Cardiovascular microRNAs: as modulators and diagnostic biomarkers of diabetic heart disease

Circular RNAs: a small piece in the heart failure puzzle

Cardiovascular disease, specifically heart failure (HF), remains a significant concern in the realm of healthcare, necessitating the development of new treatments and biomarkers. The RNA family consists of various subgroups, including microRNAs, PIWI-interacting RNAs (piRAN) and long non-coding RNAs, which have shown potential in advancing personalized healthcare for HF patients. Recent research suggests that circular RNAs, a lesser-known subgroup of RNAs, may offer a novel set of targets and biomarkers for HF. This review will discuss the biogenesis of circular RNAs, their unique characteristics relevant to HF, their role in heart function, and their potential use as biomarkers in the bloodstream. Furthermore, future research directions in this field will be outlined. The stability of exosomal circRNAs makes them suitable as biomarkers, pathogenic regulators, and potential treatments for cardiovascular diseases such as atherosclerosis, acute coronary syndrome, ischemia/reperfusion injury, HF, and peripheral artery disease. Herein, we summarized the role of circular RNAs and their exosomal forms in HF diseases.

The Effect of Glycemic Status on P Wave Dispersion

Background and aim The growing number of people with diabetes mellitus (DM) across the world is a public health concern. The diabetes epidemic involves enormous health costs to the patients, their careers, and society at large. Cardiovascular diseases such as atrial fibrillation (AF) often develop in the diabetic population. An increase in the P wave dispersion (PWD) has been established as an independent risk factor for the occurrence of AF, hence the present study was conducted to establish a possible relationship between PWD and the glycemic status of the individual to predict the occurrence of AF ahead of clinical symptomology. Methodology A comparative cross-sectional study was conducted at a tertiary care hospital after obtaining approval from the institutional ethics committee and written consent of each study subject. The main steps included the selection and categorization of the study population based on their glycemic status, collection of demographic data, performing ECGs calculating PWD using digital calipers, and recording the data systematically for evaluation. Results In this study, 234 patients with a mean age of 53.3 ± 13.1 years were studied, of which 121 (51.7%) were male and 113 (48.29%) were female. The 234 patients were divided into four groups based on their glycemic status - 74 uncontrolled DM patients (31.62%), 51 type 2 DM (T2DM) patients (21.78%), 56 prediabetes patients (23.93%), and 53 patients in the control group (22.64%; not a known case of diabetes with normal HbA1c and fasting blood sugar (FBS) levels). Minimal correlation was observed between FBS with PWD (r value 0.175) and age with PWD (r value 0.161), but statistical significance was observed only between age and PWD (p-value 0.014). The difference in means between the four different study groups was found to be not statistically significant (p-value- 0.104); hence, no intergroup variation was noted. Conclusion Advancing age and higher fasting blood sugars have shown minimal correlation with widening P-wave dispersion. With further studies involving larger populations, this can be a promising aid in identifying PWD as a probable early predictor of atrial arrhythmias among diabetic patients.

Step-by-step fabrication of heart-on-chip systems as models for cardiac disease modeling and drug screening

Cardiovascular diseases are caused by hereditary factors, environmental conditions, and medication-related issues. On the other hand, the cardiotoxicity of drugs should be thoroughly examined before entering the market. In this regard, heart-on-chip (HOC) systems have been developed as a more efficient and cost-effective solution than traditional methods, such as 2D cell culture and animal models. HOCs must replicate the biology, physiology, and pathology of human heart tissue to be considered a reliable platform for heart disease modeling and drug testing. Therefore, many efforts have been made to find the best methods to fabricate different parts of HOCs and to improve the bio-mimicry of the systems in the last decade. Beating HOCs with different platforms have been developed and techniques, such as fabricating pumpless HOCs, have been used to make HOCs more user-friendly systems. Recent HOC platforms have the ability to simultaneously induce and record electrophysiological stimuli. Additionally, systems including both heart and cancer tissue have been developed to investigate tissue-tissue interactions' effect on cardiac tissue response to cancer drugs. In this review, all steps needed to be considered to fabricate a HOC were introduced, including the choice of cellular resources, biomaterials, fabrication techniques, biomarkers, and corresponding biosensors. Moreover, the current HOCs used for modeling cardiac diseases and testing the drugs are discussed. We finally introduced some suggestions for fabricating relatively more user-friendly HOCs and facilitating the commercialization process.

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.

Molecular Processes Involved in the Shared Pathways between Cardiovascular Diseases and Diabetes

Cardiovascular diseases and diabetes mellitus are currently among the diseases with the highest morbidity and mortality. The pathogenesis and development of these diseases remain strongly connected, along with inflammation playing a major role. Therefore, the treatment possibilities showing a positive impact on both of these diseases could be especially beneficial for patients. SGLT-2 inhibitors and GLP-1 receptor agonists present this dual effect. Moreover, the hostile composition of the gut microbiota could influence the progression of these conditions. In this review, the authors present the latest knowledge on and innovations in diabetes mellitus and CVD-with the focus on the molecular mechanisms and the role of the microbiota.

Exploring the Complex Relationship between Diabetes and Cardiovascular Complications: Understanding Diabetic Cardiomyopathy and Promising Therapies

Diabetes mellitus (DM) and cardiovascular complications are two unmet medical emergencies that can occur together. The rising incidence of heart failure in diabetic populations, in addition to apparent coronary heart disease, ischemia, and hypertension-related complications, has created a more challenging situation. Diabetes, as a predominant cardio-renal metabolic syndrome, is related to severe vascular risk factors, and it underlies various complex pathophysiological pathways at the metabolic and molecular level that progress and converge toward the development of diabetic cardiomyopathy (DCM). DCM involves several downstream cascades that cause structural and functional alterations of the diabetic heart, such as diastolic dysfunction progressing into systolic dysfunction, cardiomyocyte hypertrophy, myocardial fibrosis, and subsequent heart failure over time. The effects of glucagon-like peptide-1 (GLP-1) analogues and sodium-glucose cotransporter-2 (SGLT-2) inhibitors on cardiovascular (CV) outcomes in diabetes have shown promising results, including improved contractile bioenergetics and significant cardiovascular benefits. The purpose of this article is to highlight the various pathophysiological, metabolic, and molecular pathways that contribute to the development of DCM and its significant effects on cardiac morphology and functioning. Additionally, this article will discuss the potential therapies that may be available in the future.

Exosomal non coding RNAs as a novel target for diabetes mellitus and its complications

Diabetes mellitus (DM) is a first-line priority among the problems facing medical science and public health in almost all countries of the world. The main problem of DM is the high incidence of damage to the cardiovascular system, which in turn leads to diseases such as myocardial infarction, stroke, gangrene of the lower extremities, blindness and chronic renal failure. As a result, the study of the molecular genetic mechanisms of the pathogenesis of DM is of critical importance for the development of new diagnostic and therapeutic strategies. Molecular genetic aspects of the etiology and pathogenesis of diabetes mellitus are intensively studied in well-known laboratories around the world. One of the strategies in this direction is to study the role of exosomes in the pathogenesis of DM. Exosomes are microscopic extracellular vesicles with a diameter of 30-100 nm, released into the intercellular space by cells of various tissues and organs. The content of exosomes depends on the cell type and includes mRNA, non-coding RNAs, DNA, and so on. Non-coding RNAs, a group of RNAs with limited transcriptional activity, have been discovered to play a significant role in regulating gene expression through epigenetic and posttranscriptional modulation, such as silencing of messenger RNA. One of the problems of usage exosomes in DM is the identification of the cellular origin of exosomes and the standardization of protocols for molecular genetic studies in clinical laboratories. In addition, the question of the target orientation of exosomes and their targeted activity requires additional study. Solving these and other problems will make it possible to use exosomes for the diagnosis and delivery of drugs directly to target cells in DM. This study presents an analysis of literature data on the role of exosomes and ncRNAs in the development and progression of DM, as well as the prospects for the use of exosomes in clinical practice in this disease.

