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Methylglyoxal (MGO) is an endogenous, highly reactive dicarbonyl metabolite generated under hyperglycaemic conditions. MGO plays a role in developing pathophysiological conditions, including diabetic cardiomyopathy. However, the mechanisms involved and the molecular targets of MGO in the heart have not been elucidated. In this work, we studied the exposure-related effects of MGO on cardiac function in an isolated perfused rat heart ex vivo model. The effect of MGO on calcium homeostasis in cardiomyocytes was studied in vitro by the fluorescence indicator of intracellular calcium Fluo-4. We demonstrated that MGO induced cardiac dysfunction, both in contractility and diastolic function. In rat heart, the effects of MGO treatment were significantly limited by aminoguanidine, a scavenger of MGO, ruthenium red, a general cation channel blocker, and verapamil, an L-type voltage-dependent calcium channel blocker, demonstrating that this dysfunction involved alteration of calcium regulation. MGO induced a significant concentration-dependent increase of intracellular calcium in neonatal rat cardiomyocytes, which was limited by aminoguanidine and verapamil. These results suggest that the functionality of various calcium channels is altered by MGO, particularly the L-type calcium channel, thus explaining its cardiac toxicity. Therefore, MGO could participate in the development of diabetic cardiomyopathy through its impact on calcium homeostasis in cardiac cells.
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Calcio , Miocitos Cardíacos , Piruvaldehído , Ratas Wistar , Animales , Piruvaldehído/toxicidad , Ratas , Calcio/metabolismo , Miocitos Cardíacos/metabolismo , Miocitos Cardíacos/efectos de los fármacos , Masculino , Guanidinas/farmacología , Canales de Calcio Tipo L/metabolismo , Corazón/efectos de los fármacos , Miocardio/metabolismo , Verapamilo/farmacología , Contracción Miocárdica/efectos de los fármacosRESUMEN
BACKGROUND: Chronic overconsumption of lipids followed by their excessive accumulation in the heart leads to cardiomyopathy. The cause of lipid-induced cardiomyopathy involves a pivotal role for the proton-pump vacuolar-type H+-ATPase (v-ATPase), which acidifies endosomes, and for lipid-transporter CD36, which is stored in acidified endosomes. During lipid overexposure, an increased influx of lipids into cardiomyocytes is sensed by v-ATPase, which then disassembles, causing endosomal de-acidification and expulsion of stored CD36 from the endosomes toward the sarcolemma. Once at the sarcolemma, CD36 not only increases lipid uptake but also interacts with inflammatory receptor TLR4 (Toll-like receptor 4), together resulting in lipid-induced insulin resistance, inflammation, fibrosis, and cardiac dysfunction. Strategies inducing v-ATPase reassembly, that is, to achieve CD36 reinternalization, may correct these maladaptive alterations. For this, we used NAD+ (nicotinamide adenine dinucleotide)-precursor nicotinamide mononucleotide (NMN), inducing v-ATPase reassembly by stimulating glycolytic enzymes to bind to v-ATPase. METHODS: Rats/mice on cardiomyopathy-inducing high-fat diets were supplemented with NMN and for comparison with a cocktail of lysine/leucine/arginine (mTORC1 [mechanistic target of rapamycin complex 1]-mediated v-ATPase reassembly). We used the following methods: RNA sequencing, mRNA/protein expression analysis, immunofluorescence microscopy, (co)immunoprecipitation/proximity ligation assay (v-ATPase assembly), myocellular uptake of [3H]chloroquine (endosomal pH), and [14C]palmitate, targeted lipidomics, and echocardiography. To confirm the involvement of v-ATPase in the beneficial effects of both supplementations, mTORC1/v-ATPase inhibitors (rapamycin/bafilomycin A1) were administered. Additionally, 2 heart-specific v-ATPase-knockout mouse models (subunits V1G1/V0d2) were subjected to these measurements. Mechanisms were confirmed in pharmacologically/genetically manipulated cardiomyocyte models of lipid overload. RESULTS: NMN successfully preserved endosomal acidification during myocardial lipid overload by maintaining v-ATPase activity and subsequently prevented CD36-mediated lipid accumulation, CD36-TLR4 interaction toward inflammation, fibrosis, cardiac dysfunction, and whole-body insulin resistance. Lipidomics revealed C18:1-enriched diacylglycerols as lipid class prominently increased by high-fat diet and subsequently reversed/preserved by lysine/leucine/arginine/NMN treatment. Studies with mTORC1/v-ATPase inhibitors and heart-specific v-ATPase-knockout mice further confirmed the pivotal roles of v-ATPase in these beneficial actions. CONCLUSION: NMN preserves heart function during lipid overload by preventing v-ATPase disassembly.
