A personalized mRNA signature for predicting hypertrophic cardiomyopathy applying machine learning methods.

Hypertrophic cardiomyopathy (HCM) may lead to cardiac dysfunction and sudden death. This study was designed to develop a HCM signature applying bioinformatics and machine learning methods. Data of HCM and normal tissues were obtained from public databases to screen differentially expressed genes (DEGs) using the R software limma package. The Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) were performed for enrichment analysis of HCM-associated DEGs. Hub genes for HCM were determined using weighted gene co-expression network analysis (WGCNA) together with two machine learning algorithms (SVM-RFE and LASSO). Finally, we introduced a zebrafish model to simulate changes in the hub genes in the HCM and to observe their effects on cardiac disease development. The mRNA expression data from a total of 106 HCM tissues and 39 normal samples were collected and we screened 157 DEGs. Enrichment analysis showed that immune pathways played an important role in the pathogenesis of HCM. Three hub genes (FCN3, MYH6 and RASD1) were identified using WGCNA, SVM-RFE, and LASSO analysis. In a zebrafish model, knockdown of MYH6 and RASD1 resulted in cardiac malformations with reduced ventricular capacity and heart rate, which validated the clinical significance of these genes in the diagnosis of HCM. Based on machine learning algorithms, our study created a signature with potential impact on cardiac function and cardiac quality index for HCM. The current findings had important implications for the early diagnosis and treatment of HCM.

Expression Levels of the Tnni3k Gene in the Heart Are Highly Associated with Cardiac and Glucose Metabolism-Related Phenotypes and Functional Pathways.

BACKGROUND: Troponin-I interacting kinase encoded by the TNNI3K gene is expressed in nuclei and Z-discs of cardiomyocytes. Mutations in TNNI3K were identified in patients with cardiac conduction diseases, arrhythmias, and cardiomyopathy. METHODS: We performed cardiac gene expression, whole genome sequencing (WGS), and cardiac function analysis in 40 strains of BXD recombinant inbred mice derived from C57BL/6J (B6) and DBA/2J (D2) strains. Expression quantitative trait loci (eQTLs) mapping and gene enrichment analysis was performed, followed by validation of candidate Tnni3k-regulatory genes. RESULTS: WGS identified compound splicing and missense T659I Tnni3k variants in the D2 parent and some BXD strains (D allele) and these strains had significantly lower Tnni3k expression than those carrying wild-type Tnni3k (B allele). Expression levels of Tnni3k significantly correlated with multiple cardiac (heart rate, wall thickness, PR duration, and T amplitude) and metabolic (glucose levels and insulin resistance) phenotypes in BXDs. A significant cis-eQTL on chromosome 3 was identified for the regulation of Tnni3k expression. Furthermore, Tnni3k-correlated genes were primarily involved in cardiac and glucose metabolism-related functions and pathways. Genes Nodal, Gnas, Nfkb1, Bmpr2, Bmp7, Smad7, Acvr1b, Acvr2b, Chrd, Tgfb3, Irs1, and Ppp1cb were differentially expressed between the B and D alleles. CONCLUSIONS: Compound splicing and T659I Tnni3k variants reduce cardiac Tnni3k expression and Tnni3k levels are associated with cardiac and glucose metabolism-related phenotypes.

1,6-Hexanediol regulates angiogenesis via suppression of cyclin A1-mediated endothelial function.

BACKGROUND: Angiogenesis plays important roles in physiological and pathologic conditions, but the mechanisms underlying this complex process often remain to be elucidated. In recent years, liquid-liquid phase separation (LLPS) has emerged as a new concept to explain many cellular functions and diseases. However, whether LLPS is involved in angiogenesis has not been studied until now. Here, we investigated the potential role of LLPS in angiogenesis and endothelial function. RESULTS: We found 1,6-hexanediol (1,6-HD), an inhibitor of LLPS, but not 2,5-hexanediol (2,5-HD) dramatically decreases neovascularization of Matrigel plug and angiogenesis response of murine corneal in vivo. Moreover, 1,6-HD but not 2,5-HD inhibits microvessel outgrowth of aortic ring and endothelial network formation. The endothelial function of migration, proliferation, and cell growth is suppressed by 1,6-HD. Global transcriptional analysis by RNA-sequencing reveals that 1,6-HD specifically blocks cell cycle and downregulates cell cycle-related genes including cyclin A1. Further experimental data show that 1,6-HD treatment greatly reduces the expression of cyclin A1 but with minimal effect on cyclin D1, cyclin E1, CDK2, and CDK4. The inhibitory effect of 1,6-HD on cyclin A1 is mainly through transcriptional regulation because proteasome inhibitors fail to rescue its expression. Furthermore, overexpression of cyclin A1 in HUVECs largely rescues the dysregulated tube formation upon 1,6-HD treatment. CONCLUSIONS: Our data reveal a critical role of LLPS inhibitor 1,6-HD in angiogenesis and endothelial function, which specifically affects endothelial G1/S transition through transcriptional suppression of CCNA1, implying LLPS as a possible novel player to modulate angiogenesis, and thus, it might represent an interesting therapeutic target to be investigated in clinic angiogenesis-related diseases in future.

