Extracellular RNAs Are Associated With Insulin Resistance and Metabolic Phenotypes

Epigenetic Programming and Fetal Metabolic Programming

Fetal metabolic programming caused by the adverse intrauterine environment can induce metabolic syndrome in adult offspring. Adverse intrauterine environment introduces fetal long-term relatively irreversible changes in organs and metabolism, and thus causes fetal metabolic programming leading metabolic syndrome in adult offspring. Fetal metabolic programming of obesity and insulin resistance plays a key role in this process. The mechanism of fetal metabolic programming is still not very clear. It is suggested that epigenetic programming, also induced by the adverse intrauterine environment, is a critical underlying mechanism of fetal metabolic programming. Fetal epigenetic programming affects gene expression changes and cellular function through epigenetic modifications without DNA nucleotide sequence changes. Epigenetic modifications can be relatively stably retained and transmitted through mitosis and generations, and thereby induce the development of metabolic syndrome in adult offspring. This manuscript provides an overview of the critical role of epigenetic programming in fetal metabolic programming.

The clinical potential of circulating microRNAs in obesity

Obesity is a complex condition that is characterized by excessive fat accumulation, which can lead to the development of metabolic disorders, such as type 2 diabetes mellitus, nonalcoholic fatty liver disease and cardiovascular diseases. Evidence is accumulating that circulating microRNAs (miRNAs) act as a new class of endocrine factor. These miRNAs are released by many types of tissue, including adipose tissues. miRNAs might serve as endocrine and paracrine messengers that facilitate communication between donor cells and tissues with receptor cells or target tissues, thereby potentially having important roles in metabolic organ crosstalk. Moreover, many miRNAs are closely associated with the differentiation of adipocytes and are dysregulated in obesity. As such, circulating miRNAs are attractive potential biomarkers and hold promise for the development of miRNA-based therapeutics (such as miRNA mimetics, anti-miRNA oligonucleotides and exosomes loaded with miRNA) for obesity and related disorders. Here we review the latest research progress on the roles of circulating miRNAs in metabolic organ crosstalk. In addition, we discuss the clinical potential of circulating miRNAs as feasible biomarkers for the assessment of future risk of metabolic disorders and as therapeutic targets in obesity and related diseases.

Circulating miRNAs as Biomarkers of Obesity and Obesity-Associated Comorbidities in Children and Adolescents: A Systematic Review

Early detection of obesity and its associated comorbidities in children needs priority for the development of effective therapeutic intervention. Circulating miRNAs (microRNAs) have been proposed as biomarkers for obesity and its comorbidities; therefore, we conducted a systematic review to summarize results of studies that have quantified the profile of miRNAs in children and adolescents with obesity and/or associated disorders. Nine studies aiming to examine differences in miRNA expression levels between children with normal weight and obesity or between obese children with or without cardiometabolic diseases were included in this review. We identified four miRNAs overexpressed in obesity (miR-222, miR-142-3, miR-140-5p, and miR-143) and two miRNAs (miR-122 and miR-34a) overexpressed in children with obesity and nonalcoholic fatty liver disease (NAFLD) and/or insulin resistance. In conclusion, circulating miRNAs are promising diagnostic biomarkers of obesity-associated diseases such as NAFLD and type 2 diabetes already in childhood. However, more studies in children, using massive search technology and with larger sample sizes, are required to draw any firm conclusions.

Associations of Circulating Extracellular RNAs With Myocardial Remodeling and Heart Failure

Importance

Mortality is high among patients heart failure (HF) who are receiving treatment, and therefore identifying new pathways rooted in preclinical cardiac remodeling phenotypes may afford novel biomarkers and therapeutic avenues. Circulating extracellular RNAs (ex-RNAs) are an emerging class of biomarkers with target-organ epigenetic effects relevant to myocardial biology, although large human investigations remain limited.

