AIM:To explore whether microRNA-30a-3p(miR-30a-3p)is involved in the pathogenesis of non-alcoholic fatty liver disease(NAFLD)by regulating autophagy and promoting lipid deposition.METHODS:Eight-week-old C57BL/6 mice were randomly divided into a normal control group and a high-fat diet(HFD)group.Mice in the HFD group were fed with 60％high fat diet for 10 weeks to induce the NAFLD phenotype.Some mice were injected with adeno-virus overexpressing miR-30a-3p via the tail vein and subsequently fed with high-fat diet for 4 weeks.Glucose tolerance and insulin resistance tests were performed at the end of the treatments.In addition,the concentrations of hepatic alanine aminotransferase(ALT),aspartate aminotransferase(AST),triglyceride(TG)and total cholesterol(TC)were mea-sured.Hematoxylin-eosin staining and oil red O staining were conducted to examine morphological changes and lipid depo-sition in the liver tissue.The expression levels of microtubule-associated protein light chain 3(LC3),autophagy-related protein 5(ATG5),beclin-1 and p62 were quantified through Western blot.In addition,NAFLD models were established in AML12 hepatocytes by incubating the cells with palmitic acid and oleic acid(PO).The AML12 cells were transfected with miR-30a-3p shRNA to knock down miR-30a-3p expression.The concentration levels of TG and TC after miR-30a-3p knockdown were measured by the kits.Nile red staining was performed to examine lipid droplet aggregation and dual fluo-rescent recombinant adenovirus Ad-mCherry-GFP-LC3B was transfected into AML12 cells to observe changes in autopha-gic flow.RESULTS:HFD-fed mice exhibited significant insulin resistance and reduced glucose tolerance,significant lip-id deposition in the liver tissue,coupled with increased hepatic ALT,AST,TG and TC levels.The expression levels of au-tophagy-related proteins LC3-Ⅱ,beclin-1,and ATG5 were decreased,while that of p62 was increased(P<0.01).More-over,miR-30a-3p overexpression significantly increased blood glucose and insulin resistance in HFD-fed mice.However,it aggravated lipid droplets deposition in liver tissue and enhanced hepatic TG,TC,AST and ALT levels.Western blot re-vealed that the expression levels of LC3-Ⅱ,beclin-1 and ATG5 were further reduced,while that of p62 was significantly in-creased(P<0.01).In vitro,we observed that the TG and TC levels,as well as lipid accumulation in PO-treated AML12 cells were increased significantly.Similarly,the expression levels of LC3-Ⅱ,beclin-1 and ATG5 were decreased,whereas that of p62 increased in PO-treated AML12 cells(P<0.01).Notably,knockdown of miR-30a-3p resulted in a significant reduction in the TG content in PO-treated AML12 cells and lipid droplet aggregation was significantly suppressed.Further-more,the expression of LC3-Ⅱ,beclin-1 and ATG5 proteins was increased,while that of p62 was decreased significantly and the autophagy flow was improved(P<0.01).CONCLUSION:The miR-30a-3p exacerbates hepatic lipid deposi-tion,inducing severe hepatic steatosis and liver damage,to promote the occurrence and development of NAFLD in mice.Mechanistically,its effects involve inhibition of hepatic autophagy level.

AIM:To explore whether microRNA-30a-3p(miR-30a-3p)is involved in the pathogenesis of non-alcoholic fatty liver disease(NAFLD)by regulating autophagy and promoting lipid deposition.METHODS:Eight-week-old C57BL/6 mice were randomly divided into a normal control group and a high-fat diet(HFD)group.Mice in the HFD group were fed with 60％high fat diet for 10 weeks to induce the NAFLD phenotype.Some mice were injected with adeno-virus overexpressing miR-30a-3p via the tail vein and subsequently fed with high-fat diet for 4 weeks.Glucose tolerance and insulin resistance tests were performed at the end of the treatments.In addition,the concentrations of hepatic alanine aminotransferase(ALT),aspartate aminotransferase(AST),triglyceride(TG)and total cholesterol(TC)were mea-sured.Hematoxylin-eosin staining and oil red O staining were conducted to examine morphological changes and lipid depo-sition in the liver tissue.The expression levels of microtubule-associated protein light chain 3(LC3),autophagy-related protein 5(ATG5),beclin-1 and p62 were quantified through Western blot.In addition,NAFLD models were established in AML12 hepatocytes by incubating the cells with palmitic acid and oleic acid(PO).The AML12 cells were transfected with miR-30a-3p shRNA to knock down miR-30a-3p expression.The concentration levels of TG and TC after miR-30a-3p knockdown were measured by the kits.Nile red staining was performed to examine lipid droplet aggregation and dual fluo-rescent recombinant adenovirus Ad-mCherry-GFP-LC3B was transfected into AML12 cells to observe changes in autopha-gic flow.RESULTS:HFD-fed mice exhibited significant insulin resistance and reduced glucose tolerance,significant lip-id deposition in the liver tissue,coupled with increased hepatic ALT,AST,TG and TC levels.The expression levels of au-tophagy-related proteins LC3-Ⅱ,beclin-1,and ATG5 were decreased,while that of p62 was increased(P<0.01).More-over,miR-30a-3p overexpression significantly increased blood glucose and insulin resistance in HFD-fed mice.However,it aggravated lipid droplets deposition in liver tissue and enhanced hepatic TG,TC,AST and ALT levels.Western blot re-vealed that the expression levels of LC3-Ⅱ,beclin-1 and ATG5 were further reduced,while that of p62 was significantly in-creased(P<0.01).In vitro,we observed that the TG and TC levels,as well as lipid accumulation in PO-treated AML12 cells were increased significantly.Similarly,the expression levels of LC3-Ⅱ,beclin-1 and ATG5 were decreased,whereas that of p62 increased in PO-treated AML12 cells(P<0.01).Notably,knockdown of miR-30a-3p resulted in a significant reduction in the TG content in PO-treated AML12 cells and lipid droplet aggregation was significantly suppressed.Further-more,the expression of LC3-Ⅱ,beclin-1 and ATG5 proteins was increased,while that of p62 was decreased significantly and the autophagy flow was improved(P<0.01).CONCLUSION:The miR-30a-3p exacerbates hepatic lipid deposi-tion,inducing severe hepatic steatosis and liver damage,to promote the occurrence and development of NAFLD in mice.Mechanistically,its effects involve inhibition of hepatic autophagy level.

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