AKT-mTOR signaling-mediated rescue of PRKAG2 R302Q mutant-induced familial hypertrophic cardiomyopathy by treatment with ß-adrenergic receptor (ß-AR) blocker metoprolol.

Background: Protein kinase AMP-activated non-catalytic subunit gamma 2 gene (PRKAG2) cardiac syndrome, caused by mutations in PRKAG2, often shows myocardial hypertrophy and abnormal glycogen deposition in cardiomyocytes. However, it remains incurable due to a lack of a management guideline for treatment. Methods: We constructed a fluorescently labeled adenovirus carrying the wild-type or R302Q mutant of the PRKAG2 gene, infected neonatal rat cardiomyocytes (NRCMs) and H9C2 cell lines, and then analyzed changes in AMP-activated protein kinase (AMPK) activity, cell hypertrophy, glycogen storage, and cell proliferation when presence or absence of metoprolol or protein kinase A (PKA) inhibition H89, and then analyzed the changes in AKT-mTOR signal transduction activity. Results: Overexpression of PRKAG2 R302Q in primary cardiomyocytes increased the activity of AMPK, induced cellular hypertrophy and glycogen storage, and promoted the phosphorylation levels of AKT-mTOR signaling pathway. Application of either ß1-adrenergic receptor (ß1-AR) blocker metoprolol or PKA inhibitor H89 to the cardiomyocytes rescued the hypertrophic cardiomyopathy (HCM)-like phenotypes induced by PRKAG2 R302Q, including suppression of both AKT-mTOR phosphorylation and AMPK activity. Conclusions: The current study not only determined the mechanism regulating HCM induced by PRKAG2 R302Q mutant, but also demonstrated a therapeutic strategy using ß1-AR blocker to treat the patients with PRKAG2 cardiac syndrome.

Diagnostic potential of a circulating miRNA model associated with therapeutic effect in heart failure.

Heart failure (HF), as the leading cause of death, is continuing to increase along with the aging of the general population all over the world. Identification of diagnostic biomarkers for early detection of HF is considered as the most effective way to reduce the risk and mortality. Herein, we collected plasma samples from HF patients (n = 40) before and after medical therapy to determine the change of circulating miRNAs through a quantitative real-time PCR (QRT-PCR)-based miRNA screening analysis. miR-30a-5p and miR-654-5p were identified as the most significantly changed miRNAs in the plasma of patients upon treatment. In consistence, miR-30a-5p showed upregulation and miR-654-5p showed downregulation in the circulation of 30 HF patients, compared to 15 normal controls in the training phase, from which a two-circulating miRNA model was developed for HF diagnosis. Next, we performed the model validation using an independent cohort including 50 HF patients and 30 controls. As high as 98.75% of sensitivity and 95.00% of specificity were achieved. A comparison between the miRNA model and NT-pro BNP in diagnostic accuracy of HF indicated an upward trend of the miRNA model. Moreover, change of the two miRNAs was further verified in association with the therapeutic effect of HF patients, in which miR-30a-5p showed decrease while miR-654-5p showed increase in the plasma of patients after LVAD implantation. In conclusion, the current study not only identified circulating miR-654-5p for the first time as a novel biomarker of HF, but also developed a novel 2-circulating miRNA model with promising potentials for diagnosis and prognosis of HF patients, and in association with therapeutic effects as well.