Objective

To measure the association of highly expressed circulating ex-RNAs with left ventricular remodeling and incident HF in a community-based cohort.

Design, Setting, and Participants

This is a prospective observational cohort study of individuals who were included in the eighth examination of the Framingham Offspring Cohort (2005-2008). Collected data include measurements of the left ventricle via electrocardiography, determination of circulating ex-RNAs in plasma, and incidence of heart failure. Data analysis was completed from December 2016 to June 2018.

Exposures

A total of 398 circulating ex-RNA molecules in plasma were measured by reverse transcription polymerase chain reaction; disease ontology analysis was also performed.

Main Outcomes and Measures

Echocardiographic indices of left ventricular (LV) remodeling and incident heart failure.

Results

A total of 2763 participants of the Framingham Heart Study with measured ex-RNAs (mean [SD] age, 66.3 [9.0] years; 1499 [54.3%] female) were included in this study. Of this sample, 2429 to 2432 individuals had echocardiographic measures recorded (depending on the measurement). A total of 2681 individuals had HF status determined, of whom 116 (4.3%) experienced HF (median [interquartile range] follow-up, 7.7 [6.6-8.6] years). We identified 12 ex-RNAs associated with LV mass and at least 1 other echocardiographic phenotype (LV end-diastolic volume or left atrial dimension). Of these 12 ex-RNAs, 3 micro RNAs (miR-17, miR-20a, and miR-106b) were associated with a 15% reduction in long-term incident HF per 2-fold increase in circulating level during the follow-up period, after adjustments for age, sex, established HF risk factors, and prevalent or interim myocardial infarction. These 3 RNAs shared sequence homology and targeted a shared group of messenger RNAs that specified pathways relevant to HF (eg, transforming growth factor-β signaling, growth/cell cycle, and apoptosis), and shared a disease association with hypertension in disease ontology analysis.

Conclusions and Relevance

This study identifies a group of circulating, noncoding RNAs associated with echocardiographic phenotypes, long-term incident HF, and pathways relevant to myocardial remodeling in a large community-based sample. Further investigations into the functional biology of these ex-RNAs are warranted for surveillance for HF prevention.

Pollen-derived RNAs Are Found in the Human Circulation

The presence of nonhuman RNAs in man has been questioned and it is unclear if food-derived miRNAs cross into the circulation. In a large population study, we found nonhuman miRNAs in plasma by RNA sequencing and validated a small number of pine-pollen miRNAs by RT-qPCR in 2,776 people. The presence of these pine-pollen miRNAs associated with hay fever and not with overt cardiovascular or pulmonary disease. Using in vivo and in vitro models, we found that transmission of pollen-miRNAs into the circulation occurs via pulmonary transfer and this transfer was mediated by platelet-pulmonary vascular cell interactions and platelet pollen-DNA uptake. These data demonstrate that pollen-derived plant miRNAs can be horizontally transferred into the circulation via the pulmonary system in humans. Although these data suggest mechanistic plausibility for pulmonary-mediated plant-derived miRNA transfer into the human circulation, our large observational cohort data do not implicate major disease or risk factor association.

[Correlation between serum microRNA-122 and insulin resistance in obese children]

OBJECTIVE

To study the relationship between serum microRNA-122 (miR-122) and insulin resistance in obese children.

METHODS

Forty-seven children with severely obesity aged 7-14 years and 45 age- and gender matched healthy children with normal weight (control group) were enrolled. The levels of height, weight, waistline, hip circumference, fasting blood glucose (FBG), fasting insulin (FINS), triglyceride (TG), total cholesterol (TC), free fatty acid (FFA), interleukin-6 (IL-6) and miR-122 in the two groups were measured. Body mass index (BMI), waist-hip ratio (WHR) and insulin resistance index (HOMA-IR) were calculated.

