Background—Dicer, an RNAse III endonuclease critical for processing of pre-microRNAs (miRNAs) int... more Background—Dicer, an RNAse III endonuclease critical for processing of pre-microRNAs (miRNAs) into mature 22-nucleotide miRNAs, has proven a useful target to dissect the significance of miRNAs biogenesis in mammalian biology. Methods and Results—To circumvent the embryonic lethality associated with germline null mutations for Dicer, we triggered conditional Dicer loss through the use of a tamoxifen-inducible Cre recombinase in the postnatal murine myocardium. Targeted Dicer deletion in 3-week-old mice provoked premature death within 1 week accompanied by mild ventricular remodeling and dramatic atrial enlargement. In the adult myocardium, loss of Dicer induced rapid and dramatic biventricular enlargement, accompanied by myocyte hypertrophy, myofiber disarray, ventricular fibrosis, and strong induction of fetal gene transcripts. Comparative miRNA profiling revealed a set of miRNAs that imply causality between miRNA depletion and spontaneous cardiac remodeling. Conclusions—Overall, th...
This editorial refers to ‘The heart requires glycerol as an energy substrate through aquaporin 7,... more This editorial refers to ‘The heart requires glycerol as an energy substrate through aquaporin 7, a glycerol facilitator ’ by T. Hibuse et al.,15 pp. 34–41, this issue. Deprivation of available energy has been postulated to play a major role in the genesis of heart failure,1–3 and accumulating evidence points to the premise that changes in gene expression that alter energy metabolism weaken the heart muscle,4,5 reinforcing the logic of ameliorating energy sub-strates, and/or metabolism as a heart failure therapeutic. Reduced cardiac energy levels, in turn, influence a plethora of cardiac events, including free radical defense mechanisms which lower cardiomyocyte survivability,6 cardiac contracti-lity,7 adverse remodelling and arrhythmogenic susceptibility.8 The heart is able to produce energy from a wide range of substrates and shifts continuously between sources, accord-
Information about reprints can be found online at: Reprints: document. Permissions and Rights Que... more Information about reprints can be found online at: Reprints: document. Permissions and Rights Question and Answer this process is available in the click Request Permissions in the middle column of the Web page under Services. Further information about Office. Once the online version of the published article for which permission is being requested is located, can be obtained via RightsLink, a service of the Copyright Clearance Center, not the EditorialCirculationin Requests for permissions to reproduce figures, tables, or portions of articles originally publishedPermissions: by guest on February 28,
MicroRNAs (miRs) are a class of single-stranded, non-coding RNAs of ∼22 nucleotides in length, an... more MicroRNAs (miRs) are a class of single-stranded, non-coding RNAs of ∼22 nucleotides in length, and growing evidence indicates that miRs are implicated in myocardial disease processes. A key pathway involved in heart failure consists of the phosphatase calcineurin and its downstream transcription factor Nuclear Factor of Activated T-cells (NFAT). We performed microRNA profiling in hearts from calcineurin transgenic mice and demonstrated that microRNA-199b (miR-199b) is a direct calcineurin/NFAT target gene. MiR-199b increases in expression in mouse and human heart failure, and targets the nuclear NFAT kinase dual-specificity tyrosine-(Y)-phosphorylation regulated kinase 1a (Dyrk1a), constituting a pathogenic feed forward mechanism with impact on calcineurin-responsive gene expression. Interestingly, cardiac miR-199b levels inversely correlated with cardiac Dyrk1a expression in biopsies of failing human hearts secondary to ischemic heart disease or non-ischemic dilated cardiomyopathy....
Highlight: In this Onlife interview, Professor Pasterkamp talks about current challenges in the a... more Highlight: In this Onlife interview, Professor Pasterkamp talks about current challenges in the atherosclerotic field and the best ways to translate basic science into clinical practice.