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Cardiomiopatías , Resistencia a la Insulina , Animales , Ratones , Ratas , Adenosina Trifosfatasas , Arginina , Cardiomiopatías/inducido químicamente , Cardiomiopatías/prevención & control , Antígenos CD36/genética , Fibrosis , Inflamación , Leucina , Lípidos , Lisina , Diana Mecanicista del Complejo 1 de la Rapamicina , Miocitos Cardíacos , Mononucleótido de Nicotinamida , Receptor Toll-Like 4/genéticaRESUMEN
BACKGRUOUND: Diabetes-induced cardiac fibrosis is one of the main mechanisms of diabetic cardiomyopathy. As a common histone methyltransferase, enhancer of zeste homolog 2 (EZH2) has been implicated in fibrosis progression in multiple organs. However, the mechanism of EZH2 in diabetic myocardial fibrosis has not been clarified. METHODS: In the current study, rat and mouse diabetic model were established, the left ventricular function of rat and mouse were evaluated by echocardiography and the fibrosis of rat ventricle was evaluated by Masson staining. Primary rat ventricular fibroblasts were cultured and stimulated with high glucose (HG) in vitro. The expression of histone H3 lysine 27 (H3K27) trimethylation, EZH2, and myocardial fibrosis proteins were assayed. RESULTS: In STZ-induced diabetic ventricular tissues and HG-induced primary ventricular fibroblasts in vitro, H3K27 trimethylation was increased and the phosphorylation of EZH2 was reduced. Inhibition of EZH2 with GSK126 suppressed the activation, differentiation, and migration of cardiac fibroblasts as well as the overexpression of the fibrotic proteins induced by HG. Mechanical study demonstrated that HG reduced phosphorylation of EZH2 on Thr311 by inactivating AMP-activated protein kinase (AMPK), which transcriptionally inhibited peroxisome proliferator-activated receptor γ (PPAR-γ) expression to promote the fibroblasts activation and differentiation. CONCLUSION: Our data revealed an AMPK/EZH2/PPAR-γ signal pathway is involved in HG-induced cardiac fibrosis.
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Proteínas Quinasas Activadas por AMP , Diabetes Mellitus Experimental , Cardiomiopatías Diabéticas , Proteína Potenciadora del Homólogo Zeste 2 , Fibrosis , Miocardio , PPAR gamma , Transducción de Señal , Animales , Proteína Potenciadora del Homólogo Zeste 2/metabolismo , PPAR gamma/metabolismo , Ratones , Ratas , Cardiomiopatías Diabéticas/metabolismo , Cardiomiopatías Diabéticas/etiología , Diabetes Mellitus Experimental/metabolismo , Diabetes Mellitus Experimental/complicaciones , Masculino , Proteínas Quinasas Activadas por AMP/metabolismo , Miocardio/patología , Miocardio/metabolismo , Ratas Sprague-Dawley , Fibroblastos/metabolismo , Ratones Endogámicos C57BL , Células Cultivadas , FosforilaciónRESUMEN
Insulin resistance has been regarded as a hallmark of diabetes heart disease (DHD). Numerous studies have shown that insulin resistance can affect blood circulation and myocardium, which indirectly cause cardiac hypertrophy and ventricular remodeling, participating in the pathogenesis of DHD. Meanwhile, hyperinsulinemia, hyperglycemia, and hyperlipidemia associated with insulin resistance can directly impair the metabolism and function of the heart. Targeting insulin resistance is a potential therapeutic strategy for the prevention of DHD. Currently, the role of insulin resistance in the pathogenic development of DHD is still under active research, as the pathological roles involved are complex and not yet fully understood, and the related therapeutic approaches are not well developed. In this review, we describe insulin resistance and add recent advances in the major pathological and physiological changes and underlying mechanisms by which insulin resistance leads to myocardial remodeling and dysfunction in the diabetic heart, including exosomal dysfunction, ferroptosis, and epigenetic factors. In addition, we discuss potential therapeutic approaches to improve insulin resistance and accelerate the development of cardiovascular protection drugs.
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Diabetes Mellitus , Cardiopatías , Resistencia a la Insulina , Humanos , Resistencia a la Insulina/fisiología , Diabetes Mellitus/metabolismo , Miocardio/metabolismo , Corazón , Cardiopatías/etiología , Cardiopatías/metabolismoRESUMEN
Diabetic cardiomyopathy (DCM) is a significant cause of heart failure in patients with diabetes, and its pathogenesis is closely related to myocardial mitochondrial injury and functional disability. Studies have shown that the development of diabetic cardiomyopathy is related to disorders in mitochondrial metabolic substrates, changes in mitochondrial dynamics, an imbalance in mitochondrial Ca2+ regulation, defects in the regulation of microRNAs, and mitochondrial oxidative stress. Physical activity may play a role in resistance to the development of diabetic cardiomyopathy by improving myocardial mitochondrial biogenesis, the level of autophagy and dynamic changes in fusion and division; enhancing the ability to cope with oxidative stress; and optimising the metabolic substrates of the myocardium. This paper puts forward a new idea for further understanding the specific mitochondrial mechanism of the occurrence and development of diabetic cardiomyopathy and clarifying the role of exercise-mediated myocardial mitochondrial changes in the prevention and treatment of diabetic cardiomyopathy. This is expected to provide a new theoretical basis for exercise to reduce diabetic cardiomyopathy symptoms.