Regulation of HIF-1 by MicroRNAs in Various Cardiovascular Diseases

Today, we see an increase in death due to cardiovascular diseases all over the world, which has a lot to do with the regulation of oxygen homeostasis. Also, hypoxia-inducing factor 1 (HIF-1) is considered a vital factor in hypoxia and its physiological and pathological changes. HIF- 1 is involved in cellular activities, including proliferation, differentiation, and cell death in endothelial cells (ECs) and cardiomyocytes. Similar to HIF-1α, which acts as a protective element against various diseases in the cardiovascular system, the protective role of microRNAs (miRNAs) has also been proved using animal models. The number of miRNAs identified in the regulation of gene expression responsive to hypoxia and the importance of investigating the involvement of the non-coding genome in cardiovascular diseases is increasing, which shows the issue's importance. In this study, the molecular regulation of HIF-1 by miRNAs is considered to improve therapeutic approaches in clinical diagnoses of cardiovascular diseases.

Profile of crosstalk between glucose and lipid metabolic disturbance and diabetic cardiomyopathy: Inflammation and oxidative stress

In recent years, the risk, such as hypertension, obesity and diabetes mellitus, of cardiovascular diseases has been increasing explosively with the development of living conditions and the expansion of social psychological pressure. The disturbance of glucose and lipid metabolism contributes to both collapse of myocardial structure and cardiac dysfunction, which ultimately leads to diabetic cardiomyopathy. The pathogenesis of diabetic cardiomyopathy is multifactorial, including inflammatory cascade activation, oxidative/nitrative stress, and the following impaired Ca2+ handling induced by insulin resistance/hyperinsulinemia, hyperglycemia, hyperlipidemia in diabetes. Some key alterations of cellular signaling network, such as translocation of CD36 to sarcolemma, activation of NLRP3 inflammasome, up-regulation of AGE/RAGE system, and disequilibrium of micro-RNA, mediate diabetic oxidative stress/inflammation related myocardial remodeling and ventricular dysfunction in the context of glucose and lipid metabolic disturbance. Here, we summarized the detailed oxidative stress/inflammation network by which the abnormality of glucose and lipid metabolism facilitates diabetic cardiomyopathy.

Research progress on the relationship between autophagy and chronic complications of diabetes

Diabetes is a common metabolic disease whose hyperglycemic state can induce diverse complications and even threaten human health and life security. Currently, the treatment of diabetes is restricted to drugs that regulate blood glucose and have certain accompanying side effects. Autophagy, a research hotspot, has been proven to be involved in the occurrence and progression of the chronic complications of diabetes. Autophagy, as an essential organismal defense mechanism, refers to the wrapping of cytoplasmic proteins, broken organelles or pathogens by vesicles, which are then degraded by lysosomes to maintain the stability of the intracellular environment. Here, we review the relevant aspects of autophagy and the molecular mechanisms of autophagy in diabetic chronic complications, and further analyze the impact of improving autophagy on diabetic chronic complications, which will contribute to a new direction for further prevention and treatment of diabetic chronic complications.

MicroRNAs as biomarkers for monitoring cardiovascular changes in Type II Diabetes Mellitus (T2DM) and exercise

Introduction

MicroRNAs (miRNAs) have been shown to be altered in both CVD and T2DM and can have an application as diagnostic and prognostic biomarkers. miRNAs are released into circulation when the cardiomyocyte is subjected to injury and damage.

Objectives

Measuring circulating miRNA levels in human plasma may be of great potential use for measuring the extent of damage to cardiomyocytes and response to exercise. This review is aimed to highlight the potential application of miRNAs as biomarkers of CVD progression in T2DM, and the impact of exercise on recovery.

Methods

The review aims to examine whether the health improvements following exercise in T2DM patients are reflective of changes in expression of plasma miRNAs. For this purpose, studies were identified from the literature that have established a correlation between diabetes, disease progression and plasma miRNA levels. We also reviewed studies which looked at the effect of exercise on plasma miRNA levels.

Results

The review identified miRNA signatures that are affected by T2DM and DHD and a subset of these miRNAs that are also affected by different types of exercise. This approach helped us to identify those miRNAs whose expression and function can be altered by regular bouts of exercise.

Conclusions

miRNAs identified as part of this review can serve as tools to monitor the cardio-protective, anti-inflammatory and metabolic effects of exercise in people suffering from T2DM. Future research should focus on regulation of these miRNAs in T2DM and how they can be altered by appropriate exercise interventions.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40200-022-01066-4.

Combined use of systemic quercetin, glutamine and alpha-tocopherol attenuates myocardial fibrosis in diabetic rats

This study aimed to analyze the effects of the quercetin (100 mg/kg), 1% glutamine and 1% α-tocopherol antioxidants in the myocardium of rats with streptozotocin-induced diabetes mellitus. Twenty male rats were subdivided into four groups (n = 5): N (normoglycemic); D (diabetic); NT (normoglycemic treated with antioxidants); and DT (diabetic treated with antioxidants) treated for 60 days. Clinical parameters, oxidative stress markers, inflammatory cytokines, myocardial collagen fibers and immunoexpression of superoxide dismutase 1 (SOD-1), glutathione peroxidase-1 (GPx-1), interleukin-1β (IL-1-β), transforming growth factor-beta (TGF-β), and fibroblast growth factor-2 (FGF-2) were evaluated. Results showed reduced body weight, hyperphagia, polydipsia and hyperglycemic state in groups D and DT. The levels of glutathione (GSH) were higher in NT and DT compared to N (p < 0.01) and D (p < 0.001) groups, respectively. Greater GSH levels were found in DT when compared to N animals (p < 0.001). In DT, there was an increase in IL-10 in relation to N, D and NT (p < 0.05), while GPx-1 expression was similar to N and lower compared to D (p < 0.001). TGF-β expression in DT was greater than N (p < 0.001) group, whereas FGF-2 in DT was higher than in the other groups (p < 0.001). A significant reduction in collagen fibers (type I) was found in DT compared to D (p < 0.05). The associated administration of quercetin, glutamine and α-tocopherol increased the levels of circulating interleukin-10 (IL-10) and GSH, and reduced the number of type I collagen fibers. Combined use of systemic quercetin, glutamine and alpha-tocopherol attenuates myocardial fibrosis in diabetic rats.

Exosomal microRNAs in diabetic heart disease

Diabetes is a metabolic disorder that affects millions of people worldwide. Diabetic heart disease (DHD) comprises coronary artery disease, heart failure, cardiac autonomic neuropathy, peripheral arterial disease, and diabetic cardiomyopathy. The onset and progression of DHD have been attributed to molecular alterations in response to hyperglycemia in diabetes. In this context, microRNAs (miRNAs) have been demonstrated to have a significant role in the development and progression of DHD. In addition to their effects on the host cells, miRNAs can be released into circulation after encapsulation within the exosomes. Exosomes are extracellular nanovesicles ranging from 30 to 180 nm in diameter secreted by all cell types. They carry diverse cargos that are altered in response to various conditions in their parent cells. Exosomal miRNAs have been extensively studied in recent years due to their role and therapeutic potential in DHD. This review will first provide an overview of exosomes, their biogenesis and function, followed by the role of exosomes in cardiovascular disease and then focuses on the known role of exosomes and associated miRNAs in DHD.

Circulating microRNAs as predictive biomarkers of coronary artery diseases in type 2 diabetes patients

BACKGROUND

Type 2 diabetes mellitus (T2DM) is an increasing metabolic disorder mostly resulting from unhealthy lifestyles. T2DM patients are prone to develop heart conditions such as coronary artery disease (CAD) which is a major cause of death in the world. Most clinical symptoms emerge at the advanced stages of CAD; therefore, establishing new biomarkers detectable in the early stages of the disease is crucial to enhance the efficiency of treatment. Recently, a significant body of evidence has shown alteration in miRNA levels associate with dysregulated gene expression occurring in T2DM and CAD, highlighting significance of circulating miRNAs in early detection of CAD arising from T2DM. Therefore, it seems crucial to establish a link between the miRNAs prognosing value and development of CAD in T2DM.

AIM

This study provides an overview on the alterations of the circulatory miRNAs in T2DM and various CADs and consider the potentials of miRNAs as biomarkers prognosing CADs in T2DM patients.

MATERIALS AND METHODS

Literature search was conducted for miRNAs involved in development of T2DM and CAD using the following key words: "miRNAs", "Biomarker", "Diabetes Mellitus Type 2 (T2DM)", "coronary artery diseases (CAD)". Articles written in the English language.

