MiR-451 antagonist protects against cardiac fibrosis in streptozotocin-induced diabetic mouse heart

Unraveling the Cardiac Matrix: From Diabetes to Heart Failure, Exploring Pathways and Potential Medications

Myocardial infarction (MI) often leads to heart failure (HF) through acute or chronic maladaptive remodeling processes. This establishes coronary artery disease (CAD) and HF as significant contributors to cardiovascular illness and death. Therefore, treatment strategies for patients with CAD primarily focus on preventing MI and lessening the impact of HF after an MI event. Myocardial fibrosis, characterized by abnormal extracellular matrix (ECM) deposition, is central to cardiac remodeling. Understanding these processes is key to identifying new treatment targets. Recent studies highlight SGLT2 inhibitors (SGLT2i) and GLP-1 receptor agonists (GLP1-RAs) as favorable options in managing type 2 diabetes due to their low hypoglycemic risk and cardiovascular benefits. This review explores inflammation's role in cardiac fibrosis and evaluates emerging anti-diabetic medications' effectiveness, such as SGLT2i, GLP1-RAs, and dipeptidyl peptidase-4 inhibitors (DPP4i), in preventing fibrosis in patients with diabetes post-acute MI. Recent studies were analyzed to identify effective medications in reducing fibrosis risk in these patients. By addressing these areas, we can advance our understanding of the potential benefits of anti-diabetic medications in reducing cardiac fibrosis post-MI and improve patient outcomes in individuals with diabetes at risk of HF.

Epigenetic Regulation of EMP/EMT-Dependent Fibrosis

Fibrosis represents a process characterized by excessive deposition of extracellular matrix (ECM) proteins. It often represents the evolution of pathological conditions, causes organ failure, and can, in extreme cases, compromise the functionality of organs to the point of causing death. In recent years, considerable efforts have been made to understand the molecular mechanisms underlying fibrotic evolution and to identify possible therapeutic strategies. Great interest has been aroused by the discovery of a molecular association between epithelial to mesenchymal plasticity (EMP), in particular epithelial to mesenchymal transition (EMT), and fibrogenesis, which has led to the identification of complex molecular mechanisms closely interconnected with each other, which could explain EMT-dependent fibrosis. However, the result remains unsatisfactory from a therapeutic point of view. In recent years, advances in epigenetics, based on chromatin remodeling through various histone modifications or through the intervention of non-coding RNAs (ncRNAs), have provided more information on the fibrotic process, and this could represent a promising path forward for the identification of innovative therapeutic strategies for organ fibrosis. In this review, we summarize current research on epigenetic mechanisms involved in organ fibrosis, with a focus on epigenetic regulation of EMP/EMT-dependent fibrosis.

Endothelial-to-Mesenchymal Transition: Potential Target of Doxorubicin-Induced Cardiotoxicity

The use of chemotherapeutic agents is becoming more frequent as the proportion of new oncology patients increases worldwide, with prolonged survival after treatment. As one of the most popular chemotherapy drugs, doxorubicin plays a substantial role in the treatment of tumors. Unfortunately, the use of doxorubicin is associated with several adverse effects, particularly severe cardiotoxicity that can be life-threatening, which greatly limits its clinical use. For decades, scientists have tried to explore many cardioprotective agents and therapeutic approaches, but their efficacy remains controversial, and some drugs have even brought about significant adverse effects. The concrete molecular mechanism of doxorubicin-induced cardiotoxicity is still to be unraveled, yet endothelial damage is gradually being identified as an important mechanism triggering the development and progression of doxorubicin-induced cardiotoxicity. Endothelial-to-mesenchymal transition (EndMT), a fundamental process regulating morphogenesis in multicellular organisms, is recognized to be associated with endothelial damage repair and acts as an important factor in the progression of cardiovascular diseases, tumors, and rheumatic immune diseases. Mounting evidence suggests that endothelial-mesenchymal transition may play a non-negligible role in doxorubicin-induced cardiotoxicity. In this paper, we reviewed the molecular mechanisms and signaling pathways of EndMT and outlined the molecular mechanisms of doxorubicin-induced cardiotoxicity and the current therapeutic advances. Furthermore, we summarized the basic principles of doxorubicin-induced endothelial-mesenchymal transition that lead to endothelial dysfunction and cardiotoxicity, aiming to provide suggestions or new ideas for the prevention and treatment of doxorubicin-induced endothelial and cardiac injury.

