Rapid over-activation of β-adrenergic receptors (β-AR) following acute stress initiates cardiac inflammation and injury by activating interleukin-18 (IL-18),however,the process of inflammation cascades has not been ...Rapid over-activation of β-adrenergic receptors (β-AR) following acute stress initiates cardiac inflammation and injury by activating interleukin-18 (IL-18),however,the process of inflammation cascades has not been fully illustrated.The present study aimed to determine the mechanisms of cardiac inflammatory amplification following acute sympathetic activation.With bioinformatics analysis,galectin-3 was identified as a potential key downstream effector of β-AR and IL-18 activation.The serum level of galectin-3 was positively correlated with norepinephrine or IL-18 in patients with chest pain.In the heart of mice treated with β-AR agonist isoproterenol (ISO,5 mg kg^(-1)),galectin-3 expression was upregulated markedly later than IL-18 activation,and Nlrp3^(-/-)and Il18^(-/-)mice did not show ISO-induced galectin-3 upregulation.It was further revealed that cardiomyocyte-derived IL-18 induced galectin-3 expression in macrophages following ISO treatment.Moreover,galectin-3deficiency suppressed ISO-induced cardiac inflammation and fibrosis without blocking ISO-induced IL-18 increase.Treatment with a galectin-3 inhibitor,but not a β-blocker,one day after ISO treatment effectively attenuated cardiac inflammation and injury.In conclusion,galectin-3 is upregulated to exaggerate cardiac inflammation and injury following acute β-AR activation,a galectin-3 inhibitor effectively blocks cardiac injury one day after β-AR insult.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
Macrophage migration inhibitory factor(MIF) is an inflammatory cytokine. It is elevated early in the blood of acute myocardial infarction patients. However, it is unclear whether and how MIF is released. This study in...Macrophage migration inhibitory factor(MIF) is an inflammatory cytokine. It is elevated early in the blood of acute myocardial infarction patients. However, it is unclear whether and how MIF is released. This study investigated the cellular source and mechanism of MIF release from hearts. An ischemia-mimic treatment induced the secretion of MIF from neonatal rat cardiomyocytes but not from fibroblasts. The treatment did not cause significant leakage of lactate dehydrogenase, suggesting that ischemia induced the MIF secretion without causing severe cell damage. Plasma samples from patients with acute chest pain at the emergency department were collected for the detection of MIF. MIF levels in patients with acute coronary syndrome(ACS)increased early, when cardiac injury markers were not yet elevated, suggesting that ischemia can induce MIF secretion before the occurrence of severe myocardial damage. Serum-starvation caused MIF secretion from rat cardiomyocytes and Langendorffperfused rat hearts. The secretion was suppressed by the inhibition of autophagy by inhibitors or by silencing of Atg5. In conclusion, serum-starvation induces the secretion of MIF from cardiomyocytes via autophagy dependent pathway. Clarifying the mechanism of MIF secretion will be helpful for its application in the early diagnosis and treatment of ACS.展开更多
Stimulation of G protein-coupled receptors(GPCRs) can lead to the transactivation of the epidermal growth factor receptors(EGFR). The cross-communication between the two signaling pathways regulates several important ...Stimulation of G protein-coupled receptors(GPCRs) can lead to the transactivation of the epidermal growth factor receptors(EGFR). The cross-communication between the two signaling pathways regulates several important physiological or pathological processes. However, the molecule mechanism underlying EGFR transactivation remains poorly understood. Here, we aim to study the GPCR-mediated EGFR transactivation process using the single-molecule fluorescence imaging and tracking approach.We found that although EGFR existed as monomers at the plasma membrane of resting cells, they became dimers and thus diffused slower following the activation of β2-adrenergic receptor(β2-AR) by isoproterenol(ISO). We further proved thatβ2-AR-mediated changes of EGFR in stoichiometry and dynamics were mediated by Src kinase. Thus, the observations obtained via the single-molecule imaging and tracking methods shed new insights into the molecular mechanism of EGFR transactivation at single molecule level.展开更多