The efficiency of the repair process following ischemic cardiac injury is a crucial determinant f... more The efficiency of the repair process following ischemic cardiac injury is a crucial determinant for the progression into heart failure and is controlled by both intra- and intercellular signaling within the heart. An enhanced understanding of this complex interplay will enable better exploitation of these mechanisms for therapeutic use. We used single-cell transcriptomics to collect gene expression data of all main cardiac cell types at different time-points after ischemic injury. These data unveiled cellular and transcriptional heterogeneity and changes in cellular function during cardiac remodeling. Furthermore, we established potential intercellular communication networks after ischemic injury. Follow up experiments confirmed that cardiomyocytes express and secrete elevated levels of beta-2 microglobulin in response to ischemic damage, which can activate fibroblasts in a paracrine manner. Collectively, our data indicate phase-specific changes in cellular heterogeneity during diff...
After the publication of the original article, we noticed that we need a correction in Fig. 2. In... more After the publication of the original article, we noticed that we need a correction in Fig. 2. In the part of the table containing human studies, in Nomura et al. (2018), in the column indicating the type of samples, sham and TAC was now correctly replaced with healthy and DCM. Please see below the corrected version. We apologize for any inconvenience that this may have caused. Publisher's Note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
Purpose of the Review Cardiovascular disease remains the leading cause of death worldwide, result... more Purpose of the Review Cardiovascular disease remains the leading cause of death worldwide, resulting in cardiac dysfunction and, subsequently, heart failure (HF). Single-cell RNA sequencing (scRNA-seq) is a rapidly developing tool for studying the transcriptional heterogeneity in both healthy and diseased hearts. Wide applications of techniques like scRNA-seq could significantly contribute to uncovering the molecular mechanisms involved in the onset and progression to HF and contribute to the development of new, improved therapies. This review discusses several studies that successfully applied scRNA-seq to the mouse and human heart using various methods of tissue processing and downstream analysis. Recent Findings The application of scRNA-seq in the cardiovascular field is continuously expanding, providing new detailed insights into cardiac pathophysiology. Summary Increased understanding of cardiac pathophysiology on the single-cell level will contribute to the development of nove...
Aims Pathological cardiac remodelling is characterized by cardiomyocyte (CM) hypertrophy and fibr... more Aims Pathological cardiac remodelling is characterized by cardiomyocyte (CM) hypertrophy and fibroblast activation, which can ultimately lead to maladaptive hypertrophy and heart failure (HF). Genome-wide expression analysis on heart tissue has been instrumental for the identification of molecular mechanisms at play. However, these data were based on signals derived from all cardiac cell types. Here, we aimed for a more detailed view on molecular changes driving maladaptive CM hypertrophy to aid in the development of therapies to reverse pathological remodelling. Methods and results Utilizing CM-specific reporter mice exposed to pressure overload by transverse aortic banding and CM isolation by flow cytometry, we obtained gene expression profiles of hypertrophic CMs in the more immediate phase after stress, and CMs showing pathological hypertrophy. We identified subsets of genes differentially regulated and specific for either stage. Among the genes specifically up-regulated in the ...
The disruption in blood supply due to myocardial infarction is a critical determinant for infarct... more The disruption in blood supply due to myocardial infarction is a critical determinant for infarct size and subsequent deterioration in function. The identification of factors that enhance cardiac repair by the restoration of the vascular network is, therefore, of great significance. Here, we show that the transcription factor Zinc finger E-box-binding homeobox 2 (ZEB2) is increased in stressed cardiomyocytes and induces a cardioprotective cross-talk between cardiomyocytes and endothelial cells to enhance angiogenesis after ischemia. Single-cell sequencing indicates ZEB2 to be enriched in injured cardiomyocytes. Cardiomyocyte-specific deletion of ZEB2 results in impaired cardiac contractility and infarct healing post-myocardial infarction (post-MI), while cardiomyocyte-specific ZEB2 overexpression improves cardiomyocyte survival and cardiac function. We identified Thymosin β4 (TMSB4) and Prothymosin α (PTMA) as main paracrine factors released from cardiomyocytes to stimulate angiogen...
during the first 24 hours after returning to thermo-neutral conditions. The autophagic flux, dete... more during the first 24 hours after returning to thermo-neutral conditions. The autophagic flux, determined by assessment of LC3b II after leupeptin treatment in vivo, was repressed during cold exposure and strongly reactivated after 24 hours of thermoneutrality. We further confirmed these results using electron microscopy and we found increased abundance of autophagosomes after acute deacclimation. Conclusions: Our data indicates that mice exposed to three weeks of cold develop a marked cardiac hypertrophy, reversed after one week of deacclimation. We propose autophagy as one of the mechanisms leading to heart remodeling in response to cold exposure and its posterior reversion after deacclimation.
