MicroRNAs in β-cell biology, insulin resistance, diabetes and its complications

miR-4428 and miR-185-5p as Key Modulators of Insulin Sensitivity and Glucose Homeostasis: Insights into Pathways and Therapeutic Potential in Type 2 Diabetes Mellitus

Type 2 Diabetes Mellitus (T2DM) is a chronic metabolic disorder characterized by insulin resistance and dysregulation of glucose metabolism. MicroRNAs (miRNAs) such as miR-4428 and miR-185-5p play critical roles in post-transcriptional regulation of genes involved in these processes, but their specific contributions to T2DM pathogenesis remain unclear. Plasma samples from T2DM patients and non-diabetic controls were analyzed for miR-4428 and miR-185-5p expression using microarray and bioinformatics tools. Target genes were predicted, and pathway enrichment analysis was performed to explore biological roles. Differential expression analysis revealed a 2.3-fold upregulation of miR-4428 and a 14.4-fold downregulation of miR-185-5p in T2DM patients compared to controls. Predicted targets such as ADAR, KLF9, and SOGA1 were linked to glucose metabolism and insulin signaling pathways. Enrichment analysis highlighted associations with neuronal signaling, chromatin remodeling, and metabolic regulation pathways. miR-4428 and miR-185-5p regulate critical insulin sensitivity and glucose metabolism pathways, making them promising biomarkers and therapeutic targets for managing T2DM. Future studies should validate these findings experimentally to advance miRNA-based interventions for T2DM and its complications.

Metabolic Syndrome Indicators and Cardiovascular/Endocrine Risks in Rural Ecuador: A Cross-Sectional Study

Background/Objectives: This study assessed the prevalence of metabolic syndrome (MetS) and its association with cardiovascular and endocrine diseases in a rural Ecuadorian parish population. Methods: This cross-sectional study included 200 participants. Descriptive statistics were computed for glucose, total cholesterol, and triglyceride levels. Logistic regression estimated the odds ratios (ORs) for the likelihood of cardiovascular (hypertension, coronary artery disease, stroke) and endocrine diseases (diabetes and other metabolic disorders) in relation to MetS biomarkers. Results: The study included 200 participants, with average glucose (123.09 mg/dL), cholesterol (229.58 mg/dL), and triglycerides (188.75 mg/dL) levels exceeding standard thresholds. Logistic regression analysis showed that glucose was the strongest predictor, increasing cardiovascular disease odds by 6.9% (OR = 1.069, p < 0.001) and endocrine disease odds by 11.8% (OR = 1.118, p < 0.001) after adjustment. Cholesterol and triglycerides also significantly contributed to the risk of both diseases. The models demonstrated a high predictive performance (AUC: 0.933 for cardiovascular disease and 0.993 for endocrine diseases). Conclusions: MetS was significantly associated with cardiovascular and endocrine disease risks in the rural population. Integrating personalized healthcare, such as tailored dietary counseling, culturally adapted interventions, and mobile health technologies, is crucial for improving the early detection and management of MetS in underserved communities.

Unraveling diabetes complexity through natural products, miRNAs modulation, and future paradigms in precision medicine and global health

BACKGROUND AND AIMS

The challenge posed by diabetes necessitates a paradigm shift from conventional diagnostic approaches focusing on glucose and lipid levels to the transformative realm of precision medicine. This approach, leveraging advancements in genomics and proteomics, acknowledges the individualistic genetic variations, dietary preferences, and environmental exposures in diabetes management. The study comprehensively analyzes the evolving diabetes landscape, emphasizing the pivotal role of genomics, proteomics, microRNAs (miRNAs), metabolomics, and bioinformatics.

RESULTS

Precision medicine revolutionizes diabetes research and treatment by diverging from traditional diagnostic methods, recognizing the heterogeneous nature of the condition. MiRNAs, crucial post-transcriptional gene regulators, emerge as promising therapeutic targets, influencing key facets such as insulin signaling and glucose homeostasis. Metabolomics, an integral component of omics sciences, contributes significantly to diabetes research, elucidating metabolic disruptions, and offering potential biomarkers for early diagnosis and personalized therapies. Bioinformatics unveils dynamic connections between natural substances, miRNAs, and cellular pathways, aiding in the exploration of the intricate molecular terrain in diabetes. The study underscores the imperative for experimental validation in natural product-based diabetes therapy, emphasizing the need for in vitro and in vivo studies leading to clinical trials for assessing effectiveness, safety, and tolerability in real-world applications. Global cooperation and ethical considerations play a pivotal role in addressing diabetes challenges worldwide, necessitating a multifaceted approach that integrates traditional knowledge, cultural competence, and environmental awareness.

CONCLUSIONS

The key components of diabetes treatment, including precision medicine, metabolomics, bioinformatics, and experimental validation, converge in future strategies, embodying a holistic paradigm for diabetes care anchored in cutting-edge research and global healthcare accessibility.

Identifying miRNA Signatures Associated with Pancreatic Islet Dysfunction in a FOXA2-Deficient iPSC Model

The pathogenesis of diabetes involves complex changes in the expression profiles of mRNA and non-coding RNAs within pancreatic islet cells. Recent progress in induced pluripotent stem cell (iPSC) technology have allowed the modeling of diabetes-associated genes. Our recent study using FOXA2-deficient human iPSC models has highlighted an essential role for FOXA2 in the development of human pancreas. Here, we aimed to provide further insights on the role of microRNAs (miRNAs) by studying the miRNA-mRNA regulatory networks in iPSC-derived islets lacking the FOXA2 gene. Consistent with our previous findings, the absence of FOXA2 significantly downregulated the expression of islet hormones, INS, and GCG, alongside other key developmental genes in pancreatic islets. Concordantly, RNA-Seq analysis showed significant downregulation of genes related to pancreatic development and upregulation of genes associated with nervous system development and lipid metabolic pathways. Furthermore, the absence of FOXA2 in iPSC-derived pancreatic islets resulted in significant alterations in miRNA expression, with 61 miRNAs upregulated and 99 downregulated. The upregulated miRNAs targeted crucial genes involved in diabetes and pancreatic islet cell development. In contrary, the absence of FOXA2 in islets showed a network of downregulated miRNAs targeting genes related to nervous system development and lipid metabolism. These findings highlight the impact of FOXA2 absence on pancreatic islet development and suggesting intricate miRNA-mRNA regulatory networks affecting pancreatic islet cell development.

Unraveling the role of microRNAs: potential biomarkers for gestational diabetes mellitus revealed through RNA sequencing analysis

BACKGROUND

Gestational diabetes mellitus (GDM) poses significant health risks for both mothers and children, contributing to long-term complications such as type 2 diabetes and cardiovascular disease. This study explores the potential of microRNAs (miRNAs) as biomarkers for GDM by analyzing peripheral blood samples from GDM patients.

METHOD

Ten samples, including peripheral blood from 5 GDM patients and 5 controls, were collected to perform the RNA sequencing analysis. Differentially expressed miRNAs were further validated by quantitative real-time polymerase chain reaction.

RESULTS

A total of 2287 miRNAs were identified, 229 of which showed differential expression. Validation by qRT-PCR confirmed significant up-regulation of miR-5193, miR-5003-3p, miR-3127-5p, novel-miR-96, miR-6734-5p, and miR-122-5p, while miR-10395-3p was down-regulated. Bioinformatics analyses revealed the involvement of these miRNAs in pathways associated with herpes simplex virus 1 infection.

CONCLUSION

This study provides insights into the differential expression of miRNAs in GDM patients and their potential roles in disease pathogenesis. It suggests that the differentially expressed miRNAs could serve as potential biomarkers for GDM, shedding light on the complex molecular mechanisms involved.

Altered expression of miR-375 and miR-541 in type 2 diabetes patients with and without coronary artery disease (CAD): the potential of miR-375 as a CAD biomarker

Background

MicroRNAs (miRNAs, miRs) have been linked to beta-cell pathologies and have also shown potential as biomarkers for cardiovascular disease. This study aimed to evaluate the expression of miR-375 and miR-541 in T2D patients with and without CAD, in order to determine the potential of these miRNAs as biomarkers for assessing CAD risk.

