scholarly journals Differential Regulation of Myocardial E3 Ligases and Deubiquitinases in Ischemic Heart Failure

Life ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1430
Author(s):  
Kristin Klaeske ◽  
Maria Dix ◽  
Volker Adams ◽  
Khalil Jawad ◽  
Sandra Eifert ◽  
...  

The pathological changes of ubiquitination and deubiquitination following myocardial infarction (MI) and chronic heart failure (CHF) have been sparsely examined. We investigated the expression of muscle-specific E3 ubiquitin ligases and deubiquitinases in MI and CHF. Therefore, mice were assigned to coronary artery ligation for 3 days or 10 weeks as well as for sham operation (each n = 10). Expression of E3 ligases (MAFBX, MURF1, CHIP, ITCH, MDM2) and deubiquitinases (A20, CYLD, UCH-L1, USP14, USP19) was determined. After MI and in CHF, the mRNA expression of MURF1, CHIP and MDM2 (all p < 0.05) was decreased. Protein expression analyses revealed that ITCH expression decreased in CHF (p = 0.01), whereas MDM2 expression increased in MI (p = 0.02) and decreased in CHF (p = 0.02). Except for USP19 mRNA expression that decreased at 3 days and 10 weeks (both p < 0.01), the expression of other deubiquitinases remained unaffected after MI and CHF. The expression of myocardial E3 ligases is differentially regulated following MI, raising the question of whether an upstream regulation exists that is activated by MI for tissue protection or whether the downregulation of E3 ligases enables myocardial hypertrophy following MI.

2016 ◽  
Vol 310 (2) ◽  
pp. H262-H268 ◽  
Author(s):  
Hanne C. Gadeberg ◽  
Simon M. Bryant ◽  
Andrew F. James ◽  
Clive H. Orchard

In mammalian cardiac ventricular myocytes, Ca efflux via Na/Ca exchange (NCX) occurs predominantly at T tubules. Heart failure is associated with disrupted t-tubular structure, but its effect on t-tubular function is less clear. We therefore investigated t-tubular NCX activity in ventricular myocytes isolated from rat hearts ∼18 wk after coronary artery ligation (CAL) or corresponding sham operation (Sham). NCX current ( INCX) and l-type Ca current ( ICa) were recorded using the whole cell, voltage-clamp technique in intact and detubulated (DT) myocytes; intracellular free Ca concentration ([Ca]i) was monitored simultaneously using fluo-4. INCX was activated and measured during application of caffeine to release Ca from sarcoplasmic reticulum (SR). Whole cell INCX was not significantly different in Sham and CAL myocytes and occurred predominantly in the T tubules in Sham myocytes. CAL was associated with redistribution of INCX and ICa away from the T tubules to the cell surface and an increase in t-tubular INCX/ ICa density from 0.12 in Sham to 0.30 in CAL myocytes. The decrease in t-tubular INCX in CAL myocytes was accompanied by an increase in the fraction of Ca sequestered by SR. However, SR Ca content was not significantly different in Sham, Sham DT, and CAL myocytes but was significantly increased by DT of CAL myocytes. In Sham myocytes, there was hysteresis between INCX and [Ca]i, which was absent in DT Sham but present in CAL and DT CAL myocytes. These data suggest altered distribution of NCX in CAL myocytes.


Circulation ◽  
2020 ◽  
Vol 142 (Suppl_3) ◽  
Author(s):  
Hikaru Hagiwara ◽  
Masaya Watanabe ◽  
Yoichiro Fujioka, ◽  
Taro Koya ◽  
Motoki Nakao ◽  
...  