Introduction: Diabetes is an independent risk factor for cardiovascular disease, with 50% of diab... more Introduction: Diabetes is an independent risk factor for cardiovascular disease, with 50% of diabetic patients developing cardiomyopathy, including fibrosis. Substance P (SP) is a neuropeptide located in sensory nerves, and diabetic rat hearts have reduced levels of SP. This reduced SP appears to contribute to the loss of cardioprotection in response to ischaemic post conditioning, indicating that SP may play a protective role in diabetic hearts. Purpose: Our aim was to further examine the cardio-protective role of SP in diabetes. We hypothesised that a loss of SP leads to fibrosis in diabetic hearts and that this adverse remodelling is reversible by restoring SP levels. Methods: 10 week old Leprdb obese diabetic mice received a daily subcutaneous injection of either saline or SP (1mg/kg) for four weeks. Wild type C57B/6 mice were included as controls. For in vitro studies, cardiac fibroblasts were isolated and treated with SP (10, 30, 100, 300 and 1000 nM) in high glucose media (DMEM þ 9 g/L of glucose) for 24 hours to mimic diabetes. SP levels were also measured in plasma samples from diabetic patients. Abstract 238 Figure. Collagen Volume Fraction Results: Our results showed that cardiac fibrosis is significantly increased in the Leprdb mouse compared to the wild type group (Figure). This increase in fibrosis was reduced by SP replacement, independent of blood pressure, body weight and blood glucose levels. SP is known to resolve uncontrolled inflammation in diabetic wound healing, however, it did not alter the
Background—Dicer, an RNAse III endonuclease critical for processing of pre-microRNAs (miRNAs) int... more Background—Dicer, an RNAse III endonuclease critical for processing of pre-microRNAs (miRNAs) into mature 22-nucleotide miRNAs, has proven a useful target to dissect the significance of miRNAs biogenesis in mammalian biology. Methods and Results—To circumvent the embryonic lethality associated with germline null mutations for Dicer, we triggered conditional Dicer loss through the use of a tamoxifen-inducible Cre recombinase in the postnatal murine myocardium. Targeted Dicer deletion in 3-week-old mice provoked premature death within 1 week accompanied by mild ventricular remodeling and dramatic atrial enlargement. In the adult myocardium, loss of Dicer induced rapid and dramatic biventricular enlargement, accompanied by myocyte hypertrophy, myofiber disarray, ventricular fibrosis, and strong induction of fetal gene transcripts. Comparative miRNA profiling revealed a set of miRNAs that imply causality between miRNA depletion and spontaneous cardiac remodeling. Conclusions—Overall, th...
