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Mol. Cells 2012; 33(4): 343-350

Published online February 29, 2012

https://doi.org/10.1007/s10059-012-2172-x

© The Korean Society for Molecular and Cellular Biology

Nicotinic Acetylcholine Receptor α7 and β4 Subunits Contribute Nicotine-Induced Apoptosis in Periodontal Ligament Stem Cells

So Yeon Kim1, Kyung Lhi Kang2, Jeong-Chae Lee3,*, and Jung Sun Heo1,*

1Department of Maxillofacial Biomedical Engineering and Institute of Oral Biology, School of Dentistry, Kyung Hee University, Seoul 130-701, Korea, 2Department of Periodontology, School of Dentistry, Kyung Hee University, Seoul 130-701, Korea, 3Institute of Oral Biosciences, Cluster for Craniofacial Development and Regeneration Research and School of Dentistry (Brain Korea 21 Program), Chonbuk National University, Jeonju 561-756, Korea

Correspondence to : *Correspondence: heojs@khu.ac.kr (JSH); leejc88@jbnu.ac.kr (JCL)

Received: August 22, 2011; Revised: January 6, 2012; Accepted: January 18, 2012

Abstract

Nicotine, a major component of cigarette smoking, is the important risk factor for the development of periodontal disease. However, the mechanisms that underlie the cytotoxicity of nicotine in human periodontal ligament stem cells (PDLSCs) are largely unknown. Thus, the purpose of this study was to determine the cytotoxic effect of nicotine by means of nicotinic acetylcholine receptor (nAChR) activation in PDLSCs. We first detected alpha7 and beta4 nAChRs in PDLSCs. The gene expressions of alpha7 and beta4 nAChR were increased by nicotine administration. Nicotine significantly decreased cell viability at a concentration higher than 10-5 M. DNA fragmentation was also detected at high doses of nicotine treatment. Moreover, the detection of sub G1 phase and TUNEL assay demonstrated that nicotine significantly induced apoptotic cell death at 10-2 M concentration. Western blot analysis confirmed that p53 proteins were phosphorylated by nicotine. Under various doses of nicotine, a decrease in the anti-apoptotic pro-tein Bcl-2, but an increase in p53 and cleaved caspase-3 protein levels, was detected in a dose-dependent manner. However, the apoptotic effect of nicotine was inhibited by the pretreatment of alpha-bungarotoxin, a selective alpha7 nAChR antagonist or mecamylamine, a non-selective nAChR antagonist. Finally, increases in the subG1 phase and DNA fragmentation by nicotine was attenuated by each nAChR antagonist. Collectively, the presence of alpha7 and beta4 nAChRs in PDLSCs supports a key role of nAChRs in the modulation of nicotine-induced apoptosis.

Keywords apoptosis, nAChRs, nicotine, periodontal disease, periodontal ligament stem cells

Article

Research Article

Mol. Cells 2012; 33(4): 343-350

Published online April 30, 2012 https://doi.org/10.1007/s10059-012-2172-x

Copyright © The Korean Society for Molecular and Cellular Biology.

Nicotinic Acetylcholine Receptor α7 and β4 Subunits Contribute Nicotine-Induced Apoptosis in Periodontal Ligament Stem Cells

So Yeon Kim1, Kyung Lhi Kang2, Jeong-Chae Lee3,*, and Jung Sun Heo1,*

1Department of Maxillofacial Biomedical Engineering and Institute of Oral Biology, School of Dentistry, Kyung Hee University, Seoul 130-701, Korea, 2Department of Periodontology, School of Dentistry, Kyung Hee University, Seoul 130-701, Korea, 3Institute of Oral Biosciences, Cluster for Craniofacial Development and Regeneration Research and School of Dentistry (Brain Korea 21 Program), Chonbuk National University, Jeonju 561-756, Korea

Correspondence to:*Correspondence: heojs@khu.ac.kr (JSH); leejc88@jbnu.ac.kr (JCL)

Received: August 22, 2011; Revised: January 6, 2012; Accepted: January 18, 2012

Abstract

Nicotine, a major component of cigarette smoking, is the important risk factor for the development of periodontal disease. However, the mechanisms that underlie the cytotoxicity of nicotine in human periodontal ligament stem cells (PDLSCs) are largely unknown. Thus, the purpose of this study was to determine the cytotoxic effect of nicotine by means of nicotinic acetylcholine receptor (nAChR) activation in PDLSCs. We first detected alpha7 and beta4 nAChRs in PDLSCs. The gene expressions of alpha7 and beta4 nAChR were increased by nicotine administration. Nicotine significantly decreased cell viability at a concentration higher than 10-5 M. DNA fragmentation was also detected at high doses of nicotine treatment. Moreover, the detection of sub G1 phase and TUNEL assay demonstrated that nicotine significantly induced apoptotic cell death at 10-2 M concentration. Western blot analysis confirmed that p53 proteins were phosphorylated by nicotine. Under various doses of nicotine, a decrease in the anti-apoptotic pro-tein Bcl-2, but an increase in p53 and cleaved caspase-3 protein levels, was detected in a dose-dependent manner. However, the apoptotic effect of nicotine was inhibited by the pretreatment of alpha-bungarotoxin, a selective alpha7 nAChR antagonist or mecamylamine, a non-selective nAChR antagonist. Finally, increases in the subG1 phase and DNA fragmentation by nicotine was attenuated by each nAChR antagonist. Collectively, the presence of alpha7 and beta4 nAChRs in PDLSCs supports a key role of nAChRs in the modulation of nicotine-induced apoptosis.

Keywords: apoptosis, nAChRs, nicotine, periodontal disease, periodontal ligament stem cells

Mol. Cells
Mar 31, 2023 Vol.46 No.3, pp. 131~189
COVER PICTURE
The physiologically important cytoprotective signaling in normal cells (background area in turquoise) mediated by NRF2 (blue chain) is often hijacked by cancer cells (red ball) in the tumor microenvironment (yellow area). However, the differential roles of NRF2 throughout the multistage carcinogenesis remains largely unresolved (white-colored overlapping misty areas).

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