基金supported by the National Key R&D Program of China (2021YFF0501401)the National Natural Science Foundation of China (82030072)+5 种基金the Michigan Medicine-PKUHSC Joint Institute for Translational and Clinical Research (BMU2019JI007)the Fundamental Research Funds for the Central Universitiesthe National Natural Science Foundation of China (81830009, 81822003)the Beijing Municipal Natural Science Foundation (7191013)the Key Clinical Projects of Peking University Third Hospital (BYSYZD2019022)CAMS Innovation Fund for Medical Sciences to (2021-I2M-5-003)。
文摘Rapid over-activation of β-adrenergic receptors (β-AR) following acute stress initiates cardiac inflammation and injury by activating interleukin-18 (IL-18),however,the process of inflammation cascades has not been fully illustrated.The present study aimed to determine the mechanisms of cardiac inflammatory amplification following acute sympathetic activation.With bioinformatics analysis,galectin-3 was identified as a potential key downstream effector of β-AR and IL-18 activation.The serum level of galectin-3 was positively correlated with norepinephrine or IL-18 in patients with chest pain.In the heart of mice treated with β-AR agonist isoproterenol (ISO,5 mg kg^(-1)),galectin-3 expression was upregulated markedly later than IL-18 activation,and Nlrp3^(-/-)and Il18^(-/-)mice did not show ISO-induced galectin-3 upregulation.It was further revealed that cardiomyocyte-derived IL-18 induced galectin-3 expression in macrophages following ISO treatment.Moreover,galectin-3deficiency suppressed ISO-induced cardiac inflammation and fibrosis without blocking ISO-induced IL-18 increase.Treatment with a galectin-3 inhibitor,but not a β-blocker,one day after ISO treatment effectively attenuated cardiac inflammation and injury.In conclusion,galectin-3 is upregulated to exaggerate cardiac inflammation and injury following acute β-AR activation,a galectin-3 inhibitor effectively blocks cardiac injury one day after β-AR insult.
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.
基金supported by the Beijing Municipal Natural Science Foundation (7144254)the National Nature Science Foundation of China (81530009, 81670205)+1 种基金the Open Foundation from Beijing Key Laboratory of Hypertension Research (2017GXY-KFKT-05)the Fund for Fostering Young Scholars of Peking University Health Science Center (BMU2017PY016)
文摘Macrophage migration inhibitory factor(MIF) is an inflammatory cytokine. It is elevated early in the blood of acute myocardial infarction patients. However, it is unclear whether and how MIF is released. This study investigated the cellular source and mechanism of MIF release from hearts. An ischemia-mimic treatment induced the secretion of MIF from neonatal rat cardiomyocytes but not from fibroblasts. The treatment did not cause significant leakage of lactate dehydrogenase, suggesting that ischemia induced the MIF secretion without causing severe cell damage. Plasma samples from patients with acute chest pain at the emergency department were collected for the detection of MIF. MIF levels in patients with acute coronary syndrome(ACS)increased early, when cardiac injury markers were not yet elevated, suggesting that ischemia can induce MIF secretion before the occurrence of severe myocardial damage. Serum-starvation caused MIF secretion from rat cardiomyocytes and Langendorffperfused rat hearts. The secretion was suppressed by the inhibition of autophagy by inhibitors or by silencing of Atg5. In conclusion, serum-starvation induces the secretion of MIF from cardiomyocytes via autophagy dependent pathway. Clarifying the mechanism of MIF secretion will be helpful for its application in the early diagnosis and treatment of ACS.
基金supported by the National Basic Research Program of China (2013CB933701)the National Natural Science Foundation of China (81530009, 21127901, 91213305)Chinese Academy of Science
文摘Stimulation of G protein-coupled receptors(GPCRs) can lead to the transactivation of the epidermal growth factor receptors(EGFR). The cross-communication between the two signaling pathways regulates several important physiological or pathological processes. However, the molecule mechanism underlying EGFR transactivation remains poorly understood. Here, we aim to study the GPCR-mediated EGFR transactivation process using the single-molecule fluorescence imaging and tracking approach.We found that although EGFR existed as monomers at the plasma membrane of resting cells, they became dimers and thus diffused slower following the activation of β2-adrenergic receptor(β2-AR) by isoproterenol(ISO). We further proved thatβ2-AR-mediated changes of EGFR in stoichiometry and dynamics were mediated by Src kinase. Thus, the observations obtained via the single-molecule imaging and tracking methods shed new insights into the molecular mechanism of EGFR transactivation at single molecule level.
