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

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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KLF5 Is Induced by FOXO1 and Causes Oxidative Stress and Diabetic Cardiomyopathy

Circulation Research ◽

10.1161/circresaha.120.316738 ◽

2020 ◽

Author(s):

Ioannis Kyriazis ◽

Matthew Hoffman ◽

Lea Gaignebet ◽

Anna Maria Lucchese ◽

Eftychia Markopoulou ◽

...

Keyword(s):

Oxidative Stress ◽

Diabetic Cardiomyopathy ◽

Major Complication ◽

Peroxisome Proliferator ◽

Mrna Levels ◽

Diabetic Mice ◽

Peroxisome Proliferator Activated Receptor ◽

Patients With Diabetes ◽

Ceramide Accumulation ◽

Klf5 Expression

Rationale: Diabetic cardiomyopathy (DbCM) is a major complication in type-1 diabetes (T1D), accompanied by altered cardiac energetics, impaired mitochondrial function and oxidative stress. Previous studies indicate that T1D is associated with increased cardiac expression of Krüppel-like factor-5 (KLF5) and Peroxisome Proliferator Activated Receptor (PPAR)α that regulate cardiac lipid metabolism. Objective: In this study, we investigated the involvement of KLF5 in DbCM and its transcriptional regulation. Methods and Results: KLF5 mRNA levels were assessed in isolated cardiomyocytes from cardiovascular patients with diabetes and was higher compared with non-diabetic individuals. Analyses in human cells and diabetic mice with cardiomyocyte-specific FOXO1 deletion showed that FOXO1 bound directly on the KLF5 promoter and increased KLF5 expression. Diabetic mice with cardiomyocyte-specific FOXO1 deletion had lower cardiac KLF5 expression and were protected from DbCM. Genetic, pharmacologic gain and loss of KLF5 function approaches and AAV-mediated Klf5 delivery in mice showed that KLF5 induces DbCM. Accordingly, the protective effect of cardiomyocyte FOXO1 ablation in DbCM was abolished when KLF5 expression was rescued. Similarly, constitutive cardiomyocyte-specific KLF5 overexpression caused cardiac dysfunction. KLF5 caused oxidative stress via direct binding on NADPH oxidase (NOX)4 promoter and induction of NOX4 expression. This was accompanied by accumulation of cardiac ceramides. Pharmacologic or genetic KLF5 inhibition alleviated superoxide formation, prevented ceramide accumulation and improved cardiac function in diabetic mice. Conclusions: Diabetes-mediated activation of cardiomyocyte FOXO1 increases KLF5 expression, which stimulates NOX4 expression, ceramide accumulation and causes DbCM.

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GDF11 alleviates pathological myocardial remodeling in diabetic cardiomyopathy through SIRT1-dependent regulation of oxidative stress and apoptosis

10.21203/rs.3.rs-357210/v1 ◽

2021 ◽

Author(s):

Hanzhao Zhu ◽

Liyun Zhang ◽

Mengen Zhai ◽

Lin Xia ◽

Yu Cao ◽

...

Keyword(s):

Oxidative Stress ◽

Signaling Pathway ◽

Diabetic Cardiomyopathy ◽

Cardiac Dysfunction ◽

Transforming Growth Factor ◽

Interstitial Fibrosis ◽

Sirtuin 1 ◽

H9c2 Cell ◽

Diabetic Patients ◽

Intramyocardial Injection

Abstract Background Diabetic cardiomyopathy (DCM) is characterized by cardiac dysfunction and cardiomyocyte injury, which induced by metabolic disorder. Nowadays, there is still a lack of drugs for the treatment of DCM. Growth differentiation factor 11 (GDF11) is a novel member of the transforming growth factor β superfamily that alleviates cardiac hypertrophy, myocardial infarction, and vascular injury by regulating oxidative stress, inflammation, and cell survival. However, the roles and underlying mechanisms of GDF11 in DCM remain largely unknown. Methods In this study, we sought to determine whether GDF11 could prevent DCM. The mouse model of diabetes was established by administering a high-fat diet and intraperitoneal injecting streptozotocin. After that, intramyocardial injection of an adeno-associated virus carrying GDF11 gene was used to achieve myocardium-specific overexpression. Results Our data showed that GDF11 overexpression remarkably improved cardiac dysfunction and interstitial fibrosis by reducing the levels of reactive oxygen species and protecting against cardiomyocyte loss. Mechanistically, decreased sirtuin 1 (SIRT1) expression was observed in diabetic mice, which was significantly increased after GDF11 overexpression. To further explore how SIRT1 mediates the role of GDF11, the selective inhibitor EX527 was used to block SIRT1 signaling pathway, which abolished the protective effects of GDF11 against DCM. In vitro studies confirmed that GDF11 protected against H9c2 cell injury in high glucose and palmitate by attenuating oxidative injury and apoptosis, and these effects were also eliminated by SIRT1 depletion. Conclusion Our results demonstrated for the first time that GDF11 protected against DCM by regulating SIRT1 signaling pathway, and GDF11 had the potential to become a novel target for reversing cardiac dysfunction in diabetic patients.