Methods

This study was conducted on 106 patients with T2D who underwent coronary angiographic examination. Reverse transcription was performed using the cDNA synthesis kit. Real-time PCR was performed using the SYBR Green method and specific primers. The ability to predict which person had developed CAD was evaluated by calculating the area under the receiver-operating characteristic (ROC) curve (AUC).

Results

The expression of miR-375 was significantly higher in samples from CAD patients compared to those without CAD (p = 0.009). While the expression of miR-541 was also higher in CAD patients, the difference was not statistically significant. In terms of predicting CAD, miR-375 was found to be a suitable predictor with an AUC of 0.74 (p = 0.01), while miR-541 was not. With a cut-off value of 0.016 for miR-375, the sensitivity was 67% and the specificity was 80%.

Conclusion

Our results indicated that circulating levels of miR-375 and miR-541 were elevated in T2D patients with CAD compared to those without CAD. This suggests that miR-375 could potentially be used as a non-invasive biomarker for the diagnosis of CAD in T2D patients.

MicroRNAs in chronic pediatric diseases (Review)

MicroRNAs are small non-coding RNAs with a length of 20-24 nucleotides. They bind to the 3'-untranslated region of target genes to induce the degradation of target mRNAs or inhibit their translation. Therefore, they are involved in the regulation of development, apoptosis, proliferation, differentiation and other biological processes (including hormone secretion, signaling and viral infections). Chronic diseases in children may be difficult to treat and are often associated with malnutrition resulting from a poor diet. Consequently, further complications, disease aggravation and increased treatment costs impose a burden on patients and their families. Existing evidence suggests that microRNAs are involved in various chronic non-neoplastic diseases in children. The present review discusses the roles of microRNAs in five major chronic diseases in children, namely, diabetes mellitus, congenital heart diseases, liver diseases, bronchial asthma and epilepsy, providing a theoretical basis for them to become therapeutic biomarkers in chronic pediatric diseases.

Robust nontarget DNA-triggered catalytic hairpin assembly amplification strategy for the improved sensing of microRNA in complex biological matrices

A simple but robust fluorescence strategy based on a nontarget DNA-triggered catalytic hairpin assembly (CHA) was constructed to probe microRNA-21 (miR-21). A short ssDNA rather than degradable target miRNA was employed as an initiator. Two molecular beacons needed to assist the CHA process were simplified to avoid unfavorable nonspecific interactions. In the presence of the target, the initiator was released from a partially duplex and triggered the cyclic CHA reaction, resulting in a significantly amplified optical readout. A wide linear range from 0.1 pM to 1000 pM for the sensing of miR-21 in buffer was achieved with a low detection limit of 0.76 pM. Fortunately, this strategy demonstrated an obviously improved performance for miR-21 detection in diluted serum. The fluorescence signals were enhanced remarkably and the sensitivity was further improved to 0.12 pM in 10% serum. The stability for miR-21 quantification and the capability for the analysis of single nucleotide polymorphisms (SNPs) were also improved greatly. More importantly, the biosensor could be applied to image miR-21 in different living tumor cells with high resolution, illustrating its promising potential for the assay of miRNAs in various complex situations for early-stage disease diagnosis and biological studies in cells.

The role of miRNAs carried by extracellular vesicles in type 2 diabetes and its complications

Diabetes poses severe global public health problems and places heavy burdens on the medical and economic systems of society. Type 2 diabetes (T2D) accounts for 90% of these cases. Diabetes also often accompanies serious complications that threaten multiple organs such as the brain, eyes, kidneys, and the cardiovascular system. MicroRNAs (miRNAs) carried by extracellular vesicles (EV-miRNAs) are considered to mediate cross-organ and cross-cellular communication and have a vital role in the pathophysiology of T2D. They also offer promising sources of diabetes-related biomarkers and serve as effective therapeutic targets. Here, we briefly reviewed studies of EV-miRNAs in T2D and related complications. Specially, we innovatively explore the targeting nature of miRNA action due to the target specificity of vesicle binding, aiding mechanism understanding as well as the detection and treatment of diseases.

Text mining-based identification of promising miRNA biomarkers for diabetes mellitus

Introduction

MicroRNAs (miRNAs) are small, non-coding RNAs that play a critical role in diabetes development. While individual studies investigating the mechanisms of miRNA in diabetes provide valuable insights, their narrow focus limits their ability to provide a comprehensive understanding of miRNAs' role in diabetes pathogenesis and complications.

Methods

To reduce potential bias from individual studies, we employed a text mining-based approach to identify the role of miRNAs in diabetes and their potential as biomarker candidates. Abstracts of publications were tokenized, and biomedical terms were extracted for topic modeling. Four machine learning algorithms, including Naïve Bayes, Decision Tree, Random Forest, and Support Vector Machines (SVM), were employed for diabetes classification. Feature importance was assessed to construct miRNA-diabetes networks.

Results

Our analysis identified 13 distinct topics of miRNA studies in the context of diabetes, and miRNAs exhibited a topic-specific pattern. SVM achieved a promising prediction for diabetes with an accuracy score greater than 60%. Notably, miR-146 emerged as one of the critical biomarkers for diabetes prediction, targeting multiple genes and signal pathways implicated in diabetic inflammation and neuropathy.

Conclusion

This comprehensive approach yields generalizable insights into the network miRNAs-diabetes network and supports miRNAs' potential as a biomarker for diabetes.

A Postmortem Case Study-An Analysis of microRNA Patterns in a Korean Native Male Calf (Bos taurus coreanae) That Died of Fat Necrosis

Korean native cattle are highly valued for their rich marbling and flavor. Nonetheless, endeavors to enhance marbling levels can result in obesity, a prevalent contributor to fat necrosis. Fat necrosis is characterized by the formation of necrotic fat masses in the abdominal cavity, which physically puts pressure on affected organs, causing physical torsion or obstruction, resulting in death and consequent economic loss. Pancreatic injuries or diabetes mellitus were reported as factors of fat necrosis in humans; however, the pathogenesis in animals has not been established. In this study, we identified fat necrosis in a 6-month-old Korean native cow and investigated its potential underlying causes. Serum samples were utilized for a microarray analysis of bovine miRNA. Comparative examination of miRNA expression levels between cattle afflicted with fat necrosis and healthy cattle unveiled notable variances in 24 miRNAs, such as bta-miR-26a, bta-miR-29a, bta-miR-30a-5p and bta-miR-181a. Upon conducting miRNA-mediated KEGG pathway analysis, several pathways including the prolactin signal pathway, insulin resistance, autophagy, the insulin-signaling pathway and the FoxO-signaling pathway were found to be significantly enriched in the calf affected by fat necrosis. As a result, this study potentially indicates a potential connection between fat necrosis and diabetes in Korean native cattle.

Circulating miRNA expression in long-standing type 1 diabetes mellitus

Type 1 diabetes is a chronic autoimmune disease which results in inefficient regulation of glucose homeostasis and can lead to different vascular comorbidities through life. In this study we aimed to analyse the circulating miRNA expression profile of patients with type 1 diabetes, and with no other associated pathology. For this, fasting plasma was obtained from 85 subjects. Next generation sequencing analysis was firstly performed to identify miRNAs that were differentially expressed between groups (20 patients vs. 10 controls). hsa-miR-1-3p, hsa-miR-200b-3p, hsa-miR-9-5p, and hsa-miR-1200 expression was also measured by Taqman RT-PCR to validate the observed changes (34 patients vs. 21 controls). Finally, through a bioinformatic approach, the main pathways affected by the target genes of these miRNAs were studied. Among the studied miRNAs, hsa-miR-1-3p expression was found significantly increased in patients with type 1 diabetes compared to controls, and positively correlated with glycated haemoglobin levels. Additionally, by using a bioinformatic approach, we could observe that changes in hsa-miR-1-3p directly affect genes involved in vascular development and cardiovascular pathologies. Our results suggest that, circulating hsa-miR-1-3p in plasma, together with glycaemic control, could be used as prognostic biomarkers in type 1 diabetes, helping to prevent the development of vascular complications in these patients.

