Naringin protects cardiomyocytes against hyperglycemia-induced injuries in vitro and in vivo

Naringin: Cardioprotective properties and safety profile in diabetes treatment

Flavonoids derived from plants offer a broad spectrum of therapeutic potential for addressing metabolic syndrome, particularly diabetes mellitus (DM), a prevalent non-communicable disease. Hyperglycemia in DM is a known risk factor for cardiovascular diseases (CVDs), which substantially impact global mortality rates. This review examines the potential effects of naringin, a citrus flavonoid, on both DM and its associated cardiovascular complications, including conditions like diabetic cardiomyopathy. The safety profile of naringin is summarized based on various pre-clinical studies. The data for this review was gathered from diverse electronic databases, including Medline, PubMed, ScienceDirect, SpringerLink, Google Scholar, and Emerald Insight. Multiple pre-clinical studies have demonstrated that naringin exerts hypoglycemic and cardioprotective effects by targeting various vascular mechanisms. Specifically, research indicates that naringin down-regulates the renin-angiotensin and oxidative stress systems while concurrently upregulating β-cell and immune system functions. Clinical trial outcomes also support the therapeutic potential of naringin in managing hyperglycemic states and associated cardiovascular issues. Moreover, toxicity studies have confirmed the safety of naringin in animal models, suggesting its potential for safe administration in humans. In conclusion, naringin emerges as a promising natural candidate for both antidiabetic and cardioprotective purposes, offering potential improvements in health outcomes. While naringin presents a new avenue for therapies targeting DM and CVDs, additional controlled and long-term clinical trials are necessary to validate its efficacy and safety for human use.

Natural products as pharmacological modulators of mitochondrial dysfunctions for the treatment of diabetes and its complications: An update since 2010

Diabetes, characterized as a well-known chronic metabolic syndrome, with its associated complications pose a substantial and escalating health and healthcare challenge on a global scale. Current strategies addressing diabetes are mainly symptomatic and there are fewer available curative pharmaceuticals for diabetic complications. Thus, there is an urgent need to identify novel pharmacological targets and agents. The impaired mitochondria have been associated with the etiology of diabetes and its complications, and the intervention of mitochondrial dysfunction represents an attractive breakthrough point for the treatments of diabetes and its complications. Natural products (NPs), with multicenter characteristics, multi-pharmacological activities and lower toxicity, have been caught attentions as the modulators of mitochondrial functions in the therapeutical filed of diabetes and its complications. This review mainly summarizes the recent progresses on the potential of 39 NPs and 2 plant-extracted mixtures to improve mitochondrial dysfunction against diabetes and its complications. It is expected that this work may be useful to accelerate the development of innovative drugs originated from NPs and improve upcoming therapeutics in diabetes and its complications.

Naringin exerts antiarrhythmic effects by inhibiting channel currents in mouse cardiomyocytes

INTRODUCTION

Naringin, a flavonoid extracted from citrus plants, has a variety of biological effects. Studies have shown that increasing the consumption of flavonoid-rich foods can reduce the incidence of cardiac arrhythmia. Naringin has been reported to have beneficial cardiovascular effects and thus can be used to prevent cardiovascular diseases, but the electrophysiological mechanism through which it prevents arrhythmias has not been elucidated. This study was conducted to investigate the effect of naringin on the transmembrane ion channel currents in mouse ventricular myocytes and the antiarrhythmic effect of this compound on Langendorff-perfused mouse hearts.

METHODS

Action potentials (APs) and ionic currents were recorded in isolated ventricular myocytes using the whole-cell patch-clamp technique. Anemone toxin II (ATX II) and CaCl2 were used to induce early afterdepolarizations (EADs) and delayed afterdepolarizations (DADs), respectively. Electrocardiogram (ECG) recordings were conducted in Langendorff-perfused mouse hearts with a BL-420F biological signal acquisition and analysis system.

RESULTS

At the cellular level, naringin shortened the action potential duration (APD) of ventricular myocytes and decreased the maximum depolarization velocity (Vmax) of APs.Naringin inhibited the L-type calcium current (ICa.L) and ATX II enhanced the late sodium current (INa.L) in a concentration-dependent manner with IC50 values of 508.5 μmol/L (n = 9) and 311.6 μmol/L (n = 10), respectively. In addition, naringin also inhibited the peak sodium current (INa·P) and delayed the rectifier potassium current (IK) and the transient outward potassium current (Ito). Moreover, naringin reduced ATX II-induced APD prolongation and EADs and had a significant inhibitory effect on CaCl2-induced DADs as well. At the organ level, naringin reduced the incidence of ventricular tachycardia (VT) and ventricular fibrillation (VF) induced by ATX II and shortened the duration of both in isolated hearts.

CONCLUSION

Naringin can inhibit the occurrence of EADs and DADs at the cellular level; furthermore, it can inhibit INa.L, ICa.L, INa·P, IK, and Ito in ventricular myocytes. Naringin also inhibits arrhythmias induced by ATX II in hearts. By investigating naringin with this electrophysiological method for the first time, we determined that this flavonoid may be a multichannel blocker with antiarrhythmic effects.

Targeting oxidative stress as a preventive and therapeutic approach for cardiovascular disease

Cardiovascular diseases (CVDs) continue to exert a significant impact on global mortality rates, encompassing conditions like pulmonary arterial hypertension (PAH), atherosclerosis (AS), and myocardial infarction (MI). Oxidative stress (OS) plays a crucial role in the pathogenesis and advancement of CVDs, highlighting its significance as a contributing factor. Maintaining an equilibrium between reactive oxygen species (ROS) and antioxidant systems not only aids in mitigating oxidative stress but also confers protective benefits on cardiac health. Herbal monomers can inhibit OS in CVDs by activating multiple signaling pathways, such as increasing the activity of endogenous antioxidant systems and decreasing the level of ROS expression. Given the actions of herbal monomers to significantly protect the normal function of the heart and reduce the damage caused by OS to the organism. Hence, it is imperative to recognize the significance of herbal monomers as prospective therapeutic interventions for mitigating oxidative damage in CVDs. This paper aims to comprehensively review the origins and mechanisms underlying OS, elucidate the intricate association between CVDs and OS, and explore the therapeutic potential of antioxidant treatment utilizing herbal monomers. Furthermore, particular emphasis will be placed on examining the cardioprotective effects of herbal monomers by evaluating their impact on cardiac signaling pathways subsequent to treatment.

Nox4 as a novel therapeutic target for diabetic vascular complications

Diabetic vascular complications can affect both microvascular and macrovascular. Diabetic microvascular complications, such as diabetic nephropathy, diabetic retinopathy, diabetic neuropathy, and diabetic cardiomyopathy, are believed to be caused by oxidative stress. The Nox family of NADPH oxidases is a significant source of reactive oxygen species and plays a crucial role in regulating redox signaling, particularly in response to high glucose and diabetes mellitus. This review aims to provide an overview of the current knowledge about the role of Nox4 and its regulatory mechanisms in diabetic microangiopathies. Especially, the latest novel advances in the upregulation of Nox4 that aggravate various cell types within diabetic kidney disease will be highlighted. Interestingly, this review also presents the mechanisms by which Nox4 regulates diabetic microangiopathy from novel perspectives such as epigenetics. Besides, we emphasize Nox4 as a therapeutic target for treating microvascular complications of diabetes and summarize drugs, inhibitors, and dietary components targeting Nox4 as important therapeutic measures in preventing and treating diabetic microangiopathy. Additionally, this review also sums up the evidence related to Nox4 and diabetic macroangiopathy.

