NRSF-GNAO1 Pathway Contributes to the Regulation of Cardiac Ca 2+ Homeostasis

2021 ◽  
Author(s):  
Hideaki Inazumi ◽  
Koichiro Kuwahara ◽  
Yasuaki Nakagawa ◽  
Yoshihiro Kuwabara ◽  
Takuro Numaga-Tomita ◽  
...  
Keyword(s):  
Heart Failure ◽  
Cardiac Dysfunction ◽  
Molecular Mechanisms ◽  
Systolic Function ◽  
Expression Profiles ◽  
Survival Rates ◽  
Gene Expression Profiles ◽  
Dominant Negative ◽  
Mouse Heart ◽  
Cardiac Gene

Background: During the development of heart failure, a fetal cardiac gene program is reactivated and accelerates pathological cardiac remodeling. We previously reported that a transcriptional repressor, neuron restrictive silencer factor (NRSF), suppresses the fetal cardiac gene program, thereby maintaining cardiac integrity. The underlying molecular mechanisms remains to be determined, however. Methods: We aim to elucidate molecular mechanisms by which NRSF maintains normal cardiac function. We generated cardiac-specific NRSF knockout mice and analyzed cardiac gene expression profiles in those mice and mice cardiac-specifically expressing a dominant-negative NRSF mutant. Results: We found that cardiac expression of Gαo, an inhibitory G protein encoded in humans by GNAO1, is transcriptionally regulated by NRSF and is increased in the ventricles of several mouse models of heart failure. Genetic knockdown of Gnao1 ameliorated the cardiac dysfunction and prolonged survival rates in these mouse heart failure models. Conversely, cardiac-specific overexpression of GNAO1 in mice was sufficient to induce cardiac dysfunction. Mechanistically, we observed that increasing Gαo expression increased surface sarcolemmal L-type Ca 2+ channel activity, activated Calcium/calmodulin-dependent kinase-II (CaMKII) signaling and impaired Ca 2+ handling in ventricular myocytes, which led to cardiac dysfunction. Conclusions: These findings shed light on a novel function of Gαo in the regulation of cardiac Ca 2+ homeostasis and systolic function and suggest Gαo may be an effective therapeutic target for the treatment of heart failure.

Abstract MP170: Increased Ga o Expression Regulated by NRSF Plays a Key Role in the Development of Heart Failure Through the Impairment of Ca 2+ Homeostasis

2020 ◽  
Vol 127 (Suppl_1) ◽  
Author(s):  
Hideaki Inazumi ◽  
Yasuaki Nakagawa ◽  
Kenji Moriuchi ◽  
Koichiro Kuwahara
Keyword(s):  
Heart Failure ◽  
Cardiac Function ◽  
Cardiac Dysfunction ◽  
Intracellular Signaling ◽  
Molecular Mechanisms ◽  
Troponin T ◽  
Dominant Negative ◽  
Dominant Negative Mutant ◽  
Cardiac Gene ◽  
Normal Cardiac Function

Background: In the development of heart failure, pathological intracellular signaling reactivates fetal cardiac gene program, which leads to pathological cardiac remodeling. We previously reported that a transcriptional repressor, neuron restrictive silencer factor (NRSF) represses fetal cardiac gene program and maintains normal cardiac function, while pathological stimuli de-repress this NRSF mediated repression via activation of CaMKII. Molecular mechanisms by which NRSF maintains cardiac function remains to be determined, however. Purpose: To elucidate molecular mechanisms by which NRSF maintains normal cardiac function. Methods and Results: Newly generated cardiac-specific NRSF knockout mice (NRSF-cKO) showed cardiac dysfunction and premature deaths accompanied with lethal arrhythmias, as was observed in our previously reported cardiac-specific dominant-negative mutant of NRSF transgenic mice (dnNRSF-Tg). Expression of Gnao1 gene encoding Gα o , a member of inhibitory G proteins, was commonly increased in ventricles of dnNRSF-Tg and NRSF-cKO. ChIP-seq analysis, reporter assay and electrophoretic mobility shift assay identified that NRSF transcriptionally regulates Gnao1 gene expression. Genetic Knockdown of Gα o in dnNRSF-Tg and NRSF-cKO ameliorated the reduced systolic function, increased arrhythmogenicity and reduced survival rates. Conversely cardiac-specific GNAO1 overexpression was sufficient to show impaired cardiac function. Mechanistically, Gα o increases current density in surface sarcolemmal L-type Ca 2 + channel and then activates CaMKII without affecting protein kinase A activity, which finally leads to impaired Ca 2+ handling and systolic dysfunction. Furthermore, expression of Gα o is also increased in ventricles of transverse aortic constriction model mice and cardiac troponin T mutant DCM model mice, in both of which, genetic reduction of Gα o prevented the progression of cardiac dysfunction. Conclusions: Increased expression of Gα o , induced by attenuation of NRSF-mediated repression forms a pathological circuit via activation of CaMKII and progresses heart failure by impairing Ca 2+ homeostasis. Gα o is a potential therapeutic target for heart failure.

