Widespread downregulation of cardiac mitochondrial and sarcomeric genes in patients with sepsis
ABSTRACT: The mechanism(s) for septic cardiomyopathy in humans is not known. To address this, we performed transcriptional profiling of hearts from patients who died from sepsis, in comparison to non-failing human donor hearts that could not be transplanted for technical reasons. Overall design: 20 sepsis patients, 11 ischemic heart disease (IHD), 9 nonischemic dilated cardiomyopathy (DCM), 11 non-failing donors. The additional de-identified, clinical data for GSM2109161-66, GSM2109168-79 (total 18 samples) is provided in the 'Clinical_metadata.xls' (as a series supplementary file).
INSTRUMENT(S): [HuGene-1_0-st] Affymetrix Human Gene 1.0 ST Array [transcript (gene) version]
Project description:OBJECTIVES:The mechanism(s) for septic cardiomyopathy in humans is not known. To address this, we measured messenger RNA alterations in hearts from patients who died from systemic sepsis, in comparison to changed messenger RNA expression in nonfailing and failing human hearts. DESIGN:Identification of genes with altered abundance in septic cardiomyopathy, ischemic heart disease, or dilated cardiomyopathy, in comparison to nonfailing hearts. SETTING:ICUs at Barnes-Jewish Hospital, St. Louis, MO. PATIENTS:Twenty sepsis patients, 11 ischemic heart disease, nine dilated cardiomyopathy, and 11 nonfailing donors. INTERVENTIONS:None other than those performed as part of patient care. MEASUREMENTS AND MAIN RESULTS:Messenger RNA expression levels for 198 mitochondrially localized energy production components, including Krebs cycle and electron transport genes, decreased by 43% ± 5% (mean ± SD). Messenger RNAs for nine genes responsible for sarcomere contraction and excitation-contraction coupling decreased by 43% ± 4% in septic hearts. Surprisingly, the alterations in messenger RNA levels in septic cardiomyopathy were both distinct from and more profound than changes in messenger RNA levels in the hearts of patients with end-stage heart failure. CONCLUSIONS:The expression profile of messenger RNAs in the heart of septic patients reveals striking decreases in expression levels of messenger RNAs that encode proteins involved in cardiac energy production and cardiac contractility and is distinct from that observed in patients with heart failure. Although speculative, the global nature of the decreases in messenger RNA expression for genes involved in cardiac energy production and contractility suggests that these changes may represent a short-term adaptive response of the heart in response to acute change in cardiovascular homeostasis.
Project description:Myocardial hibernation (MH) is a well-known feature of human ischaemic cardiomyopathy (ICM), whereas its presence in human idiopathic dilated cardiomyopathy (DCM) is still controversial. We investigated the histological and molecular features of MH in left ventricle (LV) regions of failing DCM or ICM hearts. We examined failing hearts from DCM (n = 11; 41.9 ± 5.45 years; left ventricle-ejection fraction (LV-EF), 18 ± 3.16%) and ICM patients (n = 12; 58.08 ± 1.7 years; LVEF, 21.5 ± 6.08%) undergoing cardiac transplantation, and normal donor hearts (N, n = 8). LV inter-ventricular septum (IVS) and antero-lateral free wall (FW) were transmurally (i.e. sub-epicardial, mesocardial and sub-endocardial layers) analysed. LV glycogen content was shown to be increased in both DCM and ICM as compared with N hearts (P < 0.001), with a U-shaped transmural distribution (lower values in mesocardium). Capillary density was homogenously reduced in both DCM and ICM as compared with N (P < 0.05 versus N), with a lower decrease independent of the extent of fibrosis in sub-endocardial and sub-epicardial layers of DCM as compared with ICM. HIF1-? and nestin, recognized ischaemic molecular hallmarks, were similarly expressed in DCM-LV and ICM-LV myocardium. The proteomic profile was overlapping by ~50% in DCM and ICM groups. Morphological and molecular features of MH were detected in end-stage ICM as well as in end-stage DCM LV, despite epicardial coronary artery patency and lower fibrosis in DCM hearts. Unravelling the presence of MH in the absence of coronary stenosis may be helpful to design a novel approach in the clinical management of DCM.
Project description:Dilated cardiomyopathy (DCM) is associated with extensive pathological cardiac remodeling and involves numerous changes in the protein expression profile of the extracellular matrix of the heart. We obtained seven human, end-stage, failing hearts with DCM (DCM-failing) and nine human, nonfailing donor hearts and compared their extracellular matrix protein profiles. We first showed that the DCM-failing hearts had indeed undergone extensive remodeling of the left ventricle myocardium relative to nonfailing hearts. We then isolated the extracellular matrix from a subset of these hearts and performed a proteomic analysis on the isolated matrices. We found that the levels of 26 structural proteins were altered in the DCM-failing isolated cardiac extracellular matrix compared to nonfailing isolated cardiac extracellular matrix. Overall, most of the extracellular matrix proteins showed reduced levels in the DCM-failing hearts, while all of the contractile proteins showed increased levels. There was a mixture of increased and decreased levels of cytoskeletal and nuclear transport proteins. Using immunoprobing, we verified that collagen IV (?2 and ?6 isoforms), zyxin, and myomesin protein levels were reduced in the DCM-failing hearts. We expect that these data will add to the understanding of the pathology associated with heart failure with DCM.
