scholarly journals N-acetyl Cysteine, Selenium, and Ascorbic Acid Rescue Diabetic Cardiac Hypertrophy via Mitochondrial-Associated Redox Regulators

Molecules ◽  
2021 ◽  
Vol 26 (23) ◽  
pp. 7285
Author(s):  
Iram Mushtaq ◽  
Zainab Bashir ◽  
Mehvish Sarwar ◽  
Maria Arshad ◽  
Ayesha Ishtiaq ◽  
...  

Metabolic disorders often lead to cardiac complications. Metabolic deregulations during diabetic conditions are linked to mitochondrial dysfunctions, which are the key contributing factors in cardiac hypertrophy. However, the underlying mechanisms involved in diabetes-induced cardiac hypertrophy are poorly understood. In the current study, we initially established a diabetic rat model by alloxan-administration, which was validated by peripheral glucose measurement. Diabetic rats displayed myocardial stiffness and fibrosis, changes in heart weight/body weight, heart weight/tibia length ratios, and enhanced size of myocytes, which altogether demonstrated the establishment of diabetic cardiac hypertrophy (DCH). Furthermore, we examined the expression of genes associated with mitochondrial signaling impairment. Our data show that the expression of PGC-1α, cytochrome c, MFN-2, and Drp-1 was deregulated. Mitochondrial-signaling impairment was further validated by redox-system dysregulation, which showed a significant increase in ROS and thiobarbituric acid reactive substances, both in serum and heart tissue, whereas the superoxide dismutase, catalase, and glutathione levels were decreased. Additionally, the expression levels of pro-apoptotic gene PUMA and stress marker GATA-4 genes were elevated, whereas ARC, PPARα, and Bcl-2 expression levels were decreased in the heart tissues of diabetic rats. Importantly, these alloxan-induced impairments were rescued by N-acetyl cysteine, ascorbic acid, and selenium treatment. This was demonstrated by the amelioration of myocardial stiffness, fibrosis, mitochondrial gene expression, lipid profile, restoration of myocyte size, reduced oxidative stress, and the activation of enzymes associated with antioxidant activities. Altogether, these data indicate that the improvement of mitochondrial dysfunction by protective agents such as N-acetyl cysteine, selenium, and ascorbic acid could rescue diabetes-associated cardiac complications, including DCH.

2020 ◽  
Vol 127 (Suppl_1) ◽  
Author(s):  
Yuening Liu ◽  
Peng Xia ◽  
Jingrui Chen ◽  
Patricia W Bandettini ◽  
Lawrence S Kirschner ◽  
...  

Protein kinase A (PKA) is pivotal for cardiac function of human heart, and its dysregulation is involved with various cardiac pathologies. PKA regulatory subunit 1α (R1α, encoded by PRKAR1A gene) controls PKA kinase activity by sequestering the PKA catalytic subunits. Patients with PRKAR1A mutations are often diagnosed with Carney complex (CNC) and may die prematurely from cardiac complications such as heart failure. However, it remains unknown whether PRKAR1A deficiency interferes with normal heart growth during postnatal development. Here, we show that left ventricular mass is reduced in young CNC patients with PRKAR1A mutations or deletions. To investigate the impact of PRKAR1A deficiency on heart growth, we generated cardiac-specific PRKAR1A heterozygous knockout mice. Ablation of the PRKAR1A gene in mice increased cardiac PKA activity, reduced heart weight to body weight ratio and cardiomyocyte size without altering contractile function. Cardiomyocyte hypertrophy in response to activation of the α1-adrenergic receptor, was completely abolished by silencing of PRKAR1A . Mechanistically, depletion of PRKAR1A provoked PKA-dependent phosphorylation of the mitochondrial fission protein Drp1 at S637, resulting in impaired mitochondrial fission and diminished cardiomyocyte hypertrophy. In conclusion, PRKAR1A deficiency abrogates cardiac hypertrophy during postnatal development, likely through inhibiting Drp1-mediated mitochondrial fission. Our study provides novel mechanistic insights regarding the cardiac mortality associated with CNC.


2019 ◽  
Vol 40 (Supplement_1) ◽  
Author(s):  
A Ishikita ◽  
S Matsushima ◽  
S Ikeda ◽  
K Okabe ◽  
T Tadokoro ◽  
...  