This editorial refers to ‘The heart requires glycerol as an energy substrate through aquaporin 7,... more This editorial refers to ‘The heart requires glycerol as an energy substrate through aquaporin 7, a glycerol facilitator ’ by T. Hibuse et al.,15 pp. 34–41, this issue. Deprivation of available energy has been postulated to play a major role in the genesis of heart failure,1–3 and accumulating evidence points to the premise that changes in gene expression that alter energy metabolism weaken the heart muscle,4,5 reinforcing the logic of ameliorating energy sub-strates, and/or metabolism as a heart failure therapeutic. Reduced cardiac energy levels, in turn, influence a plethora of cardiac events, including free radical defense mechanisms which lower cardiomyocyte survivability,6 cardiac contracti-lity,7 adverse remodelling and arrhythmogenic susceptibility.8 The heart is able to produce energy from a wide range of substrates and shifts continuously between sources, accord-
Information about reprints can be found online at: Reprints: document. Permissions and Rights Que... more Information about reprints can be found online at: Reprints: document. Permissions and Rights Question and Answer this process is available in the click Request Permissions in the middle column of the Web page under Services. Further information about Office. Once the online version of the published article for which permission is being requested is located, can be obtained via RightsLink, a service of the Copyright Clearance Center, not the EditorialCirculationin Requests for permissions to reproduce figures, tables, or portions of articles originally publishedPermissions: by guest on February 28,
MicroRNAs (miRs) are a class of single-stranded, non-coding RNAs of ∼22 nucleotides in length, an... more MicroRNAs (miRs) are a class of single-stranded, non-coding RNAs of ∼22 nucleotides in length, and growing evidence indicates that miRs are implicated in myocardial disease processes. A key pathway involved in heart failure consists of the phosphatase calcineurin and its downstream transcription factor Nuclear Factor of Activated T-cells (NFAT). We performed microRNA profiling in hearts from calcineurin transgenic mice and demonstrated that microRNA-199b (miR-199b) is a direct calcineurin/NFAT target gene. MiR-199b increases in expression in mouse and human heart failure, and targets the nuclear NFAT kinase dual-specificity tyrosine-(Y)-phosphorylation regulated kinase 1a (Dyrk1a), constituting a pathogenic feed forward mechanism with impact on calcineurin-responsive gene expression. Interestingly, cardiac miR-199b levels inversely correlated with cardiac Dyrk1a expression in biopsies of failing human hearts secondary to ischemic heart disease or non-ischemic dilated cardiomyopathy....
Highlight: In this Onlife interview, Professor Pasterkamp talks about current challenges in the a... more Highlight: In this Onlife interview, Professor Pasterkamp talks about current challenges in the atherosclerotic field and the best ways to translate basic science into clinical practice.
The efficiency of the repair process following ischemic cardiac injury is a crucial determinant f... more The efficiency of the repair process following ischemic cardiac injury is a crucial determinant for the progression into heart failure and is controlled by both intra- and intercellular signaling within the heart. An enhanced understanding of this complex interplay will enable better exploitation of these mechanisms for therapeutic use. We used single-cell transcriptomics to collect gene expression data of all main cardiac cell types at different time-points after ischemic injury. These data unveiled cellular and transcriptional heterogeneity and changes in cellular function during cardiac remodeling. Furthermore, we established potential intercellular communication networks after ischemic injury. Follow up experiments confirmed that cardiomyocytes express and secrete elevated levels of beta-2 microglobulin in response to ischemic damage, which can activate fibroblasts in a paracrine manner. Collectively, our data indicate phase-specific changes in cellular heterogeneity during diff...
After the publication of the original article, we noticed that we need a correction in Fig. 2. In... more After the publication of the original article, we noticed that we need a correction in Fig. 2. In the part of the table containing human studies, in Nomura et al. (2018), in the column indicating the type of samples, sham and TAC was now correctly replaced with healthy and DCM. Please see below the corrected version. We apologize for any inconvenience that this may have caused. Publisher's Note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
Purpose of the Review Cardiovascular disease remains the leading cause of death worldwide, result... more Purpose of the Review Cardiovascular disease remains the leading cause of death worldwide, resulting in cardiac dysfunction and, subsequently, heart failure (HF). Single-cell RNA sequencing (scRNA-seq) is a rapidly developing tool for studying the transcriptional heterogeneity in both healthy and diseased hearts. Wide applications of techniques like scRNA-seq could significantly contribute to uncovering the molecular mechanisms involved in the onset and progression to HF and contribute to the development of new, improved therapies. This review discusses several studies that successfully applied scRNA-seq to the mouse and human heart using various methods of tissue processing and downstream analysis. Recent Findings The application of scRNA-seq in the cardiovascular field is continuously expanding, providing new detailed insights into cardiac pathophysiology. Summary Increased understanding of cardiac pathophysiology on the single-cell level will contribute to the development of nove...
