A plasma circulating miRNAs profile predicts type 2 diabetes mellitus and prediabetes: from the CORDIOPREV study

Evaluation of circulating plasma miR-9, miR-29a, miR-192, and miR-375 as potential biomarkers for predicting prediabetes and type 2 diabetes in Nepali adult population

Circulating plasma miRNAs have emerged as potential early predictors of glucometabolic disorders. However, their biomarker potential remains unvalidated in populations with diverse genetic backgrounds, races, and ethnicities. This study aims to validate the biomarker potential of plasma miR-9, miR-29a, miR-192, and miR-375 for early detection of prediabetes and type 2 diabetes mellitus (T2DM) in Nepali populations that represent distinct genetic backgrounds, races, and ethnicities. A total of 46 adults, categorized into healthy controls (n = 25), prediabetes (n = 9), and T2DM (n = 12) groups, were enrolled. Baseline sociodemographic, anthropometric, and clinical characteristics were collected. Fold change in plasma expression of all four miRNAs was quantified using RT-qPCR against the RNU6B reference gene. Their biomarker potential was determined by receiver operating characteristic (ROC) curve analysis. Multivariate discriminant function and hierarchical cluster analyses were used to evaluate the effectiveness of the miRNA panel in reclassifying study participants who were initially categorized according to their glucose tolerance status. Plasma expression of all four miRNAs was significantly upregulated in T2DM patients compared to normoglycemic controls. Furthermore, the expression of only miR-29a and miR-375 was upregulated in T2DM patients than in prediabetic individuals. Notably, only miR-192 expression was significantly upregulated in prediabetic individuals than in the normoglycemic controls. The miRNA expression profiles had the potential of reclassifying the participants into three original groups with an accuracy of 69.6 %. ROC curve analysis identified miR-192 as the predictor for both prediabetes and T2DM, while miR-9, miR-29a, miR-192, and miR-375 were predictive only for T2DM. The specific set of miRNA combinations significantly improved their predictive accuracy. This study validates the early predictive biomarker potential of plasma miR-9, miR-29a, miR-192, and miR-375 also in the Nepali population and paves the way for future translational studies to validate their utility in clinical laboratories.

Dietary modulation of microRNAs in insulin resistance and type 2 diabetes

The prevalence of type 2 diabetes is increasing worldwide. Various molecular mechanisms have been proposed to interfere with the insulin signaling pathway. Recent advances in proteomics and genomics indicate that one such mechanism involves the post-transcriptional regulation of insulin signaling by microRNA (miRNA). These noncoding RNAs typically induce messenger RNA (mRNA) degradation or translational repression by interacting with the 3' untranslated region (3'UTR) of target mRNA. Dietary components and patterns, which can either enhance or impair the insulin signaling pathway, have been found to regulate miRNA expression in both in vitro and in vivo studies. This review provides an overview of the current knowledge of how dietary components influence the expression of miRNAs related to the control of the insulin signaling pathway and discusses the potential application of these findings in precision nutrition.

Effects of Phytochemicals on Type 2 Diabetes via MicroRNAs

PURPOSE OF REVIEW

Type 2 diabetes, characterized by inadequate insulin secretion and resistance, is increasingly prevalent. To effectively manage type 2 diabetes, identifying new therapeutic targets is crucial. MicroRNAs, short noncoding RNA molecules, play a pivotal role in regulating β-cell function, insulin production, and resistance, and show promise as biomarkers for predicting type 2 diabetes onset. Phytochemicals, known for their antioxidant activities, may influence microRNA expression, potentially improving insulin sensitivity and mitigating associated complications. This review aims to explore the significance of microRNA in type 2 diabetes, their potential as biomarkers, and how certain phytochemicals may modulate microRNA expressions to reduce or prevent diabetes and its complications.

RECENT FINDINGS

Current research suggests that microRNAs show promise as novel therapeutic biomarkers for diagnosing type 2 diabetes and monitoring diabetic complications. Additionally, phytochemicals may regulate microRNAs to control type 2 diabetes, presenting a potential therapeutic strategy. The multifactorial effects of phytochemicals on type 2 diabetes and its complications through microRNAs warrant further research to elucidate their mechanisms. Comprehensive clinical trials are needed to assess the safety and efficacy of phytochemicals and their combinations. Given their ability to modulate microRNAs expression, incorporating phytochemical-rich foods into the diet may be beneficial.

Investigating the altered expression of miR-486-5p and miR-novel-chr1_40444 in dysglycemia in a South African population

AIMS

This study aims to investigate miR-486-5p and miR-novel-chr1_40444 expressions in dysglycemic individuals. Validating RNA-sequencing findings in a larger sample via reverse transcription qPCR (RT-qPCR), we aim to address global diagnostic and screening limitations, using an African cohort as an example.

MATERIALS AND METHODS

This cross-sectional study involved 1,271 individuals [normoglycemic (n = 974), prediabetic (n = 206), screen-detected type 2 diabetes (n = 91)] from the ongoing Vascular and Metabolic Health (VMH) study in Cape Town, South Africa. Whole blood miRNA expression was assessed using TaqMan-based RT-qPCR, with data normalized to an endogenous control (miR-16-5p).

RESULTS

Significant underexpression was observed in prediabetes vs normoglycemia for miR-486-5p (P = 0.038), whilst both miRNAs demonstrated significant upregulation in screen-detected type 2 diabetes vs normoglycemia (miR-486-5p, P = 0.009; miR-novel-chr1_40444, P < 0.001), and screen-detected type 2 diabetes in comparison with prediabetes (miR-486-5p, P < 0.001; miR-novel-chr1_40444, P < 0.001). Multivariable regression analyses revealed pronounced interrelations between miR-novel-chr1_40444 and screen-detected type 2 diabetes in unadjusted and adjusted models (Model 1: P < 0.001, Model 2: P < 0.001, Model 3: P = 0.030). Moreover, receiver operating characteristic (ROC) curves revealed significantly enhanced diagnostic capabilities for screen-detected type 2 diabetes vs either normoglycemia (AUC = 0.971, P < 0.001), non-diabetes (AUC = 0.959, P < 0.001), or prediabetes (AUC = 0.902, P < 0.001) when combining the miRNAs with 2 h postprandial glucose.

CONCLUSIONS

This study demonstrated the enhanced power of incorporating miRNAs with traditional markers in distinguishing screen-detected type 2 diabetes, warranting further investigations on their unique role in the development of type 2 diabetes.

Liver microRNA transcriptome reveals miR-182 as link between type 2 diabetes and fatty liver disease in obesity

Background

The development of obesity-associated comorbidities such as type 2 diabetes (T2D) and hepatic steatosis has been linked to selected microRNAs in individual studies; however, an unbiased genome-wide approach to map T2D induced changes in the miRNAs landscape in human liver samples, and a subsequent robust identification and validation of target genes are still missing.

Methods

Liver biopsies from age- and gender-matched obese individuals with (n=20) or without (n=20) T2D were used for microRNA microarray analysis. The candidate microRNA and target genes were validated in 85 human liver samples, and subsequently mechanistically characterized in hepatic cells as well as by dietary interventions and hepatic overexpression in mice.

Results

Here, we present the human hepatic microRNA transcriptome of type 2 diabetes in liver biopsies and use a novel seed prediction tool to robustly identify microRNA target genes, which were then validated in a unique cohort of 85 human livers. Subsequent mouse studies identified a distinct signature of T2D-associated miRNAs, partly conserved in both species. Of those, human-murine miR-182-5 p was the most associated with whole-body glucose homeostasis and hepatic lipid metabolism. Its target gene LRP6 was consistently lower expressed in livers of obese T2D humans and mice as well as under conditions of miR-182-5 p overexpression. Weight loss in obese mice decreased hepatic miR-182-5 p and restored Lrp6 expression and other miR-182-5 p target genes. Hepatic overexpression of miR-182-5 p in mice rapidly decreased LRP6 protein levels and increased liver triglycerides and fasting insulin under obesogenic conditions after only seven days.

Conclusions

By mapping the hepatic miRNA-transcriptome of type 2 diabetic obese subjects, validating conserved miRNAs in diet-induced mice, and establishing a novel miRNA prediction tool, we provide a robust and unique resource that will pave the way for future studies in the field. As proof of concept, we revealed that the repression of LRP6 by miR-182-5 p, which promotes lipogenesis and impairs glucose homeostasis, provides a novel mechanistic link between T2D and non-alcoholic fatty liver disease, and demonstrate in vivo that miR-182-5 p can serve as a future drug target for the treatment of obesity-driven hepatic steatosis.

