Down-regulation of MicroRNA-592 in obesity contributes to hyperglycemia and insulin resistance

Metabolic and microbial mechanisms related to the effects of dietary wheat levels on intramuscular fat content in finishing pigs

The current study aimed to investigate the metabolic and microbial mechanisms behind the effects of dietary wheat levels on intramuscular fat (IMF) content in the psoas major muscle (PM) of finishing pigs. Thirty-six barrows were arbitrarily assigned to two groups and fed with diets containing 25% or 55% wheat. Enhancing dietary wheat levels led to low energy states, resulting in reduced IMF content. This coincided with reduced serum glucose and low-density lipoprotein cholesterol levels. The AMP-activated protein kinase α2/sirtuin 1/peroxisome proliferator-activated receptor-γ coactivator 1α pathway may be activated by high-wheat diets, causing downregulation of adipogenesis and lipogenesis genes, and upregulation of lipolysis and gluconeogenesis genes. High-wheat diets decreased relative abundance of Lactobacillus and Coprococcus, whereas increased SMB53 proportion, subsequently decreasing colonic propionate content. Microbial glycolysis/gluconeogenesis, d-glutamine and D-glutamate metabolism, flagellar assembly, and caprolactam degradation were linked to IMF content. Metabolomic analysis indicated that enhancing dietary wheat levels promoted the protein digestion and absorption and affected amino acids and lipid metabolism. Enhancing dietary wheat levels reduced serum glucose and colonic propionate content, coupled with strengthened amino acid metabolism, contributing to the low energy states. Furthermore, alterations in microbial composition and propionate resulted from high-wheat diets were associated with primary bile acid biosynthesis, arachidonic acid metabolism, steroid hormone biosynthesis, and biosynthesis of unsaturated fatty acids, as well as IMF content. Colonic microbiota played a role in reducing IMF content through modulating the propionate-mediated peroxisome proliferators-activated receptor signaling pathway. In conclusion, body energy and gut microbiota balance collectively influenced lipid metabolism.

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.

FOXO1 regulates RUNX2 ubiquitination through SMURF2 in calcific aortic valve disease

The prevalence of calcific aortic valve disease (CAVD) remains substantial while there is currently no medical therapy available. Forkhead box O1 (FOXO1) is known to be involved in the pathogenesis of cardiovascular diseases, including vascular calcification and atherosclerosis; however, its specific role in calcific aortic valve disease remains to be elucidated. In this study, we identified FOXO1 significantly down-regulated in the aortic valve interstitial cells (VICs) of calcified aortic valves by investigating clinical specimens and GEO database analysis. FOXO1 silencing or inhibition promoted VICs osteogenic differentiation in vitro and aortic valve calcification in Apoe-/- mice, respectively. We identified that FOXO1 facilitated the ubiquitination and degradation of RUNX2, which process was mainly mediated by SMAD-specific E3 ubiquitin ligase 2 (SMURF2). Our discoveries unveil a heretofore unacknowledged mechanism involving the FOXO1/SMURF2/RUNX2 axis in CAVD, thereby proposing the potential therapeutic utility of FOXO1 or SMURF2 as viable strategies to impede the progression of CAVD.

MicroRNA-34a Mediates High-Fat-Induced Hepatic Insulin Resistance by Targeting ENO3

The etiology of numerous metabolic disorders is characterized by hepatic insulin resistance (IR). Uncertainty surrounds miR-34a's contribution to high-fat-induced hepatic IR and its probable mechanism. The role and mechanism of miR-34a and its target gene ENO3 in high-fat-induced hepatic IR were explored by overexpressing/suppressing miR-34a and ENO3 levels in in vivo and in vitro experiments. Moreover, as a human hepatic IR model, the miR-34a/ENO3 pathway was validated in patients with non-alcoholic fatty liver disease (NAFLD). The overexpression of hepatic miR-34a lowered insulin signaling and altered glucose metabolism in hepatocytes. In contrast, reducing miR-34a expression significantly reversed hepatic IR indices induced by palmitic acid (PA)/HFD. ENO3 was identified as a direct target gene of miR-34a. Overexpression of ENO3 effectively inhibited high-fat-induced hepatic IR-related indices both in vitro and in vivo. Moreover, the expression patterns of members of the miR-34a/ENO3 pathway in the liver tissues of NAFLD patients was in line with the findings of both cellular and animal studies. A high-fat-induced increase in hepatic miR-34a levels attenuates insulin signaling and impairs glucose metabolism by suppressing the expression of its target gene ENO3, ultimately leading to hepatic IR. The miR-34a/ENO3 pathway may be a potential therapeutic target for hepatic IR and related metabolic diseases.