Tanyu Tongzhi Formula Delays Atherosclerotic Plaque Progression by Promoting Alternative Macrophage Activation via PPARγ and AKT/ERK Signal Pathway in ApoE Knock-Out Mice.

We previously demonstrated that the Tanyu Tongzhi Formula (TTF) significantly alleviated the clinical symptoms of patients with coronary heart disease and lowered serum lipid and inflammatory factor levels in patients with coronary heart disease and atherosclerosis model rats. However, the mechanism underlying TTF remains unknown. In this study, we examined the effect of TTF on atherosclerotic plaques in ApoE-/- mice and underlying mechanisms involved in macrophage polarization. Sixty male ApoE-/- mice were randomly divided into four groups. Mice in the control group were fed a regular diet, whereas experimental mice were fed a high-fat diet and received either saline (HFD group) or TTF at concentrations of 0.60 (TTF-L group) or 2.25 g/ml (TTF-H group) by daily oral gavage for 16 weeks. In the TTF-L and TTF-H groups, the levels of serum cholesterol, triglyceride, interleukin (IL)-1ß, IL-6, and tumor necrosis factor (TNF)-α were decreased, lipid content was significantly decreased, and percentage area of collagen/lipid increased in atherosclerotic plaque compared to in the HFD group. Moreover, we found TTF promoted the expression of alternative macrophage markers (Fizz1, Arg1, and Mrc) and suppressed the expression of M1 macrophage markers (TNF-α, IL-1ß, and IL-6) by regulating peroxisome proliferator-activated receptor γ (PPARγ) expression and AKT/extracellular signal-regulated kinase (ERK) activation. We further investigated whether alternative macrophage was reduced when PPARγ was inhibited or the AKT/ERK signaling pathway was activated. TTF delayed atherosclerotic plaque progression by promoting alternative macrophage activation through increasing PPARγ expression and inhibiting AKT/ERK phosphorylation, providing a theoretical basis for its clinical application.

Specific protein 1 inhibitor mithramycin A protects cardiomyocytes from myocardial infarction via interacting with PARP.

Specific protein 1 (SP1) might act as a critical transcription regulator in myocardial infarction (MI), but little evidence about its function in regulating cardiac apoptosis, a major cause of MI development, has been revealed. This study tried to investigate the role of SP1 in MI and its interaction with poly-ADP-ribose polymerase (PARP)-1 by using SP1 inhibitor, mithramycin A (mithA). Primary mouse cardiomyocytes and commercial mouse cardiomyocytes were subjected to mithA treatment under hypoxia conditions, while cell viability, Nix promoter activity, and its expression were detected correspondingly. PARP overexpression and knockdown were conducted, respectively, in mithA-treated and SP1-overexpressing cells. Co-immunoprecipitation was used to verify the interaction between PARP and SP1. For in vivo experiments, mithA administration was performed after the injections of adenovirus for PARP overexpression, and then, MI introduction was carried out. Infarct size and lactate dehydrogenase level were measured to assess MI injury. SP1 inhibitor mithA attenuated hypoxia-induced decrease of cell viability and Nix transcriptional activation, which could be inhibited by PARP overexpression. Knockdown of PARP prevented SP1-induced transcription of Nix and cell viability change, and PARP showed direct interaction with SP1. Furthermore, mithA administration reduced MI injuries, while PARP overexpression could suppress the improvement. The cardioprotective role of SP1 inhibitor mithA was demonstrated here expanding the role of SP1 in MI development involving hypoxia-induced cardiac apoptosis. Moreover, PARP acted as a transcriptional coactivator in Nix transcription involving its interaction with SP1.

Knockout of the Prostaglandin E2 Receptor Subtype 3 Promotes Eccentric Cardiac Hypertrophy and Fibrosis in Mice.