Funding

This work was supported by research funding from the Deutsche Forschungsgemeinschaft (KI 1887/2-1, KI 1887/2-2, KI 1887/3-1 and CRC-TR296), the European Research Council (ERC, CoG Yoyo LepReSens no. 101002247; PTP), the Helmholtz Association (Initiative and Networking Fund International Helmholtz Research School for Diabetes; MB) and the German Center for Diabetes Research (DZD Next Grant 82DZD09D1G).

Analysis of Circulating miRNA Expression Profiles in Type 2 Diabetes Patients with Diabetic Foot Complications

Type 2 diabetes mellitus (T2DM) is associated with various complications, including diabetic foot, which can lead to significant morbidity and mortality. Non-healing foot ulcers in diabetic patients are a major risk factor for infections and amputations. Despite conventional treatments, which have limited efficacy, there is a need for more effective therapies. MicroRNAs (miRs) are small non-coding RNAs that play a role in gene expression and have been implicated in diabetic wound healing. miR expression was analyzed through RT-qPCR in 41 diabetic foot Mexican patients and 50 controls. Diabetic foot patients showed significant increases in plasma levels of miR-17-5p (p = 0.001), miR-191-5p (p = 0.001), let-7e-5p (p = 0.001), and miR-33a-5p (p = 0.005) when compared to controls. Elevated levels of miR-17, miR-191, and miR-121 correlated with higher glucose levels in patients with diabetic foot ulcers (r = 0.30, p = 0.004; r = 0.25, p = 0.01; and r = 0.21, p = 0.05, respectively). Levels of miR-17 showed the highest diagnostic potential (AUC 0.903, p = 0.0001). These findings underscore the possible role of these miRs in developing diabetes complications. Our study suggests that high miR-17, miR-191, and miR-121 expression is strongly associated with higher glucose levels and the development of diabetic foot ulcers.

Dysregulated microRNAs in type 2 diabetes and breast cancer: Potential associated molecular mechanisms

Type 2 diabetes (T2D) is a multifaceted and heterogeneous syndrome associated with complications such as hypertension, coronary artery disease, and notably, breast cancer (BC). The connection between T2D and BC is established through processes that involve insulin resistance, inflammation and other factors. Despite this comprehension the specific cellular and molecular mechanisms linking T2D to BC, especially through microRNAs (miRNAs), remain elusive. miRNAs are regulators of gene expression at the post-transcriptional level and have the function of regulating target genes by modulating various signaling pathways and biological processes. However, the signaling pathways and biological processes regulated by miRNAs that are associated with T2D and BC have not yet been elucidated. This review aims to identify dysregulated miRNAs in both T2D and BC, exploring potential signaling pathways and biological processes that collectively contribute to the development of BC.

Oxidative Stress, Endothelial Dysfunction, and N-Acetylcysteine in Type 2 Diabetes Mellitus

Significance: Cardiovascular diseases (CVDs) remain the leading cause of morbidity and mortality globally. Endothelial dysfunction is closely associated with the development and progression of CVDs. Patients with diabetes mellitus (DM) especially type 2 DM (T2DM) exhibit a significant endothelial cell (EC) dysfunction with substantially increased risk for CVDs. Recent Advances: Excessive reactive oxygen species (ROS) and oxidative stress are important contributing factors to EC dysfunction and subsequent CVDs. ROS production is significantly increased in DM and is critically involved in the development of endothelial dysfunction in diabetic patients. In this review, efforts are made to discuss the role of excessive ROS and oxidative stress in the pathogenesis of endothelial dysfunction and the mechanisms for excessive ROS production and oxidative stress in T2DM. Critical Issues: Although studies with diabetic animal models have shown that targeting ROS with traditional antioxidant vitamins C and E or other antioxidant supplements provides promising beneficial effects on endothelial function, the cardiovascular outcomes of clinical studies with these antioxidant supplements have been inconsistent in diabetic patients. Future Directions: Preclinical and limited clinical data suggest that N-acetylcysteine (NAC) treatment may improve endothelial function in diabetic patients. However, well-designed clinical studies are needed to determine if NAC supplementation would effectively preserve endothelial function and improve the clinical outcomes of diabetic patients with reduced cardiovascular morbidity and mortality. With better understanding on the mechanisms of ROS generation and ROS-mediated endothelial damages/dysfunction, it is anticipated that new selective ROS-modulating agents and effective personalized strategies will be developed for the management of endothelial dysfunction in DM.

CAPN2 correlates with insulin resistance states in PCOS as evidenced by multi-dataset analysis

OBJECTIVE

IR emerges as a feature in the pathophysiology of PCOS, precipitating ovulatory anomalies and endometrial dysfunctions that contribute to the infertility challenges characteristic of this condition. Despite its clinical significance, a consensus on the precise mechanisms by which IR exacerbates PCOS is still lacking. This study aims to harness bioinformatics tools to unearth key IR-associated genes in PCOS patients, providing a platform for future therapeutic research and potential intervention strategies.

METHODS

We retrieved 4 datasets detailing PCOS from the GEO, and sourced IRGs from the MSigDB. We applied WGCNA to identify gene modules linked to insulin resistance, utilizing IR scores as a phenotypic marker. Gene refinement was executed through the LASSO, SVM, and Boruta feature selection algorithms. qPCR was carried out on selected samples to confirm findings. We predicted both miRNA and lncRNA targets using the ENCORI database, which facilitated the construction of a ceRNA network. Lastly, a drug-target network was derived from the CTD.

RESULTS

Thirteen genes related to insulin resistance in PCOS were identified via WGCNA analysis. LASSO, SVM, and Boruta algorithms further isolated CAPN2 as a notably upregulated gene, corroborated by biological verification. The ceRNA network involving lncRNA XIST and hsa-miR-433-3p indicated a possible regulatory link with CAPN2, supported by ENCORI database. Drug prediction analysis uncovered seven pharmacological agents, most being significant regulators of the endocrine system, as potential candidates for addressing insulin resistance in PCOS.

CONCLUSIONS

This study highlights the pivotal role of CAPN2 in insulin resistance within the context of PCOS, emphasizing its importance as both a critical biomarker and a potential therapeutic target. By identifying CAPN2, our research contributes to the expanding evidence surrounding the CAPN family, particularly CAPN10, in insulin resistance studies beyond PCOS. This work enriches our understanding of the mechanisms underlying insulin resistance, offering insights that bridge gaps in the current scientific landscape.

Metabolic memory: mechanisms and diseases

Metabolic diseases and their complications impose health and economic burdens worldwide. Evidence from past experimental studies and clinical trials suggests our body may have the ability to remember the past metabolic environment, such as hyperglycemia or hyperlipidemia, thus leading to chronic inflammatory disorders and other diseases even after the elimination of these metabolic environments. The long-term effects of that aberrant metabolism on the body have been summarized as metabolic memory and are found to assume a crucial role in states of health and disease. Multiple molecular mechanisms collectively participate in metabolic memory management, resulting in different cellular alterations as well as tissue and organ dysfunctions, culminating in disease progression and even affecting offspring. The elucidation and expansion of the concept of metabolic memory provides more comprehensive insight into pathogenic mechanisms underlying metabolic diseases and complications and promises to be a new target in disease detection and management. Here, we retrace the history of relevant research on metabolic memory and summarize its salient characteristics. We provide a detailed discussion of the mechanisms by which metabolic memory may be involved in disease development at molecular, cellular, and organ levels, with emphasis on the impact of epigenetic modulations. Finally, we present some of the pivotal findings arguing in favor of targeting metabolic memory to develop therapeutic strategies for metabolic diseases and provide the latest reflections on the consequences of metabolic memory as well as their implications for human health and diseases.

Association between circulating micro-ribonucleic acids and metabolic syndrome in older adults from a population-based study

BACKGROUND AND AIMS

Aging is a major factor in development of chronic non-communicable diseases (NCD). Epigenetic causes are risk factors in NCD development since studies indicate that the expression of micro-ribonucleic acids (miRs) is altered under different clinical conditions. This study aimed to analyze the expression profile of circulating miRs and investigate their association with biomarkers of cardiometabolic risk in older adults living in São Paulo municipality, Brazil.

