Mammals exhibit limited heart regeneration ability,which can lead to heart failure after myocardial infarction.In contrast,zebrafish exhibit remarkable cardiac regeneration capacity.Several cell types and signaling pa...Mammals exhibit limited heart regeneration ability,which can lead to heart failure after myocardial infarction.In contrast,zebrafish exhibit remarkable cardiac regeneration capacity.Several cell types and signaling pathways have been reported to participate in this process.However,a comprehensive analysis of how different cells and signals interact and coordinate to regulate cardiac regeneration is unavailable.We collected major cardiac cell types from zebrafish and performed high-precision single-cell transcriptome analyses during both development and post-injury regeneration.We revealed the cellular heterogeneity as well as the molecular progress of cardiomyocytes during these processes,and identified a subtype of atrial cardiomyocyte exhibiting a stem-like state which may transdifferentiate into ventricular cardiomyocytes during regeneration.Furthermore,we identified a regeneration-induced cell(RIC)population in the epicardium-derived cells(EPDC),and demonstrated Angiopoietin 4(Angpt4)as a specific regulator of heart regeneration.angpt4 expression is specifically and transiently activated in RIC,which initiates a signaling cascade from EPDC to endocardium through the Tie2-MAPK pathway,and further induces activation of cathepsin K in cardiomyocytes through RA signaling.Loss of angpt4 leads to defects in scar tissue resolution and cardiomyocyte proliferation,while overexpression of angpt4 accelerates regeneration.Furthermore,we found that ANGPT4 could enhance proliferation of neonatal rat cardiomyocytes,and promote cardiac repair in mice after myocardial infarction,indicating that the function of Angpt4 is conserved in mammals.Our study provides a mechanistic understanding of heart regeneration at single-cell precision,identifies Angpt4 as a key regulator of cardiomyocyte proliferation and regeneration,and offers a novel therapeutic target for improved recovery after human heart injuries.展开更多
Due to the essential role of cyclin D1 in regulating transition from G1 to S phase in cell cycle,aberrant cyclin D1 expression is a major oncogenic event in many types of cancers.In particular,the dysregulation of ubi...Due to the essential role of cyclin D1 in regulating transition from G1 to S phase in cell cycle,aberrant cyclin D1 expression is a major oncogenic event in many types of cancers.In particular,the dysregulation of ubiquitination-dependent degradation of cyclin D1 contributes to not only the pathogenesis of malignancies but also the refractory to cancer treatment regiments with CDK4/6 inhibitors.Here we show that in colorectal and gastric cancer patients,MG53 is downregulated in more than 80%of tumors compared to the normal gastrointestinal tissues from the same patient,and the reduced MG53 expression is correlated with increased cyclin D1 abundance and inferior survival.Mechanistically,MG53 catalyzes the K48-linked ubiquitination and subsequent degradation of cyclin D1.Thus,increased expression of MG53 leads to cell cycle arrest at G1,and thereby markedly suppresses cancer cell proliferation in vitro as well as tumor growth in mice with xenograft tumors or AOM/DSS induced-colorectal cancer.Consistently,MG53 deficiency results in accumulation of cyclin D1 protein and accelerates cancer cell growth both in culture and in animal models.These findings define MG53 as a tumor suppressor via facilitating cyclin D1 degradation,highlighting the therapeutic potential of targeting MG53 in treating cancers with dysregulated cyclin D1 turnover.展开更多
Dear Editor Since last year,the most demanding task of the global pharmaceutical community has been focused on the development of strategies to treat coronavirus disease 2019(COVID-19).To date,several vaccines have be...Dear Editor Since last year,the most demanding task of the global pharmaceutical community has been focused on the development of strategies to treat coronavirus disease 2019(COVID-19).To date,several vaccines have been developed and already demonstrated their efficacy in reducing the incidence of COVID-19.1 However,the development of drugs treating COVID-19 is lagging far behind,and all the current treatment regimens have their limitations.展开更多
基金the National Key Research and Development Program of China and the National Natural Science Foundation of China(NSFC)(Grant Nos.2018YFA0801001,32070824,31871458,2019YFA0802800,2016YFA0100500,31671500,81371264,31671177,and 2018YFA0800501).