Naringenin and apigenin ameliorates corticosterone-induced depressive behaviors

Background

Depression is a common kind of mental illness, and it becomes the main health burden in the world.

Purpose

The aim of this study was to investigate the antidepressant effects of naringin and apigenin isolated from Chrysanthemum morifolium Ramatis.

Methods

Firstly, 20 mg/kg corticosterone (CORT) was injected into mice to establish an in vivo model of depression. After treated with different dosages of naringenin and apigenin for 3 weeks, the mice underwent a series of behavioral experiments. Following this, all mice were sacrificed and biochemical analyses were performed. Subsequently, CORT (500 μM) induced PC12 cells was used as an in vitro model of depression, and lipopolysaccharide (LPS) (1 μg ml^-1) induced N9 microglia cells was used as an in vitro model of neuroinflammation in N9 microglia cells, to investigate the neuroprotective mechanisms of naringenin and apigenin.

Results

Results showed that the naringenin and apigenin treatment ameliorated CORT-induced sucrose preference decrease and immobility time increase, elevated the 5-hydroxytryptamine(5-HT), dopamine (DA) and norepinephrine (NE) levels, and enhanced the cAMP-response element binding protein (CREB) and brain derived neurotrophic factor (BDNF) protein expressions in the hippocampus. The results showed that the naringenin and apigenin treatment improved the PC-12 cell viability through reducing apoptosis rate induced by CORT. Furthermore, naringenin and apigenin were able to inhibit the activation of N9 cells after LPS induction, and shift microglia from proinflammatory M1 microglia toward anti-inflammatory M2 microglia, as evidenced by the decreased ratio of M1 type microglia marker CD86 and M2 type microglia marker CD86.

Conclusion

These results suggested that naringenin and apigenin may improve depressive behaviors through promoting BDNF and inhibiting neuroinflammation and neuronal apoptosis.

Investigation of the efficacy of diosmin against organ damage caused by bendiocarb in male Wistar albino rats

Bendiocarb is a carbamate insecticide, which is used more in indoor areas, especially against scorpions, spiders, flies, mosquitoes and cockroaches. Diosmin is an antioxidant flavonoid found mostly in citrus fruits. In this study, the efficacy of diosmin against the adverse effects of bendiocarb was investigated in rats. For this purpose, 60, 2-3 month-old male Wistar albino rats, weighing 150-200 g, were used. The animals were assigned to six groups, one of which was maintained for control purposes and five of which were trial groups. The control rats received only corn oil, which was used as a vehicle for diosmin administration in the trial groups. Groups 2, 3, 4, 5 and 6 were administered with 10 mg/kg.bw bendiocarb, 10 mg/kg.bw diosmin, 20 mg/kg.bw diosmin, 2 mg/kg.bw bendiocarb plus 10 mg/kg.bw diosmin, and 2 mg/kg.bw bendiocarb plus 20 mg/kg.bw diosmin, respectively, using an oral catheter, for 28 days. At the end of the study period, blood and organ (liver, kidneys, brain, testes, heart and lungs) samples were collected. Body weight and organ weights were determined. Compared to the control group, in the group given bendiocarb alone, firstly, body weight and liver, lung and testicular weights decreased. Secondly, tissue/plasma malondialdehyde (MDA) and nitric oxide (NO) levels increased, and glutathione (GSH) levels and superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) (except for lung tissue), glutathione reductase (GR), and glucose-6-phosphate dehydrogenase (G6PD) activities decreased in all tissues and erythrocytes. Thirdly, catalase (CAT) activity decreased in erythrocytes and the kidney, brain, heart and lung tissues and increased in the liver and testes. Fourthly, while GST activity decreased in the kidneys, testes, lung and erythrocytes, an increase was observed in the liver and heart tissues. Fifthly, while serum triglyceride levels and lactate dehydrogenase (LDH), alkaline phosphatase (ALP) and pseudo-cholinesterase (PchE) activities decreased, aspartate aminotransferase (AST) and alanine aminotransferase (ALT) activities and blood urea nitrogen (BUN), creatinine and uric acid levels increased. Lastly, liver caspase 3, caspase 9 and p53 expression levels significantly increased. When compared to the control group, the groups treated with diosmin alone showed no significant difference for the parameters investigated. On the other hand, it was observed that the values of the groups treated with a combination of bendiocarb and diosmin were closer to the values of the control group. In conclusion, while exposure to bendiocarb at a dose of 2 mg/kg.bw for 28 days caused oxidative stress/organ damage, diosmin administration at doses of 10 and 20 mg/kg.bw reduced this damage. This demonstrated that diosmin has pharmaceutical benefits, when used for supportive treatment as well as radical treatment, against the potential adverse effects of bendiocarb.

Targeting epigenetics in diabetic cardiomyopathy: Therapeutic potential of flavonoids

The pathophysiological mechanisms of diabetic cardiomyopathy have been extensively studied, but there is still a lack of effective prevention and treatment methods. The ability of flavonoids to protect the heart from diabetic cardiomyopathy has been extensively described. In recent years, epigenetics has received increasing attention from scholars in exploring the etiology and treatment of diabetes and its complications. DNA methylation, histone modifications and non-coding RNAs play key functions in the development, maintenance and progression of diabetic cardiomyopathy. Hence, prevention or reversal of the epigenetic alterations that have occurred during the development of diabetic cardiomyopathy may alleviate the personal and social burden of the disease. Flavonoids can be used as natural epigenetic modulators in alternative therapies for diabetic cardiomyopathy. In this review, we discuss the epigenetic effects of different flavonoid subtypes in diabetic cardiomyopathy and summarize the evidence from preclinical and clinical studies that already exist. However, limited research is available on the potential beneficial effects of flavonoids on the epigenetics of diabetic cardiomyopathy. In the future, clinical trials in which different flavonoids exert their antidiabetic and cardioprotective effects through various epigenetic mechanisms should be further explored.

Cardioprotective Effects of Grapefruit IntegroPectin Extracted via Hydrodynamic Cavitation from By-Products of Citrus Fruits Industry: Role of Mitochondrial Potassium Channels

Citrus flavonoids are well-known for their beneficial effects at the cardiovascular and cardio-metabolic level, but often the encouraging in vitro results are not confirmed by in vivo approaches; in addition, the clinical trials are also inconsistent. Their limited bioavailability can be, at least in part, the reason for these discrepancies. Therefore, many efforts have been made towards the improvement of their bioavailability. Hydrodynamic cavitation methods were successfully applied to the extraction of byproducts of the Citrus fruits industry, showing high process yields and affording stable phytocomplexes, known as IntegroPectin, endowed with great amounts of bioactive compounds and high water solubility. The cardioprotective effects of grapefruit IntegroPectin were evaluated by an ex vivo ischemia/reperfusion protocol. Further pharmacological characterization was carried out to assess the involvement of mitochondrial potassium channels. Grapefruit IntegroPectin, where naringin represented 98% of the flavonoids, showed anti-ischemic cardioprotective activity, which was better than pure naringenin (the bioactive aglycone of naringin). On cardiac-isolated mitochondria, this extract confirmed that naringenin/naringin were involved in the activation of mitochondrial potassium channels. The hydrodynamic cavitation-based extraction confirmed a valuable opportunity for the exploitation of Citrus fruits waste, with the end product presenting high levels of Citrus flavonoids and improved bioaccessibility that enhances its nutraceutical and economic value.