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Human Proximal Tubule Epithelial Cells (HK-2) as a Sensitive In Vitro System for Ochratoxin A Induced Oxidative Stress

Toxins ◽

10.3390/toxins13110787 ◽

2021 ◽

Vol 13 (11) ◽

pp. 787

Author(s):

Enrique García-Pérez ◽

Dojin Ryu ◽

Hwa-Young Kim ◽

Hae Dun Kim ◽

Hyun Jung Lee

Keyword(s):

Oxidative Stress ◽

Ochratoxin A ◽

Cell Lines ◽

Time Dependent ◽

Mrna Levels ◽

Dependent Manner ◽

In Vitro System ◽

Glutathione Peroxidase 1 ◽

Glucose 6 Phosphate Dehydrogenase

Ochratoxin A (OTA) is a mycotoxin that is potentially carcinogenic to humans. Although its mechanism remains unclear, oxidative stress has been recognized as a plausible cause for the potent renal carcinogenicity observed in experimental animals. The effect of OTA on oxidative stress parameters in two cell lines of LLC-PK1 and HK-2 derived from the kidneys of pig and human, respectively, were investigated and compared. We found that the cytotoxicity of OTA on LLC-PK1 and HK-2 cells was dose- and time-dependent in both cell lines. Furthermore, increased intracellular reactive oxygen species (ROS) induced by OTA in both cell lines were observed in a time-dependent manner. Glutathione (GSH) was depleted by OTA at >48 h in HK-2 but not in LLC-PK1 cells. While the mRNA levels of glucose-6-phosphate dehydrogenase (G6PD) and glutathione peroxidase 1 (GPX1) in LLC-PK1 were down-regulated by 0.67- and 0.66-fold, respectively, those of catalase (CAT), glutathione reductase (GSR), and superoxide dismutase 1 (SOD) in HK-2 were up-regulated by 2.20-, 2.24-, and 2.75-fold, respectively, after 72 h exposure to OTA. Based on these results, we conclude that HK-2 cells are more sensitive to OTA-mediated toxicity than LLC-PK1, and OTA can cause a significant oxidative stress in HK-2 as indicated by changes in the parameter evaluated.

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Kir6.1 improves cardiac dysfunction in diabetic cardiomyopathy via the AKT-Foxo1 signaling pathway

10.21203/rs.3.rs-33214/v1 ◽

2020 ◽

Author(s):

Jinxin Wang ◽

Jing Bai ◽

Peng Duan ◽

Hao Wang ◽

Yang Li ◽

...

Keyword(s):

