Mechanisms of IL-1β-induced Expression of ICAM-1 in Cultured Pulmonary Epithelial Cells:Involvement of MAP Kinases and Akt in Transcription and Translation Levels.

• Main Authors: Tzu-Hua Chu, 朱姿樺
• Other Authors: Chuen-Mao Yang
• Format: Others
• Language: zh-TW
• Published: 2005
• Online Access: http://ndltd.ncl.edu.tw/handle/86478887901662144798

碩士 === 長庚大學 === 天然藥物研究所 === 94 === Interleukin-1β (IL-1β) has been shown to induce ICAM-1 expression in various cell types and contribute to inflammatory responses. Here, we report that in human pulmonary epithelial cells (A549), the mitogen-activated protein kinases (MAPKs) and nuclear factor-κB (NF-κB) pathways participate in IL-1β-induced ICAM-1 expression determined by Western blotting and RT-PCR analyses. IL-1β induced expression of ICAM-1 protein and mRNA in a time- and concentration-dependent manner. IL-1β increased ICAM-1 mRNA and protein expression, which were inhibited by inhibitors of MEK1/2 (U0126), p38 (SB202190), and c-Jun N-terminal kinase (JNK; SP600125). Accordingly, IL-1β stimulated phosphorylation of p42/p44 MAPK, p38, and JNK, which was attenuated by U0126, SB202190, and SP600125, respectively. In addition to MAPKs, intracellular signaling components may be involved in IL-1-induced ICAM-1 expression, we further determined whether these signaling pathways involved in ICAM-1 expression. Pretreatment with inhibitors of tyrosine kinase (genistein), Src (PP1), Ca2+ chelator (BAPTA/EDTA), Ca2+-ATPase (thapsigargin), Ca2+ channel blocker (Ni2+ and nifedipine), PKC (Gö6976), PC-PLC (D609), EGFR (AG1478), PDGFR (AG1296), PI3K (LY294002 and wortmannin), AP-1, NF-κB attenuated IL-1β-induced ICAM-1 expression. Taken together, these results suggest that IL-1β-induced ICAM-1 gene expression in A549 was involved the phosphorylation of p42/p44 MAPK, p38, and JNK, transactivation of tyrosine kinase receptors and translocation of NF-B pathways. Moreover, we demonstrate the relationship of Src, PDGFR, and Akt leading to ICAM-1 expression, we use selective pharmacological inhibitors：PP1, which can inhibit IL-1β-induced PDGFR phosphorylation and AG1296 also can attenuate IL-1β-induced Akt phosphorylation. Our results indicated that IL-1β-induced ICAM-1 expression was mediated through sequential activation of Src, PDGFR, and then Akt in A549 cells. Up-regulation of ICAM-1 enhanced neutrophil adhesion to A549 cells was inhibited by PD98059, U0126, SB202190, SP600125, PDTC, and helenalin, respectively. Taken together, these results suggest that the activation of p42/p44 MAPK, p38 MAPK, and JNK cascades and NF-κB translocation are required for IL-1β-induced ICAM-1 expression in A549 cells, leading to attract neutrophils adhesion. These results provide new insight into the mechanisms of IL-1β action that cytokines may promote inflammatory responses in the airway disease. An increased understanding of mechanisms in IL-1β-induced ICAM-1 expression on A549 may contribute potential therapeutic value in the treatment of airway inflammation.