RESULTS

Compared with the control group, the height, weight, BMI, WHR, FINS, HOMA-IR, TG, FFA, IL-6, and miR-122 levels in the obese group were significantly increased (P<0.05). MiR-122 levels in the obese group were positively correlated with FINS, HOMA-IR and IL-6 levels (r=0.408, 0.442, and 0.464 respectively, P<0.05). The changes of miR-122 have a linear regression relationship with IL-6 (b'=0.318, P<0.05).

CONCLUSIONS

The elevated serum miR-122 levels may be correlated with insulin resistance in obese children. The mechanism needs to be further studied.

The role of microRNAs in the regulation of insulin signaling pathway with respect to metabolic and mitogenic cascades: A review

Insulin resistance (IR) is a shared pathological condition among type 2 diabetes, obesity, cardiovascular disease, and other metabolic disorders. It is growing significantly all over the world and consequently, a substantial effort is needed for developing the potential novel diagnostics and therapeutics. An insulin signaling pathway is tightly modulated by different mechanisms including the epigenetic modifications. Today, a deal of great attention has been shifted towards the regulatory role of noncoding RNAs on target proteins of the insulin signaling pathway. Noncoding RNAs are a major area of the epigenetics which control gene expression at the posttranscriptional levels and include a large class of microRNAs (miRNAs). With this in view, many studies have implicated the mediatory effects of miRNAs on the downstream metabolic and mitogenic proteins of the insulin signaling pathway. Since providing new biomarkers for the early diagnosis of IR and related metabolic traits are very significant, we intended to review the possible role of miRNAs in the regulation of the insulin signaling pathway, with a primary focus on the downstream target proteins of the metabolic and mitogenic cascades.

Circulating microRNAs in human obesity: a systematic review

Context: Differential expression profiles of microRNAs have been reported in human obesity suggesting a miRNAs role in the development of obesity and associated disorders. Objective: To review circulating microRNAs (c-miRNAs) dysregulated in human obesity and to predict their possible target genes. Methods: We performed a systematic review on PubMed database (PROSPERO, CRD42017077742) for original works on c-miRNAs and human obesity and recorded c-miRNAs with differential expression profiles. Potential target genes and metabolic pathways for dysregulated miRNAs with at least two independent reports were searched using bioinformatic tools. Results: Twenty-two c-miRNAs are overexpressed, nine underexpressed and two c-miRNAs dysregulated in both directions in people with obesity compared to lean controls. Bioinformatic analyses suggest these c-miRNAs target on genes associated with fatty acid metabolism and PI3k/Akt pathway. Conclusion: Literature records 33 c-miRNAs confirmedly dysregulated in human obesity. Their predicted target genes are involved in pathways that could explain the development of obesity and its comorbidities. Further research will clarify the role of these miRNAs on metabolic diseases and their usefulness for the prognosis, prevention and treatment of obesity.

Circulating RNAs as predictive markers for the progression of type 2 diabetes

Type 2 Diabetes Mellitus (T2DM) is the most prevalent form of diabetes in the USA, thus, the identification of biomarkers that could be used to predict the progression from prediabetes to T2DM would be greatly beneficial. Recently, circulating RNA including microRNAs (miRNAs) present in various body fluids have emerged as potential biomarkers for various health conditions, including T2DM. Whereas studies that examine the changes of miRNA spectra between healthy controls and T2DM individuals have been reported, the goal of this study is to conduct a baseline comparison of prediabetic individuals who either progress to T2DM, or remain prediabetic. Using an advanced small RNA sequencing library construction method that improves the detection of miRNA species, we identified 57 miRNAs that showed significant concentration differences between progressors (progress from prediabetes to T2DM) and non-progressors. Among them, 26 have been previously reported to be associated with T2DM in either body fluids or tissue samples. Some of the miRNAs identified were also affected by obesity. Furthermore, we identified miRNA panels that are able to discriminate progressors from non-progressors. These results suggest that upon further validation these miRNAs may be useful to predict the risk of conversion to T2DM from prediabetes.

