Global changes in gene expression during cardiac hypertrophy: A new direction of cardiac signaling research

2006 ◽  
Vol 41 (2) ◽  
pp. 219-222 ◽  
Author(s):  
Soichiro Usui ◽  
Ijen Yeh ◽  
Bin Tian ◽  
Junichi Sadoshima
2014 ◽  
Vol 115 (suppl_1) ◽  
Author(s):  
Mickey Miller ◽  
Aman Makaju ◽  
Li Wang ◽  
Sarah Franklin

While global changes in gene expression are a hallmark of cardiac hypertrophy, much less is known regarding the epigenetic factors driving these changes. Local chromatin packing and gene accessibility, which governs transcriptional status, has been correlated with specific post-translational modifications on the histone tails of nucleosomes occupying these regions. However, the specific alterations in histone post-translational modifications driving gene expression changes during cardiac hypertrophy are largely unknown. To identify myocyte specific changes in histone post-translational modifications during cardiac hypertrophy we performed label-free quantitation of nuclear proteins from isolated neonatal rat ventricular myocytes exposed to the hypertrophic agonists, phenylephrine and isoproterenol. Peptide samples were analyzed on a Thermo Orbitrap Velos Pro mass spectrometer using CID & HCD fragmentation. Differential expression analysis was performed using the Progenesis LC-MS software where modified histone peptides were normalized against total protein expression. We observed multiple known and novel post-translational modifications on each of the four core histones, many of which changed in the setting of hypertrophy. To validate these findings in an animal model we performed the same analysis of histone post-translational modifications from cardiac tissue of mice under basal conditions or after pressure-overload induced hypertrophy. This study provides the first global characterization of myocyte specific changes in histone post-translational modifications in cardiac hypertrophy and highlight basic mechanisms of genomic reprogramming operative in disease.


2012 ◽  
Vol 111 (suppl_1) ◽  
Author(s):  
Emma Monte ◽  
Kevin Mouillesseaux ◽  
Haodong Chen ◽  
Shuxun Ren ◽  
Yibin Wang ◽  
...  

Cardiac hypertrophy is a common precursor to heart failure, during which cardiomyocytes grow to compensate for an increased workload. Hypertrophic cardiomyocytes undergo significant changes in cellular plasticity by adopting the expression profile and some phenotypic aspects of more primitive (embryonic or fetal) cardiac cells. These global changes in gene expression, conserved between humans and animal models of heart failure, must be preceded by structural alterations to the chromatin. Specifically, chromatin regions must be architecturally modified to allow or deny access for transcriptional machinery. However, the proteins responsible for remodeling chromatin to accomplish these gene expression changes during cardiac hypertrophy and failure are largely unknown. We used a proteomics approach to identify proteins bound to cardiac chromatin and to quantify changes in their abundance during disease. Quantitative mass spectrometry and bioinformatics revealed that 366 of the chromatin-bound proteins detected in this study displayed altered expression in a mouse model of pressure overload cardiac hypertrophy and failure. This included the chromatin remodeling protein Nucleolin (Ncl), which exhibited increased association with chromatin in the hypertrophic heart. To examine its role in regulating cardiac morphology and function we performed morpholino based knockdown of Ncl in zebrafish embryos. Ncl knockdown promoted the expression of bmp4 (a fetal marker), inhibited normal cardiomyocyte differentiation and resulted in abnormal heart chamber formation and looping. Hearts in surviving fish exhibited functional deficits as measured by fluorescence imaging and line-scanning analysis. To investigate the actions of Ncl in the mammalian cardiomyocyte, knockdown was carried out in isolated rat ventricular myocytes using siRNA. Loss of Ncl induced heterochromatin formation (increased Histone H3 K9-trimethylation), suppressed rDNA transcription (52% decrease in pre-rRNA via qPCR) and promoted fetal gene expression (65% increase in ANF; 41% increase in β-MHC transcripts). Overall, this study identifies Ncl as a regulator of chromatin structure, cell growth via ribosome biogenesis and cellular plasticity in the cardiomyocyte.


2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Xiaoxiang Hu ◽  
Xiaolei Liu ◽  
Chen Li ◽  
Yulu Zhang ◽  
Chengyao Li ◽  
...  