Consequences of the exposome to gestational diabetes mellitus

The exposome is the cumulative measure of environmental influences and associated biological responses throughout the lifespan, including those from the environment, diet, behaviour, and endogenous processes. The exposome concept and the 2030 Agenda for the Sustainable Development Goals (SDGs) from the United Nations are the basis for understanding the aetiology and consequences of non-communicable diseases, including gestational diabetes mellitus (GDM). Pregnancy may be developed in an environment with adverse factors part of the immediate internal medium for fetus development and the external medium to which the pregnant woman is exposed. The placenta is the interface between maternal and fetal compartments and acts as a protective barrier or easing agent to transfer exposome from mother to fetus. Under and over-nutrition in utero, exposure to adverse environmental pollutants such as heavy metals, endocrine-disrupting chemicals, pesticides, drugs, pharmaceuticals, lifestyle, air pollutants, and tobacco smoke plays a determinant role in the development of GDM. This phenomenon is worsened by metabolic stress postnatally, such as obesity which increases the risk of GDM and other diseases. Clinical risk factors for GDM development include its aetiology. It is proposed that knowledge-based interventions to change the potential interdependent ecto-exposome and endo-exposome could avoid the occurrence and consequences of GDM.

Circulatory microRNAs in helminthiases: Potent as diagnostics biomarker, its potential role and limitations

Infections caused by helminths are responsible for severe public health problems and economic burden on continental scale. Well-timed and precise diagnosis of helminth infections is critical for taking by appropriate approaches for pathogen control. Circulating miRNAs are stable diagnostic tool for different diseases found in a variety of body fluid. As diagnostic biomarkers in infectious diseases, miRNAs detection in body fluids of helminth infected hosts is growing promptly. Uncovering miRNAs is a relatively new tool, used for early-stage detection of helminth infection from experimental or non-invasive clinical samples. miRNAs can be detected in body fluids such as serum, saliva, urine, and tissues of helminth infected host, mainly blood offering important benefits for diagnosis accurately. In this review, we discuss different characteristics of helminth parasite-derived circulating and EV miRNAs, supporting its potential uses in for helminth diagnosis and treatment efficiency.

The UCA1 and microRNA-18a signaling pathway mediates the irisin-lowering effect of metformin in the management of polycystic ovary syndrome

INTRODUCTION

The present study aimed to clarify the underlying mechanism of metformin (met) in the management of polycystic ovary syndrome (PCOS) and to explore the role of the UCA1/microRNA-18a signaling pathway in the control of PCOS.

MATERIAL AND METHODS

Real-time PCR was performed to compare the levels of irisin, blood glucose, UCA1 and miR-18a among PCOS, PCOS + Met, and control groups using area under curve (AUC) values. In-silicon analysis and luciferase assay were performed to explore the regulatory relationship among UCA1, miR-18a and irisin. Real-time PCR and Western blot analysis were carried out to detect the effect of met on the expression of UCA1, miR-18a and irisin.

RESULTS

AUC of UCA1 was the highest while AUC of irisin was the lowest. Also, irisin and UCA1 levels in the PCOS group were much higher than those in the PCOS + Met group, while miR-18a level in the PCOS group was much lower than in the PCOS + Met group. Through the luciferase assay, miR-18a was proved to directly bind to the irisin 3'UTR. Additionally, irisin was identified to be a target gene of miR-18a. Finally, treatment with met at an increasing concentration reduced the level of UCA1 and irisin but increased the level of miR-18a in a dose-dependent manner.

CONCLUSIONS

In the management of PCOS, the irisin-lowering effect of met is regulated by the UCA1/miR-18a/RhoB signaling pathway.

Correlation of Impaired NF-kB Activation in Sepsis-Induced Acute Lung Injury (ALI) in Diabetic Rats

Background

The allergic lung inflammation is reduced in the diabetic rats which can be restored by treating it with insulin. As observed in multiple studies, the diabetic patients are more vulnerable to infections and their inflammatory reactions. There are confirmations on insulin and its effects control the inflammatory reactions.

Objective

This study was performed to understand the correlation of impaired NF-kB activation in sepsis-induced acute lung injury (ALI) in diabetic rats. Material and Methods. Streptozotocin was used for induction of diabetes and sepsis was induced by colon ligation puncture surgery. Post 6 hours of CLP, the lungs in the groups were analyzed for cell infiltration using broncho-alveolar lavage. The lungs were removed for histopathological analysis at the end of study where the bronchioles, alveoli, and edema were analyzed and compared. Cell expressions quantified by the help of antibodies and inflammatory events were analyzed.

Results

Diabetic rats developed mild acute lung injury due to the suppression of activation of NF-kB in alveolar macrophages.

Conclusion

Even the diabetic rats were more susceptible to sepsis in comparison to the nondiabetic rats, but the NF-kB suppression has a major role to play in the faint symptoms of ALI.

Mitochondrial Antioxidant SkQ1 Has a Beneficial Effect in Experimental Diabetes as Based on the Analysis of Expression of microRNAs and mRNAs for the Oxidative Metabolism Regulators

Diabetes mellitus and related complications are among the most important problems of the world-leading healthcare systems. Despite their priority, molecular and genetic aspects of diabetes pathogenesis are poorly understood; however, the involvement of oxidative stress in this process is undoubted. Rats with experimental diabetes induced by the intraperitoneal injection of alloxan were subjected to the antioxidant pre-therapy with a series of mitochondria-targeted 10-(6’-plastoquinonyl)decyltriphenylphosphonium (SkQ1) injections and analyzed for the expression of mRNAs and microRNAs by real-time quantitative polymerase chain reaction to identify potential predictors of diabetes. Animals that received SkQ1 before diabetes induction demonstrated lower blood glucose levels compared to the diabetic animals not subjected to the therapy. SkQ1 caused changes in the mRNA levels of genes involved in the cellular defense against free radicals, which indicates a beneficial effect of the pre-therapy. Moreover, similar changes were observed on the epigenetic level, as the microRNA expression patterns not only proved the SkQ1 efficacy but also correlated with the expression levels of their mRNA targets. Oxidative stress and macromolecule damage by free radicals are determining factors in diabetes, which suggests that strategies aimed at restoring the antioxidant status of the cell can be beneficial. Mitochondria-targeted antioxidant SkQ1 demonstrates positive effects on several levels, from the normalization of the blood glucose content to genetic and epigenetic changes. Our results can serve as a basis for the development of novel therapeutic and diagnostic strategies.

Molecular Aspects of Lifestyle and Environmental Effects in Patients With Diabetes: JACC Focus Seminar

Diabetes is characterized as an integrated condition of dysregulated metabolism across multiple tissues, with well-established consequences on the cardiovascular system. Recent advances in precision phenotyping in biofluids and tissues in large human observational and interventional studies have afforded a unique opportunity to translate seminal findings in models and cellular systems to patients at risk for diabetes and its complications. Specifically, techniques to assay metabolites, proteins, and transcripts, alongside more recent assessment of the gut microbiome, underscore the complexity of diabetes in patients, suggesting avenues for precision phenotyping of risk, response to intervention, and potentially novel therapies. In addition, the influence of external factors and inputs (eg, activity, diet, medical therapies) on each domain of molecular characterization has gained prominence toward better understanding their role in prevention. Here, the authors provide a broad overview of the role of several of these molecular domains in human translational investigation in diabetes.

MicroRNA-185-5p inhibits hepatic gluconeogenesis and reduces fasting blood glucose levels by suppressing G6Pase

Aims/hypothesis: MicroRNAs (miRNAs) are known to contribute to many metabolic diseases, including type 2 diabetes. This study aimed to investigate the roles and molecular mechanisms of miR-185-5p in the regulation of hepatic gluconeogenesis. Methods: MicroRNA high-throughput sequencing was performed to identify differentially expressed miRNAs. High-fat diet-induced obese C57BL/6 mice and db/db mice, a genetic mouse model for diabetes, were used for examining the regulation of hepatic gluconeogenesis. Quantitative reverse transcriptase PCR and Western blotting were performed to measure the expression levels of various genes and proteins. Luciferase reporter assays were used to determine the regulatory roles of miR-185-5p on G6Pase expression. Results: Hepatic miR-185-5p expression was significantly decreased during fasting or insulin resistance. Locked nucleic acid (LNA)-mediated suppression of miR-185-5p increased blood glucose and hepatic gluconeogenesis in healthy mice. In contrast, overexpression of miR-185-5p in db/db mice alleviated blood hyperglycemia and decreased gluconeogenesis. At the molecular level, miR-185-5p directly inhibited G6Pase expression by targeting its 3'-untranslated regions. Furthermore, metformin, an anti-diabetic drug, could upregulate miR-185-5p expression to suppress G6Pase, leading to hepatic gluconeogenesis inhibition. Conclusions/interpretation: Our findings provided a novel insight into the role of miR-185-5p that suppressed hepatic gluconeogenesis and alleviated hyperglycemia by targeting G6Pase. We further identified that the /G6Pase axis mediated the inhibitory effect of metformin on hepatic gluconeogenesis. Thus, miR-185-5p might be a therapeutic target for hepatic glucose overproduction and fasting hyperglycemia.

