摘要Anterior gradient 2(AGR2),a protein disulfide isomerase(PDI),is a multifunctional protein under physiological and pathological conditions.In this study we investigated the roles of AGR2 in regulating cholesterol biogenesis,lipid-lowering efficiency of lovastatin as well as in protection against hypercholesterolemia/statin-induced liver injury.We showed that AGR2 knockout significantly decreased hepatic and serum total cholesterol(TC)and low-density lipoprotein cholesterol(LDL-C)in mice with whole-body or hepatocyte-specific Agr2-nulll mutant,compared with the levels in their wild-type littermates fed a normal chow diet(NCD)or high-fat diet(HFD).In contrast,mice with AGR2 overexpression(Agr2/Tg)exhibited an increased cholesterol level.Mechanistic studies revealed that AGR2 affected cholesterol biogenesis via activation of AKT/sterol regulatory element-binding protein-2(SREBP2),to some extent,in a PDI motif-dependent manner.Moreover,elevated AGR2 led to a significant decrease in the lipid-lowering efficacy of lovastatin(10mg·kg-1·d-1,ip,for 2 weeks)in mice with hypercholesterolemia(hyperCho),which was validated by results obtained from clinical samples in statin-treated patients.We showed that lovastatin had limited effect on AGR2 expression,but AGR2 was inducible in Agr2/Tg mice fed a HFD.Further investigations demonstrated that drug-induced liver toxicity and inflammatory reactions were alleviated in hypercholesterolemic Agr2/Tg mice,suggesting the dual functions of AGR2 in lipid management and hyperCho/statin-induced liver injury.Importantly,the AGR2-reduced lipid-lowering efficacy of lovastatin was attenuated,at least partially,by co-administration of a sulfhydryl-reactive compound allicin(20 mg·kg-1·d-1,ip,for 2 weeks).These results demonstrate a novel role of AGR2 in cholesterol metabolism,drug resistance and liver protection,suggesting AGR2 as a potential predictor for selection of lipid-lowering drugs in clinic.