Background: Delayed after depolarization by calcium (Ca 2+ ) leak from sarcoplasmic reticulum (SR) via Ryanodine receptor is one of the causes of ventricular arrhythmias (VAs) in heart failure (HF). Ca 2+ uptake into mitochondria via mitochondrial calcium uniporter (MCU) is participated in Ca 2+ handling, but the relationship between VAs in HF and Ca 2+ uptake into mitochondria is unclear. Purpose: We sought to investigate whether increased Ca 2+ uptake into mitochondria via MCU reduces diastolic Ca 2+ leak and suppresses VAs in ischemic HF mice. Methods: Ten-week-old male C57BL/6J mice were divided into 2 groups; sham operation mice (Sham) or HF mice (HF) in which myocardial infarction was induced by left coronary artery ligation. After 4-6 weeks, cardiomyocyte or mitochondria were isolated respectively from the myocardium of Sham and the non-infarct myocardium of HF. Ca 2+ waves (CaWs) were measured on an epifluorescence microscopy. Calcium transients and calcium sparks were measured on a confocal microscope in linescan mode. Mitochondrial Ca 2+ uptake were measured by estimating the extra-mitochondrial Ca 2+ reduction with Fluo-5N on a spectrofluoro-photometer. VAs was induced in the Langendorff perfused hearts. Left ventricular (LV) pressure was measured using a microtip transducer catheter . Results: HF mice showed left ventricular dysfunction and increased heart and lung weights compared to Sham. Kaempferol, a MCU activator, increased mitochondrial Ca 2+ uptake in the isolated mitochondria both in Sham and HF. CaWs and Ca spark frequency in the presence of isoproterenol was attenuated by 10 μM Kaempferol. Kaempferol did not show significant changes in Ca 2+ transient amplitude, however increased the time to 50% decay significantly. The incidence of induced VAs was suppressed by Kaempferol. In vivo measurements, intravenous administration of Kaempferol (5mg/kg) did not show significant changes in hemodynamic parameters in HF mice. Conclusions: Ca 2+ uptake into mitochondria via MCU suppresses VAs in HF. Despite the adverse influence of the traditional antiarrhythmic drugs for HF condition, a novel strategy that promotes Ca 2+ uptake into mitochondria might be a potential therapeutic approach for VA treatment in HF patients.


2004 ◽  
Vol 287 (5) ◽  
pp. H2049-H2053 ◽  
Author(s):  
Eric E. Morgan ◽  
Michael D. Faulx ◽  
Tracy A. McElfresh ◽  
Theodore A. Kung ◽  
Michael S. Zawaneh ◽  
...  

The rat infarct model is widely used in heart failure research, but few echocardiographic indexes of left ventricular (LV) function are validated in this model. Accordingly, the objective of this study was to validate a 13-segment LV wall motion score index (WMSI) and the myocardial performance index (MPI) in infarcted rats. Twenty-nine male Wistar rats underwent left coronary artery ligation or sham operation and were evaluated with two-dimensional and Doppler flow echocardiography 8 wk later. After echocardiography, invasive indexes were obtained using a high-fidelity catheter. WMSI and MPI were correlated with the invasive and noninvasive measurements of LV function. WMSI and MPI significantly correlated directly with end-diastolic pressure ( r = 0.72 and 0.42 for WMSI and MPI, respectively) and the time constant of isovolumic relaxation ( r = 0.68 and 0.48) and inversely with peak rate of rise of LV pressure (+dP/d t; r = −0.68 and −0.50), peak rate of decline in LV pressure ( r = −0.57 and −0.44), LV developed pressure ( r = −0.58 and −0.42), area fractional shortening ( r = −0.85 and −0.53), and cardiac index ( r = −0.74 and −0.74). Stepwise linear regression analyses revealed that LV end-diastolic pressure, +dP/d t, area fractional shortening, and cardiac index were independent determinants of WMSI ( r = 0.994) and that cardiac index and +dP/d t were independent determinants of MPI ( r = 0.781). We conclude that the 13-segment WMSI and MPI are reproducible and correlate strongly with established echocardiographic and invasive indexes of systolic and diastolic function. These findings support the use of WMSI and MPI as indexes of global LV function in the rat infarction model of heart failure.


2017 ◽  
Vol 312 (3) ◽  
pp. H384-H391 ◽  
Author(s):  
Richard C. Bond ◽  
Simon M. Bryant ◽  
Judy J. Watson ◽  
Jules C. Hancox ◽  
Clive H. Orchard ◽  
...  

