CaMKII activation and necroptosis augment in diabetic cardiomyopathy via a RIPK3-dependent manner

Activation of Ca2+/calmodulin-dependent protein kinase (CaMKII) has been proved to play a vital role in cardiovascular diseases. Receptor-interaction protein kinase 3- (RIPK3-) mediated necroptosis has crucially participated in cardiac dysfunction. The study is aimed at investigating the effect as well as the mechanism of CaMKII activation and necroptosis on diabetic cardiomyopathy (DCM). Wild-type (WT) and the RIPK3 gene knockout (RIPK3-/-) mice were intraperitoneally injected with 60 mg/kg/d streptozotocin (STZ) for 5 consecutive days. After 12 w of feeding, 100 μL recombinant adenovirus solution carrying inhibitor 1 of protein phosphatase 1 (I1PP1) gene was injected into the caudal vein of mice. Echocardiography, myocardial injury, CaMKII activity, necroptosis, RIPK1 expression, mixed lineage kinase domain-like protein (MLKL) phosphorylation, and mitochondrial ultrastructure were measured. The results showed that cardiac dysfunction, CaMKII activation, and necroptosis were aggravated in streptozotocin- (STZ-) stimulated mice, as well as in (Lepr) KO/KO (db/db) mice. RIPK3 deficiency alleviated cardiac dysfunction, CaMKII activation, and necroptosis in DCM. Furthermore, I1PP1 overexpression reversed cardiac dysfunction, myocardial injury and necroptosis augment, and CaMKII activity enhancement in WT mice with DCM but not in RIPK3-/- mice with DCM. The present study demonstrated that CaMKII activation and necroptosis augment in DCM via a RIPK3-dependent manner, which may provide therapeutic strategies for DCM.

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FGF1ΔHBS prevents diabetic cardiomyopathy by maintaining mitochondrial homeostasis and reducing oxidative stress via AMPK/Nur77 suppression

Signal Transduction and Targeted Therapy ◽

10.1038/s41392-021-00542-2 ◽

2021 ◽

Vol 6 (1) ◽

Author(s):

Dezhong Wang ◽

Yuan Yin ◽

Shuyi Wang ◽

Tianyang Zhao ◽

Fanghua Gong ◽

...

Keyword(s):

Diabetic Cardiomyopathy ◽

Metabolic Regulation ◽

Cardiac Injury ◽

Serum Levels ◽

Ros Generation ◽

Dependent Manner ◽

Cardiac Tissues ◽

Beneficial Effects

AbstractAs a classically known mitogen, fibroblast growth factor 1 (FGF1) has been found to exert other pleiotropic functions such as metabolic regulation and myocardial protection. Here, we show that serum levels of FGF1 were decreased and positively correlated with fraction shortening in diabetic cardiomyopathy (DCM) patients, indicating that FGF1 is a potential therapeutic target for DCM. We found that treatment with a FGF1 variant (FGF1∆HBS) with reduced proliferative potency prevented diabetes-induced cardiac injury and remodeling and restored cardiac function. RNA-Seq results obtained from the cardiac tissues of db/db mice showed significant increase in the expression levels of anti-oxidative genes and decrease of Nur77 by FGF1∆HBS treatment. Both in vivo and in vitro studies indicate that FGF1∆HBS exerted these beneficial effects by markedly reducing mitochondrial fragmentation, reactive oxygen species (ROS) generation and cytochrome c leakage and enhancing mitochondrial respiration rate and β-oxidation in a 5’ AMP-activated protein kinase (AMPK)/Nur77-dependent manner, all of which were not observed in the AMPK null mice. The favorable metabolic activity and reduced proliferative properties of FGF1∆HBS testify to its promising potential for use in the treatment of DCM and other metabolic disorders.

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Abstract 214: MicroRNA-451 Aggravates Lipotoxic Cardiomyopathy Through Suppression of the LKB1/AMPK Signaling Pathway

Circulation Research ◽

10.1161/res.117.suppl_1.214 ◽

2015 ◽

Vol 117 (suppl_1) ◽

Author(s):

Yasuhide Kuwabara ◽

Takahiro Horie ◽

Osamu Baba ◽

Toru Kita ◽

Takeshi Kimura ◽

...