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Diabetes Mellitus , Cardiomiopatías Diabéticas , Humanos , Cardiomiopatías Diabéticas/metabolismo , Cardiomiopatías Diabéticas/patología , Mitocondrias Cardíacas/metabolismo , Miocardio/metabolismo , Ejercicio Físico , Estrés Oxidativo , Diabetes Mellitus/metabolismoRESUMEN
BACKGROUND: The majority of people with diabetes are susceptible to cardiac dysfunction and heart failure, and conventional drug therapy cannot correct diabetic cardiomyopathy progression. Herein, we assessed the potential role and therapeutic value of USP28 (ubiquitin-specific protease 28) on the metabolic vulnerability of diabetic cardiomyopathy. METHODS: The type 2 diabetes mouse model was established using db/db leptin receptor-deficient mice and high-fat diet/streptozotocin-induced mice. Cardiac-specific knockout of USP28 in the db/db background mice was generated by crossbreeding db/m and Myh6-Cre+/USP28fl/fl mice. Recombinant adeno-associated virus serotype 9 carrying USP28 under cardiac troponin T promoter was injected into db/db mice. High glucose plus palmitic acid-incubated neonatal rat ventricular myocytes and human induced pluripotent stem cell-derived cardiomyocytes were used to imitate diabetic cardiomyopathy in vitro. The molecular mechanism was explored through RNA sequencing, immunoprecipitation and mass spectrometry analysis, protein pull-down, chromatin immunoprecipitation sequencing, and chromatin immunoprecipitation assay. RESULTS: Microarray profiling of the UPS (ubiquitin-proteasome system) on the basis of db/db mouse hearts and diabetic patients' hearts demonstrated that the diabetic ventricle presented a significant reduction in USP28 expression. Diabetic Myh6-Cre+/USP28fl/fl mice exhibited more severe progressive cardiac dysfunction, lipid accumulation, and mitochondrial disarrangement, compared with their controls. On the other hand, USP28 overexpression improved systolic and diastolic dysfunction and ameliorated cardiac hypertrophy and fibrosis in the diabetic heart. Adeno-associated virus serotype 9-USP28 diabetic mice also exhibited less lipid storage, reduced reactive oxygen species formation, and mitochondrial impairment in heart tissues than adeno-associated virus serotype 9-null diabetic mice. As a result, USP28 overexpression attenuated cardiac remodeling and dysfunction, lipid accumulation, and mitochondrial impairment in high-fat diet/streptozotocin-induced type 2 diabetes mice. These results were also confirmed in neonatal rat ventricular myocytes and human induced pluripotent stem cell-derived cardiomyocytes. RNA sequencing, immunoprecipitation and mass spectrometry analysis, chromatin immunoprecipitation assays, chromatin immunoprecipitation sequencing, and protein pull-down assay mechanistically revealed that USP28 directly interacted with PPARα (peroxisome proliferator-activated receptor α), deubiquitinating and stabilizing PPARα (Lys152) to promote Mfn2 (mitofusin 2) transcription, thereby impeding mitochondrial morphofunctional defects. However, such cardioprotective benefits of USP28 were largely abrogated in db/db mice with PPARα deletion and conditional loss-of-function of Mfn2. CONCLUSIONS: Our findings provide a USP28-modulated mitochondria homeostasis mechanism that involves the PPARα-Mfn2 axis in diabetic hearts, suggesting that USP28 activation or adeno-associated virus therapy targeting USP28 represents a potential therapeutic strategy for diabetic cardiomyopathy.
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Diabetes Mellitus Experimental , Diabetes Mellitus Tipo 2 , Cardiomiopatías Diabéticas , Células Madre Pluripotentes Inducidas , Ubiquitina Tiolesterasa , Animales , Humanos , Ratones , Ratas , Diabetes Mellitus Experimental/complicaciones , Diabetes Mellitus Experimental/genética , Diabetes Mellitus Experimental/metabolismo , Diabetes Mellitus Tipo 2/complicaciones , Diabetes Mellitus Tipo 2/genética , Diabetes Mellitus Tipo 2/metabolismo , Cardiomiopatías Diabéticas/metabolismo , Células Madre Pluripotentes Inducidas/metabolismo , Lípidos , Ratones Noqueados , Miocitos Cardíacos/metabolismo , PPAR alfa/metabolismo , Estreptozocina/metabolismo , Estreptozocina/uso terapéutico , Ubiquitina Tiolesterasa/análisis , Ubiquitina Tiolesterasa/metabolismoRESUMEN
BACKGROUND: Diabetes is an important risk factor for heart failure (HF) and is associated with left ventricular (LV) diastolic dysfunction. However, diabetic comorbid conditions, such as nocturnal hypertension, as predictors of diastolic dysfunction are not known in the absence of an HF period. The present study was conducted as the longitudinal examination of the predictive value of nocturnal hypertension profiles on the progression of LV diastolic dysfunction in patients with and without diabetes without HF. METHODS: The subjects (154 diabetes and 268 nondiabetes) in the absence of HF were followed for 36.8±18.2 months. The relationships among the patterns of nocturnal hypertension and the outcome of LV diastolic dysfunction, defined as an increase in E/e'>14, were investigated in the patients with and without diabetes. RESULTS: The interaction effect of the diabetes status and the patterns of nocturnal hypertension on the hazard rate of the occurrence of E/e'>14 was statistically significant (P=0.017). Kaplan-Meier analysis results revealed that patients with diabetes with nondipper (P=0.021 versus dipper) and riser (P=0.006 versus dipper) had a greater risk for a diastolic dysfunction event. Furthermore, multivariable Cox proportional hazards analysis revealed that nondipper (hazard ratio, 4.56 [95% CI, 1.49-13.96]; P=0.007) and riser (hazard ratio, 3.89 [95% CI, 1.31-11.57]; P=0.014) patterns were associated with elevated risk of the outcome of LV diastolic dysfunction. In contrast, no similar significant associations were found in patients without diabetes. CONCLUSIONS: During the absence of HF periods, nocturnal hypertension is an important predictor for the progression of LV diastolic dysfunction in patients with diabetes.