Targeting epigenetics in diabetic cardiomyopathy: Therapeutic potential of flavonoids

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

Prophylactic administration of miR-451 inhibitor decreases osteoarthritis severity in rats

Transfection of chondrocytes with microRNA-451(miR-451), present in growth zone cartilage of the growth plate, upregulates production of enzymes association with extracellular matrix degradation. miR-451 is also present in articular cartilage and exacerbates IL-1β effects in articular chondrocytes. Moreover, when osteoarthritis (OA) was induced in Sprague Dawley rats via bilateral anterior cruciate ligament transection (ACLT), miR-451 expression was increased in OA cartilage compared to control, suggesting its inhibition might be used to prevent or treat OA. To examine the prophylactic and therapeutic potential of inhibiting miR-451, we evaluated treatment with miR-451 power inhibitor (451-PI) at the onset of joint trauma and treatment after OA had developed. The prophylactic animal cohort received twice-weekly intra-articular injections of either 451-PI or a negative control (NC-PI) beginning on post-surgical day 3. OA was allowed to develop for 24 days in the therapeutic cohort before beginning injections. All rats were killed on day 45. Micro-CT, histomorphometrics, OARSI scoring, and muscle force testing were performed on samples. 451-PI mitigated OA progression compared to NC-PI limbs in the prophylactic cohort based on histomorphometric analysis and OARSI scoring, but no differences were detected by micro-CT. 451-PI treatment beginning 24 days post-surgery was not able to reduce OA severity. Prophylactic administration of 451-PI mitigates OA progression in a post-trauma ACLT rat model supporting its potential to prevent OA development following an ACLT injury clinically.

The role of microRNAs in the pathophysiology, diagnosis, and treatment of diabetic cardiomyopathy

INTRODUCTION

Diabetic cardiomyopathy (DCM) is an end-point macrovascular complication associated with increased morbidity and mortality in 12% of diabetic patients. MicroRNAs (miRNAs) are small noncoding RNAs that can act as cardioprotective or cardiotoxic agents in DCM.

METHODS

We used PubMed as a search engine to collect and analyse data in published articles on the role of miRNAs on the pathophysiology, diagnosis and treatment of DCM.

RESULTS

MiRNAs play an essential role in the pathophysiology, diagnosis and treatment of DCM due to their distinct gene expression patterns in diabetic patients compared to healthy individuals. Advances in gene therapy have led to the discovery of potential circulating miRNAs, which can be used as biomarkers for DCM diagnosis and prognosis. Furthermore, targeted miRNA therapies in preclinical and clinical studies, such as using miRNA mimics and anti-miRNAs, have yielded promising results. Application of miRNA mimics and anti-miRNAs via different nanodrug delivery systems alleviate hypertrophy, fibrosis, oxidative stress and apoptosis of cardiomyocytes.

CONCLUSION

MiRNAs serve as attractive potential targets for DCM diagnosis, prognosis and treatment due to their distinctive expression profile in DCM development.

Relationship Between Circulating MicroRNAs and Left Ventricular Hypertrophy in Hypertensive Patients

Objective

Left ventricular hypertrophy (LVH) is a common complication of hypertension and microRNAs (miRNAs) are considered to play an important role in cardiac hypertrophy development. This study evaluated the relationship between circulating miRNAs and LVH in hypertensive patients.

Methods

Two cohorts [exploratory (n = 42) and validation (n = 297)] of hypertensive patients were evaluated by clinical, laboratory and echocardiography analysis. The serum expression of 754 miRNAs in the exploratory cohort and 6 miRNAs in the validation cohort was evaluated by the TaqMan OpenArray^® system and quantitative polymerase chain reaction, respectively.