Circulating microRNA-122, microRNA-126-3p and microRNA-146a are associated with inflammation in patients with pre-diabetes and type 2 diabetes mellitus: A case control study

The prevalence of type 2 diabetes mellitus (T2DM) is increasing dramatically worldwide. Dysregulation of microRNA (miRNA) as key regulators of gene expression, has been reported in numerous diseases including diabetes. The aim of this study was to investigate the expression levels of miRNA-122, miRNA-126-3p and miRNA-146a in diabetic and pre-diabetic patients and in healthy individuals, and to determine whether the changes in the level of these miRNAs are reliable biomarkers in diagnosis, prognosis, and pathogenesis of T2DM. Additionally, we examined the relationship between miRNA levels and plasma concentrations of inflammatory factors including tumor necrosis factor alpha (TNF-α) and interleukin 6 (Il-6) as well as insulin resistance. In this case-control study, participants (n = 90) were allocated to three groups (n = 30/group): T2DM, pre-diabetes and healthy individuals as control (males and females, age: 25–65, body mass index: 25–35). Expression of miRNA was determined by real-time polymerase chain reaction (RT-PCR). Furthermore, plasma concentrations of TNF-α, IL-6 and fasting insulin were measured by enzyme-linked immunosorbent assay. Homeostatic model assessment for insulin resistance (HOMA-IR) was calculated as an indicator of insulin resistance. MiRNA-122 levels were higher while miRNA-126-3p and miRNA-146a levels were lower in T2DM and pre-diabetic patients compared to control (p<0.05). Furthermore, a positive correlation was found between miRNA-122 expression and TNF-α (r = 0.82), IL-6 (r = 0.83) and insulin resistance (r = 0.8). Conversely, negative correlations were observed between miRNA-126-3p and miRNA-146a levels and TNF-α (r = -0.7 and r = -0.82 respectively), IL-6 (r = -0.65 and r = -0.78 respectively) as well as insulin resistance (r = -0.67 and r = -0.78 respectively) (all p<0.05). Findings of this study suggest the miRNAs can potentially contribute to the pathogenesis of T2DM. Further studies are required to examine the reproducibility of these findings.

Diabetes and Cardiovascular Risk in Renal Transplant Patients

End-stage kidney disease (ESKD) is a main public health problem, the prevalence of which is continuously increasing worldwide. Due to adverse effects of renal replacement therapies, kidney transplantation seems to be the optimal form of therapy with significantly improved survival, quality of life and diminished overall costs compared with dialysis. However, post-transplant patients frequently suffer from post-transplant diabetes mellitus (PTDM) which an important risk factor for cardiovascular and cardiovascular-related deaths after transplantation. The management of post-transplant diabetes resembles that of diabetes in the general population as it is based on strict glycemic control as well as screening and treatment of common complications. Lifestyle interventions accompanied by the tailoring of immunosuppressive regimen may be of key importance to mitigate PTDM-associated complications in kidney transplant patients. More transplant-specific approach can include the exchange of tacrolimus with an alternative immunosuppressant (cyclosporine or mammalian target of rapamycin (mTOR) inhibitor), the decrease or cessation of corticosteroid therapy and caution in the prescribing of diuretics since they are independently connected with post-transplant diabetes. Early identification of high-risk patients for cardiovascular diseases enables timely introduction of appropriate therapeutic strategy and results in higher survival rates for patients with a transplanted kidney.

Human Glucagon Expression Is under the Control of miR-320a

Increased glucagon is a hallmark of diabetes and leads to worsening of the hyperglycemia, but the molecular mechanisms causing it are still unknown. We therefore investigated the possibility that microRNAs might be involved in the regulation of glucagon. Indeed, analysis of the glucagon 3' untranslated region (UTR) revealed potential binding sites for miR-320a, and using luciferase reporter assays we found that miR-320a directly targets the 3' UTRs of human and rodent glucagon. In addition, endogenous glucagon mRNA and protein expression as well as glucagon secretion were reduced in response to miR-320a overexpression, whereas inhibition of miR-320a upregulated glucagon expression. Interestingly, miR-320a expression was decreased by high glucose, and this was associated with an increase in glucagon expression in human islets and mouse αTC1-6 cells. Moreover, miR-320a overexpression completely blunted these effects. Importantly, miR-320a was also significantly downregulated in human islets of subjects with type 2 diabetes and this was accompanied by increased glucagon expression. Thus, our data suggest that glucose-induced downregulation of miR-320a may contribute to the paradoxical increase in glucagon observed in type 2 diabetes and reveal for the first time that glucagon expression is under the control by a microRNA providing novel insight into the abnormal regulation of glucagon in diabetes.

Epigenetic Marks in Polycystic Ovary Syndrome

Polycystic Ovary Syndrome (PCOS) is a common endocrine and metabolic disorder that affects women in their reproductive age. Recent studies have shown that genes have an important role in the etiology of PCOS. However, the precise way in which these genes are transcriptionally and post-transcriptionally regulated is poorly understood. The aim of the present review is to provide updated information on miRNAs and DNA methylation as epigenetic marks of PCOS. The data presented here allow concluding that both microRNAs and DNA methylation can be considered as possible useful biomarkers when choosing the treatment for a specific PCOS phenotype and thus represent two important tools for the diagnosis and treatment of PCOS patients.

Loss of miR-23b/27b/24-1 Cluster Impairs Glucose Tolerance via Glycolysis Pathway in Mice

Alterations in miRNAs are associated with many metabolic disorders, such as type 2 diabetes (T2DM). The miR-23b/27b/24-1 cluster contains miR-23b, miR-27b, and miR-24-1, which are located within 881 bp on chromosome 9. Studies examining the roles of miR-23b, miR-27b, and miR-24-1 have demonstrated their multifaceted functions in variable metabolic disorders. However, their joint roles in metabolism in vivo remain elusive. To investigate this subject, we constructed miR-23b/27b/24-1 cluster knockout (KO) mice. Compared with wild-type (WT) mice, the KO mice exhibited impaired glucose tolerance, which was accompanied by a reduction in the respiratory exchange rate (RER). These alterations were more noticeable after a high-fat diet (HFD) induction. Hepatic metabolomic results showed decreased expression of reduced nicotinamide adenine dinucleotide (NADH), nicotinamide adenine dinucleotide (NAD), phosphoenolpyruvic acid (PEP), and phosphoric acid, which are involved in the glycolysis pathway. The transcriptomic results indicated that genes involved in glycolysis showed a downregulation trend. qPCR and Western blot revealed that pyruvate kinase (PKLR), the key rate-limiting enzyme in glycolysis, was significantly reduced after the deletion of the miR-23b/27b/24-1 cluster. Together, these observations suggest that the miR-23b/27b/24-1 cluster is involved in the regulation of glucose homeostasis via the glycolysis pathway.

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.