Keyword(s):

Cardiac Hypertrophy ◽

Diabetic Cardiomyopathy ◽

Calcium Binding ◽

Saturated Fatty Acids ◽

Mammalian Target Of Rapamycin ◽

Neonatal Rat ◽

Albumin Concentration ◽

Dependent Manner ◽

Ceramide Level

Rationale: In some type 2 diabetes mellitus (T2D) patients without hypertension, cardiac hypertrophy and attenuated cardiac function are observed, and this insult is termed “diabetic cardiomyopathy.” Tons of evidence suggests that microRNAs are involved in cardiac diseases. However, the functions of microRNAs in the diabetic cardiomyopathy induced by T2D and obesity are not fully understood. Methods and Results: C57BL/6 mice were fed a high-fat diet (HFD) for 20 weeks, which induced obesity and T2D. MicroRNA microarray and real-time PCR revealed that miR-451 levels were significantly increased in the T2D mouse hearts (n=4-5, p<0.05). Because excess supply of saturated fatty acids is a cause of diabetic cardiomyopathy, we stimulated neonatal rat cardiac myocytes (NRCMs) with palmitate in physiological albumin concentration and confirmed that miR-451 expression was increased in a dose-dependent manner (n=6-12, p<0.01). Loss of miR-451 function ameliorated palmitate-induced lipotoxicity in NRCMs (n=4, p<0.05). Calcium-binding protein 39 (Cab39) is a scaffold protein of liver kinase B1 (LKB1), an upstream kinase of AMP-activated protein kinase (AMPK). Cab39 was a direct target of miR-451 in NRCMs and Cab39 overexpression rescued the palmitate-induced lipotoxicity in NRCMs (n=4, p<0.01). To clarify miR-451 functions in vivo, we generated cardiomyocyte-specific miR-451 knockout (cKO) mice. HFD-induced cardiac hypertrophy and contractile reserves were ameliorated in cKO mice compared with HFD-fed control mice. Protein levels of Cab39 and phosphorylated AMPK were increased and phosphorylated mammalian target of rapamycin (mTOR) was reduced in HFD-fed cKO mouse hearts compared with HFD-fed control mouse hearts (n=10-12, p<0.05). We also measured the lipotoxic intermediates, triglyceride and ceramide, in these mouse hearts using HPLC-evaporative light scattering detector (ELSD). Although there was no difference in triglyceride levels (n=3-5), ceramide level was decreased in HFD-fed cKO mice compared with HFD-fed control mice (n=3-5, p<0.05). Conclusions: Our results indicate that miR-451 exacerbates diabetic cardiomyopathy. miR-451 is a potential therapeutic target for cardiac disease caused by T2D and obesity.

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Diabetes induces and calcium channel blockers prevent cardiac expression of proapoptotic thioredoxin-interacting protein

AJP Endocrinology and Metabolism ◽

10.1152/ajpendo.90944.2008 ◽

2009 ◽

Vol 296 (5) ◽

pp. E1133-E1139 ◽

Cited By ~ 59

Author(s):

Junqin Chen ◽

Hyunjoo Cha-Molstad ◽

Anna Szabo ◽

Anath Shalev

Keyword(s):