Biomarkers of obesity-mediated insulin resistance: focus on microRNAs

Obesity and metabolic syndromes are becoming increasingly prevalent worldwide. Insulin resistance (IR) is a common complication of obesity. However, IR occurrence varies across individuals with obesity and may involve epigenetic factors. To rationalize the allocation of healthcare resources, biomarkers for the early risk stratification of individuals with obesity should be identified. MicroRNAs (miRNAs) are closely associated with metabolic diseases and involved in epigenetic regulation. In this review, we have summarized the changes in miRNA expression in the peripheral circulation and tissues of patients and animals with obesity-associated IR over the last 5 years and identified several candidate biomarkers that predict obesity-related IR. There are areas for improvement in existing studies. First, more than the predictive validity of a single biomarker is required, and a biomarker panel needs to be formed. Second, miRNAs are often studied in isolation and do not form a network of signaling pathways. We believe that early biomarkers can help clinicians accurately predict individuals prone to obesity-related IR at an early stage. Epigenetic regulation may be one of the underlying causes of different clinical outcomes in individuals with obesity. Future studies should focus on objectively reflecting the differences in miRNA profile expression in individuals with obesity-related IR, which may help identify more reliable biomarkers. Understanding the metabolic pathways of these miRNAs can help design new metabolic risk prevention and management strategies, and support the development of drugs to treat obesity and metabolic disorders.

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.

Glycemia-Induced miRNA Changes: A Review

Diabetes is a rapidly increasing global health concern that significantly strains the health system due to its downstream complications. Dysregulation in glycemia represents one of the fundamental obstacles to achieving glycemic control in diabetic patients. Frequent hyperglycemia and/or hypoglycemia events contribute to pathologies that disrupt cellular and metabolic processes, which may contribute to the development of macrovascular and microvascular complications, worsening the disease burden and mortality. miRNAs are small single-stranded non-coding RNAs that regulate cellular protein expression and have been linked to various diseases, including diabetes mellitus. miRNAs have proven useful in the diagnosis, treatment, and prognosis of diabetes and its complications. There is a vast body of literature examining the role of miRNA biomarkers in diabetes, aiming for earlier diagnoses and improved treatment for diabetic patients. This article reviews the most recent literature discussing the role of specific miRNAs in glycemic control, platelet activity, and macrovascular and microvascular complications. Our review examines the different miRNAs involved in the pathological processes leading to the development of type 2 diabetes mellitus, such as endothelial dysfunction, pancreatic beta-cell dysfunction, and insulin resistance. Furthermore, we discuss the potential applications of miRNAs as next-generation biomarkers in diabetes with the aim of preventing, treating, and reversing diabetes.

PCR Techniques and Their Clinical Applications

Kary B. Mullis developed a revolutionary method name polymerase chain reaction (PCR) in 1983, which can synthesize new strand of DNA complementary to the template strand of DNA and produce billions of copies of a DNA fragment only in few hours. Denaturation, annealing, and extension are the three primary steps involved in the PCR process, which generally requires thermocyclers, DNA template, a pair of primers, Taq polymerase, nucleotides, buffers, etc. With the development of PCR, from traditional PCR, quantitative PCR, to next digital PCR, PCR has become a powerful tool in life sciences and medicine. Applications of PCR techniques for infectious diseases include specific or broad-spectrum pathogen detection, assessment and surveillance of emerging infections, early detection of biological threat agents, and antimicrobial resistance analysis. Applications of PCR techniques for genetic diseases include prenatal diagnosis and screening of neonatal genetic diseases. Applications of PCR techniques for cancer research include tumor-related gene detection. This chapter aimed to discuss about the different types of PCR techniques, including traditional PCR, quantitative PCR, digital PCR, etc., and their applications for rapid detection, mutation screen or diagnosis in infectious diseases, inherited diseases, cancer, and other diseases.