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Diabetes Mellitus , Insuficiencia Cardíaca , Hipertensión , Disfunción Ventricular Izquierda , Humanos , Función Ventricular Izquierda , Estudios Prospectivos , Diabetes Mellitus/epidemiología , Disfunción Ventricular Izquierda/epidemiología , Disfunción Ventricular Izquierda/etiología , Hipertensión/complicaciones , Hipertensión/epidemiología , Diástole , Volumen SistólicoRESUMEN
Diabetic cardiomyopathy(DCM)is a complication of diabetes mellitus.It is characterized by abnormal myocardial cells leading to diastolic and systolic dysfunction,which can eventually lead to heart failure,impair the health of diabetic patients and worsen the poor prognosis.Studies indicated that mitochondrion directly participated in occurrence and development of DCM,involving glucose and lipid metabolic regulation,calcium homeostasis main-tenance,reactive oxygen species(ROS)level and oxidative stress etc.,whose normal functioning is necessary for human health.Mitochondrial dysfunction is closely associated with occurrence and development of DCM.The pres-ent article makes a review on mitochondrial structure and physiological function,dynamics and dysfunction,and role of mitochondrial dysfunction in DCM,and explore new targets for the prevention and treatment of DCM.
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BACKGROUND: Diabetes is associated with cardiovascular complications. microRNAs translocate into subcellular organelles to modify genes involved in diabetic cardiomyopathy. However, functional properties of subcellular AGO2 (Argonaute2), a core member of miRNA machinery, remain elusive. METHODS: We elucidated the function and mechanism of subcellular localized AGO2 on mouse models for diabetes and diabetic cardiomyopathy. Recombinant adeno-associated virus type 9 was used to deliver AGO2 to mice through the tail vein. Cardiac structure and functions were assessed by echocardiography and catheter manometer system. RESULTS: AGO2 was decreased in mitochondria of diabetic cardiomyocytes. Overexpression of mitochondrial AGO2 attenuated diabetes-induced cardiac dysfunction. AGO2 recruited TUFM, a mitochondria translation elongation factor, to activate translation of electron transport chain subunits and decrease reactive oxygen species. Malonylation, a posttranslational modification of AGO2, reduced the importing of AGO2 into mitochondria in diabetic cardiomyopathy. AGO2 malonylation was regulated by a cytoplasmic-localized short isoform of SIRT3 through a previously unknown demalonylase function. CONCLUSIONS: Our findings reveal that the SIRT3-AGO2-CYTB axis links glucotoxicity to cardiac electron transport chain imbalance, providing new mechanistic insights and the basis to develop mitochondria targeting therapies for diabetic cardiomyopathy.
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Diabetes Mellitus , Cardiomiopatías Diabéticas , MicroARNs , Sirtuina 3 , Ratones , Animales , Sirtuina 3/genética , Genes Mitocondriales , Mitocondrias/genética , MicroARNs/genética , Miocitos Cardíacos/metabolismo , Diabetes Mellitus/metabolismoRESUMEN
OBJECTIVE: To examine the protective effect of ginsenoside Rb1 (Rb1), the main component of Renshen (), on cardiomyopathy in db/db mice exposed to chronic intermittent hypoxia (CIH) and explore the potential underlying mechanism of Rb1 in treating diabetic cardiomyopathy (DCM). METHODS: The db/db mice were randomly separated into five groups: normal control group, model group, Rb1 20 mg/kg group, Rb1 40 mg/kg group, and glucagon-like peptide-1 (GLP-1) group. Mice were exposed to air-condition or CIH for 8 weeks, and Rb1 and GLP-1 were administrated before CIH exposure every day. Oral glucose tolerance test (OGTT), intraperitoneal insulin tolerance test (IPITT), total cholesterol (TC), triglyceride (TG), and high-density lipoprotein cholesterol (HDL-C) were detected to evaluate glycolipid metabolism. The level of insulin was detected by a mouse enzyme-linked immunosorbent assay (ELISA). Cardiac function was detected by echocardiography, and myocardial pathology was observed by hematoxylin-eosin and Masson staining. The expression of collagen â and collagen â ¢ was detected by immunohistochemistry. Adenosine monophosphate-activated protein kinase (AMPK)/Nrf2/heme oxygenase-1 (HO-1) signaling pathway was detected by Western blot and immunofluorescence. RESULTS: Rb1 treatment could improve glucose tolerance and the level of cardiac function indexes, and inhibit the level of oxidative stress indexes and the expression of collagen â and collagen â ¢. Moreover, Rb1 treatment enhanced AMPK phosphorylation and increased Nrf2 and HO-1 expression. CONCLUSION: Rb1 treatment alleviated CIH-induced diabetic cardiomyopathy and glycolipid metabolism disorders in db/db mice by inhibiting oxidative stress and regulating the AMPK/Nrf2/HO-1 signaling pathway.
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Diabetes Mellitus , Cardiomiopatías Diabéticas , Insulinas , Ratones , Animales , Adenosina Monofosfato , Cardiomiopatías Diabéticas/tratamiento farmacológico , Cardiomiopatías Diabéticas/genética , Factor 2 Relacionado con NF-E2/genética , Hemo-Oxigenasa 1/genética , Proteínas Quinasas Activadas por AMP/genética , Transducción de Señal , Colágeno Tipo I , ColesterolRESUMEN
BACKGRUOUND: Diabetes mellitus is one of the most common chronic diseases worldwide, and cardiovascular disease is the leading cause of morbidity and mortality in diabetic patients. Diabetic cardiomyopathy (DCM) is a phenomenon characterized by a deterioration in cardiac function and structure, independent of vascular complications. Among many possible causes, the renin-angiotensin-aldosterone system and angiotensin II have been proposed as major drivers of DCM development. In the current study, we aimed to investigate the effects of pharmacological activation of angiotensin-converting enzyme 2 (ACE2) on DCM. METHODS: The ACE2 activator diminazene aceturate (DIZE) was administered intraperitoneally to male db/db mice (8 weeks old) for 8 weeks. Transthoracic echocardiography was used to assess cardiac mass and function in mice. Cardiac structure and fibrotic changes were examined using histology and immunohistochemistry. Gene and protein expression levels were examined using quantitative reverse transcription polymerase chain reaction and Western blotting, respectively. Additionally, RNA sequencing was performed to investigate the underlying mechanisms of the effects of DIZE and identify novel potential therapeutic targets for DCM. RESULTS: Echocardiography revealed that in DCM, the administration of DIZE significantly improved cardiac function as well as reduced cardiac hypertrophy and fibrosis. Transcriptome analysis revealed that DIZE treatment suppresses oxidative stress and several pathways related to cardiac hypertrophy. CONCLUSION: DIZE prevented the diabetes mellitus-mediated structural and functional deterioration of mouse hearts. Our findings suggest that the pharmacological activation of ACE2 could be a novel treatment strategy for DCM.