Integrating pharmacological evaluation and computational identification for deciphering the action mechanism of Yunpi-Huoxue-Sanjie formula alleviates diabetic cardiomyopathy

Background: Yunpi-Huoxue-Sanjie (YP-SJ) formula is a Chinese herbal formula with unique advantages for the treatment of diabetic cardiovascular complications, such as Diabetic cardiomyopathy (DCM). However, potential targets and molecular mechanisms remain unclear. Therefore, our research was designed to evaluate rat myocardial morphology, fat metabolism and oxidative stress to verify myocardial protective effect of YP-SJ formula in vivo. And then to explore and validate its probable mechanism through network pharmacology and experiments in vitro and in vivo.

Methods: In this study, DCM rats were randomly divided into five groups: control group, model group, and three YP-SJ formula groups (low-dose, middle-dose, and high-dose groups). Experimental rats were treated with 6 g/kg/d, 12 g/kg/d and 24 g/kg/d YP-SJ formula by gavage for 10 weeks, respectively. Cardiac function of rats was measured by high-resolution small-animal imaging system. The cells were divided into control group, high glucose group, high glucose + control serum group, high glucose + dosed serum group, high glucose + NC-siRNA group, high glucose + siRNA-FoxO1 group. The extent of autophagy was measured by flow cytometry, immunofluorescence, and western blotting.

Results: It was found that YP-SJ formula could effectively improve cardiac systolic function in DCM rats. We identified 46 major candidate YP-SJ formula targets that are closely related to the progression of DCM. Enrichment analysis revealed key targets of YP-SJ formula related to environmental information processing, organic systems, and the metabolic occurrence of reactive oxygen species. Meanwhile, we verified that YP-SJ formula can increase the expression of forkhead box protein O1 (FoxO1), autophagy-related protein 7 (Atg7), Beclin 1, and light chain 3 (LC3), and decrease the expression of phosphorylated FoxO1 in vitro and in vivo. The results showed that YP-SJ formula could activate the FoxO1 signaling pathway associated with DCM rats. Further experiments showed that YP-SJ formula could improve cardiac function by regulating autophagy.

Conclusion: YP-SJ formula treats DCM by modulating targets that play a key role in autophagy, improving myocardial function through a multi-component, multi-level, multi-target, multi-pathway, and multi-mechanism approach.

KDM3A Inhibition Ameliorates Hyperglycemia-Mediated Myocardial Injury by Epigenetic Modulation of Nuclear Factor Kappa-B/P65

Objectives

Even after the glucose level returns to normal, hyperglycemia-induced cardiac dysfunction as well as reactive oxygen species (ROS) generation, inflammatory responses, and apoptosis continued deterioration, showing a long-lasting adverse effect on cardiac function and structure. We aimed to unveil the molecular and cellular mechanisms underlying hyperglycemia-induced persistent myocardial injury and cardiac dysfunction.

Methods and Results

Recently, the accumulated evidence indicated epigenetic regulation act as a determining factor in hyperglycemia-induced continuous cardiovascular dysfunction. As an important histone demethylase, the expression of lysine-specific demethylase 3A (KDM3A) was continually increased, accompanied by a sustained decline of H3K9me2 levels in diabetic myocardium even if received hypoglycemic therapy. Besides, by utilizing gain- and loss-of-functional approaches, we identified KDM3A as a novel regulator that accelerates hyperglycemia-mediated myocardial injury by promoting ROS generation, aggregating inflammatory reaction, and facilitating cell apoptosis in vitro and in vivo. The KDM3A inhibition could significantly ameliorate the adverse effect of hyperglycemia in both diabetes model and diabetic intensive glycemic control model. Mechanically, our data uncovered that KDM3A could promote the expression and transcriptional activity of nuclear factor kappa-B (NF-κB/P65), and the succedent rescue experiments further verified that KDM3A regulates hyperglycemia-induced myocardial injury in an NF-κB/P65 dependent manner.

Conclusion

This study revealed histone-modifying enzymes KDM3A drives persistent oxidative stress, inflammation, apoptosis, and subsequent myocardial injury in the diabetic heart by regulating the transcription of NF-κB/P65.

Receptor Interacting Protein Kinases 1/3: The Potential Therapeutic Target for Cardiovascular Inflammatory Diseases

The receptor interacting protein kinases 1/3 (RIPK1/3) have emerged as the key mediators in cell death pathways and inflammatory signaling, whose ubiquitination, phosphorylation, and inhibition could regulate the necroptosis and apoptosis effectually. Recently, more and more studies show great interest in the mechanisms and the regulator of RIPK1/3-mediated inflammatory response and in the physiopathogenesis of cardiovascular diseases. The crosstalk of autophagy and necroptosis in cardiomyocyte death is a nonnegligible conversation of cell death. We elaborated on RIPK1/3-mediated necroptosis, pathways involved, the latest regulatory molecules and therapeutic targets in terms of ischemia reperfusion, myocardial remodeling, myocarditis, atherosclerosis, abdominal aortic aneurysm, and cardiovascular transplantation, etc.

Eugenosedin-A improves obesity-related hyperglycemia by regulating ATP-sensitive K+ channels and insulin secretion in pancreatic β cells

Eugenosedin-A (Eu-A) has been shown to protect against hyperglycemia- and hyperlipidemia-induced metabolic syndrome. We investigated the relationship of K_ATP channel activities and insulin secretion by Eu-A in vitro in pancreatic β-cells, and examined the effect of Eu-A on streptozotocin (STZ)/nicotinamide (NA)-induced type 2 diabetes mellitus (T2DM) in vivo. We isolated pancreatic islets from adult male Wistar rats (250-350 g) and identified pancreatic β-cells by the cell size, capacitance and membrane potential. Perforated patch-clamp and inside-out recordings were used to monitor the membrane potential (current-clamp mode) and channel activity (voltage-clamp mode) of β-cells. The membrane potential of β-cells was raised by Eu-A and reversed by the K_ATP channel activator diazoxide. Eu-A inhibited the K_ATP channel activity measured at - 60 mV and increased the intracellular calcium concentration ([Ca²⁺]_i), resulting in enhanced insulin secretion. Eu-A also reduced Kir6.2 protein on the cell membrane and scattered in the cytosol under normal glucose conditions (5.6 mM). In our animal study, rats were divided into normal and STZ/NA-induced T2DM groups. Normal rats fed with regular chow were divided into control and control+Eu-A (5 mg/kg/day, i.p.) groups. The STZ/NA-induced diabetic rats fed with a high-fat diet (HFD) were divided into three groups: T2DM, T2DM+Eu-A (5 mg/kg/day, i.p.), and T2DM+glibenclamide (0.5 mg/kg/day, i.p.; a K_ATP channel inhibitor). Both Eu-A and glibenclamide decreased the rats' blood glucose, prevented weight gain, and enhanced insulin secretion. We found that Eu-A blocked pancreatic β-cell K_ATP channels, caused membrane potential depolarization, and stimulated Ca²⁺ influx, thus increasing insulin secretion. Furthermore, Eu-A decreased blood glucose and increased insulin levels in T2DM rats. These results suggested that Eu-A might have clinical benefits for the control of T2DM and its complications.

Omnifarious fruit polyphenols: an omnipotent strategy to prevent and intervene diabetes and related complication?