RESULT

There has been shown a rise in miR-375, miR-9, miR-30a-5p, miR-150, miR-9, miR-29a, miR-30d, miR-34a, miR-124a, miR-146a, miR-27a, and miR-320a in T2DM; whereas, miR-126, miR-21, miR-103, miR-28-3p, miR-15a, miR-145, miR-375, miR-223 have been shown to decrease. In addition to T2DM, some miRNAs such as mirR-1, miR-122, miR-132, and miR-133 play a part in development of subclinical aortic atherosclerosis associated with metabolic syndrome. Some miRNAs increase in both T2DM and CAD such as miR-1, miR-132, miR-133, and miR-373-3-p. More interestingly, some of these miRNAs such as miR-92a elevate years before emerging CAD in T2DM.

CONCLUSION

dysregulation of miRNAs plays outstanding roles in development of T2DM and CAD. Also, elevation of some miRNAs such as miR-92a in T2DM patients can efficiently prognose development of CAD in these patients, so these miRNAs can be used as biomarkers in this regard.

Serum miRNA Profile in Diabetic Patients With Ischemic Heart Disease as a Promising Non-Invasive Biomarker

The increasing morbidity and mortality of type 2 diabetic mellitus (T2DM) patients with ischemic heart disease (IHD) highlight an urgent need to identify early biomarkers, which would help to predict individual risk of development of IHD. Here, we postulate that circulating serum-derived micro RNAs (miRNAs) may serve as potential biomarkers for early IHD diagnosis and support the identification of diabetic individuals with a predisposition to undergo IHD. We obtained serum samples from T2DM patients either with IHD or IHD-free and analysed the expression levels of 798 miRNAs using the NanoString nCounter technology platform. The prediction of the putative miRNAs targets was performed using the Ingenuity Pathway Analysis (IPA) software. Gene Ontology (GO) analysis was used to identify the biological function and signalling pathways associated with miRNA target genes. Hub genes of protein-protein interaction (PPI) network were identified by STRING database and Cytotoscape tool. Receiver operating characteristic (ROC) analysis was used to assess the diagnostic value of identified miRNAs. Real-time quantitative polymerase chain reaction (qRT-PCR) was used for nCounter platform data validation. Our data showed that six miRNAs (miR-615-3p, miR-3147, miR-1224-5p, miR-5196-3p, miR-6732-3p, and miR-548b-3p) were significantly upregulated in T2DM IHD patients compared to T2DM patients without IHD. Further analysis indicated that 489 putative target genes mainly affected the endothelin-1 signalling pathway, glucocorticoid biosynthesis, and apelin cardiomyocyte signalling pathway. All tested miRNAs showed high diagnostic value (AUC = 0.779 - 0.877). Taken together, our research suggests that circulating miRNAs might have a crucial role in the development of IHD in diabetic patients and may be used as a potential biomarker for early diagnosis.

Non-coding RNAs in diabetes mellitus and diabetic cardiovascular disease

More than 10% of the world's population already suffers from varying degrees of diabetes mellitus (DM), but there is still no cure for the disease. Cardiovascular disease (CVD) is one of the most common and dangerous of the many health complications that can be brought on by DM, and has become the leading cause of death in people with diabetes. While research on DM and associated CVD is advancing, the specific mechanisms of their development are still unclear. Given the threat of DM and CVD to humans, the search for new predictive markers and therapeutic ideas is imminent. Non-coding RNAs (ncRNAs) have been a popular subject of research in recent years. Although they do not encode proteins, they play an important role in living organisms, and they can cause disease when their expression is abnormal. Numerous studies have observed aberrant ncRNAs in patients with DM complications, suggesting that they may play an important role in the development of DM and CVD and could potentially act as biomarkers for diagnosis. There is additional evidence that treatment with existing drugs for DM, such as metformin, alters ncRNA expression levels, suggesting that regulation of ncRNA expression may be a key mechanism in future DM treatment. In this review, we assess the role of ncRNAs in the development of DM and CVD, as well as the evidence for ncRNAs as potential therapeutic targets, and make use of bioinformatics to analyze differential ncRNAs with potential functions in DM.

MicroRNA-17-3p suppresses NF-κB-mediated endothelial inflammation by targeting NIK and IKKβ binding protein

Nuclear factor kappa B (NF-κB) activation contributes to many vascular inflammatory diseases. The present study tested the hypothesis that microRNA-17-3p (miR-17-3p) suppresses the pro-inflammatory responses via NF-κB signaling in vascular endothelium. Human umbilical vein endothelial cells (HUVECs), transfected with or without miR-17-3p agomir/antagomir, were exposed to lipopolysaccharide (LPS), and the inflammatory responses were determined. The cellular target of miR-17-3p was examined with dual-luciferase reporter assay. Mice were treated with miR-17-3p agomir and the degree of LPS-induced inflammation was determined. In HUVECs, LPS caused upregulation of miR-17-3p. Overexpression of miR-17-3p in HUVECs inhibited NIK and IKKβ binding protein (NIBP) protein expression and suppressed LPS-induced phosphorylation of inhibitor of kappa Bα (IκBα) and NF-κB-p65. The reduced NF-κB activity was paralleled by decreased protein levels of NF-κB-target gene products including pro-inflammatory cytokine [interleukin 6], chemokines [interleukin 8 and monocyte chemoattractant protein-1] and adhesion molecules [vascular cell adhesion molecule-1, intercellular adhesion molecule-1 and E-selectin]. Immunostaining revealed that overexpression of miR-17-3p reduced monocyte adhesion to LPS-stimulated endothelial cells. Inhibition of miR-17-3p with antagomir has the opposite effect on LPS-induced inflammatory responses in HUVECs. The anti-inflammatory effect of miR-17-3p was mimicked by NIBP knockdown. In mice treated with LPS, miR-17-3p expression was significantly increased. Systemic administration of miR-17-3p for 3 days suppressed LPS-induced NF-κB activation and monocyte adhesion to endothelium in lung tissues of the mice. In conclusion, miR-17-3p inhibits LPS-induced NF-κB activation in HUVECs by targeting NIBP. The findings therefore suggest that miR-17-3p is a potential therapeutic target/agent in the management of vascular inflammatory diseases.

The effect of aerobic exercise on the expression of mir-126 and related target genes in the endothelial tissue of the cardiac muscle of diabetic rats

BACKGROUND

The aim of this study was to investigate the effect of 8 weeks of aerobic exercise on the expression of mir-126 and some angiogenesis factors in the endothelial tissue of the cardiac muscle of type 2 diabetic rats.

METHODS

Sixteen male Wistar rats were divided into two groups: diabetic control and diabetic training. Nicotinamide and streptozotocin injections were used to induce type 2 diabetes. After familiarization, the training group participated in an 8-week exercise protocol on a treadmill with an intensity of 25 m per minute, a slope of 5% and 30 min per session. RT-PCR was used to evaluate the expression of mir-126 and PI3K genes. Expression of raf1, VEGF, blood glucose and insulin was determined by ELISA and insulin resistance was assessed by HOMA-IR homeostasis model. Immunohistochemistry was used to measure the capillary density of the cardiac muscle. Data were analyzed by t-test for independent groups with a significance level of p < 0.05.

RESULTS

Diabetes reduces angiogenesis in cardiac tissue, which is associated with a significant reduction in the expression of mir-126, raf1, VEGF and PI3K; while aerobic exercise increased the expression of mir-126, raf1, PI3K, VEGF. Exercise also decreased blood glucose levels and insulin resistance.

CONCLUSION

It seems that aerobic exercise can prevent the destructive effects of diabetes by activating the angiogenic pathway of cardiac tissue. Therefore, regulatory processes through mir-126, which are influenced by aerobic exercise, can be a valuable strategy in developing new treatments for diabetes.