Constitutive regulation by PKA has recently been shown to contribute to L-type Ca2+current ( ICaL) at the ventricular t-tubule in heart failure. Conversely, reduction in constitutive regulation by PKA has been proposed to underlie the downregulation of atrial ICaLin heart failure. The hypothesis that downregulation of atrial ICaLin heart failure involves reduced channel phosphorylation was examined. Anesthetized adult male Wistar rats underwent surgical coronary artery ligation (CAL, N=10) or equivalent sham-operation (Sham, N=12). Left atrial myocytes were isolated ~18 wk postsurgery and whole cell currents recorded (holding potential=-80 mV). ICaLactivated by depolarizing pulses to voltages from -40 to +50 mV were normalized to cell capacitance and current density-voltage relations plotted. CAL cell capacitances were ~1.67-fold greater than Sham ( P ≤ 0.0001). Maximal ICaLconductance ( Gmax) was downregulated more than 2-fold in CAL vs. Sham myocytes ( P < 0.0001). Norepinephrine (1 μmol/l) increased Gmax>50% more effectively in CAL than in Sham so that differences in ICaLdensity were abolished. Differences between CAL and Sham Gmaxwere not abolished by calyculin A (100 nmol/l), suggesting that increased protein dephosphorylation did not account for ICaLdownregulation. Treatment with either H-89 (10 μmol/l) or AIP (5 μmol/l) had no effect on basal currents in Sham or CAL myocytes, indicating that, in contrast to ventricular myocytes, neither PKA nor CaMKII regulated basal ICaL. Expression of the L-type α1C-subunit, protein phosphatases 1 and 2A, and inhibitor-1 proteins was unchanged. In conclusion, reduction in PKA-dependent regulation did not contribute to downregulation of atrial ICaLin heart failure.NEW & NOTEWORTHY Whole cell recording of L-type Ca2+currents in atrial myocytes from rat hearts subjected to coronary artery ligation compared with those from sham-operated controls reveals marked reduction in current density in heart failure without change in channel subunit expression and associated with altered phosphorylation independent of protein kinase A.


2021 ◽  
Vol 22 ◽  
Author(s):  
Li-li Hong ◽  
Hong-Song Wang ◽  
Xiao-Yu Cheng ◽  
Sheng Zhang ◽  
Yan Zhao ◽  
...  

Background: Recently, the combination of Traditional Chinese Medicine (TCM) formulae and other drugs have been used frequently in clinical practice, while the possibility of herb-drug interaction (HDI) risk remains a challenge. Since metabolic enzymes mediate the majority of drug interactions, evaluating the effects of formulae on metabolic enzymes is instructive for the rational formulation of drug delivery plans. Objective: Herein, we are devoted to estimating the effects of Zhenwu detection (ZWD) on activities and mRNA expression of 7 cytochrome P450 (CYP450) isoenzymes in chronic heart failure (CHF) rats. Methods: The CHF rats were replicated by coronary artery ligation and were randomly divided into sham operation group, model group, ZWD low- (2.188 g/kg), middle- (4.375 g/kg), and high- (8.750 g/kg) dose groups, n=6. After 8 weeks, rats were administrated with ZWD and normal saline (NS) for four weeks. The mixed solution of 7 probe drugs (1 mL/kg) was subsequently injected into 30 rats through the caudal vein after the last administration. Pharmacokinetic parameters and mRNA expression of 7 probe drugs were measured by using UPLC-MS/MS and RT-qPCR, respectively. Results: Activities and mRNA expression of CYP1A2, CYP2B1, CYP2C6, CYP2C11, CYP3A1 were inhibited in CHF rats, and ZWD could reverse this effect except for CYP2B1. Conclusion: Overall, these findings underscore that for CHF patients, the HDI should be taken into consideration when ZWD is used on its own or combined with drugs meditated by CYP1A2 (CYP1A2 in rats), CYP2C9 (CYP2C6 in rats), CYP2C19 (CYP2C11 in rats) and CYP3A4 (CYP3A1 in rats). Furthermore, since amodiaquine, dextromethorphan and bupropion apparent volume of distribution (Vd) were proved far greater than the total volume of body fluids, we speculate that the dose adjustment and potential organotoxicity of these substrates may need further consideration.


Hypertension ◽  
2016 ◽  
Vol 68 (suppl_1) ◽  
Author(s):  
Ana Carolina M Omoto ◽  
Fábio N Gava ◽  
Mauro de Oliveira ◽  
Carlos A Silva ◽  
Rubens Fazan ◽  
...  