BACKGROUND:: Prostaglandin E2 receptor subtype 3 (EP3), a Gi protein-coupled receptor activated by prostaglandin E2, plays a particular role in cardioprotection. This study aimed to investigate the impact of EP3 deletion on cardiac remodeling and further elucidate the related involvement of possible signaling pathways. METHODS AND RESULTS:: The animals used were EP3 receptor knockout (EP3KO) mice and wild-type (WT) litter mate controls at 16-18 weeks old. The high-resolution echocardiography and weight index indicated that eccentric cardiac hypertrophy might occur in EP3KO mice, which were having worse cardiac function than WT litter mates. Isolated adult myocytes from EP3KO hearts showed spontaneous lengthening. Cardiac fibrosis was observed in EP3KO mice through Masson trichrome staining. The elevated messenger RNA (mRNA) level in matrix genes and the reduced mRNA, protein, and activity levels of matrix metalloproteinase 2 (MMP-2) indicated an increased synthesis and suppressed degradation of matrix collagen in EP3KO mice. The phosphorylation level of extracellular signal-regulated kinase (ERK) 1/2 protein was reduced in the cardiac tissue of EP3KO mice, accompanied by no significant change in the protein level of total ERK1/2, total p38, phospho-p38, glycogen synthase kinase-3ß (GSK3ß), phospho-GSK3ß, and calcineurin (CaN) as well as CaN activity. CONCLUSION:: EP3 knockout in cardiac tissues could induce eccentric cardiac hypertrophy and cardiac fibrosis at 16-18 weeks old. These effects of EP3 knockout might be regulated through inactivating MAPK/ERK pathway and affecting the MMP-2 expression. Overall, PGE2-EP3 is necessary to maintain the normal growth and development of the heart.

Dyrk1A-ASF-CaMKIIδ Signaling Is Involved in Valsartan Inhibition of Cardiac Hypertrophy in Renovascular Hypertensive Rats.

OBJECTIVES: It is known that the expression, activity and alternative splicing of Ca2+/calmodulin-dependent protein kinase IIδ (CaMKIIδ) are dysregulated in the cardiac remodeling process. Recently, we found a further signaling pathway, by which dual-specificity tyrosine phosphorylation-regulated kinase 1A (Dyrk1A) regulates the alternative splicing of CaMKIIδ via the alternative splicing factor (ASF), i.e., Dyrk1A-ASF-CaMKIIδ. In this study, we aimed to investigate whether Dyrk1A-ASF-CaMKIIδ signaling was involved in valsartan inhibition of cardiac hypertrophy in renovascular hypertensive rats. METHODS: Rats were subjected to two kidney-one clip (2K1C) surgery and then treated with valsartan (30 mg/kg/day) for 8 weeks. Hypertrophic parameter analysis was then performed. Western blot analysis was used to determine the protein expression of Dyrk1A and ASF and RT-PCR was used to analyze the alternative splicing of CaMKIIδ in the left ventricular (LV) sample. RESULTS: Valsartan attenuated cardiac hypertrophy in 2K1C rats but without impairment of cardiac systolic function. Increased protein expression of Dyrk1A and decreased protein expression of ASF were observed in the LV sample of 2K1C rats. Treatment of 2K1C rats with valsartan reversed the changes in Dyrk1A and ASF expression in the LV sample. Valsartan adjusted the 2K1C-induced imbalance in alternative splicing of CaMKIIδ by upregulating the mRNA expression of CaMKIIδC and downregulating the mRNA expression of CaMKIIδA and CaMKIIδB. CONCLUSIONS: Valsartan inhibition of cardiac hypertrophy in renovascular hypertensive rats was mediated, at least partly, by Dyrk1A-ASF-CaMKIIδ signaling.

In-hospital clinical outcomes of elderly patients (≥60 years) undergoing primary percutaneous coronary intervention.

Elderly patients are at high risk of mortality when they present with ST-elevation myocardial infarction (STEMI). However, the clinical outcomes of this sub-group undergoing primary percutaneous coronary intervention (PPCI) have not been well established, despite recent advances in both devices and techniques. In the present retrospective cohort study from a Chinese single center, we assessed the clinical outcomes and predictors of mortality in elderly patients (≥60 years) underwent with PPCI. The primary endpoints were immediate angiographic success and in-hospital procedural success. The secondary endpoints were all-cause death in hospital. Between January 2011 and December 2013, a total of 184 consecutive patients with acute STEMI underwent PPCI were enrolled. 116 (63.04%) patients were in the elderly group. Despite the difference in lesion complexity between groups, the immediate angiographic success rate was similar (93.97% in the elderly group, and 94.12% in the non-elderly group, P=0.966). The procedural success rate were not significantly different between the two groups (90.52% in the elderly group, and 94.12% in the non-elderly group, P=0.389). However, in-hospital mortality was statistically higher in elderly group than in the non-elderly group (8.62% Vs 1.47%, P=0.048). The major causes of death were cardiac shock and malignant arrhythmias (ventricular tachycardia and fibrillation). Our results indicate that PPCI in the elderly is feasible and has a high likelihood of immediate angiographic and procedural success.