Diabetes mellitus is a metabolic syndrome which cannot be cured. Recently, considerable interest has been focused on food ingredients to prevent and intervene in complications of diabetes. Polyphenolic compounds are one of the bioactive phytochemical constituents with various biological activities, which have drawn increasing interest in human health. Fruits are part of the polyphenol sources in daily food consumption. Fruit-derived polyphenols possess the anti-diabetic activity that has already been proved either from in vitro studies or in vivo studies. The mechanisms of fruit polyphenols in treating diabetes and related complications are under discussion. This is a comprehensive review on polyphenols from the edible parts of fruits, including those from citrus, berries, apples, cherries, mangoes, mangosteens, pomegranates, and other fruits regarding their potential benefits in preventing and treating diabetes mellitus. The signal pathways of characteristic polyphenols derived from fruits in reducing high blood glucose and intervening hyperglycemia-induced diabetic complications were summarized.

Therapeutic Approach of Flavonoid in Ameliorating Diabetic Cardiomyopathy by Targeting Mitochondrial-Induced Oxidative Stress

Diabetes cardiomyopathy is one of the key factors of mortality among diabetic patients around the globe. One of the prior contributors to the progression of diabetic cardiomyopathy is cardiac mitochondrial dysfunction. The cardiac mitochondrial dysfunction can induce oxidative stress in cardiomyocytes and was found to be the cause of majority of the heart morphological and dynamical changes in diabetic cardiomyopathy. To slow down the occurrence of diabetic cardiomyopathy, it is crucial to discover therapeutic agents that target mitochondrial-induced oxidative stress. Flavonoid is a plentiful phytochemical in plants that shows a wide range of biological actions against human diseases. Flavonoids have been extensively documented for their ability to protect the heart from diabetic cardiomyopathy. Flavonoids' ability to alleviate diabetic cardiomyopathy is primarily attributed to their antioxidant properties. In this review, we present the mechanisms involved in flavonoid therapies in ameliorating mitochondrial-induced oxidative stress in diabetic cardiomyopathy.

Effects of Naringin on Cardiomyocytes From a Rodent Model of Type 2 Diabetes

Diabetic cardiomyopathy (DCM) is a primary disease in diabetic patients characterized by diastolic dysfunction leading to heart failure and death. Unfortunately, even tight glycemic control has not been effective in its prevention. We have found aberrant diastolic Ca2+ concentrations ([Ca2+]d), decreased glucose transport, elevated production of reactive oxygen species (ROS), and increased calpain activity in cardiomyocytes from a murine model (db/db) of type 2 diabetes (T2D). Cardiomyocytes from these mice demonstrate significant cell injury, increased levels of tumor necrosis factor-alpha and interleukin-6 and expression of the transcription nuclear factor-κB (NF-κB). Furthermore, decreased cell viability, and reduced expression of Kir6.2, SUR1, and SUR2 subunits of the ATP-sensitive potassium (KATP) channels. Treatment of T2D mice with the citrus fruit flavonoid naringin for 4 weeks protected cardiomyocytes by reducing diastolic Ca2+ overload, improving glucose transport, lowering reactive oxygen species production, and suppressed myocardial inflammation. In addition, naringin reduced calpain activity, decreased cardiac injury, increased cell viability, and restored the protein expression of Kir6.2, SUR1, and SUR2 subunits of the KATP channels. Administration of the KATP channel inhibitor glibenclamide caused a further increase in [Ca2+]d in T2D cardiomyocytes and abolished the naringin effect on [Ca2+]d. Nicorandil, a KATP channel opener, and nitric oxide donor drug mimic the naringin effect on [Ca2+]d in T2D cardiomyocyte; however, it aggravated the hyperglycemia in T2D mice. These data add new insights into the mechanisms underlying the beneficial effects of naringin in T2D cardiomyopathy, thus suggesting a novel approach to treating this cardiovascular complication.

Network Pharmacological Study and Molecular Docking Analysis of Qiweitangping in Treating Diabetic Coronary Heart Disease

Background

Coronary heart disease (CHD) is one of the most important complications of diabetes mellitus, having a high disability fatality rate. Qiweitangping is a Chinese medicine to control diabetes (type 1 and type 2 diabetes) and complications, having been used in clinic for more than 20 years, with the expected therapeutic effect. In a previous clinical study, the total effective rate of the drug for the treatment of type 2 diabetes reached 92.7%. However, the mechanism of the treatment process is unclear. Therefore, this research was conducted to explore the mechanism of treating diabetic coronary heart disease with the assistance of bioinformatics methods.

Methods

The TCMSP database was used to collect the effective chemical constituents of Qiweitangping and the target genes of the chemical constituents, and the related genes of diabetic CHD were obtained from the GeneCard database. Furthermore, the intersection was found between the target gene of the drug and the related gene of the disease to obtain the candidate genes; the STRING database and DAVID database were used to perform protein interaction analysis and KEGG enrichment analysis on the candidate genes. Also, molecular docking was used for auxiliary verification. Finally, a “drug component-gene target-pathway” network was constructed by using Cytoscape software.

Results

Sixty-two effective chemical components including naringin, diosgenin, formogenin, isorolin, and isocryptanshinone, fifty-nine candidate target genes (such as AKT1, CASP3, and VEGF-A), and thirty-nine related pathways in Qiweitangping were obtained. In addition, two pairs (CASP-naringenin and STAT3-cryptotanshinone) of molecular docking results showed good affinity (<−5.00 kcal/mol).

Conclusion

The results of the study indicate that Qiweitangping treats diabetic CHD with multiple chemical components. Its mechanism of action may be related to the HIF-1 signaling pathway, PI3K-Akt signaling pathway, and ErbB signaling pathway. STAT3 and CASP genes have been verified by molecular docking to have a relatively good combination with Qiweitangping. This study is the theoretical basis for further experimental study on the treatment mechanism of diabetic CHD with Qiweitangping.

Effects of Bergamot Polyphenols on Mitochondrial Dysfunction and Sarcoplasmic Reticulum Stress in Diabetic Cardiomyopathy

Cardiovascular disease is the leading cause of death and disability in the Western world. In order to safeguard the structure and the functionality of the myocardium, it is extremely important to adequately support the cardiomyocytes. Two cellular organelles of cardiomyocytes are essential for cell survival and to ensure proper functioning of the myocardium: mitochondria and the sarcoplasmic reticulum. Mitochondria are responsible for the energy metabolism of the myocardium, and regulate the processes that can lead to cell death. The sarcoplasmic reticulum preserves the physiological concentration of the calcium ion, and triggers processes to protect the structural and functional integrity of the proteins. The alterations of these organelles can damage myocardial functioning. A proper nutritional balance regarding the intake of macronutrients and micronutrients leads to a significant improvement in the symptoms and consequences of heart disease. In particular, the Mediterranean diet, characterized by a high consumption of plant-based foods, small quantities of red meat, and high quantities of olive oil, reduces and improves the pathological condition of patients with heart failure. In addition, nutritional support and nutraceutical supplementation in patients who develop heart failure can contribute to the protection of the failing myocardium. Since polyphenols have numerous beneficial properties, including anti-inflammatory and antioxidant properties, this review gathers what is known about the beneficial effects of polyphenol-rich bergamot fruit on the cardiovascular system. In particular, the role of bergamot polyphenols in mitochondrial and sarcoplasmic dysfunctions in diabetic cardiomyopathy is reported.