Upregulated miR-200c is associated with downregulation of the functional receptor for severe acute respiratory syndrome coronavirus 2 ACE2 in individuals with obesity

Obesity is a risk factor for coronavirus disease 2019 (COVID-19) infection, with studies demonstrating the prevalence of individuals with obesity admitted with COVID-19 ranging between 30 and 60%. We determined whether early changes in microRNAs (miRNAs) are associated with dysregulation of angiotensin-converting enzyme 2 (ACE2), the specific functional receptor for severe acute respiratory syndrome coronavirus 2. ACE2 is a membrane-bound enzyme that catalyzes the conversion of angiotensin II to angiotensin 1–7 the latter having cardioprotective and vasorelaxation effects. Quantitative real-time PCR analysis of plasma samples for circulating miRNAs showed upregulation of miR-200c and miR-let-7b in otherwise healthy individuals with obesity. This was associated with significant downregulation of ACE2, a direct target for both miRNAs, in individuals with obesity. Correlation analysis confirmed a significant negative correlation between ACE2 and both the miRNAs. Studies showed that despite being the functional receptor, inhibition/downregulation of ACE2 did not reduce the severity of COVID-19 infection. In contrast, increased angiotensin II following inhibition of ACE2 may increase the severity of the disease. Taken together, our novel results identify that upregulation of miR-200c may increase the susceptibility of individuals with obesity to COVID-19. Considering miRNA are the earliest molecular regulators, the level of circulating miR-200c could be a potential biomarker in the early identification of those at the risk of severe COVID-19.

The Diabetic Cardiomyopathy: The Contributing Pathophysiological Mechanisms

Individuals with diabetes mellitus (DM) disclose a higher incidence and a poorer prognosis of heart failure (HF) than non-diabetic people, even in the absence of other HF risk factors. The adverse impact of diabetes on HF likely reflects an underlying “diabetic cardiomyopathy” (DM–CMP), which may by exacerbated by left ventricular hypertrophy and coronary artery disease (CAD). The pathogenesis of DM-CMP has been a hot topic of research since its first description and is still under active investigation, as a complex interplay among multiple mechanisms may play a role at systemic, myocardial, and cellular/molecular levels. Among these, metabolic abnormalities such as lipotoxicity and glucotoxicity, mitochondrial damage and dysfunction, oxidative stress, abnormal calcium signaling, inflammation, epigenetic factors, and others. These disturbances predispose the diabetic heart to extracellular remodeling and hypertrophy, thus leading to left ventricular diastolic and systolic dysfunction. This Review aims to outline the major pathophysiological changes and the underlying mechanisms leading to myocardial remodeling and cardiac functional derangement in DM-CMP.

Upregulation of microRNA-532 enhances cardiomyocyte apoptosis in the diabetic heart

Type 2 diabetes has a strong association with the development of cardiovascular disease, which is grouped as diabetic heart disease (DHD). DHD is associated with the progressive loss of cardiovascular cells through the alteration of molecular signalling pathways associated with cell death. In this study, we sought to determine whether diabetes induces dysregulation of miR-532 and if this is associated with accentuated apoptosis. RT-PCR analysis showed a significant increase in miR-532 expression in the right atrial appendage tissue of type 2 diabetic patients undergoing coronary artery bypass graft surgery. This was associated with marked downregulation of its anti-apoptotic target protein apoptosis repressor with caspase recruitment domain (ARC) and increased TUNEL positive cardiomyocytes. Further analysis showed a positive correlation between apoptosis and miR-532 levels. Time-course experiments in a mouse model of type 2 diabetes showed that diabetes-induced activation of miR-532 occurs in the later stage of the disease. Importantly, the upregulation of miR-532 preceded the activation of pro-apoptotic caspase-3/7 activity. Finally, inhibition of miR-532 activity in high glucose cultured human cardiomyocytes prevented the downregulation of ARC and attenuated apoptotic cell death. Diabetes induced activation of miR-532 plays a critical role in accelerating cardiomyocytes apoptosis. Therefore, miR-532 may serve as a promising therapeutic agent to overcome the diabetes-induced loss of cardiomyocytes.

Diabetic heart disease: A clinical update

Diabetes mellitus (DM) significantly increases the risk of heart disease, and DM-related healthcare expenditure is predominantly for the management of cardiovascular complications. Diabetic heart disease is a conglomeration of coronary artery disease (CAD), cardiac autonomic neuropathy (CAN), and diabetic cardiomyopathy (DCM). The Framingham study clearly showed a 2 to 4-fold excess risk of CAD in patients with DM. Pathogenic mechanisms, clinical presentation, and management options for DM-associated CAD are somewhat different from CAD among nondiabetics. Higher prevalence at a lower age and more aggressive disease in DM-associated CAD make diabetic individuals more vulnerable to premature death. Although common among diabetic individuals, CAN and DCM are often under-recognised and undiagnosed cardiac complications. Structural and functional alterations in the myocardial innervation related to uncontrolled diabetes result in damage to cardiac autonomic nerves, causing CAN. Similarly, damage to the cardiomyocytes from complex pathophysiological processes of uncontrolled DM results in DCM, a form of cardiomyopathy diagnosed in the absence of other causes for structural heart disease. Though optimal management of DM from early stages of the disease can reduce the risk of diabetic heart disease, it is often impractical in the real world due to many reasons. Therefore, it is imperative for every clinician involved in diabetes care to have a good understanding of the pathophysiology, clinical picture, diagnostic methods, and management of diabetes-related cardiac illness, to reduce morbidity and mortality among patients. This clinical review is to empower the global scientific fraternity with up-to-date knowledge on diabetic heart disease.

miR-18a increases insulin sensitivity by inhibiting PTEN

The miR-17-92 cluster (miR-17, miR-18a, miR-19a, miR-20a, miR-19b-1 and miR-92a) contributes to the occurrence and development of various diseases by inhibiting multiple target genes. Here, we explored the effects of miR-18a on insulin sensitivity. Quantitative real-time PCR indicated that serum miR-18a levels were lower in type 2 diabetes mellitus patients than in healthy controls, suggesting that miR-18a may influence blood glucose levels. Global overexpression of miR-18a in transgenic mice increased their glucose tolerance and insulin sensitivity, while it reduced expression of the phosphatase and tensin homolog deleted on chromosome ten (PTEN) in their skeletal muscle and adipose tissue. Western blotting indicated that overexpressing miR-18a in 3T3-L1 and C2C12 cells enhanced insulin-stimulated AKT phosphorylation and suppressed PTEN expression, while inhibiting miR-18a had the opposite effects. These results suggest that miR-18a improves insulin sensitivity by downregulating PTEN. This makes miR-18a a potentially useful target for the treatment of diabetes mellitus in the future.

Liraglutide Increases Serum Levels of MicroRNA-27b, -130a and -210 in Patients with Type 2 Diabetes Mellitus: A Novel Epigenetic Effect

Liraglutide has shown favourable effects on several cardiometabolic risk factors, beyond glucose control. MicroRNAs (miRNAs) regulate gene expression, resulting in post-transcriptional modifications of cell response and function. Specific miRNAs, including miRNA-27b, miRNA-130a, and miRNA-210, play a role in cardiometabolic disease. We aimed to determine the effect of liraglutide on the serum levels of miRNA-27b, miRNA-130a and miRNA-210. Twenty-five subjects with type-2 diabetes mellitus (T2DM), naïve to incretin-based therapy, were treated with liraglutide (1.2 mg/day as an add-on to metformin) for 4 months. miRNAs were quantified using real-time polymerase chain reaction. After liraglutide treatment, we found significant reductions in fasting glucose (from 9.8 ± 5.3 to 6.7 ± 1.6 mmol/L, p = 0.0042), glycosylated haemoglobin (HbA1c) (from 8.1 ± 0.8 to 6.6 ± 1.0%, p = 0.0008), total cholesterol (from 5.0 ± 1.0 to 4.0 ± 0.7 mmol/L, p = 0.0011), triglycerides (from 1.9 ± 1.0 to 1.5 ± 0.8 mmol/L, p = 0.0104) and low-density lipoprotein cholesterol (from 2.9 ± 1.2 to 2.2 ± 0.6 mmol/L, p = 0.0125), while the serum levels of miRNA-27b, miRNA-130a and miRNA-210a were significantly increased (median (interquartile range, IQR) changes: 1.73 (7.12) (p = 0.0401), 1.91 (3.64) (p = 0.0401) and 2.09 (11.0) (p = 0.0486), respectively). Since the changes in miRNAs were independent of changes in all the metabolic parameters investigated, liraglutide seems to exert a direct epigenetic effect in T2DM patients, regulating microRNAs involved in the maintenance of endothelial cell homeostasis. These changes might be implicated in liraglutide’s benefits and may represent useful targets for cardiometabolic management.