Myocardium infarction (MI) elicited by coronary artery ligation (CAL) is commonly used to induce chronic heart failure (HF) in rats. However, CAL shows high mortality rates. Given that ischemia-reperfusion (IR) may cause the development of HF, this approach may be useful for obtaining a model of HF with low mortality rates. Therefore, it was compared the model of CAL vs. IR in rats, evaluating the mortality and cardiac morphological and functional aspects. The IR consisted of 30 minutes of cardiac ischemia. Wistar rats were assigned into three groups: CAL: n=18; IR: n=7; SHAM (fictitious IR): n=7. After four weeks of CAL, the subjects were evaluated by echocardiography and ventriculography as well. The statistical analysis consisted of ANOVA combined with Tukey’s posthoc test (p<0.05). There were no deaths in the IR and SHAM groups, whereas in the CAL group the mortality rate was 33.33% (6 out of 18). In the CAL group echocardiography showed increased left ventricular (LV) cavity during systole (8.3 ± 1mm) and diastole (10.5 ± 1mm); decreased LV free wall during systole (1.4 ± 0.5 mm); increased left atrium/aorta (2.3 ± 0.4) ratio. These changes were not significant in IR (4.8 ± 0.5mm, 7.6 ± 0.6mm, 2.6 ± 0.3 mm, 1.6 ± 0.2) and SHAM (4.6 ± 0.6 mm, 7.7 ± 0.8mm, 2.8 ± 0.4mm, 1.5 ± 0.2) groups. There was also the reduction in the ejection fraction in the CAL group (41 ± 12 %) when compared with IR (65 ± 9%) and SHAM (69 ± 7%) groups. The tissue Doppler analysis from the lateral mitral annulus showed reduction in E′ in CAL (-29 ± 8 mm/s) and IR (-31± 9 mm/s) groups when compared with the SHAM (-48 ± 11 mm/s) group. The ventriculography in the CAL group showed smaller maximum dP/dt (6519 ± 1062) and greater end-diastolic pressure (33 ± 8 mmHg) when compared with IR (8716 ± 756 mmHg/s; 9 ± 9 mmHg) and SHAM (7989 ± 1230 mmHg/s; 9 ± 7 mmHg) groups. The CAL group presented transmural infarct size of 40% of the left ventricular wall, measured under histopathological examination. In conclusion, IR for 30 minutes caused only small changes in LV diastolic function, assessed by tissue Doppler; however, the IR was not effective for promoting HF, as observed with CAL. Thus, it is possible that prolonged IR is necessary for promoting significant HF in rats.


2000 ◽  
Vol 279 (2) ◽  
pp. H844-H851 ◽  
Author(s):  
Eric Thorin ◽  
Martin Lucas ◽  
Peter Cernacek ◽  
Jocelyn Dupuis

Endothelium-derived nitric oxide (NO) and endothelin (ET)-1 interact to regulate vascular tone. In congestive heart failure (CHF), the release and/or the activity of both factors is affected. We hypothesized that the increased ET-1 production associated with CHF may result in a reduced smooth muscle sensitivity to NO. The aim of this study was to evaluate the effects of a chronic treatment with the ETA-receptor (ET receptor A) antagonist LU-135252 (LU) on cerebrovascular reactivity to sodium nitroprusside (SNP) in the rat infarct model of CHF. Rats were subjected to coronary artery ligation and were treated for 4 wk with placebo ( n = 24) or LU (50 mg · kg−1 · day−1, n = 29). CHF was associated with a decreased ( P < 0.05) efficacy of SNP to induce relaxation of isolated middle cerebral arteries. Furthermore, neither NO synthase inhibition with N ω-nitro-l-arginine (l-NNA) nor endothelial denudation affected the efficacy of SNP. Thus the endothelium no longer influences smooth muscle sensitivity to SNP. LU treatment, however, normalized ( P < 0.05) smooth muscle sensitivity to SNP. Sensitivity of ET-1-induced contraction was increased in CHF only in the presence of l-NNA, whereas contraction induced by ETB receptor (receptor B) stimulation was increased ( P < 0.05) in endothelium-denuded vessels. LU treatment restored these changes in reactivity and revealed a significant endothelium-dependent ETB-mediated relaxation after NO synthase inhibition. In conclusion, CHF decreases and uncouples cerebrovascular smooth muscle sensitivity to SNP from endothelial regulation. The observation that chronic ETAblockade restored most of the changes associated with CHF suggests that activation of the ET-1 system importantly contributes to the alteration in vascular reactivity observed in experimental CHF.


