Diabetes inhibits corneal epithelial cell migration and tight junction formation in mice and human via increasing ROS and impairing Akt signaling

Authors: Qi-wei Jiang1,2, Denis Kaili1, Jonaye Freeman1, Chong-yang Lei1, Bing-chuan Geng1, Tao Tan1, Jian-feng He3, Zhi Shi2, Jian-jie Ma1, Yan-hong Luo3, Heather Chandler4, Hua Zhu1
1 Department of Surgery, The Ohio State University Wexner Medical Center, Columbus, OH 43210, USA
2 Department of Cell Biology & Institute of Biomedicine, National Engineering Research Center of Genetic Medicine, Provincial Key Laboratory of Bioengineering Medicine, College of Life Science and Technology, Jinan University, Guangzhou 510632, China
3 Department of Endocrinology, Children’s Hospital Chongqing Medical University, Chongqing 400016, China
4 College of Optometry, The Ohio State University, Columbus, OH 43210, USA
Correspondence to: Yan-hong Luo:, Heather Chandler:, Hua Zhu:,
DOI: 10.1038/s41401-019-0223-y
Received: 18 December 2018
Accepted: 21 February 2019
Advance online: 13 March 2019


Corneal wounds usually heal quickly; but diabetic patients have more fragile corneas and experience delayed and painful healing. In the present study, we compared the healing capacity of corneal epithelial cells (CECs) between normal and diabetic conditions and the potential mechanisms. Primary murine CEC derived from wild-type and diabetic (db/db) mice, as well as primary human CEC were prepared. Human CEC were exposed to high glucose (30 mM) to mimic diabetic conditions. Cell migration and proliferation were assessed using Scratch test and MTT assays, respectively. Reactive oxygen species (ROS) production in the cells was measured using dichlorofluorescein reagent. Western blot was used to evaluate the expression levels of Akt. Transepithelial electrical resistance (TEER) and zonula occludens-1 (ZO-1) expression were used to determine tight junction integrity. We found that the diabetic CEC displayed significantly slower cell proliferation and migration compared with the normal CEC from both mice and humans. Furthermore, ROS production was markedly increased in CEC grown under diabetic conditions. Treatment with an antioxidant N-acetyl cysteine (NAC, 100 μM) significantly decreased ROS production and increased wound healing in diabetic CEC. Barrier function was significantly reduced in both diabetic mouse and human CEC, while NAC treatment mitigated these effects. We further showed that Akt signaling was impaired in diabetic CEC, which was partially improved by NAC treatment. These results show that diabetic conditions lead to delayed wound-healing capacity of CEC and impaired tight junction formation in both mice and human. Increased ROS production and inhibited Akt signaling may contribute to this outcome, implicating these as potential targets for treating corneal wounds in diabetic patients.
Keywords: diabetes; corneal epithelial cells; healing capacity; cell migration; cell proliferation; ROS; N-acetyl cysteine; Akt signaling

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