Abstract Background Parasites of the genus Trichinella are the pathogenic agents of trichinellosis, which is a widespread and severe foodborne parasitic disease. Trichinella spiralis resides primarily in mammalian skeletal muscle cells. After invading the cells of the host organism, T. spiralis must elude or invalidate the host’s innate and adaptive immune responses to survive. It is necessary to characterize the pathogenesis of trichinellosis to help to prevent the occurrence and further progression of this disease. The aims of this study were to elucidate the mechanisms of nurse cell formation, pathogenesis and immune evasion of T. spiralis, to provide valuable information for further research investigating the basic cell biology of Trichinella-infected muscle cells and the interaction between T. spiralis and its host. Methods We performed transcriptome profiling by RNA sequencing to identify global changes at 1, 3, 7, 10 and 15 days post-infection (dpi) in gene expression in the diaphragm after the parasite entered and persisted within the murine myocytes; the mice were infected by intravenous injection of newborn larvae. Gene expression analysis was based on the alignment results. Differentially expressed genes (DEGs) were identified based on their expression levels in various samples, and functional annotation and enrichment analysis were performed. Results The most extensive and dynamic gene expression responses in host diaphragms were observed during early infection (1 dpi). The number of DEGs and genes annotated in the Kyoto Encyclopedia of Genes and Genomes and Gene Ontology databases decreased significantly in the infected mice compared to the uninfected mice at 3 and 7 dpi, suddenly increased sharply at 10 dpi, and then decreased to a lower level at 15 dpi, similar to that observed at 3 and 7 dpi. The massive initial reaction of the murine muscle cells to Trichinella infection steadied in the later stages of infection, with little additional changes detected for the remaining duration of the studied process. Although there were hundreds of DEGs at each time point, only 11 genes were consistently up- or downregulated at all 5 time points. Conclusions The gene expression patterns identified in this study can be employed to characterize the coordinated response of T. spiralis-infected myocytes in a time-resolved manner. This comprehensive dataset presents a distinct and sensitive picture of the interaction between host and parasite during intracellular infection, which can help to elucidate how pathogens evade host defenses and coordinate the biological functions of host cells to survive in the mammalian environment.


2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Changhe Ji ◽  
Jakob Bader ◽  
Pradhipa Ramanathan ◽  
Luisa Hennlein ◽  
Felix Meissner ◽  
...  

AbstractGene expression requires tight coordination of the molecular machineries that mediate transcription and splicing. While the interplay between transcription kinetics and spliceosome fidelity has been investigated before, less is known about mechanisms regulating the assembly of the spliceosomal machinery in response to transcription changes. Here, we report an association of the Smn complex, which mediates spliceosomal snRNP biogenesis, with the 7SK complex involved in transcriptional regulation. We found that Smn interacts with the 7SK core components Larp7 and Mepce and specifically associates with 7SK subcomplexes containing hnRNP R. The association between Smn and 7SK complexes is enhanced upon transcriptional inhibition leading to reduced production of snRNPs. Taken together, our findings reveal a functional association of Smn and 7SK complexes that is governed by global changes in transcription. Thus, in addition to its canonical nuclear role in transcriptional regulation, 7SK has cytosolic functions in fine-tuning spliceosome production according to transcriptional demand.


2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Ryosuke Nakamura ◽  
Shigeyuki Mukudai ◽  
Renjie Bing ◽  
Michael J. Garabedian ◽  
Ryan C. Branski