Abstract Background Cardiac hypertrophy is an independent risk factor for heart failure and cardiac death. Hexosamine biosynthesis pathway (HBP), an accessory pathways of glycolysis, is known to be involved in the attachment of O-linked N-acetylglucosamine motif (O-GlcNAcylation) to proteins, a post-translational modification. However, the role of HBP has not been determined in pathological cardiac hypertrophy. Purpose The purpose of this study to examine whether glutamine-fructose-6-phosphate amidotransferase 2 (GFAT2), a critical enzyme of HBP, mediates cardiac hypertrophy by protein O-GlcNAcylation and activating hypertrophic signaling in cardiomyocytes. Methods and results C57BL/6J mice were treated with isoproterenol (ISO: 15 mg/kg/day, 1 week) with or without 6-Diazo-5-oxo-L-norleucine (DON, an inhibitor of GFAT: 500 μg/kg/day, 1week). ISO-treated mice (ISO+vehicle) showed cardiac hypertrophy, which were attenuated in ISO and DON-treated mice (ISO+DON) (heart weight to tibial length ratio: 7.70±0.09 vs. 7.11±0.15 mg/mm, n=12, p<0.05, left ventricular wall thickness: 1.05±0.02 vs. 0.86±0.03 mm, n=6, p<0.05). Cardiomyocyte cross-sectional area was also decreased in ISO+DON compared with ISO+vehicle (309±25 vs. 252±13 mm2, n=,3 p<0.05). Whereas expression levels of GFAT2 and protein O-GlcNAcylation in the heart were increased in ISO+vehicle compared with control+vehicle by 3.3 and 1.5 folds, respectively (n=9 and n=9, p<0.05), expression levels of O-GlcNAc transferase (OGT) and the β-N-acetylglucosaminidase (OGA), other enzymes regulating O-GlcNAcylation, were not altered in both groups, indicating that ISO activated HBP by GFAT2. Protein O-GlcNAcylation in ISO+DON was lower than that in ISO+vehicle by 83% (n=9, p<0.05). In addition, phosphorylation of Akt, a critical mediator of cardiac hypertrophy, but not other mediators of cardiac hypertrophy such as ERK, JNK, or p38MAPK, was significantly decreased in ISO+DON by 76% (n=9, p<0.05). In cultured neonatal rat ventricular myocytes, treatment with ISO (1μM, 12h) increased the expression levels of GFAT2 and protein O-GlcNAcylation by 1.3 and 1.5 folds, respectively (n=6 and n=6, p<0.05), but not GFAT1. Furthermore, ISO stimulation increased a direct O-GlcNAcylation of Akt by 1.4 folds (n=3, p<0.05). Downregulation of GFAT2 by RNA silencing decreased cell size by 82% (n=6, p<0.05) and protein O-GlcNAcylation and phosphorylation of Akt by 76% and 54%, respectively (n=9 and n=9, p<0.05) in cardiomyocyte treated with ISO. Conversely, administration of glucosamine, a substrate of HBP, increased protein of O-GlcNAcylation and phosphorylation of Akt by 1.3 and 1.8 folds, respectively (n=6 and n=6, p<0.05). Conclusions GFAT2, a limiting enzyme of HBP, mediates pathological cardiac hypertrophy by Akt activation probably due to its O-GlcNAcylation. GFAT2-O-GlcNAcylation-Akt pathway might be a potential novel therapeutic target for cardiac hypertrophy.


2020 ◽  
Vol 13 (1) ◽  
pp. 76-83
Author(s):  
Aline Maria Brito Lucas ◽  
Joana Varlla de Lacerda Alexandre ◽  
Maria Thalyne Silva Araújo ◽  
Cicera Edna Barbosa David ◽  
Yuana Ivia Ponte Viana ◽  
...  