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Diabetes Mellitus , Cardiomiopatías Diabéticas , Ratones , Masculino , Animales , Peptidil-Dipeptidasa A/genética , Peptidil-Dipeptidasa A/metabolismo , Enzima Convertidora de Angiotensina 2/metabolismo , Cardiomiopatías Diabéticas/tratamiento farmacológico , Estrés Oxidativo , Cardiomegalia , Angiotensinas/metabolismoRESUMEN
Diabetic cardiomyopathy was originally described as the presence of ventricular dysfunction in the absence of coronary artery disease and/or hypertension. It is characterized by diastolic dysfunction and is more prevalent in people with diabetes than originally realized, leading to the suggestion in the field that it simply be referred to as diabetic heart disease. While there are currently no approved therapies for diabetic heart disease, a multitude of studies clearly demonstrate that it is characterized by several disturbances in myocardial energy metabolism. One of the most prominent changes in myocardial energy metabolism in diabetes is a robust impairment in glucose oxidation. Herein we will describe the mechanisms responsible for the diabetes-induced decline in myocardial glucose oxidation, and the pharmacological approaches that have been pursued to correct this metabolic disorder. With surmounting evidence that stimulating myocardial glucose oxidation can alleviate diastolic dysfunction and other pathologies associated with diabetic heart disease, this may also represent a novel strategy for decreasing the prevalence of heart failure with preserved ejection fraction in the diabetic population.
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BACKGROUND: Diabetic heart dysfunction is a common complication of diabetes. Cell death is a core event that leads to diabetic heart dysfunction. However, the time sequence of cell death pathways and the precise time to intervene of particular cell death type remain largely unknown in the diabetic heart. This study aims to identify the particular cell death type that is responsible for diabetic heart dysfunction and to propose a promising therapeutic strategy by intervening in the cell death pathway. METHODS: Type 2 diabetes models were established using db/db leptin receptor-deficient mice and high-fat diet/streptozotocin-induced mice. The type 1 diabetes model was established in streptozotocin-induced mice. Apoptosis and programmed cell necrosis (necroptosis) were detected in diabetic mouse hearts at different ages. G protein-coupled receptor-targeted drug library was searched to identify potential receptors regulating the key cell death pathway. Pharmacological and genetic approaches that modulate the expression of targets were used. Stable cell lines and a homemade phosphorylation antibody were prepared to conduct mechanistic studies. RESULTS: Necroptosis was activated after apoptosis at later stages of diabetes and was functionally responsible for cardiac dysfunction. Cannabinoid receptor 2 (CB2R) was a key regulator of necroptosis. Mechanically, during normal glucose levels, CB2R inhibited S6 kinase-mediated phosphorylation of BACH2 at serine 520, thereby leading to BACH2 translocation to the nucleus, where BACH2 transcriptionally repressed the necroptosis genes Rip1, Rip3, and Mlkl. Under hyperglycemic conditions, high glucose induced CB2R internalization in a ß-arrestin 2-dependent manner; thereafter, MLKL (mixed lineage kinase domain-like), but not receptor-interacting protein kinase 1 or 3, phosphorylated CB2R at serine 352 and promoted CB2R degradation by ubiquitin modification. Cardiac re-expression of CB2R rescued diabetes-induced cardiomyocyte necroptosis and heart dysfunction, whereas cardiac knockout of Bach2 diminished CB2R-mediated beneficial effects. In human diabetic hearts, both CB2R and BACH2 were negatively associated with diabetes-induced myocardial injuries. CONCLUSIONS: CB2R transcriptionally repressed necroptosis through interaction with BACH2; in turn, MLKL formed a negative feedback to phosphorylate CB2R. Our study provides the integrative view of a novel molecular mechanism loop for regulation of necroptosis centered by CB2R, which represents a promising alternative strategy for controlling diabetic heart dysfunction.