Blocking exosomal miRNA-153-3p derived from bone marrow mesenchymal stem cells ameliorates hypoxia-induced myocardial and microvascular damage by targeting the ANGPT1-mediated VEGF/PI3k/Akt/eNOS pathway

It has been widely reported that exosomes derived from mesenchymal stem cells (MSCs) have a protective effect on myocardial infarction (MI). However, the specific molecules which play a damaging role in MSCs shuttled miRNAs are much less explored. MiRNA-153-3p (miR-153-3p) is a vital miRNA which has been proved to modulate cell proliferation, apoptosis, angiogenesis, peritoneal fibrosis and aortic calcification. Here, we aim to study the effect and mechanism of miR-153-3p in MSC-derived exosomes on hypoxia-induced myocardial and microvascular damage. The exosomes of MSCs were isolated and identified, and the MSCs-exosomes with low expression of miR-153-3p (exo-miR-153-3p^-) were constructed to interfere with the endothelial cells and cardiomyocytes in the oxygen-glucose deprivation (OGD) model. The viability, apoptosis, angiogenesis of endothelial cells and cardiomyocytes were determined. Additionally, ANGPT1/VEGF/VEGFR2/PI3K/Akt/eNOS pathway was detected by ELISA and/or western blot. The results illustrated that exo-miR-153-3p^- significantly reduced the apoptosis of endothelial cells and cardiomyocytes and promoted their viability. Meanwhile, exo-miR-153-3p^- can promote the angiogenesis of endothelial cells. Mechanistically, miR-153-3p regulates the VEGF/VEGFR2/PI3K/Akt/eNOS pathways by targeting ANGPT1. Intervention with VEGFR2 inhibitor (SU1498, 1 μM) remarkably reversed the protective effect of exo-miR-153-3p^- in vascular endothelial cells and cardiomyocytes treated by OGD. Collectively, MSCs-derived exosomes with low-expressed miR-153-3p notably promotes the activation of ANGPT1 and the VEGF/VEGFR2 /PI3K/Akt/eNOS pathways, thereby preventing the damages endothelial cells and cardiomyocytes against hypoxia.

Gene-Environmental Interplay in Bisphenol A Subchronic Animal Exposure: New Insights into the Epigenetic Regulation of Pancreatic Islets

Endocrine-disrupting chemicals (EDCs) such as bisphenol A (BPA), which is widely used in the plastic industry, have recently been considered to be involved in the pathogenesis of metabolic disorders, including obesity and diabetes. The present study aimed to examine the potentially detrimental effects of BPA on glucose and energy metabolism at the epigenetic level. The blood glucose profile of Wistar rats receiving different oral doses of BPA over 28 days was assessed. At the end of the treatment, the islets of Langerhans were isolated and purified, and their RNA content was extracted. MicroRNA (miRNA) profiling was evaluated using the next generation sequencing (NGS) method. After performing bioinformatic analysis of the NGS data, the gene ontology and data enrichment in terms of significantly disturbed miRNAs were evaluated through different databases, including Enrichr and DIANA tools. Additionally, the DNA methylation and the level of expression of two critical genes in glucose metabolism (PPARγ, Pdx1) were assessed. Subchronic BPA exposure (406 mg/kg/day) disturbed the blood glucose profile (fasting blood glucose and oral glucose tolerance) of Wistar rats and resulted in considerable cytotoxicity. NGS data analyses revealed that the expression of some crucial miRNAs involved in β-cell metabolism and diabetes occurrence and development, including miR-375, miR-676, miR-126-a, and miR-340-5p, was significantly disrupted. According to the DNA methylation evaluation, both PPARγ and Pdx1 genes underwent changes in the methylation level at particular loci on the gene's promoter. The expression levels of these genes were upregulated and downregulated, respectively. Overall, subchronic BPA exposure could cause epigenetic dysregulation at the gene level and interfere with the expression of key miRNAs and the methylation process of genes involved in glucose homeostasis. Understanding the exact underlying mechanisms by which BPA and other EDCs induce endocrine disturbance could be of great importance in the way of finding new preventive and therapeutic approaches.

Effects of quercetin-conjugated with superparamagnetic iron oxide nanoparticles on learning and memory improvement through targeting microRNAs/NF-κB pathway

Quercetin-conjugated superparamagnetic iron oxide nanoparticles (QCSPIONs) have an ameliorative effect on diabetes-induced memory impairment. The current study aimed to compare the effect of quercetin (QC) and QCSPIONs on inflammation-related microRNAs and NF-κB signaling pathways in the hippocampus of diabetic rats. The expression levels of miR-146a, miR-9, NF-κB, and NF-κB-related downstream genes, including TNF-α, BACE1, AβPP, Bax, and Bcl-2 were measured using quantitative real-time PCR. To determine the NF-κB activity, immunohistochemical expression of NF-κB/p65 phosphorylation was employed. Computer simulated docking analysis also performed to find the QC target proteins involved in the NF-κB pathway. Results indicate that diabetes significantly upregulated the expression levels of miR-146a, miR-9, TNF-α, NF-κB, and subsequently AβPP, BACE1, and Bax. Expression analysis shows that QCSPIONs are more effective than pure QC in reducing the expression of miR-9. Interestingly, QCSPIONs reduce the pathological activity of NF-κB and subsequently normalize BACE1, AβPP, and the ratio of Bax/Bcl-2 expression better than pure QC. Comparative docking analyses also show the stronger binding affinity of QC to IKK and BACE1 proteins compared to specific inhibitors of each protein. In conclusion, our study suggests the potent efficacy of QCSPIONs as a promising drug delivery system in memory improvement through targeting the NF-κB pathway.

Role of miRNAs in the pathogenesis of T2DM, insulin secretion, insulin resistance, and β cell dysfunction: the story so far

Diabetes, the most common endocrine disorder, also known as a silent killer disease, is characterized by uncontrolled hyperglycemia. According to the International Diabetes Federation, there were 451 million people with diabetes mellitus worldwide in 2017. It is a multifactorial syndrome caused by genetic as well as environmental factors. Noncoding RNAs, especially the miRNAs, play a significant role in the development as well as the progression of the disease. This is on account of insulin resistance or defects in β cell function. Various miRNAs including miR-7, miR-9, miR-16, miR-27, miR-24, miR-29, miR-124a, miR-135, miR-130a, miR-144, miR-181a, and miR-375 and many more have been associated with insulin resistance and other pathogenic conditions leading to the development of the disease. These miRNAs play significant roles in various pathways underlying insulin resistance such as PI3K, AKT/GSK, and mTOR. The main target genes of these miRNAs are FOXO1, FOXA2, STAT3, and PTEN. The miRNAs carry out important functions in insulin target tissues like the adipose tissue, liver, and muscle. MiRNAs miR-9, miR-375, and miR-124a, are also associated with the secretion of insulin from pancreatic cells. There is an interplay between the miRNAs and pancreatic cell growth, especially the miRNAs affecting development and proliferation of these cells. Most of the miRNAs target more than one gene which not only justifies their use as biomarkers but also their therapeutic potential. The current review has been compiled with an aim to discuss the role of various miRNAs involved in various pathogenic mechanisms including insulin resistance, insulin secretion, and the β cell dysfunction.

Circulating and Adipose Tissue miRNAs in Women With Polycystic Ovary Syndrome and Responses to High-Intensity Interval Training

MicroRNAs (miRNAs) are small non-coding RNAs that regulate gene expression post-transcriptionally. In women with polycystic ovary syndrome (PCOS), several miRNAs are differentially expressed compared to women without PCOS, suggesting a role for miRNAs in PCOS pathophysiology. Exercise training modulates miRNA abundance and is primary lifestyle intervention for women with PCOS. Accordingly, we measured the expression of eight circulating miRNAs selected a priori along with miRNA expression from gluteal and abdominal adipose tissue (AT) in 12 women with PCOS and 12 women matched for age and body mass index without PCOS. We also determined the miRNA expression “signatures” before and after high-intensity interval training (HIT) in 42 women with PCOS randomized to either: (1) low-volume HIT (LV-HIT, 10 × 1 min work bouts at maximal, sustainable intensity, n = 13); (2) high-volume HIT (HV-HIT, 4 × 4 min work bouts reaching 90–95% of maximal heart rate, n = 14); or (3) non-exercise control (Non-Ex, n = 15). Both HIT groups trained three times/week for 16 weeks. miRNAs were extracted from plasma, gluteal and abdominal AT, and quantified via a customized plate array containing eight miRNAs associated with PCOS and/or exercise training responses. Basal expression of circulating miRNA-27b (c-miR-27b), implicated in fatty acid metabolism, adipocyte differentiation and inflammation, was 1.8-fold higher in women with compared to without PCOS (P = 0.006) despite no difference in gluteal or abdominal AT miR-27b expression. Only the HV-HIT protocol increased peak oxygen uptake (VO₂peak L/min; 9%, P = 0.008). There were no changes in body composition. In LV-HIT, but not HV-HIT, the expression of c-miR-27b decreased (0.5-fold, P = 0.007). None of the remaining seven circulating miRNAs changed in LV-HIT, nor was the expression of gluteal or abdominal AT miRNAs altered. Despite increased cardiorespiratory fitness, HV-HIT did not alter the expression of any circulating, gluteal or abdominal AT miRNAs. We conclude that women with PCOS have a higher basal expression of c-miR-27b compared to women without PCOS and that 16 weeks of LV-HIT reduces the expression of this miRNA in women with PCOS. Intense exercise training had little effect on the abundance of the selected miRNAs within subcutaneous AT depots in women with PCOS.