Natural and synthetic antioxidants targeting cardiac oxidative stress and redox signaling in cardiometabolic diseases

Cardiometabolic diseases (CMDs) are metabolic diseases (e.g., obesity, diabetes, atherosclerosis, rare genetic metabolic diseases, etc.) associated with cardiac pathologies. Pathophysiology of most CMDs involves increased production of reactive oxygen species and impaired antioxidant defense systems, resulting in cardiac oxidative stress (OxS). To alleviate OxS, various antioxidants have been investigated in several diseases with conflicting results. Here we review the effect of CMDs on cardiac redox homeostasis, the role of OxS in cardiac pathologies, as well as experimental and clinical data on the therapeutic potential of natural antioxidants (including resveratrol, quercetin, curcumin, vitamins A, C, and E, coenzyme Q10, etc.), synthetic antioxidants (including N-acetylcysteine, SOD mimetics, mitoTEMPO, SkQ1, etc.), and promoters of antioxidant enzymes in CMDs. As no antioxidant indicated for the prevention and/or treatment of CMDs has reached the market despite the large number of preclinical and clinical studies, a sizeable translational gap is evident in this field. Thus, we also highlight potential underlying factors that may contribute to the failure of translation of antioxidant therapies in CMDs.

Naringenin alleviates myocardial ischemia reperfusion injury by enhancing the myocardial miR-126-PI3K/AKT axis in streptozotocin-induced diabetic rats

Ischemic heart disease (IHD) is a leading cause of death in patients with type 1 diabetes. The key to treating IHD is to restore blood supply to the ischemic myocardium, which inevitably causes myocardial ischemia reperfusion (MI/R) injury. Although naringenin (Nar) prevents MI/R injury, the role of Nar in diabetic MI/R (D-MI/R) injury remains to be elucidated. The PI3K/AKT signaling pathway and microRNA (miR)-126 have previously been shown to serve anti-MI/R injury roles. The present study aimed to investigate the protection of Nar against D-MI/R injury and the role of the miR-126-PI3K/AKT axis. Diabetic rats were treated distilled water or Nar (25 or 50 mg/kg, orally) for 30 days and then exposed to MI/R. The present results revealed that Nar alleviated MI/R injury in streptozotocin (STZ)-induced diabetic rats, as shown below: the reduction myocardial enzymes levels was measured using spectrophotometry, the increase of cardiac viability was detected by MTT assay, the inhibition of myocardial oxidative stress was measured using spectrophotometry and the enhancement of cardiac function were recorded using a hemodynamic monitoring system. Furthermore, Nar upregulated the myocardial miR-126-PI3K/AKT axis in D-MI/R rats. These results indicated that Nar alleviated MI/R injury through upregulating the myocardial miR-126-PI3K/AKT axis in STZ-induced diabetic rats. The current findings revealed that Nar, as an effective agent against D-MI/R injury, may provide an effective approach in the management of diabetic IHD.

Modulations of Cardiac Functions and Pathogenesis by Reactive Oxygen Species and Natural Antioxidants

Homeostasis in the level of reactive oxygen species (ROS) in cardiac myocytes plays a critical role in regulating their physiological functions. Disturbance of balance between generation and removal of ROS is a major cause of cardiac myocyte remodeling, dysfunction, and failure. Cardiac myocytes possess several ROS-producing pathways, such as mitochondrial electron transport chain, NADPH oxidases, and nitric oxide synthases, and have endogenous antioxidation mechanisms. Cardiac Ca²⁺-signaling toolkit proteins, as well as mitochondrial functions, are largely modulated by ROS under physiological and pathological conditions, thereby producing alterations in contraction, membrane conductivity, cell metabolism and cell growth and death. Mechanical stresses under hypertension, post-myocardial infarction, heart failure, and valve diseases are the main causes for stress-induced cardiac remodeling and functional failure, which are associated with ROS-induced pathogenesis. Experimental evidence demonstrates that many cardioprotective natural antioxidants, enriched in foods or herbs, exert beneficial effects on cardiac functions (Ca²⁺ signal, contractility and rhythm), myocytes remodeling, inflammation and death in pathological hearts. The review may provide knowledge and insight into the modulation of cardiac pathogenesis by ROS and natural antioxidants.

Anti-Inflammatory Effects of Quercetin on High-Glucose and Pro-Inflammatory Cytokine Challenged Vascular Endothelial Cell Metabolism

SCOPE

Pro-inflammatory stimuli such as hyperglycemia and cytokines have been shown to negatively affect endothelial cell functions. The aim of this study is to assess the potential of quercetin and its human metabolites to overcome the deleterious effects of hyperglycemic or inflammatory conditions on the vascular endothelium by modulating endothelial cell metabolism.

METHODS AND RESULTS

A metabolomics approach enabled identification and quantification of 27 human umbilical vein endothelial cell (HUVEC) metabolites. Treatment of HUVECs with high-glucose concentrations causes significant increases in lactate and glutamate concentrations. Quercetin inhibits glucose-induced increases in lactate and adenosine 5'-triphosphate (ATP) and also increased inosine concentrations. Tumor necrosis factor α-treatment (TNFα) of HUVECs causes increases in asparagine and decreases in aspartate concentrations. Co-treatment with quercetin reduces pyruvate concentrations compared to TNFα-only treated controls. Subsequently, it was shown that quercetin and its HUVEC phase-2 conjugates inhibit adenosine deaminase, xanthine oxidase and 5'nucleotidase (CD73) but not ectonucleoside triphosphate diphosphohydrolase-1 (CD39) or purine nucleoside phosphorylase activities.

CONCLUSION

Quercetin was shown to alter the balance of HUVEC metabolites towards a less inflamed phenotype, both alone and in the presence of pro-inflammatory stimuli. These changes are consistent with the inhibition of particular enzymes involved in purine metabolism by quercetin and its HUVEC metabolites.

A Novel Drug Delivery System: the Encapsulation of Naringenin in Metal-Organic Frameworks into Liposomes

Poorly water-soluble naringenin (NAR) was selected as a model drug and loaded into the porous MOFs for the construction of NAR@ZIF-8 inclusion complex. By film dispersion method, NAR@ZIF-8 was further encapsulated into liposomes to fabricate a novel drug delivery system. Liposomes and a novel drug delivery system were established. Subsequently, the lipid-drug ratio, phospholipid-cholesterol ratio, and hydration temperature were investigated using the Box-Behnken design based the single factor experiment. The prepared liposomes system showed spherical or quasi-spherical shape, uniform particle size distribution, and complete structure. More specifically, the average particle size was 113.2 ± 1.4 nm, and zeta potential was - 7.536 ± 0.264 mV. Moreover, the drug release behaviors of NAR, NAR@ZIF-8, and NAR@ZIF-8 liposomes were explored in vitro. Compared with free NAR and NAR@ZIF-8 which exhibited a burst drug release, NAR@ZIF-8 liposomes showed a more sustained release behavior with 79.86% drug release in 72 h. In vitro cytotoxicity experiments showed that, compared with free NAR and NAR@ZIF-8, NAR@ZIF-8 liposomes exhibited higher inhibition efficiency on lung adenocarcinoma A549 cells and gastric cancer SGC-7901 cells in a concentration-dependent manner.

Naringin attenuates high glucose-induced injuries and inflammation by modulating the leptin-JAK2/STAT3 pathway in H9c2 cardiac cells

INTRODUCTION

Our previous study showed that naringin (NRG) protects cardiomyocytes against high glucose (HG)-induced injuries by inhibiting p38 mitogen-activated protein kinase (MAPK). Leptin induces hypertrophy in rat cardiomyocytes via p38/MAPK activation. The present study aimed to test the hypothesis that leptin-Janus kinase 2 (JAK2)/signal transducers and activators of transcription 3 (STAT3), which are responsible for leptin's functions, are involved in HG-induced injuries and cardioprotective effects of NRG in cardiomyocytes.