Exercise Regulates MicroRNAs to Preserve Coronary and Cardiac Function in the Diabetic Heart

RATIONALE

Diabetic heart disease (DHD) is a debilitating manifestation of type 2 diabetes mellitus. Exercise has been proposed as a potential therapy for DHD, although the effectiveness of exercise in preventing or reversing the progression of DHD remains controversial. Cardiac function is critically dependent on the preservation of coronary vascular function.

OBJECTIVE

We aimed to elucidate the effectiveness and mechanisms by which exercise facilitates coronary and cardiac-protection during the onset and progression of DHD.

METHODS AND RESULTS

Diabetic db/db and nondiabetic mice, with or without underlying cardiac dysfunction (16 and 8 weeks old, respectively) were subjected to either moderate-intensity exercise or high-intensity exercise for 8 weeks. Subsequently, synchrotron microangiography, immunohistochemistry, Western blot, and real-time polymerase chain reaction were used to assess time-dependent changes in cardiac and coronary structure and function associated with diabetes mellitus and exercise and determine whether these changes reflect the observed changes in cardiac-enriched and vascular-enriched microRNAs (miRNAs). We show that, if exercise is initiated from 8 weeks of age, both moderate-intensity exercise and high-intensity exercise prevented the onset of coronary and cardiac dysfunction, apoptosis, fibrosis, microvascular rarefaction, and disruption of miRNA signaling, as seen in the nonexercised diabetic mice. Conversely, the cardiovascular benefits of moderate-intensity exercise were absent if the exercise was initiated after the diabetic mice had already established cardiac dysfunction (ie, from 16 weeks of age). The experimental silencing or upregulation of miRNA-126 activity suggests the mechanism underpinning the cardiovascular benefits of exercise were mediated, at least in part, through tissue-specific miRNAs.

CONCLUSIONS

Our findings provide the first experimental evidence for the critical importance of early exercise intervention in ameliorating the onset and progression of DHD. Our results also suggest that the beneficial effects of exercise are mediated through the normalization of cardiovascular-enriched miRNAs, which are dysregulated in DHD.

Radiation-induced myocardial fibrosis: Mechanisms underlying its pathogenesis and therapeutic strategies

Radiation-induced myocardial fibrosis (RIMF) is a potentially lethal clinical complication of chest radiotherapy (RT) and a final stage of radiation-induced heart disease (RIHD). RIMF is characterized by decreased ventricular elasticity and distensibility, which can result in decreased ejection fraction, heart failure and even sudden cardiac death. Together, these conditions impair the long-term health of post-RT survivors and limit the dose and intensity of RT required to effectively kill tumour cells. Although the exact mechanisms involving in RIMF are unclear, increasing evidence indicates that the occurrence of RIMF is related to various cells, regulatory molecules and cytokines. However, accurately diagnosing and identifying patients who may progress to RIMF has been challenging. Despite the urgent need for an effective treatment, there is currently no medical therapy for RIMF approved for routine clinical application. In this review, we investigated the underlying pathophysiology involved in the initiation and progression of RIMF before outlining potential preventative and therapeutic strategies to counter this toxicity.

Exercise training attenuates diabetes-induced cardiac injury through increasing miR-133a and improving pro-apoptosis/anti-apoptosis balance in ovariectomized rats

Objective(s):

The useful and effective role of exercise program to prevent cardiac tissue apoptosis and fibrosis in ovariectomized type 2 diabetic (T2DM) rats (OVR.D) is well known. The current study aimed to investigate the simultaneous effects of T2DM and swimming plan on the expression of some apoptotic, anti-apoptotic biomarkers and glycogen changes in the cardiac muscle tissue of ovariectomized (OVR) rats.

Materials and Methods:

Forty rats were randomly sorted into 4 equal categories; sham, OVR, OVR.D and diabetic ovariectomized with an 8 week of swimming plan (OVR.D.E). Lipid profile and miR-133, Bcl-2, Bax, caspase-3 and caspase-8 levels were evaluated in the cardiac tissue.

Results:

Ovariectomy significantly (P-value<0.05) increased cholesterol, triglyceride, LDL, Bax, caspase-3, caspase-8 and decreased (P-value<0.05) HDL, miR-133, Bcl-2 in the cardiac tissue and a further reduction in the expression of miR-133, Bcl-2 and an enhancement in Bax, caspase-3 and caspase-8 in OVR.D rats was observed (P-value<0.01). However, exercise training significantly reversed all the measured parameters (P-value<0.05). Also, exercise training improved abnormal tissue structure, fragmentation and irregular form of glycogen granules in the OVR.D.E compared to OVR and OVR.D animals.

Conclusion:

Exercise training could prevent the cardiac disturbance, enhance the expression of anti-apoptotic markers and decrease apoptotic biomarkers in the hearts of OVR.D animals. Therefore, based on the findings of this study suggested using the exercise’s beneficial effects for prevention of the cardiac cell death in OVR.D animals.

Effects of Pseudomonas aeruginosa on Microglial-Derived Extracellular Vesicle Biogenesis and Composition

The packaging of molecular constituents inside extracellular vesicles (EVs) allows them to participate in intercellular communication and the transfer of biological molecules, however the role of EVs during bacterial infection is poorly understood. The goal of this study was to examine the effects of Pseudomonas aeruginosa (P. aeruginosa) infection on the biogenesis and composition of EVs derived from the mouse microglia cell line, BV-2. BV-2 cells were cultured in exosome-free media and infected with 0, 1.3 × 10⁴, or 2.6 × 10⁴ colony forming units per milliliter P. aeruginosa for 72 h. The results indicated that compared with the control group, BV-2 cell viability significantly decreased after P. aeruginosa infection and BV-2-derived EVs concentration decreased significantly in the P. aeruginosa-infected group. P. aeruginosa infection significantly decreased chemokine ligand 4 messenger RNA in BV-2-derived infected EVs, compared with the control group (p ≤ 0.05). This study also revealed that heat shock protein 70 (p ≤ 0.05) and heat shock protein 90β (p ≤ 0.001) levels of expression within EVs increased after P. aeruginosa infection. EV treatment with EVs derived from P. aeruginosa infection reduced cell viability of BV-2 cells. P. aeruginosa infection alters the expression of specific proteins and mRNA in EVs. Our study suggests that P. aeruginosa infection modulates EV biogenesis and composition, which may influence bacterial pathogenesis and infection.

Exercise as A Potential Therapeutic Target for Diabetic Cardiomyopathy: Insight into the Underlying Mechanisms

Diabetes mellitus is associated with cardiovascular, ophthalmic, and renal comorbidities. Among these, diabetic cardiomyopathy (DCM) causes the most severe symptoms and is considered to be a major health problem worldwide. Exercise is widely known as an effective strategy for the prevention and treatment of many chronic diseases. Importantly, the onset of complications arising due to diabetes can be delayed or even prevented by exercise. Regular exercise is reported to have positive effects on diabetes mellitus and the development of DCM. The protective effects of exercise include prevention of cardiac apoptosis, fibrosis, oxidative stress, and microvascular diseases, as well as improvement in cardiac mitochondrial function and calcium regulation. This review summarizes the recent scientific findings to describe the potential mechanisms by which exercise may prevent DCM and heart failure.

miR-1, miR-499 and miR-208 are sensitive markers to diagnose sudden death due to early acute myocardial infarction

MicroRNAs (miRNAs) are strongly up-regulated under pathological stress and in a wide range of diseases. In recent years, miRNAs are under investigation for their potential use as biomarkers in cardiovascular diseases. We investigate whether specific cardio-miRNAs are overexpressed in heart samples from subjects deceased for acute myocardial infarction (AMI) or sudden cardiac death (SCD), and whether miRNA could help differentiate between them. Forty four cases of death due to cardiovascular disease were selected, respectively, 19 cases categorized as AMI and 25 as SCD. Eighteen cases of traumatic death without pathological cardiac involvement were selected as control. Immunohistochemical investigation was performed for CD15, IL-15, Cx43, MCP-1, tryptase, troponin C and troponin I. Reverse transcription and quantitative real-time PCR were performed for miR-1, miR-133, miR-208 and miR-499. In AMI group, stronger immunoreaction for the CD15, IL-15 and MCP-1 antibodies was detectable compared with SCD and control. Cx43 showed a negative reaction with respect to the other groups. Real-time PCR results showed a down-regulation of all miRNAs in the AMI group compared with SCD and control. The selected miRNAs presented high accuracy in discriminating SCD from AMI (miR-1 and miR-499) and AMI from control (miR-208) representing a potential aid for both clinicians and pathologists for differential diagnosis.