Exosomes and diabetes

Diabetes is a group of metabolic diseases characterized by elevated blood glucose levels that drive the development of life-threatening complications. Diabetes results from a situation of insufficient insulin action, either by deficient production of the hormone by the pancreas, or by the development of insulin resistance in peripheral tissues such as liver, muscle, or the adipose depots. Communication between organs is thus central to the maintenance of glucose homoeostasis. Recently, several studies are evidencing that small vesicles called exosomes released by, amongst other, the adipose tissue can regulate gene expression in other tissues, hence modulating interorgan crosstalk. Therefore, exosomes participate in the development of diabetes and its associated complications. Their study holds the potential of providing us with novel biomarkers for the early diagnosis and stratification of patients at risk of developing diabetes, hence allowing the timely implementation of more personalized therapies. On the other hand, the molecular dissection of the pathways initiated by exosomes under situations of metabolic stress could help to gain a deeper knowledge of the pathophysiology of diabetes and its associated metabolic diseases.

Predicting and understanding the response to short-term intensive insulin therapy in people with early type 2 diabetes

OBJECTIVE

Short-term intensive insulin therapy (IIT) early in the course of type 2 diabetes acutely improves beta-cell function with long-lasting effects on glycemic control. However, conventional measures cannot determine which patients are better suited for IIT, and little is known about the molecular mechanisms determining response. Therefore, this study aimed to develop a model that could accurately predict the response to IIT and provide insight into molecular mechanisms driving such response in humans.

METHODS

Twenty-four patients with early type 2 diabetes were assessed at baseline and four weeks after IIT, consisting of basal detemir and premeal insulin aspart. Twelve individuals had a beneficial beta-cell response to IIT (responders) and 12 did not (nonresponders). Beta-cell function was assessed by multiple methods, including Insulin Secretion-Sensitivity Index-2. MicroRNAs (miRNAs) were profiled in plasma samples before and after IIT. The response to IIT was modeled using a machine learning algorithm and potential miRNA-mediated regulatory mechanisms assessed by differential expression, correlation, and functional network analyses (FNA).

RESULTS

Baseline levels of circulating miR-145-5p, miR-29c-3p, and HbA1c accurately (91.7%) predicted the response to IIT (OR = 121 [95% CI: 6.7, 2188.3]). Mechanistically, a previously described regulatory loop between miR-145-5p and miR-483-3p/5p, which controls TP53-mediated apoptosis, appears to also occur in our study population of humans with early type 2 diabetes. In addition, significant (fold change > 2, P < 0.05) longitudinal changes due to IIT in the circulating levels of miR-138-5p, miR-192-5p, miR-195-5p, miR-320b, and let-7a-5p further characterized the responder group and significantly correlated (|r| > 0.4, P < 0.05) with the changes in measures of beta-cell function and insulin sensitivity. FNA identified a network of coordinately/cooperatively regulated miRNA-targeted genes that potentially drives the IIT response through negative regulation of apoptotic processes that underlie beta cell dysfunction and concomitant positive regulation of proliferation.

CONCLUSIONS

Responses to IIT in people with early type 2 diabetes are associated with characteristic miRNA signatures. This study represents a first step to identify potential responders to IIT (a current limitation in the field) and provides important insight into the pathophysiologic determinants of the reversibility of beta-cell dysfunction. ClinicalTrial.gov identifier: NCT01270789.

Epigenetics and Common Non Communicable Disease

Common Non communicable diseases (NCDs), such as cardiovascular disease, cancer, schizophrenia, and diabetes, have become the major cause of death in the world. They result from an interaction between genetics, lifestyle and environmental factors. The prevalence of NCDs are increasing, and researchers hopes to find efficient strategies to predict, prevent and treat them. Given the role of epigenome in the etiology of NCDs, insight into epigenetic mechanisms may offer opportunities to predict, detect, and prevent disease long before its clinical onset.Epigenetic alterations are exerted through several mechanisms including: chromatin modification, DNA methylation and controlling gene expression by non-coding RNAs (ncRNAs). In this chapter, we will discuss about NCDs, with focus on cancer, diabetes and schizophrenia. Different epigenetic mechanisms, categorized into two main groups DNA methylation and chromatin modifications and non-coding RNAs, will be separately discussed for these NCDs.

