Empagliflozin Ameliorates Obesity-Related Cardiac Dysfunction by Regulating Sestrin2-Mediated AMPK-mTOR Signaling and Redox Homeostasis in High-Fat Diet-Induced Obese Mice

Sestrin2 knockout exacerbates high-fat diet induced metabolic disorders and complications in female mice

BACKGROUND

Obesity and its associated complications raise significant public concern, revealing gender disparities in the susceptibility to metabolic disorders, with females often displaying greater resistance to obesity-related metabolic disorder than males. Sestrin2 is a crucial protein involved in metabolism and energy balance. This study seeks to explore whether Sesn2 knockout (KO) exacerbates high-fat diet (HFD) induced obesity in female mice.

METHODS

Female mice with wild-type (WT) and Sesn2 KO were subjected to a 12-week regimen of normal diet or HFD. Using a Body Composition Analyzer, body composition was gauged. Biochemical assays encompassed glucose, lipid, and liver function measurements, alongside 24-hour urine albumin excretion. Echocardiographic evaluation assessed cardiac function. Histopathological analysis of key metabolic tissues (liver, kidney, and heart tissues) were conducted. Western blotting or qRT-PCR evaluated key proteins and genes linked to inflammation, mitochondrial, and lipid metabolism in adipose tissues.

RESULTS

In comparison to mice fed a regular diet, those on a HFD exhibited significant increases in body weight and fat mass. Notably, Sesn2 KO further aggravated obesity, showcasing the most pronounced metabolic anomalies: elevated body weight, fat mass, impaired glucose tolerance, and insulin sensitivity, alongside heightened levels of free fatty acids and triglycerides. Additionally, KO-HFD mice displayed exacerbated multi-tissue impairments, including elevated hepatic enzymes, increased urinary albumin excretion, compromised cardiac function, and accumulation of lipids in the liver, kidney, and heart. Moreover, adipose tissue showcased altered lipid dynamics and function, characterized by enhanced triglyceride breakdown and modified adipokine levels. Browning was diminished, along with decreased Pgc1α and Sirt1 in KO-HFD mice.

CONCLUSION

Sesn2 KO exacerbates HFD-induced obesity and metabolic disorders in female mice. These findings underscore Sestrin2's novel role as a regulator of obesity in female mice.

LDHA contributes to nicotine induced cardiac fibrosis through autophagy flux impairment

Cardiac fibrosis is a typical feature of cardiac pathological remodeling, which is associated with adverse clinical outcomes and has no effective therapy. Nicotine is an important risk factor for cardiac fibrosis, yet its underlying molecular mechanism remains poorly understood. This study aimed to identify its potential molecular mechanism in nicotine-induced cardiac fibrosis. Our results showed nicotine exposure led to the proliferation and transformation of cardiac fibroblasts (CFs) into myofibroblasts (MFs) by impairing autophagy flux. Through the use of drug affinity responsive target stability (DARTS) assay, cellular thermal shift assay (CETSA), and surface plasmon resonance (SPR) technology, it was discovered that nicotine directly increased the stability and protein levels of lactate dehydrogenase A (LDHA) by binding to it. Nicotine treatment impaired autophagy flux by regulating the AMPK/mTOR signaling pathway, impeding the nuclear translocation of transcription factor EB (TFEB), and reducing the activity of cathepsin B (CTSB). In vivo, nicotine treatment exacerbated cardiac fibrosis induced in spontaneously hypertensive rats (SHR) and worsened cardiac function. Interestingly, the absence of LDHA reversed these effects both in vitro and in vivo. Our study identified LDHA as a novel nicotine-binding protein that plays a crucial role in mediating cardiac fibrosis by blocking autophagy flux. The findings suggest that LDHA could potentially serve as a promising target for the treatment of cardiac fibrosis.

Evaluation of serum levels of sestrin 2 and betatrophin in type 2 diabetic patients with diabetic nephropathy

BACKGROUND

Diabetic kidney disease (DKD) is one of the most serious microvascular complications of diabetes mellitus (DM) and the leading cause of chronic kidney disease (CKD) worldwide. Since obesity and type 2 DM (T2DM) are considered as inflammatory conditions, thus reducing their accompanied systemic inflammation may lessen their complications. Sestrin 2 belongs to a group of stress induced proteins which are produced in response to oxidative stress, inflammation and DNA damage. Betatrophin; a hormone that stimulates the growth, proliferation and mass expansion of pancreatic beta-cells and improves glucose tolerance. The objective of the study was to evaluate levels of serum Sestrin 2 and betatrophin in patients with different stages of diabetic nephropathy (DN)) and compare results with healthy control.

METHODS

This cross sectional study was carried out on 60 patients above 18 years old, recruited from Tanta University hospitals out patients clinics and 20 apparently healthy individuals of matched sex and age as a control group. Participants were divided into two groups: group I: 20 normal subjects as control group and group II: 60 patients with type 2 DM,. further subdivided in to three equal groups: group 1IIA(20 patients) with normo-albuminuria (ACR < 30 mg/g), group IIB (20 patients) with micro albuminuria (ACR = 30 to 300 mg/g) and group IIC (20 patients) with macro albuminuria (ACR > 300 mg/g). They were subjected to detailed history taking, careful clinical examination and laboratory investigations including blood urea, serum creatinine, estimated glomerular filtration rate (eGFR), urinary albumin creatinine ratio, and specific laboratory tests for Sestrin 2 and Betatrophin by using ELISA technique.

RESULTS

Serum Sestrin 2 significantly decreased, while serum betatrophin level significantly increased in macroalbuminuric group compared to control and other 2 diabetic groups (P value < 0.05). The cut off value of serum sestrin 2 was 0.98 ng/ml with sensitivity 99%, specificity 66% while the cut off value of serum betatrophin was > 98.25 ng/ml with sensitivity 98%, specificity 82%. Serum betatrophin positively correlated with age, fasting, 2 h postprandial, BMI, triglyceride, total cholesterol, serum creatinine, blood urea, UACR, and negatively correlated with eGFR and serum albumin. Serum Sestrin 2 positively correlated with serum albumin. BMI, serum urea, UACR and serum albumin. Serum betatrophin are found to be risk factors or predictors for diabetic nephropathy.

CONCLUSIONS

Patients with DN, particularly the macroalbuminuria group, had a significant increase in betatrophin levels and a significant decrease in serum Sestrin 2 level. The function of Sestrin 2 is compromised in DN, and restoring it can reverse a series of molecular alterations with subsequent improvement of the renal functions, albuminuria and structural damage.

Mitochondrial glycerol 3-phosphate dehydrogenase deficiency exacerbates lipotoxic cardiomyopathy

Metabolic diseases such as obesity and diabetes induce lipotoxic cardiomyopathy, which is characterized by myocardial lipid accumulation, dysfunction, hypertrophy, fibrosis and mitochondrial dysfunction. Here, we identify that mitochondrial glycerol 3-phosphate dehydrogenase (mGPDH) is a pivotal regulator of cardiac fatty acid metabolism and function in the setting of lipotoxic cardiomyopathy. Cardiomyocyte-specific deletion of mGPDH promotes high-fat diet induced cardiac dysfunction, pathological hypertrophy, myocardial fibrosis, and lipid accumulation. Mechanically, mGPDH deficiency inhibits the expression of desuccinylase SIRT5, and in turn, the hypersuccinylates majority of enzymes in the fatty acid oxidation (FAO) cycle and promotes the degradation of these enzymes. Moreover, manipulating SIRT5 abolishes the effects of mGPDH ablation or overexpression on cardiac function. Finally, restoration of mGPDH improves lipid accumulation and cardiomyopathy in both diet-induced and genetic obese mouse models. Thus, our study indicates that targeting mGPDH could be a promising strategy for lipotoxic cardiomyopathy in the context of obesity and diabetes.

Empagliflozin, a sodium-glucose cotransporter inhibitor enhancing mitochondrial action and cardioprotection in metabolic syndrome

Metabolic syndrome (MetS) has a large clinical population nowadays, usually due to excessive energy intake and lack of exercise. During MetS, excess nutrients stress the mitochondria, resulting in relative hypoxia in tissues and organs, even when blood supply is not interrupted or reduced, making mitochondrial dysfunction a central pathogenesis of cardiovascular disease in the MetS. Sodium-glucose cotransporter 2 inhibitors were designed as a hyperglycemic drug that acts on the renal tubules to block sugar reabsorption in primary urine. Recently they have been shown to have anti-inflammatory and other protective effects on cardiomyocytes in MetS, and have also been recommended in the latest heart failure guidelines as a routine therapy. Among these inhibitors, empagliflozin shows better clinical promise due to less influence from glomerular filtration rate. This review focuses on the mitochondrial mechanisms of empagliflozin, which underlie the anti-inflammatory and recover cellular functions in MetS cardiomyocytes, including stabilizing calcium concentration, mediating metabolic reprogramming, maintaining homeostasis of mitochondrial quantity and quality, stable mitochondrial DNA copy number, and repairing damaged mitochondrial DNA.