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Cardiomiopatías , Diabetes Mellitus Tipo 2 , Lesiones Cardíacas , Ratones , Humanos , Animales , Necroptosis , Diabetes Mellitus Tipo 2/complicaciones , Diabetes Mellitus Tipo 2/genética , Retroalimentación , Estreptozocina , Apoptosis , Necrosis , Receptores de Cannabinoides/metabolismo , Glucosa , Factores de Transcripción con Cremalleras de Leucina de Carácter Básico/metabolismo , Proteína Serina-Treonina Quinasas de Interacción con Receptores/metabolismoRESUMEN
Objective:To observe the intervention mechanism of phlegm-stasis co-treatment for the JNK signaling pathway in the myocardium of diabetes rats.Methods:Totally 50 male SD rats of SPF grade were selected. Diabetes model was established by single intraperitoneal injection of 55 mg/kg streptozotocin (STZ) solution. After continued feeding for 3 weeks, the rats were divided into normal group, model group, alachloramine group, blood stasis removing group, phlegm removing group and phlegm-blood stasis co-treatment group according to random number table method, with 6 rats in each group. Xiaoxianxiong Decoction (4.05 g/kg), Xuefu Zhuyu Decoction (7.02 g/kg), Didang Xianxiong Decoction (8.10 g/kg) were administered to the stomach respectively in the phlegm removing group, the blood stasis removing group and the phlegm-blood stasis co-treatment group. Alachloramine (3 mg/kg) was administered to the stomach by gavage in the alachloramine group. After 8 weeks, HE staining was used to observe the morphological changes of myocardial tissue in diabetic rats. Masson staining was used to observe the deposition of collagen fibers in the myocardial interstitium in rats. The expression of JNK1 protein was determined by immunohistochemistry. JNK1 mRNA, IRS1 mRNA and NLRP3 expression levels were detected by Real-time PCR. Western blot was used to detect the protein expressions of IRS-1, p-Akt and NLRP3.Results:The myocardial cells in the model group were disorganized, with hypertrophy, blurred texture, inflammatory infiltration of interstitium, increased collagen fibers, and focal necrosis. All treatment groups could improve fibrosis, inflammatory infiltration and reduce myocardial collagen deposition in different degrees. Compared with the model group, the mRNA and protein expressions of JNK1 and NLRP3 bodies decreased ( P<0.01), the IRS-1 mRNA and protein increased ( P<0.01), and p-Akt protein expression increased ( P<0.01). Conclusions:The phlegm and stasis co-treatment can effectively improve the cardiomyopathy of diabetes rats, and the effect is better than the phlegm-resolving method or the stasis resolving method alone. The mechanism may be related to the inhibition of JNK signaling pathway activation, reduce the expressions of JNK1 and NLRP3, and increase the IRS-1 and Akt.
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Objective:To evaluate the role of caveolin 3 (Cav-3) in diabetic cardiomyopathy and the relationship with endoplasmic reticulum stress in mice.Methods:This experiment was performed in two parts. Part Ⅰ in vivo experiment Sixteen clean-grade healthy adult male wild type mice weighing 18-20 g, were divided into 2 groups ( n=8 each) using a random number table method: control group(Control group) and diabetic cardiomyopathy group (DCM group). Another 8 Cav-3 KO mice were selected and served as Cav-3 KO + diabetic cardiomyopathy group (Cav-3 KO+ DCM group). Type 2 diabetic models were developed by high fat diet combined with intraperitoneal injection of streptozotocin (100 mg/kg). The left ventricular ejection fraction (EF), left ventricular short axis shortening rate (FS), left ventricular end-systolic diameter (LVESD) and left ventricular end-diastolic diameter (LVEDD) were measured by B ultrasound at 8 weeks. Then the mice were sacrificed, and the myocardial histomorphology was observed using HE staining. Part Ⅱ in vitro experiment HL-1 cardiomyocytes were divided into 3 groups ( n=6 each)using a random number table method: normal glucose group (NG group), high glucose group (HG group) and high glucose+ methyl-β-cyclodextrin group (HG+ β-CD group). The high glucose model was prepared by adding 50% glucose to a specialized culture medium until the final concentration reached 30 mmol/L, and HL-1 cardiomyocytes were continuously cultivated for 36 h. The cellular injury was assessed using LDH and CCK8 kits. The expression of endoplasmic reticulum stress-related proteins binding immunoglobulin protein (BiP), C/EBP-homologous protein (CHOP) and X-box binding protein 1 (XBP1-s) in myocardial tissues and HL-1 cells was detected by Western blot. Results:In vivo experiment Compared with Control group, the food intake, water intake, and heart mass/body mass were significantly increased, EF and FS were decreased, LVESD and LVEDD were increased, the expression of BiP, CHOP and XBP1-s was up-regulated, the expression of Cav-3 was down-regulated ( P<0.05), and the pathological damage was aggravated in DCM group and Cav-3 KO+ DCM group. Compared with DCM group, EF and FS were significantly decreased, LVESD and LVEDD were increased, the expression of BiP, CHOP and XBP1-s was up-regulated, the expression of Cav-3 was down-regulated ( P<0.05), and the pathological damage was aggravated in Cav-3 KO+ DCM group. In vitro experiment Compared with NG group, the cell viability was significantly decreased, LDH activity was increased, the expression of BiP, CHOP and XBP1-s was up-regulated, and the expression of Cav-3 was down-regulated in HG group and HG+ β-CD group ( P<0.05). Compared with HG group, the cell viability was significantly decreased, LDH was increased, the expression of BiP, CHOP and XBP1-s was up-regulated, and the expression of Cav-3 was down-regulated in HG+ β-CD group ( P<0.05). Conclusions:Down-regulation of Cav-3 expression aggravates myocardial injury in diabetes mellitus, and the mechanism is related to excessive activation of endoplasmic reticulum stress in mice.