Project description:Sepsis is the leading cause of death in critically ill patients. While myocardial dysfunction has been recognized as a major manifestation in severe sepsis, the underlying molecular mechanisms associated with septic cardiomyopathy remain unclear. In this study, we performed a miRNA array analysis in hearts collected from a severe septic mouse model induced by cecal ligation and puncture (CLP). Among the 19 miRNAs that were dys-regulated in CLP-mouse hearts, miR-223(3p) and miR-223*(5p) were most significantly downregulated, compared with sham-operated mouse hearts. To test whether a drop of miR-223 duplex plays any roles in sepsis-induced cardiac dysfunction and inflammation, a knockout (KO) mouse model with a deletion of the miR-223 gene locus and wild-type (WT) mice were subjected to CLP or sham surgery. We observed that sepsis-induced cardiac dysfunction, inflammatory response and mortality were remarkably aggravated in CLP-treated KO mice, compared with control WTs. Using Western-blotting and luciferase reporter assays, we identified Sema3A, an activator of cytokine storm and a neural chemorepellent for sympathetic axons, as an authentic target of miR-223* in the myocardium. In addition, we validated that miR-223 negatively regulated the expression of STAT-3 and IL-6 in mouse hearts. Furthermore, injection of Sema3A protein into WT mice revealed an exacerbation of sepsis-triggered inflammatory response and myocardial depression, compared with control IgG1 protein-treated WT mice following CLP surgery. Taken together, these data indicate that loss of miR-223/-223* causes an aggravation of sepsis-induced inflammation, myocardial dysfunction and mortality. Our study uncovers a previously unrecognized mechanism underlying septic cardiomyopathy and thereby, may provide a new strategy to treat sepsis.
Project description:Heart failure (HF) is a worldwide pandemic with an unacceptable high level of morbidity and mortality. Understanding the different pathophysiological mechanisms will contribute to prevention and individualized therapy of HF. We established mouse models for ischemic cardiomyopathy (ICM) and dilated cardiomyopathy (DCM) by inducing myocardial infarction (MI) and Coxsackievirus B3 infection, respectively. Isobaric tags for relative and absolute quantitation and liquid chromatography coupled with tandem mass spectrometry technology was used to identify the protein expression profiles in control and failing hearts. A total of 1,638 proteins were identified and compared in this proteomics analysis. Among them, 286 proteins were differently expressed. Gene ontology, KEGG pathway and ingenuity pathway analysis was performed to systematically assess the potential connections of the differentially expressed proteins to biological functions. Compared with control group, the differentially expressed proteins derived from the hearts of ICM and DCM mice were partially similar and mainly modulated in oxidative phosphorylation, metabolism and protein folding pathways. Moreover, difference still existed, the differentially expressed proteins between DCM and ICM hearts were significantly modulated in oxidative phosphorylation, metabolic and AMPK signaling pathways. Confirmatory western bolt analysis demonstrated that SDHB was down-regulated in both ICM and DCM hearts, while UQCRQ, GLUT4 and adiponectin were up-regulated in ICM hearts. Adenosine triphosphate (ATP) concentration significantly decreased in both DCM and ICM hearts. The protein expression of phospho-AMPK? decreased significantly in DCM hearts, but increased in ICM. In summary, oxidative phosphorylation, cardiac metabolism, and protein folding play critical roles in the pathogenesis of HF. The diverse changes in protein expression profiles between failing hearts induced by either MI or CVB3 infection demonstrated the heterogeneity of HF. Understanding the differences in proteome profiles could offer more precise therapeutic options for HF.
Project description:Cardiovascular disease is the leading cause of human morbidity and mortality. Dilated cardiomyopathy (DCM) is the most common form of cardiomyopathy associated with heart failure. Here, we report that cardiac-specific knockout of Dicer, a gene encoding a RNase III endonuclease essential for microRNA (miRNA) processing, leads to rapidly progressive DCM, heart failure, and postnatal lethality. Dicer mutant mice show misexpression of cardiac contractile proteins and profound sarcomere disarray. Functional analyses indicate significantly reduced heart rates and decreased fractional shortening of Dicer mutant hearts. Consistent with the role of Dicer in animal hearts, Dicer expression was decreased in end-stage human DCM and failing hearts and, most importantly, a significant increase of Dicer expression was observed in those hearts after left ventricle assist devices were inserted to improve cardiac function. Together, our studies demonstrate essential roles for Dicer in cardiac contraction and indicate that miRNAs play critical roles in normal cardiac function and under pathological conditions.
