Bulk RNA-sequencing of murine atrioventricular nodes
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ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE86306 | GEO | 2017/04/20
REPOSITORIES: GEO
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Project description:Tissue-resident macrophages abound in the distal atrioventricular (AV) node of the heart, electrically couple to conducting cardiomyocytes via Connexin (Cx) 43-containing gap junctions and are implicated in normal and aberrant cardiac conduction.
2017-04-20 | GSE86310 | GEO
Project description:Heart failure is associated with atrioventricular (AV) node dysfunction, and AV node dysfunction in the setting of heart failure is associated with an increased risk of mortality and heart failure hospitalisation. This study aims to understand the causes of AV node dysfunction in heart failure by studying changes in the whole nodal transcriptome. The mouse transverse aortic constriction model of heart failure was studied; functional changes were assessed using electrocardiography and echocardiography and the transcriptome of the AV node was quantified using RNA-seq. Heart failure was associated with a significant increase in the PR interval, indicating a slowing of AV node conduction and AV node dysfunction, and significant changes in 3,077 transcripts (5.6% of the transcriptome). Many systems were affected: transcripts supporting AV node conduction were downregulated and there were changes in transcripts identified by GWAS as determinants of the PR interval. In addition, there was evidence of remodelling of the sarcomere, a shift from fatty acid to glucose metabolism, and remodelling of the extracellular matrix. There was evidence of the causes of this widespread remodelling of the AV node: evidence of dysregulation of multiple intracellular signalling pathways, dysregulation of 109 protein kinases and 148 transcription factors, and an immune response with a proliferation of neutrophils, monocytes, macrophages and B lymphocytes and a dysregulation of 40 cytokines. In conclusion, inflammation and a widespread transcriptional remodelling of the AV node underlies AV node dysfunction in heart failure.
2023-02-08 | E-MTAB-12384 | biostudies-arrayexpress
Project description:The atrioventricular (AV) node is a recurrent source of potentially life-threatening arrhythmias. Nevertheless, limited data are available on its developmental control or molecular phenotype. We used a novel AV node-specific reporter mouse to gain insight into the gene programs determining the formation and phenotype of the AV node. In the transgenic reporter, green fluorescent protein (GFP) expression was driven by 160 kbp of Tbx3 and flanking sequences. GFP was selectively expressed in the AV canal of embryos, and in the AV node of adults, while all other Tbx3+ conduction system components, including the AV bundle, were devoid of GFP expression. Fluorescent AV nodal (Tbx3BAC-Egfp) and complementary working (NppaBAC336-Egfp) myocardial cell populations of E10.5 embryos and E17.5 fetuses were purified using fluorescence-activated cell sorting, and their expression profiles were assessed by microarray analysis. We constructed a comprehensive list of sodium, calcium, and potassium channels specific for the nodal or working myocard. Furthermore, the data revealed that the AV node and the working myocardium phenotypes diverge during development, but that the functional gene classes characteristic for both compartments are maintained. Interestingly, the AV node-specific gene repertoire consisted of multiple neurotrophic factors not yet appreciated to play a role in nodal development. These data present the first genome-wide transcription profiles of the AV node during development, providing valuable information concerning its molecular identity. Keywords: Tbx3, AV node, working myocardium, embryonic development, cardiac development, cardiac conduction system 24 samples: 6x working myocardium stage E10.5 (NppaBAC336-Egfp mice), 6x AV canal myocardium stage E10.5 (Tbx3BAC-Egfp mice), 6x working myocardium stage E17.5 (NppaBAC336-Egfp mice), 6x AV node myocardium stage E17.5 (Tbx3BAC-Egfp mice)
2009-06-02 | E-GEOD-13614 | biostudies-arrayexpress
Project description:The atrioventricular (AV) node is a recurrent source of potentially life-threatening arrhythmias. Nevertheless, limited data are available on its developmental control or molecular phenotype. We used a novel AV node-specific reporter mouse to gain insight into the gene programs determining the formation and phenotype of the AV node. In the transgenic reporter, green fluorescent protein (GFP) expression was driven by 160 kbp of Tbx3 and flanking sequences. GFP was selectively expressed in the AV canal of embryos, and in the AV node of adults, while all other Tbx3+ conduction system components, including the AV bundle, were devoid of GFP expression. Fluorescent AV nodal (Tbx3BAC-Egfp) and complementary working (NppaBAC336-Egfp) myocardial cell populations of E10.5 embryos and E17.5 fetuses were purified using fluorescence-activated cell sorting, and their expression profiles were assessed by microarray analysis. We constructed a comprehensive list of sodium, calcium, and potassium channels specific for the nodal or working myocard. Furthermore, the data revealed that the AV node and the working myocardium phenotypes diverge during development, but that the functional gene classes characteristic for both compartments are maintained. Interestingly, the AV node-specific gene repertoire consisted of multiple neurotrophic factors not yet appreciated to play a role in nodal development. These data present the first genome-wide transcription profiles of the AV node during development, providing valuable information concerning its molecular identity. Keywords: Tbx3, AV node, working myocardium, embryonic development, cardiac development, cardiac conduction system
2009-06-02 | GSE13614 | GEO