METHODS

A cross-sectional study was conducted based on the analysis of data from 200 older adults, with a mean age of 69.1 (0.5) years old participating in the ISA-Nutrition. The expression profiles of 21 plasma miRs related to glycemic and lipid metabolism, adiposity, and inflammation were evaluated in relation to cardiometabolic risk. Individuals were distributed into groups according to diagnosis of metabolic syndrome (MetS). The Stata Somersd module was used to calculate confidence intervals for Kendall's tau-a to estimate the correlations among variables.

RESULTS

Differences in the plasma expression were observed in two of the 21 miRs evaluated according to the MetS presence in participants. Individuals with MetS showed higher expression of miR-30a and miR-122 than individuals without MetS.

CONCLUSIONS

Considering that miR-30, and miR-122 were altered due to MetS, these miRs may be potential biomarkers for MetS in older adults.

Molecular mechanisms of noncoding RNA and epigenetic regulation in obesity with consequent diabetes mellitus development

Diabetes mellitus (DM) and obesity have become two of the most prevalent and challenging diseases worldwide, with increasing incidence and serious complications. Recent studies have shown that noncoding RNA (ncRNA) and epigenetic regulation play crucial roles in the pathogenesis of DM complicated by obesity. Identification of the involvement of ncRNA and epigenetic regulation in the pathogenesis of diabetes with obesity has opened new avenues of investigation. Targeting these mechanisms with small molecules or RNA-based therapies may provide a more precise and effective approach to diabetes treatment than traditional therapies. In this review, we discuss the molecular mechanisms of ncRNA and epigenetic regulation and their potential therapeutic targets, and the research prospects for DM complicated with obesity.

Clinical relevance of circulating non-coding RNAs in metabolic diseases: Emphasis on obesity, diabetes, cardiovascular diseases and metabolic syndrome

Non-coding RNAs (ncRNAs) participate in the regulation of several cellular processes including transcription, RNA processing and genome rearrangement. The aberrant expression of ncRNAs is associated with several pathological conditions. In this review, we focused on recent information to elucidate the role of various regulatory ncRNAs i.e., micro RNAs (miRNAs), circular RNAs (circRNAs) and long-chain non-coding RNAs (lncRNAs), in metabolic diseases, e.g., obesity, diabetes mellitus (DM), cardiovascular diseases (CVD) and metabolic syndrome (MetS). The mechanisms by which ncRNAs participated in disease pathophysiology were also highlighted. miRNAs regulate the expression of genes at transcriptional and translational levels. circRNAs modulate the regulation of gene expression via miRNA sponging activity, interacting with RNA binding protein and polymerase II transcription regulation. lncRNAs regulate the expression of genes by acting as a protein decoy, miRNA sponging, miRNA host gene, binding to miRNA response elements (MRE) and the recruitment of transcriptional element or chromatin modifiers. We examined the role of ncRNAs in the disease pathogenesis and their potential role as molecular markers for diagnosis, prognosis and therapeutic targets. We showed the involvement of ncRNAs in the onset of obesity and its progression to MetS and CVD. miRNA-192, miRNA-122, and miRNA-221 were dysregulated in all these metabolic diseases. Other ncRNAs, implicated in at least three diseases include miRNA-15a, miRNA-26, miRNA-27a, miRNA-320, and miRNA-375. Dysregulation of ncRNAs increased the risk of development of DM and MetS and its progression to CVD in obese individuals. Hence, these molecules are potential targets to arrest or delay the progression of metabolic diseases.

Circulating MicroRNA-30a, Beclin1 and Their Association with Different Variables in Females with Metabolically Healthy /Unhealthy Obesity

Background

Obesity is associated with metabolic and cardiovascular co-morbidities. It is important to determine the factors associated with metabolic derangement in obesity. Autophagy plays a major role in the pathogenesis of metabolic syndrome. MicroRNA-30a targets beclin1, the main regulator of autophagy.

Purpose

We assess circulating microRNA-30a and serum beclin1 in women with metabolically unhealthy obesity (MUO), women with metabolically healthy obesity (MHO) and non-obese healthy control and determine their relationship with different clinical and metabolic variables in women with obesity.

Patients and Methods

This cross-sectional study included 34 women with MHO, 34 with MUO, and 20 healthy non-obese women. Blood pressure, body mass index (BMI), and waist circumference were recorded. Glycemic and lipid indices, urinary albumin-to-creatinine ratio, ALT, AST, microRNA-30a expression in serum were measured using real-time polymerase chain reaction and beclin1 by enzyme-linked immunosorbent assay were measured.

Results

The expression of microRNA-30a was significantly higher, and beclin1 level was significantly lower in women with MUO compared to those in women with MHO (P<0.001; for both). People with MUO were significantly older (P<0.001) and had higher TSH (P=0.006), HbA1c (P<0.001), triglyceride (P<0.001), and ALT (P<0.001) compared to women with MHO. However, there was no significant difference between the two groups in any anthropometric measurements, HDL-C or LDL-C. In univariate analyses, age, ALT, TSH, microRNA-30a, and beclin1 were significantly correlated with the MUO phenotype (P<0.001; for all). Significance was confirmed in the multivariate analysis for microRNA-30a (95% CI 1.317-28.252; P=0.021).

Conclusion

MicroRNA-30a, beclin1, age, and ALT and TSH levels were significantly associated with the MUO phenotype, among which microRNA-30a was the best indicator of metabolic syndrome in women with obesity.

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.

Human umbilical cord mesenchymal stromal cell small extracellular vesicle transfer of microRNA-223-3p to lung epithelial cells attenuates inflammation in acute lung injury in mice

BACKGROUND

Acute lung injury (ALI), manifested as strong pulmonary inflammation and alveolar epithelial damage, is a life-threatening disease with high morbidity and mortality. Small extracellular vesicles (sEVs), secreted by multiple types of cells, are critical cellular communication mediators and can inhibit inflammation by transferring bioactive molecules, such as microRNAs (miRNAs). Thus, we hypothesized that sEVs derived from mesenchymal stromal cells (MSC sEVs) could transfer miRNAs to attenuate inflammation of lung epithelial cells during ALI.

METHODS

C57BL/6 male mice were intratracheally administered LPS (10 mg/kg). Six hours later, the mice were randomly administered with MSC sEVs (40 µg per mouse in 150 µl of saline), which were collected by ultracentrifugation. Control group received saline administration. After 48 h, the mice were sacrificed to evaluate pulmonary microvascular permeability and inflammatory responses. In vitro, A549 cells and primary human small airway epithelial cells (SAECs) were stimulated with LPS with or without MSC sEVs treatment.

RESULTS

In vitro, MSC sEVs could also inhibit the inflammation induced by LPS in A549 cells and SAECs (reducing TNF-α, IL-1β, IL-6 and MCP-1). Moreover, MSC sEV treatment improved the survival rate, alleviated pulmonary microvascular permeability, and inhibited proinflammatory responses (reducing TNF-α, IL-1β, IL-6 and JE-1) in ALI mice. Notably, miR-223-3p was found to be served as a critical mediator in MSC sEV-induced regulatory effects through inhibition of poly (adenosine diphosphate-ribose) polymerase-1 (PARP-1) in lung epithelial cells.

CONCLUSIONS

Overall, these findings suggest that MSC sEVs may offer a novel promising strategy for ALI.

A Review of micro RNAs changes in T2DM in animals and humans

Type 2 diabetes mellitus (T2DM) and its associated complications have become a crucial public health concern in the world. According to the literature, chronic inflammation and the progression of T2DM have a close relationship. Accumulated evidence suggests that inflammation enhances the insulin secretion lost by islets of Langerhans and the resistance of target tissues to insulin action, which are two critical features in T2DM development. Based on recently highlighted research that plasma concentration of inflammatory mediators such as tumor necrosis factor α and interleukin-6 are elevated in insulin-resistant and T2DM, and it raises novel question marks about the processes causing inflammation in both situations. Over the past few decades, microRNAs (miRNAs), a class of short, noncoding RNA molecules, have been discovered to be involved in the regulation of inflammation, insulin resistance, and T2DM pathology. These noncoding RNAs are specifically comprised of RNA-induced silencing complexes and regulate the expression of specific protein-coding genes through various mechanisms. There is extending evidence that describes the expression profile of a special class of miRNA molecules altered during T2DM development. These modifications can be observed as potential biomarkers for the diagnosis of T2DM and related diseases. In this review study, after reviewing the possible mechanisms involved in T2DM pathophysiology, we update recent information on the miRNA roles in T2DM, inflammation, and insulin resistance.