Blood-based analysis of 84 microRNAs identifies molecules deregulated in individuals with type-2 diabetes, risk factors for the disease or metabolic syndrome

AIM

Micro-RNAs (miRNAs) are implicated in insulin-signaling and the development of type-2 diabetes (T2D). Their deregulated expression is mostly described in the pancreas, liver, skeletal muscle, or adipose tissue of diabetic animals. Relevant studies in humans are limited due to difficulties in accessing tissue-biopsies. Though, circulating miRNAs are indicators of organ-specific pathophysiological events and could potentially serve as disease biomarkers. We explored the profile of 84 T2D-related miRNAs in peripheral blood of subjects with or without the disease.

METHODS

An RT-qPCR array screening 84 T2D-related miRNAs was applied in samples of T2D (n = 6) versus non-T2D (n = 6) subjects. The deregulated miRNAs were thereafter analyzed in peripheral blood samples of a validation cohort of 40 T2D and 37 non-T2D individuals [16 controls and 21 subjects with metabolic syndrome (Met-S) and/or T2D risk factors (T2D-RF)], using specific RT-qPCR assays. Correlations with clinicopathological parameters and risk factors were evaluated.

RESULTS

Subjects with the disease displayed decreased levels of miR-214-3p, miR-24-3p and let-7f-5p, compared to those without. MiRNA levels correlated with serum insulin and HbA1c levels in individuals with T2D or Met-S/T2D-RF, and with higher BMI, dyslipidemia and family history in controls.

CONCLUSIONS

Blood levels of miR-214-3p, miR-24-3p and let-7f-5p are down-regulated in T2D- and Met-S/T2D-RF subjects. Future studies are needed to evaluate their potential as disease biomarkers and elucidate the associated tissue-specific pathogenetic mechanisms.

Descending Expression of miR320 in Insulin-Resistant Adipocytes Treated with Ascending Concentrations of Metformin

Some miRNAs are supposed to play a role in insulin resistance and metabolic disorders. Such miRNAs can be differentially expressed in response to a pharmacologic intervention for insulin resistance as a biomarker/risk factor for insulin resistance. This study aimed at determining the effect of Metformin on miR320 expression in insulin-resistant (IR) adipocytes. The 3T3L1 cells were expanded in DMEM, differentiated into adipocytes by differentiating medium, became resistant to insulin, and then were treated with ascending concentrations of Metformin. Quantitative real-time PCR was performed to profile the miR320 expression in 3T3L1 adipocytes, IR adipocytes, and Metformin-treated IR adipocytes. Compared to the normal adipocytes, IR adipocytes exhibited a significantly higher level of miR320 expression, however, in response to Metformin graded concentrations, IR adipocytes down-regulated miR320 and were almost at normal level. The maximum effect of Metformin was at 10 mM. In IR adipocytes, miR320 expression is over-expressed which can be down-regulated by Metformin treatment. The findings provide some information on a potentially new marker to determine insulin resistance and to predict response to insulin resistance therapy.

The Role of Overexpressed Apolipoprotein AV in Insulin-Resistant Hepatocytes

In this paper, we sought to explore the relationship between apolipoprotein AV (APOAV) overexpression and insulin resistance in hepatocytes. The insulin-resistant HepG2 cell model was constructed, and then, APOAV-overexpressed HepG2 cells (B-M) were induced by infecting with a recombinant adenovirus vector. Microarray data were developed from B-M samples compared with negative controls (A-con), and the microarray data were analyzed by bioinformatic methods. APOAV-overexpression induced 313 upregulated genes and 563 downregulated ones in B-M sample. The differentially expressed genes (DEGs) were significantly classified in fat digestion and absorption pathway. Protein-protein interaction network was constructed, and AGTR1 (angiotensin II receptor type 1) and P2RY2 (purinergic receptor P2Y, G-protein coupled 2) were found to be the significant nodes closely related with G-protein related signaling. Additionally, overexpression of APOAV could change the expression of Glut4 and release the insulin resistance of hepatic cells. Thus, APOAV overexpression may prevent the insulin resistance in liver cells by mediating the genes such as AGTR1 and P2RY2.

miRNA Dysregulation in the Development of Non-Alcoholic Fatty Liver Disease and the Related Disorders Type 2 Diabetes Mellitus and Cardiovascular Disease

According to the World Health Organization, the continuing surge in obesity pandemic creates a substantial increase in incidences of metabolic disorders, such as non-alcoholic fatty liver disease (NAFLD), type 2 diabetes mellitus, and cardiovascular disease. MicroRNAs (miRNAs) belong to an evolutionarily conserved class of short (20-22 nucleotides in length) and single-stranded non-coding RNAs. In mammals, miRNAs function as critical post-transcriptional negative regulators involved not only in many biological processes but also in the development of many diseases such as NAFLD and comorbidities. More recently, it has been described that cells can secrete miRNAs in extracellular vesicles, transported by body fluids, and uptaken by other tissues regulating gene expression. Therefore, this could be a mechanism of signaling involved not only in physiological pathways but also in the development of diseases. The association of some miRNA expression profiles with certain disorders has made them very interesting molecules for diagnosis, prognosis, and disease management. The finding of specific miRNA signatures to diagnose NAFLD and related diseases could anticipate the risk of development of related complications and, actually, it is the driving force of present health strategies worldwide. In this review, we have included latest advances in knowledge about the miRNAs involved in the development of NAFLD and related diseases and examined how this knowledge could be used to identify new non-invasive biomarkers and new pharmacological interventions.

Decreased expression of microRNAs targeting type-2 diabetes susceptibility genes in peripheral blood of patients and predisposed individuals

AIM

Certain microRNA molecules (miRNAs) that target genes involved in beta-cell growth and insulin resistance are found deregulated in patients with type-2 diabetes mellitus (T2D) and correlate with its complications. However, the expression profile of miRNAs that regulate genes bearing T2D-related single-nucleotide polymorphisms has been hardly studied. We recently reported that the mRNA patterns of specific T2D-susceptibility genes are impaired in patients, and associate with disease parameters and risk factors. The aim of this study was to explore the levels of miRNAs that target those genes, in peripheral blood of patients versus controls.

METHODS

A panel of 14 miRNAs validated to target the CDKN2A, CDK5, IGF2BP2, KCNQ1, and TSPAN8 genes, was developed upon combined search throughout the DIANNA TarBase v7.0, miRTarBase, miRSearch v3.0-Exiqon, miRGator v3.0, and miRTarget Link Human algorithms. Specifically developed poly(A)polyadenylation(PAP)-reverse transcription(RT)-qPCR protocols were applied in peripheral blood RNA samples from patients and controls. Possible correlations with the disease, clinicopathological parameters and/or risk factors were evaluated.

RESULTS

T2D patients expressed decreased levels of let-7b-5p, miR-1-3p, miR-24-3p, miR-34a-5p, miR-98-5p, and miR-133a-3p, compared with controls. Moreover, these levels correlated with certain disease features including insulin and % HbA1c levels in patients, as well as BMI, triglycerides' levels and family history in controls.

CONCLUSIONS

A T2D-specific expression profile of miRNAs that target disease-susceptibility genes is for the first time described. Future studies are needed to elucidate the associated transcription-regulatory mechanisms, perchance involved in T2D pathogenesis, and to evaluate the potential of these molecules as possible biomarkers for this disorder.