Project description:Rationale: The atrioventricular conduction system controls ventricular activation and is delineated by expression of Tbx3. Genome-wide association studies identified genetic variants near TBX3 associated with conduction velocities (PR interval and QRS duration), suggesting minor changes in TBX3 dose affect conduction system function. Objective: To assess whether and how Tbx3 dose reduction affects the integrity of the atrioventricular conduction system. Methods and Results: Electrocardiograms revealed a PR interval shortening and prolonged QT interval and QRS duration in heterozygous Tbx3 mutants compared to wild-types. We observed that the atrioventricular bundle and proximal bundle branches of Tbx3+/- mice after birth became hypoplastic, whereas the size of the atrioventricular node was not affected. The transcriptomes of wild-type and Tbx3+/- atrioventricular nodes were analyzed using BAC-Tbx3-Egfp mice enabling specific isolation of the atrioventricular node by laser capture microdissection followed by RNA-sequencing. Hundreds of genes were slightly but consistently deregulated. Cross-referencing with transcriptome data of isolated cardiomyocytes of the conduction system and chamber myocardium derived from Tbx3+/Venus;BAC-Nppb-Katushka hearts revealed that a set of chamber-enriched genes, including Kcne1 (MinK), Ryr2, and Scn5a, were upregulated in Tbx3+/- atrioventricular nodes, whereas conduction system-enriched genes, including Hcn4 and Cacna2d2, were downregulated. We performed ATAC-sequencing on purified fetal Tbx3+ atrioventricular cardiomyocytes to identify potential atrioventricular-specific regulatory DNA elements on a genome-wide scale, and identified regulatory elements mediating the Tbx3-dependent regulation of Ryr2 and other target genes in the atrioventricular node. Conclusions: Tbx3 dose reduction results in deregulation of a large number of genes affecting the electrical properties of the atrioventricular node and causes failure to maintain the structural integrity of the atrioventricular bundle. These data provide a mechanism underlying differences in PR interval and QRS duration in individuals carrying associated variants in the TBX3 locus.
2019-10-18 | GSE121464 | GEO
Project description:Rationale: The atrioventricular conduction system controls ventricular activation and is delineated by expression of Tbx3. Genome-wide association studies identified genetic variants near TBX3 associated with conduction velocities (PR interval and QRS duration), suggesting minor changes in TBX3 dose affect conduction system function. Objective: To assess whether and how Tbx3 dose reduction affects the integrity of the atrioventricular conduction system. Methods and Results: Electrocardiograms revealed a PR interval shortening and prolonged QT interval and QRS duration in heterozygous Tbx3 mutants compared to wild-types. We observed that the atrioventricular bundle and proximal bundle branches of Tbx3+/- mice after birth became hypoplastic, whereas the size of the atrioventricular node was not affected. The transcriptomes of wild-type and Tbx3+/- atrioventricular nodes were analyzed using BAC-Tbx3-Egfp mice enabling specific isolation of the atrioventricular node by laser capture microdissection followed by RNA-sequencing. Hundreds of genes were slightly but consistently deregulated. Cross-referencing with transcriptome data of isolated cardiomyocytes of the conduction system and chamber myocardium derived from Tbx3+/Venus;BAC-Nppb-Katushka hearts revealed that a set of chamber-enriched genes, including Kcne1 (MinK), Ryr2, and Scn5a, were upregulated in Tbx3+/- atrioventricular nodes, whereas conduction system-enriched genes, including Hcn4 and Cacna2d2, were downregulated. We performed ATAC-sequencing on purified fetal Tbx3+ atrioventricular cardiomyocytes to identify potential atrioventricular-specific regulatory DNA elements on a genome-wide scale, and identified regulatory elements mediating the Tbx3-dependent regulation of Ryr2 and other target genes in the atrioventricular node. Conclusions: Tbx3 dose reduction results in deregulation of a large number of genes affecting the electrical properties of the atrioventricular node and causes failure to maintain the structural integrity of the atrioventricular bundle. These data provide a mechanism underlying differences in PR interval and QRS duration in individuals carrying associated variants in the TBX3 locus.
2019-10-18 | GSE121244 | GEO
Project description:Rationale: A critical step in heart development is the coordinated formation of nodal myocardium and cushion tissue from the atrioventricular canal (AVC). After its specification, the myocardium of the AVC aligns the chambers, forms the AV node, and induces the formation of the mesenchymal AV cushions, primordia of valves and septa, while it resists working myocardial differentiation. Objective: To assess what roles Tbx2 and Tbx3, two closely related T-box transcription factors expressed in the AVC, play in these processes. Methods and Results: We analyzed mice ectopically expressing Tbx3 in the atrial myocardium by genome-wide microarray and expression analysis. We found a prominent role for Tbx3 in defining the nodal phenotype by repressing working myocardial genes (sarcomeric, mitochondrial, fast conduction) and cell proliferation regulators, and in inducing node-associated genes. Moreover, there was a striking induction of genes associated with endocardial cushions and mesenchyme. Using gain-of-function models, we found that in the developing heart both Tbx2 and Tbx3 induce ectopic Bmp2 and Tgfb2 expression and endocardial cushion formation. Analysis of compound Tbx2/Tbx3 mutant embryos revealed that upon loss of more than two functional alleles, expansion of the AV myocardium does not occur and AV cushions fail to form. Conclusions: Tbx2 and Tbx3 locally stimulate development of the AVC myocardium, induce the AV nodal phenotype therein and trigger AV cushion formation from the overlying AV endocardium, providing a mechanism for the colocalization and coordination of these two important processes in heart development.