Obesity-associated exosomal miRNAs modulate glucose and lipid metabolism in mice

Obesity is frequently associated with metabolic disease. Here, we show that obesity changes the miRNA profile of plasma exosomes in mice, including increases in miR-122, miR-192, miR-27a-3p, and miR-27b-3p Importantly, treatment of lean mice with exosomes isolated from obese mice induces glucose intolerance and insulin resistance. Moreover, administration of control exosomes transfected with obesity-associated miRNA mimics strongly induces glucose intolerance in lean mice and results in central obesity and hepatic steatosis. Expression of the candidate target gene Ppara is decreased in white adipose tissue but not in the liver of mimic-treated (MIMIC) mice, and this is accompanied by increased circulating free fatty acids and hypertriglyceridemia. Treatment with a specific siRNA targeting Ppara transfected into exosomes recapitulates the phenotype induced by obesity-associated miRNAs. Importantly, simultaneously reducing free fatty acid plasma levels in MIMIC mice with either the lipolysis inhibitor acipimox or the PPARα agonist fenofibrate partially protects against these metabolic alterations. Overall, our data highlight the central role of obesity-associated exosomal miRNAs in the etiopathogeny of glucose intolerance and dyslipidemia.

Obesity in Type 1 Diabetes: Pathophysiology, Clinical Impact, and Mechanisms

There has been an alarming increase in the prevalence of obesity in people with type 1 diabetes in recent years. Although obesity has long been recognized as a major risk factor for the development of type 2 diabetes and a catalyst for complications, much less is known about the role of obesity in the initiation and pathogenesis of type 1 diabetes. Emerging evidence suggests that obesity contributes to insulin resistance, dyslipidemia, and cardiometabolic complications in type 1 diabetes. Unique therapeutic strategies may be required to address these comorbidities within the context of intensive insulin therapy, which promotes weight gain. There is an urgent need for clinical guidelines for the prevention and management of obesity in type 1 diabetes. The development of these recommendations will require a transdisciplinary research strategy addressing metabolism, molecular mechanisms, lifestyle, neuropsychology, and novel therapeutics. In this review, the prevalence, clinical impact, energy balance physiology, and potential mechanisms of obesity in type 1 diabetes are described, with a special focus on the substantial gaps in knowledge in this field. Our goal is to provide a framework for the evidence base needed to develop type 1 diabetes-specific weight management recommendations that account for the competing outcomes of glycemic control and weight management.

Circulating microRNAs -192 and -194 are associated with the presence and incidence of diabetes mellitus

We sought to identify circulating microRNAs as biomarkers of prevalent or incident diabetes. In a pilot study of 18 sex- and age-matched patients with metabolic syndrome, nine of whom developed diabetes during 6 years of follow-up, an array of 372 microRNAs discovered significantly elevated serum levels of microRNAs -122, -192, -194, and -215 in patients who developed diabetes mellitus type 2 (T2DM). In two cross-sectional validation studies, one encompassing sex- and age-matched groups of patients with T2DM, impaired fasting glucose (IFG) and euglycemic controls (n = 43 each) and the other 53 patients with type 1 diabetes and 54 age- and BMI-matched euglycemic controls, serum levels of miR-192, miR-194, and mi215 were significantly higher in diabetic subjects than in probands with euglycemia or IFG. In a longitudinal study of 213 initially diabetes-free patients of whom 35 developed diabetes during 6 years of follow-up, elevated serum levels of microRNAs 192 and 194 were associated with incident T2DM, independently of fasting glucose, HbA1c and other risk factors. Serum levels of miR-192 and miR-194 were also elevated in diabetic Akt2 knockout mice compared to wild type mice. In conclusion, circulating microRNAs -192 and -194 are potential biomarkers for risk of diabetes.