Cardiac Function ◽

Signaling Pathway ◽

Diabetic Cardiomyopathy ◽

Cardiac Dysfunction ◽

Diabetic Patients ◽

Protein Levels ◽

Inwardly Rectifying Potassium Channel ◽

Transmission Electron ◽

Hematoxylin And Eosin ◽

And Function

Abstract Background: Diabetic cardiomyopathy (DCM) severely impairs the health of diabetic patients. Previous studies have shown that the expression of inwardly rectifying potassium channel 6.1 (Kir6.1) in heart mitochondria is significantly reduced in type 1 diabetes. However, whether its expression and function are changed and what role it plays in type 2 DCM have not been reported. This study investigated the role and mechanism of Kir6.1 in DCM.Methods: The cardiac function in mice was analyzed by echocardiography, ELISA, hematoxylin and eosin staining, TUNEL and transmission electron microscopy. The mitochondrial function in cardiomyocytes was measured by the oxygen consumption rate and the mitochondrial membrane potential (ΔΨm). Kir6.1 expression at the mRNA and protein levels was analyzed by quantitative real-time PCR and western blotting (WB), respectively. The protein expression of t-AKT, p-AKT, t-Foxo1, and p-Foxo1 was analyzed by WB.Results: We found that the cardiac function and the Kir6.1 expression in DCM mice were decreased. Kir6.1 overexpression improved cardiac dysfunction and upregulated the phosphorylation of AKT and Foxo1 in the DCM mouse model. Furthermore, Kir6.1 overexpression also improved cardiomyocyte dysfunction and upregulated the phosphorylation of AKT and Foxo1 in cardiomyocytes with insulin resistance. In contrast, cardiac-specific Kir6.1 knockout aggravated the cardiac dysfunction and downregulated the phosphorylation of AKT and Foxo1 in DCM mice. Furthermore, Foxo1 activation downregulated the expression of Kir6.1 and decreased the ΔΨm in cardiomyocytes. In contrast, Foxo1 inactivation upregulated the expression of Kir6.1 and increased the ΔΨm in cardiomyocytes. Chromatin immunoprecipitation assay demonstrated that the Kir6.1 promoter region contains a functional Foxo1-binding site .Conclusions: Kir6.1 improves cardiac dysfunction in DCM, probably through the AKT-Foxo1 signaling pathway. Moreover, the crosstalk between Kir6.1 and the AKT-Foxo1 signaling pathway may provide new strategies for reversing the defective signaling in DCM.

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GW27-e1129 RSVA314 attenuates cardiac dysfunction, oxidative stress, and inflammatory in diabetic cardiomyopathy

Journal of the American College of Cardiology ◽

10.1016/j.jacc.2016.07.150 ◽

2016 ◽

Vol 68 (16) ◽

pp. C40-C41

Author(s):

Gan Shouyi ◽

Hui Yu ◽

Hong-xia Huang ◽

Bing Li ◽

Ling-Yong Zeng ◽

...

Keyword(s):

Oxidative Stress ◽

Diabetic Cardiomyopathy ◽

Cardiac Dysfunction

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CTRP3 attenuates cardiac dysfunction, inflammation, oxidative stress and cell death in diabetic cardiomyopathy in rats

Diabetologia ◽

10.1007/s00125-017-4232-4 ◽

2017 ◽

Vol 60 (6) ◽

pp. 1126-1137 ◽

Cited By ~ 63

Author(s):

Zhen-Guo Ma ◽

Yu-Pei Yuan ◽

Si-Chi Xu ◽

Wen-Ying Wei ◽

Chun-Ru Xu ◽

...

Keyword(s):

Oxidative Stress ◽

Cell Death ◽

Diabetic Cardiomyopathy ◽

Cardiac Dysfunction

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MET18 Deficiency Increases the Sensitivity of Yeast to Oxidative Stress and Shortens Replicative Lifespan by Inhibiting Catalase Activity

BioMed Research International ◽

10.1155/2017/7587395 ◽

2017 ◽

Vol 2017 ◽

pp. 1-8 ◽

Cited By ~ 1

Author(s):

Ya-qin Chen ◽

Xin-guang Liu ◽

Wei Zhao ◽

Hongjing Cui ◽

Jie Ruan ◽

...

Keyword(s):

Oxidative Stress ◽

Catalase Activity ◽

Molecular Mechanisms ◽

Cumene Hydroperoxide ◽

Yeast Cells ◽

Mrna Levels ◽

Dependent Manner ◽

Replicative Capacity ◽

Replicative Lifespan ◽

Increased Sensitivity

Yeast MET18, a subunit of the cytosolic iron-sulfur (Fe/S) protein assembly (CIA) machinery which is responsible for the maturation of Fe/S proteins, has been reported to participate in the oxidative stress response. However, the underlying molecular mechanisms remain unclear. In this study, we constructed a MET18/met18Δ heterozygous mutant yeast strain and found that MET18 deficiency in yeast cells impaired oxidative stress resistance as evidenced by increased sensitivity to hydrogen peroxide (H2O2) and cumene hydroperoxide (CHP). Mechanistically, the mRNA levels of catalase A (CTA1) and catalase T (CTT1) as well as the total catalase activity were significantly reduced in MET18-deficient cells. In contrast, overexpression of CTT1 or CTA1 in MET18-deficient cells significantly increased the intracellular catalase activity and enhanced the resistance ability against H2O2 and CHP. In addition, MET18 deficiency diminished the replicative capacity of yeast cells as evidenced by the shortened replicative lifespan, which can be restored by CTT1 overexpression, but not by CTA1, in the MET18-deficient cells. These results suggest that MET18, in a catalase-dependent manner, plays an essential role in enhancing the resistance of yeast cells to oxidative stress and increasing the replicative capacity of yeast cells.