Non-coding RNA involvement in the pathogenesis of diabetic cardiomyopathy

In recent years, the incidence of diabetes has been increasing rapidly, which seriously endangers human health. Diabetic cardiomyopathy, an important cardiovascular complication of diabetes, is characterized by myocardial fibrosis, ventricular remodelling and cardiac dysfunction. It has been documented that mitochondrial dysfunction, oxidative stress, inflammatory response, autophagy, apoptosis, diabetic microangiopathy and myocardial fibrosis are implicated in the pathogenesis of diabetic cardiomyopathy. With the development of molecular biology technology, accumulating evidence demonstrates that non‐coding RNAs (ncRNAs) are critically involved in the molecular mechanisms of diabetic cardiomyopathy. In this review, we summarize the pathological roles of three types of ncRNAs (microRNA, long ncRNA and circular RNA) in the progression of diabetic cardiomyopathy, which may provide valuable insights into the pathogenesis of diabetic cardiovascular complications.

Association between miR-499 rs3746444 polymorphism and coronary heart disease susceptibility: An evidence-based meta-analysis of 5063 cases and 4603 controls

MicroRNA-499 (miR-499) rs3746444 polymorphism has been associated with the risk of coronary heart disease (CHD). However, results from several studies are inconsistent. This meta-analysis aimed to further investigate the possible association between miR-499 rs3746444 polymorphism and CHD risk. A total of 9 case-control studies included 5063 CHD cases and 4603 healthy subjects. The A allele at rs374644 was associated with significantly decreased CHD risk in the total population according to the allelic model (OR = 0.80, 95% CI = 0.68-0.93, P = 0.005), homozygous model (OR = 0.52, 95% CI = 0.39-0.71, P < 0.001) and heterozygous model (OR = 0.57, 95% CI = 0.43-0.77, P < 0.001). A similar trend was found specifically in Asian and Chinese populations. In contrast, the wild-type GG genotype at rs374644 was associated with significantly increased CHD risk in the total population, according to the dominant model (OR = 1.83, 95% CI = 1.39-2.42, P < 0.001), and a similar trend was found in Asian and Chinese populations. These results indicate that in the total population, as well as in Asian and Chinese populations, the wild-type GG genotype at rs374644 may be related to increased susceptibility to CHD, while the A allele may be protective against CHD.

The protection of resveratrol and its combination with glibenclamide, but not berberine on the diabetic hearts against reperfusion-induced arrhythmias: the role of myocardial KATP channel

CONTEXT

Cardiovascular dysfunctions such as life-threatening arrhythmias are one of the main reasons of mortality and morbidity in diabetic patients Objective: We aimed to investigate the long-term effects of resveratrol, berberine and glibenclamide combinations on the ischemia/reperfusion (I/R) induced arrhythmias in streptozotocin (STZ)-induced diabetic rats and to investigate the role of myocardial K_ATP channel in the possible anti-arrhythmic actions of the treatments.

METHODS

Two days after induction of diabetes, diabetic rats were treated with resveratrol [5 mg/kg, intraperitoneally (i.p.)], berberine (10 mg/kg, i.p) and glibenclamide (5 mg/kg, i.p) for 6 weeks. On the 43th day, experimental animals were subjected to 6-min ischemia and 6-min reperfusion in vivo.

RESULTS

The protein expression of Kir6.2 subunits was downregulated in the diabetic hearts. However, all drug treatments restored the protein expression of Kir6.2 subunits. Resveratrol alone and its combination with glibenclamide decreased the arrhythmia score, the arrhythmic period and the incidence of other types of arrhythmias during the reperfusion period.

CONCLUSIONS

The combination of resveratrol with glibenclamide may alleviate reperfusion-induced arrhythmias via an underlying mechanism not be only associated with the restoration of the protein expression of Kir6.2 subunits but also associated with the other subunits or ion channels underlying cardiac action potential.

Sex Differences in Plasma MicroRNA Biomarkers of Early and Complicated Diabetes Mellitus in Israeli Arab and Jewish Patients

MicroRNAs play functional roles in the etiology of type 2 diabetes mellitus (T2DM) and complications, and extracellular microRNAs have attracted interest as potential biomarkers of these conditions. We aimed to identify a set of plasma microRNAs, which could serve as biomarkers of T2DM and complications in a mixed Israeli Arab/Jewish patient sample. Subjects included 30 healthy volunteers, 29 early-stage T2DM patients, and 29 late-stage T2DM patients with renal and/or vascular complications. RNA was isolated from plasma, and the levels of 12 candidate microRNAs were measured by quantitative reverse transcription and polymerase chain reaction (qRT-PCR). MicroRNA levels were compared between the groups and correlated to clinical measurements, followed by stepwise regression analysis and discriminant analysis. Plasma miR-486-3p and miR-423 were respectively up- and down-regulated in T2DM patients compared to healthy controls. MiR-28-3p and miR-423 were up-regulated in patients with complicated T2DM compared to early T2DM, while miR-486-3p was down-regulated. Combined, four microRNAs (miR-146a-5p, miR-16-2-3p, miR-126-5p, and miR-30d) could distinguish early from complicated T2DM with 77% accuracy and 79% sensitivity. In male patients only, the same microRNAs, with the addition of miR-423, could distinguish early from complicated T2DM with 83.3% accuracy. Furthermore, plasma microRNA levels showed significant correlations with clinical measurements, and these differed between men and women. Additionally, miR-183-5p levels differed significantly between the ethnic groups. Our study identified a panel of specific plasma microRNAs which can serve as biomarkers of T2DM and its complications and emphasizes the importance of sex differences in their clinical application.

Acute Weight Loss Restores Dysregulated Circulating MicroRNAs in Individuals Who Are Obese

CONTEXT

Obesity is a global epidemic and an independent risk factor for several diseases. miRNAs are gaining interest as early molecular regulators of various pathological processes.

OBJECTIVE

To examine the miRNA signatures in women who are obese and determine the response of miRNAs to acute weight loss.

METHODS

Plasma samples were collected from women who are obese (n = 80) before and after acute weight loss (mean, 7.2%). Plasma samples from age-matched lean volunteers (n = 80) were used as controls. Total RNA was extracted from the plasma samples and subjected to NanoString analysis of 822 miRNAs. The expression level of candidate miRNAs was validated in all participants using quantitative real-time PCR analysis.

RESULTS

NanoString analysis identified substantial dysregulation of 21 miRNAs in women who are obese that were associated with impaired glucose tolerance, senescence, cardiac hypertrophy, angiogenesis, inflammation, and cell death. Acute weight loss reversed the expression pattern of 18 of these miRNAs toward those seen in the lean control group. Furthermore, real-time PCR validation of all the samples for 13 miRNAs with at least twofold upregulation or downregulation confirmed substantial dysregulation of all the chosen miRNAs in women who are obese at baseline. After acute weight loss, the levels of seven miRNAs in women who are obese and who are lean were comparable, with no statistically significant evidence for differences between the two groups.

CONCLUSIONS

Our study has provided evidence that the circulating miRNAs associated with various disorders are dysregulated in women who are obese. We also found that seven of these miRNAs showed levels comparable to those in lean controls after acute weight loss in women who are obese.

Regulation of Chemokines and Cytokines by Histone Deacetylases and an Update on Histone Decetylase Inhibitors in Human Diseases

Histone acetyltransferases (HATs) and histone deacetylases (HDACs) counteract with each other to regulate gene expression by altering chromatin structure. Aberrant HDAC activity was reported in many human diseases including wide range of cancers, viral infections, cardiovascular complications, auto-immune diseases and kidney diseases. HDAC inhibitors are small molecules designed to block the malignant activity of HDACs. Chemokines and cytokines control inflammation, immunological and other key biological processes and are shown to be involved in various malignancies. Various HDACs and HDAC inhibitors were reported to regulate chemokines and cytokines. Even though HDAC inhibitors have remarkable anti-tumor activity in hematological cancers, they are not effective in treating many diseases and many patients relapse after treatment. However, the role of HDACs and cytokines in regulating these diseases still remain unclear. Therefore, understanding exact mechanisms and effector functions of HDACs are urgently needed to selectively inhibit them and to establish better a platform to combat various malignancies. In this review, we address regulation of chemokines and cytokines by HDACs and HDAC inhibitors and update on HDAC inhibitors in human diseases.