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.
Project description:Cardiomyopathy is a common myocardial disease that can lead to sudden death. However, molecular mechanisms underlying cardiomyopathy remain unclear. Jumonji and AT-rich interaction domain-containing 2 (Jarid2) is necessary for embryonic heart development, but functions of Jarid2 after birth remain to be elucidated. Here, we report that myocardial-specific deletion of Jarid2 using ?MHC::Cre mice (Jarid2 ?MHC) causes dilated cardiomyopathy (DCM) and premature death 6-9 months after birth. To determine functions of Jarid2 in the adult heart and DCM, we analyzed gene expression in the heart at postnatal day (p)10 (neonatal) and 7 months (DCM). Pathway analyses revealed that dysregulated genes in Jarid2 ?MHC hearts at p10, prior to cardiomyopathy, represented heart development and muscle contraction pathways. At 7 months, down-regulated genes in Jarid2 ?MHC hearts were enriched in metabolic process and ion channel activity pathways and up-regulated genes in extracellular matrix components. In normal hearts, expression levels of contractile genes were increased from p10 to 7 months but were not sufficiently increased in Jarid2 ?MHC hearts. Moreover, Jarid2 was also necessary to repress fetal contractile genes such as TroponinI1, slow skeletal type (Tnni1) and Actin alpha 2, smooth muscle (Acta2) in neonatal stages through ErbB2-receptor tyrosine kinase 4 (ErbB4) signaling. Interestingly, Ankyrin repeat domain 1 (Ankrd1) and Neuregulin 1 (Nrg1), whose expression levels are known to be increased in the failing heart, were already elevated in Jarid2 ?MHC hearts within 1 month of birth. Thus, we demonstrate that ablation of Jarid2 in cardiomyocytes results in DCM and suggest that Jarid2 plays important roles in cardiomyocyte maturation during neonatal stages.
Project description:Mitochondria are key players in the development and progression of heart failure (HF). Mitochondrial (mt) dysfunction leads to diminished energy production and increased cell death contributing to the progression of left ventricular failure. The fundamental mechanisms that underlie mt dysfunction in HF have not been fully elucidated.To characterize mt morphology, biogenesis, and genomic integrity in human HF, we investigated left ventricular tissue from nonfailing hearts and end-stage ischemic (ICM) or dilated (DCM) cardiomyopathic hearts. Although mt dysfunction was present in both types of cardiomyopathy, mt were smaller and increased in number in DCM compared with ICM or nonfailing hearts. mt volume density and mtDNA copy number was increased by ?2-fold (P<0.001) in DCM hearts in comparison with ICM hearts. These changes were accompanied by an increase in the expression of mtDNA-encoded genes in DCM versus no change in ICM. mtDNA repair and antioxidant genes were reduced in failing hearts, suggestive of a defective repair and protection system, which may account for the 4.1-fold increase in mtDNA deletion mutations in DCM (P<0.05 versus nonfailing hearts, P<0.05 versus ICM).In DCM, mt dysfunction is associated with mtDNA damage and deletions, which could be a consequence of mutating stress coupled with a peroxisome proliferator-activated receptor ? coactivator 1?-dependent stimulus for mt biogenesis. However, this maladaptive compensatory response contributes to additional oxidative damage. Thus, our findings support further investigations into novel mechanisms and therapeutic strategies for mt dysfunction in DCM.
Project description:The M-band is the prominent cytoskeletal structure that cross-links the myosin and titin filaments in the middle of the sarcomere. To investigate M-band alterations in heart disease, we analyzed the expression of its main components, proteins of the myomesin family, in mouse and human cardiomyopathy. Cardiac function was assessed by echocardiography and compared to the expression pattern of myomesins evaluated with RT-PCR, Western blot, and immunofluorescent analysis. Disease progression in transgenic mouse models for dilated cardiomyopathy (DCM) was accompanied by specific M-band alterations. The dominant splice isoform in the embryonic heart, EH-myomesin, was strongly up-regulated in the failing heart and correlated with a decrease in cardiac function (R = -0.86). In addition, we have analyzed the expressions of myomesins in human myocardial biopsies (N = 40) obtained from DCM patients, DCM patients supported by a left ventricular assist device (LVAD), hypertrophic cardiomyopathy (HCM) patients and controls. Quantitative RT-PCR revealed that the EH-myomesin isoform was up-regulated 41-fold (P < 0.001) in the DCM patients compared to control patients. In DCM hearts supported by a LVAD and HCM hearts, the EH-myomesin expression was comparable to controls. Immunofluorescent analyses indicate that EH-myomesin was enhanced in a cell-specific manner, leading to a higher heterogeneity of the myocytes' cytoskeleton through the myocardial wall. We suggest that the up-regulation of EH-myomesin denotes an adaptive remodeling of the sarcomere cytoskeleton in the dilated heart and might serve as a marker for DCM in mouse and human myocardium.