MATERIAL AND METHODS

H9c2 cells were exposed to HG for 24 h to establish a cardiomyocyte injury model. Cells were pretreated with NRG and other drugs before exposure to HG. Protein expression was measured by western blot analysis. Cell viability was detected by Cell Counting Kit-8 assay. Apoptotic cells were assessed by Hoechst 33258 staining assay. Intracellular reactive oxygen species levels were determined by dichlorofluorescein diacetate staining. Mitochondrial membrane potential was evaluated using JC-1. An enzyme-linked immunosorbent assay was performed to determine the inflammatory cytokines.

RESULTS

NRG significantly attenuated HG-induced increases in leptin and Ob-R expression. Pretreatment with either a leptin antagonist (LA) or NRG markedly ameliorated HG-induced elevation of phosphorylated (p)-JAK2 and p-STAT3, respectively. Pretreatment with NRG, LA, Ob-R antagonist, or AG490 clearly alleviated HG-induced injuries and inflammation.

CONCLUSIONS

This study provides new evidence of the NRG protective effects of H9c2 cells against HG-induced injuries possibly via modulation of the leptin-JAK2/STAT3 pathway.

Therapeutic potential of IKK-β inhibitors from natural phenolics for inflammation in cardiovascular diseases

Cardiovascular disease (CVDs) is a chronic disease with the highest morbidity and mortality in the world. Previous studies have suggested that preventing inflammation serves an efficient role in protection against cardiovascular diseases. Modulation of IKK-β activity can be used to treat and control CVDs associated with chronic inflammation, which targets the phosphorylation of IκB following the release of the RelA complex, and then translocates to the nucleus, eventually triggering the transcription of several genes that induce chemokines, cytokines, and adhesion molecules. Most importantly, the IκB kinase (IKK) complex is involved in transcriptional activation by phosphorylating the inhibitory molecule IkBα, enabling activation of NF-κB. Phenolic compounds possess cardioprotective potential that may be related to modulating inflammatory responses involved in CVDs. The SystemsDock analysis was used to explore whether 38 active compounds inhibit IKK-β activity based on literature. Docking results showed that the top docking score of three chemical compounds were icariin, salvianolic acid B, and plantainoside D in all compounds. Icariin, salvianolic acid B, and plantainoside D are the most promising IKKβ inhibitors. These phytochemicals could be helpful to find the lead compounds on designing and developing novel cardioprotective agents.

Naringenin improves mitochondrial function and reduces cardiac damage following ischemia-reperfusion injury: the role of the AMPK-SIRT3 signaling pathway

Mitochondrial dysfunction contributed greatly to myocardial ischemia-reperfusion (MI/R)-induced cardiomyocyte apoptosis. Naringenin is a flavonoid exhibiting potential protective effects on myocardial mitochondria under stress conditions. However, the detailed down-stream signaling pathway involved remains uncovered. This study was designed to elucidate naringenin's mitochondrial protective actions during MI/R with a focus on AMPK-SIRT3 signaling. Sprague-Dawley rats were administered with naringenin (50 mg kg-1 d-1) and subjected to MI/R surgery in the presence or absence of compound C (0.25 mg kg-1, Com.C, an AMPK inhibitor) co-treatment. An in vitro study was performed on H9c2 cardiomyoblasts subjected to simulated ischemia-reperfusion treatment. Before the treatment, the cells were administered with naringenin (80 μmol L-1) with or without SIRT3 siRNA/AMPK1α siRNA transfection. Naringenin improved post-reperfusion left ventricular systolic pressure and the instantaneous first derivative of left ventricular pressure, and reduced the infarction size and myocardial apoptosis index by suppressing mitochondrial oxidative stress damage (as evidenced by decreased mitochondrial cytochrome c release and oxidative markers) and enhancing mitochondrial biogenesis [as evidenced by increased NRF1, TFAM and oxidative phosphorylation subunit complexes (II, III and IV)]. These protective actions were abolished by Com.C (in vivo) or SIRT3 siRNA (in vitro) administration. Further investigation revealed that Com.C (in vivo) or AMPK1α siRNA (in vitro) markedly suppressed PGC-1α and SIRT3 levels while SIRT3 siRNA (in vitro) inhibited SIRT3 expression without significantly changing AMPK phosphorylation and PGC-1α levels. Taken together, we found that naringenin directly inhibits mitochondrial oxidative stress damage and preserves mitochondrial biogenesis, thus attenuating MI/R injury. Importantly, AMPK-SIRT3 signaling played a key role in this process.

Naringin mitigates myocardial strain and the inflammatory response in sepsis-induced myocardial dysfunction through regulation of PI3K/AKT/NF-κB pathway

Sepsis-induced myocardial dysfunction (SIMD) is a manifestation of severe sepsis and is the main cause of increased mortality in sepsis patients. Naringin (Nar) has been reported to possess various biological activities and pharmacological properties. Therefore, the present study was undertaken to evaluate whether Nar can protect rats from the effects of LPS-induced SIMD. SD Rats were pre-treated with Nar (50 and 100 mg/kg) for 7 days before administration of a single dose of LPS (10 mg/kg, i.p.) on the seventh day. We found that Nar treatment markedly improved the global strain and strain rate of longitudinal, circumference, and radial direction (GLS/GLSr, GCS/GCSr, GRS/GRSr) compared to the LPS group. The layer-specific strain decreased gradually from the endocardial layer to epicardial layer, and the most serious damage occurred in the endocardial layer. Moreover, Nar significantly decreased the levels of pro-inflammatory cytokines (TNF-α, IL-1β, and IL-6) and myocardial enzymes (CK, LDH, and AST) induced by LPS and attenuated the inflammation response. Finally, Nar also inhibited NF-κB nuclear translocation and the activity of iNOS in H9c2 cardiomyocytes by activating PI3K/AKT signaling pathway. These results suggest that naringin may possess novel therapeutic potential for protection against LPS-induced myocardial dysfunction.

Trolox prevents high glucose-induced apoptosis in rat myocardial H9c2 cells by regulating GLUT-4 and antioxidant defense mechanism

Redox imbalance due to hyperglycemia is a causative factor for an increased generation of reactive oxygen species (ROS) that leads to mitochondrial dysfunction and the release of cytochrome-c. The aim of the present study is to elucidate the functional role of oxidative stress (OS) in the induction of apoptosis in H9c2 cells in the hyperglycemic state through glucose transporter-4 (GLUT-4) regulation and antioxidant status. H9c2 cells were incubated with 15, 24, and 33 mM glucose for 24, 48, and 72 hr to induce hyperglycemic stress. Hyperglycemic episodes have significantly influenced GLUT-4 mRNA regulation, depleted glutathione (GSH) and its associated enzymes, reduced cellular antioxidant enzymes (AOEs), caused nuclear condensation, and induced apoptosis by activating caspase-9 and 3 and annexin V binding in a concentration and duration-dependent manner. Trolox pretreatment significantly enhanced the GLUT-4 mRNA and antioxidant defense mechanism, suppressed nuclear condensation, and prevented cytochrome-c release, thereby reducing mitochondrial-dependent apoptosis. The present study shows that the toxic effect of high glucose is significantly regulated and that OS induction can be prevented through a water-soluble vitamin E analog "Trolox" treatment.