Calcium Channel ◽

Diabetic Cardiomyopathy ◽

Calcium Channel Blockers ◽

Caspase 3 ◽

Critical Role ◽

Cardiomyocyte Apoptosis ◽

Channel Blockers ◽

Dependent Manner ◽

Interacting Protein ◽

Thioredoxin Interacting Protein

Cardiomyocyte apoptosis is a critical process in the pathogenesis of ischemic and diabetic cardiomyopathy, but the mechanisms are not fully understood. Thioredoxin-interacting protein (TXNIP) has recently been shown to have deleterious effects in the cardiovascular system and we therefore investigated whether it may also play a role in diabetes-associated cardiomyocyte apoptosis. In fact, TXNIP expression was increased in H9C2 cardiomyocytes incubated at high glucose, and cardiac expression of TXNIP and cleaved caspase-3 were also elevated in vivo in streptozotocin- and obesity-induced diabetic mice. Together, these findings not only suggest that TXNIP is involved in diabetic cardiomyopathy but also that it may represent a novel therapeutic target. Surprisingly, testing putative TXNIP modulators revealed that calcium channel blockers reduce cardiomyocyte TXNIP transcription and protein levels in a dose-dependent manner. Oral administration of verapamil for 3 wk also reduced cardiac TXNIP expression in mice even in the face of severe diabetes, and these reduced TXNIP levels were associated with decreased apoptosis. To determine whether lack of TXNIP can mimic the verapamil-induced decrease in apoptosis, we used TXNIP-deficient HcB-19 mice, harboring a natural nonsense mutation in the TXNIP gene. Interestingly, we found significantly reduced cleaved caspase-3 levels in HcB-19 hearts, suggesting that TXNIP plays a critical role in cardiac apoptosis and that the verapamil effects were mediated by TXNIP reduction. Thus our results suggest that TXNIP reduction is a powerful target to enhance cardiomyocyte survival and that agents such as calcium channel blockers may be useful in trying to achieve this goal and prevent diabetic cardiomyopathy.

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Identification of Energy Metabolism Changes in Diabetic Cardiomyopathy Rats Using a Metabonomic Approach

Cellular Physiology and Biochemistry ◽

10.1159/000491960 ◽

2018 ◽

Vol 48 (3) ◽

pp. 934-946 ◽

Cited By ~ 3

Author(s):

Liangcai Zhao ◽

Minjian Dong ◽

Cuicui Xu ◽

Hong Zheng ◽

Tingting Wei ◽

...

Keyword(s):

Diabetic Cardiomyopathy ◽

Drug Targets ◽

Tca Cycle ◽

High Energy ◽

Diabetic Rats ◽

Metabolic Changes ◽

Dependent Manner ◽

Cardiac Tissues ◽

1H Nuclear Magnetic Resonance ◽

Energy Synthesis

Background/Aims: Diabetic cardiomyopathy (DCM) is a serious complication of diabetes. It is therefore crucial to elucidate the characteristic metabolic changes that occur during the development of diabetes to gain an understanding the pathogenesis of this disease and identify potential drug targets involved. Methods: 1H nuclear magnetic resonance-based metabonomics combined with HPLC measurements were used to determine the metabolic changes in isolated cardiac tissues after 5 weeks, 9 weeks, and 15 weeks in rats treated with streptozotocin. Results: Pattern recognition analysis clearly discriminated the diabetic rats from time-matched control rats, suggesting that the metabolic profile of the diabetic group was markedly different from that of the controls. Quantitative analysis showed that the levels of energy metabolites, such as the high-energy phosphate pool (ATP and creatine), significantly decreased in a time-dependent manner. Correlation analysis revealed the inhibition of glycolysis and the tricarboxylic acid (TCA) cycle, enhanced lipid metabolism, and changes in some amino acids, which may have led to the decline in energy production in the DCM rats. Conclusions: The results indicated that the administration of energy substances or the manipulation of myocardial energy synthesis induced by increased glucose oxidation may contribute to the amelioration of cardiac dysfunction in diabetes.

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Dapagliflozin Attenuates Diabetic Cardiomyopathy Through Erythropoietin Up-Regulation of AKT/JAK/MAPK Pathways in Streptozotocin-Induced Diabetic Rats

10.21203/rs.3.rs-472044/v1 ◽

2021 ◽

Author(s):

Nora El-Sayed ◽

Yasser M. Mostafa ◽

Noha M AboGresha ◽

Amal A.M. Ahmed ◽

Islam Z. Mahmoud ◽

...