Results

Among the 754 analyzed miRNAs, ten miRNAs (miR-30a-5p, miR-let7c, miR-92a, miR-451, miR-145-5p, miR-185, miR-338, miR-296, miR-375, and miR-10) had differential expression between individuals with and without LVH in the exploratory cohort. Results of multivariable regression analysis adjusted for confounding variables showed that three miRNAs (miR-145-5p, miR-451, and miR-let7c) were independently associated with LVH and left ventricular mass index in the validation cohort. Functional enrichment analysis demonstrated that these three miRNAs can regulate various genes and pathways related to cardiac remodeling. Furthermore, in vitro experiments using cardiac myocytes demonstrated that miR-145-5p mimic transfection up-regulated the expression of brain and atrial natriuretic peptide genes, which are markers of cardiac hypertrophy, while anti-miR-145-5p transfection abrogated the expression of these genes in response to norepinephrine stimulus.

Conclusions

Our data demonstrated that circulating levels of several miRNAs, in particular miR-145-5p, miR-451, and let7c, were associated with LVH in hypertensive patients, indicating that these miRNAS may be potential circulating biomarkers or involved in hypertension-induced LV remodeling.

Non-canonical features of microRNAs: paradigms emerging from cardiovascular disease

Research showing that microRNAs (miRNAs) are versatile regulators of gene expression has instigated tremendous interest in cardiovascular research. The overwhelming majority of studies are predicated on the dogmatic notion that miRNAs regulate the expression of specific target mRNAs by inhibiting mRNA translation or promoting mRNA decay in the RNA-induced silencing complex (RISC). These efforts mostly identified and dissected contributions of multiple regulatory networks of miRNA-target mRNAs to cardiovascular pathogenesis. However, evidence from studies in the past decade indicates that miRNAs also operate beyond this canonical paradigm, featuring non-conventional regulatory functions and cellular localizations that have a pathophysiological role in cardiovascular disease. In this Review, we highlight the functional relevance of atypical miRNA biogenesis and localization as well as RISC heterogeneity. Moreover, we delineate remarkable non-canonical examples of miRNA functionality, including direct interactions with proteins beyond the Argonaute family and their role in transcriptional regulation in the nucleus and in mitochondria. We scrutinize the relevance of non-conventional biogenesis and non-canonical functions of miRNAs in cardiovascular homeostasis and pathology, and contextualize how uncovering these non-conventional properties can expand the scope of translational research in the cardiovascular field and beyond.

Manipulation of the miR-378a/mt-ATP6 regulatory axis rescues ATP synthase in the diabetic heart and offers a novel role for lncRNA Kcnq1ot1

Diabetes mellitus has been linked to an increase in mitochondrial microRNA-378a (miR-378a) content. Enhanced miR-378a content has been associated with a reduction in mitochondrial genome-encoded mt-ATP6 abundance, supporting the hypothesis that miR-378a inhibition may be a therapeutic option for maintaining ATP synthase functionality during diabetes mellitus. Evidence also suggests that long noncoding RNAs (lncRNAs), including lncRNA potassium voltage-gated channel subfamily Q member 1 overlapping transcript 1 (Kcnq1ot1), participate in regulatory axes with microRNAs (miRs). Prediction analyses indicate that Kcnq1ot1 has the potential to bind miR-378a. This study aimed to determine if loss of miR-378a in a genetic mouse model could ameliorate cardiac dysfunction in type 2 diabetes mellitus (T2DM) and to ascertain whether Kcnq1ot1 interacts with miR-378a to impact ATP synthase functionality by preserving mt-ATP6 levels. MiR-378a was significantly higher in patients with T2DM and 25-wk-old Db/Db mouse mitochondria, whereas mt-ATP6 and Kcnq1ot1 levels were significantly reduced when compared with controls. Twenty-five-week-old miR-378a knockout Db/Db mice displayed preserved mt-ATP6 and ATP synthase protein content, ATP synthase activity, and preserved cardiac function, implicating miR-378a as a potential therapeutic target in T2DM. Assessments following overexpression of the 500-bp Kcnq1ot1 fragment in established mouse cardiomyocyte cell line (HL-1) cardiomyocytes overexpressing miR-378a revealed that Kcnq1ot1 may bind and significantly reduce miR-378a levels, and rescue mt-ATP6 and ATP synthase protein content. Together, these data suggest that Kcnq1ot1 and miR-378a may act as constituents in an axis that regulates mt-ATP6 content, and that manipulation of this axis may provide benefit to ATP synthase functionality in type 2 diabetic heart.