Aims Pathological cardiac remodelling is characterized by cardiomyocyte (CM) hypertrophy and fibr... more Aims Pathological cardiac remodelling is characterized by cardiomyocyte (CM) hypertrophy and fibroblast activation, which can ultimately lead to maladaptive hypertrophy and heart failure (HF). Genome-wide expression analysis on heart tissue has been instrumental for the identification of molecular mechanisms at play. However, these data were based on signals derived from all cardiac cell types. Here, we aimed for a more detailed view on molecular changes driving maladaptive CM hypertrophy to aid in the development of therapies to reverse pathological remodelling. Methods and results Utilizing CM-specific reporter mice exposed to pressure overload by transverse aortic banding and CM isolation by flow cytometry, we obtained gene expression profiles of hypertrophic CMs in the more immediate phase after stress, and CMs showing pathological hypertrophy. We identified subsets of genes differentially regulated and specific for either stage. Among the genes specifically up-regulated in the ...
The disruption in blood supply due to myocardial infarction is a critical determinant for infarct... more The disruption in blood supply due to myocardial infarction is a critical determinant for infarct size and subsequent deterioration in function. The identification of factors that enhance cardiac repair by the restoration of the vascular network is, therefore, of great significance. Here, we show that the transcription factor Zinc finger E-box-binding homeobox 2 (ZEB2) is increased in stressed cardiomyocytes and induces a cardioprotective cross-talk between cardiomyocytes and endothelial cells to enhance angiogenesis after ischemia. Single-cell sequencing indicates ZEB2 to be enriched in injured cardiomyocytes. Cardiomyocyte-specific deletion of ZEB2 results in impaired cardiac contractility and infarct healing post-myocardial infarction (post-MI), while cardiomyocyte-specific ZEB2 overexpression improves cardiomyocyte survival and cardiac function. We identified Thymosin β4 (TMSB4) and Prothymosin α (PTMA) as main paracrine factors released from cardiomyocytes to stimulate angiogen...
during the first 24 hours after returning to thermo-neutral conditions. The autophagic flux, dete... more during the first 24 hours after returning to thermo-neutral conditions. The autophagic flux, determined by assessment of LC3b II after leupeptin treatment in vivo, was repressed during cold exposure and strongly reactivated after 24 hours of thermoneutrality. We further confirmed these results using electron microscopy and we found increased abundance of autophagosomes after acute deacclimation. Conclusions: Our data indicates that mice exposed to three weeks of cold develop a marked cardiac hypertrophy, reversed after one week of deacclimation. We propose autophagy as one of the mechanisms leading to heart remodeling in response to cold exposure and its posterior reversion after deacclimation.
Introduction: Diabetes is an independent risk factor for cardiovascular disease, with 50% of diab... more Introduction: Diabetes is an independent risk factor for cardiovascular disease, with 50% of diabetic patients developing cardiomyopathy, including fibrosis. Substance P (SP) is a neuropeptide located in sensory nerves, and diabetic rat hearts have reduced levels of SP. This reduced SP appears to contribute to the loss of cardioprotection in response to ischaemic post conditioning, indicating that SP may play a protective role in diabetic hearts. Purpose: Our aim was to further examine the cardio-protective role of SP in diabetes. We hypothesised that a loss of SP leads to fibrosis in diabetic hearts and that this adverse remodelling is reversible by restoring SP levels. Methods: 10 week old Leprdb obese diabetic mice received a daily subcutaneous injection of either saline or SP (1mg/kg) for four weeks. Wild type C57B/6 mice were included as controls. For in vitro studies, cardiac fibroblasts were isolated and treated with SP (10, 30, 100, 300 and 1000 nM) in high glucose media (DMEM þ 9 g/L of glucose) for 24 hours to mimic diabetes. SP levels were also measured in plasma samples from diabetic patients. Abstract 238 Figure. Collagen Volume Fraction Results: Our results showed that cardiac fibrosis is significantly increased in the Leprdb mouse compared to the wild type group (Figure). This increase in fibrosis was reduced by SP replacement, independent of blood pressure, body weight and blood glucose levels. SP is known to resolve uncontrolled inflammation in diabetic wound healing, however, it did not alter the
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