The link between glycemic control measures and eye microvascular complications in a clinical cohort of type 2 diabetes with microRNA-223-3p signature

BACKGROUND

Type 2 diabetes (T2D) is a critical healthcare challenge and priority in Qatar which is listed amongst the top 10 countries in the world, with its prevalence presently at 17% double the global average. MicroRNAs (miRNAs) are implicated in the pathogenesis of (T2D) and long-term microvascular complications including diabetic retinopathy (DR).

METHODS

In this study, a T2D cohort that accurately matches the characteristics of the general population was employed to find microRNA (miRNA) signatures that are correlated with glycemic and β cell function measurements. Targeted miRNA profiling was performed in (471) T2D individuals with or without DR and (491) (non-diabetic) healthy controls from the Qatar Biobank. Discovery analysis identified 20 differentially expressed miRNAs in T2D compared to controls, of which miR-223-3p was significantly upregulated (fold change:5.16, p = 3.6e-02) and positively correlated with glucose and hemoglobin A1c (HbA1c) levels (p-value = 9.88e-04 and 1.64e-05, respectively), but did not show any significant associations with insulin or C-peptide. Accordingly, we performed functional validation using a miR-223-3p mimic (overexpression) under control and hyperglycemia-induced conditions in a zebrafish model.

RESULTS

Over-expression of miR-223-3p alone was associated with significantly higher glucose (42.7 mg/dL, n = 75 vs 38.7 mg/dL, n = 75, p = 0.02) and degenerated retinal vasculature, and altered retinal morphology involving changes in the ganglion cell layer and inner and outer nuclear layers. Assessment of retinal angiogenesis revealed significant upregulation in the expression of vascular endothelial growth factor and its receptors, including kinase insert domain receptor. Further, the pancreatic markers, pancreatic and duodenal homeobox 1, and the insulin gene expressions were upregulated in the miR-223-3p group.

CONCLUSION

Our zebrafish model validates a novel correlation between miR-223-3p and DR development. Targeting miR-223-3p in T2D patients may serve as a promising therapeutic strategy to control DR in at-risk individuals.

Competing Endogenous RNA Regulatory Networks of hsa_circ_0126672 in Pathophysiology of Coronary Heart Disease

Coronary heart disease (CHD) is a global health concern, and its molecular origin is not fully elucidated. Dysregulation of ncRNAs has been linked to many metabolic and infectious diseases. This study aimed to explore the role of circRNAs in the pathogenesis of CHD and predicted a candidate circRNA that could be targeted for therapeutic approaches to the disease. circRNAs associated with CHD were identified and CHD gene expression profiles were obtained, and analyzed with GEO2R. In addition, differentially expressed miRNA target genes (miR-DEGs) were identified and subjected to functional enrichment analysis. Networks of circRNA/miRNA/mRNA and the miRNA/affected pathways were constructed. Furthermore, a miRNA/mRNA homology study was performed. We identified that hsa_circ_0126672 was strongly associated with the CHD pathology by competing for endogenous RNA (ceRNA) mechanisms. hsa_circ_0126672 characteristically sponges miR-145-5p, miR-186-5p, miR-548c-3p, miR-7-5p, miR-495-3p, miR-203a-3p, and miR-21. Up-regulation of has_circ_0126672 affected various CHD-related cellular functions, such as atherosclerosis, JAK/STAT, and Apelin signaling pathways. Our results also revealed a perfect and stable interaction for the hybrid of miR-145-5p with NOS1 and RPS6KB1. Finally, miR-145-5p had the highest degree of interaction with the validated small molecules. Henchashsa_circ_0126672 and target miRNAs, notably miR-145-5p, could be good candidates for the diagnosis and therapeutic approaches to CHD.

Elevated Expression of miR-296 in Human Placentas and Serum Samples From Pregnancies With Preeclampsia

Background: Preeclampsia (PE) is a hypertensive disorder of pregnancy characterized by widespread maternal endothelial dysfunction. Although clinical signs subside following delivery, long-term risks associated with PE include hypertension, stroke, and cardiovascular disease. MicroRNAs (miRNAs) are emerging as critical regulators of biological function, and while alterations to the miRNAs have been described in the context of pregnancy and PE, the postpartum implications of PE on miRNA expression are unknown. In the present study, we aimed to determine the clinical performance of miR-296 in PE. Methods: First, the clinical information and outcomes of all the participants were collected and analyzed. Afterward, the miR-296 expressions in the serum samples from healthy pregnant women and women with PE at different periods were detected using quantitative real-time polymerase chain reaction (qRT-PCR). Then, the receive operation characteristic (ROC) curve was used to determine the diagnostic value of miR-296 in PE. Finally, the at-term placentals were collected, the expressions of miR-296 in different groups were compared at first blood collection and at delivery. Results: In this study, we found that miR-296 expression was significantly increased in the placenta samples from PE patients compared with that in healthy controls both in early onset group (EOPE, p < 0.01) and late onset group (LOPE, p < 0.01). Furthermore, results of ROC analysis showed miR-296 might be a putative biomarker for early onset preeclampsia and late onset preeclampsia diagnosis with an area under the curve (AUC) of 0.84 (95% confidence interval 0.75-0.92) and 0.85 (95% confidence interval 0.77-0.93). Last but not the least, the expressions of miR-296 were significantly increased (p < 0.05) in serum samples of EOPE and LOPE patients (p < 0.001), and serum and placental levels of the miR-296 was positively correlated for EOPE (r = 0.5574, p < 0.001) and LOPE (r = 0.6613, p < 0.001) patients, respectively. Meanwhile, compared with those at first blood collection, the expression of miR-296 in EOPE (p = 0.05) and LOPE (p = 0.01) were significantly decreased at delivery. Conclusion: miR-296 may function as a putative diagnostic biomarker for PE and contribute to identifying at-risk mothers in pregnancy.

Role of Adipose Tissue microRNAs in the Onset of Metabolic Diseases and Implications in the Context of the DOHaD

The worldwide epidemic of obesity is associated with numerous comorbid conditions, including metabolic diseases such as insulin resistance and diabetes, in particular. The situation is likely to worsen, as the increase in obesity rates among children will probably lead to an earlier onset and more severe course for metabolic diseases. The origin of this earlier development of obesity may lie in both behavior (changes in nutrition, physical activity, etc.) and in children's history, as it appears to be at least partly programmed by the fetal/neonatal environment. The concept of the developmental origin of health and diseases (DOHaD), involving both organogenesis and epigenetic mechanisms, encompasses such programming. Epigenetic mechanisms include the action of microRNAs, which seem to play an important role in adipocyte functions. Interestingly, microRNAs seem to play a particular role in propagating local insulin resistance to other key organs, thereby inducing global insulin resistance and type 2 diabetes. This propagation involves the active secretion of exosomes containing microRNAs by adipocytes and adipose tissue-resident macrophages, as well as long-distance communication targeting the muscles and liver, for example. Circulating microRNAs may also be useful as biomarkers for the identification of populations at risk of subsequently developing obesity and metabolic diseases.

Current Insights into miRNA and lncRNA Dysregulation in Diabetes: Signal Transduction, Clinical Trials and Biomarker Discovery

Diabetes is one of the most frequently occurring metabolic disorders, affecting almost one tenth of the global population. Despite advances in antihyperglycemic therapeutics, the management of diabetes is limited due to its complexity and associated comorbidities, including diabetic neuropathy, diabetic nephropathy and diabetic retinopathy. Noncoding RNAs (ncRNAs), including microRNAs (miRNAs) and long noncoding RNAs (lncRNAs), are involved in the regulation of gene expression as well as various disease pathways in humans. Several ncRNAs are dysregulated in diabetes and are responsible for modulating the expression of various genes that contribute to the 'symptom complex' in diabetes. We review various miRNAs and lncRNAs implicated in diabetes and delineate ncRNA biological networks as well as key ncRNA targets in diabetes. Further, we discuss the spatial regulation of ncRNAs and their role(s) as prognostic markers in diabetes. We also shed light on the molecular mechanisms of signal transduction with diabetes-associated ncRNAs and ncRNA-mediated epigenetic events. Lastly, we summarize clinical trials on diabetes-associated ncRNAs and discuss the functional relevance of the dysregulated ncRNA interactome in diabetes. This knowledge will facilitate the identification of putative biomarkers for the therapeutic management of diabetes and its comorbidities. Taken together, the elucidation of the architecture of signature ncRNA regulatory networks in diabetes may enable the identification of novel biomarkers in the discovery pipeline for diabetes, which may lead to better management of this metabolic disorder.

