Xiaokeping-induced autophagy protects pancreaticβ-...

Xiaokeping-induced autophagy protects pancreaticβ-cells against apoptosis under high glucose stress

Yanyang Wua，b，c，d 　Yongquan Hua 　Haiyan Zhoua 　YunLin Weie 　Xincong Kanga 　Dongbo Liua，b，c，d

a.Hunan Agricultural University，Changsha，410128，Hunan，PR China；

b.Hunan Provincial Key Laboratory of Crop Germplasm Innovation and Utilization，Hunan Agricultural University，Changsha，410128，Hunan，PR China；

c.Hunan Co-Innovation Center for Utilization of Botanical Functional Ingredients，Changsha，410128，Hunan，PR China；(https://www.daowen.com)

d.State Key Laboratory of Subhealth Intervention Technology，Changsha，410128，Hunan，PR China；

e.Kunming University of Science and Technology，Yunnan，PR China

Abstract：Xiaokeping(XKP)，a prescribed Traditional Chinese Medicine(TCM)，has been used to treat patients with typeⅡdiabetes mellitus for many years；however，the molecular mechanism of its effects is unknown.As the only insulin producer，the pancreaticβ-cell plays an important role in diabetes.Whether XKP influences the viability of pancreaticβ-cells remains to be substantiated.In the present study，autophagy/apoptosis analyses were used to evaluate the therapeutic effect of XKPon pancreaticβ-cells induced by high glucose levels and to investigate a potential causal molecular mechanism of XKPeffect on the cells.The pancreaticβ-cell lines MIN-6 were divided into four groups：control，high glucose(33.3mmol/L)，high glucose with XKP，high glucose with XKP and 3-Methyladenine(3-MA).Immunofluorescence assay was employed to determine autophagosome formation and flow cytometry was used to determine apoptotic rates of theβ-cells by the detecting expression of autophagyand apoptosis-related proteins.High glucose increased the apoptotic rate ofβ-cells from 5.37% to 23.24%；however addition of XKP mitigated the rate at 10.92%.Data indicate that autophagy ofβ-cells was induced by XKP via the mammalian target of rapamycin(mTOR)pathway.Where the autophagy inhibitor 3-MA was added，the apoptotic rate was 23.94%，similar to the high glucose group rate.The results suggest a potential cytoprotective effect of XKP from high glucose toxicity by its induction of autophagy which may be linked to mTORmediated autophagy.

Keywords：autophagy，apoptosis，β-cells，high glucose