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

Role of apoptosis repressor with caspase recruitment domain in human health and chronic diseases

Apoptosis repressor with caspase recruitment domain (ARC) is a highly potent and multifunctional suppressor of various types of programmed cell death (PCD) (e.g. apoptosis, necroptosis, and pyroptosis) and plays a key role in determining cell fate. Under physiological conditions, ARC is predominantly expressed in terminally differentiated cells, such as cardiomyocytes and skeletal muscle cells. Its expression and activity are tightly controlled by a complicated system consisting of transcription factor (TF), non-coding RNA (ncRNA), and post-translational modification (PTM). ARC dysregulation has been shown to be closely associated with many chronic diseases, including cardiovascular disease, cancer, diabetes, and neurodegenerative disease. However, the detailed mechanisms of ARC involved in the progression of these diseases remain unclear to a large extent. In this review, we mainly focus on the regulatory mechanisms of ARC expression and activity and its role in PCD. We also discuss the underlying mechanisms of ARC in health and disease and highlight the potential implications of ARC in the clinical treatment of patients with chronic diseases. This information may assist in developing ARC-based therapeutic strategies for patients with chronic diseases and expand researchers' understanding of ARC.

The interregulatory circuit between non-coding RNA and apoptotic signaling in diabetic cardiomyopathy

Diabetes mellitus has surged in prevalence, emerging as a prominent epidemic and assuming a foremost position among prevalent medical disorders. Diabetes constitutes a pivotal risk element for cardiovascular maladies, with diabetic cardiomyopathy (DCM) standing out as a substantial complication encountered by individuals with diabetes. Apoptosis represents a physiological phenomenon observed throughout the aging and developmental stages, giving rise to the programmed cell death, which is implicated in DCM. Non-coding RNAs assume significant functions in modulation of gene expression. Their deviant expression of ncRNAs is implicated in overseeing diverse cellular attributes such as proliferation, apoptosis, and has been postulated to play a role in the progression of DCM. Notably, ncRNAs and the process of apoptosis can mutually influence and cooperate in shaping the destiny of human cardiac tissues. Therefore, the exploration of the interplay between apoptosis and non-coding RNAs holds paramount importance in the formulation of efficacious therapeutic and preventive approaches for managing DCM. In this review, we provide a comprehensive overview of the apoptotic signaling pathways relevant to DCM and subsequently delve into the reciprocal regulation between apoptosis and ncRNAs in DCM. These insights contribute to an enhanced comprehension of DCM and the development of therapeutic strategies.

MicroRNAs in diabetic macroangiopathy

Diabetic macroangiopathy is a leading cause of diabetes-related mortality worldwide. Both genetic and environmental factors, through a multitude of underlying molecular mechanisms, contribute to the pathogenesis of diabetic macroangiopathy. MicroRNAs (miRNAs), a class of non-coding RNAs known for their functional diversity and expression specificity, are increasingly recognized for their roles in the initiation and progression of diabetes and diabetic macroangiopathy. In this review, we will describe the biogenesis of miRNAs, and summarize their functions in diabetic macroangiopathy, including atherosclerosis, peripheral artery disease, coronary artery disease, and cerebrovascular disease, which are anticipated to provide new insights into future perspectives of miRNAs in basic, translational and clinical research, ultimately advancing the diagnosis, prevention, and treatment of diabetic macroangiopathy.

Molecular Basis of Cardiomyopathies in Type 2 Diabetes

Diabetic cardiomyopathy (DbCM) is a common complication in individuals with type 2 diabetes mellitus (T2DM), and its exact pathogenesis is still debated. It was hypothesized that chronic hyperglycemia and insulin resistance activate critical cellular pathways that are responsible for numerous functional and anatomical perturbations in the heart. Interstitial inflammation, oxidative stress, myocardial apoptosis, mitochondria dysfunction, defective cardiac metabolism, cardiac remodeling, hypertrophy and fibrosis with consequent impaired contractility are the most common mechanisms implicated. Epigenetic changes also have an emerging role in the regulation of these crucial pathways. The aim of this review was to highlight the increasing knowledge on the molecular mechanisms of DbCM and the new therapies targeting specific pathways.

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.

LncRNA JHDM1D-AS1 promotes osteogenic differentiation of periodontal ligament cells by targeting miR-532-5p to activate IGF1R signaling

OBJECTIVE

The aim of this study was to explore the mechanism underlying periodontal ligament cells (PDLCs) osteogenic differentiation.