Exosomal noncoding RNAs in colorectal cancer: An overview of functions, challenges, opportunities, and clinical applications

Colorectal cancer (CRC) is the third most threatening malignancy worldwide. Colorectal tumors transfer information with their tumor microenvironment (TME) and communicate together which can be detected through exosome transmission. Exosomes are important regulators made by different types of cells in all body fluids containing RNA, DNA, metabolites, and proteins. Recently, Exosome-derived noncoding RNAs (ncRNAs) applications have gained great consideration based on their potential role in the different pathological processes. Therefore, in this review, we summarized the recent discoveries on exosomal ncRNAs function in CRC initiation and development, and drug resistance to provide a novel insight into exosomal ncRNAs' clinical application and their potential to be biomarkers for CRC patients.

A comprehensive overview on Micro RNA signature in type 2 diabetes Mellitus and its complications

MicroRNAs (miRNAs) are small endogenous, non-coding RNA molecules that can modulate the expression of their target genes. Since its discovery, an enormous breakthrough has been established regarding its biogenesis and pathophysiological action, which has revolutionized the field of molecular biology. In addition, recent studies have identified the existence of stable extracellular/circulating miRNAs tissues and in biological fluids like blood where they are safeguarded from endogenous ribonuclease activity. Type 2 diabetes mellitus (T2DM) has emerged as a prime health issue worldwide. Incidence has increased considerably over the past decade. There are various tests that have been employed to diagnose T2DM. But for early detection and development, the establishment of biomarkers are of paramount importance. Contemporary evidence also validates the signature of a set of this epigenetic factor miRNA in the development of various diseases, including T2DM. This article reviews the contemporary corroboration associating miRNAs and T2DM and emphasizes the potential role of miRNA as a circulatory biomarker that could alert the growing prevalence of T2DM. Also, it acknowledges the valuable compendium of information regarding biogenesis and functional role of circulating miRNA in insulin resistance which is intimately linked to T2DM.

hsa-miR-607, lncRNA TUG1 and hsa_circ_0071106 can be combined as biomarkers in type 2 diabetes mellitus

Type 2 diabetes mellitus (T2DM) is a multifactorial disorder that leads to alterations in gene regulation. ncRNAs have the characteristics of tissue specificity, disease specificity, timing specificity, high stability and post transcriptional regulation effect. These preconditions are more conducive to promote ncRNA to become a new biomarker for clinical diagnosis. Our study aims to explore the relationship between circRNA, lncRNA, miRNA and T2DM, and to evaluate their diagnostic value for T2DM. A total of 101 pairs of T2DM and controls were conducted in the study. QRT-PCR was used to study the differential expression of circRNAs, miRNAs and lncRNAs. ROC curve was used to estimate their diagnostic value in T2DM. Compared with healthy controls, the expression levels of hsa_circ_0071106, hsa_circ_0000284, hsa_circ_0071271, hsa-miR-29a-5p, hsa-miR-3690, hsa-miR-607, lncRNA MEG3 and lncRNA TUG1were higher in T2DM (all P < 0.05). The AUCs of hsa_circ_0071106, hsa-miR-607 and lncRNA TUG1 for diagnosis of T2DM were 0.563,0.645 and 0.642, respectively. The combined AUC of hsa-miR-607, lncRNA TUG1 and hsa_circ_0071106 was 0.798 ([0.720~0.875], P < 0.001). Moreover, the sensitivity of combined diagnosis was 75.2% and the specificity was 100.0%. The levels of lncRNA TUG1, hsa-miR-607 and hsa_circ_0071106 in peripheral blood have potential clinical diagnostic value for T2DM.

Circulating microRNAs as clinically useful biomarkers for Type 2 Diabetes Mellitus: miRNomics from bench to bedside

Type 2 diabetes (T2D), a chronic metabolic disease, has attained the status of a global epidemic with steadily increasing incidence worldwide. Improved diagnosis, stratification and prognosis of T2D patients and the development of more effective treatments are needed. In this era of personalized medicine, the discovery and evaluation of innovative circulating biomarkers can be an effective tool for better stratification, prognosis and therapeutic selection/management of T2D patients. MicroRNAs (miRNAs), a class of small non-coding RNAs that modulate gene expression, have been investigated as potential circulating biomarkers in T2D. Several studies have investigated the expression of circulating miRNAs in T2D patients from various biological fluids, including plasma and serum, and have demonstrated their potential as diagnostic and prognostic biomarkers, as well as biomarkers of response to therapy. In this review, we provide an overview of the current state of knowledge, focusing on circulating miRNAs that have been consistently expressed in at least two independent studies, in order to identify a set of consistent biomarker candidates in T2D. The expression levels of miRNAs, correlation with clinical parameters, functional roles of miRNAs and their potential as biomarkers are reported. A systematic literature search and assessment of studies led to the selection and review of 10 miRNAs (miR-126-3p, miR-223-3p, miR-21-5p, miR-15a-5p, miR-24-3p, miR-34a-5p, miR-146a-5p, miR-148a-3p, miR-30d-5p and miR-30c-5p). We also present technical challenges and our thoughts on the potential validation of circulating miRNAs and their application as biomarkers in the context of T2D.

Associations of plasma miRNAs with waist circumference and insulin resistance among women with polycystic ovary syndrome - Pilot study

BACKGROUND

Insulin resistance (IR) and central obesity are common in polycystic ovary syndrome (PCOS), but pathomechanisms for IR in PCOS are not established. Circulating microRNAs (miRNAs) are non-invasive biomarkers of epigenetic regulation that may contribute to the pathogenesis of IR and central adiposity in PCOS.

METHODS

We conducted a pilot study to examine associations of circulating miRNAs with IR and central adiposity among women with PCOS (n = 11) using high-throughput miRNA sequencing. We fit generalized linear models examining associations of waist circumference and HOMA-IR with plasma miRNAs. We used false discovery rate (FDR)-adjusted cutoff p < 0.1 to correct for multiple testing. We used miRDB's Gene Ontology (GO) tool to identify predicted pathways for top hits.

RESULTS

Mean age and BMI of participants were 27.9 years and 32.5 kg/m2, respectively. Lower levels of miR-1294 were associated with higher waist circumference (β = -0.10, FDR = 0.095). While no miRNAs were associated with HOMA-IR at our FDR cut off <0.1, 11 miRNAs were associated with waist circumference and 14 miRNAs with HOMA-IR at unadjusted p < 0.01, including members of the highly conserved miR-17/92 cluster and miR-1294 (β = -0.10, p < 0.001). The GO analysis of miR-1294 identified 54 overrepresented pathways, including "negative regulation of insulin receptor signaling" (FDR = 0.019), and 6 underrepresented pathways.

CONCLUSIONS

Plasma miR-1294 along with members of the miR-17/92 cluster and miRNAs involved in insulin signaling may be associated with central obesity and insulin resistance in PCOS. Larger studies among women with and without PCOS are needed to validate these findings.

Trends in insulin resistance: insights into mechanisms and therapeutic strategy

The centenary of insulin discovery represents an important opportunity to transform diabetes from a fatal diagnosis into a medically manageable chronic condition. Insulin is a key peptide hormone and mediates the systemic glucose metabolism in different tissues. Insulin resistance (IR) is a disordered biological response for insulin stimulation through the disruption of different molecular pathways in target tissues. Acquired conditions and genetic factors have been implicated in IR. Recent genetic and biochemical studies suggest that the dysregulated metabolic mediators released by adipose tissue including adipokines, cytokines, chemokines, excess lipids and toxic lipid metabolites promote IR in other tissues. IR is associated with several groups of abnormal syndromes that include obesity, diabetes, metabolic dysfunction-associated fatty liver disease (MAFLD), cardiovascular disease, polycystic ovary syndrome (PCOS), and other abnormalities. Although no medication is specifically approved to treat IR, we summarized the lifestyle changes and pharmacological medications that have been used as efficient intervention to improve insulin sensitivity. Ultimately, the systematic discussion of complex mechanism will help to identify potential new targets and treat the closely associated metabolic syndrome of IR.

