Yequan Huang1, Weiwei Qiao1, Xinhuan Wang1, Qian Gao1, Yao Peng1, Zhuan Bian2, Liuyan Meng3. 1. The State Key Laboratory Breeding Base of Basic Science of Stomatology (Hubei-MOST) and Key Laboratory of Oral Biomedicine Ministry of Education, School and Hospital of Stomatology, Wuhan University, 237 Luoyu Road, Wuhan, 430079, Hubei, People's Republic of China. 2. The State Key Laboratory Breeding Base of Basic Science of Stomatology (Hubei-MOST) and Key Laboratory of Oral Biomedicine Ministry of Education, School and Hospital of Stomatology, Wuhan University, 237 Luoyu Road, Wuhan, 430079, Hubei, People's Republic of China. bianzhuan@whu.edu.cn. 3. The State Key Laboratory Breeding Base of Basic Science of Stomatology (Hubei-MOST) and Key Laboratory of Oral Biomedicine Ministry of Education, School and Hospital of Stomatology, Wuhan University, 237 Luoyu Road, Wuhan, 430079, Hubei, People's Republic of China. mengliuyan@whu.edu.cn.
Abstract
AIM: The study aimed to investigate the effects of DNA repair proteins on cell apoptosis in human DPSCs during inflammation. METHODS: Lipopolysaccharide (LPS) was used to stimulate inflammation in dental pulp in vivo and in vitro. We identified the activation of DSB response and DNA repair proteins in inflamed pulp tissue and in LPS-treated human DPSCs. Then we transfected the cells with Ku70 (a key protein involved in NHEJ) siRNA and detected the expression changes of γ-H2A.X, DNA repair proteins and cell apoptosis. RESULTS: Immunohistochemical staining showed that at 4 and 6 days of pulpitis the expression of Ku70 and γ-H2A.X significantly increased. The levels of γ-H2A.X, Ku70, Xrcc4, and Rad51 increased considerably in the LPS-treated DPSCs. Furthermore, decreased expression of Ku70 could increase the number of γ-H2A.X foci, apoptotic cells and reduce cell viability in DPSCs. CONCLUSIONS: The results indicate that NHEJ pathway was the main mechanism involved in DNA damage response induced by repeated LPS stimulation in DPSCs. Meanwhile, the findings suggested that Ku70 serves importantly in the apoptosis of DPSCs in the inflammatory environment.
AIM: The study aimed to investigate the effects of DNA repair proteins on cell apoptosis in human DPSCs during inflammation. METHODS:Lipopolysaccharide (LPS) was used to stimulate inflammation in dental pulp in vivo and in vitro. We identified the activation of DSB response and DNA repair proteins in inflamed pulp tissue and in LPS-treated human DPSCs. Then we transfected the cells with Ku70 (a key protein involved in NHEJ) siRNA and detected the expression changes of γ-H2A.X, DNA repair proteins and cell apoptosis. RESULTS: Immunohistochemical staining showed that at 4 and 6 days of pulpitis the expression of Ku70 and γ-H2A.X significantly increased. The levels of γ-H2A.X, Ku70, Xrcc4, and Rad51 increased considerably in the LPS-treated DPSCs. Furthermore, decreased expression of Ku70 could increase the number of γ-H2A.X foci, apoptotic cells and reduce cell viability in DPSCs. CONCLUSIONS: The results indicate that NHEJ pathway was the main mechanism involved in DNA damage response induced by repeated LPS stimulation in DPSCs. Meanwhile, the findings suggested that Ku70 serves importantly in the apoptosis of DPSCs in the inflammatory environment.
Entities:
Keywords:
DNA double-strand breaks; Homologous recombination; Lipopolysaccharide; Non-homologous end joining; Pulp stem cells; γ-H2A.X
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