P-selectin gene polymorphism associates with pulmonary hypertension in congenital heart disease.

OBJECTIVE: To investigate the relationship between P-selectin gene polymorphism and congenital heart disease (CHD) with pulmonary hypertension (PAH). METHODS: 58 CHD patients with PAH (PAH-CHD), 43 CHD patients without PAH and 205 healthy subjects were included in this study. The concentration of plasma P-selectin was determined by ELISA kits; the direct sequencing of PCR products was used to analyze the P-selectin genotypes. RESULTS: The concentration of plasma P-selectin was markedly higher in PAH-CHD patients than that in CHD subjects and controls, while no difference was observed between CHD group and control. A significant difference of P-selectin genotype -825T/C polymorphism was observed between patients with PAH-CHD and healthy subjects (P<0.05). Logistic analysis showed that the subjects with haplotypes A-G and G-G had lower risk of PAH-CHD compared with the ones with haplotype A-A (OR=0.47, 95% CI=0.24-0.92). In the subjects of PAH-CHD and control, plasma P-selectin concentration was higher in subjects with -825TT genotype than the ones with haplotypes T-C and C-C (P<0.05). CONCLUSION: P-selectin probably involves in the development of PAH-CHD. The polymorphism of -825T/C is associated with the risk of PAH-CHD, and may be one of its risk factors.

Involvement of the dual-specificity tyrosine phosphorylation-regulated kinase 1A-alternative splicing factor-calcium/calmodulin-dependent protein kinase IIδ signaling pathway in myocardial infarction-induced heart failure of rats.

BACKGROUND: Alternative splicing factor (ASF)-regulated alternative splicing of calcium/calmodulin-dependent protein kinase IIδ (CaMKIIδ) plays an important role in pathologic cardiac remodeling. ASF can be phosphorylated by dual-specificity tyrosine phosphorylation-regulated kinase 1A (Dyrk1A). This study aimed to investigate the possible involvement of the Dyrk1A-ASF-CaMKIIδ signaling pathway in the progression of myocardial infarction (MI)-induced heart failure (HF). METHODS AND RESULTS: MI in rats was induced by means of left anterior descending coronary artery ligation. Seven weeks after MI, the increase in left ventricular internal diameter at end-diastole (LVIDd), and the decrease in both ejection fraction (EF) and fractional shortening (FS) indicated that MI rats had developed HF. Quantitative real time reverse-transcription polymerase chain reaction indicated the dysregulation of CaMKIIδ alternative splicing, ie, up-regulation of CaMKIIδA and CaMKIIδC and down-regulation of CaMKIIδB in the hearts of HF rats. Electrophoresis and immunostaining revealed that HF activated the phosphorylation of ASF and affected its subcellular localization. Western blot analysis demonstrated a significant elevation in the activity and expression of Dyrk1A in HF rats. Inversely, treatment of MI-induced HF rats with Dyrk1A inhibitor, either harmine or EGCG, improved the symptoms of HF, reversed the molecular changes of Dyrk1A and ASF, and regulated alternative splicing of CaMKIIδ in HF rats. CONCLUSIONS: Enhanced activation of Dyrk1A-ASF-CaMKIIδ signaling pathway may underlie the mechanisms of HF after MI, and Dyrk1A inhibition may contribute to inactivation of this pathway and thereby retard the progression of MI-induced HF.

Cell-Free circulating DNA: a new biomarker for the acute coronary syndrome.