Effect of Anti-Osteoporotic Treatments on Circulating and Bone MicroRNA Patterns in Osteopenic ZDF Rats

Bone fragility is an adverse outcome of type 2 diabetes mellitus (T2DM). The underlying molecular mechanisms have, however, remained largely unknown. MicroRNAs (miRNAs) are short non-coding RNAs that control gene expression in health and disease states. The aim of this study was to investigate the genome-wide regulation of miRNAs in T2DM bone disease by analyzing serum and bone tissue samples from a well-established rat model of T2DM, the Zucker Diabetic Fatty (ZDF) model. We performed small RNA-sequencing analysis to detect dysregulated miRNAs in the serum and ulna bone of the ZDF model under placebo and also under anti-sclerostin, PTH, and insulin treatments. The dysregulated circulating miRNAs were investigated for their cell-type enrichment to identify putative donor cells and were used to construct gene target networks. Our results show that unique sets of miRNAs are dysregulated in the serum (n = 12, FDR < 0.2) and bone tissue (n = 34, FDR < 0.2) of ZDF rats. Insulin treatment was found to induce a strong dysregulation of circulating miRNAs which are mainly involved in metabolism, thereby restoring seven circulating miRNAs in the ZDF model to normal levels. The effects of anti-sclerostin treatment on serum miRNA levels were weaker, but affected miRNAs were shown to be enriched in bone tissue. PTH treatment did not produce any effect on circulating or bone miRNAs in the ZDF rats. Altogether, this study provides the first comprehensive insights into the dysregulation of bone and serum miRNAs in the context of T2DM and the effect of insulin, PTH, and anti-sclerostin treatments on circulating miRNAs.

Extracellular vesicles-incorporated microRNA signature as biomarker and diagnosis of prediabetes state and its complications

Extracellular vesicles (EVs) are small anuclear vesicles, delimited by a lipid bilayer, released by almost all cell types, carrying functionally active biological molecules that can be transferred to the neighbouring or distant cells, inducing phenotypical and functional changes, relevant in various physio-pathological conditions. The microRNAs are the most significant active components transported by EVs, with crucial role in intercellular communication and significant effects on recipient cells. They may also server as novel valuable biomarkers for the diagnosis of metabolic disorders. Moreover, EVs are supposed to mediate type 2 diabetes mellitus (T2DM) risk and its progress. The T2DM development is preceded by prediabetes, a state that is associated with early forms of nephropathy and neuropathy, chronic kidney disease, diabetic retinopathy, and increased risk of macrovascular disease. Although the interest of scientists was focused not only on the pathogenesis of diabetes, but also on the early diagnosis, little is known about EVs-incorporated microRNA involvement in prediabetes state and its microvascular and macrovascular complications. Here, we survey the biogenesis, classification, content, biological functions and the most popular primary isolation methods of EVs, review the EVs-associated microRNA profiling connexion with early stages of diabetes and discuss the role of EVs containing specific microRNAs in prediabetes complications.

Detection of a miRNA biomarker for cancer diagnosis using SERS tags and magnetic separation

Detection of miR-29a, a biomarker of cancers, using SERS tags and magnetic separation is described. The assay was designed to detect the miR-29a sequence by taking the complementary sequence and splitting it into a capture and detection probe. The SERS tags comprised the highly Raman active molecule 4-mercaptobenzoic acid (4-MBA) and DNA detection probes assembled onto the surface of gold nanorods (AuNRs) through the self-assembly process. The capture DNA conjugated magnetic nanoparticles (MNPs) were applied as capture probes. The detection was based on the hybridisation and sandwich complex formation. The resultant hybridisation-dependent complexes were recovered and enriched from the samples by magnetic separation. The enriched solution containing target miRNA hybridised with capture probes were dropped on a foil-covered slide to form a droplet for SERS analysis. A characteristic spectrum of 4-MBA was observed to indicate the presence of the miR-29a in the samples. The sensitivity of the assay is examined by measuring the SERS signal of the samples containing different concentrations of the miR-29a. The SERS intensity appears to increase with the concentration of miR-29a. The limit of detection (LOD) was found to be 10 pM without any amplification process. In addition, the selectivity and feasibility of the assay in complex media are evaluated with the non-target miRNAs comprising different sequences from the target miR-29a. The system was capable of detecting the target miR-29a specifically with high selectivity. These results suggest that this solution-based SERS platform has a significant capability for simple, sensitive, and selective miR-29a analysis.

miRNA Expression Profiling in Subcutaneous Adipose Tissue of Monozygotic Twins Discordant for HIV Infection: Validation of Differentially Expressed miRNA and Bioinformatic Analysis

Combined AntiRetroviral Treatments (cARTs) used for HIV infection may result in varied metabolic complications, which in some cases, may be related to patient genetic factors, particularly microRNAs. The use of monozygotic twins, differing only for HIV infection, presents a unique and powerful model for the controlled analysis of potential alterations of miRNAs regulation consequent to cART treatment. Profiling of 2578 mature miRNA in the subcutaneous (SC) adipose tissue and plasma of monozygotic twins was investigated by the GeneChip® miRNA 4.1 array. Real-time PCR and ddPCR experiments were performed in order to validate differentially expressed miRNAs. Target genes of deregulated miRNAs were predicted by the miRDB database (prediction score > 70) and enrichment analysis was carried out with g:Profiler. Processes in SC adipose tissue most greatly affected by miRNA up-regulation included (i) macromolecular metabolic processes, (ii) regulation of neurogenesis, and (iii) protein phosphorylation. Furthermore, KEGG analysis revealed miRNA up-regulation involvement in (i) insulin signaling pathways, (ii) neurotrophin signaling pathways, and (iii) pancreatic cancer. By contrast, miRNA up-regulation in plasma was involved in (i) melanoma, (ii) p53 signaling pathways, and (iii) focal adhesion. Our findings suggest a mechanism that may increase the predisposition of HIV+ patients to insulin resistance and cancer.

Regulation of microRNAs in Alzheimer´s disease, type 2 diabetes, and aerobic exercise training

Alzheimer's disease (AD) is the most common type of dementia. The evolution and aggregation of amyloid beta (β) oligomers is linked to insulin resistance in AD, which is also the major characteristic of type 2 diabetes (T2D). Being physically inactive can contribute to the development of AD and/or T2D. Aerobic exercise training (AET), a type of physical exercise, can be useful in preventing or treating the negative outcomes of AD and T2D. AD, T2D and AET can regulate the expression of microRNAs (miRNAs). Here, we review some of the changes in miRNAs expression regulated by AET, AD and T2D. MiRNAs play an important role in the gene regulation of key signaling pathways in both pathologies, AD and T2D. MiRNA dysregulation is evident in AD and has been associated with several neuropathological alterations, such as the development of a reactive gliosis. Expression of miRNAs are associated with many pathophysiological mechanisms involved in T2D like insulin synthesis, insulin resistance, glucose intolerance, hyperglycemia, intracellular signaling, and lipid profile. AET regulates miRNAs levels. We identified 5 miRNAs (miR-21, miR-29a/b, miR-103, miR-107, and miR-195) that regulate gene expression and are modulated by AET on AD and T2D. The identified miRNAs are potential targets to treat the symptoms of AD and T2D. Thus, AET is a non-pharmacological tool that can be used to prevent and fight the negative outcomes in AD and T2D.

Noncoding RNAs from tissue-derived small extracellular vesicles: Roles in diabetes and diabetic complications

Diabetes is a systemic disease, and its progression involves multiple organ dysfunction. However, the exact mechanisms underlying pathological progression remain unclear. Small extracellular vesicles (sEVs) mediate physiological and pathological signaling communication between organs and have been shown to have important regulatory roles in diabetes and its complications in recent years. In particular, the majority of studies in the diabetes-related research field have focused on the noncoding RNAs carried by sEVs. Researchers found that noncoding RNA sorting into sEVs is not random but selective. Both tissue origin differences and environmental variations affect the cargo of sEVs. In addition, the function of sEVs differs according to the tissue they derive from; for example, sEVs derived from adipose tissue regulate insulin sensitivity in the periphery, while sEVs derived from bone marrow promote β-cell regeneration. Therefore, understanding the roles of sEVs from different tissues is important for elucidating their molecular mechanisms and is necessary for the application of sEVs as therapeutic agents for diabetes treatment in the future. In this review, we summarized current studies on the mechanisms of noncoding RNA sorting into sEVs, as well as the research progress on the effects of sEVs from different tissue origins and noncoding RNAs in diabetes and diabetic complications. The knowledge of noncoding RNAs in sEVs will help us better understand the role of sEVs in the diabetes progression.