BACKGROUND

Periodontitis causes damage to tooth-supporting apparatus and eventually leads to tooth loss. PDLCs hold great promise in periodontal regeneration due to their osteogenic features.

METHODS

The expression of osteogenic markers, lncRNA JHDM1D-AS1, miR-532-5p and IGF1R was examined. For osteogenic differentiation, primary human PDLCs (hPDLCs) were cultured in an osteogenic medium, and it was assessed by ALP activity and Alizarin Red staining. The interaction between JHDM1D-AS1, miR-532-5p and IGF1R was analyzed via dual luciferase, RIP and RNA pull-down assays.

RESULTS

JHDM1D-AS1 was up-regulated during osteogenic differentiation and its silencing inhibited hPDLC osteogenic differentiation. JHDM1D-AS1 worked as a miR-532-5p sponge in hPDLCs. miR-532-5p directly targeted IGF1R to suppress its expression, and miR-532-5p knockdown facilitated osteogenic differentiation of hPDLCs. Overexpression of IGF1R promoted osteogenic differentiation of hPDLCs via activating Notch/HES1 signaling in hPDLCs.

CONCLUSION

JHDM1D-AS1 promotes osteogenic differentiation of hPDLCs via sponging miR-532-5p to facilitate IGF1R expression and activate Notch/HES1 signaling.

Multigenerational genetic effects of paternal cadmium exposure on ovarian granulosa cell apoptosis

To explore whether paternal cadmium (Cd) exposure causes ovarian granulosa cell (GC) apoptosis in offspring and the multigenerational genetic effects. From postnatal day 28 (PND28) until adulthood (PND56), SPF male Sprague-Dawley (SD) rats were gavaged daily with varying concentrations of CdCl_2. (0, 0.5, 2, and 8 mg/kg). After treatment, the F1 generation was produced by mating with untreated female rats, and the F1 generation male rats were mated with untreated female rats to produce the F2 generation. Apoptotic bodies (electron microscopy) and significantly higher apoptotic rates (flow cytometry) were observed in both F1 and F2 ovarian GCs following paternal Cd exposure. Moreover, the mRNA (qRTPCR) or protein (Western blotting) levels of bax, bcl2, bcl-xl, caspase 3, caspase 8, and caspase 9 were changed to varying degrees. Apoptosis-related miRNAs (qRTPCR) and methylation modifications of apoptosis-related genes (bisulfite-sequencing PCR) in ovarian GCs were further detected. Compared with those of controls, the expression patterns of miRNAs in F1 and F2 offspring were different after paternal Cd exposure, while the average methylation level of apoptosis-related genes did not change significantly (except for individual loci). In summary, there are paternal genetic intergenerational and transgenerational effects on ovarian GC apoptosis induced by paternal Cd exposure. These genetic effects were related to the upregulation of BAX, BCL-XL, Cle-CASPASE 3, and Cle-CASPASE 9 in F1 and the upregulation of Cle-CASPASE 3 in F2 progeny. Important changes in apoptosis-related miRNAs were also observed.

Non-neuronal cholinergic system delays cardiac remodelling in type 1 diabetes

Aims

Type 1 diabetes mellitus (T1DM) is associated with increased risk of cardiovascular disease (CVD) and mortality. The underlying mechanisms for T1DM-induced heart disease still remains unclear. In this study, we aimed to investigate the effects of cardiac non-neuronal cholinergic system (cNNCS) activation on T1DM-induced cardiac remodelling.

Methods

T1DM was induced in C57Bl6 mice using low-dose streptozotocin. Western blot analysis was used to measure the expression of cNNCS components at different time points (4, 8, 12, and 16 weeks after T1DM induction). To assess the potential benefits of cNNCS activation, T1DM was induced in mice with cardiomyocyte-specific overexpression of choline acetyltransferase (ChAT), the enzyme required for acetylcholine (Ac) synthesis. We evaluated the effects of ChAT overexpression on cNNCS components, vascular and cardiac remodelling, and cardiac function.

Key findings

Western blot analysis revealed dysregulation of cNNCS components in hearts of T1DM mice. Intracardiac ACh levels were also reduced in T1DM. Activation of ChAT significantly increased intracardiac ACh levels and prevented diabetes-induced dysregulation of cNNCS components. This was associated with preserved microvessel density, reduced apoptosis and fibrosis, and improved cardiac function.