NRSF-GNAO1-CaMK2 axis exacerbates cardiac remodeling and progresses heart failure by impairing Ca2+ homeostasis

2020 ◽  
Vol 41 (Supplement_2) ◽  
Author(s):  
H Inazumi ◽  
K Kuwahara ◽  
Y Kuwabara ◽  
Y Nakagawa ◽  
H Kinoshita ◽  
...  
Keyword(s):  
Heart Failure ◽  
Transgenic Mice ◽  
Knockout Mice ◽  
Cardiac Remodeling ◽  
Cardiac Dysfunction ◽  
Intracellular Signaling ◽  
Molecular Mechanisms ◽  
Systolic Function ◽  
Dominant Negative Mutant ◽  
Funding Source

Abstract Background In the development of heart failure, pathological intracellular signaling reactivates fetal cardiac genes, which leads to maladaptive remodeling and cardiac dysfunction. We previously reported that a transcriptional repressor, neuron restrictive silencer factor (NRSF) represses fetal cardiac genes and maintains normal cardiac function under normal conditions, while hypertrophic stimuli de-repress this NRSF mediated repression via activation of CaMKII. Molecular mechanisms by which NRSF maintains cardiac systolic function remains to be determined, however. Purpose To elucidate how NRSF maintains normal cardiac homeostasis and identify the novel therapeutic targets for heart failure. Methods and results We generated cardiac-specific NRSF knockout mice (NRSF cKO), and found that these NRSF cKO showed cardiac dysfunction and premature deaths accompanied with lethal arrhythmias, as was observed in our previously reported cardiac-specific dominant-negative mutant of NRSF transgenic mice (dnNRSF-Tg). By cDNA microarray analysis of dnNRSF-Tg and NRSF-cKO, we identified that expression of Gnao1 gene encoding Gαo, a member of inhibitory G proteins, was commonly increased in ventricles of both types of mice. ChIP-seq analysis, reporter assay and electrophoretic mobility shift assay identified that NRSF transcriptionally regulates Gnao1 gene expression. Genetic Knockdown of Gαo in dnNRSF-Tg and NRSF-cKO by crossing these mice with Gnao1 knockout mice ameliorated the reduced systolic function, increased arrhythmogenicity and reduced survival rates. Transgenic mice expressing a human GNAO1 in their hearts (GNAO1-Tg) showed progressive cardiac dysfunction with cardiac dilation. Ventricles obtained from GNAO1-Tg have increased phosphorylation level of CaMKII and increased expression level of endogenous mouse Gnao1 gene. These data suggest that increased cardiac expression of Gαo is sufficient to induce pathological Ca2+-dependent signaling and cardiac dysfunction, and that Gαo forms a positive regulatory circuit with CaMKII and NRSF. Electrophysiological analysis in ventricular myocytes of dnNRSF-Tg revealed that impaired Ca2+ handling via alterations in localized L-type calcium channel (LTCC) activities; decreased T-tubular and increased surface sarcolemmal LTCC activities, underlies Gαo-mediated cardiac dysfunction. Furthermore, we also identified increased expression of Gαo in ventricles of two different heart failure mice models, mice with transverse aortic constriction and mice carrying a mutant cardiac troponin T, and confirmed that genetic reduction of Gαo prevented the progression of cardiac dysfunction in both types of mice. Conclusions Increased expression of Gαo, induced by attenuation of NRSF-mediated repression forms a pathological circuit via activation of CaMKII. This circuit exacerbates cardiac remodeling and progresses heart failure by impairing Ca2+ homeostasis. Gαo is a potential therapeutic target for heart failure. Figure 1 Funding Acknowledgement Type of funding source: Public grant(s) – National budget only. Main funding source(s): Grants-in –Aid for Scientific Research from the Japan Society for the Promotion of Science

scholarly journals Effects of vitamin A deficiency in the postnatal mouse heart: role of hepatic retinoid stores