BACKGROUND: In recent studies, concentrations of cell-free circulating DNA (cf-DNA) have been correlated with clinical characteristics and prognosis in several diseases. The relationship between cf-DNA concentrations and the acute coronary syndrome (ACS) remains unknown. Moreover, no data are available for the detection cf-DNA in ACS by a branched DNA (bDNA)-based Alu assay. The aim of the present study was to investigate cf-DNA concentrations in ACS and their relationship with clinical features. METHODS: Plasma cf-DNA concentrations of 137 ACS patients at diagnosis, of 60 healthy individuals and of 13 patients with stable angina (SA) were determined using a bDNA-based Alu assay. RESULTS: ACS patients (median 2,285.0, interquartile range 916.4-4,857.3 ng/ml), especially in ST-segment elevation myocardial infarction patients (median 5,745.4, interquartile range 4,013.5-8,643.9 ng/ml), showed a significant increase in plasma cf-DNA concentrations compared with controls (healthy controls: median 118.3, interquartile range 81.1-221.1 ng/ml; SA patients: median 202.3, interquartile range 112.7-256.1 ng/ml) using a bDNA-based Alu assay. Moreover, we found positive correlations between cf-DNA and Gensini scoring and GRACE (Global Registry of Acute Coronary Events) scoring in ACS. CONCLUSION: cf-DNA may be a valuable marker for diagnosing and predicting the severity of coronary artery lesions and risk stratification in ACS.

[Metoprolol attenuates pressure overload-induced myocardial hypertrophy through modulating Dryk1A-ASF-CaMKIIδ signaling pathways].

OBJECTIVE: Previous study showed that the signaling pathway of dual-specificity tyrosine-phosphorylated and regulated kinase 1A (Dyrk1A)-alternative splicing factor (ASF)- alternative splicing of Ca(2+)/calmodulin-dependent protein kinase IIδ (CaMKIIδ) is related to myocardial hypertrophy. The aim of present study was to determine the effect and related mechamism of metoprolol on pressure overload induced myocardial hypertrophy. METHODS: Pressure overload-induced hypertension was induced by coarctation of suprarenal abdominal aorta in rats. Rats were randomly divided into sham-operated control, hypertension and hypertension plus metoprolol (30 mg×kg(-1)×d(-1)) groups (n = 10 each). Blood pressure, the left ventricular weight to body weight ratio and cardiomyocytes area were measured, the protein expression of Dyrk1A and ASF were determined by Western blot and mRNA expression of alternative splicing of CaMKIIδ was detected by RT-PCR. RESULTS: Four weeks after coarctation, cardiac hypertrophy was evidenced in rats of hypertensive group, and the protein expression of Dyrk1A was significantly upregulated, while the expression of ASF was significantly downregulated, the mRNA expression of CaMKIIδ A and B were significantly upregulated and mRNA expression of CaMKIIδ C was significantly downregulated compared to those in sham-operated control rats (all P < 0.05). Treatment with metoprolol effectively attenuated cardiac hypertrophy and reversed pressure overload induced changes on Dyrk1A and ASF, and alternative splicing of CaMKIIδ (all P < 0.05). CONCLUSION: Metoprolol attenuates pressure overload-induced cardiac hypertrophy possibly through modulating Dryk1A-ASF-CaMKIIδ signaling pathways.

[Role of valsartan on myocardial Calpain I, calcineurin and Ca/calmodulin-dependent protein kinase IIδ expression of renovascular hypertensive rats].

OBJECTIVE: To determine the protein expression of Calpain I, mRNA and protein expressions and activity of calcineurin, and the alternative splicing of Ca/calmodulin-dependent protein kinase II (CaMKII) δ in the hypertrophic heart, and to investigate the effect of angiotensin II type 1 receptor blocker valsartan (Val) on cardiac hypertrophy and the level of Calpain I, calcineurin and CaMKIIδ in renovascular hypertensive rats model. METHODS: Rats were randomly divided into sham-operated control (n=8), hypertension (n=8) and hypertension plus Val (n=8, 30 mg×kg(-1)×(-1)). The renovascular hypertension was induced by two kidney-one clip methods in rats. The ratio of left ventricular weight to body weight was measured, the mRNA expression of calcineurin and alternative splicing of CaMKIIδ were determined by RT-PCR, the protein expression of Calpain I and calcineurin were measured by Western blot and the activity of calcineurin activity was assayed by a specialized kit. RESULTS: Eight weeks after procedure, hypertension rats developed significantly cardiac hypertrophy, and the protein expression of Calpain I, mRNA and protein expression and the activity of calcineurin were significantly increased compared sham-operated control rats (all P<0.01), the mRNA expression of CaMKIIδA and B increased, CaMKIIδC mRNA decreased (P<0.01). Treatment with valsartan effectively attenuated cardiac hypertrophy and reversed hypertension induced changes on myocardial Calpain I, calcineurin and CaMKIIδ. CONCLUSION: Valsartan attenuates cardiac hypertrophy in renovascular hypertensive rats, possibly through inhibiting Calpain I, calcineurin and CaMKIIδ signaling pathways.