Abnormal expression of PRKAG2-AS1 in endothelial cells induced inflammation and apoptosis by reducing PRKAG2 expression

PRKAG2 is required for the maintenance of cellular energy balance. PRKAG2-AS1, a long non-coding RNA (lncRNA), was found within the promoter region of PRKAG2. Despite the extensive expression of PRKAG2-AS1 in endothelial cells, the precise function and mechanism of this gene in endothelial cells have yet to be elucidated. The localization of PRKAG2-AS1 was predominantly observed in the nucleus, as revealed using nuclear and cytoplasmic fractionation and fluorescence in situ hybridization. The manipulation of PRKAG2-AS1 by knockdown and overexpression within the nucleus significantly altered PRKAG2 expression in a cis-regulatory manner. The expression of PRKAG2-AS1 and its target genes, PRKAG2b and PRKAG2d, was down-regulated in endothelial cells subjected to oxLDL and Hcy-induced injury. This finding suggests that PRKAG2-AS1 may be involved in the mechanism behind endothelial injury. The suppression of PRKAG2-AS1 specifically in the nucleus led to an upregulation of inflammatory molecules such as cytokines, adhesion molecules, and chemokines in endothelial cells. Additionally, this nuclear suppression of PRKAG2-AS1 facilitated the adherence of THP1 cells to endothelial cells. We confirmed the role of nuclear knockdown PRKAG2-AS1 in the induction of apoptosis and inhibition of cell proliferation, migration, and lumen formation through flow cytometry, TUNEL test, CCK8 assay, and cell scratching. Finally, it was determined that PRKAG2-AS1 exerts direct control over the transcription of PRKAG2 by its binding to their promoters. In conclusion, downregulation of PRKAG2-AS1 suppressed the proliferation and migration, promoted inflammation and apoptosis of endothelial cells, and thus contributed to the development of atherosclerosis resulting from endothelial cell injury.

Efficacy of dapagliflozin in improving arrhythmia-related outcomes after ablation for atrial fibrillation: a retrospective single-center study

BACKGROUND

Atrial fibrillation (AF) is a widespread type of sustained arrhythmia that poses significant health risks. Catheter ablation is the preferred treatment; however, arrhythmia recurrence remains challenging. Sodium-glucose co-transporter 2 inhibitors, particularly dapagliflozin (DAPA), have exhibited cardiovascular benefits. However, to date, the influence of these inhibitors on AF post-ablation remains unclear.

METHODS

We analyzed the records of 272 patients who underwent catheter ablation for AF from January 2018 to December 2022. Patients were divided into the control (n = 199) and DAPA (n = 73) groups based on DAPA prescription post-ablation. The primary outcome was total atrial arrhythmia recurrence after a 3-month blanking period.

RESULTS

The mean age was 72.19 ± 5.45 years; 86.8% of the patients were men. At 18 months post-ablation, 36.2% and 9.5% of the patients in the control and DAPA groups, respectively, reported atrial arrhythmia. Multivariate analysis revealed that DAPA use was associated with a significantly reduced risk of arrhythmia recurrence (adjusted hazard ratio [aHR]: 0.15, 95% confidence interval [CI]: 0.07-0.32, p < 0.001). After propensity score-matching (PSM) in 65 pairs, arrhythmia recurrence was lower in the DAPA group compared with the control (8.3% versus 30.8%, aHR: 0.17, 95% CI: 0.06-0.51, p = 0.002). Freedom from total arrhythmia recurrence was significantly higher in the DAPA group compared with the control group in both the overall and PSM population (log-rank test p < 0.01).

CONCLUSION

DAPA administration post-ablation was associated with significantly reduced atrial arrhythmia recurrence rates, indicating its potential as an adjunct therapy for enhancing the success of AF ablation.

Sestrin2 remedies neuroinflammatory response by inhibiting A1 astrocyte conversion via autophagy

Most central nervous diseases are accompanied by astrocyte activation. Autophagy, an important pathway for cells to protect themselves and maintain homeostasis, is widely involved in regulation of astrocyte activation. Reactive astrocytes may play a protective or harmful role in different diseases due to different phenotypes of astrocytes. It is an urgent task to clarify the formation mechanisms of inflammatory astrocyte phenotype, A1 astrocytes. Sestrin2 is a highly conserved protein that can be induced under a variety of stress conditions as a potential protective role in oxidative damage process. However, whether Sestrin2 can affect autophagy and involve in A1 astrocyte conversion is still uncovered. In this study, we reported that Sestrin2 and autophagy were significantly induced in mouse hippocampus after multiple intraperitoneal injections of lipopolysaccharide, with the elevation of A1 astrocyte conversion and inflammatory mediators. Knockdown Sestrin2 in C8-D1A astrocytes promoted the levels of A1 astrocyte marker C3 mRNA and inflammatory factors, which was rescued by autophagy inducer rapamycin. Overexpression of Sestrin2 in C8-D1A astrocytes attenuated A1 astrocyte conversion and reduced inflammatory factor levels via abundant autophagy. Moreover, Sestrin2 overexpression improved mitochondrial structure and morphology. These results suggest that Sestrin2 can suppress neuroinflammation by inhibiting A1 astrocyte conversion via autophagy, which is a potential drug target for treating neuroinflammation.

Targeting inflammatory signaling pathways with SGLT2 inhibitors: Insights into cardiovascular health and cardiac cell improvement

Sodium-glucose cotransporter 2 (SGLT2) inhibitors have attracted significant attention for their broader therapeutic impact beyond simply controlling blood sugar levels, particularly in their ability to influence inflammatory pathways. This review delves into the anti-inflammatory properties of SGLT2 inhibitors, with a specific focus on canagliflozin, empagliflozin, and dapagliflozin. One of the key mechanisms through which SGLT2 inhibitors exert their anti-inflammatory effects is by activating AMP-activated protein kinase (AMPK), a crucial regulator of both cellular energy balance and inflammation. Activation of AMPK by these inhibitors leads to the suppression of pro-inflammatory pathways and a decrease in inflammatory mediators. Notably, SGLT2 inhibitors have demonstrated the ability to inhibit the release of cytokines in an AMPK-dependent manner, underscoring their direct influence on inflammatory signaling. Beyond AMPK activation, SGLT2 inhibitors also modulate several other inflammatory pathways, including the NLRP3 inflammasome, expression of Toll-like receptor 4 (TLR-4), and activation of NF-κB (Nuclear factor kappa B). This multifaceted approach contributes to their efficacy in reducing inflammation and managing associated complications in conditions such as diabetes and cardiovascular disorders. Several human and animal studies provide support for the anti-inflammatory effects of SGLT2 inhibitors, demonstrating protective effects on various cardiac cells. Additionally, these inhibitors exhibit direct anti-inflammatory effects by modulating immune cells. Overall, SGLT2 inhibitors emerge as promising therapeutic agents for targeting inflammation in a range of pathological conditions. Further research, particularly focusing on the molecular-level pathways of inflammation, is necessary to fully understand their mechanisms of action and optimize their therapeutic potential in inflammatory diseases.

Immunotherapy targeting the obese white adipose tissue microenvironment: Focus on non-communicable diseases

Obesity triggers inflammatory responses in the microenvironment of white adipose tissue, resulting in chronic systemic inflammation and the subsequent development of non-communicable diseases, including type 2 diabetes, coronary heart disease, and breast cancer. Current therapy approaches for obesity-induced non-communicable diseases persist in prioritizing symptom remission while frequently overlooking the criticality of targeting and alleviating inflammation at its source. Accordingly, this review highlights the importance of the microenvironment of obese white adipose tissue and the promising potential of employing immunotherapy to target it as an effective therapeutic approach for non-communicable diseases induced by obesity. Additionally, this review discusses the challenges and offers perspective about the immunotherapy targeting the microenvironment of obese white adipose tissue.

Tectorigenin protects against cardiac fibrosis in diabetic mice heart via activating the adiponectin receptor 1-mediated AMPK pathway

Diabetic cardiomyopathy (DCM) is a common severe complication of diabetes that occurs independently of hypertension, coronary artery disease, and valvular cardiomyopathy, eventually leading to heart failure. Previous studies have reported that Tectorigenin (TEC) possesses extensive anti-inflammatory and anti-oxidative stress properties. In this present study, the impact of TEC on diabetic cardiomyopathy was examined. The model of DCM in mice was established with the combination of a high-fat diet and STZ treatment. Remarkably, TEC treatment significantly attenuated cardiac fibrosis and improved cardiac dysfunction. Concurrently, TEC was also found to mitigate hyperglycemia and hyperlipidemia in the DCM mouse. At the molecular level, TEC is involved in the activation of AMPK, both in vitro and in vivo, by enhancing its phosphorylation. This is achieved through the regulation of endothelial-mesenchymal transition via the AMPK/TGFβ/Smad3 pathway. Furthermore, it was demonstrated that the level of ubiquitination of the adiponectin receptor 1 (AdipoR1) protein is associated with TEC-mediated improvement of cardiac dysfunction in DCM mice. Notably the substantial reduction of myocardial fibrosis. In conclusion, TEC improves cardiac fibrosis in DCM mice by modulating the AdipoR1/AMPK signaling pathway. These findings suggest that TEC could be an effective therapeutic agent for the treatment of diabetic cardiomyopathy.