Background: Cardiac hypertrophy involves marked wall thickening or chamber enlargement. If sustained, this condition will lead to dysfunctional mitochondria and oxidative stress. Mitochondria have ATP-sensitive K+ channels (mitoKATP) in the inner membrane that modulate the redox status of the cell. Objective: We investigated the in vivo effects of mitoKATP opening on oxidative stress in isoproterenol- induced cardiac hypertrophy. Methods: Cardiac hypertrophy was induced in Swiss mice treated intraperitoneally with isoproterenol (ISO - 30 mg/kg/day) for 8 days. From day 4, diazoxide (DZX - 5 mg/kg/day) was used in order to open mitoKATP (a clinically relevant therapy scheme) and 5-hydroxydecanoate (5HD - 5 mg/kg/day) or glibenclamide (GLI - 3 mg/kg/day) were used as mitoKATP blockers. Results: Isoproterenol-treated mice had elevated heart weight/tibia length ratios (HW/TL). Additionally, hypertrophic hearts had elevated levels of carbonylated proteins and Thiobarbituric Acid Reactive Substances (TBARS), markers of protein and lipid oxidation. In contrast, mitoKATP opening with DZX avoided ISO effects on gross hypertrophic markers (HW/TL), carbonylated proteins and TBARS, in a manner reversed by 5HD and GLI. Moreover, DZX improved mitochondrial superoxide dismutase activity. This effect was also blocked by 5HD and GLI. Additionally, ex vivo treatment of isoproterenol- induced hypertrophic cardiac tissue with DZX decreased H2O2 production in a manner sensitive to 5HD, indicating that this drug also acutely avoids oxidative stress. Conclusion: Our results suggest that diazoxide blocks oxidative stress and reverses cardiac hypertrophy. This pharmacological intervention could be a potential therapeutic strategy to prevent oxidative stress associated with cardiac hypertrophy.


2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Yi Wang ◽  
Hongjuan Liao ◽  
Yueheng Wang ◽  
Jinlin Zhou ◽  
Feng Wang ◽  
...  

Abstract Background Cardiovascular diseases have become the leading cause of death worldwide, and cardiac hypertrophy is the core mechanism underlying cardiac defect and heart failure. However, the underlying mechanisms of cardiac hypertrophy are not fully understood. Here we investigated the roles of Kallikrein 11 (KLK11) in cardiac hypertrophy. Methods Human and mouse hypertrophic heart tissues were used to determine the expression of KLK11 with quantitative real-time PCR and western blot. Mouse cardiac hypertrophy was induced by transverse aortic constriction (TAC), and cardiomyocyte hypertrophy was induced by angiotensin II. Cardiac function was analyzed by echocardiography. The signaling pathway was analyzed by western blot. Protein synthesis was monitored by the incorporation of [3H]-leucine. Gene expression was analyzed by quantitative real-time PCR. Results The mRNA and protein levels of KLK11 were upregulated in human hypertrophic hearts. We also induced cardiac hypertrophy in mice and observed the upregulation of KLK11 in hypertrophic hearts. Our in vitro experiments demonstrated that KLK11 overexpression promoted whereas KLK11 knockdown repressed cardiomyocytes hypertrophy induced by angiotensin II, as evidenced by cardiomyocyte size and the expression of hypertrophy-related fetal genes. Besides, we knocked down KLK11 expression in mouse hearts with adeno-associated virus 9. Knockdown of KLK11 in mouse hearts inhibited TAC-induced decline in fraction shortening and ejection fraction, reduced the increase in heart weight, cardiomyocyte size, and expression of hypertrophic fetal genes. We also observed that KLK11 promoted protein synthesis, the key feature of cardiomyocyte hypertrophy, by regulating the pivotal machines S6K1 and 4EBP1. Mechanism study demonstrated that KLK11 promoted the activation of AKT-mTOR signaling to promote S6K1 and 4EBP1 pathway and protein synthesis. Repression of mTOR with rapamycin blocked the effects of KLK11 on S6K1 and 4EBP1 as well as protein synthesis. Besides, rapamycin treatment blocked the roles of KLK11 in the regulation of cardiomyocyte hypertrophy. Conclusions Our findings demonstrated that KLK11 promoted cardiomyocyte hypertrophy by activating AKT-mTOR signaling to promote protein synthesis.


2017 ◽  
Vol 370 (2) ◽  
pp. 305-317 ◽  
Author(s):  
M. Verónica Aguirre-Arias ◽  
Victoria Velarde ◽  
Ricardo D. Moreno

2016 ◽  
Vol 2016 ◽  
pp. 1-7 ◽  
Author(s):  
Ying Yu ◽  
Xian-Jie Jia ◽  
Wei-ping Zhang ◽  
Ting-ting Fang ◽  
Jie Hu ◽  
...  