Research Progress on Epigenetics of Diabetic Cardiomyopathy in Type 2 Diabetes

Diabetic cardiomyopathy (DCM) is characterized by diastolic relaxation abnormalities in its initial stages and by clinical heart failure (HF) without dyslipidemia, hypertension, and coronary artery disease in its last stages. DCM contributes to the high mortality and morbidity rates observed in diabetic populations. Diabetes is a polygenic, heritable, and complex condition that is exacerbated by environmental factors. Recent studies have demonstrated that epigenetics directly or indirectly contribute to pathogenesis. While epigenetic mechanisms such as DNA methylation, histone modifications, and non-coding RNAs, have been recognized as key players in the pathogenesis of DCM, some of their impacts remain not well understood. Furthering our understanding of the roles played by epigenetics in DCM will provide novel avenues for DCM therapeutics and prevention strategies.

MicroRNA targets and biomarker validation for diabetes-associated cardiac fibrosis

Cardiac fibrosis is one of the main characteristics of diabetic cardiomyopathy and manifests excessive accumulation of extracellular matrix proteins in the heart. Several signaling pathways have been proposed for pathogenesis of cardiac fibrosis in the diabetic heart. TGF-β/Smad2/3-dependent or independent pathway is the major signaling molecule core in the pathogenesis of cardiac fibrosis. MicroRNAs (miRNAs, miR) are ~22-nuceotide regulatory RNAs that are involved in gene silencing through the degradation of post-transcriptional mRNA or suppression of the expressed proteins. Hyperglycemia in the diabetic heart regulates expression of some miRNAs. Target molecules of miRNAs can be identified through biocomputational database initial screening and dual luciferase assay validation. miR-21, miR-150-5p, miR-155, miR-216a-3p, miR-221-3p, miR-223, and miR-451 were up-regulated in the diabetic heart and promoted cardiac fibrosis through targeting signaling pathways in cardiac fibroblasts, endothelial cells, and cardiac myocytes. miR-15a/-15b, miR-18a-5p, miR-20a-5p, miR-26b-5p, miR-29, miR-133a, miR-141, miR-146, miR-200b, miR-203, miR-222, and miR-551b-5p were down-regulated in the diabetic heart and exhibited anti-fibrosis when they were overexpressed. miRNAs are stable molecules and may reflect the pathological changes of organs. Some miRNAs have been detected in the plasma or serum in patients with diabetes mellitus or heart failure. Exploration of targets and biomarkers of miRNA may provide additional information on pathogenesis and diagnosis of cardiac fibrosis and novel targets to tackle diabetic cardiomyopathy.

Role of miRNA and lncRNAs in organ fibrosis and aging

Fibrosis is the endpoint of pathological remodeling. This process contributes to the pathogenesis of several chronic disorders and aging-associated organ damage. Different molecular cascades contribute to this process. TGF-β, WNT, and YAP/TAZ signaling pathways have prominent roles in this process. A number of long non-coding RNAs and microRNAs have been found to regulate organ fibrosis through modulation of the activity of related signaling pathways. miR-144-3p, miR-451, miR-200b, and miR-328 are among microRNAs that participate in the pathology of cardiac fibrosis. Meanwhile, miR-34a, miR-17-5p, miR-122, miR-146a, and miR-350 contribute to liver fibrosis in different situations. PVT1, MALAT1, GAS5, NRON, PFL, MIAT, HULC, ANRIL, and H19 are among long non-coding RNAs that participate in organ fibrosis. We review the impact of long non-coding RNAs and microRNAs in organ fibrosis and aging-related pathologies.

