Project description:Ischemic cardiomyopathy (ICM) leads to congestive heart failure and can cause sudden cardiac death due to arrhythmia. Existing molecular knowledge base of ICM is rudimentary because of lack of specific attribution to cell type and function. This study was designed to investigate cell-specific molecular remodeling of ion channels, exchangers and pumps, which are signaling molecules (SM) involved in electrical, signaling and mechanical functions of the heart. Atrial and ventricular myocytes were isolated by laser-capture microdissection from left atrium and ventricle of healthy and ICM human hearts. SM and their splice variants altered by ICM in cardiomyocytes were identified by splice microarray and validated by RT-PCR. Molecular profiling of ICM-related changes showed that SM in atrial and ventricular myocytes remodel following their unique programs. ICM affected 63 genes in ventricular myocytes and 12 genes in atrial myocytes. Only few of the identified genes were previously linked to human cardiac disfunctions. In our experiments we used 3 healthy hearts rejected from transplantation procedure and explanted ICM hearts from three male patients. Tissue samples were dissected from left ventricle and left atrial appendages. Atrial and ventricular myocytes were laser-capture microdissected from serial 7-8-µm thick cryostat sections. Individual cellular total RNA samples were analyzed on custom-built Human Ion Channel Splice Arrays slides (ExonHit) manufactured on the Ion Channel Splice Array sv1.1 platform representing 287 human SM, including 248 alternatively spliced ones in total 1655 splicing events and supplemented with capabilities to recognize connexins and ryanodine receptors.
Project description:Ischemic cardiomyopathy (ICM) leads to congestive heart failure and can cause sudden cardiac death due to arrhythmia. Existing molecular knowledge base of ICM is rudimentary because of lack of specific attribution to cell type and function. This study was designed to investigate cell-specific molecular remodeling of ion channels, exchangers and pumps, which are signaling molecules (SM) involved in electrical, signaling and mechanical functions of the heart. Atrial and ventricular myocytes were isolated by laser-capture microdissection from left atrium and ventricle of healthy and ICM human hearts. SM and their splice variants altered by ICM in cardiomyocytes were identified by splice microarray and validated by RT-PCR. Molecular profiling of ICM-related changes showed that SM in atrial and ventricular myocytes remodel following their unique programs. ICM affected 63 genes in ventricular myocytes and 12 genes in atrial myocytes. Only few of the identified genes were previously linked to human cardiac disfunctions.
Project description:We wanted to see whether the set of affected genes in ischemic cardiomyopathy (ICM) is the same or different as compared to dilated cardiomyopathy (DCM). To find this out, we placed the single DCM sample on the same microarray slide with the ICM samples. Analysis of microarray data with ICM samples only showed 63 affected genes, while that carried out with 2 ICM samples PLUS one DCM sample reduced this number to just four genes. From this result we conclude that ICM and DCM affect different sets of genes in ventricular myocytes. Keywords: Expression profiling by array From the associated publication: To find out whether the splice microarray results reported in Table 3 are disease-type specific, we supplemented the same splice microarray of ICM ventricular myocytes with one additional sample prepared from left ventricle of a 41-years old dilated cardiomyopathy male donor. The top-list ANOVA gene score annotation for combined altered CE&P genes in ventricular myocytes (Table 3) was reduced from 63 to just 4 genes (FXYD1 (Gfold = +2.4), HCN2 (-1.5), GLRA1 (-1.8) and GJC1 (-2.3)).
Project description:Lamin A/C proteins, encoded by the LMNA gene, are intermediate filament proteins of the nuclear lamina, and predominantly expressed in differentiated cells including cardiomyocytes. Mutations in LMNA are associated with laminopathies, congenital diseases affecting muscle and homeostasis. One of the laminopathies associated with a missense mutation (N195K) in the A-type lamins results in dilated cardiomyopathy (DCM) with arrhythmias and sudden death. However it is unknown how the mutation in this LMNA gene contributes to the mechanism of arrhythmia and sudden death. To investigate this a mouse line expressing the Lmna-N195K (LmnaN195K/N195K) was used. Mutant mice demonstrated reduced fractional shortening, LV mass, wall thickness and dilated cardiomyopathy by echocardiography at 6 weeks consistent with human DCM, and died at an early age (6-7 weeks). Comparative cDNA microarray analysis from LmnaN195K/N195K and the wild type (WT) control ventricles at 6 weeks age revealed significant alterations in the expression of ion channels, transporter proteins, caveolins and associated proteins such as MAP kinases. Transmission electron microscopy analysis showed structural alterations of the ventricular myocytes with increase in number of caveolae. Quantitative Western blot analysis confirmed reduced expression for Cavβ (2 fold) subunits of the L-type Ca2+ channel. In contrast the expression levels of Cav3 (2.5 fold) was significantly increased. To investigate the functional impact of Lmna N195K on the ICa,L, we transiently expressed either the WT LMNA+GFP, Lmna N195K+GFP or GFP (control) in isolated neonatal mouse ventricular myocytes and performed whole cell patch clamp analysis. Transient expression of Lmna N195K significantly reduced (58 %) peak ICa,L (-6.0 ± 2 pA/pF, n=9) compared to GFP control (-14 ± 2 pA/pF, n=8). Expression of WT LMNA did not affect the ICa,L (-14.2 ± 2.5 pA/pF, n=8) compared to control. Conclusion: We conclude that Lmna N195K mutation results in reduced expression of ion channels and scaffolding proteins in the left ventricle with a significant reduction in peak ICa,L in ventricular myocytes and these may contribute to the mechanism of arrhythmia and dilated cardiomyopathy. 6 samples