Objective. To investigate the effects of low dose ethanol feeding in diabetic rats and analyze its underlying mechanisms.Methods. Male Sprague-Dawley rats were divided into 4 groups: control (Con), diabetes at 4 weeks (DM4W), diabetes at 8 weeks (DM8W), and EtOH + DM8W. After 8 weeks, hemodynamic parameters were recorded and heart weight/body weight (H/B) and hydroxyproline (Hp) content in myocardium were measured. Morphology of collagen in myocardial tissue was observed with Masson’s trichrome staining method and collagen volume fraction (CVF) was analysed. The mRNA expression of ALDH2 was assessed with Real-Time PCR. The protein expressions of p-JNK and JNK were evaluated using western blot.Results. In contrast to Con group, there was no difference in hemodynamic parameters in DM4W group, but mean arterial pressure and heart rate were decreased in DM8W group, and the ratios of H/B, Hp, and CVF were markedly increased. ALDH2 mRNA expression was decreased, while the ratio of p-JNK/JNK were increased. Compared with DM8W group, the above indexes were improved in EtOH + DM8W group.Conclusion. With low dose ethanol intervention, enhanced ALDH2 expression can antagonize the happening of myocardial fibrosis in diabetic rats, which may be relevant with downregulating the JNK pathway.


Circulation ◽  
2020 ◽  
Vol 142 (Suppl_3) ◽  
Author(s):  
Raihan Kabir ◽  
Prithvi Sinha ◽  
Sumita Mishra ◽  
Obialunanma V Ebenebe ◽  
Nicole Taube ◽  
...  

Exposure to inorganic arsenic (iAS) through drinking water is well-associated with adverse cardiovascular outcomes, yet the mechanisms through which it induces these effects are not fully understood. Recent epidemiological findings highlight an association between iAS exposure and altered left ventricular geometry in both the presence and absence of hypertension. We therefore tested the hypothesis that iAS exposure has a bimodal impact on cardiac-intrinsic and hemodynamic mechanisms that together induce pathological remodeling of the myocardium. Adult male and female mice were exposed to an environmentally relevant dose of 615 μg/L NaAsO 2 for eight weeks. Males (n=9-10 mice/group) exhibited increased systolic blood pressure (115.1±3.0 vs. 106.0±2.3 mmHg, p=0.0350) via tail cuff photoplethysmography, left ventricular wall thickening (0.98±0.01 vs. 0.88±0.01 mm, p<0.0001) via transthoracic echocardiography, increased heart weight to tibia length (8.56±0.21 vs. 7.15±0.24 mg/mm; n=24 mice/group), and increased plasma atrial natriuretic peptide (47.85±12.0 vs. 15.14±3.73 pg/mL, p=0.0379) via enzyme immunoassay. Myocardial mRNA transcript levels (n=10 hearts/group) of Acta1 (1.36±0.18 vs. 0.73±0.11, p=0.0037), Myh7 (1.53±0.15 vs. 1.04±0.10, p=0.0138), and Nppa (2.40±0.29 vs. 1.02±0.07, p=0.0001) were increased, and Myh6 (0.92±0.17 vs. 1.14±0.23, p=0.0001) was decreased, evidencing pathological hypertrophy in the male heart. Female hearts, however, were largely protected at this eight-week timepoint as similar changes were not detected. Further investigation found that Rcan1 was upregulated (1.47±0.19 vs. 0.97±0.04, p=0.0161; n=10 hearts/group) in male hearts, suggesting that calcineurin-NFAT was activated. Interestingly, iAS was sufficient to activate NFAT (0.82±0.11 vs. 0.46±0.05, p=0.0214; n=8 wells/group) independent of blood pressure via luciferase assay. In conclusion, these results demonstrate for the first time that iAS may cause pathological cardiac hypertrophy not only by increasing hemodynamic load, but also by activating calcineurin-NFAT and inducing fetal gene expression in the male heart, thus providing novel mechanistic insight into the threat of iAS exposure to the cardiovascular system.


Circulation ◽  
2014 ◽  
Vol 130 (suppl_2) ◽  
Author(s):  
Sally K Hammad ◽  
Min Zi ◽  
Sukhpal Prehar ◽  
Robert Little ◽  
Ludwig Neyses ◽  
...  

