Rab18 Down-regulates PLIN2 Via Regulating The JAK2/STAT3 Signaling Pathway To Reduce Lipid Accumulation In Macrophages

[AIM] The purpose of this study was to investigate whether Rab18 can inhibit lipid accumulation in macrophages by regulating the JAK2/STAT3 signaling pathway to reduce PLIN2 expression.[Methods]50μg/mL ox-LDL was used to treat THP-1 macrophages at different time periods(0h,6h,12 h,24h),and Western blot was used to detect the protein expression levels of Rab18,JAK2,STAT3,PLIN2 and p JAK2/JAK2,p STAT3/STAT3.The Rab18(Q67L),Rab18(S22N),Rab18(WT)plasmids were transfected into macrophages to prepare highly active,wild-type,inactive Rab18 cells,and then the transfected cells were treated with 50μg/ m L ox-LDL for 24 h,the cells were divided into Control group,HA group(highly active RAB18),WT group(wild-type RAB18)and LA group(inactivated RAB18).the m RNA and protein expressions of Rab18,JAK2,STAT3 and PLIN2 were detected by RT-q PCR and Western Blot,and the changes of p JAK2/JAK2 and p STAT3/STAT3 were detected by Western Blot.Rab18 co-localization with JAK2 and STAT3 and the effect of Rab18 on p-JAK2 and p-STAT3 nuclear translocation were detected by immunofluorescence.The content of triglyceride and lipid accumulation were respectively detected by GPO-PAP enzyme and oil red O staining.THP-1 macrophages were treated with 50μmol/L AG490 for16 h,the cells were divided into Control group,HA group and HA+AG490group.The m RNA and protein expression of JAK2,STAT3 and PLIN2 were detected by RT-q PCR and Western blot,and the changes of p JAK2/JAK2 and p STAT3/STAT3 were detected by Western Blot.The fluorescence intensity of Plin2 in cells was observed by immunofluorescence.Lipid accumulation was observed by oil red O staining in THP-1 macrophages.GPO-PAP enzyme was used to detect the changes of intracellular TG content.[Results] The expression of RAB18,JAK2,p JAK2,STAT3,p STAT3 and PLIN2 were increased after pretreatment of ox-LDL at 50mg/L for 24 h.Compared with 0h,the difference is significant(P<0.05),and lipid accumulation in cells was increased.The protein expression of Rab18 in HA,WT and LA group were significantly increased compared with the Control group.The changes of JAK2,STAT3,p JAK2,p STAT3,p JAK2/JAK2 and p STAT3/STAT3 in HA and WT groups were significantly increased(P<0.05).The protein expression levels of PLIN2 and the content of triglyceride were decreased in HA and WT groups.The colocalization of Rab18 and JAK2,STAT3 were observed by immunofluorescence.Compared with Control group,the expression of p JAK2 and p STAT3 were increased in HA group,and p STAT3 showed nuclear translocation.Compared with HA group,the expressions of JAK2,p JAK2,STAT3,p STAT3,p JAK2 /JAK2,p STAT3 /STAT3 in HA+AG490group were decreased,while the content of triglyceride,PLIN2 expression and lipid accumulation were increased.[Conclusion] Rab18 down-regulates PLIN2 via regulating the JAK2/STAT3 signaling pathway to reduce lipid accumulation in macrophages...