Background:Exercise training protects against heart failure.However,the mechanism underlying the protective effect of exercise training on angiotensinⅡ(AngⅡ)-induced cardiac fibrosis remains unclear.Methods:An exerc...Background:Exercise training protects against heart failure.However,the mechanism underlying the protective effect of exercise training on angiotensinⅡ(AngⅡ)-induced cardiac fibrosis remains unclear.Methods:An exercise model involving C57BL/6N mice and 6 weeks of treadmill training was used.AngⅡ(1.44 mg/kg/day)was administered to induce cardiac fibrosis.RNA sequencing and bioinformatic analysis were used to identify the key factors mediating the effects of exercise training on cardiac fibrosis.Primary adult mouse cardiac fibroblasts(CFs)were used in vitro.Adeno-associated virus serotype 9 was used to overexpress POU domain,class 2,transcription factor 1(POU2F1)in vivo.Results:Exercise training attenuated AngⅡ-induced cardiac fibrosis and reversed 39 gene expression changes.The transcription factor regulating the largest number of these genes was POU2F1.Compared to controls,POU2F1 was shown to be signififcantly upregulated by AngⅡ,which is itself reduced by exercise training.In vivo,POU2F1 overexpression nullified the benefits of exercise training on cardiac fibrosis.In CFs,POU2F1 promoted cardiac fibrosis.CCAAT enhancer-binding proteinβ(C/EBPβ)was predicted to be the transcription factor of POU2F1and verified using a dual-luciferase reporter assay.In vivo,exercise training activated AMP-activated protein kinase(AMPK)and alleviated the increase in C/EBPβinduced by AngⅡ.In CFs,AMPK agonist inhibited the increase in C/EBPβand POU2F1 induced by Ang II,whereas AMPK inhibitor reversed this effect.Conclusion:Exercise training attenuates AngⅡ-induced cardiac fibrosis by reducing POU2F1.Exercise training inhibits POU2F1 by activating AMPK,which is followed by the downregulation of C/EBPβ,the transcription factor of POU2F1.展开更多
Cardiac fibroblast(CF)differentiation into myofibroblasts is a crucial cause of cardiac fibrosis,which increases in the extracellular matrix(ECM)stiffness.The increased stiffness further promotes CF differentiation an...Cardiac fibroblast(CF)differentiation into myofibroblasts is a crucial cause of cardiac fibrosis,which increases in the extracellular matrix(ECM)stiffness.The increased stiffness further promotes CF differentiation and fibrosis.However,the molecular mechanism is still unclear.We used bioinformatics analysis to find new candidates that regulate the genes involved in stiffnessinduced CF differentiation,and found that there were binding sites for the POU-domain transcription factor,POU2F1(also known as Oct-1),in the promoters of 50 differentially expressed genes(DEGs)in CFs on the stiffer substrate.Immunofluorescent staining and Western blotting revealed that pathological stiffness upregulated POU2F1 expression and increased CF differentiation on polyacrylamide hydrogel substrates and in mouse myocardial infarction tissue.A chromatin immunoprecipitation assay showed that POU2F1 bound to the promoters of fibrosis repressors IL1R2,CD69,and TGIF2.The expression of these fibrosis repressors was inhibited on pathological substrate stiffness.Knockdown of POU2F1 upregulated these repressors and attenuated CF differentiation on pathological substrate stiffness(35 kPa).Whereas,overexpression of POU2F1 downregulated these repressors and enhanced CF differentiation.In conclusion,pathological stiffness upregulates the transcription factor POU2F1 to promote CF differentiation by inhibiting fibrosis repressors.Our work elucidated the crosstalk between CF differentiation and the ECM and provided a potential target for cardiac fibrosis treatment.展开更多