Introduction: Hypertension is a major risk factor for cardiac hypertrophy and heart failure. Genome wide association studies have recently identified single nucleotide polymorphisms in ATP2B1 , the gene encoding the calcium extrusion pump, plasma membrane calcium ATPase (PMCA1), as having a strong association with hypertension risk. Hypothesis: PMCA1 plays an important role in regulation of blood pressure and protection against hypertension and cardiac hypertrophy. Aims: We aim to examine whether there is a functional link between PMCA1 and blood pressure regulation, and the development of hypertension. And to determine the impact this link may have on cardiac structure and function. Methods and Results: To study the role of PMCA1 we generated a global PMCA1 heterozygous knockout mouse (PMCA1 Ht ). PMCA1 Ht mice had 46% to 52% reduction in PMCA1 protein expression compared to the WT, in aorta, heart, kidney and brain. To study the mice under hypertensive stress conditions, 3 month old PMCA1 Ht and wild type (WT) mice were infused via minipump with angiotensin II (1mg/Kg/daily) or water as a control. Upon angiotensin treatment, PMCA1 Ht mice showed a significantly greater increase in systolic (62.24±3.05 mmHg) and diastolic pressure (52.68±4.67 mmHg), in comparison to the WT (33.37±2.91 mmHg and 23.94±4.56 mmHg, respectively), P<0.001, n=12. Moreover, PMCA1 Ht mice showed a significantly greater hypertrophic response as indicated by a greater heart weight to tibia length ratio, cardiomyocyte cell size (410±18.7 μm 2 ), compared to WT mice (340.4±9.8 μm 2 ), and increased expression of B-type natriuretic peptide (BNP), 2.36 ± 0.25 fold change, n =5-6, P< 0.01. Echocardiography showed no significant changes between PMCA1 Ht and WT mice, in heart rate, and in cardiac function, as indicated by fractional shortening and ejection fraction. In addition, PMCA1 Ht mice showed no sign of lung congestion as indicated by lung weight to body weight ratio. Conclusion: ATP2B1 deletion leads to increased blood pressure and cardiac hypertrophy. This provides functional evidence that PMCA1 is involved in blood pressure regulation and protects against the development of hypertension and cardiac hypertrophy.


2015 ◽  
Vol 117 (suppl_1) ◽  
Author(s):  
Christopher J Traynham ◽  
Ancai Yuan ◽  
Erhe Gao ◽  
Walter Koch

In the next 35 years, the global population of individuals above 60 years of age will double to approximately 2 billion. In the aged population, cardiovascular diseases are known to occur at a higher prevalence ultimately leading to increased mortality. G protein-coupled receptors (GPCRs) have been identified as vital regulators of cardiac function. GPCR kinases (GRKs) are important in cardiac GPCR regulation through desensitization of these receptors. GRK2 is highly expressed in the heart, and has been widely characterized due to its upregulation in heart failure. Studies from our lab have shown that elevated GRK2 levels in ischemia-reperfusion (I/R) injury result in a pro-death phenotype. Interestingly, cardio-protection can be inferred via S-nitrosylation of GRK2 at cysteine 340. Further, we have generated a knock-in GRK2 340S mouse, in which cysteine 340 was mutated to block dynamic GRK2 S-nitrosylation. GRK2 340S mice are more susceptible to I/R injury. Given that GRK2 340S mice are more susceptible to oxidative stress, and there is a nitroso-redox imbalance in senescence, it is possible that these mice are more likely to exhibit decreased cardiac performance as they age. Therefore, we hypothesize that with age GRK2 340S knockin mice will develop an overall worsened cardiac phenotype compared to control wild-type (WT) mice. To test this hypothesis, 340S and WT mice were aged for a year, and cardiac function was evaluated via echocardiography. Aged 340S mice exhibited significantly decreased ejection fraction and fraction shortening relative to aged WT controls. Prior to tissue harvesting, in-vivo hemodynamics was conducted via Millar catheterization. At baseline, aged 340S mice exhibited increased systolic blood pressure compared to aged WT mice. At the conclusion of this protocol, mice were sacrificed and heart weight (HW), body weight (BW), and tibia length (TL) measured to evaluate cardiac hypertrophy. Aged 340S mice exhibited significantly increased HW/BW and HW/TL ratios, indicative of cardiac hypertrophy, relative to aged WT controls. Taken together, these data suggest that with age, loss of the cardio protection inferred by S-nitrosylation of GRK2 at leads to decreased cardiac performance, and an overall worsened cardiac phenotype.


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