Redefining Diabetic Cardiomyopathy: Perturbations in Substrate Metabolism at the Heart of Its Pathology

Cardiovascular disease represents the leading cause of death in people with diabetes, most notably from macrovascular diseases such as myocardial infarction or heart failure. Diabetes also increases the risk of a specific form of cardiomyopathy, referred to as diabetic cardiomyopathy (DbCM), originally defined as ventricular dysfunction in the absence of underlying coronary artery disease and/or hypertension. Herein, we provide an overview on the key mediators of DbCM, with an emphasis on the role for perturbations in cardiac substrate metabolism. We discuss key mechanisms regulating metabolic dysfunction in DbCM, with additional focus on the role of metabolites as signaling molecules within the diabetic heart. Furthermore, we discuss the preclinical approaches to target these perturbations to alleviate DbCM. With several advancements in our understanding, we propose the following as a new definition for, or approach to classify, DbCM: "diastolic dysfunction in the presence of altered myocardial metabolism in a person with diabetes but absence of other known causes of cardiomyopathy and/or hypertension." However, we recognize that no definition can fully explain the complexity of why some individuals with DbCM exhibit diastolic dysfunction, whereas others develop systolic dysfunction. Due to DbCM sharing pathological features with heart failure with preserved ejection fraction (HFpEF), the latter of which is more prevalent in the population with diabetes, it is imperative to determine whether effective management of DbCM decreases HFpEF prevalence.

ARTICLE HIGHLIGHTS

The latest emerging drugs for the treatment of diabetic cardiomyopathy

INTRODUCTION

Diabetic cardiomyopathy (DCM) is a serious complication of diabetes mellitus involving multiple pathophysiologic mechanisms. In addition to hypoglycemic agents commonly used in diabetes, metabolism-related drugs, natural plant extracts, melatonin, exosomes, and rennin-angiotensin-aldosterone system are cardioprotective in DCM. However, there is a lack of systematic summarization of drugs for DCM.

AREAS COVERED

In this review, the authors systematically summarize the most recent drugs used for the treatment of DCM and discusses them from the perspective of DCM pathophysiological mechanisms.

EXPERT OPINION

We discuss DCM drugs from the perspective of the pathophysiological mechanisms of DCM, mainly including inflammation and metabolism. As a disease with multiple pathophysiological mechanisms, the combination of drugs may be more advantageous, and we have discussed some of the current studies on the combination of drugs.

SESN2-Mediated AKT/GSK-3β/NRF2 Activation to Ameliorate Adriamycin Cardiotoxicity in High-Fat Diet-Induced Obese Mice

Aims: Obese patients are highly sensitive to adriamycin (ADR)-induced cardiotoxicity. However, the potential mechanism of superimposed toxicity remains to be elucidated. Sestrin 2 (SESN2), a potential antioxidant, could attenuate stress-induced cardiomyopathy; therefore, this study aims to explore whether SESN2 enhances cardiac resistance to ADR-induced oxidative damage in high-fat diet (HFD)-induced obese mice. Results: The results revealed that obesity decreased SESN2 expression in ADR-exposed heart. And, HFD mice may predispose to ADR-induced cardiotoxicity, which was probably associated with inhibiting protein kinase B (AKT), glycogen synthase kinase-3 beta (GSK-3β) phosphorylation and subsequently blocking nuclear localization of nuclear factor erythroid-2 related factor 2 (NRF2), ultimately resulting in cardiac oxidative damage. However, these destructive cascades and cardiac oxidative damage effects induced by HFD/sodium palmitate combined with ADR were blocked by overexpression of SESN2. Moreover, the antioxidant effect of SESN2 could be largely abolished by sh-Nrf2 or wortmannin. And sulforaphane, an NRF2 agonist, could remarkably reverse cardiac pathological and functional abnormalities caused by ADR in obese mice. Innovation and Conclusion: This study demonstrated that SESN2 might be a promising therapeutic target for improving anthracycline-related cardiotoxicity in obesity by upregulating activity of NRF2 via AKT/GSK-3β/Src family tyrosine kinase signaling pathway. Antioxid. Redox Signal. 40, 598-615.

The Cardioprotective and Anticancer Effects of SGLT2 Inhibitors: JACC: CardioOncology State-of-the-Art Review

Sodium-glucose cotransporter-2 (SGLT2) inhibitors, originally approved for type 2 diabetes mellitus, have demonstrated efficacy in reducing cardiovascular events, particularly heart failure, in patients with and without diabetes. An intriguing research area involves exploring the potential application of SGLT2 inhibitors in cardio-oncology, aiming to mitigate the cardiovascular adverse events associated with anticancer treatments. These inhibitors present a unique dual nature, offering both cardioprotective effects and anticancer properties, conferring a double benefit for cardio-oncology patients. In this review, the authors first examine the established cardioprotective effects of SGLT2 inhibitors in heart failure and subsequently explore the existing body of evidence, including both preclinical and clinical studies, that supports the use of SGLT2 inhibitors in the context of cardio-oncology. The authors further discuss the mechanisms through which SGLT2 inhibitors protect against cardiovascular toxicity secondary to cancer treatment. Finally, they explore the potential anticancer effects of SGLT2 inhibitors along with their proposed mechanisms.

Elucidating the cardioprotective mechanisms of sodium-glucose cotransporter-2 inhibitors beyond glycemic control

Sodium-glucose cotransporter-2 (SGLT2) inhibitors have emerged as a pivotal intervention in diabetes management, offering significant cardiovascular benefits. Empagliflozin, in particular, has demonstrated cardioprotective effects beyond its glucose-lowering action, reducing heart failure hospitalizations and improving cardiac function. Of note, the cardioprotective mechanisms appear to be inde-pendent of glucose lowering, possibly mediated through several mechanisms involving shifts in cardiac metabolism and anti-fibrotic, anti-inflammatory, and anti-oxidative pathways. This editorial summarizes the multifaceted cardiovascular advantages of SGLT2 inhibitors, highlighting the need for further research to elucidate their full therapeutic potential in cardiac care.

Emerging role of antidiabetic drugs in cardiorenal protection

The global prevalence of diabetes mellitus (DM) has led to widespread multi-system damage, especially in cardiovascular and renal functions, heightening morbidity and mortality. Emerging antidiabetic drugs sodium-glucose cotransporter 2 inhibitors (SGLT2i), glucagon-like peptide-1 receptor agonists (GLP-1RAs), and dipeptidyl peptidase-4 inhibitors (DPP-4i) have demonstrated efficacy in preserving cardiac and renal function, both in type 2 diabetic and non-diabetic individuals. To understand the exact impact of these drugs on cardiorenal protection and underlying mechanisms, we conducted a comprehensive review of recent large-scale clinical trials and basic research focusing on SGLT2i, GLP-1RAs, and DPP-4i. Accumulating evidence highlights the diverse mechanisms including glucose-dependent and independent pathways, and revealing their potential cardiorenal protection in diabetic and non-diabetic cardiorenal disease. This review provides critical insights into the cardiorenal protective effects of SGLT2i, GLP-1RAs, and DPP-4i and underscores the importance of these medications in mitigating the progression of cardiovascular and renal complications, and their broader clinical implications beyond glycemic management.

Nrf2 prevents diabetic cardiomyopathy via antioxidant effect and normalization of glucose and lipid metabolism in the heart

Metabolic disorders and oxidative stress are the main causes of diabetic cardiomyopathy. Activation of nuclear factor erythroid 2-related factor 2 (Nrf2) exerts a powerful antioxidant effect and prevents the progression of diabetic cardiomyopathy. However, the mechanism of its cardiac protection and direct action on cardiomyocytes are not well understood. Here, we investigated in a cardiomyocyte-restricted Nrf2 transgenic mice (Nrf2-TG) the direct effect of Nrf2 on cardiomyocytes in DCM and its mechanism. In this study, cardiomyocyte-restricted Nrf2 transgenic mice (Nrf2-TG) were used to directly observe whether cardiomyocyte-specific overexpression of Nrf2 can prevent diabetic cardiomyopathy and correct glucose and lipid metabolism disorders in the heart. Compared to wild-type mice, Nrf2-TG mice showed resistance to diabetic cardiomyopathy in a streptozotocin-induced type 1 diabetes mouse model. This was primarily manifested as improved echocardiography results as well as reduced myocardial fibrosis, cardiac inflammation, and oxidative stress. These results showed that Nrf2 can directly act on cardiomyocytes to exert a cardioprotective role. Mechanistically, the cardioprotective effects of Nrf2 depend on its antioxidation activity, partially through improving glucose and lipid metabolism by directly targeting lipid metabolic pathway of AMPK/Sirt1/PGC-1α activation via upstream genes of sestrin2 and LKB1, and indirectly enabling AKT/GSK-3β/HK-Ⅱ activity via AMPK mediated p70S6K inhibition.

Sestrin 2 protects human lens epithelial cells from oxidative stress and apoptosis induced by hydrogen peroxide by regulating the mTOR/Nrf2 pathway

OBJECTIVE

We aimed to explore the effect and potential mechanism of Sestrin 2 (SESN2) in human lens epithelial cells (HLECs).

METHODS

To mimic the oxidative stress environment, SAR01/04 cells were treated with 200 μM hydrogen peroxide (H2O2) for 24 h. Cell viability and apoptosis were checked by cell counting kit-8 and flow cytometry. Western blot was taken to check the protein changes of SESN2, B-cell lymphoma-2 (Bcl-2), Bcl-2-associated X (Bax), mechanistic target of rapamycin (mTOR), phosphorylated (p)-mTOR, ribosomal protein S6 kinase B1 (p70S6K), p-p70S6K, and nuclear factor erythroid 2-related factor 2 (Nrf2). Superoxide dismutase (SOD), catalase (CAT), malondialdehyde (MDA), and reactive oxygen species (ROS) were detected via the corresponding reagent kit. The levels of interleukin (IL)-1β, IL-18, and tumor necrosis factor (TNF)-α were measured using enzyme-linked immunosorbent assay.

