3β-hydroxysteroid-△24 Reductase Through Scavenging Active Oxygen Protect Beta Cells From The Cell Apoptosis Caused By Endoplasmic Reticulum Stress

In this study,our research is mainly focus on the molecular mechanism of resisting ER stress from a novel protein DHCR24 which can be objective to the cell apoptosis in MIN6 cell line.Our strategy is to overexpress(adenovirus)and knock down(SiRNA)the DHCR24 in the Min6 cell line which is induced by tunicamycin to cause ER stress to change the level of the DHCR24 protein.After transfection,the degree of the cell apoptosis was detected using TUNEL and cell immunofluorescence techniques.The result indicates that when DHCR24 protein is overexpressed in MIN6 with adenovirus transfection,the degree of the cell apoptosis resulted from ER stress was effectively decreased.Based on the previous research,we did more work on the molecular mechanism of DHCR24 inhibition MIN6 apoptosis caused by ER stress.Western Blot analysis shows that under ER stress,when transfected with Ad-DHCR24 and Ad-LacZ,the expression level of molecular chaperones protein Bip increases demonstrate that ER stress take place in two groups of cell.It is reported that the high and lasting expression level of ATF6 and Cleaved-ATF6 promotes modulation of the ER stress.Therefore,we analyse the expression level of ATF6 and cleaved-ATF6 in MIn6 cell line transfected with Ad-DHCR24.As is shown,these two proteins in Min6(Ad-DHCR24)enjoy a high and lasting expression level.T hese data shows that DHCR24 can resist ER stress by influencing relative proteins which are responsible for the ER initiating.And then our research is concentrated on the mechanism of how DHCR24 affect the ER-related proteins function to resist ER stress.Previous study has shown that DHCR24 can catalyze δ-24 sites double-bond of the chain sterol back to a single-bond thus promoting synthesis of cholesterol.Meanwhile,DHCR24 can also eliminate the intracellular active oxygen.So we evaluate the expression level of cholesterol of the MIN 6 cell line with and without transfected with DHCR24.As a consequence,there is almost no significant difference between experimental group and control group.Finally,under ER,we measured the level of the active oxygen in MIN 6 cell line transfected with and without DHCR24 utilizing active oxygen fluorescent probe.The result indicates that the level of the active oxygen of the group in which DHCR24 is overexpressed is far below than control.All of these suggests that DHCR24 can resist ER stress by eliminating the overplus active oxygen and then attenuates the degree of ER stress resulted from cell oxidative stress,thus leaving cell enough time to modulate self metabolism,preventing the cell from apoptosis.