2016 ◽  
Vol 310 (11) ◽  
pp. H1773-H1789 ◽  
Author(s):  
Mary Ann Asson-Batres ◽  
Sergey Ryzhov ◽  
Oleg Tikhomirov ◽  
Christine W. Duarte ◽  
Clare Bates Congdon ◽  
...  
Keyword(s):  
Myocardial Infarction ◽  
Vitamin A ◽  
Systolic Function ◽  
Vitamin A Deficiency ◽  
Expression Profiles ◽  
Flow Cytometric Analysis ◽  
Gene Expression Profiles ◽  
In Silico Analysis ◽  
Mouse Heart ◽  
Adverse Remodeling

To determine whether hepatic depletion of vitamin A (VA) stores has an effect on the postnatal heart, studies were carried out with mice lacking liver retinyl ester stores fed either a VA-sufficient (LRVAS) or VA-deficient (LRVAD) diet (to deplete circulating retinol and extrahepatic stores of retinyl esters). There were no observable differences in the weights or gross morphology of hearts from LRVAS or LRVAD mice relative to sex-matched, age-matched, and genetically matched wild-type (WT) controls fed the VAS diet (WTVAS), but changes in the transcription of functionally relevant genes were consistent with a state of VAD in LRVAS and LRVAD ventricles. In silico analysis revealed that 58/67 differentially expressed transcripts identified in a microarray screen are products of genes that have DNA retinoic acid response elements. Flow cytometric analysis revealed a significant and cell-specific increase in the number of proliferating Sca-1 cardiac progenitor cells in LRVAS animals relative to WTVAS controls. Before myocardial infarction, LRVAS and WTVAS mice had similar cardiac systolic function and structure, as measured by echocardiography, but, unexpectedly, repeat echocardiography demonstrated that LRVAS mice had less adverse remodeling by 1 wk after myocardial infarction. Overall, the results demonstrate that the adult heart is responsive to retinoids, and, most notably, reducing hepatic VA stores (while maintaining circulating levels of VA) impacts ventricular gene expression profiles, progenitor cell numbers, and response to injury.

scholarly journals Citri Reticulatae Pericarpium Alleviates Postmyocardial Infarction Heart Failure by Upregulating Pparγ Expression

2021 ◽  
Author(s):  
Mengli Chen ◽  
Hongyan Zhu ◽  
Qingqing Zhu ◽  
Xiaodong Wu ◽  
Yufei Zhou ◽  
...  
Keyword(s):  
Heart Failure ◽  
Cardiac Hypertrophy ◽  
Molecular Mechanisms ◽  
Systolic Function ◽  
Tunel Staining ◽  
Mouse Heart ◽  
Coronary Artery Ligation ◽  
Traditional Chinese Herbal Medicine