Circulating miRNAs as Predictive Biomarkers of Type 2 Diabetes Mellitus Development in Coronary Heart Disease Patients from the CORDIOPREV Study

Circulating microRNAs (miRNAs) have been proposed as type 2 diabetes biomarkers, and they may be a more sensitive way to predict development of the disease than the currently used tools. Our aim was to identify whether circulating miRNAs, added to clinical and biochemical markers, yielded better potential for predicting type 2 diabetes. The study included 462 non-diabetic patients at baseline in the CORDIOPREV study. After a median follow-up of 60 months, 107 of them developed type 2 diabetes. Plasma levels of 24 miRNAs were measured at baseline by qRT-PCR, and other strong biomarkers to predict diabetes were determined. The ROC analysis identified 9 miRNAs, which, added to HbA1c, have a greater predictive value in early diagnosis of type 2 diabetes (AUC = 0.8342) than HbA1c alone (AUC = 0.6950). The miRNA and HbA1c-based model did not improve when the FINDRISC was included (AUC = 0.8293). Cox regression analyses showed that patients with low miR-103, miR-28-3p, miR-29a, and miR-9 and high miR-30a-5p and miR-150 circulating levels have a higher risk of disease (HR = 11.27; 95% CI = 2.61-48.65). Our results suggest that circulating miRNAs could potentially be used as a new tool for predicting the development of type 2 diabetes in clinical practice.

PIWI-like protein, HIWI2: A novel player in proliferative diabetic retinopathy

Diabetic retinopathy (DR) is one of the major causes of blindness resulting from prolonged hyperglycemia which leads to breakdown of blood retinal barrier and excessive neovascularization. In our previous study, we demonstrated the presence of germline-specific PIWI-like proteins in human retina and retinal pigment epithelium (RPE) and a discrete function of HIWI2 (PIWIL4) in the assembly of tight junction through Akt/GSK3α/β. Recently, PIWI/piRNA has been suggested to be involved in the development of diabetes. Here, we have investigated the role of HIWI2 in proliferative diabetic retinopathy (PDR). Interestingly, Western blot analysis indicated the elevated expression of HIWI2 in vitreous aspirates of patients with PDR in comparison to macular hole (MH) and rhegmatogenous retinal detachment (RRD). In addition, treatment of ARPE19 with 25% of PDR vitreous aspirate significantly increased the expression of HIWI2. Moreover, exposure of ARPE19 to oxidative stress and VEGF, induced the expression of HIWI2. Further, we knocked down HIWI2 in ARPE19 cells to understand its role in the disease progression. Silencing HIWI2 reduced the expression of growth factors, VEGF and TGFβ1, and altered the expression of epithelial to mesenchymal transition (EMT) markers E-cadherin and αSMA. In addition, expression of MMP9 and cell migration was reduced in Si-HIWI2. Collectively, our report highlights a novel function and association of a piRNA binding protein, HIWI2 to PDR. The elevated expression of HIWI2 in PDR could influence various aspects of the disease pathogenesis, like EMT changes and cell migration. Hence, understanding the exact function of HIWI2 in retina could reveal its potential as a therapeutic target for retinopathy.

Relationship of Circulating miRNAs with Insulin Sensitivity and Associated Metabolic Risk Factors in Humans

BACKGROUND

Insulin resistance disrupts metabolic processes and leads to various chronic disease states such as diabetes and metabolic syndrome (MetS). However, the mechanism linking insulin resistance with cardiometabolic disease pathophysiology is still unclear. One possibility may be through circulating microRNAs (c-miRs), which can alter gene expression in target tissues. Our goal was to assess the relationship of c-miRs with insulin sensitivity, as measured by the gold standard, hyperinsulinemic-euglycemic clamp technique.

