The Mechanism Of Hepatic Exosome-derived MiR-130a On Regulating Glucose And Lipid Metabolism In Adipocyte

As the main glucose and lipid metabolism site in the animal body,liver and adipose tissue have mutual information transmission and mutual regulation effect on each other,which not only maintains the homeostasis of energy metabolism of the animal body,but also ensures the healthy growth and development of animal.Currently,studies related the liver’s remote regulation of fat are mainly focused on hormones or liver factors.As efficient carriers of information communication among tissues,the exosomes play a role in liver fat crosstalk.Accordingly,the investigation of liver exosomes on the regulation of adipose tissue glucose and lipid metabolism is of great significance to human health and animal production.Studies have shown miR-130 a can participate in glucose and lipid metabolism.miR-130a-3p is the main regulatory vector.However,it is unclear whether miR-130a-3p derived from liver exosomes can regulate fatty lipids.Therefore,we investigated the effects of hepatic exosomes miR-130a-3p on glucose and lipid metabolism in adipose tissue.First,using mouse adipose precursor cells 3T3-L1 as a model,the effects of miR-130a-3p on adipocyte differentiation and lipid anabolic metabolism were verified.Then hepatic exosomes were extracted from wild-type mice,and mice which were systematically knockout miR-130a-3p(130KO)or overexpressed miR-130a-3p(130OE).On the one hand,three different types of hepatic exosomes(WT-EXO,KO-EXO,OE-EXO)were used to study lipid droplet formation,fat synthesis-related protein expression,carbohydrate absorption,and GLUT4 protein in 3T3-L1 cells.On the other hand,using 130 KO mice as a living model(FVB),three different hepatic exosomes were injected through the tail vein to study the effects of hepatic exosomes on mouse growth,fat deposition,oxidative respiratory metabolism,and glucose transport metabolism.The results of study:1.miR-130a-3p can significantly inhibit lipid droplet formation and triglyceride content in 3T3-L1 cells by inhibiting the expressions of PPARγ and FASN that related to fat synthesis.At the same time,miR-130a-3p promoted the translocation of GLUT4 from the cytoplasm to the cell membrane without affecting the expression of GLUT4 m RNA,thereby significantly increased the glucose uptake of 3T3-L1 cells.2.At the cellular level,the OE-EXO,mimics + KO-EXO(M + KO-EXO)treatment group performed the same as miR-130a-3p treatment group.While the KO-EXO,I +KO-EXO treatment group had no significant effect on 3T3-L1 cell lipid droplet formation,fat synthesis-related protein expression,carbohydrate absorption,and GLUT4 protein translocation.3.Hepatic exosomes can be absorbed and used by most organs:(1)After injection of labeled exosomes in 130 KO mice for 12 h/24 h,they can be used in heart,liver,spleen,lung,kidney,epididymal fat,fluorescence values were detected in subcutaneous fat and gastrocnemius muscle,and the fluorescence value at 24 h was significantly greater than 12 h.4.The effects of long-term injection of three exosomes on fat deposition,oxidative respiration metabolism,and glucose transport in mice:(1)Three different hepatic exosomes did not significantly change the overall fat deposition in mice,but they could significantly reduce the expression of fat synthesis-related genes in epididymal fat.(2)OE-EXO can significantly increase the oxygen consumption and heat production of130 KO mice at night.(3)Injection of OE-EXO can restore the sensitivity of glucose tolerance and insulin in 130 KO mice.At the same time,OE-EXO can promote the translocation of GLUT4 from the cytoplasm to the cell membrane,and increase the absorption of glucose by liver,gastrocnemius,and epididymal fat.5.Mi R-130a-3p affects GLUT4 translocation by inhibiting PHLPP2 and regulating the AKT-AS160-GLUT4 signal pathway:(1)There is an interaction between PHLPP2and(P-AKT/AKT)-(P-AS160/AS160)-GLUT4.(2)No matter in vitro or in vivo experiments,miR-130a-3p can inhibit the expression of PHLPP2 by targeting the 3’-UTR of PHLPP2,increase the phosphorylation of AKT and AS160,and finally promote the transfer of GLUT4 to the cell membrane.(3)Interfering RNA(si PHLPP2)of PHLPP2 can significantly increase the phosphorylation of AKT,then increase the phosphorylation of AS160,and promote the transfer of GLUT4 to the cell membrane.In summary,miR-130a-3p overexpressed hepatic exosomes can significantly inhibit lipid synthesis in 3T3-L1 cells,but significantly increase glucose transport.miR-130a-3p overexpressed hepatic exosomes can be absorbed and utilized by mouse organs,and significantly inhibit the epididymal lipid anabolic metabolism,increases the absorption of glucose by the liver and epididymal fat,as well as the overall oxidative respiratory metabolism.miR-130a-3p can reduce PHLPP2 through participating in AKT-AS160-GLUT4 signaling pathway,affecting the absorption of glucose by cells.The results have enriched people’s understanding of liver’s regulation of adipose tissue metabolism through exosomes,and provided a theoretical basis and experimental basis for exposing the application of hepatic exosomes in regulating glucose metabolism in animals and humans.