AbstractSimilar to the hypertrophic scar and keloids, the efficacy of glucorticoids (GC) for vocal fold injury is highly variable. We previously reported dexamethasone enhanced the pro-fibrotic effects of transforming growth factor (TGF)-β as a potential mechanism for inconsistent clinical outcomes. In the current study, we sought to determine the mechanism(s) whereby GCs influence the fibrotic response and mechanisms underlying these effects with an emphasis on TGF-β and nuclear receptor subfamily 4 group A member 1 (NR4A1) signaling. Human VF fibroblasts (HVOX) were treated with three commonly-employed GCs+ /-TGF-β1. Phosphorylation of the glucocorticoid receptor (GR:NR3C1) and activation of NR4A1 was analyzed by western blotting. Genes involved in the fibrotic response, including ACTA2, TGFBR1, and TGFBR2 were analyzed by qPCR. RNA-seq was performed to identify global changes in gene expression induced by dexamethasone. GCs enhanced phosphorylation of GR at Ser211 and TGF-β-induced ACTA2 expression. Dexamethasone upregulated TGFBR1, and TGFBR2 in the presence of TGF-β1 and increased active NR4A1. RNA-seq results confirmed numerous pathways, including TGF-β signaling, affected by dexamethasone. Synergistic pro-fibrotic effects of TGF-β were observed across GCs and appeared to be mediated, at least partially, via upregulation of TGF-β receptors. Dexamethasone exhibited diverse regulation of gene expression including NR4A1 upregulation consistent with the anti-fibrotic potential of GCs.


1996 ◽  
Vol 90 (3) ◽  
pp. 197-204 ◽  
Author(s):  
Hideo Kawakami ◽  
Hideki Okayama ◽  
Mareomi Hamada ◽  
Kunio Hiwada

1. We assessed the changes of atrial natriuretic peptide and brain natriuretic peptide gene expression associated with progression and regression of cardiac hypertrophy in renovascular hypertensive rats (RHR). 2. Two-kidney, one-clip hypertensive rats (6-week-old male Wistar) were made and studied 6 (RHR-1) and 10 weeks (RHR-2) after the procedure. Regression of cardiac hypertrophy was induced by nephrectomy at 6 weeks after constriction, and the nephrectomized rats were maintained further for 4 weeks (nephrectomized rat: NEP). Sham operation was performed, and the rats were studied after 6 (Sham-1) and 10 weeks (Sham-2). Atrial natriuretic peptide and brain natriuretic peptide gene expression in the left ventricle was analysed by Northern blotting. 3. Plasma atrial natriuretic peptide and brain natriuretic peptide were significantly higher in RHR-1 and RHR-2 than in Sham-1, Sham-2 and NEP. Atrial natriuretic peptide and brain natriuretic peptide mRNA levels in RHR-1 were approximately 7.2-fold and 1.8-fold higher than those in Sham-1, respectively, and the corresponding levels in RHR-2 were 13.0-fold and 2.4-fold higher than those in Sham-2, respectively. Atrial natriuretic peptide and brain natriuretic peptide mRNA levels of NEP were normalized. Levels of atrial natriuretic peptide and brain natriuretic peptide mRNA were well correlated positively with left ventricular weight/body weight ratios. There was a significant positive correlation between the levels of atrial natriuretic peptide and brain natriuretic peptide mRNA (r = 0.86, P<0.01). 4. We conclude that the expression of atrial natriuretic peptide and brain natriuretic peptide genes is regulated in accordance with the degree of myocardial hypertrophy and that the augmented expression of these two natriuretic peptides may play an important role in the maintenance of cardiovascular haemodynamics in renovascular hypertension.


2014 ◽  
Vol 89 (3) ◽  
pp. 1608-1627 ◽  
Author(s):  
Florian Bellutti ◽  
Maximilian Kauer ◽  
Doris Kneidinger ◽  
Thomas Lion ◽  
Reinhard Klein