Abstract PurposeHeart failure after myocardial infarction (MI) is the leading cause of death worldwide. Citri Reticulatae Pericarpium (CRP) is a traditional Chinese herbal medicine that has been used in the clinic for centuries. In this study, we aimed to investigate the roles of CRP in cardiac remodeling and heart failure after MI, as well as the molecular mechanisms involved.MethodsMale C57BL/6 mice aged 8 weeks were subjected to coronary artery ligation to mimic the clinical situation in vivo. Echocardiography was used to assess the systolic function of the mouse heart. Masson trichrome staining and Wheat germ agglutinin (WGA) staining were utilized to determine the fibrotic area and cross-sectional area of the mouse heart, respectively. Cardiomyocytes and fibroblasts were isolated from neonatal rats aged 0–3 days in vitro using enzyme digestion. TUNEL staining and EdU staining were performed to evaluate apoptosis and proliferation, respectively. Gene expression changes were analyzed by qRT–PCR, and protein expression changes were assessed by Western blotting.ResultsOur findings revealed that CRP attenuated cardiac hypertrophy, fibrosis and apoptosis and alleviated heart failure after MI in vivo. Furthermore, CRP mitigated cardiomyocyte apoptosis and fibroblast proliferation and differentiation into myofibroblasts. In addition, the PPARγ inhibitor T0070907 completely abolished the abovementioned beneficial effects of CRP, and the PPARγ activator rosiglitazone failed to further ameliorate cardiac apoptosis and fibrosis in vitro.ConclusionCRP alleviates cardiac hypertrophy, fibrosis, and apoptosis and can ameliorate heart failure after MI via activation of PPARγ.

Distinct gene expression profiles in adult mouse heart following targeted MAP kinase activation

2006 ◽  
Vol 25 (1) ◽  
pp. 50-59 ◽  
Author(s):  
Scherise Mitchell ◽  
Asuka Ota ◽  
William Foster ◽  
Bin Zhang ◽  
Zixing Fang ◽  
...  
Keyword(s):  
Gene Expression ◽  
Heart Failure ◽  
Map Kinase ◽  
Expression Profiles ◽  
Expression Patterns ◽  
Gene Expression Profiles ◽  
Mouse Heart ◽  
Matrix Remodeling ◽  
Long Term Effects ◽  
Kinase Activation

Three major MAP kinase signaling cascades, ERK, p38, and JNK, play significant roles in the development of cardiac hypertrophy and heart failure in response to external stress and neural/hormonal stimuli. To study the specific function of each MAP kinase branch in adult heart, we have generated three transgenic mouse models with cardiac-specific and temporally regulated expression of activated mutants of Ras, MAP kinase kinase (MKK)3, and MKK7, which are selective upstream activators for ERK, p38, and JNK, respectively. Gene expression profiles in transgenic adult hearts were determined using cDNA microarrays at both early (4–7 days) and late (2–4 wk) time points following transgene induction. From this study, we revealed common changes in gene expression among the three models, particularly involving extracellular matrix remodeling. However, distinct expression patterns characteristic for each pathway were also identified in cell signaling, growth, and physiology. In addition, genes with dynamic expression differences between early vs. late stages illustrated primary vs. secondary changes on MAP kinase activation in adult hearts. These results provide an overview to both short-term and long-term effects of MAP kinase activation in heart and support some common as well as unique roles for each MAP kinase cascade in the development of heart failure.

scholarly journals Modulation of the Immune Response by Deferasirox in Myelodysplastic Syndrome Patients

2021 ◽  
Vol 14 (1) ◽  
pp. 41
Author(s):  
Hana Votavova ◽  
Zuzana Urbanova ◽  
David Kundrat ◽  
Michaela Dostalova Merkerova ◽  
Martin Vostry ◽  
...  
Keyword(s):  
Gene Expression ◽  
Immune Response ◽  
Blood Cell ◽  
Myelodysplastic Syndrome ◽  
Molecular Mechanisms ◽  
Expression Profiles ◽  
Adaptive Immune Response ◽  
Gene Expression Profiles ◽  
Iron Chelator ◽  
Multiple Cancer

Deferasirox (DFX) is an oral iron chelator used to reduce iron overload (IO) caused by frequent blood cell transfusions in anemic myelodysplastic syndrome (MDS) patients. To study the molecular mechanisms by which DFX improves outcome in MDS, we analyzed the global gene expression in untreated MDS patients and those who were given DFX treatment. The gene expression profiles of bone marrow CD34+ cells were assessed by whole-genome microarrays. Initially, differentially expressed genes (DEGs) were determined between patients with normal ferritin levels and those with IO to address the effect of excessive iron on cellular pathways. These DEGs were annotated to Gene Ontology terms associated with cell cycle, apoptosis, adaptive immune response and protein folding and were enriched in cancer-related pathways. The deregulation of multiple cancer pathways in iron-overloaded patients suggests that IO is a cofactor favoring the progression of MDS. The DEGs between patients with IO and those treated with DFX were involved predominantly in biological processes related to the immune response and inflammation. These data indicate DFX modulates the immune response mainly via neutrophil-related genes. Suppression of negative regulators of blood cell differentiation essential for cell maturation and upregulation of heme metabolism observed in DFX-treated patients may contribute to the hematopoietic improvement.