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Oxidative Stress and Mitogen-Activated Protein Kinase Pathways Involved in Cadmium-Induced BRL 3A Cell Apoptosis

Oxidative Medicine and Cellular Longevity ◽

10.1155/2013/516051 ◽

2013 ◽

Vol 2013 ◽

pp. 1-12 ◽

Cited By ~ 23

Author(s):

Zhang Yiran ◽

Jiang Chenyang ◽

Wang Jiajing ◽

Yuan Yan ◽

Gu Jianhong ◽

...

Keyword(s):

Oxidative Stress ◽

Mitogen Activated Protein Kinase ◽

Ros Generation ◽

Mrna Levels ◽

Dependent Manner ◽

Nuclear Condensation ◽

Concentration Dependent Manner ◽

P38 Inhibitor ◽

Mapk Pathways ◽

Induced Apoptosis

In this study, BRL 3A cells were treated with different Cd concentrations (0, 10, 20, and 40 μmol/L) for 12 h and preincubated with or without N-acetyl-L-cysteine (NAC) (2 mmol/L) for 30 min, and cells were treated with Cd (0 and 20 μmol/L), pretreated with p38 inhibitor (SB203580), JNK (c-Jun NH2-terminal kinases) inhibitor (SP600125), and extracellular signal-regulated kinase (ERK) inhibitor (U0126) for 30 min, and then treated with 20 μmol/L Cd for 12 h. Cd decreased cell viability, SOD, and GSH-Px activity in a concentration-dependent manner. Increased MDA level, ROS generation, nuclear condensation, shrinkage, and fragmentation in cell morphology were inhibited by NAC. Cd-induced apoptosis was attenuated by pretreatment with SB203580, SP600125, and U0126. The results of western blot showed that NAC preincubation affected Cd-activated MAPK pathways, p38 and ERK phosphorylation. Cd treatment elevated the mRNA levels of Bax and decreased the mRNA levels of Bcl-2, respectively. The same effect was found in their protein expression levels. These results suggest that oxidative stress and MAPK pathways participate in Cd-induced apoptosis and that the balance between pro- and antiapoptotic genes (Bax and Bcl-2) is important in Cd-induced apoptosis.

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Role of catecholamines in the pathogenesis of diabetic cardiomyopathy

Canadian Journal of Physiology and Pharmacology ◽

10.1139/cjpp-2019-0044 ◽

2019 ◽

Vol 97 (9) ◽

pp. 815-819 ◽

Cited By ~ 1

Author(s):

Naranjan S. Dhalla ◽

Pallab K. Ganguly ◽

Sukhwinder K. Bhullar ◽

Paramjit S. Tappia

Keyword(s):

Oxidative Stress ◽

Gene Expression ◽

Nervous System ◽

Sympathetic Nervous System ◽

Diabetic Cardiomyopathy ◽

Cardiac Dysfunction ◽

Oxidation Products ◽

Sympathetic Nervous ◽

Myocardial Gene Expression

Although the sympathetic nervous system plays an important role in the regulation of cardiac function, the overactivation of the sympathetic nervous system under stressful conditions including diabetes has been shown to result in the excessive production of circulating catecholamines as well as an increase in the myocardial concentration of catecholamines. In this brief review, we provide some evidence to suggest that the oxidation products of catecholamines such as aminochrome and oxyradicals, lead to metabolic derangements, Ca2+-handling abnormalities, increase in the availability of intracellular free Ca2+, as well as activation of proteases and changes in myocardial gene expression. These alterations due to elevated levels of circulatory catecholamines are associated with oxidative stress, subcellular remodeling, and the development of cardiac dysfunction in chronic diabetes.

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