RESULTS

SESN2 was down-regulated in cataract lens tissue and up-regulated in SAR01/04 cells treated with H2O2. Under treatment of H2O2, up-regulation of SESN2 improved cell viability, enhanced the activity of SOD and CAT, inhibited cell apoptosis, and reduced the levels of MDA, ROS, IL-1β, IL-18, and TNF-α, while down-regulation of SESN2 caused the contrary effects. Further bioinformatics analysis suggested that SESN2 regulated the mTOR signaling pathway. Treatment of H2O2 inhibited p-mTOR and p-p70S6K protein expression, while overexpression of SESN2 increased p-mTOR and p-p70S6K protein expression in the H2O2 group and down-regulation of SESN2 further decreased p-mTOR and p-p70S6K protein expression in the H2O2 group. Additionally, H2O2 increased Nrf2 protein expression, and overexpression of SESN2 further increased Nrf2 protein expression in the H2O2 group. Importantly, rapamycin (an inhibitor of mTOR signaling pathway) and knockdown of Nrf2 reversed the promotive effects of SESN2 on cell viability and the inhibitive effects of SESN2 on cell apoptosis, oxidative stress, and inflammatory reaction.

CONCLUSION

SESN2 protected HLECs damage induced by H2O2, which was related to the activation of mTOR/Nrf2 pathway.

TorS - Reframing a rational for type 2 diabetes treatment

The mammalian target of rapamycin complex 1 syndrome (Tors), paradigm implies an exhaustive cohesive disease entity driven by a hyperactive mTORC1, and which includes obesity, type 2 diabetic hyperglycemia, diabetic dyslipidemia, diabetic cardiomyopathy, diabetic nephropathy, diabetic peripheral neuropathy, hypertension, atherosclerotic cardiovascular disease, non-alcoholic fatty liver disease, some cancers, neurodegeneration, polycystic ovary syndrome, psoriasis and other. The TorS paradigm may account for the efficacy of standard-of-care treatments of type 2 diabetes (T2D) in alleviating the glycaemic and non-glycaemic diseases of TorS in T2D and non-T2D patients. The TorS paradigm may generate novel treatments for TorS diseases.

GPER activation attenuates cardiac dysfunction by upregulating the SIRT1/3-AMPK-UCP2 pathway in postmenopausal diabetic rats

Postmenopausal diabetic women are at higher risk to develop cardiovascular diseases (CVD) compared with nondiabetic women. Alterations in cardiac cellular metabolism caused by changes in sirtuins are one of the main causes of CVD in postmenopausal diabetic women. Several studies have demonstrated the beneficial actions of the G protein-coupled estrogen receptor (GPER) in postmenopausal diabetic CVD. However, the molecular mechanisms by which GPER has a cardioprotective effect are still not well understood. In this study, we used an ovariectomized (OVX) type-two diabetic (T2D) rat model induced by high-fat diet/streptozotocin to investigate the effect of G-1 (GPER-agonist) on sirtuins, and their downstream pathways involved in regulation of cardiac metabolism and function. Animals were divided into five groups: Sham-Control, T2D, OVX+T2D, OVX+T2D+Vehicle, and OVX+T2D+G-1. G-1 was administrated for six weeks. At the end, hemodynamic factors were measured, and protein levels of sirtuins, AMP-activated protein kinase (AMPK), and uncoupling protein 2 (UCP2) were determined by Western blot analysis. In addition, cardiac levels of oxidative stress biomarkers were measured. The findings showed that T2D led to left ventricular dysfunction and signs of oxidative stress in the myocardium, which were accompanied by decreased protein levels of Sirt1/2/3/6, p-AMPK, and UCP2 in the heart. Moreover, the induction of the menopausal state exacerbated these changes. In contrast, treatment with G-1 ameliorated the hemodynamic changes associated with ovariectomy by increasing Sirt1/3, p-AMPK, UCP2, and improving oxidative status. The results provide evidence of the cardioprotective effects of GPER operating through Sirt1/3, p-AMPK, and UCP2, thereby improving cardiac function. Our results suggest that increasing Sirt1/3 levels may offer new therapeutic approaches for postmenopausal diabetic CVD.

Protective effect of empagliflozin against palmitate-induced lipotoxicity through AMPK in H9c2 cells

Sodium-glucose cotransporter 2 (SGLT2) inhibitors have recently emerged as novel cardioprotective agents. However, their direct impact on cardiomyocyte injury is yet to be studied. In this work, we investigate the underlying molecular mechanisms of empagliflozin (EMPA), an SGLT2 inhibitor, in mitigating palmitate (PA)-induced cardiomyocyte injury in H9c2 cells. We found that EMPA significantly attenuated PA-induced impairments in insulin sensitivity, ER stress, inflammatory cytokine gene expression, and cellular apoptosis. Additionally, EMPA elevated AMP levels, activated the AMPK pathway, and increased carnitine palmitoyl transferase1 (CPT1) gene expression, which collectively enhanced fatty acid oxidation and reduced stress signals. This study reveals a novel mechanism of EMPA's protective effects against PA-induced cardiomyocyte injury, providing new therapeutic insights into EMPA as a cardioprotective agent.

The link between obesity and aging - insights into cardiac energy metabolism

Obesity and aging are well-established risk factors for a range of diseases, including cardiovascular diseases and type 2 diabetes. Given the escalating prevalence of obesity, the aging population, and the subsequent increase in cardiovascular diseases, it is crucial to investigate the underlying mechanisms involved. Both aging and obesity have profound effects on the energy metabolism through various mechanisms, including metabolic inflexibility, altered substrate utilization for energy production, deregulated nutrient sensing, and mitochondrial dysfunction. In this review, we aim to present and discuss the hypothesis that obesity, due to its similarity in changes observed in the aging heart, may accelerate the process of cardiac aging and exacerbate the clinical outcomes of elderly individuals with obesity.

The promotion of sestrin2/AMPK signaling by HIF-1α overexpression enhances the damage caused by acute myocardial infarction

OBJECTIVE

Acute myocardial infarction (AMI), is a serious form of coronary heart disease. The present study sought to investigate the impact of HIF-1α on AMI, along with its fundamental mechanism.

METHODS

Sprague-Dawley (SD) rats were used to conduct an AMI model. 2,3,5-triphenyl-2H-tetrazolium chloride (TTC) staining was used examine the region of myocardial infract area at various time intervals. Protein expression levels were detected using western blotting. The rats were randomly divided into sham, model, negative control (NC), HIF-1α overexpression (HIF-1α-OE), and HIF-1α-OE+ si-sestrin2 groups. We examined the impact of HIF-1α overexpression on AMI rats using Haematoxylin-Eosin (H&E) staining, TTC staining, enzyme-linked immunosorbent assay (ELISA), TdT-mediated dUTP Nick-End Labeling (TUNEL) assay, and immunohistochemistry (IHC) staining.

RESULTS

According to the TTC findings, the region affected by myocardial infarction reached its peak at day 14. Based on the results from the western blot analysis, the levels of HIF-1α and sestrin2 were found the minimum on day 28. Subsequently, we discovered that the overexpression of HIF-1α rescued the cardiac function parameters, improved the morphology of myocardial tissue, and mitigated inflammation. Furthermore, the overexpression of HIF-1α led to a reduction in the levels of MDA and an increase in the levels of SOD. Moreover, the overexpression of HIF-1α resulted in a decrease in cellular apoptosis. This result was confirmed by the expression levels of Bcl-2 and Bax. Nevertheless, the defensive impact of elevated HIF-1α expression was somewhat counteracted by the suppression of sestrin2. In terms of mechanism, the overexpression of HIF-1α enhanced the levels of sestrin2 and the protein adenosine monophosphate activated kinase (AMPK).

CONCLUSION

Our research suggests that the overexpression of HIF-1α may rescue the damage to myocardial tissue, and this effect is associated with the sestrin2/AMPK signaling pathway. Our study provides a novel comprehension of the protective effects of HIF-1α overexpression on AMI.