Significance

Our study suggests that cNNCS dysregulation may contribute to T1DM-induced cardiac remodelling, and that increasing ACh levels may be a potential therapeutic strategy to prevent or delay T1DM-induced heart disease.

Investigating microRNAs in diabetic cardiomyopathy as tools for early detection and therapeutics

To profile microRNAs population of glucose-induced cardiomyoblast cell line and identify the differentially expressed microRNAs and their role under pre-diabetes and diabetes condition in vitro. Rat fetal ventricular cardiomyoblast cell line H9c2 was treated with D-glucose to mimic pre-diabetic, diabetic, and high-glucose conditions. Alteration in cellular, nuclear morphology, and change in ROS generation was analyzed through fluorescent staining. Small RNA sequencing was performed using Illumina NextSeq 550 sequencer and was validated using stem-loop qRT-PCR. A large number (~ 100) differential miRNAs were detected in each treated samples as compared to control; however, a similar expression pattern was observed between pre-diabetes and diabetes conditions with the exception for miR-429, miR-101b-5p, miR-503-3p, miR-384-5p, miR-412-5p, miR-672-5p, and miR-532-3p. Functional annotation of differential expressed target genes revealed their involvement in significantly enriched key pathways associated with diabetic cardiomyopathy. For the first time, we report the differential expression of miRNAs (miR-1249, miR-3596d, miR- 3586-3p, miR-7b-3p, miR-191, miR-330-3p, miR-328a, let7i-5p, miR-146-3p, miR-26a-3p) in diabetes-induced cardiac cells. Hyperglycemia threatens the cell homeostasis by dysregulation of miRNAs that begins at a glucose level 10 mM and remains undetected. Analysis of differential expressed miRNAs in pre-diabetes and diabetes conditions and their role in regulatory mechanisms of diabetic cardiomyopathy holds high potential in the direction of using miRNAs as minimally invasive diagnostic and therapeutic tools.

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.

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.

Downregulation of autophagy-related circular RNA (ACR) is correlated with poor survival of patients with chronic heart failure

Autophagy‐related circular RNA (ACR) has been reported to protect myocardial tissues from injury and participate in chronic heart failure (CHF), while its role in CHF is unknown. This study aimed to study the role of ACR in CHF. ACR and miR-532 levels in CHF (ischemic-origin, n = 60) patients and healthy controls (n = 60) were analyzed by RT-qPCR. The prognostic value of ACR was analyzed by survival curve analysis. ACR was overexpressed in cardiomyocytes, and the effects of ACR overexpression on the expression of miR-532 and the methylation of miR-532 gene were analyzed using RT-qPCR and methylation-specific PCR (MSP). Cardiomyocyte apoptosis under hypoxic conditions was analyzed with cell apoptosis assay. It was observed that ACR expression was downregulated in CHF. Kaplan‑Meier and multivariate Cox regression analysis suggested that low ACR predicted overall survival of CHF patients and ACR was inversely correlated with miR-532 across plasma samples. In cardiomyocytes, ACR increased miR-532 gene methylation to decrease its expression. Cell apoptosis analysis showed that ACR overexpression reduced the enhancing effects of miR-532 overexpression on cardiomyocyte apoptosis under hypoxic conditions. Therefore, ACR is downregulated in CHF and may suppress hypoxia-induced cardiomyocytes by downregulating miR-532 via methylation.

Melatonin Inhibits OGD/R-Induced H9c2 Cardiomyocyte Pyroptosis via Regulation of MT2/miR-155/FOXO3a/ARC Axis

Emerging literature suggests that pyroptosis plays a critical role in ischemia/hypoxia (I/R) -induced myocardial injury. Melatonin has been implicated in attenuating I/R-induced injury of cardiomyocytes. Nevertheless, whether melatonin inhibits I/R-induced pyroptosis of cardiomyocytes and the underlying molecular mechanisms remain unexploited.H9c2 cardiomyocytes were cultured under oxygen-glucose deprivation/reperfusion (OGD/R) condition to establish a myocardial pyroptosis model in vitro. OGD/R-induced pyroptosis was evaluated by CCK-8 assay, IL-1β and IL-18 release, and western blotting. Luciferase reporter assay was utilized to validate the association between miR-155 and Forkhead box O3a (FOXO3a).Melatonin could inhibit OGD/R-induced pyroptosis of H9c2 cells and upregulation of FOXO3a contributed to the antipyroptotic effect of melatonin. Melatonin reduced miR-155 expression, which led to FOXO3a upregulation and inhibition of pyroptosis in OGD/R-exposed H9c2 cells. miR-155 inhibitor enhanced the antipyroptotic effect of melatonin in OGD/R-exposed H9c2 cells. Melatonin-induced downregulation of miR-155 and upregulation of FOXO3a were reversed by melatonin receptor 2 (MT2) siRNA. Melatonin treatment also led to an increased level of apoptosis repressor with caspase recruitment domain (ARC), which was inhibited by FOXO3a siRNA. Moreover, silencing ARC by siRNA significantly blocked the antipyroptotic actions of melatonin, whereas ARC overexpression enhanced the antipyroptotic actions of melatonin in OGD/R-exposed H9c2 cells.Our findings demonstrated that melatonin prevented OGD/R-induced pyroptosis via regulating the MT2/miR-155/FOXO3a/ARC axis in cardiomyocytes.