METHODS

Eighty-one nondiabetic, sedentary, and weight-stable patients across a wide range of insulin sensitivities were studied. Measurements were taken for blood pressure, anthropometric data, fasting glucose and lipids, and insulin sensitivity measured by clamp. After an initial screening array to identify candidate miRs in plasma, all samples were assessed for relationships between these c-miRs and insulin sensitivity, as well as associated metabolic factors.

RESULTS

miR-16 and miR-107 were positively associated with insulin sensitivity (R2 = 0.09, P = 0.0074 and R2 = 0.08, P = 0.0417, respectively) and remained so after adjustment with body mass index (BMI). After adjusting for BMI, miR-33, -150, and -222 were additionally found to be related to insulin sensitivity. Regarding metabolic risk factors, miR-16 was associated with waist circumference (r = -0.25), triglycerides (r = -0.28), and high-density lipoprotein (r = 0.22), while miR-33 was inversely associated with systolic blood pressure (r = -0.29). No significant relationships were found between any candidate c-miRs and BMI, diastolic blood pressure, or fasting glucose.

CONCLUSIONS

Our results show that relative levels of circulating miR-16, -107, -33, -150, and -222 are associated with insulin sensitivity and metabolic risk factors, and suggest that multiple miRs may act in concert to produce insulin resistance and the clustering of associated traits that comprise the MetS. Therefore, miRs may have potential as novel therapeutic targets or agents in cardiometabolic disease.

Regulation of insulin resistance and type II diabetes by hepatitis C virus infection: A driver function of circulating miRNAs

Hepatitis C virus (HCV) infection is a serious worldwide healthcare issue. Its association with various liver diseases including hepatocellular carcinoma (HCC) is well studied. However, the study on the relationship between HCV infection and the development of insulin resistance and diabetes is very limited. Current research has already elucidated some underlying mechanisms, especially on the regulation of metabolism and insulin signalling by viral proteins. More studies have emerged recently on the correlation between HCV infection‐derived miRNAs and diabetes and insulin resistance. However, no studies have been carried out to directly address if these miRNAs, especially circulating miRNAs, have causal effects on the development of insulin resistance and diabetes. Here, we proposed a new perspective that circulating miRNAs can perform regulatory functions to modulate gene expression in peripheral tissues leading to insulin resistance and diabetes, rather than just a passive factor associated with these pathological processes. The detailed rationales were elaborated through comprehensive literature review and bioinformatic analyses. miR‐122 was identified to be one of the most potential circulating miRNAs to cause insulin resistance. This result along with the idea about the driver function of circulating miRNAs will promote further investigations that eventually lead to the development of novel strategies to treat HCV infection‐associated extrahepatic comorbidities.

Lower Circulating miR-122 Level in Patients with HNF1A Variant-Induced Diabetes Compared with Type 2 Diabetes

miR-122, the expression of which is regulated by several transcription factors, such as HNF1A, was recently reported to be associated with type 2 diabetes (T2DM) and hepatocellular carcinoma. HNF1A variants can cause diabetes and might be involved in the development of primary liver neoplasm. Differences in miR-122 expression among different types of diabetes have not been studied. This study aimed to investigate differences in serum miR-122 levels in Chinese patients with different forms of diabetes, including T2DM, type 1 diabetes (T1DM), HNF1A variant-induced diabetes (HNF1A-DM), glucokinase variant-induced diabetes (GCK-DM), and mitochondrial A3243G mutation-induced diabetes (MDM). In total, 12 HNF1A-DM patients, 24 gender-, age-, and body mass index-matched (1 : 2) T2DM patients and 24 healthy subjects were included in this study. In addition, 30 monogenic diabetes (11 GCK-DM and 19 MDM) and 17 T1DM patients were included. Fasted blood biochemistry and miR-122 were measured. The results showed that the HNF1A-DM patients had lower miR-122 levels [0.046 (0.023, 0.121)] than T2DM patients [0.165 (0.036, 0.939), P = 0.02] and healthy controls [0.249 (0.049, 1.234), P = 0.019]. The area under the curve of the receiver operating characteristic curve for miR-122 to discriminate HNF1A-DM and T2DM was 0.687 (95% CI: 0.52-0.86, P = 0.07). There was no difference in serum miR-122 among HNF1A-DM, GCK-DM, MDM, and T1DM patients. Lower serum miR-122 is a unique feature of HNF1A-DM patients and might partially explain the increased risk for liver neoplasm and abnormal lipid metabolism in HNF1A-DM patients.