Bisphenol A induces miR-708-5p through an ER stress-mediated mechanism altering neuronatin and neuropeptide Y expression in hypothalamic neuronal models

Bisphenol A (BPA) is an endocrine disrupting chemical that promotes obesity. It acts on the hypothalamus by increasing expression of the orexigenic neuropeptides, Npy and Agrp. Exactly how BPA dysregulates energy homeostasis is not completely clear. Since microRNAs (miRNA) have emerged as crucial weight regulators, the question of whether BPA could alter hypothalamic miRNA profiles was examined. Treatment of the mHypoA-59 cell line with 100 μM BPA altered a specific subset of miRNAs, and the most upregulated was miR-708-5p. BPA was found to increase the levels of miR-708-5p, and its parent gene Odz4, through the ER stress-related protein Chop. Overexpression of an miR-708-5p mimic resulted in a reduction of neuronatin, a proteolipid whose loss of expression is associated with obesity, and an increase in orexigenic Npy expression, thus potentially increasing feeding through converging regulatory pathways. Therefore, hypothalamic exposure to BPA can increase miR-708-5p that controls neuropeptides directly linked to obesity.

In Vivo Reductionist Approach Identifies miR-15a Protecting Mice From Obesity

Obesity is a growing medical and social problem worldwide. The control of energy homeostasis in the brain is achieved by various regions including the arcuate hypothalamic nucleus (ARH). The latter comprises a number of neuronal populations including the first order metabolic neurons, appetite-stimulating agouti-related peptide (AgRP) neurons and appetite-suppressing proopiomelanocortin (POMC) neurons. Using an in vivo reductionist approach and POMC^Cre-dependent CRISPR-Cas9, we demonstrate that miR-15a-5p protects from obesity. Moreover, we have identified Bace1, a gene previously linked to energy metabolism imbalance, as a direct target of miR-15a-5p. This work warrants further investigations of non-coding RNA-mediated regulation of energy homeostasis and might contribute to the development of novel therapeutic approaches to treat metabolic diseases.

Down-Regulation of miR-138 Alleviates Inflammatory Response and Promotes Wound Healing in Diabetic Foot Ulcer Rats via Activating PI3K/AKT Pathway and hTERT

OBJECTIVE

To study the role of miR-138 on the repair of diabetic foot ulcer (DFU) and further to explore its possible mechanism.

MATERIALS AND METHODS

miR-138 inhibitor, IGF-1, LY294002 were used in DFU rat mode, and the mRNA expression of miR-138 was detected. HE staining was used to observe the histological changes of skin ulcer in rats. The level of inflammation, wound healing, and blood vessel formation-related factors were detected by ELISA and immunohistochemical. The expression of VEGF and PI3K/AKT pathway-related proteins were detected by Western blot. To further determine the underlying mechanism of miR-138 in the repair of DFU, telomerase inhibitor BIBR-1232 was used in HUVECs. Dual-luciferase assay was used to determine the target relationship between miR-138 and hTERT. CCK-8, transwell, and tube formation assays were conducted to observe the biological behavior of HUVECs. Inflammatory cytokines and PI3K/AKT pathway-related proteins were also measured by ELISA and Western blot.

RESULTS

The mRNA expression of miR-138 in DFU rat was increased and ulcer of diabetic foot rats was improved after silencing miR-138. The results of cellular bioactivity in vitro experiment were consistent with that in vivo. Meanwhile, after silencing miR-138, the level of inflammatory cytokines was decreased, while the level of anti-inflammatory and healing factors was increased in vivo and vitro. Moreover, the ratios of p-PI3K/PI3K and p-AKT/AKT were upregulated after treated with miR-138 inhibitor and miR-138 was negatively regulated the expression of hTERT. However, the inhibitory effect on inflammatory response and the promotion effect on wound healing of miR-138 inhibitor were reversed by LY294002 and BIBR-1232.

CONCLUSION

Down-regulation of miR-138 could alleviate inflammatory response and promote wound healing in DFU rats by activating PI3K/AKT pathway and hTERT.

Association of circulating miRNAS in patients with Alstrőm and Bardet-Biedl syndromes with clinical course parameters

BACKGROUND

Patients with the rare syndromic forms of monogenic diabetes: Alström syndrome (ALMS) and Bardet-Biedl syndrome (BBS) have multiple metabolic abnormalities, including early-onset obesity, insulin resistance, lipid disorders and type 2 diabetes mellitus. The aim of this study was to determine if the expression of circulating miRNAs in patients with ALMS and BBS differs from that in healthy and obese individuals and determine if miRNA levels correlate with metabolic tests, BMI-SDS and patient age.

METHODS

We quantified miRNA expression (Qiagen, Germany) in four groups of patients: with ALMS (n=13), with BBS (n=7), patients with obesity (n=19) and controls (n=23). Clinical parameters including lipids profile, serum creatinine, cystatin C, fasting glucose, insulin and C-peptide levels, HbA1c values and insulin resistance (HOMA-IR) were assessed in patients with ALMS and BBS.

RESULTS

We observed multiple up- or downregulated miRNAs in both ALMS and BBS patients compared to obese patients and controls, but only 1 miRNA (miR-301a-3p) differed significantly and in the same direction in ALMS and BBS relative to the other groups. Similarly, 1 miRNA (miR-92b-3p) was dysregulated in the opposite directions in ALMS and BBS patients, but diverged from 2 other groups. We found eight miRNAs (miR-30a-5p, miR-92b-3p, miR-99a-5p, miR-122-5p, miR-192-5p, miR-193a-5p, miR-199a-3p and miR-205-5p) that significantly correlated with at least of the analyzed clinical variables representing an association with the course of the diseases.

CONCLUSIONS

Our results show for the first time that serum miRNAs can be used as available indicators of disease course in patients with ALMS and BBS syndromes.

Research progress on exosomes/microRNAs in the treatment of diabetic retinopathy

Diabetic retinopathy (DR) is the leakage and obstruction of retinal microvessels caused by chronic progressive diabetes that leads to a series of fundus lesions. If not treated or controlled, it will affect vision and even cause blindness. DR is caused by a variety of factors, and its pathogenesis is complex. Pericyte-related diseases are considered to be an important factor for DR in many pathogeneses, which can lead to DR development through direct or indirect mechanisms, but the specific mechanism remains unclear. Exosomes are small vesicles of 40-100 nm. Most cells can produce exosomes. They mediate intercellular communication by transporting microRNAs (miRNAs), proteins, mRNAs, DNA, or lipids to target cells. In humans, intermittent hypoxia has been reported to alter circulating excretory carriers, increase endothelial cell permeability, and promote dysfunction in vivo. Therefore, we believe that the changes in circulating exocrine secretion caused by hypoxia in DR may be involved in its progress. This article examines the possible roles of miRNAs, proteins, and DNA in DR occurrence and development and discusses their possible mechanisms and therapy. This may help to provide basic proof for the use of exocrine hormones to cure DR.

miRetrieve-an R package and web application for miRNA text mining

microRNAs (miRNAs) regulate gene expression and thereby influence biological processes in health and disease. As a consequence, miRNAs are intensely studied and literature on miRNAs has been constantly growing. While this growing body of literature reflects the interest in miRNAs, it generates a challenge to maintain an overview, and the comparison of miRNAs that may function across diverse disease fields is complex due to this large number of relevant publications. To address these challenges, we designed miRetrieve, an R package and web application that provides an overview on miRNAs. By text mining, miRetrieve can characterize and compare miRNAs within specific disease fields and across disease areas. This overview provides focus and facilitates the generation of new hypotheses. Here, we explain how miRetrieve works and how it is used. Furthermore, we demonstrate its applicability in an exemplary case study and discuss its advantages and disadvantages.