Fibrosis of the diabetic heart: Clinical significance, molecular mechanisms, and therapeutic opportunities

In patients with diabetes, myocardial fibrosis may contribute to the pathogenesis of heart failure and arrhythmogenesis, increasing ventricular stiffness and delaying conduction. Diabetic myocardial fibrosis involves effects of hyperglycemia, lipotoxicity and insulin resistance on cardiac fibroblasts, directly resulting in increased matrix secretion, and activation of paracrine signaling in cardiomyocytes, immune and vascular cells, that release fibroblast-activating mediators. Neurohumoral pathways, cytokines, growth factors, oxidative stress, advanced glycation end-products (AGEs), and matricellular proteins have been implicated in diabetic fibrosis; however, the molecular links between the metabolic perturbations and activation of a fibrogenic program remain poorly understood. Although existing therapies using glucose- and lipid-lowering agents and neurohumoral inhibition may act in part by attenuating myocardial collagen deposition, specific therapies targeting the fibrotic response are lacking. This review manuscript discusses the clinical significance, molecular mechanisms and cell biology of diabetic cardiac fibrosis and proposes therapeutic targets that may attenuate the fibrotic response, preventing heart failure progression.

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

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

EndMT Regulation by Small RNAs in Diabetes-Associated Fibrotic Conditions: Potential Link With Oxidative Stress

Diabetes-associated complications, such as retinopathy, nephropathy, cardiomyopathy, and atherosclerosis, the main consequences of long-term hyperglycemia, often lead to organ dysfunction, disability, and increased mortality. A common denominator of these complications is the myofibroblast-driven excessive deposition of extracellular matrix proteins. Although fibroblast appears to be the primary source of myofibroblasts, other cells, including endothelial cells, can generate myofibroblasts through a process known as endothelial to mesenchymal transition (EndMT). During EndMT, endothelial cells lose their typical phenotype to acquire mesenchymal features, characterized by the development of invasive and migratory abilities as well as the expression of typical mesenchymal products such as α-smooth muscle actin and type I collagen. EndMT is involved in many chronic and fibrotic diseases and appears to be regulated by complex molecular mechanisms and different signaling pathways. Recent evidence suggests that small RNAs, in particular microRNAs (miRNAs) and long non-coding RNAs (lncRNAs), are crucial mediators of EndMT. Furthermore, EndMT and miRNAs are both affected by oxidative stress, another key player in the pathophysiology of diabetic fibrotic complications. In this review, we provide an overview of the primary redox signals underpinning the diabetic-associated fibrotic process. Then, we discuss the current knowledge on the role of small RNAs in the regulation of EndMT in diabetic retinopathy, nephropathy, cardiomyopathy, and atherosclerosis and highlight potential links between oxidative stress and the dyad small RNAs-EndMT in driving these pathological states.

MiR-21-3p triggers cardiac fibroblasts pyroptosis in diabetic cardiac fibrosis via inhibiting androgen receptor

AIMS/HYPOTHESIS

MicroRNA-21 has been implicated in diabetic complication, including diabetic cardiomyopathy. However, there is limited information regarding the biological role of the miR-21 passenger strand (miR-21-3p) in diabetic cardiac fibrosis. The aim of this study was to investigate the role of miR-21-3p and its target androgen receptor in STZ-induced diabetic cardiac fibrosis.

METHODS

The pathological changes and collagen depositions was analyzed by HE, Sirius Red staining and Masson's Trichrome Staining. MiR-21-3p, AR, NLRP3, caspase1 and collagen I expression were analyzed by western blotting, immunohistochemistry, immunofluorescence, qRT-PCR, miR one step qRT-PCR, respectively. A luciferase reporter assay was used to verify the interaction between miR-21 and the 3' untranslated region (3'UTR) of AR.

RESULTS

Our results indicated that miR-21-3p level was up-regulated, while AR was decreased in STZ-induced diabetic cardiac fibrosis tissues and cardiac fibroblast. High glucose triggers cardiac fibroblasts pyroptosis and collagen deposition. Gain-of-function and loss-of-function assays demonstrated that miR-21-3p mediated the crucial role in diabetic cardiac fibrosis. Our results show that miR-21-3p bound to the 3'UTR of AR post-transcriptionally repressed its expression. We also found AR, which regulates cardiac fibroblasts pyroptosis and collagen deposition through caspase1 signaling.

CONCLUSIONS

/interpretation: Taken together, our study showed that miR-21-3p aggravates STZ-induced diabetic cardiac fibrosis through the caspase1 pathways by suppressing AR expression.