Keyword(s):

Diabetic Cardiomyopathy ◽

Diabetic Rats ◽

Cardiac Cells ◽

Control Group ◽

Histological Structure ◽

Dependent Manner ◽

Functional Changes ◽

Mapk Cascades ◽

Group 2 ◽

Histopathological Studies

Abstract Purpose: This study was designed to investigate the mechanism of Dapagliflozin (Dapa) cardioprotection against diabetic cardiomyopathy (DCM). Structural and functional changes in the heart as well as decrease of Erythropoietin (EPO) levels were reported in DCM. EPO simultaneously activates three pathways: the Janus-activated kinase–signal transducer and activator of transcription (JAK2/STAT5), phosphatidylinositol-3-kinase-Akt (PI3K/Akt), and extracellular signal-related kinase (ERK/MAPK) cascades, that result in proliferation and differentiation of cardiac cells.Methods and Results: DCM was induced by a high fat diet for 10 weeks followed by administration of streptozotocin. After confirmation of diabetes, rats were divided randomly to 5 groups: Group 1; normal control group, Group 2; untreated diabetic group and Groups (3-5); diabetic groups received Dapa daily (0.75 mg, 1.5 or 3 mg /Kg, p.o) respectively for a month. At the end of the experiment, full anaesthesia was induced in all rats using ether inhalation and ECG was recorded. Blood samples were collected then rats were sacrificed and their heart were dissected out and processed for biochemical and histopathological studies. Untreated diabetic rats showed abnormal ECG pattern, elevation of serum cardiac enzymes, decrease EPO levels, downregulation of P-Akt, P-JAK2 and pMAPK pathways, abnormal histological structure of the heart and increase immunostaining intensity of P53 and TNF α in the cardiomyocytes. Dapa in a dose dependent manner attenuated the alterations in the previously mentioned parameters. Conclusion: The cardioprotective effect of Dapa could be mediated by increasing EPO levels and activation of P-Akt, P-JAK2 and pMAPK signalling cascades which in turn decrease apoptosis.

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CaMKII Inhibition is a Novel Therapeutic Strategy to Prevent Diabetic Cardiomyopathy

Frontiers in Pharmacology ◽

10.3389/fphar.2021.695401 ◽

2021 ◽

Vol 12 ◽

Author(s):

Christopher R. Veitch ◽

Amelia S. Power ◽

Jeffrey R. Erickson

Keyword(s):

Diabetic Cardiomyopathy ◽

Cardiac Dysfunction ◽

Therapeutic Strategy ◽

Complex Disease ◽

Positive Impact ◽

Critical Examination ◽

Diabetic Patients ◽

Protective Effects ◽

Camkii Activation ◽

Novel Therapeutic

Increasing prevalence of diabetes mellitus worldwide has pushed the complex disease state to the foreground of biomedical research, especially concerning its multifaceted impacts on the cardiovascular system. Current therapies for diabetic cardiomyopathy have had a positive impact, but with diabetic patients still suffering from a significantly greater burden of cardiac pathology compared to the general population, the need for novel therapeutic approaches is great. A new therapeutic target, calcium/calmodulin-dependent kinase II (CaMKII), has emerged as a potential treatment option for preventing cardiac dysfunction in the setting of diabetes. Within the last 10 years, new evidence has emerged describing the pathophysiological consequences of CaMKII activation in the diabetic heart, the mechanisms that underlie persistent CaMKII activation, and the protective effects of CaMKII inhibition to prevent diabetic cardiomyopathy. This review will examine recent evidence tying cardiac dysfunction in diabetes to CaMKII activation. It will then discuss the current understanding of the mechanisms by which CaMKII activity is enhanced during diabetes. Finally, it will examine the benefits of CaMKII inhibition to treat diabetic cardiomyopathy, including contractile dysfunction, heart failure with preserved ejection fraction, and arrhythmogenesis. We intend this review to serve as a critical examination of CaMKII inhibition as a therapeutic strategy, including potential drawbacks of this approach.

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Abstract 16563: FOXO1 Induces Cardiomyocyte-KLF5, Which Drives Oxidative Stress and Diabetic Cardiomyopathy

Circulation ◽

10.1161/circ.142.suppl_3.16563 ◽

2020 ◽

Vol 142 (Suppl_3) ◽

Author(s):

Ioannis D Kyriazis ◽

Matthew K Hoffman ◽

Lea Gaignebet ◽

Anna Maria Lucchese ◽

Chao Wang ◽

...