Therapeutic approaches targeting molecular signaling pathways common to diabetes, lung diseases and cancer

Diabetes mellitus (DM), is the most common metabolic disease and is characterized by sustained hyperglycemia. Accumulating evidences supports a strong association between DM and numerous lung diseases including chronic obstructive pulmonary disease (COPD), fibrosis, and lung cancer (LC). The global incidence of DM-associated lung disorders is rising and several ongoing studies, including clinical trials, aim to elucidate the molecular mechanisms linking DM with lung disorders, in particular LC. Several potential mechanisms, including hyperglycemia, hyperinsulinemia, glycation, inflammation, and hypoxia, are cited as plausible links between DM and LC. In addition, studies also propose a connection between the use of anti-diabetic medications and reduction in the incidence of LC. However, the exact cause for DM associated lung diseases especially LC is not clear and is an area under intense investigation. Herein, we review the biological links reported between DM and lung disorders with an emphasis on LC. Furthermore, we report common signaling pathways (eg: TGF-β, IL-6, HIF-1, PDGF) and miRNAs that are dysregulated in DM and LC and serve as molecular targets for therapy. Finally, we propose a nanomedicine based approach for delivering therapeutics (eg: IL-24 plasmid DNA, HuR siRNA) to disrupt signaling pathways common to DM and LC and thus potentially treat DM-associated LC. Finally, we conclude that the effective modulation of commonly regulated signaling pathways would help design novel therapeutic protocols for treating DM patients diagnosed with LC.

Metabolic Dysfunction Biomarkers as Predictors of Early Diabetes

During the pathophysiological course of type 2 diabetes (T2D), several metabolic imbalances occur. There is increasing evidence that metabolic dysfunction far precedes clinical manifestations. Thus, knowing and understanding metabolic imbalances is crucial to unraveling new strategies and molecules (biomarkers) for the early-stage prediction of the disease's non-clinical phase. Lifestyle interventions must be made with considerable involvement of clinicians, and it should be considered that not all patients will respond in the same manner. Individuals with a high risk of diabetic progression will present compensatory metabolic mechanisms, translated into metabolic biomarkers that will therefore show potential predictive value to differentiate between progressors/non-progressors in T2D. Specific novel biomarkers are being proposed to entrap prediabetes and target progressors to achieve better outcomes. This study provides a review of the latest relevant biomarkers in prediabetes. A search for articles published between 2011 and 2021 was conducted; duplicates were removed, and inclusion criteria were applied. From the 29 studies considered, a survey of the most cited (relevant) biomarkers was conducted and further discussed in the two main identified fields: metabolomics, and miRNA studies.

miRNAs as biomarkers for diagnosis of type 2 diabetes: A systematic review

BACKGROUND

This systematic review summarizes results of studies that evaluated the expression of microRNAs (miRs) in prediabetes or type 2 diabetes (T2D).

METHODS

The information was obtained from PubMed, EMBL-EBI, Wanfang, Trip Database, Lilacs, CINAHL, Human microRNA Disease Database (HMDD) v3.0, and Google. A qualitative synthesis of the results was performed and miRs frequency was graphically represented. From 1893 identified studies, only 55 fulfilled the inclusion criteria. These 55 studies analyzed miRs in T2D, and of them, 13 also described data of prediabetes.

RESULTS

In diabetics, 122 miRs were reported and 35 miRs for prediabetics. However, we identified that five miRs (-122-5p, 144-3p, 210, 375, and -126b) were reported more often in diabetics and four (144-3p, -192, 29a, and -30d) in prediabetics.

CONCLUSIONS

Circulating miRs could be used as biomarkers of T2D. However, it is necessary to validate these microRNAs in prospective and multicenter studies with different population subgroups, considering age, gender, and risk factors.

Expression Profiles of Circulating microRNAs in South African Type 2 Diabetic Individuals on Treatment

Aim: The influence of disease duration and anti-diabetic treatment on epigenetic processes has been described, with limited focus on interactions with microRNAs (miRNAs). miRNAs have been found to play key roles in the regulation of pathways associated with type 2 diabetes mellitus (T2DM), and expression patterns in response to treatment may further promote their use as therapeutic targets in T2DM and its associated complications. We therefore aimed to investigate the expressions of circulating miRNAs (miR-30a-5p, miR-1299, miR-182-5p, miR-30e-3p and miR-126-3p) in newly diagnosed and known diabetics on treatment, in South Africa.

Methods: A total of 1254 participants with an average age of 53.8years were included in the study and classified according to glycaemic status (974 normotolerant, 92 screen-detected diabetes and 188 known diabetes). Whole blood levels of miR-30a-5p, miR-1299, miR-182-5p, miR-30e-3p and miR-126-3p were quantitated using RT-qPCR. Expression analysis was performed and compared across groups.

Results: All miRNAs were significantly overexpressed in subjects with known diabetes when compared to normotolerant individuals, as well as known diabetics vs. screen-detected (p<0.001). Upon performing regression analysis, of all miRNAs, only miR-182-5p remained associated with the duration of the disease after adjustment for type of treatment (OR: 0.127, CI: 0.018–0.236, p=0.023).

Conclusion: Our findings revealed important associations and altered expression patterns of miR-30a-5p, miR-1299, miR-182-5p, miR-30e-3p and miR-126-3p in known diabetics on anti-diabetic treatment compared to newly diagnosed individuals. Additionally, miR-182-5p expression decreased with increasing duration of T2DM. Further studies are, however, recommended to shed light on the involvement of the miRNA in insulin signalling and glucose homeostasis, to endorse its use as a therapeutic target in DM and its associated complications.

The β Cell in Diabetes: Integrating Biomarkers With Functional Measures

The pathogenesis of hyperglycemia observed in most forms of diabetes is intimately tied to the islet β cell. Impairments in propeptide processing and secretory function, along with the loss of these vital cells, is demonstrable not only in those in whom the diagnosis is established but typically also in individuals who are at increased risk of developing the disease. Biomarkers are used to inform on the state of a biological process, pathological condition, or response to an intervention and are increasingly being used for predicting, diagnosing, and prognosticating disease. They are also proving to be of use in the different forms of diabetes in both research and clinical settings. This review focuses on the β cell, addressing the potential utility of genetic markers, circulating molecules, immune cell phenotyping, and imaging approaches as biomarkers of cellular function and loss of this critical cell. Further, we consider how these biomarkers complement the more long-established, dynamic, and often complex measurements of β-cell secretory function that themselves could be considered biomarkers.

MicroRNA and diabetic retinopathy-biomarkers and novel therapeutics

Diabetic retinopathy (DR) accounts for ~80% of legal blindness in persons aged 20-74 years and is associated with enormous social and health burdens. Current therapies are invasive, non-curative, and in-effective in 15-25% of DR patients. This review outlines the potential utility of microRNAs (miRNAs) as biomarkers and potential therapy for diabetic retinopathy. miRNAs are small noncoding forms of RNA that may play a role in the pathogenesis of DR by altering the level of expression of genes via single nucleotide polymorphism and regulatory loops. A majority of miRNAs are intracellular and specific intracellular microRNAs have been associated with cellular changes associated with DR. Some microRNAs are extracellular and called circulatory microRNAs. Circulatory miRNAs have been found to be differentially expressed in serum and bodily fluid in patients with diabetes mellitus (DM) with and without retinopathy. Some miRNAs have been associated with the severity of DR, and future studies may reveal whether circulatory miRNAs could serve as novel reliable biomarkers to detect or predict retinopathy progression. Therapeutic strategies can be developed utilizing the natural miRNA/long noncoding RNA (lncRNA) regulatory loops. miRNAs and lncRNAs are two major families of the non-protein-coding transcripts. They are regulatory molecules for fundamental cellular processes via a variety of mechanisms, and their expression and function are tightly regulated. The recent evidence indicates a cross-talk between miRNAs and lncRNAs. Therefore, dysregulation of miRNAs and lncRNAs is critical to human disease pathogenesis, such as diabetic retinopathy. miRNAs are long-distance communicators and reprogramming agents, and they embody an entirely novel paradigm in cellular and tissue signaling and interaction. By targeting specific miRNAs, whole pathways implicated in the pathogenesis of DR may potentially be altered. Understanding the endogenous roles of miRNAs in the pathogenesis of diabetic retinopathy could lead to novel diagnostic and therapeutic approaches to managing this frequently blinding retinal condition.