Transforming growth factor-β and bone morphogenetic protein signaling pathways in pathological cardiac hypertrophy

Pathological cardiac hypertrophy (referred to as cardiac hypertrophy) is a maladaptive response of the heart to a variety of pathological stimuli, and cardiac hypertrophy is an independent risk factor for heart failure and sudden death. Currently, the treatments for cardiac hypertrophy are limited to improving symptoms and have little effect. Elucidation of the developmental process of cardiac hypertrophy at the molecular level and the identification of new targets for the treatment of cardiac hypertrophy are crucial. In this review, we summarize the research on multiple active substances related to the pathogenesis of cardiac hypertrophy and the signaling pathways involved and focus on the role of transforming growth factor-β (TGF-β) and bone morphogenetic protein (BMP) signaling in the development of cardiac hypertrophy and the identification of potential targets for molecular intervention. We aim to identify important signaling molecules with clinical value and hope to help promote the precise treatment of cardiac hypertrophy and thus improve patient outcomes.

chi-miR-130b-3p regulates the ZEA-induced oxidative stress damage through the KEAP1/NRF2 signaling pathway by targeting SESN2 in goat GCs

As a dominant mycotoxin, zearalenone (ZEA) has attracted extensive attention due to its estrogen-like effect and oxidative stress damage in cells. In order to find a way to relieve cell oxidative stress damage caused by ZEA, we treated goat granulosa cells (GCs) with ZEA and did a whole transcriptome sequencing. The results showed that the expression level of Sesterin2 (SESN2) was promoted extremely significantly in the ZEA group (p < .01). In addition, our research demonstrated that SESN2 could regulate oxidative stress level in GCs through Recombinant Kelch Like ECH Associated Protein 1 (KEAP1)/Nuclear factor erythroid 2-related factor 2 (NRF2) signaling pathway. The overexpression of SESN2 could reduce the oxidative damage, whereas knockdown of SESN2 would aggravate the oxidative damage caused by ZEA. What's more, microRNA (miRNA) chi-miR-130b-3p can bind to SESN2 3'-untranslated region (3'UTR) to regulate the expression of SESN2. The mimics/inhibition of chi-miR-130b-3p would have an effect on oxidative damage triggered by ZEA in GCs as well. In summary, these results elucidate a new pathway by which chi-miR-130b-3p affects the KEAP1/NRF2 pathway in GCs by modulating SESN2 expression in response to ZEA-induced oxidative stress damage.

Sestrin2 in diabetes and diabetic complications

Diabetes is a global health problem which is accompanied with multi-systemic complications. It is of great significance to elucidate the pathogenesis and to identify novel therapies of diabetes and diabetic complications. Sestrin2, a stress-inducible protein, is primarily involved in cellular responses to various stresses. It plays critical roles in regulating a series of cellular events, such as oxidative stress, mitochondrial function and endoplasmic reticulum stress. Researches investigating the correlations between Sestrin2, diabetes and diabetic complications are increasing in recent years. This review incorporates recent findings, demonstrates the diverse functions and regulating mechanisms of Sestrin2, and discusses the potential roles of Sestrin2 in the pathogenesis of diabetes and diabetic complications, hoping to highlight a promising therapeutic direction.

mTORC1 and SGLT2 Inhibitors-A Therapeutic Perspective for Diabetic Cardiomyopathy

Diabetic cardiomyopathy is a critical diabetes-mediated co-morbidity characterized by cardiac dysfunction and heart failure, without predisposing hypertensive or atherosclerotic conditions. Metabolic insulin resistance, promoting hyperglycemia and hyperlipidemia, is the primary cause of diabetes-related disorders, but ambiguous tissue-specific insulin sensitivity has shed light on the importance of identifying a unified target paradigm for both the glycemic and non-glycemic context of type 2 diabetes (T2D). Several studies have indicated hyperactivation of the mammalian target of rapamycin (mTOR), specifically complex 1 (mTORC1), as a critical mediator of T2D pathophysiology by promoting insulin resistance, hyperlipidemia, inflammation, vasoconstriction, and stress. Moreover, mTORC1 inhibitors like rapamycin and their analogs have shown significant benefits in diabetes and related cardiac dysfunction. Recently, FDA-approved anti-hyperglycemic sodium-glucose co-transporter 2 inhibitors (SGLT2is) have gained therapeutic popularity for T2D and diabetic cardiomyopathy, even acknowledging the absence of SGLT2 channels in the heart. Recent studies have proposed SGLT2-independent drug mechanisms to ascertain their cardioprotective benefits by regulating sodium homeostasis and mimicking energy deprivation. In this review, we systematically discuss the role of mTORC1 as a unified, eminent target to treat T2D-mediated cardiac dysfunction and scrutinize whether SGLT2is can target mTORC1 signaling to benefit patients with diabetic cardiomyopathy. Further studies are warranted to establish the underlying cardioprotective mechanisms of SGLT2is under diabetic conditions, with selective inhibition of cardiac mTORC1 but the concomitant activation of mTORC2 (mTOR complex 2) signaling.

Biochemical and histopathological evidence for beneficial effects of Empagliflozin pretreatment on acetic acid-induced colitis in rats

BACKGROUND

Ulcerative Colitis (UC) is a disorder which oxidative stress plays a critical role in its pathogenesis. Empagliflozin (EMPA) is a sodium-glucose cotransporter-2 (SGLT2) inhibitor that has been shown to have anti-inflammatory and antioxidative effects. The aim of this study was to investigate the protective effects of EMPA on acetic acid (AA) induced colitis in rats.

METHODS

A total of twenty-four rats were divided into four groups (six animals in each group) as follows: (1) Control group; (2) acetic acid (AA)-induced colitis group (AA); (3) EMPA treatment group (AA + EMPA); (4) Dexamethasone (Dexa) treatment group (AA + Dexa). Animals in pre-treatment groups received EMPA (10 mg/kg, i.p.) or dexamethasone (4 mg/kg, i.p. as reference drug) for four consecutive days before induction of colitis by intra-rectal acetic acid (4% v/v) administration. Twenty-four hours after AA administration, rats were sacrificed and the colon tissues were removed for histopathological and biochemical evaluations.

RESULTS

Pretreatment with EMPA significantly decreased colon weight/length ratio (81.00 ± 5.28 mg/cm vs. 108.80 ± 5.51 mg/cm) as well as, macroscopic (2.50 ± 0.57 vs. 3.75 ± 0.25) and histological scores (3.3 ± 0.14 vs. 1.98 ± 0.14) compared to the AA-induced colitis group (p < 0.01). Pretreatment with EMPA significantly reduced malondialdehyde (MDA) (324.0 ± 15.93 vs. 476.7 ± 32.26 nmol/mg p < 0.001) and increased glutathione level (117.5 ± 4.48 vs. 94.38 ± 3.950 µmol/mg, p < 0.01) in comparison to the AA-induced colitis group. Furthermore, a significant increase in catalase (44.60 ± 4.02 vs.14.59 ± 2.03 U/mg, P < 0.01), superoxide dismutase (283.9 ± 18.11 vs. 156.4 ± 7.92 U/mg, p < 0.001), and glutathione peroxidase (10.38 ± 1.45 vs. 2.508 ± 0.37, p < 0.01) activities were observed by EMPA pretreatment when compared to the AA-induced colitis group. These results were in line with those of the reference drug.

CONCLUSIONS

It is concluded that EMPA could effectively reduce the severity of tissue injury in experimental colitis. This protective effect may be related to the antioxidative effects of EMPA drug.

Role of dysfunctional peri-organ adipose tissue in metabolic disease

Metabolic disease is a complex disorder defined by a group with interrelated factors. There is growing evidence that obesity can lead to a variety of metabolic diseases, including diabetes and cardiovascular disease. Excessive adipose tissue (AT) deposition and ectopic accumulation can lead to increased peri-organ AT thickness. Dysregulation of peri-organ (perivascular, perirenal, and epicardial) AT is strongly associated with metabolic disease and its complications. The mechanisms include secretion of cytokines, activation of immunocytes, infiltration of inflammatory cells, involvement of stromal cells, and abnormal miRNA expression. This review discusses the associations and mechanisms by which various types of peri-organ AT affect metabolic diseases while addressing it as a potential future treatment strategy.

Immunomodulatory Effects of SGLT2 Inhibitors-Targeting Inflammation and Oxidative Stress in Aging

Given that the increase in the aging population has grown into one of the largest public health issues, inflammation and oxidative stress, which are closely associated with the aging process, became a focus of recent research. Sodium-glucose co-transporter 2 (SGLT2) inhibitors, a group of drugs initially developed as oral antidiabetics, have shown many beneficial effects over time, including improvement in renal function and cardioprotective effects. It has been shown that SGLT2 inhibitors, as a drug class, have an immunomodulatory and antioxidative effect, affecting endothelial function as well as metabolic parameters. Therefore, it is not surprising that various studies have investigated the potential mechanisms of action of SGLT2 inhibitors in age-related diseases. The proposed mechanisms by which SGLT2 inhibitors can achieve their anti-inflammatory effects include influence on AMPK/SIRT1/PGC-1α signaling, various cytokines, and the NLRP3 inflammasome. The antioxidative effect is related to their action on mitochondria and their influence on the signaling pathways of transforming growth factor β and nuclear erythroid 2-related factor 2/antioxidant response element. Also, SGLT2 inhibitors achieve their anti-inflammatory and antioxidative effects by affecting metabolic parameters, such as uric acid reduction, stimulation of ketogenesis, reduction of body weight, lipolysis, and epicardial fat tissue. Finally, SGLT2 inhibitors display anti-atherosclerotic effects that modulate inflammatory reactions, potentially resulting in improvement in endothelial function. This narrative review offers a complete and comprehensive overview of the possible pathophysiologic mechanisms of the SGLT2 inhibitors involved in the aging process and development of age-related disease. However, in order to use SGLT2 inhibitor drugs as an anti-aging therapy, further basic and clinical research is needed to elucidate the potential effects and complex mechanisms they have on inflammation processes.