scholarly journals Chamber-enriched gene expression profiles in failing human hearts with reduced ejection fraction

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Xin Luo ◽  
Jun Yin ◽  
Denise Dwyer ◽  
Tracy Yamawaki ◽  
Hong Zhou ◽  
...  
Keyword(s):  
Heart Failure ◽  
Ejection Fraction ◽  
Human Genetics ◽  
Expression Profiles ◽  
Gene Expression Profiles ◽  
Left Heart ◽  
Reduced Ejection Fraction ◽  
Cell Type Composition ◽  
Type Composition ◽  
Underlying Mechanisms

AbstractHeart failure with reduced ejection fraction (HFrEF) constitutes 50% of HF hospitalizations and is characterized by high rates of mortality. To explore the underlying mechanisms of HFrEF etiology and progression, we studied the molecular and cellular differences in four chambers of non-failing (NF, n = 10) and HFrEF (n = 12) human hearts. We identified 333 genes enriched within NF heart subregions and often associated with cardiovascular disease GWAS variants. Expression analysis of HFrEF tissues revealed extensive disease-associated transcriptional and signaling alterations in left atrium (LA) and left ventricle (LV). Common left heart HFrEF pathologies included mitochondrial dysfunction, cardiac hypertrophy and fibrosis. Oxidative stress and cardiac necrosis pathways were prominent within LV, whereas TGF-beta signaling was evident within LA. Cell type composition was estimated by deconvolution and revealed that HFrEF samples had smaller percentage of cardiomyocytes within the left heart, higher representation of fibroblasts within LA and perivascular cells within the left heart relative to NF samples. We identified essential modules associated with HFrEF pathology and linked transcriptome discoveries with human genetics findings. This study contributes to a growing body of knowledge describing chamber-specific transcriptomics and revealed genes and pathways that are associated with heart failure pathophysiology, which may aid in therapeutic target discovery.

Dorsal Root Ganglion Neuron Types and Their Functional Specialization

2018 ◽  
pp. 127-155 ◽  
Author(s):  
Edward C. Emery ◽  
Patrik Ernfors
Keyword(s):  
Chronic Pain ◽  
Dorsal Root Ganglion ◽  
Sensory Neurons ◽  
Dorsal Root ◽  
Molecular Mechanisms ◽  
Expression Profiles ◽  
Gene Expression Profiles ◽  
Drg Neurons ◽  
Low Threshold

Primary sensory neurons of the dorsal root ganglion (DRG) respond and relay sensations that are felt, such as those for touch, pain, temperature, itch, and more. The ability to discriminate between the various types of stimuli is reflected by the existence of specialized DRG neurons tuned to respond to specific stimuli. Because of this, a comprehensive classification of DRG neurons is critical for determining exactly how somatosensation works and for providing insights into cell types involved during chronic pain. This article reviews the recent advances in unbiased classification of molecular types of DRG neurons in the perspective of known functions as well as predicted functions based on gene expression profiles. The data show that sensory neurons are organized in a basal structure of three cold-sensitive neuron types, five mechano-heat sensitive nociceptor types, four A-Low threshold mechanoreceptor types, five itch-mechano-heat–sensitive nociceptor types and a single C–low-threshold mechanoreceptor type with a strong relation between molecular neuron types and functional types. As a general feature, each neuron type displays a unique and predicable response profile; at the same time, most neuron types convey multiple modalities and intensities. Therefore, sensation is likely determined by the summation of ensembles of active primary afferent types. The new classification scheme will be instructive in determining the exact cellular and molecular mechanisms underlying somatosensation, facilitating the development of rational strategies to identify causes for chronic pain.

scholarly journals Transcriptome-wide gene expression plasticity in Stipa grandis in response to grazing intensity differences

