MicroRNAs in diabetic macroangiopathy

Pathological Glucose Levels Enhance Entry Factor Expression and Hepatic SARS-CoV-2 Infection

Accumulating clinical evidence suggests an intricate relationship between severe COVID-19 and preexisting metabolic complications, which share some metabolic dysregulations, including hyperglycaemia, hyperinsulinaemia and hyperlipidaemia. However, the potential role of these metabolic risk factors in SARS-CoV-2 infection and entry factor expression remains unknown. Here we report the implication of hyperglycaemia in SARS-CoV-2 infection and therapy. Hyperglycaemia, instead of hyperinsulinaemia and hyperlipidaemia, can significantly induce the expression of SARS-CoV-2 entry factors (Ace2, Tmprss2, Tmprss4, Furin and Nrp1) in liver cells, but not in lung and pancreatic cells, which is attenuated by mTOR inhibition. Correspondingly, pathological glucose levels promote SARS-CoV-2 entry into cultured hepatocytes in pseudovirus cell systems. Conversely, representative glucose-lowering drugs (metformin, dapagliflozin, sitagliptin and exenatide) are able to diminish the enhancement of entry factor expression and SARS-CoV-2 infection in cultured hepatocytes under pathological glucose conditions. Intriguingly, SARS-CoV-2 entry factors are increased in the livers of nonalcoholic fatty liver disease and diabetes patients. These results define hyperglycaemia as a key susceptibility factor for hepatic SARS-CoV-2 infection, and provide insights into the clinical application of glucose-lowering therapies in COVID-19 patients under comorbid hyperglycaemia conditions.

Regulation of vascular smooth muscle cells phenotype by metformin up-regulated miR-1/ CCND1 axis via targeting AMPK/TGF-β signaling pathway

The phenotypic switch of vascular smooth muscle cells (VSMCs), characterized by the tissue-specific expression of certain microRNAs (miRNAs), is a critical factor in the development of diabetic vascular diseases. Metformin, a widely prescribed anti-diabetic medication for type 2 diabetes treatment, activates the adenosine monophosphate-activated protein kinase (AMPK) pathway and exerts a protective effect on vascular endothelium. Although the regulatory effects of metformin on the switch of the vascular smooth muscle cell phenotype have been identified, the specific role of miRNAs in this process remains unclear. We identified a specific miR-1 in response to metformin treatment and determined its effects on both miR-1 and its targets. Subsequently, we investigated the influence of these factors on the metformin-induced phenotype switch in vascular smooth muscle cells, specifically focusing on proliferation and migration, as well as activation of the AMPK/Transforming Growth Factor (TGF-β) axis. This was achieved using various methodologies, including bioinformatics analysis, quantitative real-time polymerase chain reaction (qRT-PCR), Western blot analysis, wound scratch assays, and Cell Counting Kit-8 assays. Our findings showed that metformin upregulated miR-1, which directly targets cyclin D1 (CCND1) in VSMCs. Metformin was observed to enhance the expression of contractile phenotype proteins, including α-smooth muscle actin (α-SMA) and smooth muscle myosin heavy chain (SMMHC), while simultaneously reducing the expression of proliferative phenotype proteins such as CCND1 and proliferating cell nuclear antigen (PCNA). The inhibition of miR-1 was found to reverse the effects of metformin on the phenotypic switch of VSMCs. This occurs partly through the AMPK/TGF-β signaling pathway and inhibits the migration and proliferation of VSMCs.

Exercise and dietary interventions in the management of diabetic cardiomyopathy: mechanisms and implications

The global prevalence of diabetes is rapidly increasing, significantly raising the risk of various cardiovascular diseases. Among these, diabetic cardiomyopathy (DCM) is a distinct and critical complication characterized by ventricular hypertrophy and impaired myocardial contractility, ultimately progressing to heart failure and making it a leading cause of mortality among diabetic patients. Despite advances in pharmacological therapies, the effectiveness of managing cardiac dysfunction in DCM remains challenging. Consequently, exploring additional therapeutic strategies for the prevention and treatment of DCM is urgently needed. Beyond pharmacological approaches, lifestyle modifications, particularly exercise and dietary interventions, play a fundamental role in managing DCM due to their significant cardiovascular benefits in diabetic patients. This review synthesizes recent advancements in the field, elucidating the underlying mechanisms through which exercise and dietary interventions influence DCM pathophysiology. By integrating these strategies, we aim to facilitate the development of personalized exercise and dietary regimens that effectively mitigate or prevent DCM progression.

Metabolic and Mitochondrial Dysregulations in Diabetic Cardiac Complications

The growing prevalence of diabetes highlights the urgent need to study diabetic cardiovascular complications, specifically diabetic cardiomyopathy, which is a diabetes-induced myocardial dysfunction independent of hypertension or coronary artery disease. This review examines the role of mitochondrial dysfunction in promoting diabetic cardiac dysfunction and highlights metabolic mechanisms such as hyperglycaemia-induced oxidative stress. Chronic hyperglycaemia and insulin resistance can activate harmful pathways, including advanced glycation end-products (AGEs), protein kinase C (PKC) and hexosamine signalling, uncontrolled reactive oxygen species (ROS) production and mishandling of Ca2+ transient. These processes lead to cardiomyocyte apoptosis, fibrosis and contractile dysfunction. Moreover, endoplasmic reticulum (ER) stress and dysregulated RNA-binding proteins (RBPs) and extracellular vesicles (EVs) contribute to tissue damage, which drives cardiac function towards heart failure (HF). Advanced patient-derived induced pluripotent stem cell (iPSC) cardiac organoids (iPS-COs) are transformative tools for modelling diabetic cardiomyopathy and capturing human disease's genetic, epigenetic and metabolic hallmarks. iPS-COs may facilitate the precise examination of molecular pathways and therapeutic interventions. Future research directions encourage the integration of advanced models with mechanistic techniques to promote novel therapeutic strategies.

Long Non-Coding RNAs in Diabetic Cardiomyopathy: Potential Function as Biomarkers and Therapeutic Targets of Exercise Training

Recent studies emphasize the beneficial effects of exercise on diabetic cardiomyopathy (DCM), adding to the growing body of evidence that underscores the role of exercise in improving health outcomes. Despite this, a notable gap persists in the number of healthcare providers who actively prescribe exercise as a therapeutic intervention for DCM management. In addition, exercise modulates the expression of lncRNAs, which play a pivotal role in DCM progression. Further investigation into this relationship may facilitate the identification of novel biomarkers and therapeutic targets for DCM. This review consolidates recent advances in identifying lncRNAs biomarkers in DCM, summarizing the current knowledge on dysregulated lncRNAs and their molecular mechanisms. Additionally, it offers new insights into the mechanistic roles of lncRNAs, highlighting their potential as biomarkers and therapeutic targets for DCM. Overall, this review aims to inform future research and reinforce the significance of addressing diabetes-related cardiovascular diseases to potentially improve clinical outcomes.