Promising small molecule anti-fibrotic agents: Newly developed or repositioned drugs targeting myofibroblast transdifferentiation

Fibrosis occurs in all organs and tissues except the brain, and its progression leads to dysfunction of affected organs. Fibrosis-induced organ dysfunction results from the loss of elasticity, strength, and functionality of tissues due to the extracellular matrix secreted by myofibroblasts that express smooth muscle-type actin as a marker. Myofibroblasts, which play a major role in fibrosis, were once thought to originate exclusively from activated fibroblasts; however, it is now clear that myofibroblasts are diverse in origin, from epithelial cells, endothelial cells, adipocytes, macrophages, and other cells. Fibrosis of vital organs, such as the heart, lungs, kidneys, and liver, is a serious chronic disease that ultimately leads to death. Currently, anti-cancer drugs have made remarkable progress, as evidenced by the development of many molecular-targeted drugs, and are making a significant contribution to improving the prognosis of cancer treatment. However, the development of anti-fibrotic agents, which also play an important role in prognosis, has lagged. In this review, the current knowledge regarding myofibroblasts is summarized, with particular attention given to their origin and transdifferentiation signaling pathways (e.g., TGF-β, Wnt/β-catenin, YAP/TAZ and AMPK signaling pathways). The development of new small molecule anti-fibrotic agents and the repositioning of existing drugs targeting myofibroblast transdifferentiation are discussed.

Repurposing Drugs for Diabetes Mellitus as Potential Pharmacological Treatments for Sarcopenia - A Narrative Review

Sarcopenia, the age-related loss of muscle strength and mass or quality, is a common condition with major adverse consequences. Although the pathophysiology is incompletely understood, there are common mechanisms between sarcopenia and the phenomenon of accelerated ageing seen in diabetes mellitus. Drugs currently used to treat type 2 diabetes mellitus may have mechanisms of action that are relevant to the prevention and treatment of sarcopenia, for those with type 2 diabetes and those without diabetes. This review summarises shared pathophysiology between sarcopenia and diabetes mellitus, including the effects of advanced glycation end products, mitochondrial dysfunction, chronic inflammation and changes to the insulin signalling pathway. Cellular and animal models have generated intriguing, albeit mixed, evidence that supports possible beneficial effects on skeletal muscle function for some classes of drugs used to treat diabetes, including metformin and SGLT2 inhibitors. Most human observational and intervention evidence for the effects of these drugs has been derived from populations with type 2 diabetes mellitus, and there is a need for intervention studies for older people with, and at risk of, sarcopenia to further investigate the balance of benefit and risk in these target populations. Not all diabetes treatments will be safe to use in those without diabetes because of variable side effects across classes. However, some agents [including glucagon-like peptide (GLP)-1 receptor agonists and SGLT2 inhibitors] have already demonstrated benefits in populations without diabetes, and it is these agents, along with metformin, that hold out the most promise for further investigation in sarcopenia.

Empagliflozin Attenuates Vascular Calcification in Mice with Chronic Kidney Disease by Regulating the NFR2/HO-1 Anti-Inflammatory Pathway through AMPK Activation

Vascular calcification (VC) is associated with increased cardiovascular risks in patients with chronic kidney disease (CKD). Sodium-glucose cotransporter 2 inhibitors, such as empagliflozin, can improve cardiovascular and renal outcomes. We assessed the expression of Runt-related transcription factor 2 (Runx2), interleukin (IL)-1β, IL-6, AMP-activated protein kinase (AMPK), nuclear factor erythroid-2-related factor (Nrf2), and heme oxygenase 1 (HO-1) in inorganic phosphate-induced VC in mouse vascular smooth muscle cells (VSMCs) to investigate the mechanisms underlying empagliflozin's therapeutic effects. We evaluated biochemical parameters, mean artery pressure (MAP), pulse wave velocity (PWV), transcutaneous glomerular filtration rate (GFR), and histology in an in vivo mouse model with VC induced by an oral high-phosphorus diet following a 5/6 nephrectomy in ApoE^-/- mice. Compared to the control group, empagliflozin-treated mice showed significant reductions in blood glucose, MAP, PWV, and calcification, as well as increased calcium and GFR levels. Empagliflozin inhibited osteogenic trans-differentiation by decreasing inflammatory cytokine expression and increasing AMPK, Nrf2, and HO-1 levels. Empagliflozin mitigates high phosphate-induced calcification in mouse VSMCs through the Nrf2/HO-1 anti-inflammatory pathway by activating AMPK. Animal experiments suggested that empagliflozin reduces VC in CKD ApoE^-/- mice on a high-phosphate diet.

Empagliflozin Ameliorates Bleomycin-Induced Pulmonary Fibrosis in Rats by Modulating Sesn2/AMPK/Nrf2 Signaling and Targeting Ferroptosis and Autophagy

Pulmonary fibrosis (PF) is a life-threatening disorder that severely disrupts normal lung architecture and function, resulting in severe respiratory failure and death. It has no definite treatment. Empagliflozin (EMPA), a sodium-glucose cotransporter 2 (SGLT2) inhibitor, has protective potential in PF. However, the mechanisms underlying these effects require further elucidation. Therefore, this study aimed to evaluate the ameliorative effect of EMPA against bleomycin (BLM)-induced PF and the potential mechanisms. Twenty-four male Wister rats were randomly divided into four groups: control, BLM treated, EMPA treated, and EMPA+BLM treated. EMPA significantly improved the histopathological injuries illustrated by both hematoxylin and eosin and Masson's trichrome-stained lung tissue sections, as confirmed by electron microscopic examination. It significantly reduced the lung index, hydroxyproline content, and transforming growth factor β1 levels in the BLM rat model. It had an anti-inflammatory effect, as evidenced by a decrease in the inflammatory cytokines' tumor necrosis factor alpha and high mobility group box 1, inflammatory cell infiltration into the bronchoalveolar lavage fluid, and the CD68 immunoreaction. Furthermore, EMPA mitigated oxidative stress, DNA fragmentation, ferroptosis, and endoplasmic reticulum stress, as evidenced by the up-regulation of nuclear factor erythroid 2-related factor expression, heme oxygenase-1 activity, glutathione peroxidase 4 levels, and a decrease in C/EBP homologous protein levels. This protective potential could be explained on the basis of autophagy induction via up-regulating lung sestrin2 expression and the LC3 II immunoreaction observed in this study. Our findings indicated that EMPA protected against BLM-induced PF-associated cellular stress by enhancing autophagy and modulating sestrin2/adenosine monophosphate-activated protein kinase/nuclear factor erythroid 2-related factor 2/heme oxygenase 1 signaling.

Canagliflozin Ameliorates Oxidative Stress and Autistic-like Features in Valproic-Acid-Induced Autism in Rats: Comparison with Aripiprazole Action

Based on their proven anti-inflammatory and antioxidant effects, recent studies have examined the therapeutic potential of the sodium-glucose cotransporter 2 (SGLT2) inhibitors in neurodevelopmental disorders such as autism spectrum disorder (ASD). Therefore, the aim of this study is to assess the effects of subchronic systemic treatment with intraperitoneal (i.p.) canagliflozin (20, 50, and 100 mg/kg) compared to aripiprazole (ARP) (3 mg/g, i.p.) in a valproic acid (VPA)-induced rat model of autism. The behavioral characteristics of ASD, oxidative stress, and acetylcholinesterase (AChE) activity in rats with ASD-like behaviors, which were induced by prenatal exposure to VPA, were evaluated. The behavioral assessment methods used for this study were the open field test (OFT), the marble-burying test (MBT), and the nestlet-shredding test (NST) to examine their exploratory, anxiety, and compulsiveness-like actions, while the biochemical assessment used for this study was an ELISA colorimetric assay to measure ASD biomarker activity in the hippocampus, prefrontal cortex, and cerebellum. Rats that were pretreated with 100 mg/kg of canagliflozin displayed a significantly lower percentage of shredding (1.12 ± 0.6%, p < 0.01) compared to the ARP group (3.52 ± 1.6%). Pretreatment with (20 mg/kg, 50 mg/kg, and 100 mg/kg) canagliflozin reversed anxiety levels and hyperactivity and reduced hyper-locomotor activity significantly (161 ± 34.9 s, p < 0.05; 154 ± 44.7 s, p < 0.05; 147 ± 33.6 s, p < 0.05) when compared with the VPA group (303 ± 140 s). Moreover, canagliflozin and ARP mitigated oxidative stress status by restoring levels of glutathione (GSH) and catalase (CAT) and increasing the levels of malondialdehyde (MDA) in all tested brain regions. The observed results propose repurposing of canagliflozin in the therapeutic management of ASD. However, further investigations are still required to verify the clinical relevance of canagliflozin in ASD.

Empagliflozin ameliorates diabetic cardiomyopathy via regulated branched-chain amino acid metabolism and mTOR/p-ULK1 signaling pathway-mediated autophagy

BACKGROUND

Empagliflozin, a sodium-glucose co-transporter 2 inhibitor (SGLT2i), has been reported to significantly reduce the risk of heart failure in multiple clinical studies. However, the underlying mechanisms remain elusive. This study aimed to investigate the effect of empagliflozin on branched-chain amino acid (BCAA) metabolism in diabetic cardiomyopathy.