基金supported by the National Natural Science Foundation of China(82030072 to HX,81871850 to HY,81972149 to WG,and 81830009 to YZ)Beijing Natural Science Foundation(No.7212125 to HY)+2 种基金National Key R&D Program of China(Grant No.2020YFA0803800 to HY)the Key Clinical Projects of Peking University Third Hospital(BYSYZD2019022 to HX)Chinese Academy of Medical Sciences(CAMS)Innovation Fund for Medical Sciences(No.2021-I2M-5-003 to HX and YZ)。
文摘Background:Exercise training protects against heart failure.However,the mechanism underlying the protective effect of exercise training on angiotensinⅡ(AngⅡ)-induced cardiac fibrosis remains unclear.Methods:An exercise model involving C57BL/6N mice and 6 weeks of treadmill training was used.AngⅡ(1.44 mg/kg/day)was administered to induce cardiac fibrosis.RNA sequencing and bioinformatic analysis were used to identify the key factors mediating the effects of exercise training on cardiac fibrosis.Primary adult mouse cardiac fibroblasts(CFs)were used in vitro.Adeno-associated virus serotype 9 was used to overexpress POU domain,class 2,transcription factor 1(POU2F1)in vivo.Results:Exercise training attenuated AngⅡ-induced cardiac fibrosis and reversed 39 gene expression changes.The transcription factor regulating the largest number of these genes was POU2F1.Compared to controls,POU2F1 was shown to be signififcantly upregulated by AngⅡ,which is itself reduced by exercise training.In vivo,POU2F1 overexpression nullified the benefits of exercise training on cardiac fibrosis.In CFs,POU2F1 promoted cardiac fibrosis.CCAAT enhancer-binding proteinβ(C/EBPβ)was predicted to be the transcription factor of POU2F1and verified using a dual-luciferase reporter assay.In vivo,exercise training activated AMP-activated protein kinase(AMPK)and alleviated the increase in C/EBPβinduced by AngⅡ.In CFs,AMPK agonist inhibited the increase in C/EBPβand POU2F1 induced by Ang II,whereas AMPK inhibitor reversed this effect.Conclusion:Exercise training attenuates AngⅡ-induced cardiac fibrosis by reducing POU2F1.Exercise training inhibits POU2F1 by activating AMPK,which is followed by the downregulation of C/EBPβ,the transcription factor of POU2F1.
基金support of a grant from the National Natural Science Foundation of China(81530009 to Y.Y.Z.)a grant from the National Natural Science Foundation of China(81822003 and 81670205 to H.X.)a grant from Natural Science Foundation of Beijing Municipality(7191013 to E.D.D.).
文摘Cardiac fibroblast(CF)differentiation into myofibroblasts is a crucial cause of cardiac fibrosis,which increases in the extracellular matrix(ECM)stiffness.The increased stiffness further promotes CF differentiation and fibrosis.However,the molecular mechanism is still unclear.We used bioinformatics analysis to find new candidates that regulate the genes involved in stiffnessinduced CF differentiation,and found that there were binding sites for the POU-domain transcription factor,POU2F1(also known as Oct-1),in the promoters of 50 differentially expressed genes(DEGs)in CFs on the stiffer substrate.Immunofluorescent staining and Western blotting revealed that pathological stiffness upregulated POU2F1 expression and increased CF differentiation on polyacrylamide hydrogel substrates and in mouse myocardial infarction tissue.A chromatin immunoprecipitation assay showed that POU2F1 bound to the promoters of fibrosis repressors IL1R2,CD69,and TGIF2.The expression of these fibrosis repressors was inhibited on pathological substrate stiffness.Knockdown of POU2F1 upregulated these repressors and attenuated CF differentiation on pathological substrate stiffness(35 kPa).Whereas,overexpression of POU2F1 downregulated these repressors and enhanced CF differentiation.In conclusion,pathological stiffness upregulates the transcription factor POU2F1 to promote CF differentiation by inhibiting fibrosis repressors.Our work elucidated the crosstalk between CF differentiation and the ECM and provided a potential target for cardiac fibrosis treatment.