Comprehensive analysis of differentially expressed microRNAs and mRNAs involved in diabetic corneal neuropathy

AIMS

Corneal nerve fibers are derived from the ophthalmic division of the trigeminal ganglion (TG). Here, by sequencing of microRNAs (miRNAs) and messenger RNAs (mRNAs) from diabetic and normal TG tissues, we aimed to uncover potential miRNAs, mRNAs, and the network of their interactions involved in the pathogenesis of diabetic corneal neuropathy.

MAIN METHODS

We performed RNA sequencing to systematically screen out differentially expressed miRNAs and mRNAs in TG tissues from diabetic and normal mice. Functional enrichment analyses were performed to illustrate the biological functions of differentially expressed mRNAs (DEmRNAs). Following this, miRNA-mRNA regulatory networks were built by means of bioinformatics methods to suggest regulatory role for miRNAs in the pathogenesis of diabetic corneal neuropathy. Finally, the credibility of the sequencing-based results was validated using qRT-PCR.

KEY FINDINGS

Sequencing analyses disclosed that 68 miRNAs and 114 mRNAs were differentially expressed in diabetic TG tissues compared with normal TG samples. The functional analyses showed that DEmRNAs participated in diabetes-related biological processes. After applying an optimized approach to predict miRNA-mRNA pairs, a miRNA-mRNA interacting network was inferred. Subsequently, the expression and correlation of miR-350-5p and Mup20, miR-592-5p and Angptl7 as well as miR-351-5p and Elovl6 were preliminarily validated.

SIGNIFICANCE

Our study provides a systematic characterization of miRNA and mRNA expression in the TG during diabetic corneal neuropathy and will contribute to the development of clinical diagnostic and therapeutic strategies for diabetic corneal neuropathy.

Inhibition of miR-223 attenuates the NLRP3 inflammasome activation, fibrosis, and apoptosis in diabetic cardiomyopathy

Diabetic cardiomyopathy (DCM) is an independent and specific cardiomyopathy, which is associated with cardiac failure in diabetic patients. Currently, the pathogenesis of DCM is a popular research topic in the investigation of cardiovascular diseases. MicroRNAs (miRNAs) have been identified as the latent therapeutic targets for DCM. However, the functions and complex mechanisms of miRNAs in DCM have not been clarified. The cardiomyocyte injury model was established using high glucose (HG) ingestion, and the DCM rat model was established using 30 mg/kg streptozotocin. MicroRNA-223 (miR-223) expression was determined using qRT-PCR; the levels of NLRP3 inflammasome, fibrosis, and apoptosis-related genes and proteins were analyzed using qRT-PCR and western blot assays. Besides the morphological changes and fibrosis of myocardial tissues were evaluated using H&E and Masson staining. We discovered that miR-223 was highly expressed in the HG-induced cardiomyocyte injury model, and miR-223 inhibitor could further relieve the myocardial fibrosis and apoptosis, and inhibit NLRP3 inflammasome of HG-induced H9c2 cells. Additionally, we found that inhibition of miR-223 had obvious positive effects on the cardiac dysfunction and reduced the elevation of blood sugar in the DCM model rats. We found that the miRNA-223 inhibitor could improve the morphological structure and the degree of fibrosis in myocardial tissues in the DCM model rats. Moreover, we verified that inhibition of miR-223 could suppress the NLRP3 inflammasome activation, and alleviate myocardial fibrosis and apoptosis of the DCM model rats. In conclusion, our results suggested that miR-223 might be an underlying therapeutic target for DCM by reducing NLRP3 inflammasome activation, fibrosis, and apoptosis.

MiRNA-451a inhibits airway remodeling by targeting Cadherin 11 in an allergic asthma model of neonatal mice