Molecular Mechanisms and Epigenetic Regulation in Diabetic Cardiomyopathy

Diabetes mellitus (DM) is an important lifestyle disease. Type 2 diabetes is one of the prime contributors to cardiovascular diseases (CVD) and diabetic cardiomyopathy (DbCM) and leads to increased morbidity and mortality in patients with DM. DbCM is a typical cardiac disease, characterized by cardiac remodeling in the presence of DM and in the absence of other comorbidities such as hypertension, valvular diseases, and coronary artery disease. DbCM is associated with defective cardiac metabolism, altered mitochondrial structure and function, and other physiological and pathophysiological signaling mechanisms such as oxidative stress, inflammation, myocardial apoptosis, and autophagy. Epigenetic modifiers are crucial players in the pathogenesis of DbCM. Thus, it is important to explore the role of epigenetic modifiers or modifications in regulating molecular pathways associated with DbCM. In this review, we have discussed the role of various epigenetic mechanisms such as histone modifications (acetylation and methylation), DNA methylation and non-coding RNAs in modulating molecular pathways involved in the pathophysiology of the DbCM.

Increased expression of six-large extracellular vesicle-derived miRNAs signature for nonvalvular atrial fibrillation

Backgrounds

Non-valvular atrial fibrillation (AF) is the most common type of cardiac arrhythmia. AF is caused by electrophysiological abnormalities and alteration of atrial tissues, which leads to the generation of abnormal electrical impulses. Extracellular vesicles (EVs) are membrane-bound vesicles released by all cell types. Large EVs (lEVs) are secreted by the outward budding of the plasma membrane during cell activation or cell stress. lEVs are thought to act as vehicles for miRNAs to modulate cardiovascular function, and to be involved in the pathophysiology of cardiovascular diseases (CVDs), including AF. This study identified lEV-miRNAs that were differentially expressed between AF patients and non-AF controls.

Methods

lEVs were isolated by differential centrifugation and characterized by Nanoparticle Tracking Analysis (NTA), Transmission Electron Microscopy (TEM), flow cytometry and Western blot analysis. For the discovery phase, 12 AF patients and 12 non-AF controls were enrolled to determine lEV-miRNA profile using quantitative reverse transcription polymerase chain reaction array. The candidate miRNAs were confirmed their expression in a validation cohort using droplet digital PCR (30 AF, 30 controls). Bioinformatics analysis was used to predict their target genes and functional pathways.

Results

TEM, NTA and flow cytometry demonstrated that lEVs presented as cup shape vesicles with a size ranging from 100 to 1000 nm. AF patients had significantly higher levels of lEVs at the size of 101–200 nm than non-AF controls. Western blot analysis was used to confirm EV markers and showed the high level of cardiomyocyte expression (Caveolin-3) in lEVs from AF patients. Nineteen miRNAs were significantly higher (> twofold, p < 0.05) in AF patients compared to non-AF controls. Six highly expressed miRNAs (miR-106b-3p, miR-590-5p, miR-339-3p, miR-378-3p, miR-328-3p, and miR-532-3p) were selected to confirm their expression. Logistic regression analysis showed that increases in the levels of these 6 highly expressed miRNAs associated with AF. The possible functional roles of these lEV-miRNAs may involve in arrhythmogenesis, cell apoptosis, cell proliferation, oxygen hemostasis, and structural remodeling in AF.

Conclusion

Increased expression of six lEV-miRNAs reflects the pathophysiology of AF that may provide fundamental knowledge to develop the novel biomarkers for diagnosis or monitoring the patients with the high risk of AF.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12967-021-03213-6.