1991 ◽  
Vol 261 (6) ◽  
pp. H1979-H1987 ◽  
Author(s):  
M. Gopalakrishnan ◽  
D. J. Triggle ◽  
A. Rutledge ◽  
Y. W. Kwon ◽  
J. A. Bauer ◽  
...  

To examine the status of ATP-sensitive K+ (K+ATP) channels and 1,4-dihydropyridine-sensitive Ca2+ (Ca2+DHP) channels during experimental cardiac failure, we have measured the radioligand binding properties of [3H]glyburide and [3H]PN 200 110, respectively, in tissue homogenates from the rat cardiac left ventricle, right ventricle, and brain 4 wk after myocardial infarction induced by left coronary artery ligation. The maximal values (Bmax) for [3H]glyburide and [3H]PN 200 110 binding were reduced by 39 and 40%, respectively, in the left ventricle, and these reductions showed a good correlation with the right ventricle-to-body weight ratio in heart-failure rats. The ligand binding affinities were not altered. In the hypertrophied right ventricle, Bmax values for both the ligands were not significantly different when data were normalized to DNA content or right ventricle weights but showed an apparent reduction when normalized to unit protein or tissue weight. Moderate reductions in channel densities were observed also in whole brain homogenates from heart failure rats. Assessment of muscarinic receptors, beta-adrenoceptors and alpha 1-adrenoceptors by [3H]quinuclidinyl benzilate, [3H]dihydroalprenolol, and [3H]prazosin showed reductions in left ventricular muscarinic and beta-adrenoceptor densities but not in alpha 1-adrenoceptor densities, consistent with earlier observations. It is suggested that these changes may in part contribute to the pathology of cardiac failure.


Circulation ◽  
2014 ◽  
Vol 130 (suppl_2) ◽  
Author(s):  
S. J Sangaralingham ◽  
Tomoko Ichiki ◽  
Gerald E Harders ◽  
Horng H Chen ◽  
John C Burnett

Introduction: The incidence of post-myocardial infarction (MI) heart failure (HF) is increasing in the elderly. Studies have demonstrated that B-type natriuretic peptide (BNP) mediates critical cardiorenal compensatory and protective actions through guanylyl cyclase receptor A and cGMP activation. Such actions include natriuresis, diuresis and suppression of adverse cardiorenal remodelling. Hypothesis: While the mechanism of this increased risk may be multifactorial, we hypothesized that an impairment of the compensatory protective BNP/cGMP axis in both the aged kidney and heart contributes to post-MI HF. Methods: 20 month old Fischer rats were randomized into two groups: Sham-operated (S) and MI(produced by left coronary artery ligation). Cardiorenal structure and function were assessed at 4 weeks and included mean arterial pressure(MAP), LV EF, LV chamber dimension, proteinuria, sodium (Na) excretion and fibrosis by picrosirius red staining. Plasma BNP and cGMP levels were assessed by RIA. Data presented as mean±SE,*P<0.05. Results: LV EF (S:78±2, MI:46±3 %*) was significantly reduced in aged MI rats, despite no difference in LV fibrosis in the remote region and no change in MAP compared to aged sham rats. Post-MI HF was evident and characterized by a significant reduction in Na excretion (S:0.20±0.03, MI:0.13±0.01 mEq/day*) as well as significant increases in LV dilatation (S:7.2±0.1, MI:8.3±0.2 mm*) and cardiac hypertrophy (S:2.78±0.06, MI:3.25±0.16 mg/g*) in aged MI rats. Notably, plasma BNP (S:9±1, MI:11±2 pg/ml) failed to increase and plasma cGMP (S:44±6, MI:27±3 mm*) was significantly reduced in the MI group. Importantly, MI in the aged rat resulted in a significant loss in total renal mass (S:2739±83, MI:2351±68 mg*), consistent with renal atrophy, while no changes in proteinuria or renal fibrosis were observed. Conclusions: Post-MI dysfunction of the protective BNP/cGMP axis in the aged rat was associated with various cardiorenal abnormalities including renal atrophy, which may contribute to the pathophysiology of HF. This pre-clinical model provides new insights into post-MI HF and may be used to examine therapeutic strategies using natriuretic peptides to protect the heart and kidney in the elderly post-MI population.


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