Change in circulating microRNA profile of obese children indicates future risk of adult diabetes

PURPOSE

Childhood obesity increases susceptibility to type 2 diabetes (T2D) in adults. Circulating microRNAs (miRNAs) in serum have been proposed as potential diagnostic biomarkers, and they may contribute to the progression toward T2D. Here, we investigated the possibility of predicting the future risk of adult T2D in obese children by using circulating miRNAs.

BASIC PROCEDURES

We performed miRNA high-throughput sequencing to screen relevant circulating miRNAs in obese children. The expression patterns of targeted miRNAs were further explored in obese children and adults with T2D. To investigate the underlying contributions of these miRNAs to the development of T2D, we detected the impacts of the candidate miRNAs on preadipocyte proliferation, insulin secretion by pancreatic β-cell, and glucose uptake by skeletal muscle cells.

MAIN FINDINGS

Three miRNAs (miR-486, miR-146b and miR-15b), whose expression in the circulation was most dramatically augmented in obese children and adult T2D patients, were selected for further investigation. Of these 3 miRNAs, miR-486 was implicated in accelerating preadipocyte proliferation and myotube glucose intolerance, miR-146b and miR-15b were engaged in the suppression of high concentration glucose-induced pancreatic insulin secretion, and they all contributed to the pathological processes of obesity and T2D.

PRINCIPAL CONCLUSIONS

Our results provide a better understanding of the role of circulating miRNAs, particularly miR-486, miR-146b and miR-15b, in predicting the future risk of T2D in obese children.

Personalized epigenetic management of diabetes

The novel genome-wide assays of epigenetic marks have resulted in a greater understanding of how genetics and the environment interact in the development and inheritance of diabetes. Chronic hyperglycemia induces epigenetic changes in multiple organs, contributing to diabetic complications. Specific epigenetic-modifying compounds have been developed to erase these modifications, possibly slowing down the onset of diabetes-related complications. The current review is an update of the previously published paper, describing the most recent advances in the epigenetics of diabetes.

Neurite Outgrowth Inhibitor B Receptor: A Versatile Receptor with Multiple Functions and Actions

Members of the reticulon protein family are predominantly distributed within the endoplasmic reticulum. The neurite outgrowth inhibitor (Nogo) has three subtypes, including Nogo-A (200 kDa), Nogo-B (55 kDa), and Nogo-C (25 kDa). Nogo-A and Nogo-C are potent Nogos that are predominantly expressed in the central nervous system. Nogo-B, the splice variant of reticulon-4, is expressed widely in multiple human organ systems, including the liver, lung, kidney, blood vessels, and inflammatory cells. Moreover, the Nogo-B receptor (NgBR) can interact with Nogo-B and can independently affect nervous system regeneration, the chemotaxis of endothelial cells, proliferation, and apoptosis. In recent years, it has been demonstrated that NgBR plays an important role in human pathophysiological processes, including lipid metabolism, angiogenesis, N-glycosylation, cell apoptosis, chemoresistance in human hepatocellular carcinoma, and epithelial-mesenchymal transition. The pathophysiologic effects of NgBR have garnered increased attention, and the detection and enhancement of NgBR expression may be a novel approach to monitor the development and to improve the prognosis of relevant human clinical diseases.