title: MAPK pathway mediates EGR-1-HSP70-dependent cigarette smoke-induced chemokine production.
abstract: Cigarette smoking, a major risk factor for chronic obstructive pulmonary disease, can cause airway inflammation, airway narrowing, and loss of elasticity, leading to chronic airflow limitation. In this report, we sought to define the signaling pathways activated by smoke and to identify molecules responsible for cigarette smoke-induced inflammation. We applied cigarette smoke water extract (CSE) to primary human lung fibroblasts and found that CSE significantly increased CXC chemokine IL-8 production. Meanwhile, 70-kDa heat shock protein (HSP70) was also induced by CSE in a dose- and time-dependent manner. CSE treatment stimulated HSP70 secretion by primary fibroblasts, which augmented IL-8 production. This was further confirmed by exogenously added recombinant HSP70. Using HSP70 small interfering RNA, we confirmed that CSE-induced chemokine production was dependent on heat shock protein expression. Further investigation showed that CSE could also stimulate early growth response-1 (EGR-1) in an ERK-dependent manner and that the expression of HSP70 was EGR-1 dependent. In view of these findings, we hypothesize that the MAPK-EGR-1-HSP70 pathway regulates the cigarette smoke-induced inflammatory process.
authors.affiliation: Pulmonary, Allergy and Critical Care Medicine Division, Department of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15213, USA.
authors.forename: Chao-Jun
authors.initials: CJ
authors.lastname: Li
authors.forename: Wen
authors.initials: W
authors.lastname: Ning
authors.forename: Michael A
authors.initials: MA
authors.lastname: Matthay
authors.forename: Carol A
authors.initials: CA
authors.lastname: Feghali-Bostwick
authors.forename: Augustine M K
authors.initials: AM
authors.lastname: Choi
mesh_terms: D002460:Cell Line; D002478:Cells, Cultured; D018925:Chemokines / Q000235:genetics*; D004277:DNA, Single-Stranded / Q000235:genetics*; D005347:Fibroblasts / Q000502:physiology; D005786:Gene Expression Regulation; D018840:HSP70 Heat-Shock Proteins / Q000235:genetics*; D006801:Humans; D016209:Interleukin-8 / Q000235:genetics; D008168:Lung / Q000502:physiology*; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism*; D034741:RNA, Small Interfering; D012906:Smoke / Q000009:adverse effects*
chemical_list: D018925:Chemokines; C400152:DNA enzyme ED5; D004277:DNA, Single-Stranded; D018840:HSP70 Heat-Shock Proteins; D016209:Interleukin-8; D034741:RNA, Small Interfering; D012906:Smoke; D020928:Mitogen-Activated Protein Kinases