Amrani Y, Lazaar A L, Hoffman R, Amin K, Ousmer S, Panettieri R A
Pulmonary, Allergy and Critical Care Division, Department of Medicine, University of Pennsylvania Medical Center, Philadelphia 19104-6160, USA.
Mol Pharmacol. 2000 Jul;58(1):237-45. doi: 10.1124/mol.58.1.237.
Tumor necrosis factor-alpha (TNFalpha) stimulates the expression of intercellular adhesion molecule-1 (ICAM-1) by activating the transcription factor nuclear factor-kappaB (NF-kappaB) in human airway smooth muscle (ASM) cells. This study characterizes the receptor involved as well as critical downstream signaling events mediating cytokine-induced NF-kappaB activation and ICAM-1 expression. TNFalpha stimulation for 1 to 4 h induced ICAM-1 expression in human ASM cells. This rapid TNFalpha-induced ICAM-1 expression enhanced T-lymphocyte adhesion to ASM cells, which was inhibited by anti-ICAM-1 antibodies. Using immunostaining, we demonstrated that TNFalpha receptors TNFR1 and TNFR2 are expressed on native human tracheal smooth muscle. Treatment of cells with htr-9, an antibody that specifically activates TNFR1, also stimulated expression of ICAM-1 mRNA and protein. Utr-1, a blocking antibody to TNFR2, did not affect TNFalpha-mediated ICAM-1 expression. Both TNFalpha and htr-9 increased luciferase activity in ASM cells transfected with a NF-kappaB reporter plasmid. Overexpression of a dominant negative TNF receptor-associated factor 2 construct, lacking the NH(2)-terminal RING finger, completely abrogated both TNFalpha- and htr-9-mediated increases in NF-kappaB reporter activity. Thapsigargin, an agent that depletes intracellular calcium stores, abrogated both cytokine-mediated NF-kappaB-dependent ICAM-1 mRNA transcription and protein expression but had no effect on IkappaB degradation. In addition, chelating cytosolic calcium with 1,2-bis(2-aminophenoxy)ethane-N,N,N', N'-tetraacetic acid acetoxymethyl ester also inhibited cytokine TNFalpha-induced ICAM-1 expression. These data suggest that TNFR1, through a TNF receptor-associated factor 2-NF-kappaB signaling pathway, mediates TNFalpha-induced expression of ICAM-1 on ASM cells by involving a thapsigargin-sensitive signaling pathway.
肿瘤坏死因子-α（TNFα）通过激活人气道平滑肌（ASM）细胞中的转录因子核因子-κB（NF-κB）来刺激细胞间黏附分子-1（ICAM-1）的表达。本研究对所涉及的受体以及介导细胞因子诱导的NF-κB激活和ICAM-1表达的关键下游信号事件进行了表征。TNFα刺激1至4小时可诱导人ASM细胞中ICAM-1的表达。这种由TNFα快速诱导的ICAM-1表达增强了T淋巴细胞对ASM细胞的黏附，而抗ICAM-1抗体可抑制这种黏附。通过免疫染色，我们证明TNFα受体TNFR1和TNFR2在天然人气管平滑肌上表达。用特异性激活TNFR1的抗体htr-9处理细胞，也可刺激ICAM-1 mRNA和蛋白的表达。TNFR2的阻断抗体Utr-1不影响TNFα介导的ICAM-1表达。TNFα和htr-9均可增加用NF-κB报告质粒转染的ASM细胞中的荧光素酶活性。缺乏NH（2）-末端RING指的显性负性TNF受体相关因子2构建体的过表达，完全消除了TNFα和htr-9介导的NF-κB报告活性的增加。毒胡萝卜素是一种耗尽细胞内钙储存库的试剂，它消除了细胞因子介导的NF-κB依赖性ICAM-1 mRNA转录和蛋白表达，但对IkappaB降解没有影响。此外，用1,2-双（2-氨基苯氧基）乙烷-N，N，N'，N'-四乙酸乙酰甲酯螯合胞质钙也可抑制细胞因子TNFα诱导的ICAM-1表达。这些数据表明，TNFR1通过TNF受体相关因子2-NF-κB信号通路，通过涉及毒胡萝卜素敏感的信号通路，介导TNFα诱导的ASM细胞上ICAM-
