Effect Of Irisin On The Function And Apoptosis Of INS-1 Cells Induced By PA Through Autophagy

Objective: 1.To investigate the effect of irisin on autophagy of INS-1 cells induced by PA;2.To investigate whether irisin affects the secretion function and apoptosis of INS-1 cells by affecting the autophagy level of INS-1 cells induced by PA.Methods:INS-1 cells were cultured and divided into six groups: normal group,PA group,PA + 100 ng/ml irisin group(PA + I1),PA + 500 ng/ml irisin group(PA + I2),PA + 1000 ng/ml irisin group(PA + I3),PA + 1500 ng/ml irisin group(PA + I4).The autophagy related proteins p-mTOR/mTOR,p62,LC3 II,LC3I were observed by Western blot,The level of LC3II/I showed that irisin could affect the autophagy level of INS-1 cells interfered by PA,and the best concentration of irisin was selected.In order to observe whether irisin can affect insulin secretion and apoptosis of INS-1 cells by autophagy,INS-1 cells were divided into normal group,PA group,PA + 1500ng/ml irisin group,PA + 1500ng/ml irisin + rapamycin group and PA + 1500ng/ml irisin + 3-MA group.The levels of insulin secretion,protein levels of p-mTOR,mTOR,p62,LC3 II and LC3 I were detected by Western blot,autophagy flow and apoptosis level were detected by mRFP-GFP-LC3 adenovirus transfection and flow cytometry respectively.Results:Compared with the normal group,the ratio of LC3II/I in the PA group was higher [(0.745±0.035)vs.(1.015±0.012),P=0.000].With the increase of irisin concentration,the level of LC3II/I increased gradually and had statistical significance(I1 1.465±0.028,I2 2.269±0.063,I3 1.858±0.074,I4 2.355±0.074,P=0.000,P=0.000,P=0.000,P=0.000).When irisin concentration was 1500ng/mL,the level of LC3II/I was the highest.PA group had significantly reduced GSIS levels in the INS-1 cell supernatant compared with the normal group,while the irisin treated group had increased GSIS levels than the PA group[(0.138±0.012)ng/ml vs.(0.322±0.041)ng/ml,P=0.001;(0.245±0.043)ng/ml vs.(0.414±0.036)ng/ml,P=0.005].The PA group had a significantly higher number of autophagosome than the normal group[(2.33±1.53)vs.(10.33±1.53),P=0.000],but there was no obvious change in the number of autolysosome[(2.33±1.53)vs.(3.33±1.53),P=0.939].In the irisin group,the autolysosome number increased compared with PA group[(3.33±1.53)vs.(12±2.00),P=0.001].Treated with PA 24 hours,the apoptosis rate of INS-1 cells increased than the normal group[(11.417 ±1.297)vs.(46.507±0.525),P=0.000],while the irisin-treated group had a significantly reduced apoptosis rate with the PA group[(46.507±0.525)vs.(33.767±1.083),P=0.000].Conclusion:Irisin can affect the autophagy level of INS-1 cells induced by PA,and irisin can affect the autophagy level by acting on the formation of autophagy lysosomes,so as to improve the insulin secretion function and apoptosis level of INS-1 cells induced by PA.