Role of endoplasmic reticulophagy in interstitial cells of Cajal injury induced by endoplasmic reticulum stress

ZHANG Limin; LING Jianghong; ZHOU Zhou; XU Kuan; ZHANG Yuqin; XIE Tianyi; WANG Yujiao

doi:10.3969/j.issn.1002-266X.2018.09.007

Abstract：Objective To explore the role of endoplasmic reticulophagy (ER-phagy) during endoplasmic reticulum stress (ERS) induced by tunicamycin (TM) in rat interstitial cells of Cajal (ICCs),and to provide new targets for improving gastric motility disorders.Methods ICCs were isolated by collagenase digestion and identified by immunofluorescence staining.Tunicamycin (TM) was used to induce ICCs to establish ERS models,the 3-methyladenine (3-MA) was used to block autophagy,while the rapamycin (Rapa) was used to promote autophagy.Then the ICCs were randomly divided into 4 groups and received different interventions,including ICCs group (normal culture),ERS group (the ICCs were stimulated with 2 μg/mL TM),3-MA group (the ICCs were co-stimulated with 2 μg/mL TM and 4 μmol/mL 3-MA),and Rapa group (the ICCs were co-stimulated with 2 μg/mL TM and 2 μmol/mL Rapa);the ICCs in all groups were treated for 6 h.The mRNA expression levels of GRP78 (ERS biomarker) and LC3B (autophagy biomarker) were detected by real-time fluorescent quantitative PCR,and the activity of ICCswas detected by CCK-8 assay.Results We isolated and identifiedICCs successfully.Compared with the ICCs group,the mRNA expression levels of GRP78 and LC3B increased,and the activity of ICCs decreased in the ERS group,3-MA group,and Rapa group (all P ＜ 0.05).Compared with the ERS group,the mRNA expression of GRP78 increased,the mRNA expression of LC3B and the activity of ICCs decreased in the 3-MA group (all P ＜0.05);on the contrary,the mRNA expression of GRP78 decreased,the mRNA expression of LC3B,and the activity of ICCs increased in the Rapa group (all P ＜ 0.05).Conclusion ER-phagy occurs in the process of ERS of ICCs,and ER-phagy can reduce the ERS injury of ICCs.