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Objective:To evaluate the effect of resveratrol on ferropotosis in cardiomyocytes of mice with diabetic cardiomyopathy.Methods:Thirty healthy adult male C57BL/6 mice, aged 8 weeks, weighing 22-26 g, were divided into 3 groups ( n=10 each) using a random number table method: control group (group C), diabetic cardiomyopathy group (group DCM) and resveratrol group (group RSV). Freshly prepared streptozotocin (STZ) 40 mg·kg -1·d -1 was intraperitoneally injected for 5 consecutive days to develop the model of type 1 diabetes mellitus. After the model was successfully developed, resveratrol 25 mg·kg -1·d -1 was intragastrically given for 12 consecutive weeks in group RSV, while the equal volume of dimethyl sulfoxide was given instead in group C and group DCM. Echocardiography was performed to examine the cardiac structure and function at the end of the 12th week. Then mice were sacrificed, and myocardial tissue specimens were harvested for microscopic examination of the pathological changes of myocardial tissues (by Hematologist-Eosin staining) and mitochondrial morphology of myocardial cells (with a transmission electron microscope) and for determination of the contents of iron, malondialdehyde (MDA) and glutathione (GSH) (by colorimetry) and expression of glutathione peroxidase 4 (GPX4) (by Western blot). Results:Compared with group C, the left ventricular end-diastolic diameter and left ventricular end-systolic diameter were significantly increased, the left ventricular ejection fraction and left ventricular fractional shortening were decreased, the contents of iron and MDA were increased, the content of GSH was decreased, and the expression of GPX4 was down-regulated in group DCM ( P<0.05). Compared with group DCM, the left ventricular end-diastolic diameter and left ventricular end-systolic diameter were significantly decreased, the left ventricular fractional shortening and ejection fraction were increased, the contents of iron and MDA were decreased, the content of GSH was increased, the expression of GPX4 was up-regulated ( P<0.05), and the pathological changes of myocardial tissues and changes in mitochondrial morphology of myocardial cells were significantly attenuated in group RSV. Conclusions:The mechanism by which resveratrol attenuates myocardial injury and further improves cardiac dysfunction is related to inhibition of ferroptosis in cardiomyocytes of mice with diabetic cardiomyopathy.
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Objective To investigate the role and underlying mechanism of cathepsin B in myocar-dial injury in mice with diabetic cardiomyopathy(DCM).Methods Twenty 8-week-old male SPF C57BL/6 mice were randomly divided into wild-type(WT)group and WT DCM group,with 10 mice in each group.Another 20 8-week-old male SPF-grade mice with cathepsin B knockout(KO)were randomly and equally assigned to KO group and KO DCM group.HE staining was used to observe morphological changes,Prussian blue staining was employed to detect iron deposition,while immunohistochemical staining with 4-hydroxynonenal(4-HNE)was used to assess lipid peroxidation level in the myocardial tissues.Western blotting was performed to detect the expression of heme oxygenase-1(HO-1),superoxide dismutase 2(SOD2),and nuclear factor E2-related factor 2(Nrf2),while RT-PCR was applied to evaluate the expressions of Nrf-2,HO-1,and phospholipid hydroperoxide glutathione peroxidase 4(GPX4).Results Compared to the WT DCM group,the KO DCM group presented improved cell arrangement in cardiac tissues and sig-nificant reduction in inflammatory cell infiltration.Furthermore,the KO DCM group displayed a significant decrease in iron deposition compared to the WT DCM group.Additionally,the KO DCM group exhibited a significant reduction in 4-HNE expression compared to the WT DCM group.The protein levels of Nrf2,SOD2,and HO-1 were significant increased in the KO DCM group than the WT DCM group(0.68±0.21 vs 0.39±0.13,0.59±0.10 vs 0.28±0.09,1.03±0.10 vs 0.48±0.04,P＜0.05).Moreover,elevated mRNA levels of GPX4,Nrf2 and HO-1 were also observed in the KO DCM group than the WT DCM group(0.65±0.09 vs 0.40±0.10,0.61±0.11 vs 0.34±0.11,0.62±0.12 vs 0.39±0.09,P＜0.05).Conclusion Cathepsin B exacerbates myocardial injury in DCM mice through ferroptosis.
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OBJECTIVE: This study intended to explore the hypoglycemic and cardioprotective effects of 8-week aerobic interval training combined with liraglutide and elucidate the underlying mechanisms. METHOD: Male Wistar rats were randomly divided into 5 groups - normal control group (CON), diabetic cardiomyopathy group (DCM), high-dose liraglutide group (DH), low-dose liraglutide group (DL), and aerobic interval training combined with liraglutide group (DLE). High-fat diet and streptozotocin (STZ) were used to induce the DCM model, and both the liraglutide administration group and combination therapy group allocated to 8 weeks of either liraglutide or liraglutide and exercise intervention. Cardiac functions were analyzed by electrocardiography. Blood biochemical parameters were measured to judge glycemic control conditions. Hematoxylin and eosin (HE) staining and Sirus red staining was used to identify cardiac morphology and collagen accumulation, respectively. Advanced glycation end products (AGEs) were determined by enzymatic methods. The mRNA expression of myocardial remodeling genes (BNP, GSK3ß, α-MHC, ß-MHC and PPARα) and the protein expression of GLP-1, GLP-1R were analyzed. RESULTS: DCM rats developed hyperglycemia, impaired cardiac function with accumulation of AGEs and collagen (P < 0.05). The development of hyperglycemia and cardiac dysfunction was significantly attenuated with all interventions, as reduced cardiac fibrosis and improved cardiac function (P < 0.05). Cardiac remodeling genes were normalized after all interventions, these positive modifications were due to increased GLP-1 and GLP-1R expression in DCM heart (P < 0.05). Liraglutide combined with AIT significantly increased the diameters of cardiomyocytes, increased the α-MHC expressionx, reduced PPARαexpression and reduced the fluctuation of blood glucose level, which showed the safety and effective of medicine combined with exercise. CONCLUSION: Liraglutide combined with AIT intervention normalized blood glucose alleviates myocardial fibrosis and improves cardiac contractile function in DCM rats, supporting the efficacy and safety of the combination therapy.