Early dysregulation of cardiac-specific microRNA-208a is linked to maladaptive cardiac remodelling in diabetic myocardium

Background

The diabetic heart undergoes remodelling contributing to an increased incidence of heart failure in individuals with diabetes at a later stage. The molecular regulators that drive this process in the diabetic heart are still unknown.

Methods

Real-time (RT) PCR analysis was performed to determine the expression of cardiac specific microRNA-208a in right atrial appendage (RAA) and left ventricular (LV) biopsy tissues collected from diabetic and non-diabetic patients undergoing coronary artery bypass graft surgery. To determine the time-dependent changes, cardiac tissue were collected from type 2 diabetic mice at different age groups. A western blotting analysis was conducted to determine the expression of contractile proteins α- and β-myosin heavy chain (MHC) and thyroid hormone receptor-α (TR-α), the negative regulator of β-MHC. To determine the beneficial effects of therapeutic modulation of miR-208a, high glucose treated adult mouse HL-1 cardiomyocytes were transfected with anti-miR-208a.

Results

RT-PCR analysis showed marked upregulation of miR-208a from early stages of diabetes in type 2 diabetic mouse heart, which was associated with a marked increase in the expression of pro-hypertrophic β-MHC and downregulation of TR-α. Interestingly, upregulation of miR-208a preceded the switch of α-/β-MHC isoforms and the development of diastolic and systolic dysfunction. We also observed significant upregulation of miR-208a and modulation of miR-208a associated proteins in the type 2 human diabetic heart. Therapeutic inhibition of miR-208a activity in high glucose treated HL-1 cardiomyocytes prevented the activation of β-MHC and hence the hypertrophic response.

Conclusion

Our results provide the first evidence that early modulation of miR-208a in the diabetic heart induces alterations in the downstream signaling pathway leading to cardiac remodelling and that therapeutic inhibition of miR-208a may be beneficial in preventing diabetes-induced adverse remodelling of the heart.

miRNA-1, miRNA-145 as a Myocardial Infarction Diagnostic Biomarker

Many myocardial infarction biomarkers currently available but they are a lack of specificity, therefore present study suggests to evaluate the significant importance of miRNA-1, miRNA-145 as biomarkers for early diagnosis of myocardial infarction. A blood sample was collected from three groups. The first group was patients with acute myocardial infarction (MI), the Second group was patients who have a risk factor for MI, and the Third group included healthy volunteers. Serum blood of this sample used to RNA purification and cDNA application with stem-loop specific primer then miRNA-1, and miRNA-145 was quantitated by using RT-PCR. The level of miR-1 fold change was significantly highest in the MI group followed by risk group and then by control group (P<0.05). while of miRNA-145 fold change was significantly lowest in the MI group followed by risk group and then by control group (P<0.05). A receiver operator characteristic (ROC) analysis; the cut off value was identified at miRNA-1 of >5.28 fold change with a sensitivity of 91.67 % and a specificity of 90.7%, while the cut off value of miRNA-145 has cut off ≤ 0.7 fold change with a sensitivity of 95.83 % and a specificity of 89.47%. miRNA-1, miR145 has high sensitivity and Specificity in this study which was bushed to using them as an alone biomarker or supported for Another biomarker in AMI diagnosis.

Molecular mechanism of diabetic cardiomyopathy and modulation of microRNA function by synthetic oligonucleotides

Diabetic cardiomyopathy (DCM) is a chronic complication in individuals with diabetes and is characterized by ventricular dilation and hypertrophy, diastolic dysfunction, decreased or preserved systolic function and reduced ejection fraction eventually resulting in heart failure. Despite being well characterized, the fundamental mechanisms leading to DCM are still elusive. Recent studies identified the involvement of small non-coding small RNA molecules such as microRNAs (miRs) playing a key role in the etiology of DCM. Therefore, miRs associated with DCM represents a new class of targets for the development of mechanistic therapeutics, which may yield marked benefits compared to other therapeutic approaches. Indeed, few miRs currently under active clinical investigation, with many expressing cautious optimism that miRs based therapies will succeed in the coming years. The major caution in using miRs based therapy is the need to improve the stability and specificity following systemic injection, which can be achieved through chemical and structural modification. In this review, we first discuss the established role of miRs in DCM and the advances in miRs based therapeutic strategies for the prevention/treatment of DCM. We next discuss the currently employed chemical modification of miR oligonucleotides and their utility in therapies specifically focusing on the DCM. Finally, we summarize the commonly used delivery system and approaches for assessment of miRNA modulation and potential off-target effects.

CCAAT/enhancer binding protein homologous protein knockdown alleviates hypoxia-induced myocardial injury in rat cardiomyocytes exposed to high glucose

Diabetic patients are more sensitive to ischemic injury than non-diabetics. Endoplasmic reticulum (ER) stress has been reported to be closely associated with the pathophysiology of ischemic injury in diabetes. The aim of the present study was to investigate the mechanisms involved in the progression of diabetes complicated by myocardial infarction (MI) and further verify the role of CCAAT/enhancer binding protein (C/EBP)-homologous protein (CHOP) using an in vitro model of diabetes/MI. The rats were exposed to 65 mg/kg streptozotocin (STZ) and left anterior descending (LAD) coronary artery ligation. ST-segment elevation, heart rate, left ventricular systolic pressure (LVSP) and LV end-diastolic pressure (LVEDP) were measured. Serum creatinine kinase-MB (CK-MB) and cardiac troponin T (cTnT) levels were examined by ELISA. Infarct size and apoptosis were measured by triphenyltetrazolium chloride staining and terminal deoxynucleotidyl-transferase-mediated dUTP nick end labeling assay. Pathological changes were evaluated by hematoxylin and eosin staining. H9c2 cells were used to establish an in vitro model of diabetes complicated by MI. Following CHOP knockdown, cell viability, cell cycle distribution and apoptosis were examined by Cell Counting Kit-8 assay, flow cytometry and Hoechst staining. Glucose-regulated protein 78 (GRP78), CHOP, B-cell lymphoma 2 (Bcl-2), Bcl-2-associated X protein (Bax), endoplasmic reticulum oxidoreductase 1 (Ero1)-α, Ero1β and protein disulfide isomerase (PDI) levels in both myocardial tissues and H9c2 cells were determined by western blotting. In the present study, diabetes complicated by MI promoted ST-segment elevation and myocardial apoptosis, increased infarct size, induced pathological changes and elevated LVEDP, CK-MB, cTnT, GRP78, CHOP, Bax, Ero1α, Ero1β and PDI; however, it decreased heart rate, LVSP and Bcl-2. Additionally, high glucose combined with hypoxic treatment reduced cell viability, induced cell cycle arrest at G1 phase, promoted cell apoptosis, and activated the GRP78/CHOP and Ero1/PDI signaling pathways, which were reversed by CHOP knockdown. Thus, CHOP may be an effective therapeutic target for the treatment of diabetes complicated by MI.

MicroRNA-19a contributes to the epigenetic regulation of tissue factor in diabetes

Background

Diabetes mellitus is characterized by chronic vascular disorder and presents a main risk factor for cardiovascular mortality. In particular, hyperglycaemia and inflammatory cytokines induce vascular circulating tissue factor (TF) that promotes pro-thrombotic conditions in diabetes. It has recently become evident that alterations of the post-transcriptional regulation of TF via specific microRNA(miR)s, such as miR-126, contribute to the pathogenesis of diabetes and its complications. The endothelial miR-19a is involved in vascular homeostasis and atheroprotection. However, its role in diabetes-related thrombogenicity is unknown. Understanding miR-networks regulating procoagulability in diabetes may help to develop new treatment options preventing vascular complications.

Methods and results

Plasma of 44 patients with known diabetes was assessed for the expression of miR-19a, TF protein, TF activity, and markers for vascular inflammation. High miR-19a expression was associated with reduced TF protein, TF-mediated procoagulability, and vascular inflammation based on expression of vascular adhesion molecule-1 and leukocyte count. We found plasma expression of miR-19a to strongly correlate with miR-126. miR-19a reduced the TF expression on mRNA and protein level in human microvascular endothelial cells (HMEC) as well as TF activity in human monocytes (THP-1), while anti-miR-19a increased the TF expression. Interestingly, miR-19a induced VCAM expression in HMEC. However, miR-19a and miR-126 co-transfection reduced total endothelial VCAM expression and exhibited additive inhibition of a luciferase reporter construct containing the F3 3′UTR.