Keyword(s):

Oxidative Stress ◽

Diabetic Cardiomyopathy ◽

Cardiac Dysfunction ◽

Constitutive Expression ◽

Diabetic Patients ◽

Mrna Levels ◽

Dependent Manner ◽

Lipid Species ◽

Ceramide Accumulation ◽

Klf5 Expression

Introduction: Cardiomyopathy in type 1 diabetes (T1D) is accompanied by impaired mitochondrial function, oxidative stress and lipotoxicity. We showed that cardiomyocyte (CM) Krüppel-like factor 5 (KLF5) is increased in streptozotocin-induced T1D and induces Peroxisome Proliferator Activated Receptor (PPAR)α in mice. Hypothesis: KLF5 upregulation by FOXO1 induces diabetic cardiomyopathy (DbCM). Methods and Results: Analyses in CM from diabetic patients showed higher KLF5 mRNA levels compared to non-diabetic individuals. In vitro mechanistic and in vivo analyses in αMHC- Foxo1 -/- mice revealed that FOXO1 stimulates KLF5 expression via direct promoter binding. Genetic inhibition of CM FOXO1 alleviated DbCM. Additionally, AAV-mediated CM-specific KLF5 overexpression in C57Bl/6 (WT) mice induced cardiac dysfunction. Mice with CM-specific KLF5 constitutive expression (αMHC-rtTA- Klf5 ), which we generated, recapitulated cardiomyopathy without T1D. Moreover, Pparα -/- mice with T1D, had higher CM-KLF5 levels and developed DbCM, suggesting that KLF5-driven DbCM is PPARα-independent. Additionally, CM-KLF5 induced oxidative stress through increased NADPH oxidase (NOX)4 expression and lower mitochondria abundance. Conversely, KLF5 inhibition prevented NOX4 upregulation and superoxide formation. Furthermore, CM-KLF5 promoted NOX4 expression via direct promoter binding. Antioxidant treatment in diabetic WT and αMHC-rtTA- Klf5 mice alleviated cardiac dysfunction partially, suggesting other pathways that contribute in KLF5-induced DbCM. For that, we performed cardiac lipidome analysis where we found clustering of αMHC-rtTA- Klf5 with diabetic WT mice. Of note, KLF5 inhibition in diabetic mice resulted in similar lipidome with non-diabetic WT mice. Individual lipid species analysis showed increased ceramide accumulation in diabetic WT and αMHC-rtTA- Klf5 mice that was reversed upon KLF5 inhibition. Thus, CM-KLF5 activation correlates with cardiac ceramide accumulation, that has been associated with cardiac lipotoxicity. Conclusions: In conclusion, T1D stimulates FOXO1, which induces CM-KLF5 expression that leads to oxidative stress and DbCM in a non-PPARα-dependent manner, as well as to cardiac ceramide accumulation.

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Nampt Potentiates Antioxidant Defense in Diabetic Cardiomyopathy

Circulation Research ◽

10.1161/circresaha.120.317943 ◽

2021 ◽

Author(s):

Shin-ichi Oka ◽

Jaemin Byun ◽

Chun-yang Huang ◽

Nobushige Imai ◽

Guersom Eduardo Ralda ◽

...

Keyword(s):