Cyclic AMP-dependent protein kinase A regulates the alternative splicing of CaMKIIδ.

Ca(2+)/calmodulin-dependent protein kinase (CaMK) IIδ is predominantly expressed in the heart. There are three isoforms of CaMKIIδ resulting from the alternative splicing of exons 14, 15, and 16 of its pre-mRNA, which is regulated by the splicing factor SF2/ASF. Inclusion of exons 15 and 16 or of exon 14 generates δA or δB isoform. The exclusion of all three exons gives rise to δC isoform, which is selectively increased in pressure-overload-induced hypertrophy. Overexpression of either δB or δC induces hypertrophy and heart failure, suggesting their specific role in the pathogenesis of hypertrophy and heart failure. It is well known that the ß-adrenergic-cyclic AMP-dependent protein kinase A (PKA) pathway is implicated in heart failure. To determine the role of PKA in the alternative splicing of CaMKIIδ, we constructed mini-CaMKIIδ genes and used these genes to investigate the regulation of the alternative splicing of CaMKIIδ by PKA in cultured cells. We found that PKA promoted the exclusion of exons 14, 15, and 16 of CaMKIIδ, resulting in an increase in δC isoform. PKA interacted with and phosphorylated SF2/ASF, and enhanced SF2/ASF's activity to promote the exclusion of exons 14, 15, and 16 of CaMKIIδ, leading to a further increase in the expression of δC isoform. These findings suggest that abnormality in ß-adrenergic-PKA signaling may contribute to cardiomyopathy and heart failure through dysregulation in the alternative splicing of CaMKIIδ exons 14, 15, and 16 and up-regulation of CaMKIIδC.

[Cardiac troponin I gene mutation (Asp127Tyr) in a Chinese patient with hypertrophic cardiomyopathy].

OBJECTIVE: To observe the disease-causing gene mutation in Chinese patients with hypertrophic cardiomyopathy and to analyze the correlation between the genotype and the phenotype. METHODS: Specimens of peripheral blood were collected and the genome DNA was extracted in 65 unrelated patients with hypertrophic cardiomyopathy and 60 normal controls. The exon 7 and 8 of cardiac troponin I gene were screened with PCR and direct sequencing technique. RESULTS: A missense mutation in the exon 7 of the cardiac troponin I gene was identified in a 40-year-old male patient with hypertrophic cardiomyopathy (Asp127Tyr) which was absent in the controls. CONCLUSION: A novel missense mutation of cardiac troponin I was identified in a patient with hypertrophic cardiomyopathy, this mutation might be the disease-causing gene mutation in this Chinese patient.

Angiotensin-converting enzyme inhibitor suppresses activation of calcineurin in renovascular hypertensive rats.

Accumulating evidence suggests an important role of the calcineurin signaling pathway in mediating the development of cardiac hypertrophy. It has also been reported that angiotensin-converting enzyme inhibitors (ACEIs) regressed cardiac hypertrophy in some animal and human models. In this study, we investigated the possible role of calcineurin in the regression of cardiac hypertrophy induced by the ACEI perindopril in rats with renovascular hypertension. The effect of the calcineurin inhibitor cyclosporine A (CsA) was also studied. Starting from 2 months after a two-kidney one-clip (2K1C) procedure, the rats that had developed progressive left ventricular (LV) hypertrophy were daily administered perindopril (1 mg/kg per day) or CsA (20 mg/kg per day) until 3 months. At the end of either treatment, the LV gravimetric, morphometric and histological measurements revealed the regression of LV hypertrophy; and the enzymatic assay, Western blotting and reverse transcription-polymerase chain reaction (RT-PCR) showed that both calcineurin activity and the calcineurin protein and mRNA expression levels were significantly decreased compared with untreated 2K1C rats, but that LV systolic performance was unchanged by either treatment. These data suggest that the cardiac hypertrophy regression induced by the ACEI perindopril is likely mediated, at least in part, through inhibition of the calcineurin signaling pathway.