Conclusions

While both miRs have differential functions on endothelial VCAM expression, miR-19a and miR-126 cooperate to exhibit anti-thrombotic properties via regulating vascular TF expression. Modulating the post-transcriptional control of TF in diabetes may provide a future anti-thrombotic and anti-inflammatory therapy.

Electronic supplementary material

The online version of this article (10.1186/s12933-018-0678-z) contains supplementary material, which is available to authorized users.

Type 2 Diabetes Mellitus and Cardiovascular Disease: Genetic and Epigenetic Links

Type 2 diabetes mellitus (DM) is a common metabolic disorder predisposing to diabetic cardiomyopathy and atherosclerotic cardiovascular disease (CVD), which could lead to heart failure through a variety of mechanisms, including myocardial infarction and chronic pressure overload. Pathogenetic mechanisms, mainly linked to hyperglycemia and chronic sustained hyperinsulinemia, include changes in metabolic profiles, intracellular signaling pathways, energy production, redox status, increased susceptibility to ischemia, and extracellular matrix remodeling. The close relationship between type 2 DM and CVD has led to the common soil hypothesis, postulating that both conditions share common genetic and environmental factors influencing this association. However, although the common risk factors of both CVD and type 2 DM, such as obesity, insulin resistance, dyslipidemia, inflammation, and thrombophilia, can be identified in the majority of affected patients, less is known about how these factors influence both conditions, so that efforts are still needed for a more comprehensive understanding of this relationship. The genetic, epigenetic, and environmental backgrounds of both type 2 DM and CVD have been more recently studied and updated. However, the underlying pathogenetic mechanisms have seldom been investigated within the broader shared background, but rather studied in the specific context of type 2 DM or CVD, separately. As the precise pathophysiological links between type 2 DM and CVD are not entirely understood and many aspects still require elucidation, an integrated description of the genetic, epigenetic, and environmental influences involved in the concomitant development of both diseases is of paramount importance to shed new light on the interlinks between type 2 DM and CVD. This review addresses the current knowledge of overlapping genetic and epigenetic aspects in type 2 DM and CVD, including microRNAs and long non-coding RNAs, whose abnormal regulation has been implicated in both disease conditions, either etiologically or as cause for their progression. Understanding the links between these disorders may help to drive future research toward an integrated pathophysiological approach and to provide future directions in the field.

Inhibition of microRNA‑155 ameliorates cardiac fibrosis in the process of angiotensin II‑induced cardiac remodeling

Cardiac fibrosis triggered by pressure overload represents one of the major challenges in the treatment of cardiovascular diseases. MicroRNA (miRNA/miR)-155, a member of the small RNA family, has previously been demonstrated to be associated with cardiac inflammation. However, the effect of miR-155 on cardiac fibrosis induced by angiotensin II (Ang II), particularly in cardiac fibroblasts, requires further investigation. The present study aimed to investigate the effect of miR-155 in Ang II-induced cardiac fibrosis using animal models and cardiac fibroblasts. Animal models were established in male miR-155^−/− and wild-type (WT) C57Bl/6J mice (10–12 weeks old) by Ang II infusion using subcutaneously implanted minipumps. After 8 weeks of Ang II infusion, the results demonstrated that the deletion of miR-155 in mice markedly ameliorated ventricular remodeling compared with WT mice, as demonstrated by restricted inflammatory responses, decreased heart size, improved cardiac function and reduced myocardial fibrosis. In vitro, overexpression of miR-155 in cardiac fibroblasts led to significantly increased fibroblast to myofibroblast transformation. However, this effect was abrogated by miR-155 silencing. In conclusion, the results of the present study indicate that genetic loss of miR-155 in mice ameliorates cardiac fibrotic remodeling following pressure overload. Therefore, inhibiting miR-155 may have potential as an adjunct to reduce cardiac inflammation in the treatment of cardiac fibrosis.

Regulatory RNAs and cardiovascular disease - with a special focus on circulating microRNAs

MicroRNAs (miRNAs) are a class of short non-coding regulatory RNA molecules which play an important role in intracellular communication and cell signaling and which influence cellular processes such as proliferation, differentiation, and cellular death. Over the past two decades, the crucial role of microRNAs in controlling tissue homeostasis and disease in cardiovascular systems has become widely recognized. By controlling the expression levels of their targets, several miRNAs have been shown to modulate the function of endothelial cells (miR-221/222 and -126), vascular smooth muscle cells (miR-143/145) and macrophages (miR-33, -758, and -26), thereby regulating the development and progression of atherosclerosis. The stability of miRNAs within the blood suggests that circulating miRNAs may function as important biomarkers of disease development and progression. Numerous circulating miRNAs have been found to be dysregulated in a wide variety of different disease states, including diabetes, cancer, and cardiovascular disease.

Implication of microRNAs in the development and potential treatment of radiation-induced heart disease

Radiotherapy is the most commonly used methodology to treat oncological disease, one of the most widespread causes of death worldwide. Oncological patients cured by radiotherapy applied to the mediastinal area have been shown to suffer from cardiovascular disease. The increase in the prevalence of radiation-induced heart disease has emphasized the need to seek new therapeutic targets to mitigate the negative impact of radiation on the heart. In this regard, microRNAs (miRNAs) have received considerable interest. miRNAs regulate post-transcriptional gene expression by their ability to target various mRNA sequences because of their imperfect pairing with mRNAs. It has been recognized that miRNAs modulate a diverse spectrum of cardiac functions with developmental, pathophysiological, and clinical implications. This makes them promising potential targets for diagnosis and treatment. This review summarizes the recent findings about the possible involvement of miRNAs in radiation-induced heart disease and their potential use as diagnostic or treatment targets in this respect.

MicroRNAs in dysfunctional adipose tissue: cardiovascular implications

In this review, we focus on the emerging role of microRNAs, non-coding RNAs that regulate gene expression and signaling pathways, in dysfunctional adipose tissue. We highlight current paradigms of microRNAs involved in adipose differentiation and function in depots such as white, brown, and beige adipose tissues and potential implications of microRNA dysregulation in human disease such as obesity, inflammation, microvasculature dysfunction, and related cardiovascular diseases. We highlight accumulating studies indicating that adipocyte-derived microRNAs may not only serve as biomarkers of cardiometabolic disease, but also may directly regulate gene expression of other tissues. Finally, we discuss the future prospects, challenges, and emerging strategies for microRNA delivery and targeting for therapeutic applications in cardiovascular disease states associated with adipocyte dysfunction.

Effect of fetal hypothyroidism on MyomiR network and its target gene expression profiles in heart of offspring rats

Thyroid hormone deficiency during fetal life (fetal hypothyroidism) causes intrauterine growth restriction (IUGR). Fetal hypothyroidism (FH) could attenuate normal cardiac functions in the later life of the offspring rats. The aim of this study was to evaluate the contribution of myomiR network and its target gene expression in cardiac dysfunction in fetal hypothyroid rats. Six Pregnant female rats were divided into two groups: Control consumed tap water, and the hypothyroid group received water containing 0.025% 6-propyl-2-thiouracil during gestation. Hearts from male offspring rats in adulthood (month 3) were tested with Langendorff apparatus for measuring hemodynamic parameters. Expressions of miR-208a, -208b, and -499 and its target genes including thyroid hormone receptor 1 (Thrap1), sex-determining region Y-box 6 (Sox6), and purine-rich element-binding protein β (Purβ) were measured by qPCR. FH rats had lower LVDP (%20), +dp/dt (%26), -dp/dt (%20), and heart rate (%21) than controls. FH rats at month 3 had a higher expression of β-MHC (190%), Myh7b (298%), and lower expression of α-MHC (36%) genes in comparison with controls. FH rats at month 3 had a higher expression of miR-499 (520%) and miR-208b (439%) and had lower expression of miR-208a (74%), Thrap1 (47%), Sox6 (49%), and Purβ (45%) compared with controls. Our results showed that thyroid hormone deficiency during fetal life changes the pattern of gene expression of myomiR network and its target genes in fetal heart, which, in turn, resulted in increased β-MHC expression and associated cardiac dysfunction in adulthood.