Circulatory miR-98-5p levels are deregulated during diabetes and it inhibits proliferation and promotes apoptosis by targeting PPP1R15B in keratinocytes

Although deregulated circulatory miRNA signatures during diabetes have been identified for some years now, the effects of such miRNAs on several target tissues are not yet thoroughly investigated. The skin that is nourished by components present in the circulation exhibits several notable abnormal features during diabetes. We, therefore, hypothesized that such altered circulatory miRNA levels might be critical in the onset and progression of impaired skin health during diabetes. RNA sequencing from blood samples of normal and type 2 diabetic human subjects identified 9 upregulated and 19 downregulated miRNAs. miR-98-5p was significantly downregulated and its overexpression down-regulated PPP1R15B levels in HaCaT cells and this was prevented by the miR-98-5p inhibitor. This was validated in human primary epidermal keratinocytes and further supported by a dual reporter luciferase assay of the PPP1R15B 3'UTR where miR-98-5p significantly decreased the luciferase activity which was prevented in the presence of the miRNA inhibitor and by mutation in the miRNA binding site. By targeting PPP1R15B, miR-98-5p increases levels of p-eIF2α, BiP and CHOP. Consequently, there was induction of apoptosis accompanied with decreased proliferation in the presence of miR-98-5p. Conversely, miR-98-5p inhibition alone inhibited apoptosis and promoted proliferation. Taken together, our data suggest that by targeting PPP1R15B, miR-98-5p induces apoptosis and decreases proliferation. As opposed to this since circulatory miR-98-5p levels are decreased in diabetes, we believe that this decrease in the circulation that feeds the skin layers might be a major contributor of hyperproliferation as seen in the skin during diabetes.Abbreviations: miRNAs: MicroRNAs; PPP1R15B: PPP1R15B: Protein Phosphatase 1 Regulatory Subunit 15B; TGFβR1: Transforming Growth Factor Beta Receptor 1; ER: Endoplasmic Reticulum; Bip: Binding Immunoglobulin Protein; Chop: CCAAT-enhancer-binding protein homologous protein; p-eIF2α: Eukaryotic Translation Initiation Factor 2a; Bax: Bcl2-associated X protein; Bcl-2: B-cell CLL/lymphoma 2; PCNA: Proliferating Cell Nuclear Antigen; K5: Cytokeratin 5; qRT-PCR: Quantitative Real-Time PCR; ESCC: Oesophageal squamous cell carcinoma; HCC: Hepatocellular carcinoma; CTHRC1: Collagen triple helix repeat containing 1; SALL4: Sal-like protein 4; TNFα: Tumour Necrosis Factor alpha; PGC-1β: Peroxisome Profilerator-activated receptor-γ coactivator-1β; IGF2BP1: Insulin-like growth factor 2 mRNA binding protein 1.

The association of two common polymorphisms in miRNAs with diabetes mellitus: A meta-analysis

BACKGROUND

MicroRNAs (miRNAs) are small noncoding single-stranded RNAs with a length of ∼21 nucleotides. Single nucleotide polymorphisms (SNPs) may affect the function of miRNAs, resulting in a variety of disorders in vivo. Recently, diabetes mellitus (DM) has become a global healthcare problem, and several studies have reported that 2 common polymorphisms (miRNA 146a rs2910164 and miRNA 27a rs895819) are related to susceptibility to diabetes. Given that no consensus had been reached regarding the association of the 2 polymorphisms with diabetes, we conducted this meta-analysis.

METHODS

Four databases (PubMed, EMBASE, Cochrane, and Web of Science) were searched up to January 9, 2019. Pooled odds ratios (ORs) and 95% confidence intervals (CIs) were calculated to evaluate the association strength. Subgroup and sensitivity analyses were also performed.

RESULTS

Six studies involving 2585 cases and 2435 controls for miR146a rs2910164 and 5 studies involving 2922 cases and 2781 controls for miR27a rs895819 were ultimately analyzed in our meta-analysis. Based on pooled results, no statistical significance in association between rs2910164 and diabetes in Caucasians, Asians, or type 2 diabetes was observed in any genetic models. Nevertheless, we found a significant correlation between miRNA27a rs895819 and diabetes in the homozygote model (CC vs TT: OR = 0.58, 95%CI [0.35,0.98]) and recessive model (CC vs CT + TT: OR = 0.59, 95%CI [0.36,0.97]). By performing subgroup analysis, we also observed that C allele conveyed a significant protective effect against diabetes development in Caucasians (C vs T: OR = 0.67, 95%CI [0.52,0.85]).

CONCLUSION

In conclusion, this meta-analysis indicated that miRNA27a rs895819 might play a protective role in diabetes, and miRNA146a rs2910164 likely had no association with diabetes.

Association of single nucleotide polymorphisms of miRNAs involved in the GLUT4 pathway in T2DM in a Chinese population

Background

The insulin/insulin receptor substrate (IRS)/phosphatidylinositol 3‐kinase (PI3K)/protein kinase B (Akt)/GLUT4 pathway plays a crucial role in insulin resistance and is closely associated with T2DM. Accumulating evidence indicates that miRNAs (such as miR‐135a, let‐7d, miR‐107, miR‐96, miR‐29a, miR‐23a, miR‐126, miR‐133a, and miR‐106b) influence the GLUT4 pathway.

Methods

A total of 784 subjects with T2DM and 846 nondiabetic subjects were enrolled and 12 single nucleotide polymorphisms (SNPs) in miRNAs (rs10459194 in miR‐135a‐2, rs10993081 and rs7045890 in let‐7d, rs2296616 in miR‐107, rs2402959 and rs6965643 in miR‐96, rs24168 in miR‐29a, rs3745453 in miR‐23a, rs4636297 in miR‐126, rs8089787 and rs9948906 in miR‐133a‐1 and rs999885 in miR‐106b) involved in the GLUT4 pathway were genotyped using the MassArray method in a Chinese population.

Results

Our data showed that the A allele of rs2402959 in miR‐96 may increase the risk of developing T2DM (p = .002, OR = 1.266; 95% CI: 1.089–1.471). The genotypes of rs3745453 in miR‐23a showed the difference between T2DM and control groups (p < .001). Moreover, for rs2402959, compared with the A/A genotype, the (G/A–G/G) genotype shows a protective effect in T2DM (p = .001, OR = 0.71; 95% CI: 0.58–0.87). For rs3745453, compared with the (A/A–A/G) genotype, the G/G genotype increases the risk of T2DM (p < .001, OR = 1.95; 95% CI: 1.38–2.77). In addition, we also found that rs4636297G/G genotype was associated with lower TC in T2DM group.

Conclusion

Our results revealed that genetic variations in the miRNAs involved in the GLUT4 pathway were associated with T2DM susceptibility in a Chinese population, and these results emphasize the need to study the functional effects of these variations in the miRNAs involved in the GLUT4 pathway on the risk of developing T2DM.

Hepatic miR-181b-5p Contributes to Glycogen Synthesis Through Targeting EGR1

BACKGROUND/AIM

The miR-181 family plays an important role in the regulation of various cellular functions. However, whether miR-181b-5p mediates hepatic insulin resistance remains unknown. In this study, we investigated the effect of miR-181b-5p on the regulation of hepatic glycogen synthesis.

METHODS

The miR-181b-5p levels in the livers of diabetic mice were detected by real-time PCR. The glycogen levels and AKT/GSK pathway activation were examined in human hepatic L02 cells and HepG2 cells transfected with miR-181b-5p mimic or inhibitor. The potential target genes of miR-181b-5p were evaluated using a luciferase reporter assay and Western blot analysis. EGR1-specific siRNA and pCMV-EGR1 were used to further determine the role of miR-181b-5p in hepatic glycogen synthesis in vitro. Hepatic inhibition of miR-181b-5p in mice was performed using adeno-associated virus 8 (AAV8) vectors by tail intravenous injection.

RESULTS

The miR-181b-5p levels were significantly decreased in the serum and livers of diabetic mice as well as the serum of type 2 diabetes patients. Importantly, inhibition of miR-181b-5p expression impaired the AKT/GSK pathway and reduced glycogenesis in hepatocytes. Moreover, upregulation of miR-181b-5p reversed high-glucose-induced suppression of glycogenesis. Further analysis revealed that early growth response 1 (EGR1) was a downstream target of miR-181b-5p. Silencing of EGR1 expression rescued miR-181b-5p inhibition-reduced AKT/GSK pathway activation and glycogenesis in hepatocytes. Hepatic inhibition of miR-181b-5p led to insulin resistance in C57BL/6 J mice.