Airway remodeling happens in childhood asthma, in parallel with, but not necessarily subsequent to, airway inflammation. The differentiation of airway epithelial cells into myofibroblasts via epithelial-mesenchymal-transition (EMT) is one of the mechanisms underlying airway remodeling. This study aimed at identifying novel molecules involved in pediatric asthma-associated airway remodeling. Asthma model was established by challenging C57BL/6 mouse pups with ovalbumin (OVA). We found that the expression of Cadherin 11 (CDH11), a type II cadherin, was increased by OVA treatments in the airway epithelium. Our earlier microarray data suggested miRNA-451a-5p (miRNA-451a) as a potential regulator of CDH11. In contrast to CDH11, miRNA-451a expression decreased in the asthmatic lung. MiRNA-451a was then packaged into a lentivirus vector and systematically given to the asthmatic pups. Our data indicated that OVA-induced infiltration of inflammatory cells, including eosnophils, neutrophils, macrophages and lymphocytes, was reduced by miRNA-451a over-expression. EMT was initiated in asthmatic mice as demonstrated by increased alpha-smooth muscle actin (α-SMA) positive cells present in airway epithelium, which was inhibited by miRNA-451a. CDH11 elevation in vivo was also inhibited by miRNA-451a. Dual-Luciferase analysis further showed CDH11 as a novel valid target of miRNA-451a. Additionally, in vitro, EMT was triggered in human 16HBE airway epithelial cells by pro-fibrotic transforming growth factor β (TGF-β). Corresponding to the anti-EMT effects observed in vivo, miRNA-451a also inhibited TGF-β-induced collagen deposition in cultured airway epithelial cells by targeting in CDH11. In summary, our study demonstrates that the deregulated miRNA-451a-CDH11 axis contributes to airway remodeling in childhood asthma.

Epigenetic Regulation Associated With Sirtuin 1 in Complications of Diabetes Mellitus

Diabetes mellitus (DM) has been one of the largest health concerns of the 21st century due to the serious complications associated with the disease. Therefore, it is essential to investigate the pathogenesis of DM and develop novel strategies to reduce the burden of diabetic complications. Sirtuin 1 (SIRT1), a nicotinamide adenosine dinucleotide (NAD⁺)-dependent deacetylase, has been reported to not only deacetylate histones to modulate chromatin function but also deacetylate numerous transcription factors to regulate the expression of target genes, both positively and negatively. SIRT1 also plays a crucial role in regulating histone and DNA methylation through the recruitment of other nuclear enzymes to the chromatin. Furthermore, SIRT1 has been verified as a direct target of many microRNAs (miRNAs). Recently, numerous studies have explored the key roles of SIRT1 and other related epigenetic mechanisms in diabetic complications. Thus, this review aims to present a summary of the rapidly growing field of epigenetic regulatory mechanisms, as well as the epigenetic influence of SIRT1 on the development and progression of diabetic complications, including cardiomyopathy, nephropathy, and retinopathy.

Overexpression of microRNA-216a-3p Accelerates the Inflammatory Response in Cardiomyocytes in Type 2 Diabetes Mellitus by Targeting IFN-α2

Background: Type 2 diabetes mellitus (T2DM) is a chronic, hyperglycemia-associated, metabolic disorder. Heart disease is a major complication of T2DM. The present study aimed to explore the effects of miR-216a-3p on cardiomyocyte proliferation, apoptosis, and inflammation in T2DM through the Toll-like receptor (TLR) pathway involving interferon-α2 (IFN-α2) mediation. Methods: T2DM was induced in rats by a high-fat diet, in combination with an intraperitoneal injection of low-dose streptozotocin. ELISAs were conducted to measure inflammatory-related factors in serum. Next, isolated cardiomyocytes were used in loss- and gain-of-function experiments, followed by MTT and flow cytometry assays, conducted to evaluate cell proliferation, cell cycle, and apoptosis. Results: Our results revealed an increase in the inflammatory response in T2DM rat models, accompanied by significantly increased expression of miR-216a-3p and TLR pathway-related genes. However, a decrease in the expression of IFN-α2 was observed. Moreover, the presence of an miR-216a-3p inhibitor and si-IFN-α2 increased the expression of TLR pathway-related genes and cell apoptosis, whereas cell proliferation was significantly decreased in the cardiomyocytes. Conclusion: We found that in T2DM, miR-216a-3p inhibited the proliferation and enhanced the apoptosis of cardiomyocytes and generated an inflammatory response through activation of the TLR pathway and targeting of IFN-α2.