METHODS

Thirty male 8-week KK Cg-Ay/J mice were used to study diabetic cardiomyopathy; here, 15 were used as the model group, and the remaining 15 were administered empagliflozin (3.75 mg/kg/day) by gavage daily for 16 weeks. The control group consisted of fifteen male 8-week C57BL/6J mice, whose blood glucose and body weight were measured simultaneously with the diabetic mice until 16 weeks without additional intervention. Echocardiography and histopathology were performed to evaluate cardiac structure and function. Proteomic sequencing and biogenic analysis were performed on mouse hearts. Parallel Reaction Monitoring and western blotting were performed to validate the expression levels of differentially expressed proteins.

RESULTS

The results showed that empagliflozin improved ventricular dilatation and ejection fraction reduction in diabetic hearts, as well as the elevation of myocardial injury biomarkers hs-cTnT and NT-proBNP. At the same time, empagliflozin alleviates myocardial inflammatory infiltration, calcification foci deposition, and fibrosis caused by diabetes. The results of the proteomics assay showed that empagliflozin could improve the metabolism of various substances, especially promoting the BCAA metabolism of diabetic hearts by up-regulating PP2Cm. Furthermore, empagliflozin could affect the mTOR/p-ULK1 signaling pathway by reducing the concentration of BCAA in diabetic hearts. When mTOR/p-ULK1 protein was inhibited, ULK1, the autophagy initiation molecule, increased. Moreover, autophagy substrate p62 and autophagy marker LC3B were significantly reduced, indicating that the autophagy activity of diabetes inhibition was reactivated.

CONCLUSIONS

Empagliflozin may attenuate diabetic cardiomyopathy-related myocardial injury by promoting the catabolism of BCAA and inhibiting mTOR/p-ULK1 to enhance autophagy. These findings suggest that empagliflozin could be a potential candidate drug against BCAA increase and could be used for other cardiovascular diseases with a metabolic disorder of BCAA.

New insights into the molecular mechanisms of SGLT2 inhibitors on ventricular remodeling

Ventricular remodeling is a pathological process of ventricular response to continuous stimuli such as pressure overload, ischemia or ischemia-reperfusion, which can lead to the change of cardiac structure and function structure, which is central to the pathophysiology of heart failure (HF) and is an established prognostic factor in patients with HF. Sodium glucose cotransporter 2 inhibitors (SGLT2i) get a new hypoglycemic drug that inhibit sodium glucose coconspirator on renal tubular epithelial cells. Recently, clinical trials increasingly and animal experiments increasingly have shown that SGLT2 inhibitors have been largely applied in the fields of cardiovascular diseases, forinstance heart failure, myocardial ischemia-reperfusion injury, myocardial infarction, atrial fibrillation, metabolic diseases such as obesity, diabetes cardiomyopathy and other diseases play a cardiovascular protective role in addition to hypoglycemic. These diseases are association with ventricular remodeling. Inhibiting ventricular remodeling can improve the readmission rate and mortality of patients with heart failure. So far, clinical trials and animal experiments demonstrate that the protective effect of SGLT2 inhibitors in the cardiovascular field is bound to inhibit ventricular remodeling. Therefore, this review briefly investigates the molecular mechanisms of SGLT2 inhibitors on ameliorating ventricular remodeling, and further explore the mechanisms of cardiovascular protection of SGLT2 inhibitors, in order to establish strategies for ventricular remodeling to prevent the progress of heart failure.

An Overview of the Cardioprotective Effects of Novel Antidiabetic Classes: Focus on Inflammation, Oxidative Stress, and Fibrosis

Metabolic diseases, particularly diabetes mellitus (DM), are significant global public health concerns. Despite the widespread use of standard-of-care therapies, cardiovascular disease (CVD) remains the leading cause of death among diabetic patients. Early and evidence-based interventions to reduce CVD are urgently needed. Large clinical trials have recently shown that sodium-glucose cotransporter-2 inhibitors (SGLT2i) and glucagon-like peptide-1 receptor agonists (GLP-1RA) ameliorate adverse cardiorenal outcomes in patients with type 2 DM. These quite unexpected positive results represent a paradigm shift in type 2 DM management, from the sole importance of glycemic control to the simultaneous improvement of cardiovascular outcomes. Moreover, SGLT2i is also found to be cardio- and nephroprotective in non-diabetic patients. Several mechanisms, which may be potentially independent or at least separate from the reduction in blood glucose levels, have already been identified behind the beneficial effect of these drugs. However, there is still much to be understood regarding the exact pathomechanisms. This review provides an overview of the current literature and sheds light on the modes of action of novel antidiabetic drugs, focusing on inflammation, oxidative stress, and fibrosis.

Muscular Sestrins: Roles in Exercise Physiology and Stress Resistance

Sestrins are a family of stress-inducible proteins that are critical for stress adaptation and the maintenance of metabolic homeostasis. High expression of Sestrins is observed in skeletal and cardiac muscle tissues, suggesting their significance in the physiological homeostasis of these organs. Furthermore, expression of Sestrins is dynamically controlled in the tissues, based on the level of physical activity and the presence or absence of stress insults. Genetic studies in model organisms have shown that muscular Sestrin expression is critical for metabolic homeostasis, exercise adaptation, stress resistance, and repair and may mediate the beneficial effects of some available therapeutics. The current minireview summarizes and discusses recent findings that shed light on the role of Sestrins in regulating muscle physiology and homeostasis.

Insights into SGLT2 inhibitor treatment of diabetic cardiomyopathy: focus on the mechanisms

Among the complications of diabetes, cardiovascular events and cardiac insufficiency are considered two of the most important causes of death. Experimental and clinical evidence supports the effectiveness of SGLT2i for improving cardiac dysfunction. SGLT2i treatment benefits metabolism, microcirculation, mitochondrial function, fibrosis, oxidative stress, endoplasmic reticulum stress, programmed cell death, autophagy, and the intestinal flora, which are involved in diabetic cardiomyopathy. This review summarizes the current knowledge of the mechanisms of SGLT2i for the treatment of diabetic cardiomyopathy.

Effect and mechanism of Magnolia officinalis pharmacopuncture for treating localized fat via network pharmacology and experimental study

Background

Recently, for various reasons, the need for non-invasive treatment for localized fat has emerged. This study confirmed whether Magnolia officinalis (MO) pharmacopuncture reduces localized fat by promoting lipolysis and inhibiting adipogenesis.

Methods

The network was built using genes related to the active compound of MO and the mode of action of MO was predicted by the functional enrichment analysis. Based on the result from network analysis, 100 µL of 2 mg/mL MO pharmacopuncture was injected into the inguinal fat pad for 6 weeks in obese C57BL/6J mice. Normal saline was injected into the right-side inguinal fat pad as a self-control.

Results

It was expected that the 'AMP-activated protein kinase (AMPK) signaling pathway' would be affected by the MO Network. MO pharmacopuncture reduced the weight and size of inguinal fat in HFD-induced obese mice. The phosphorylation of AMPK along with the increases of lipases was significantly increased by MO injection. Also, the expression levels of fatty acid synthesize-related mediators were suppressed by MO injection.

Conclusion

Our results demonstrated that MO pharmacopuncture promoted the expression of AMPK, which has beneficial effects on activation of lipolysis and inhibition of lipogenesis. Pharmacopuncture of MO can be a non-surgical alternative therapy in the treatment of local fat tissue.

Quercetin activates the Sestrin2/AMPK/SIRT1 axis to improve amyotrophic lateral sclerosis

Amyotrophic lateral sclerosis (ALS) is a chronic neurodegenerative disease with poor prognosis. The intricacies surrounding its pathophysiology could partly account for the lack of effective treatment for ALS. Sestrin2 has been reported to improve metabolic, cardiovascular and neurodegenerative diseases, and is involved in the direct and indirect activation of the adenosine 5'-monophosphate (AMP)-activated protein kinase (AMPK)/silent information regulator 1 (SIRT1) axis. Quercetin, as a phytochemical, has considerable biological activities, such as anti-oxidation, anti-inflammation, anti-tumorigenicity, and neuroprotection. Interestingly, quercetin can activate the AMPK/SIRT1 signaling pathway to reduce endoplasmic reticulum stress, and alleviate apoptosis and inflammation. This report examines the molecular relationship between Sestrin2 and AMPK/SIRT1 axis, as well as the main biological functions and research progress of quercetin, together with the correlation between quercetin and Sestrin2/AMPK/SIRT1 axis in neurodegenerative diseases.

Celastrol confers ferroptosis resistance via AKT/GSK3β signaling in high-fat diet-induced cardiac injury

Obesity-induced cardiac dysfunction is a severe global disease associated with high dietary fat intake, and its pathogenesis includes inflammation, oxidative stress, and ferroptosis. Celastrol (Cel) is a bioactive compound isolated from the herb Tripterygium wilfordii, which has a protective influence on cardiovascular diseases. In this study, the role of Cel in obesity-induced ferroptosis and cardiac injury was investigated. We found that Cel alleviated ferroptosis induced by Palmitic acid (PA), exhibiting a decrease in the LDH, CK-MB, Ptgs2, and Lipid Peroxidation levels. After cardiomyocytes were treated with additional LY294002 and LiCl, Cel exerted its protective effect through increased AKT/GSK3β phosphorylation and decreased level of lipid peroxidation and Mitochondrial ROS. The systolic left ventricle (LV) dysfunction of obese mice was alleviated via ferroptosis inhibition by elevated p-GSK3β and decreased Mitochondrial ROS under Cel treatment. Moreover, mitochondrial anomalies included swelling and distortion in the myocardium which was relieved with Cel. In conclusion, our results demonstrate that ferroptosis resistance with Cel under HFD conditions targets AKT/GSK3β signaling, which provides novel therapeutic strategies in obesity-induced cardiac injury.

