title: The key role of miR-21-regulated SOD2 in the medium-mediated bystander responses in human fibroblasts induced by α-irradiated keratinocytes.
abstract: Radiation-induced bystander effect (RIBE) is well accepted in the radiation research field by now, but the underlying molecular mechanisms for better understanding this phenomenon caused by intercellular communication and intracellular signal transduction are still incomplete. Although our previous study has demonstrated an important role of miR-21 of unirradiated bystander cells in RIBEs, the direct evidence for the hypothesis that RIBE is epigenetically regulated is still limited and how miR-21 mediates RIBEs is unknown. Reactive oxygen species (ROS) have been demonstrated to be involved in RIBEs, however, the roles of anti-oxidative stress system of cells in RIBEs are unclear. Using transwell insert co-culture system, we investigated medium-mediated bystander responses in WS1 human fibroblasts after co-culture with HaCaT keratinocytes traversed by α-particles. Results showed that the ROS levels in unirradiated bystander WS1 cells were significantly elevated after 30min of co-culture, and 53BP1 foci, a surrogate marker of DNA damage, were obviously induced after 3h of co-culture. This indicates the occurrence of oxidative stress and DNA damage in bystander WS1 cells after co-culture with irradiated keratinocytes. Furthermore, the expression of miR-21 was increased in bystander WS1 cells, downregulation of miR-21 eliminated the bystander responses, overexpression of miR-21 alone could induce bystander-like oxidative stress and DNA damage in WS1 cells. These data indicate an important mediating role of miR-21 in RIBEs. In addition, MnSOD or SOD2 in WS1 cells was involved in the bystander effects, overexpression of SOD2 abolished the bystander oxidative stress and DNA damage, indicating that SOD2 was critical to the induction of RIBEs. Moreover, we found that miR-21 regulated SOD2, suggesting that miR-21 might mediate bystander responses through its regulation on SOD2. In conclusion, this study revealed a profound role of miR-21-regulated SOD2 of unirradiated WS1 cells in bystander effects induced by α-irradiated HaCaT keratinocytes.
authors: School of Radiation Medicine and Protection, Medical College of Soochow University/Collaborative Innovation Center of Radiation Medicine of Jiangsu Higher Education Institutions, 199 Renai Road, Suzhou Industrial Park, Suzhou, Jiangsu Province 215123, PR China.
authors: Wenqian
authors: W
authors: Tian
authors: School of Radiation Medicine and Protection, Medical College of Soochow University/Collaborative Innovation Center of Radiation Medicine of Jiangsu Higher Education Institutions, 199 Renai Road, Suzhou Industrial Park, Suzhou, Jiangsu Province 215123, PR China.
authors: Xiaoming
authors: X
authors: Yin
authors: School of Radiation Medicine and Protection, Medical College of Soochow University/Collaborative Innovation Center of Radiation Medicine of Jiangsu Higher Education Institutions, 199 Renai Road, Suzhou Industrial Park, Suzhou, Jiangsu Province 215123, PR China.
authors: Longxiao
authors: L
authors: Wang
authors: School of Radiation Medicine and Protection, Medical College of Soochow University/Collaborative Innovation Center of Radiation Medicine of Jiangsu Higher Education Institutions, 199 Renai Road, Suzhou Industrial Park, Suzhou, Jiangsu Province 215123, PR China.
authors: Jingdong
authors: J
authors: Wang
authors: School of Radiation Medicine and Protection, Medical College of Soochow University/Collaborative Innovation Center of Radiation Medicine of Jiangsu Higher Education Institutions, 199 Renai Road, Suzhou Industrial Park, Suzhou, Jiangsu Province 215123, PR China.
authors: Wei
authors: W
authors: Zhu
authors: School of Radiation Medicine and Protection, Medical College of Soochow University/Collaborative Innovation Center of Radiation Medicine of Jiangsu Higher Education Institutions, 199 Renai Road, Suzhou Industrial Park, Suzhou, Jiangsu Province 215123, PR China.
authors: Jianping
authors: J
authors: Cao
authors: School of Radiation Medicine and Protection, Medical College of Soochow University/Collaborative Innovation Center of Radiation Medicine of Jiangsu Higher Education Institutions, 199 Renai Road, Suzhou Industrial Park, Suzhou, Jiangsu Province 215123, PR China; Institute of Radiotherapy & Oncology, Soochow University. Electronic address: yanghongying@suda.edu.cn.
authors: Hongying
authors: H
authors: Yang
mesh_terms: D000512:Alpha Particles / Q000009:adverse effects*; D024201:Bystander Effect / Q000235:genetics / Q000528:radiation effects*; D002461:Cell Line, Transformed; D018920:Coculture Techniques; D004249:DNA Damage; D005347:Fibroblasts / Q000378:metabolism* / Q000473:pathology; D015971:Gene Expression Regulation, Enzymologic / Q000235:genetics / Q000528:radiation effects*; D006801:Humans; D015603:Keratinocytes / Q000378:metabolism* / Q000473:pathology; D035683:MicroRNAs / Q000235:genetics / Q000378:metabolism*; D018384:Oxidative Stress / Q000235:genetics / Q000528:radiation effects; D017382:Reactive Oxygen Species / Q000378:metabolism; D013482:Superoxide Dismutase / Q000096:biosynthesis* / Q000235:genetics; D000099156:Superoxide Dismutase 2
chemical_list: D035683:MicroRNAs; D017382:Reactive Oxygen Species; D013482:Superoxide Dismutase; D000099156:Superoxide Dismutase 2; C524940:MIRN21 microRNA, human
keywords: Fibroblasts; Keratinocytes; Radiation-induced bystander effect; SOD2; miR-21; α-Particles