CONCLUSION

We demonstrated that miR-181b-5p contributes to glycogen synthesis by targeting EGR1, thereby regulating PTEN expression to mediate hepatic insulin resistance.

A therapeutic approach towards microRNA29 family in vascular diabetic complications: A boon or curse?

Diabetes Mellitus (DM) is one of the major metabolic disorders and its severity leads to death. Enhancement in hyperglycaemic conditions of DM gives rise to endothelial impairment in small and large blood vessels contributing towards microvascular and macrovascular complications respectively. The pathogenesis of diabetic complications is associated with interruption of various signal transduction pathways due to epigenetic modifications such as aberrant histone modifications, DNA methylation and expression of miRNAs along with the long non-coding RNAs (lncRNAs). Amongst these epigenetic alterations, modulated expressions of miRNAs confer to apoptosis and endothelial dysfunction of organs that gives rise to vascular complications. In this review, we principally focussed on physiological role of miR29 family in DM and have discussed crosstalk between miR29 family and numerous genes involved in signal transduction pathways of Diabetic vascular complications. Incidences of diabetic retinopathy exploiting the role of miR29 in regulation of EMT process, differential expression patterns of miR29 and promising therapeutic role of miR29 have been discussed. We have summarised the therapeutic role of miR29 in podocyte impairment and how miR29 regulates the expressions of profibrotic, inflammatory and ECM encoding genes in renal fibrosis under diabetic conditions. We have also highlighted impact of miR29 expression patterns in cardiac angiopathy, cardiomyocyte's apoptosis and cardiac fibrosis. Additionally, we have also presented the contradictory actions of miR29 family in amelioration as well as in enhancement of diabetic complications.

Association of miRNA - 320 expression level and its target gene endothelin-1 with the susceptibility and clinical features of polycystic ovary syndrome

Background

Polycystic ovary syndrome (PCOS) is a common reproductive endocrine disorder characterized by obesity, hyperandrogenism, and insulin resistance (IR). MicroRNAs (miRNAs) are small noncoding RNA associated with ovarian follicle development and female fertility. The objective of this study was to investigate the role of miRNA- 320 and its target gene endothelin-1 (ET-1) as a noninvasive biomarker of PCOS and to evaluate its possible relationship with IR as well as clinic-morphological features of PCOS.

Methods

Case-control study enrolled 60 patients with PCOS and 40 control group. We subdivided our PCOS women according to homeostasis model assessments of insulin resistance (HOMA-IR) to PCOS women with and without IR.ET-1 levels were measured by ELISA. We estimated the serum expression level of miRNA- 320 by real-time polymerase chain reaction.

Results

Our results revealed that serum miR-320 expression level was lower in PCOS patients compared to controls, in particular, PCOS women with IR. Moreover, it was negatively correlated to its target gene; ET-I as well as fasting serum insulin (FSI), HOMA-IR, PCOS phenotype; hirsutism score, ovarian volume and antral follicle count (AFC). In the PCOS group, linear regression analysis revealed that only hirsutism and HOMA-IR was the main predictor of expression levels of miRNA − 320 among other clinical and laboratory biomarkers of PCOS. The sensitivity and specificity of serum miR-320 expression levels in diagnosis PCOS was 80, and 97.5% respectively.

Conclusion

The Expression serum levels of miR-320 were lower in PCOS compared to control and it could be a noninvasive diagnostic biomarker of PCOS.

Differential expression of candidate circulating microRNAs in maternal blood leukocytes of the patients with preeclampsia and gestational diabetes mellitus

OBJECTIVES

Preeclampsia (PE) is diagnosed in women presenting with new onset hypertension accompanied by proteinuria. Gestational diabetes mellitus (GDM) is the carbohydrate intolerance that can occur in pregnancy. Neutrophil activation is related to PE and GDM. Circulating microRNAs (miRs) are small, noncoding RNA molecules. The aim of this study was to verify the expression levels of three candidate miRs in blood leukocytes of the patients with PE, GDM, and PE-GDM compared to healthy controls.

STUDY DESIGN

We selected miR-21-3p, miR-155-5p, and miR-16-5p which have been associated with GDM and PE. Using real-time quantitative PCR, the expression levels of miR-21-3p, miR-155-5p, miR-16-5p were analyzed in PE (n = 23), GDM (n = 19), PE, and GDM (n = 9) compared to healthy controls (n = 28).

MAIN OUTCOME MEASURES

The relative expression of the target miR in patient samples was compared to the calibrator and the results were expressed as relative quantification values.

RESULTS

There was a significant decrease in the expression levels of miR-21-3p in GDM and PE and miR-155-5p in PE group. No significant differences were observed in the expression levels of miRs in PE-GDM group. On receiving operator characteristic (ROC) analysis, areas under the curve (AUC) of the expression ratio of miR-21-3p in GDM was 0.73, and miR-21-3p, miR-155-5p in PE were 0.69 and 0.81, respectively.

CONCLUSIONS

Our findings indicated that decreased miR-21-3p and miR-155-5p expression levels are associated with PE and miR-21-3p levels are associated with GDM. Our study for the first time revealed that miR-21-3p, miR-16-5p and miR155-5p are not related to PE-GDM group.

RFSMMA: A New Computational Model to Identify and Prioritize Potential Small Molecule-MiRNA Associations

More and more studies found that many complex human diseases occur accompanied by aberrant expression of microRNAs (miRNAs). Small molecule (SM) drugs have been utilized to treat complex human diseases by affecting the expression of miRNAs. Several computational methods were proposed to infer underlying associations between SMs and miRNAs. In our study, we proposed a new calculation model of random forest based small molecule-miRNA association prediction (RFSMMA) which was based on the known SM-miRNA associations in the SM2miR database. RFSMMA utilized the similarity of SMs and miRNAs as features to represent SM-miRNA pairs and further implemented the machine learning algorithm of random forest to train training samples and obtain a prediction model. In RFSMMA, integrating multiple kinds of similarity can avoid the bias of single similarity and choosing more reliable features from original features can represent SM-miRNA pairs more accurately. We carried out cross validations to assess predictive accuracy of RFSMMA. As a result, RFSMMA acquired AUCs of 0.9854, 0.9839, 0.7052, and 0.9917 ± 0.0008 under global leave-one-out cross validation (LOOCV), miRNA-fixed local LOOCV, SM-fixed local LOOCV, and 5-fold cross validation, respectively, under data set 1. Based on data set 2, RFSMMA obtained AUCs of 0.8456, 0.8463, 0.6653, and 0.8389 ± 0.0033 under four cross validations according to the order mentioned above. In addition, we implemented a case study on three common SMs, namely, 5-fluorouracil, 17β-estradiol, and 5-aza-2'-deoxycytidine. Among the top 50 associated miRNAs of these three SMs predicted by RFSMMA, 31, 32, and 28 miRNAs were verified, respectively. Therefore, RFSMMA is shown to be an effective and reliable tool for identifying underlying SM-miRNA associations.

Blood-based analysis of type-2 diabetes mellitus susceptibility genes identifies specific transcript variants with deregulated expression and association with disease risk

Despite significant progress by genome-wide association studies, the ability of genetic variants to conduce to the prediction or prognosis of type-2 diabetes (T2D) is weak. Expression analysis of the corresponding genes may suggest possible links between single-nucleotide polymorphisms and T2D phenotype and/or risk. Herein, we investigated the expression patterns of 24 T2D-susceptibility genes, and their individual transcript variants (tv), in peripheral blood of T2D patients and controls (CTs), applying RNA-seq and real-time qPCR methodologies, and explore possible associations with disease features. Our data revealed the deregulation of certain transcripts in T2D patients. Among them, the down-regulation of CAPN10 tv3 was confirmed as an independent predictor for T2D. In patients, increased expression of CDK5 tv2, CDKN2A tv3 or THADA tv5 correlated positively with serum insulin levels, of CDK5 tv1 positively with % HbA1c levels, while in controls, elevated levels of TSPAN8 were associated positively with the presence of T2D family history. Herein, a T2D-specific expression profile of specific transcripts of disease-susceptibility genes is for the first time described in human peripheral blood. Large-scale studies are needed to evaluate the potential of these molecules to serve as disease biomarkers.