Beneficial Effects of Citrus Flavonoids on Cardiovascular and Metabolic Health

The prevalence of cardiovascular disease (CVD) is increasing over time. CVD is a comorbidity in diabetes and contributes to premature death. Citrus flavonoids possess several biological activities and have emerged as efficient therapeutics for the treatment of CVD. Citrus flavonoids scavenge free radicals, improve glucose tolerance and insulin sensitivity, modulate lipid metabolism and adipocyte differentiation, suppress inflammation and apoptosis, and improve endothelial dysfunction. The intake of citrus flavonoids has been associated with improved cardiovascular outcomes. Although citrus flavonoids exerted multiple beneficial effects, their mechanisms of action are not completely established. In this review, we summarized recent findings and advances in understanding the mechanisms underlying the protective effects of citrus flavonoids against oxidative stress, inflammation, diabetes, dyslipidemia, endothelial dysfunction, and atherosclerosis. Further studies and clinical trials to assess the efficacy and to explore the underlying mechanism(s) of action of citrus flavonoids are recommended.

Preparation, characterization and in vitro and in vivo evaluation of a solid dispersion of Naringin

Naringin (NA) is one of typical flavanone glycosides widely distributed in nature and possesses several biological activities including antioxidant, anti-inflammatory, and antiapoptotic. The aim of this study was to develop solid dispersion (SD) and to improve the dissolution rate and oral bioavailability of NA. NA-SD was prepared by the traditional preparation methods using PEG6000, F68, or PVP K30 as carrier at different drug to carrier ratios. According to the results of solubility and in vitro dissolution test, the NA-PEG6000 (1:3) SD was considered as an optimal formulation to characterize by Fourier transform infrared spectroscopy (FT-IR), differential scanning calorimetry and powder X-ray diffraction. Furthermore, oral bioavailabilities of NA-PEG6000 (1:3) SD and NA-suspension with the same dosage were investigated in SD rats. The results confirmed the formation of SD and the pharmacokinetic parameters of NA-PEG6000 (1:3) SD (C_max = 0.645 ± 0.262 µg/ml, AUC_0-t = 0.471 ± 0.084 µg/ml h) were higher than that of NA-suspension (C_max = 0.328 ± 0.183 µg/ml, AUC_0-t  = 0.361 ± 0.093 µg/ml h). Based on the results, the SD is considered as a promising approach to enhance the dissolution rate and oral bioavailability of NA.

Mice pancreatic islets protection from oxidative stress induced by single-walled carbon nanotubes through naringin

The growing use of carbon nanotubes (CNTs) emphasizes the importance of its potential toxic effects on the human health. Previous studies proved that CNTs caused oxidative stress and decreased cell viability. On the other hand, reactive oxygen species (ROS) and oxidative stress impaired β-cell functions and reduced the insulin secretion. However, there is not any study on the effects of CNTs on islets and β-cells. Therefore, the present study aimed to evaluate the effects of single-walled CNTs (SWCNTs) on oxidative stress in islets in addition to the protective effects of naringin (NRG) as an antioxidant . We examined the effects of SWCNTs and naringin on islets by 3,4 3-(4,5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assay; measurement of insulin secretion, ROS, and malondialdehyde (MDA); activities of superoxide dismutase (SOD), catalase (CAT), and glutathione (GSH) peroxidase (GSH-Px); and content of GSH and mitochondrial membrane potential (MMP). The MTT assay demonstrated that decreased viability of islets cells was dose-dependent with exposure to SWCNTs. Further studies revealed that SWCNTs decreased insulin secretion and MMP, induced the formation of ROS, increased the level of MDA, and decreased the activities of SOD, GSH-Px, and CAT and content of GSH. Furthermore, the pretreatment of islets with naringin significantly reverted back these changes. These findings revealed that SWCNTs might induce the oxidative stress to pancreatic islets, causing the occurrence of diabetes, and the protective effects of naringin that was mediated by augmentation of the antioxidant defense system of islets. Our research indicated the necessity for further in vivo and in vitro researches on the effects of SWCNTs and naringin on diabetes.

High Glucose-Induced Cardiomyocyte Death May Be Linked to Unbalanced Branched-Chain Amino Acids and Energy Metabolism

High glucose-induced cardiomyocyte death is a common symptom in advanced-stage diabetic patients, while its metabolic mechanism is still poorly understood. The aim of this study was to explore metabolic changes in high glucose-induced cardiomyocytes and the heart of streptozotocin-induced diabetic rats by ¹H-NMR-based metabolomics. We found that high glucose can promote cardiomyocyte death both in vitro and in vivo studies. Metabolomic results show that several metabolites exhibited inconsistent variations in vitro and in vivo. However, we also identified a series of common metabolic changes, including increases in branched-chain amino acids (BCAAs: leucine, isoleucine and valine) as well as decreases in aspartate and creatine under high glucose condition. Moreover, a reduced energy metabolism could also be a common metabolic characteristic, as indicated by decreases in ATP in vitro as well as AMP, fumarate and succinate in vivo. Therefore, this study reveals that a decrease in energy metabolism and an increase in BCAAs metabolism could be implicated in high glucose-induced cardiomyocyte death.

Exogenous hydrogen sulfide promotes hepatocellular carcinoma cell growth by activating the STAT3-COX-2 signaling pathway

The effects of hydrogen sulfide (H₂S) on cancer are controversial. Our group previously demonstrated that exogenous H₂S promotes the development of cancer via amplifying the activation of the nuclear factor-κB signaling pathway in hepatocellular carcinoma (HCC) cells (PLC/PRF/5). The present study aimed to further investigate the hypothesis that exogenous H₂S promotes PLC/PRF/5 cell proliferation and migration, and inhibits apoptosis by activating the signal transducer and activator of transcription 3 (STAT3)-cyclooxygenase-2 (COX-2) signaling pathway. PLC/PRF/5 cells were treated with 500 µmol/l NaHS (a donor of H₂S) for 24 h. The expression levels of phosphorylated (p)-STAT3, STAT3, cleaved caspase-3 and COX-2 were measured by western blot assay. Cell viability was detected by Cell Counting kit-8 assay. Apoptotic cells were observed by Hoechst 33258 staining. The expression of STAT3 and COX-2 messenger RNA (mRNA) was detected by semiquantitative reverse transcription-polymerase chain reaction. The production of vascular endothelial growth factor (VEGF) was evaluated by ELISA. The results indicated that treatment of PLC/PRF/5 cells with 500 µmol/l NaHS for 24 h markedly increased the expression levels of p-STAT3 and STAT3 mRNA, leading to COX-2 and COX-2 mRNA overexpression, VEGF induction, decreased cleaved caspase-3 production, increased cell viability and migration, and decreased number of apoptotic cells. However, co-treatment of PLC/PRF/5 cells with 500 µmol/l NaHS and 30 µmol/l AG490 (an inhibitor of STAT3) or 20 µmol/l NS-398 (an inhibitor of COX-2) for 24 h significantly reverted the effects induced by NaHS. Furthermore, co-treatment of PLC/PRF/5 cells with 500 µmol/l NaHS and 30 µmol/l AG490 markedly decreased the NaHS-induced increase in the expression level of COX-2. By contrast, co-treatment of PLC/PRF/5 cells with 500 µmol/l NaHS and 20 µmol/l NS-398 inhibited the NaHS-induced increase in the expression level of p-STAT3. In conclusion, the findings of the present study provide evidence that the STAT3-COX-2 signaling pathway is involved in NaHS-induced cell proliferation, migration, angiogenesis and anti-apoptosis in PLC/PRF/5 cells, and suggest that the positive feedback between STAT3 and COX-2 may serve a crucial role in hepatocellular carcinoma carcinogenesis.