文摘Mammals exhibit limited heart regeneration ability,which can lead to heart failure after myocardial infarction.In contrast,zebrafish exhibit remarkable cardiac regeneration capacity.Several cell types and signaling pathways have been reported to participate in this process.However,a comprehensive analysis of how different cells and signals interact and coordinate to regulate cardiac regeneration is unavailable.We collected major cardiac cell types from zebrafish and performed high-precision single-cell transcriptome analyses during both development and post-injury regeneration.We revealed the cellular heterogeneity as well as the molecular progress of cardiomyocytes during these processes,and identified a subtype of atrial cardiomyocyte exhibiting a stem-like state which may transdifferentiate into ventricular cardiomyocytes during regeneration.Furthermore,we identified a regeneration-induced cell(RIC)population in the epicardium-derived cells(EPDC),and demonstrated Angiopoietin 4(Angpt4)as a specific regulator of heart regeneration.angpt4 expression is specifically and transiently activated in RIC,which initiates a signaling cascade from EPDC to endocardium through the Tie2-MAPK pathway,and further induces activation of cathepsin K in cardiomyocytes through RA signaling.Loss of angpt4 leads to defects in scar tissue resolution and cardiomyocyte proliferation,while overexpression of angpt4 accelerates regeneration.Furthermore,we found that ANGPT4 could enhance proliferation of neonatal rat cardiomyocytes,and promote cardiac repair in mice after myocardial infarction,indicating that the function of Angpt4 is conserved in mammals.Our study provides a mechanistic understanding of heart regeneration at single-cell precision,identifies Angpt4 as a key regulator of cardiomyocyte proliferation and regeneration,and offers a novel therapeutic target for improved recovery after human heart injuries.
基金This project was funded by National Key R&D Program of China(2018YFA0800701,2018YFA0507603,and 2018YFA0800501)National Natural Science Foundation of China(81770376,81630008,81790621,31521062,31671177,and 81370234)+1 种基金Beijing Natural Science Foundation(5182010)Beijing Municipal Science&Technology Commission(Z171100000417006).
文摘Due to the essential role of cyclin D1 in regulating transition from G1 to S phase in cell cycle,aberrant cyclin D1 expression is a major oncogenic event in many types of cancers.In particular,the dysregulation of ubiquitination-dependent degradation of cyclin D1 contributes to not only the pathogenesis of malignancies but also the refractory to cancer treatment regiments with CDK4/6 inhibitors.Here we show that in colorectal and gastric cancer patients,MG53 is downregulated in more than 80%of tumors compared to the normal gastrointestinal tissues from the same patient,and the reduced MG53 expression is correlated with increased cyclin D1 abundance and inferior survival.Mechanistically,MG53 catalyzes the K48-linked ubiquitination and subsequent degradation of cyclin D1.Thus,increased expression of MG53 leads to cell cycle arrest at G1,and thereby markedly suppresses cancer cell proliferation in vitro as well as tumor growth in mice with xenograft tumors or AOM/DSS induced-colorectal cancer.Consistently,MG53 deficiency results in accumulation of cyclin D1 protein and accelerates cancer cell growth both in culture and in animal models.These findings define MG53 as a tumor suppressor via facilitating cyclin D1 degradation,highlighting the therapeutic potential of targeting MG53 in treating cancers with dysregulated cyclin D1 turnover.
基金This study was supported by grants from the National Key R&D Program of China(2018YFA0507600 and 2018YFA0801405)the National Natural Science Foundation of China(81970690).
文摘Dear Editor Since last year,the most demanding task of the global pharmaceutical community has been focused on the development of strategies to treat coronavirus disease 2019(COVID-19).To date,several vaccines have been developed and already demonstrated their efficacy in reducing the incidence of COVID-19.1 However,the development of drugs treating COVID-19 is lagging far behind,and all the current treatment regimens have their limitations.