Oxidative Stress ◽

Diastolic Dysfunction ◽

Diabetic Cardiomyopathy ◽

Dependent Manner ◽

Nad Kinase ◽

Nicotinamide Phosphoribosyltransferase ◽

Thioredoxin 1 ◽

Rate Limiting ◽

Cultured Cardiomyocytes

Rationale: Diabetic cardiomyopathy is accompanied by increased production of NADH, predominantly through oxidation of fatty acids and consequent increases in oxidative stress. The role of nicotinamide phosphoribosyltransferase (Nampt), the rate-limiting enzyme of the salvage pathway of NAD + synthesis, in the development of diabetic cardiomyopathy is poorly understood. Objective: We investigated the role of endogenous and exogenous Nampt during the development of diabetic cardiomyopathy in response to high fat diet (HFD) consumption and in the context of oxidative stress. Methods and Results: HFD consumption upregulated endogenous Nampt, and HFD-induced cardiac diastolic dysfunction, fibrosis, apoptosis and pro-inflammatory signaling were alleviated in transgenic mice with cardiac-specific overexpression of Nampt. The alleviation of diastolic dysfunction observed in these mice was abolished by inhibition of NADP(H) production via NAD kinase (NADK) inhibition. Nampt overexpression decreased the GSSG/GSH ratio, oxidation of thioredoxin 1 (Trx1) targets, dityrosine, and the accumulation of toxic lipids, including ceramides and diglycerides, in the presence of HFD consumption. Nampt overexpression upregulated not only NAD + but also NADP + and NADPH in the heart and in cultured cardiomyocytes, which in turn stimulated the GSH and Trx1 systems and alleviated oxidative stress in the heart induced by HFD consumption. In cultured cardiomyocytes, Nampt-induced upregulation of NADPH was abolished in the presence of NADK knockdown, whereas that of NAD + was not. Nampt overexpression attenuated H 2 O 2 -induced oxidative inhibition of Prdx1 and mTOR in an NADK-dependent manner in cultured cardiomyocytes. Nampt overexpression also attenuated H 2 O 2 -induced cell death, an effect that was partly abolished by inhibition of NADK, Trx1 or GSH synthesis. In contrast, oxidative stress and the development of diabetic cardiomyopathy in response to HFD consumption were exacerbated in Nampt +/- mice. Conclusions: Nampt-mediated production of NAD + protects against oxidative stress in part through the NADPH-dependent reducing system, thereby alleviating the development of diabetic cardiomyopathy in response to HFD consumption.

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Abstract 305: Carvacrol Attenuates Diabetic Cardiomyopathy by Enhancing PI3K/AKT Pathway in STZ-induced Type 1 Diabetic C57BL/6J Mice

Circulation Research ◽

10.1161/res.119.suppl_1.305 ◽

2016 ◽

Vol 119 (suppl_1) ◽

Author(s):

Ning Hou ◽

Yunpei Mai ◽

Wenliang Chen ◽

Faqian Li ◽

Jiandong Luo

Keyword(s):

Western Blotting ◽

Diabetic Cardiomyopathy ◽

Plasma Concentrations ◽

Akt Pathway ◽

Dependent Manner ◽

Diabetic Mice ◽

Diabetes Group ◽

Protein Levels ◽

Group I

Background: Carvacrol (CAR), a monoterpenic phenol that occurs in many essential oils of the family Labiatae including Origanum , Satureja , Thymbra , Thymus , and Corydothymus species, possess a wide variety of pharmacological properties including antioxidant and anti-inflammatory potential. This present study was designed to investigate the cardiac protective effect of CAR on diabetic cardiomyopathy in STZ-induced type 1 diabetic mice and explore its potential molecular mechanism. Methods: Type 1 diabetes was induced by the intraperitoneal injection of streptozocin (STZ) to male mice at dose of 45 mg/kg body weight (BW). The diabetic animals were divided into three groups containing eight in each: Group I diabetes, Group II and II injected with CAR at 10 and 20 mg/kg BW respectively once daily for 6 weeks. Age matched male C57 mice were used as normal controls. The plasma concentrations of glucose, total cholesterol (TC) and triglycerides (TG) levels were enzymatically determined using commercial kits. The cardiac function was measured by echocardiography. Protein levels of p-PDK1/t-PDK1, p-AKT/t-AKT, p-GSKα/β/t-GSKα/β were detected by Western blotting. Results: STZ-induced C57BL/6J diabetic mice showed an elevation in serum glucose, TG and TC level. Compared to diabetic mice, administration of CAR resulted in significant decrease ( P <0.05) in plasma glucose level in a dose dependent manner, but did not attenuate elevation in TG and TC levels. The abnormal diastolic function in type 1 diabetic mice was significantly reversed by CAR administration. Furthermore, western blotting showed that the expression of p-PDK1, p-AKT and p-GSKα/β were lower in diabetic hearts than C57 hearts while total PDK1, AKT and GSK α/β protein levels were no difference among groups. CAR administration attenuated these decreases in protein phosphorylation. These findings indicate that the impaired PI3K/AKT pathway induced by STZ in diabetic heart can be restored by CAR. Conclusion: Carvacrol has antidiabetic property and can be potentially used to prevent hyperglycemia and diabetic cardiomyopathy.

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