Empagliflozin ameliorates cardiac dysfunction in heart failure mice via regulating mitochondrial dynamics

Empagliflozin has cardioprotective effects in patients with heart failure (HF). However, the mechanism by which empagliflozin protects against HF remains controversial. Study aimed to evaluate the effect of empagliflozin on myocardial fibrosis and cardiac function in HF mice and its possible mechanism. C57BL/6 mice were induced with HF by ligation of the left anterior descending coronary artery. At 4 weeks postoperation, mice were randomly given normal saline or empagliflozin for 8 weeks. Echocardiography was used to assess cardiac function. Masson's staining, immunohistochemistry and Western blot analysis were used to detect the degree of myocardial fibrosis. Changes in mitochondria were detected by observing mitochondrial morphology, measuring mitochondrial dynamics-related proteins and analysing the levels of adenosine triphosphate (ATP), adenosine monophosphate (AMP) and adenosine diphosphate (ADP). The mitochondrial fission inhibitor, mdivi1, was used to detect the relationship between mitochondrial dysfunction and cardiac dysfunction in HF mice. HF led to myocardial fibrosis and cardiac dysfunction. However, treatment with empagliflozin reduced these effects. Empagliflozin inhibited mitochondrial fission and improved energy metabolic efficiency in HF mice by regulating the expression of mitochondrial dynamics-related proteins. Similarly, mdivi1 attenuated mitochondrial dysfunction and cardiac dysfunction by inhibiting mitochondrial fission in HF mice. Regulation of mitochondrial dynamics, especially inhibition of mitochondrial fission, may be a potential target for reducing cardiac damage in patients with HF. Empagliflozin improved myocardial fibrosis and cardiac dysfunction by modulating mitochondrial dynamics in HF mice. Thus, the cardiac protective effect of empagliflozin may be related to the normalization of mitochondria and the increase in ATP production.

Sestrin2 as a Protective Shield against Cardiovascular Disease

A timely and adequate response to stress is inherently present in each cell and is important for maintaining the proper functioning of the cell in changing intracellular and extracellular environments. Disruptions in the functioning or coordination of defense mechanisms against cellular stress can reduce the tolerance of cells to stress and lead to the development of various pathologies. Aging also reduces the effectiveness of these defense mechanisms and results in the accumulation of cellular lesions leading to senescence or death of the cells. Endothelial cells and cardiomyocytes are particularly exposed to changing environments. Pathologies related to metabolism and dynamics of caloric intake, hemodynamics, and oxygenation, such as diabetes, hypertension, and atherosclerosis, can overwhelm endothelial cells and cardiomyocytes with cellular stress to produce cardiovascular disease. The ability to cope with stress depends on the expression of endogenous stress-inducible molecules. Sestrin2 (SESN2) is an evolutionary conserved stress-inducible cytoprotective protein whose expression is increased in response to and defend against different types of cellular stress. SESN2 fights back the stress by increasing the supply of antioxidants, temporarily holding the stressful anabolic reactions, and increasing autophagy while maintaining the growth factor and insulin signaling. If the stress and the damage are beyond repair, SESN2 can serve as a safety valve to signal apoptosis. The expression of SESN2 decreases with age and its levels are associated with cardiovascular disease and many age-related pathologies. Maintaining sufficient levels or activity of SESN2 can in principle prevent the cardiovascular system from aging and disease.

The protective effects of SGLT-2 inhibitors, GLP-1 receptor agonists, and RAAS blockers against renal injury in patients with type 2 diabetes

Diabetic kidney disease is one of the most severe complications of type 2 diabetes mellitus. Patients with diabetic kidney disease have a worse prognosis in terms of mortality and morbidity, compared with patients who have diabetes alone. Strict control of blood pressure and blood glucose is the primary method for prevention of initial kidney damage and delaying further progression of existing damage. Other management approaches include the use of exogenous drugs that can effectively protect the kidneys from diabetes, such as sodium-glucose transporter 2 inhibitors, glucagon-like peptide-1 receptor agonists, and renin-angiotensin-aldosterone system blockers. These drugs may protect against kidney injury through various molecular mechanisms. This review focuses on renal impairment in patients with type 2 diabetes; it discusses the direct and indirect effects of sodium-glucose transporter 2 inhibitors, glucagon-like peptide-1 receptor agonists, and renin-angiotensin-aldosterone system blockers on diabetic kidney disease. Finally, it discusses the effects of combination treatment with two or three types of drugs in patients with chronic kidney disease.

Farnesoid X Receptor (FXR) Regulates mTORC1 Signaling and Autophagy by Inhibiting SESN2 Expression

SCOPE

The mechanistic target of rapamycin complex 1 (mTORC1), as a link between nutrients and autophagy, senses many nutrients in the microenvironment. A growing body of recent literature describes the function of bile acids (BAs) as versatile signaling molecules, while it remains largely unclear whether mTORC1 can sense BAs and the mechanism has not been studied.

METHODS AND RESULTS

After treating LO2 cells with indicated concentration of chenodeoxycholic acid (CDCA) and farnesoid X receptor (FXR) inhibitor/activator for 6 h, it finds that CDCA and FXR significantly accelerate mTORC1 activation. The results of immunofluorescence indicate that CDCA and FXR inhibit cellular autophagy through activating mTORC1 pathway. In particular, these findings show that CDCA and FXR promote the lysosomal translocation and activation of mTORC1 in an amino acid-sensitive manner. Mechanistically, the transcriptomics data indicate that SESN2 is a checkpoint for mTORC1 lysosome translocation and activation induced by FXR, and knockdown SESN2 with siRNA suppresses the regulation of FXR on autophagy.

CONCLUSION

These results indicate that FXR-induced decrease in SESN2 expression and activation of the mTORC1 pathway can control autophagy and be explored as potential therapeutic targets for enterohepatic and metabolic disorders.

Targeting high glucose-induced epigenetic modifications at cardiac level: the role of SGLT2 and SGLT2 inhibitors

BACKGROUND

Sodium-glucose co-transporters (SGLT) inhibitors (SGLT2i) showed many beneficial effects at the cardiovascular level. Several mechanisms of action have been identified. However, no data on their capability to act via epigenetic mechanisms were reported. Therefore, this study aimed to investigate the ability of SGLT2 inhibitors (SGLT2i) to induce protective effects at the cardiovascular level by acting on DNA methylation.

METHODS

To better clarify this issue, the effects of empagliflozin (EMPA) on hyperglycemia-induced epigenetic modifications were evaluated in human ventricular cardiac myoblasts AC16 exposed to hyperglycemia for 7 days. Therefore, the effects of EMPA on DNA methylation of NF-κB, SOD2, and IL-6 genes in AC16 exposed to high glucose were analyzed by pyrosequencing-based methylation analysis. Modifications of gene expression and DNA methylation of NF-κB and SOD2 were confirmed in response to a transient SGLT2 gene silencing in the same cellular model. Moreover, chromatin immunoprecipitation followed by quantitative PCR was performed to evaluate the occupancy of TET2 across the investigated regions of NF-κB and SOD2 promoters.

RESULTS

Seven days of high glucose treatment induced significant demethylation in the promoter regions of NF-kB and SOD2 with a consequent high level in mRNA expression of both genes. The observed DNA demethylation was mediated by increased TET2 expression and binding to the CpGs island in the promoter regions of analyzed genes. Indeed, EMPA prevented the HG-induced demethylation changes by reducing TET2 binding to the investigated promoter region and counteracted the altered gene expression. The transient SGLT2 gene silencing prevented the DNA demethylation observed in promoter regions, thus suggesting a role of SGLT2 as a potential target of the anti-inflammatory and antioxidant effect of EMPA in cardiomyocytes.

CONCLUSIONS

In conclusion, our results demonstrated that EMPA, mainly acting on SGLT2, prevented DNA methylation changes induced by high glucose and provided evidence of a new mechanism by which SGLT2i can exert cardio-beneficial effects.

Sodium-glucose Cotransporter 2 Inhibitors and Pathological Myocardial Hypertrophy

Sodium-glucose cotransporter 2 (SGLT2) inhibitors are a new type of oral hypoglycemic drugs that exert a hypoglycemic effect by blocking the reabsorption of glucose in the proximal renal tubules, thus promoting the excretion of glucose from urine. Their hypoglycemic effect is not dependent on insulin. Increasing data shows that SGLT2 inhibitors improve cardiovascular outcomes in patients with type 2 diabetes. Previous studies have demonstrated that SGLT2 inhibitors can reduce pathological myocardial hypertrophy with or without diabetes, but the exact mechanism remains to be elucidated. To clarify the relationship between SGLT2 inhibitors and pathological myocardial hypertrophy, with a view to providing a reference for the future treatment thereof, this study reviewed the possible mechanisms of SGLT2 inhibitors in attenuating pathological myocardial hypertrophy. We focused specifically on the mechanisms in terms of inflammation, oxidative stress, myocardial fibrosis, mitochondrial function, epicardial lipids, endothelial function, insulin resistance, cardiac hydrogen and sodium exchange, and autophagy.