Background:Promoting cardiac lymphangiogenesis exerts beneficial effects for the heart.Exercise can induce physiological cardiac growth with cardiomyocyte hypertrophy and increased proliferation markers in cardiomyocytes.However,it remains unclear whether and how lymphangio-genesis contributes to exercise-induced physiological cardiac growth.We aimed to investigate the role and mechanism of lymphangiogenesis in exercise-induced physiological cardiac growth.Methods:Adult C57BL6/J mice were subjected to 3 weeks of swimming exercise to induce physiological cardiac growth.Oral treatment with vascular endothelial growth factor receptor 3(VEGFR3)inhibitor SAR1 31675 was used to investigate whether cardiac lymphangiogenesis was required for exercise-induced physiological cardiac growth by VEGFR3 activation.Furthermore,human dermal lymphatic endothelial cell(LEC)-conditioned medium was collected to culture isolated neonatal rat cardiomyocytes to determine whether and how LECs could influence cardiomyocyte proliferation and hypertrophy.Results:Swimming exercise induced physiological cardiac growth accompanied by a remarkable increase of cardiac lymphangiogenesis as evi-denced by increased density of lymphatic vessel endothelial hyaluronic acid receptor l-positive lymphatic vessels in the heart and upregulated LYVE-1 and Podoplanin expressions levels.VEGFR3 was upregulated in the exercised heart,while VEGFR3 inhibitor SAR1 31675 attenuated exercise-induced physiological cardiac growth as evidenced by blunted myocardial hypertrophy and reduced proliferation marker Ki67 in cardio-myocytes,which was correlated with reduced lymphatic vessel density and downregulated LYVE-1 and Podoplanin in the heart upon exercise.Furthermore,LEC-conditioned medium promoted both hypertrophy and proliferation of cardiomyocytes and contained higher levels of insulin-like growth factor-1 and the extracellular protein Reelin,while LEC-conditioned medium from LECs treated with SAR131675 blocked these effects.Functional rescue assays further demonstrated that protein kinase B(AKT)activation,as well as reduced CCAAT enhancer-binding pro-tein beta(C/EBPβ)and increased CBP/p300-interacting transactivators with E(glutamic acid)/D(aspartic acid)-rich-carboxylterminal domain 4(CITED4),contributed to the promotive effect of LEC-conditioned medium on cardiomyocyte hypertrophy and proliferation.Conclusion:Our findings reveal that cardiac lymphangiogenesis is required for exercise-induced physiological cardiac growth by VEGFR3 acti-vation,and they indicate that LEC-conditioned medium promotes both physiological hypertrophy and proliferation of cardiomyocytes through AKT activation and the C/EBPβ-CITED4 axis.These results highlight the essential roles of cardiac lymphangiogenesis in exercise-induced physiological cardiac growth.

Yihua Bei;Zhenzhen Huang;Xing Feng;Lin Li;Meng Wei;Yujiao Zhu;Shuqin Liu;Chen Chen;Mingming Yin;Huimin Jiang;Junjie Xiao

Cardiac Regeneration and Ageing Lab,Institute of Geriatrics(Shanghai University),Affiliated Nantong Hospital of Shanghai University(The Sixth People's Hospital of Nantong),School of Medicine,Shanghai University,Nantong 226011,China;Shanghai Engineering Research Center of Organ Repair,School of Life Science,Shanghai University,Shanghai 200444,China;Clinical Laboratory Center,Beijing Hospital of Traditional Chinese Medicine,Beijing 100010,China

运动与健康科学（英文）

[1]Yihua Bei;Zhenzhen Huang;Xing Feng;Lin Li;Meng Wei;Yujiao Zhu;Shuqin Liu;Chen Chen;Mingming Yin;Huimin Jiang;Junjie Xiao-.Lymphangiogenesis contributes to exercise-induced physiological cardiac growth)[J].运动与健康科学（英文）,2022(04):466-478

Lymphangiogenesis,lymphangiogenesis,lymphangio,SAR1,Reelin,transactivators,carboxylterminal,CITED4

contributes,induced,physiological,cardiac,growth,Background,Promoting,exerts,beneficial,effects,heart,Exercise,can,hypertrophy,increased,proliferation,markers,cardiomyocytes,However,remains,unclear,whether,how,We,aimed,investigate,mechanism,Methods,Adult,C57BL6,mice,were,subjected,weeks,swimming,Oral,treatment,vascular,endothelial,receptor,VEGFR3,inhibitor,was,used,required,by,activation,Furthermore,human,dermal,lymphatic,conditioned,medium,collected,culture,isolated,neonatal,determine,LECs,could,influence,Results,Swimming,accompanied,remarkable,density,hyaluronic,acid,positive,vessels,upregulated,LYVE,Podoplanin,expressions,levels,exercised,while,attenuated,evidenced,blunted,myocardial,reduced,Ki67,which,correlated,downregulated,upon,promoted,both,contained,higher,insulin,like,extracellular,protein,from,treated,SAR131675,blocked,these,Functional,rescue,assays,further,demonstrated,that,kinase,AKT,well,CCAAT,enhancer,binding,beta,EBP,CBP,p300,interacting,glutamic,aspartic,rich,domain,contributed,promotive,Conclusion,Our,findings,reveal,they,indicate,promotes,through,axis,These,results,highlight,essential,roles

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