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Cardiomiopatías Diabéticas , Hiperglucemia , Animales , Glucemia/metabolismo , Cardiomiopatías Diabéticas/tratamiento farmacológico , Cardiomiopatías Diabéticas/metabolismo , Eosina Amarillenta-(YS)/metabolismo , Eosina Amarillenta-(YS)/farmacología , Eosina Amarillenta-(YS)/uso terapéutico , Péptido 1 Similar al Glucagón/metabolismo , Productos Finales de Glicación Avanzada/metabolismo , Control Glucémico , Glucógeno Sintasa Quinasa 3 beta/metabolismo , Hematoxilina/metabolismo , Hematoxilina/farmacología , Hematoxilina/uso terapéutico , Hiperglucemia/tratamiento farmacológico , Hiperglucemia/terapia , Hipoglucemiantes/farmacología , Liraglutida/farmacología , Liraglutida/uso terapéutico , Masculino , Miocitos Cardíacos/metabolismo , PPAR alfa/metabolismo , ARN Mensajero/metabolismo , Ratas , Ratas Wistar , EstreptozocinaRESUMEN
AIMS: Diabetes mellitus (DM) often coexists in elderly hypertrophic cardiomyopathy (HCM) patients; however, its impact on clinical outcomes is unclear. METHODS: We compared clinical outcomes according to the presence of DM in a nationwide HCM cohort. RESULTS: In 9,883 HCM subjects (mean age 58.5 ± 13.1, men 71.7%), 1,327 (13.4%) had DM. During follow-up (mean 5.9 ± 2.5 years), end-stage renal disease (ESRD) progression, coronary events (myocardial infarction, coronary revascularization), heart failure (HF), cardiovascular mortality, and all-cause mortality occurred in 80 (0.8%), 365 (3.7%), 1,558 (15.8%), 354 (3.6%), and 877 (8.9%) subjects, respectively. DM HCM subjects had significantly higher risks of ESRD progression (HR 3.49, 95% CI 2.20-5.54) and HF (HR 1.15, 95% CI 1.01-1.32) compared to non-DM HCM subjects, independent of age, sex, ischemic heart disease, atrial fibrillation, and other comorbidities. There was a tendency for greater risk of ESRD progression, HF, and all-cause death in subjects with more advanced stage of DM (p-for-trend < 0.05 for all). Insulin-treated DM was associated with the highest risk. CONCLUSIONS: DM HCM subjects have higher risk of ESRD progression and HF. Considering the extended life expectancy of HCM and increasing number of elderly HCM subjects, active surveillance and management of DM-related outcomes should be highlighted.
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Fibrilación Atrial , Cardiomiopatía Hipertrófica , Diabetes Mellitus , Insuficiencia Cardíaca , Fallo Renal Crónico , Anciano , Fibrilación Atrial/complicaciones , Cardiomiopatía Hipertrófica/complicaciones , Cardiomiopatía Hipertrófica/epidemiología , Estudios de Cohortes , Diabetes Mellitus/epidemiología , Femenino , Insuficiencia Cardíaca/etiología , Humanos , Fallo Renal Crónico/complicaciones , Masculino , Persona de Mediana Edad , Factores de RiesgoRESUMEN
PURPOSE: Diabetic cardiomyopathy (DCM), a common complication of diabetes mellitus and is characterized by myocardial hypertrophy and myocardial fibrosis. Pyrroloquinoline quinone (PQQ), a natural nutrient, exerts strong protection against various myocardial diseases. Pyroptosis, a type of inflammation-related programmed cell death, is vital to the development of DCM. However, the protective effects of PQQ against DCM and the associated mechanisms are not clear. This study aimed to investigate whether PQQ protected against DCM and to determine the underlying molecular mechanism. METHODS: Diabetes was induced in mice by intraperitoneal injection of streptozotocin, after which the mice were administered PQQ orally (10, 20, or 40 mg/kg body weight/day) for 12 weeks. AC16 human myocardial cells were divided into the following groups and treated accordingly: control (5.5 mmol/L glucose), high glucose (35 mmol/L glucose), and HG + PQQ groups (1 and 10 nmol/L PQQ). Cells were treated for 24 h. RESULTS: PQQ reduced myocardial hypertrophy and the area of myocardial fibrosis, which was accompanied by an increase in antioxidant function and a decrease in inflammatory cytokine levels. Moreover, myocardial hypertrophy-(ANP and BNP), myocardial fibrosis-(collagen I and TGF-ß1), and pyroptosis-related protein levels decreased in the PQQ treatment groups. Furthermore, PQQ abolished mitochondrial dysfunction and the activation of NF-κB/IκB, and decreased NLRP3 inflammation-mediated pyroptosis in AC16 cells under high-glucose conditions. CONCLUSION: PQQ improved DCM in diabetic mice by inhibiting NF-κB/NLRP3 inflammasome-mediated cell pyroptosis. Long-term dietary supplementation with PQQ may be greatly beneficial for the treatment of DCM. Diagram of the underlying mechanism of the effects of PQQ on DCM. PQQ inhibits ROS generation and NF-κB activation, which stimulates activation of the NLRP3 inflammasome and regulates the expression of caspase-1, IL-1ß, and IL-18. The up-regulated inflammatory cytokines trigger myocardial hypertrophy and cardiac fibrosis and promote the pathological process of DCM.