title: Role of protein kinase C-η in cigarette smoke extract-induced apoptosis in MRC-5-cells.
abstract: Cigarette smoke (CS) is a major risk factor for emphysema, which causes cell death in structural cells of the lung by mechanisms that are still not completely understood. We demonstrated previously that CS extract (CSE) induces caspase activation in MRC-5 human lung fibroblasts, activated protein kinase C-η (PKC-η), and translocated PKC-η from the cytosol to the membrane. The objective of this study was to investigate the involvement of PKC-η activation in a CSE-induced extrinsic apoptotic pathway. We determined that CSE increases expression of caspase 3 and 8 cleavage in MRC-5 cells and overexpression of PKC-η significantly increased expression of caspase 3 and 8 cleavage compared with control LacZ-infected cells. In contrast, dominant negative (dn) PKC-η inhibited apoptosis in MRC-5 cells exposed to CSE and decreased expression of caspase 3 and 8 compared with control cells. Exposure to 10% CSE for >8 h significantly increased lactate dehydrogenase release in PKC-η-infected cells compared with LacZ-infected cells. Additionally, PKC-η-infected cells had an increased number of Hoechst 33342 stained nuclei compared with LacZ-infected cells, while dn PKC-η-infected cells exhibited fewer morphological changes than LacZ-infected cells under phase-contrast microscopy. In conclusion, PKC-η activation plays a pro-apoptotic role in CSE-induced extrinsic apoptotic pathway in MRC-5 cells. These results suggest that modulation of PKC-η may be a useful tool for regulating the extrinsic apoptosis of MRC-5 cells by CSE and may have therapeutic potential in the treatment of CS-induced lung injury.
authors.affiliation: Department of Pulmonary, Allergy and Critical Care Medicine, Gachon University, Gil Medical Center, Namdong-Gu, Incheon, Republic of Korea.
authors.forename: E S
authors.initials: ES
authors.lastname: Son
authors.affiliation: Department of Pulmonary, Allergy and Critical Care Medicine, Gachon University, Gil Medical Center, Namdong-Gu, Incheon, Republic of Korea.
authors.forename: S Y
authors.initials: SY
authors.lastname: Kyung
authors.affiliation: Department of Pulmonary, Allergy and Critical Care Medicine, Gachon University, Gil Medical Center, Namdong-Gu, Incheon, Republic of Korea.
authors.forename: S P
authors.initials: SP
authors.lastname: Lee
authors.affiliation: Department of Pulmonary, Allergy and Critical Care Medicine, Gachon University, Gil Medical Center, Namdong-Gu, Incheon, Republic of Korea.
authors.forename: S H
authors.initials: SH
authors.lastname: Jeong
authors.affiliation: Department of Pulmonary, Allergy and Critical Care Medicine, Gachon University, Gil Medical Center, Namdong-Gu, Incheon, Republic of Korea.
authors.forename: J Y
authors.initials: JY
authors.lastname: Shin
authors.affiliation: Institute of Molecular Oncology, Showa University, Hatanodai, Shinagawa-ku, Tokyo, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Ohba
authors.affiliation: Department of Biochemistry, School of Medicine, Gachon University, Yeonsu-Gu, Incheon, Republic of Korea.
authors.forename: E J
authors.initials: EJ
authors.lastname: Yeo
authors.affiliation: Department of Pulmonary, Allergy and Critical Care Medicine, Gachon University, Gil Medical Center, Namdong-Gu, Incheon, Republic of Korea jwpark@gilhospital.com.
authors.forename: J W
authors.initials: JW
authors.lastname: Park
mesh_terms: D017209:Apoptosis / Q000187:drug effects*; D053148:Caspase 3 / Q000378:metabolism; D053181:Caspase 8 / Q000378:metabolism; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D005347:Fibroblasts / Q000187:drug effects; D006801:Humans; D007770:L-Lactate Dehydrogenase / Q000378:metabolism; D007763:Lac Operon / Q000187:drug effects; D008168:Lung / Q000473:pathology; D011493:Protein Kinase C / Q000187:drug effects*; D029424:Pulmonary Disease, Chronic Obstructive / Q000473:pathology; D012906:Smoke / Q000009:adverse effects*; D014026:Nicotiana / Q000633:toxicity*; D001616:beta-Galactosidase / Q000378:metabolism
chemical_list: D012906:Smoke; D007770:L-Lactate Dehydrogenase; C081975:protein kinase C eta; D011493:Protein Kinase C; D001616:beta-Galactosidase; D053148:Caspase 3; D053181:Caspase 8
keywords: Apoptosis; chronic obstructive pulmonary disease; cigarette smoke; protein kinase C