2014-08-01 | GSE10318 | GEO
Project description:Rationale: A critical step in heart development is the coordinated formation of nodal myocardium and cushion tissue from the atrioventricular canal (AVC). After its specification, the myocardium of the AVC aligns the chambers, forms the AV node, and induces the formation of the mesenchymal AV cushions, primordia of valves and septa, while it resists working myocardial differentiation. Objective: To assess what roles Tbx2 and Tbx3, two closely related T-box transcription factors expressed in the AVC, play in these processes. Methods and Results: We analyzed mice ectopically expressing Tbx3 in the atrial myocardium by genome-wide microarray and expression analysis. We found a prominent role for Tbx3 in defining the nodal phenotype by repressing working myocardial genes (sarcomeric, mitochondrial, fast conduction) and cell proliferation regulators, and in inducing node-associated genes. Moreover, there was a striking induction of genes associated with endocardial cushions and mesenchyme. Using gain-of-function models, we found that in the developing heart both Tbx2 and Tbx3 induce ectopic Bmp2 and Tgfb2 expression and endocardial cushion formation. Analysis of compound Tbx2/Tbx3 mutant embryos revealed that upon loss of more than two functional alleles, expansion of the AV myocardium does not occur and AV cushions fail to form. Conclusions: Tbx2 and Tbx3 locally stimulate development of the AVC myocardium, induce the AV nodal phenotype therein and trigger AV cushion formation from the overlying AV endocardium, providing a mechanism for the colocalization and coordination of these two important processes in heart development. Nppa-Cre4 (Cre4) mice were crossed with CT mice to obtain efficient activation of Tbx3 in atria of double transgenic Cre4-CT mice, as previously described (Hoogaars et al., 2007). To investigate the gene expression profile of atria of Cre4-CT mice, we performed whole genome microarray analysis using Sentrix Mouse-6 oligonucleotide beadchips. We compared the atrial gene expression profiles of six male double transgenic Cre4-CT mice and six male Cre4 control mice.
2014-08-01 | E-GEOD-10318 | biostudies-arrayexpress
Project description:Goals of this study were to identify new candidates involved in the development of the Atrioventricular cushions in the mouse heart. Experiment Overall Design: The atrioventricular junction and ventricular region were dissected from 80 embryonic day 10.5-11.0, wild type, C57BL/6 mouse hearts. RNA was isolated from the respective regions, amplified using the Arcturus RiboAmp HS RNA amplification kit, and hybridized to Affymetrix MOE430A expression chips in duplicate. Comparison between atrioventricular gene expression and ventricular gene expression will allow for the identification of genes necessary in the development of the AV cushions.
2008-06-13 | E-GEOD-4903 | biostudies-arrayexpress
Project description:The atrioventricular canal (AVC) is the site where key structures responsible for functional division between heart regions are established, most importantly, the atrioventricular (AV) conduction system and cardiac valves. To elucidate the mechanism underlying AVC development and function, we utilized transgenic zebrafish line sqet31Et expressing EGFP in the AVC to isolate this cell population and profile its transcriptome at 48 and 72 hpf. The zebrafish AVC transcriptome exhibits hallmarks of mammalian AV node, including the expression of genes implicated in its development and those encoding connexins forming low conductance gap junctions. Transcriptome analysis uncovered protein-coding and noncoding transcripts enriched in AVC, which have not been previously associated with this structure, as well as dynamic expression of epithelial-to-mesenchymal transition markers and components of TGF-β, Notch, and Wnt signaling pathways likely reflecting ongoing AVC and valve development. Using transgenic line Tg(myl7:mermaid) encoding voltage-sensitive fluorescent protein, we show that abolishing the pacemaker-containing sinoatrial ring (SAR) through Isl1 loss of function resulted in spontaneous activation in the AVC region, suggesting that it possesses inherent automaticity although insufficient to replace the SAR. The SAR and AVC transcriptomes express partially overlapping species of ion channels and gap junction proteins, reflecting their distinct roles. Besides identifying conserved aspects between zebrafish and mammalian conduction systems, our results established molecular hallmarks of the developing AVC which underlies its role in structural and electrophysiological separation between heart chambers. This data constitutes a valuable resource for studying AVC development and function, and identification of novel candidate genes implicated in these processes.
2021-09-24 | GSE160107 | GEO