CircRNA ACAP2 Is Overexpressed in Myocardial Infarction and Promotes the Maturation of miR-532 to Induce the Apoptosis of Cardiomyocyte

ABSTRACT

CircRNA ACAP2 and miR-532 both promotes the apoptosis of cardiomyocytes, which contributes to myocardial infarction (MI). Therefore, ACAP2 and miR-532 may interact with each other to participate in MI. Plasma samples from both patients with MI (n = 65) and healthy controls (n = 65) were subjected to RNA extractions and real-time quantitative polymerase chain reaction to analyze the expression of ACAP2, mature miR-532, and premature miR-532. Correlations among them were analyzed by Pearson's correlation coefficient. Expression of both mature miR-532 and premature miR-532 in cardiomyocytes with ACAP2 overexpression was analyzed by real-time quantitative polymerase chain reaction to study the effects of ACAP2 overexpression on the maturation of miR-532. The role of ACAP2 and miR-532 in regulating the apoptosis of cardiomyocytes induced by hypoxia was analyzed by cell apoptosis assay. In this study, we found that ACAP2 and mature miR-532 were both upregulated in plasma from patients with MI. ACAP2 and mature miR-532 were inversely correlated, whereas ACAP2 and premature miR-532 were not significantly correlated. In cardiomyocytes, overexpression of ACAP2 increased the expression of mature miR-532, but not premature miR-532. Cell apoptosis analysis showed that ACAP2 and miR-532 overexpression promoted the apoptosis of cardiomyocytes induced by hypoxia treatment. In addition, miR-532 inhibitor reduced the effects of ACAP2 overexpression. ACAP2 is overexpressed in MI and may promote the maturation of miR-532 to induce the apoptosis of cardiomyocyte.

Diabetes induces dysregulation of microRNAs associated with survival, proliferation and self-renewal in cardiac progenitor cells

AIMS/HYPOTHESIS

Diabetes mellitus causes a progressive loss of functional efficacy in stem cells, including cardiac progenitor cells (CPCs). The underlying molecular mechanism is still not known. MicroRNAs (miRNAs) are small, non-coding RNA molecules that regulate genes at the post-transcriptional level. We aimed to determine if diabetes mellitus induces dysregulation of miRNAs in CPCs and to test if in vitro therapeutic modulation of miRNAs would improve the functions of diabetic CPCs.

METHODS

CPCs were isolated from a mouse model of type 2 diabetes (db/db), non-diabetic mice and human right atrial appendage heart tissue. Total RNA isolated from mouse CPCs was miRNA profiled using Nanostring analysis. Bioinformatic analysis was employed to predict the functional effects of altered miRNAs. MS analysis was applied to determine the targets, which were confirmed by western blot analysis. Finally, to assess the beneficial effects of therapeutic modulation of miRNAs in vitro and in vivo, prosurvival miR-30c-5p was overexpressed in mouse and human diabetic CPCs, and the functional consequences were determined by measuring the level of apoptotic cell death, cardiac function and mitochondrial membrane potential (MMP).

RESULTS

Among 599 miRNAs analysed in mouse CPCs via Nanostring analysis, 16 miRNAs showed significant dysregulation in the diabetic CPCs. Using bioinformatics tools and quantitative real-time PCR (qPCR) validation, four altered miRNAs (miR-30c-5p, miR-329-3p, miR-376c-3p and miR-495-3p) were identified to play an important role in cell proliferation and survival. Diabetes mellitus significantly downregulated miR-30c-5p, while it upregulated miR-329-3p, miR-376c-3p and miR-495-3p. MS analysis revealed proapoptotic voltage-dependent anion-selective channel 1 (VDAC1) as a direct target for miR-30c-5p, and cell cycle regulator, cyclin-dependent protein kinase 6 (CDK6), as the direct target for miR-329-3p, miR-376c-3p and miR-495-3p. Western blot analyses showed a marked increase in VDAC1 expression, while CDK6 expression was downregulated in diabetic CPCs. Finally, in vitro and in vivo overexpression of miR-30c-5p markedly reduced the apoptotic cell death and preserved MMP in diabetic CPCs via inhibition of VDAC1.

CONCLUSIONS/INTERPRETATION

Our results demonstrate that diabetes mellitus induces a marked dysregulation of miRNAs associated with stem cell survival, proliferation and differentiation, and that therapeutic overexpression of prosurvival miR-30c-5p reduced diabetes-induced cell death and loss of MMP in CPCs via the newly identified target for miR-30c-5p, VDAC1.