ABSTRACTAdenoviruses encode a set of highly abundant microRNAs (mivaRNAs), which are generated by Dicer-mediated cleavage of the larger noncoding virus-associated RNAs (VA RNAs) I and II. We performed deep RNA sequencing to thoroughly investigate the relative abundance of individual single strands of mivaRNA isoforms in human A549 cells lytically infected with human adenovirus 5 (Ad5) at physiologically relevant multiplicities of infection (MOIs). In addition, we investigated their relative abundance in the endogenous RNA-induced silencing complexes (RISCs). The occupation of endogenous RISCs by mivaRNAs turned out to be pronounced but not as dominant as previously inferred from experiments with AGO2-overexpressing cells infected at high MOIs. In parallel, levels of RISC-incorporated mRNAs were investigated as well. Analysis of mRNAs enriched in RISCs in Ad5-infected cells revealed that only mRNAs with complementarity to the seed sequences of mivaRNAs derived from VA RNAI but not VA RNAII were overrepresented among them, indicating that only mivaRNAs derived from VA RNAI are likely to contribute substantially to the posttranscriptional downregulation of host gene expression. Furthermore, to generate a comprehensive picture of the entire transcriptome/targetome in lytically infected cells, we determined changes in cellular miRNA levels in both total RNA and RISC RNA as well, and bioinformatical analysis of mRNAs of total RNA/RISC fractions revealed a general, genome-wide trend toward detargeting of cellular mRNAs upon infection. Lastly, we identified the direct targets of both single strands of a VA RNAI-derived mivaRNA that constituted one of the two most abundant isoforms in RISCs of lytically infected A549 cells.IMPORTANCEViral and cellular miRNAs have been recognized as important players in virus-host interactions. This work provides the currently most comprehensive picture of the entire mRNA/miRNA transcriptome and of the complete RISC targetome during lytic adenovirus infection and thus represents the basis for a deeper understanding of the interplay between the virus and the cellular RNA interference machinery. Our data suggest that, at least in the model system that was employed, lytic infection by Ad5 is accompanied by a measurable global net detargeting effect on cellular mRNAs, and analysis of RISC-associated viral small RNAs revealed that the VA RNAs are the only source of virus-encoded miRNAs. Moreover, this work allows to assess the power of individual viral miRNAs to regulate cellular gene expression and provides a list of proven and putative direct targets of these miRNAs, which is of importance, given the fact that information about validated targets of adenovirus-encoded miRNAs is scarce.


2017 ◽  
Vol 121 (suppl_1) ◽  
Author(s):  
Michelle A Hardyman ◽  
Stephen J Fuller ◽  
Daniel N Meijles ◽  
Kerry A Rostron ◽  
Sam J Leonard ◽  
...  

Introduction: Raf kinases lie upstream of ERK1/2 with BRaf being the most highly expressed and having the highest basal activity. V600E BRaf mutations constitutively activate ERK1/2 and are common in cancer. The role of BRaf in the adult heart is yet to be established. ERK1/2 regulate cardiomyocyte gene expression, promoting cardiac hypertrophy and cardioprotection, but effects of ERK1/2 may depend on signal strength. Hypothesis: Our hypotheses are that BRaf is critical in regulating ERK1/2 signaling in cardiomyocytes and, whilst moderate ERK1/2 activity is beneficial, excessive ERK1/2 activity is detrimental to the heart. Methods: We generated heterozygote mice for tamoxifen- (Tam-) inducible cardiomyocyte-specific knockin of V600E in the endogenous BRaf gene. Mice (12 wks) received 2 injections of Tam or vehicle on consecutive days (n=4-10 per group). Kinase activities and mRNA expression were assessed by immunoblotting and qPCR. Echocardiography was performed (Vevo2100). M-mode images (short axis view) were analyzed; data for each mouse were normalized to the mean of 2 baseline controls. Results: V600E knockin did not affect overall BRaf or cRaf levels in mouse hearts, but significantly increased ERK1/2 activities within 48 h (1.51±0.05 fold). Concurrently, mRNAs for hypertrophic gene markers including BNP and immediate early genes (IEGs) increased signficantly. At 72 h, expression of BNP, Fosl1, Myc, Ereg and CTGF increased further, other IEGs (Jun, Fos, Egr1, Atf3) declined, and ANF was upregulated. In contrast, expression of α and β myosin heavy chain mRNAs was substantially downregulated (0.46/0.41±0.05 relative to controls). Within 72 h, left ventricular (LV) mass and diastolic LV wall thickness had increased (1.23±0.05 relative to controls), but cardiac function was severely compromised with significant decreases in ejection fraction and cardiac output (0.53/0.68±0.09 relative to controls) associated with increased LV internal diameters and cardiac volumes. Conclusions: Endogenous cardiomyocyte BRaf is sufficient to activate ERK1/2 in mouse hearts and induce cardiac hypertrophy associated with dynamic temporal changes in gene expression. However, excessive activation of ERK1/2 in isolation is detrimental to cardiac function.


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