2020 ◽  
Author(s):  
Zhenhua Dang ◽  
Yuanyuan Jia ◽  
Yunyun Tian ◽  
Jiabin Li ◽  
Yanan Zhang ◽  
...  
Keyword(s):  
Gene Expression ◽  
Metabolic Pathways ◽  
Molecular Mechanisms ◽  
Expression Profiles ◽  
Gene Expression Profiles ◽  
Grazing Intensity ◽  
Glycolate Oxidase ◽  
Bisphosphate Carboxylase ◽  
Grazing Intensities

Organisms have evolved effective and distinct adaptive strategies to survive. Stipa grandis is one of the widespread dominant species on the typical steppe of the Inner Mongolian Plateau, and is regarded as a suitable species for studying the effects of grazing in this region. Although phenotypic (morphological and physiological) variations in S. grandis in response to long-term grazing have been identified, the molecular mechanisms underlying adaptations and plastic responses remain largely unknown. Accordingly, we performed a transcriptomic analysis to investigate changes in gene expression of S. grandis under four different grazing intensities. A total of 2,357 differentially expressed genes (DEGs) were identified among the tested grazing intensities, suggesting long-term grazing resulted in gene expression plasticity that affected diverse biological processes and metabolic pathways in S. grandis. DEGs were identified that indicated modulation of Calvin–Benson cycle and photorespiration metabolic pathways. The key gene´expression profiles encoding various proteins (e.g., Ribulose-1,5-bisphosphate carboxylase/oxygenase, fructose-1,6-bisphosphate aldolase, glycolate oxidase etc.) involved in these pathways suggest that they may synergistically respond to grazing to increase the resilience and stress tolerance of S. grandis. Our findings provide scientific clues for improving grassland use and protection, and identify important questions to address in future transcriptome studies.

scholarly journals Transcriptome resequencing analysis of the responses of Ty-5-Mediated resistance to TYLCV via in resistant vs. susceptible tomato cultivars

2018 ◽  
Author(s):  
Qingqi Chen ◽  
Xiangyang Xu ◽  
Jingbin Jiang ◽  
Jingfu Li
Keyword(s):  
Molecular Mechanisms ◽  
Carbon Fixation ◽  
Expression Profiles ◽  
Gene Expression Profiles ◽  
Glutathione Metabolism ◽  
Functional Classification ◽  
Wild Tomato Species ◽  
Tomato Species ◽  
Tomato Cultivars ◽  
Susceptible Tomato

Tomato yellow leaf curl virus (TYLCV) is one of the most devastating viruses of cultivated tomato in both tropical and subtropical regions. Five major genes (Ty-1, Ty-2, Ty-3, Ty-4 and Ty-5) from wild tomato species have been associated with resistance to TYLCV. Researchers have recently attempted to determine the functions of these resistance genes, but molecular mechanisms underlying the observed resistance remain unclear. Here, resistant (cv. CLN3212A-23, carrying Ty-5) and susceptible (cv. Moneymaker) plants were either left untreated (R and S, respectively) or artificially inoculated with TYLCV via Agrobacterium-mediated transformation (RT and ST, respectively). The transcriptomes of the plants in the four groups were then analyzed by RNA-Seq, and the results identified 8,639 differentially expressed genes (DEGs) between the R and RT groups, 2,818 DEGs between the RT and ST groups, 8,899 DEGs between the S and ST groups, and 707 DEGs between the R and S groups. The gene expression profiles in both the resistant and susceptible tomato cultivars appeared to undergo notable changes after viral inoculation, and functional classification revealed that most DEGs were associated with 18 GO terms. Moreover, the functional classification of the response of Ty-5-carrying tomato plants to TYLCV infection identified the importance of the GO term “response to stimulus” in the BP category, which is related to disease resistance. In addition, 28 genes were significantly enriched in the “Plant hormone signal transduction”, “Carbon metabolism”, “ Carbon fixation in photosynthetic organisms ” and “ Glutathione metabolism ” pathways. The differential expression levels of 12 select genes were confirmed by quantitative real-time PCR. The present study indicates that the Ty-5 gene activates the expression of multiple genes involved in the resistance process and will aid a more in-depth understanding of the effects of the Ty-5 gene on resistance based on its molecular mechanism with the aim of improving TYLCV disease management in tomato.

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