a novel signaling protein kinase, was identified in BTSM cells and was activated by PDGF-BB and thrombin in a PtdIns 3-kinase-dependent manner; this may underlie mitogen-stimulated activation of p70(s6k). PD98059, a mitogen-activated protein kinase kinase 1 inhibitor, also partially inhibited PDGF-BB- and thrombin-stimulated DNA synthesis, indicating a modulatory role for mitogen-activated protein kinase in proliferation. GF109203X, Ro 31-8220, calphostin C, and chelerythrine (selective protein kinase C inhibitors) had no effect on PDGF-BB- or thrombin-stimulated DNA synthesis, suggesting that, despite abolishment of mitogen-stimulated protein kinase C activity, cell proliferation stimulated by PDGF-BB and thrombin is protein kinase C-independent. These data demonstrate that the PtdIns 3-kinase/protein kinase B pathway represents a key signaling route in airway smooth muscle proliferation, with the mitogen-activated protein kinase kinase 1/mitogen-activated protein kinase cascade providing a complementary signal required for the full mitogenic response.
气道平滑肌的增殖源于持续的炎性细胞因子和生长因子刺激，是慢性哮喘气道管腔狭窄的关键组成部分。利用牛气管平滑肌（BTSM）细胞的原代培养物来研究细胞增殖的信号基础，发现血小板衍生生长因子（PDGF）-BB和凝血酶（通过不同受体类型起作用）可诱导BTSM细胞中的DNA合成。丝裂原诱导的DNA合成可被LY294002（一种选择性磷酸肌醇3激酶（PtdIns 3激酶）抑制剂）完全抑制。将BTSM细胞暴露于PDGF-BB或凝血酶会导致PtdIns 3激酶的快速激活以及磷酸肌醇-3,4,5-三磷酸的积累。蛋白激酶B是一种新型信号蛋白激酶，在BTSM细胞中被鉴定出来，并以PtdIns 3激酶依赖的方式被PDGF-BB和凝血酶激活；这可能是丝裂原刺激的p70（s6k）激活的基础。PD98059，一种丝裂原活化蛋白激酶激酶1抑制剂，也部分抑制了PDGF-BB和凝血酶刺激的DNA合成，表明丝裂原活化蛋白激酶在增殖中起调节作用。GF109203X、Ro 31-8220、钙磷蛋白C和白屈菜红碱（选择性蛋白激酶C抑制剂）对PDGF-BB或凝血酶刺激的DNA合成没有影响，这表明，尽管丝裂原刺激的蛋白激酶C活性被消除，但PDGF-BB和凝血酶刺激的细胞增殖是不依赖蛋白激酶C的。这些数据表明，PtdIns 3激酶/蛋白激酶B途径代表了气道平滑肌增殖中的关键信号通路，丝裂原活化蛋白激酶激酶1/丝裂原活化蛋白激酶级联提供了完全促有丝分裂反应所需的互补信号。
