The Mechanism Of Alliin Improving Lipid Accumulation Induced By 1,3-Dichloro-2-Propanol Via Activating Autophagy

Lipid metabolic disorders can lead to many systemic diseases.1,3-dichloro-2-propanol(1,3-DCP)is a food chemical pollutant.According to studies,1,3-DCP can induce abnormal accumulation of lipid in hepatocytes,leading to lipid metabolic disorders.Alliin is the main component of garlic.Alliin has been reported to have hepaticlipid-lowering action,but the molecular mechanism remains unclear.Autophagy is a ubiquitous lysosome degradation process in eukaryotic cells.Regulation and function between autophagy and lipid metabolism are similar.Recently,a large number of studies have confirmed that abnormal autophagy is closely related to lipid accumulation.Therefore,the main purpose of this study is to explore the protective effect of Alliin on 1,3-DCP-induced lipid accumulation and autophagy disorder,and to elucidate the relationship between autophagy and Alliin's improvement of 1,3-DCP-induced lipid accumulation.In this study,we explored the mechanism of Alliin activating autophagy and regulating lipid accumulation induced by 1,3-DCP.Alliin improved 1,3-DCP-induced lipid accumulation by activating autophagy via P53/AMPK/mTOR signaling pathway.This study was carried out at the following levels:(1)Establish a 1,3-DCP-induced lipid accumulation model in HepG2 cells to study the protective effect of Alliin on 1,3-DCP-induced lipid accumulation;(2)Study the effect of Alliin on 1,3-DCP-inhibited autophagy in HepG2 cells;(3)Study the role and regulatory mechanism of Alliin-activated autophagy in 1,3-DCP-induced lipid accumulation.The main research contents and results are as follows:(1)Alliin could improve 1,3-DCP-induced lipid accumulation in HepG2 cells.Alliin could protect 1,3-DCP-induced lipid accumulation by Oil Red O staining and total cholesterol(TC)and triglyceride(TG)content detection;Western Blot was used to detect intracellular related proteins to determine that Alliin could activate AMP-activated protein kinase(AMPK)phosphorylation inhibited by 1,3-DCP;Alliin significantly down-regulated the expression levels of sterol regulatory element binding protein(SREBP-1),sterol regulatory elements binding protein 2(SREBP-2),fatty acid synthase(FAS)and hydroxymethyl glutaric acid monoacyl coenzyme A reductase(HMGCR).The mRNAlevels of SREBP-1 and SREBP-2 and downstream target genes FAS and HMGCR were detected by qPCR.(2)Alliin could activate 1,3-DCP-inhibited autophagy through P53/AMPK/mTOR signaling pathway.The results of MDC staining,immunofluorescence staining,transmission electron microscopy,microtubule-associated protein 1 light chain 3(LC3)and P62/SQSTM1 showed that 1,3-DCP inhibited autophagy in HepG2 cells,while Alliin could activate 1,3-DCP-inhibited autophagy in HepG2 cells.Rapamycin could activate 1,3-DCP-inhibited autophagy in HepG2 cells by inhibiting mTOR activity.AMPK activator could activate 1,3-DCP-inhibited autophagy in HepG2 cells by activating AMPK activity.P53 activator could activate 1,3-DCP-inhibited autophagy in HepG2 cells by activating P53 activity.Thus,P53/AMPK/mTOR signaling pathway played an important role in 1,3-DCP inhibited autophagy in HepG2 cells.Western Blot was used to detect the expression of proteins in P53/AMPK/mTOR signaling pathway.The results showed that Alliin could activate autophagy 1,3-DCP inhibited autophagy via P53/AMPK/mTOR signaling pathwayin HepG2 cells.(3)Alliin could activate autophagy to improve 1,3-DCP-induced lipid accumulationthrough P53/AMPK/mTOR signaling pathway.HepG2 cells were pretreated with autophagy inhibitor 3-methyladenine(3-MA),then the effects of 3-MA on autophagy and lipid accumulation of HepG2 cells were analyzed by Oil Red O staining,TC,TG and Western Blot assay.The results showed that Alliin could improve 1,3-DCP-induced lipid accumulation in HepG2 cells by activating autophagy.HepG2 cells were pretreated with P53 siRNA,then the effects of P53/AMPK/mTOR signaling pathway on autophagy and lipid accumulation of HepG2 cells were analyzed by Oil Red O staining,TC,TG and Western Blot assay.The results showed that Alliin could activate autophagy to improve 1,3-DCP-induced lipid accumulation through P53/AMPK/mTOR signaling pathwayin HepG2 cells.In conclusion,this study elucidated that Alliin could improve the lipid accumulation induced by 1,3-DCP in HepG2 cells at the molecular level,such as protein and mRNA.It was revealed that 1,3-DCP inhibited autophagy in HepG2 cells through P53/AMPK/mTOR signaling pathway.Itwas proved that Alliin could activate 1,3-DCP-inhibited autophagy of HepG2 cells.Finally it was clarified that Alliin could activate autophagy to improve 1,3-DCP-induced lipid accumulationthrough P53/AMPK/mTOR signaling pathway.This study demonstrated that Alliin activated 1,3-DCP-inhibited autophagy and improved 1,3-DCP-induced lipid accumulation,which provided data support and experimental basis for the establishment of a new method for hazard control of 1,3-DCP and for the protection of 1,3-DCP exposure hazards by Alliin.It had important theoretical and practical significance.