Project description:Lamin A/C proteins, encoded by the LMNA gene, are intermediate filament proteins of the nuclear lamina, and predominantly expressed in differentiated cells including cardiomyocytes. Mutations in LMNA are associated with laminopathies, congenital diseases affecting muscle and homeostasis. One of the laminopathies associated with a missense mutation (N195K) in the A-type lamins results in dilated cardiomyopathy (DCM) with arrhythmias and sudden death. However it is unknown how the mutation in this LMNA gene contributes to the mechanism of arrhythmia and sudden death. To investigate this a mouse line expressing the Lmna-N195K (LmnaN195K/N195K) was used. Mutant mice demonstrated reduced fractional shortening, LV mass, wall thickness and dilated cardiomyopathy by echocardiography at 6 weeks consistent with human DCM, and died at an early age (6-7 weeks). Comparative cDNA microarray analysis from LmnaN195K/N195K and the wild type (WT) control ventricles at 6 weeks age revealed significant alterations in the expression of ion channels, transporter proteins, caveolins and associated proteins such as MAP kinases. Transmission electron microscopy analysis showed structural alterations of the ventricular myocytes with increase in number of caveolae. Quantitative Western blot analysis confirmed reduced expression for Cavβ (2 fold) subunits of the L-type Ca2+ channel. In contrast the expression levels of Cav3 (2.5 fold) was significantly increased. To investigate the functional impact of Lmna N195K on the ICa,L, we transiently expressed either the WT LMNA+GFP, Lmna N195K+GFP or GFP (control) in isolated neonatal mouse ventricular myocytes and performed whole cell patch clamp analysis. Transient expression of Lmna N195K significantly reduced (58 %) peak ICa,L (-6.0 ± 2 pA/pF, n=9) compared to GFP control (-14 ± 2 pA/pF, n=8). Expression of WT LMNA did not affect the ICa,L (-14.2 ± 2.5 pA/pF, n=8) compared to control. Conclusion: We conclude that Lmna N195K mutation results in reduced expression of ion channels and scaffolding proteins in the left ventricle with a significant reduction in peak ICa,L in ventricular myocytes and these may contribute to the mechanism of arrhythmia and dilated cardiomyopathy.
Project description:Using Multiome and previously published sc/snRNA-seq data, we studied eight anatomical regions of the human heart including left and right ventricular free walls (LV and RV), left and right atria (LA and RA), left ventricular apex (AX), interventricular septum (SP), sino-atrial node (SAN) and atrioventricular node (AVN). For the first time, we profile the cells of the human cardiac conduction system, revealing their distinctive repertoire of ion channels, G-protein coupled receptors and cell-cell interactions. We map the identified cells to spatial transcriptomic data to discover cellular niches within the eight regions of the heart.
Project description:Using Multiome and previously published sc/snRNA-seq data, we studied eight anatomical regions of the human heart including left and right ventricular free walls (LV and RV), left and right atria (LA and RA), left ventricular apex (AX), interventricular septum (SP), sino-atrial node (SAN) and atrioventricular node (AVN). For the first time, we profile the cells of the human cardiac conduction system, revealing their distinctive repertoire of ion channels, G-protein coupled receptors and cell-cell interactions. We map the identified cells to spatial transcriptomic data to discover cellular niches within the eight regions of the heart.
Project description:Using Multiome and previously published sc/snRNA-seq data, we studied eight anatomical regions of the human heart including left and right ventricular free walls (LV and RV), left and right atria (LA and RA), left ventricular apex (AX), interventricular septum (SP), sino-atrial node (SAN) and atrioventricular node (AVN). For the first time, we profile the cells of the human cardiac conduction system, revealing their distinctive repertoire of ion channels, G-protein coupled receptors and cell-cell interactions. We map the identified cells to spatial transcriptomic data to discover cellular niches within the eight regions of the heart.
Project description:The microtubule (MT) cytoskeleton can provide a mechanical resistance that can impede the motion of contracting cardiomyocytes. Yet a role of the MT network in human heart failure is unexplored. Here we utilize mass spectrometry to characterize changes to the cytoskeleton in human heart failure. Proteomic analysis of left ventricle tissue reveals a consistent upregulation and stabilization of intermediate filaments and MTs in human heart failure. This dataset includes left ventricular (LV) myocardium from 34 human hearts – either non-failing (NF) or failing hearts. NF hearts are subdivided into normal or compensated hypertrophy (cHyp), while failing hearts are subdivided into ischemic cardiomyopathy (ICM), dilated cardiomyopathy (DCM), and hypertrophic cardiomyopathy with preserved or reduced ejection fraction (HCMpEF and HCMrEF, respectively). Further details on patient classification and in vivo parameters on each heart are listed in sample details.txt.