Therapeutic Potential of Polyphenols in Cardiac Fibrosis

Cardiac fibrosis, in response to injury and stress, is central to a broad constellation of cardiovascular diseases. Fibrosis decreases myocardial wall compliance due to extracellular matrix (ECM) accumulation, leading to impaired systolic and diastolic function and causing arrhythmogenesis. Although some conventional drugs, such as β-blockers and renin-angiotensin-aldosterone system (RAAS) inhibitors, have been shown to alleviate cardiac fibrosis in clinical trials, these traditional therapies do not tend to target all the fibrosis-associated mechanisms, and do not hamper the progression of cardiac fibrosis in patients with heart failure. Polyphenols are present in vegetables, fruits, and beverages and had been proposed as attenuators of cardiac fibrosis in different models of cardiovascular diseases. Together with results found in the literature, we can show that some polyphenols exert anti-fibrotic and myocardial protective effects by mediating inflammation, oxidative stress, and fibrotic molecular signals. This review considers an overview of the mechanisms of cardiac fibrosis, illustrates their involvement in different animal models of cardiac fibrosis treated with some polyphenols and projects the future direction and therapeutic potential of polyphenols on cardiac fibrosis.

Inhibition of miR-186-5p contributes to high glucose-induced injury in AC16 cardiomyocytes

A growing body of evidence has demonstrated that microRNAs (miRs) have pivotal roles in the pathophysiological development mechanisms of diabetic cardiomyopathy (DCM). Previous studies have demonstrated that miR-186-5p was significantly decreased in DCM. In addition, it has recently been reported that an imbalance of miR-186 is associated with a variety of physiological and pathological processes. Therefore, the present study was designed to investigate the role of miR-186-5p in high glucose (HG)-induced cytotoxicity and apoptosis in AC16 cardiomyocytes. Reverse transcription-polymerase chain reaction was used to demonstrate the significant decrease in the level of miR-186-5p in HG-treated AC16 cells (P<0.05). Subsequently, it was clarified that pre-transfection with miR-186-5p mimic significantly ameliorated the effects of high glucose, which induced a significant decrease in the viability of AC16 cells (P<0.05) and increases in apoptosis, as evidenced by the appearance of apoptotic nucleus and the significant upregulation of apoptosis rate in AC16 cells (P<0.05). In addition, the significantly increased expression of caspase-3 induced by HG (P<0.01) was also reversed by miR-186-5p mimic (P<0.01). Conversely, transfection with miR-186-5p inhibitor significantly reduced the viability of AC16 cells (P<0.05) and promoted apoptosis (P<0.05) as well as the expression of caspase-3 in AC16 cells (P<0.01), indicating the beneficial role of miR-186-5p in the physiological process of HG-induced damage. In conclusion, these results suggest that the distribution of miR-186-5p contributes to HG-induced cytotoxicity and apoptosis in AC16 cardiomyocytes.

Angiotensin-(1-7) protects cardiomyocytes against high glucose-induced injuries through inhibiting reactive oxygen species-activated leptin-p38 mitogen-activated protein kinase/extracellular signal-regulated protein kinase 1/2 pathways, but not the leptin-c-Jun N-terminal kinase pathway in vitro

Aims/Introduction

Angiotensin‐(1–7) (Ang‐[1–7]), recognized as a new bioactive peptide in the renin–angiotensin system, shows biological and pharmacological properties in diabetic cardiovascular diseases. The leptin‐induced p38 mitogen‐activated protein kinase (MAPK) pathway has been reported to contribute to high glucose (HG)‐induced injury. In the present study, we showed the mechanism of how Ang‐(1–7) can protect against HG‐stimulated injuries in H9c2 cells.

Materials and Methods

H9c2 cells were treated with 35 mmol/L glucose (HG) for 24 h to establish a model of HG‐induced damage. Apoptotic cells were observed by Hoechst 33258 staining. Cell viability was analyzed by cell counter kit‐8. The expression of protein was detected by western blot. Reactive oxygen species was tested by 2′,7′‐dichlorodihydrofluorescein diacetate staining. Mitochondrial membrane potential was measured by 5,5′,6,6′‐Tetrachloro‐1,1′,3,3′‐tetraethyl‐imidacarbocyanine iodide staining.

Results

The present results showed that treating H9c2 cells with HG obviously enhanced the expressions of both the leptin and phosphorylated (p)‐MAPK pathway. However, the overexpression levels of leptin and p‐p38 MAPK/p‐extracellular signal‐regulated protein kinase 1/2 (ERK1/2), but not p‐c‐Jun N‐terminal kinase, were significantly suppressed by treatment of the cells with Ang‐(1–7). Additionally, leptin antagonist also markedly suppressed the overexpressions of p38 and ERK1/2 induced by HG, whereas leptin antagonist had no influence on the overexpression of c‐Jun N‐terminal kinase. More remarkable, Ang‐(1–7), leptin antagonist, SB203580 or SP600125, respectively, significantly inhibited the injuries induced by HG, such as the increased cell viability, decreased apoptotic rate, reduction of ROS production and increased mitochondrial membrane potential. Furthermore, the overexpressions of p38 MAPK, ERK1/2 and leptin were suppressed by N‐actyl‐L‐cystine.

Conclusions

The present findings show that Ang‐(1–7) protects from HG‐stimulated damage as an inhibitor of the reactive oxygen species–leptin–p38 MAPK/ERK1/2 pathways, but not the leptin–c‐Jun N‐terminal kinase pathway in vitro.

Preparation and antitumor evaluation of self-assembling oleanolic acid-loaded Pluronic P105/d-α-tocopheryl polyethylene glycol succinate mixed micelles for non-small-cell lung cancer treatment

Oleanolic acid (OA) is a triterpenoid found in various fruits and vegetables and used in traditional Chinese medicine. OA plays a crucial role in the treatment of several cancers, but poor water solubility, low permeability, and significant efflux have limited its widespread clinical use. Vitamin E-d-α-tocopheryl polyethylene glycol succinate (vitamin E-TPGS) and Pluronic P105 were used to improve the solubility and permeability and to decrease the efflux of OA. OA-loaded mixed micelles were prepared by ethanol thin-film hydration. The physicochemical properties of the micelles, including zeta potential, morphology, particle size, solubility, drug loading, and drug entrapment efficiency were characterized. OA release from micelles was slower than that from the free drug system. OA uptake by A549 non-small-cell lung cancer (NSCLC) cells was enhanced by the micelles. A tumor model was established by injecting A549 cells into nude mice. In vivo imaging showed that OA-micelles could accumulate in the tumors of nude mice. Additionally, smaller tumor size and increased expression of pro-apoptotic proteins were observed in OA-micelle-treated mice, indicating that OA-micelles are more effective than free OA in treating cancer. In vitro experiments were performed using two NSCLC cell lines (A549 and PC-9). Cytotoxicity evaluations showed that the half-maximal inhibitory concentrations of free OA and OA-micelles were 36.8±4.8 and 20.9±3.7 μM, respectively, in A549 cells and 82.7±7.8 and 56.7±4.7 μM, respectively, in PC-9 cells. Apoptosis assays revealed that the apoptotic rate of OA-micelle-treated A549 and PC-9 cells was higher than that of cells treated with the same concentration of free OA. Wound healing and transwell assays showed that migration and invasion were significantly suppressed in OA-micelle-treated cells. Immunofluorescence and Western blot analyses confirmed that the epithelial–mesenchymal transition was reversed in OA-micelle-treated cells. Mixed micelles are a promising nano-drug delivery system for lung cancer treatment.