The Journal of Toxicological Sciences
Online ISSN : 1880-3989
Print ISSN : 0388-1350
ISSN-L : 0388-1350
Original Article
Extracellular signal-regulated kinase (ERK) inhibition attenuates cigarette smoke extract (CSE) induced-death inducing signaling complex (DISC) formation in human lung fibroblasts (MRC-5) cells
Jeong-Woong ParkJin Young YoonYu Jin KimSun Young KyungSang Pyo LeeSung Hwan JeongChanil Moon
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JOURNAL FREE ACCESS

2010 Volume 35 Issue 1 Pages 33-39

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Abstract

Cigarette smoke (CS), a major risk factor in emphysema, causes cell death by incompletely understood mechanisms. Death-inducing signaling complex (DISC) formation is an initial event in Fas-mediated apoptosis. We demonstrated cigarette smoke extract (CSE) induced DISC formation in human lung fibroblasts (MRC-5). The aim of this study was to investigate the involvement of extracellular signal-regulated kinase (ERK) MAPK activation in CSE induced DISC formation. Immunoprecipitaion (IP) for Fas and Western Immunoblot (IB) analysis for caspase 8 were then performed to show DISC. Lactate dehydrogenase (LDH) release was measured using a cytotoxicity detection kit. MTT assay was used as a measure of cell viability. We demonstrated that CSE induces DISC formation in MRC-5 using IP for Fas and IB for caspase 8. ERK was expressed in MRC-5 exposed to CSE. MEK-1 inhibitor (PD98059) decreased DISC formation in MRC-5 exposed to 20% CSE at 1 hr, and cell viability, as assessed by colorimetric MTT assay, was increased in MEK-1 inhibitor treated MRC-5 cells after 24 hr CSE exposure compared to the control. Inhibiting ERK significantly decreased the caspase-3,-8 activity in MEK-1 inhibitor treated MRC-5 cells compared to the control.The DISC formation, initial event of extrinsic apoptotic pathway, is a primary component of CSE- induced death in MRC-5, and ERK activation plays an active role in the DISC formation and downstream pathway. These results suggest that modulation of ERK may have therapeutic potential in the prevention of smoke-related lung injury.

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© 2010 The Japanese Society of Toxicology
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