MiR-144 protects the heart from hyperglycemia-induced injury by regulating mitochondrial biogenesis and cardiomyocyte apoptosis

Several lines of evidence have revealed the potential of microRNAs (miRNAs, miRs) as biomarkers for detecting diabetic cardiomyopathy, although their functions in hyperglycemic cardiac dysfunction are still lacking. In this study, mitochondrial biogenesis was markedly impaired induced by high glucose (HG), as evidenced by dysregulated mitochondrial structure, reduced mitochondrial DNA contents, and biogenesis-related mRNA levels, accompanied by increased cell apoptosis. MiR-144 was identified to be decreased in HG-induced cardiomyocytes and in streptozotocin (STZ)-challenged heart samples. Forced miR-144 expression enhanced mitochondrial biogenesis and suppressed cell apoptosis, while miR-144 inhibition exhibited the opposite results. Rac-1 was identified as a target gene of miR-144. Decreased Rac-1 levels activated AMPK phosphorylation and PGC-1α deacetylation, leading to increased mitochondrial biogenesis and reduced cell apoptosis. Importantly, the systemic neutralization of miR-144 attenuated mitochondrial disorder and ventricular dysfunction following STZ treatment. Additionally, plasma miR-144 decreased markedly in diabetic patients with cardiac dysfunction. The receiver-operator characteristic curve showed that plasma miR-144 could specifically predict diabetic patients developing cardiac dysfunction. In conclusion, this study provides strong evidence suggesting that miR-144 protects heart from hyperglycemia-induced injury by improving mitochondrial biogenesis and decreasing cell apoptosis via targeting Rac-1. Forced miR-144 expression might, thus, be a protective strategy for treating hyperglycemia-induced cardiac dysfunction.

New Insights for Cellular and Molecular Mechanisms of Aging and Aging-Related Diseases: Herbal Medicine as Potential Therapeutic Approach

Aging is a progressive disease affecting around 900 million people worldwide, and in recent years, the mechanism of aging and aging-related diseases has been well studied. Treatments for aging-related diseases have also made progress. For the long-term treatment of aging-related diseases, herbal medicine is particularly suitable for drug discovery. In this review, we discuss cellular and molecular mechanisms of aging and aging-related diseases, including oxidative stress, inflammatory response, autophagy and exosome interactions, mitochondrial injury, and telomerase damage, and summarize commonly used herbals and compounds concerned with the development of aging-related diseases, including Ginkgo biloba, ginseng, Panax notoginseng, Radix astragali, Lycium barbarum, Rhodiola rosea, Angelica sinensis, Ligusticum chuanxiong, resveratrol, curcumin, and flavonoids. We also summarize key randomized controlled trials of herbal medicine for aging-related diseases during the past ten years. Adverse reactions of herbs were also described. It is expected to provide new insights for slowing aging and treating aging-related diseases with herbal medicine.

Connecting sex differences, estrogen signaling, and microRNAs in cardiac fibrosis

Sex differences are evident in the pathophysiology of heart failure (HF). Progression of HF is promoted by cardiac fibrosis and no fibrosis-specific therapies are currently available. The fibrotic response is mediated by cardiac fibroblasts (CFs), and a central event is their phenotypic transition to pro-fibrotic myofibroblasts. These myofibroblasts may arise from various cellular origins including resident CFs and epicardial and endothelial cells. Both female subjects in clinical studies and female animals in experimental studies generally present less cardiac fibrosis compared with males. This difference is at least partially considered attributable to the ovarian hormone 17β-estradiol (E2). E2 signals via estrogen receptors to regulate genes are involved in the fibrotic response and myofibroblast transition. Besides protein-coding genes, E2 also regulates transcription of microRNA that modulate cardiac fibrosis. Sex dimorphism, E2, and miRNAs form multi-level regulatory networks in the pathophysiology of cardiac fibrosis, and the mechanism of these networks is not yet fully deciphered. Therefore, this review is aimed at summarizing current knowledge on sex differences, E2, and estrogen receptors in cardiac fibrosis, emphasizing on microRNAs and myofibroblast origins. KEY MESSAGES: • E2 and ERs regulate cardiac fibroblast function. • E2 and ERs may distinctly affect male and female cardiac fibrosis pathophysiology. • Sex, E2, and miRNAs form multi-level regulatory networks in cardiac fibrosis. • Sex-dimorphic and E2-regulated miRNAs affect mesenchymal transition.