AIM:This study aims to explore the role of asprosin(ASP)in regulating hepatic lipid anabolic metabolism,as well as the effects of ASP and its downstream pathways on hepatic lipid anabolic metabolism under obesity and exercise intervention.METHODS:To explore the effect of ASP on liver lipid synthesis under physiological condi-tion,5-week-old male C57BL/6J were randomly divided into 4 groups:wild-type(WT)group,WT+ASP group,knockout(KO)group,and KO+ASP group.The mice in KO and KO+ASP groups were ASP gene heterozygous KO mice,and the re-combinant ASP protein was intraperitoneally injected into the mice in WT+ASP and KO+ASP groups for one month before sampling.To explore the role of ASP on liver lipid synthesis under obesity and exercise intervention,5-week-old male C57BL/6J mice were randomly divided into 3 groups:normal control(NC)group,high-fat diet(HFD)group,and HFD+exercise group.After 10 weeks of HFD feeding,the mice in HFD group received no intervention,while those in HFD+ex-ercise group underwent 8 weeks of treadmill exercise intervention.The mice in both groups were fed with HFD during the intervention period.After the interventions,liver tissues were collected from the mice.Western blot and RT-qPCR meth-ods were used to detect the expression levels of ASP,fibroblast growth factor 21(FGF21),nuclear factor E2-related factor 2(NRF2),stearoyl-coenzyme A desaturase 1(SCD1)and fatty acid synthase(FASN)in the mouse liver.ELISA was used to detect the triglycerol(TG)and cyclic adenosine monophosphate(cAMP)levels in the mouse liver,and HE stain-ing and oil red O staining were performed to observe the morphological changes of mouse liver tissues.RESULTS:(1)Compared with WT mice,KO mice exhibited significantly reduced body weight and liver weight,while liver index and he-patic TG levels were significantly increased.The mRNA and protein levels of cAMP,ASP,FGF21 and NRF2 in the liver were significantly decreased,whereas the mRNA and protein levels of SCD1 and FASN were significantly increased.In the WT+ASP group,liver index and hepatic TG levels were significantly reduced,but there were no statistical differences in body weight and liver weight.The mRNA and protein levels of SCD1 and FASN in the liver were significantly de-creased,while the cAMP level and the mRNA and protein levels of NRF2 were significantly increased.The FGF21 mRNA level decreased,but the protein level increased.(2)Compared with KO mice,KO+ASP mice had significantly reduced hepatic TG level,with a certain degree of reduction in liver weight and liver index,but without statistical significance.The cAMP level and the mRNA and protein levels of ASP,FGF21 and NRF2 in the liver were significantly increased,while the mRNA and protein levels of SCD1 and FASN were significantly decreased.(3)Compared with NC mice,HFD mice showed increased body weight,liver weight,and hepatic TG level.The cAMP level and the mRNA and protein levels of NRF2 in the liver were significantly decreased,while the mRNA and protein levels of SCD1 and FASN were significant-ly increased.The FGF21 mRNA level increased,but its protein level decreased.The ASP mRNA level decreased,but its protein level increased.(4)Compared with HFD mice,HFD+exercise mice had significantly reduced body weight,liver weight,and hepatic TG level.The mRNA and protein levels of SCD1 and FASN in the liver were significantly decreased,while the cAMP level and the mRNA and protein levels of NRF2 were significantly increased.The FGF21 mRNA level de-creased,but its protein level increased.The ASP mRNA level increased,but its protein level decreased.CONCLU-SION:(1)The ASP exerts an inhibitory effect on hepatic lipogenesis through the cAMP/FGF21/NRF2 pathway.(2)Un-der HFD feeding condition,the protein expression of FGF21 decreases,leading to our speculation that ASP may develop resistance.Aerobic exercise intervention can attenuate ASP resistance under high-fat condition and alleviate hepatic lipid accumulation caused by HFD.

AIM:This study aims to explore the role of asprosin(ASP)in regulating hepatic lipid anabolic metabolism,as well as the effects of ASP and its downstream pathways on hepatic lipid anabolic metabolism under obesity and exercise intervention.METHODS:To explore the effect of ASP on liver lipid synthesis under physiological condi-tion,5-week-old male C57BL/6J were randomly divided into 4 groups:wild-type(WT)group,WT+ASP group,knockout(KO)group,and KO+ASP group.The mice in KO and KO+ASP groups were ASP gene heterozygous KO mice,and the re-combinant ASP protein was intraperitoneally injected into the mice in WT+ASP and KO+ASP groups for one month before sampling.To explore the role of ASP on liver lipid synthesis under obesity and exercise intervention,5-week-old male C57BL/6J mice were randomly divided into 3 groups:normal control(NC)group,high-fat diet(HFD)group,and HFD+exercise group.After 10 weeks of HFD feeding,the mice in HFD group received no intervention,while those in HFD+ex-ercise group underwent 8 weeks of treadmill exercise intervention.The mice in both groups were fed with HFD during the intervention period.After the interventions,liver tissues were collected from the mice.Western blot and RT-qPCR meth-ods were used to detect the expression levels of ASP,fibroblast growth factor 21(FGF21),nuclear factor E2-related factor 2(NRF2),stearoyl-coenzyme A desaturase 1(SCD1)and fatty acid synthase(FASN)in the mouse liver.ELISA was used to detect the triglycerol(TG)and cyclic adenosine monophosphate(cAMP)levels in the mouse liver,and HE stain-ing and oil red O staining were performed to observe the morphological changes of mouse liver tissues.RESULTS:(1)Compared with WT mice,KO mice exhibited significantly reduced body weight and liver weight,while liver index and he-patic TG levels were significantly increased.The mRNA and protein levels of cAMP,ASP,FGF21 and NRF2 in the liver were significantly decreased,whereas the mRNA and protein levels of SCD1 and FASN were significantly increased.In the WT+ASP group,liver index and hepatic TG levels were significantly reduced,but there were no statistical differences in body weight and liver weight.The mRNA and protein levels of SCD1 and FASN in the liver were significantly de-creased,while the cAMP level and the mRNA and protein levels of NRF2 were significantly increased.The FGF21 mRNA level decreased,but the protein level increased.(2)Compared with KO mice,KO+ASP mice had significantly reduced hepatic TG level,with a certain degree of reduction in liver weight and liver index,but without statistical significance.The cAMP level and the mRNA and protein levels of ASP,FGF21 and NRF2 in the liver were significantly increased,while the mRNA and protein levels of SCD1 and FASN were significantly decreased.(3)Compared with NC mice,HFD mice showed increased body weight,liver weight,and hepatic TG level.The cAMP level and the mRNA and protein levels of NRF2 in the liver were significantly decreased,while the mRNA and protein levels of SCD1 and FASN were significant-ly increased.The FGF21 mRNA level increased,but its protein level decreased.The ASP mRNA level decreased,but its protein level increased.(4)Compared with HFD mice,HFD+exercise mice had significantly reduced body weight,liver weight,and hepatic TG level.The mRNA and protein levels of SCD1 and FASN in the liver were significantly decreased,while the cAMP level and the mRNA and protein levels of NRF2 were significantly increased.The FGF21 mRNA level de-creased,but its protein level increased.The ASP mRNA level increased,but its protein level decreased.CONCLU-SION:(1)The ASP exerts an inhibitory effect on hepatic lipogenesis through the cAMP/FGF21/NRF2 pathway.(2)Un-der HFD feeding condition,the protein expression of FGF21 decreases,leading to our speculation that ASP may develop resistance.Aerobic exercise intervention can attenuate ASP resistance under high-fat condition and alleviate hepatic lipid accumulation caused by HFD.