Objective:To explore the effects of high-intensity interval training(HIIT)and semaglutide on cardiomyopathy and glycophagy in db/db mice.Method:Forty male db/db mice were randomly divided into diabetic control group(DC,n=10),diabetic+exercise group(DE,n=10),diabetic+semaglutide group(DM,n=10)and diabetic+exercise+semaglutide group(EM,n=10).DE mice and EM mice were conducted a 8-week HIIT treadmill protocol,DM mice and EM mice received daily subcutaneous neck injections of semaglutide at 0.05mg/kg.Body weight and fasting blood glucose were measured regularly.Echocardiography was used to detect cardiac function at the end of the intervention.Myocardial morphology was evaluated by H&E staining;The H&E staining was used to observe the myocardial morphological changes;fibrosis by Masson staining;glycogen accumulation by periodic acid-Schiff staining;and cardiomyocyte hypertrophy by wheat germ agglutinin(WGA)staining.The glycophagy was observed by transmission electron microscopy.Western Blot quantified the IRS-1,P-PI3K,PI3K,p-AKT,AKT,p-GSK3β,GSK3β,p-AMPK,AMPK,p-mTOR,mTOR,LC3Ⅱ/Ⅰ,TFEB and GABARAPL1 in myocar-dial tissue.Result:Compared with DC group,HIIT and/or semaglutide intervention reduced body weight and fasting glu-cose,improved cardiac function and myocardial morphology,decreased fibrosis and cardiomyocyte hypertrophy(reduced cross-sectional area,P<0.05),and lowered glycogen accumulation.Autophagosomes and autophagy vac-uoles containing different amounts of glycogen granule were observed by transmission electron microscopy.Compared with DC group,the protein level of p-mTOR/mTOR in DE mice was significantly decreased,and the protein levels of LC3Ⅱ/Ⅰ,TFEB and GABARAPL1 in DE mice were significantly increased(P<0.05).The phosphorylation levels of AKT and GSK3β in DM mice was significantly increased,and the protein level of TFEB and GABARAPL1 in DM mice was significantly increased(P<0.05).The protein levels of IRS-1,LC3Ⅱ/Ⅰ,TFEB and GABAPARAL1 in EM mice significantly increased,the phosphorylation levels of PI3K,AKT,GSK3β and AMPK were significantly increased.The p-mTOR/mTOR ratio of autophagy negative regula-tor in EM mice was decreased(P<0.05).Compared with single treatment group,the AMPK phosphorylation and LC3Ⅱ/Ⅰ protein expression in EM group were significantly increased(P<0.05).Conclusion:HIIT and semaglutide can improve myocardial fibrosis,glycogen accumulation and cardiac func-tion in db/db mice,and the combined intervention group yields the most pronounced effects,which may be re-lated to AMPK/mTOR pathway activation,enhanced cardiac glycophagy,and reduced myocardial injury.

Objective:To explore the effects of high-intensity interval training(HIIT)and semaglutide on cardiomyopathy and glycophagy in db/db mice.Method:Forty male db/db mice were randomly divided into diabetic control group(DC,n=10),diabetic+exercise group(DE,n=10),diabetic+semaglutide group(DM,n=10)and diabetic+exercise+semaglutide group(EM,n=10).DE mice and EM mice were conducted a 8-week HIIT treadmill protocol,DM mice and EM mice received daily subcutaneous neck injections of semaglutide at 0.05mg/kg.Body weight and fasting blood glucose were measured regularly.Echocardiography was used to detect cardiac function at the end of the intervention.Myocardial morphology was evaluated by H&E staining;The H&E staining was used to observe the myocardial morphological changes;fibrosis by Masson staining;glycogen accumulation by periodic acid-Schiff staining;and cardiomyocyte hypertrophy by wheat germ agglutinin(WGA)staining.The glycophagy was observed by transmission electron microscopy.Western Blot quantified the IRS-1,P-PI3K,PI3K,p-AKT,AKT,p-GSK3β,GSK3β,p-AMPK,AMPK,p-mTOR,mTOR,LC3Ⅱ/Ⅰ,TFEB and GABARAPL1 in myocar-dial tissue.Result:Compared with DC group,HIIT and/or semaglutide intervention reduced body weight and fasting glu-cose,improved cardiac function and myocardial morphology,decreased fibrosis and cardiomyocyte hypertrophy(reduced cross-sectional area,P<0.05),and lowered glycogen accumulation.Autophagosomes and autophagy vac-uoles containing different amounts of glycogen granule were observed by transmission electron microscopy.Compared with DC group,the protein level of p-mTOR/mTOR in DE mice was significantly decreased,and the protein levels of LC3Ⅱ/Ⅰ,TFEB and GABARAPL1 in DE mice were significantly increased(P<0.05).The phosphorylation levels of AKT and GSK3β in DM mice was significantly increased,and the protein level of TFEB and GABARAPL1 in DM mice was significantly increased(P<0.05).The protein levels of IRS-1,LC3Ⅱ/Ⅰ,TFEB and GABAPARAL1 in EM mice significantly increased,the phosphorylation levels of PI3K,AKT,GSK3β and AMPK were significantly increased.The p-mTOR/mTOR ratio of autophagy negative regula-tor in EM mice was decreased(P<0.05).Compared with single treatment group,the AMPK phosphorylation and LC3Ⅱ/Ⅰ protein expression in EM group were significantly increased(P<0.05).Conclusion:HIIT and semaglutide can improve myocardial fibrosis,glycogen accumulation and cardiac func-tion in db/db mice,and the combined intervention group yields the most pronounced effects,which may be re-lated to AMPK/mTOR pathway activation,enhanced cardiac glycophagy,and reduced myocardial injury.

New threats posed by the emerging circulating variants of SARS-CoV-2 highlight the need to find conserved neutralizing epitopes for therapeutic antibodies and efficient vaccine design. Here, we identified a receptor-binding domain (RBD)-binding antibody, XG014, which potently neutralizes β-coronavirus lineage B (β-CoV-B), including SARS-CoV-2, its circulating variants, SARS-CoV and bat SARSr-CoV WIV1. Interestingly, antibody family members competing with XG014 binding show reduced levels of cross-reactivity and induce antibody-dependent SARS-CoV-2 spike (S) protein-mediated cell-cell fusion, suggesting a unique mode of recognition by XG014. Structural analyses reveal that XG014 recognizes a conserved epitope outside the ACE2 binding site and completely locks RBD in the non-functional "down" conformation, while its family member XG005 directly competes with ACE2 binding and position the RBD "up". Single administration of XG014 is effective in protection against and therapy of SARS-CoV-2 infection in vivo. Our findings suggest the potential to develop XG014 as pan-β-CoV-B therapeutics and the importance of the XG014 conserved antigenic epitope for designing broadly protective vaccines against β-CoV-B and newly emerging SARS-CoV-2 variants of concern.
Angiotensin-Converting Enzyme 2 ; Antibodies, Neutralizing ; Antibodies, Viral ; COVID-19 ; Epitopes ; Humans ; SARS-CoV-2/genetics* ; Spike Glycoprotein, Coronavirus/genetics*