Role of non-coding RNAs on liver metabolism and NAFLD pathogenesis

Obesity and type 2 diabetes are major contributors to the growing prevalence of non-alcoholic fatty liver disease (NAFLD), a chronic liver condition characterized by accumulation of fat in individuals without a significant amount of alcohol intake. The NAFLD spectrum ranges from simple steatosis (early stages, known as NAFL), to non-alcoholic steatohepatitis (NASH), which can progress to fibrosis and cirrhosis or hepatocellular carcinoma. Obesity, type 2 diabetes, and NAFLD are strongly associated with insulin resistance. In the liver, insulin resistance increases hepatic glucose output, lipogenesis, and VLDL secretion, leading to a combination of hyperglycemia and hypertriglyceridemia. Aberrant gene expression is a hallmark of insulin resistance. Non-coding RNAs (ncRNAs) have emerged as prominent regulators of gene expression that operate at the transcriptional, post-transcriptional, and post-translational levels. In the last couple of decades a wealth of studies have provided evidence that most processes of liver metabolism are orchestrated by ncRNAs. This review focuses on the role of microRNAs, long non-coding RNAs and circular RNAs as coordinators of hepatic function, as well as the current understanding on how their dysregulation contributes to abnormal metabolism and pathophysiology in animal models of insulin resistance and NAFLD. Moreover, ncRNAs are emerging as useful biomarkers that may be able to discriminate between the different stages of NAFLD. The potential of ncRNAs as therapeutic drugs for NAFLD treatment and as biomarkers is discussed.

Loss of neurodevelopmental-associated miR-592 impairs neurogenesis and causes social interaction deficits

microRNA-592 (miR-592) has been linked to neurogenesis, but the influence of miR-592 knockout in vivo remains unknown. Here, we report that miR-592 knockout represses IPC-to-mature neuron transition, impairs motor coordination and reduces social interaction. Combining the RNA-seq and tandem mass tagging-based quantitative proteomics analysis (TMT protein quantification) and luciferase reporter assays, we identified MeCP2 as the direct targetgene of miR-592 in the mouse cortex. In Tg(MECP2) mice, lipofection of miR-592 efficiently reduced MECP2 expression in the brains of Tg(MECP2) mice at E14.5. Furthermore, treatment with miR-592 partially ameliorated the autism-like phenotypes observed in adult Tg(MECP2) mice. The findings demonstrate that miR-592 might play a novel role in treating the neurodevelopmental-associated disorder.

Long non-coding RNA MEG3 inhibits neovascularization in diabetic retinopathy by regulating microRNA miR-6720-5p and cytochrome B5 reductase 2

Diabetic retinopathy (DR) is a major cause of vision loss in working and elderly populations. long non-coding RNA (LncRNA) MEG3 is thought to have some effect on DR, but the exact mechanism remains to be clarified. The expression levels of lncRNA MEG3, miR-6720-5p, and cytochrome B5 reductase 2 (CYB5R2) in human retinal microvascular endothelial cells (hRMECs) were detected by quantitative reverse transcription polymerase chain reaction (qRT-PCR). 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), transwell migration, and tube formation assays were used to determine the cell viability, migration, and tube formation ability of hRMECs, respectively. The interaction of MEG3, miR-6720-5p, and CYB5R2 was detected and explored by a luciferase assay. The expression of MEG3 and CYB5R2 was upregulated and that of miR-6720-5p was downregulated in patients with DR and hRMECs treated with high glucose. Knocking down MEG3 or CYB5R2 promoted proliferation, migration, and neovascularization in hRMECs. The intervention of miR-6720-5p reversed the effect of MEG3 knockdown on hRMEC function, and this effect was eliminated by silencing CYB5R2. Therefore, MEG3 acted as a sponge to suppress miR-6720-5p and regulate the expression of CYB5R2, thereby inhibiting DR neovascularization.

Circular RNAs; powerful microRNA sponges to overcome diabetic nephropathy

Diabetic nephropathy (DN), also known as diabetic kidney disease (DKD), is a drastic renal complication of type 1 and type 2 diabetes mellitus (DM). Poorly controlled DM over the years, may disrupt kidneys' blood vessels, leading to the hypertension (HTN) and DN onset. During DN, kidneys' waste filtering ability becomes disturbed. Being on a healthy lifestyle and controlling both DM and HTN are now the best proceedings to prevent or at least delay DN occurrence. Unfortunately, about one-fourth of diabetic individuals eventually experience the corresponding renal failure, and thus it is critical to discover effective diagnostic biomarkers and therapeutic strategies to combat DN. In the past few years, circular RNAs (circRNAs), as covalently closed endogenous non-coding RNAs (ncRNAs), are believed to affect DN pathogenesis in a positive manner. CircRNAs are able to impact different cellular processes and signaling pathways by targeting biological molecules or various molecular mechanisms. Still, as a key regulatory axis, circRNAs can select miRNAs as their molecular targets, in which they are considered as miRNA sponges. In this way, circRNA-induced suppression of particular miRNAs may prevent from DN progression or promotes the DN elimination. Since the expression of circRNAs has also been reported to be increased in DN-associated cells and tissues, they can be employed as either diagnostic biomarkers or therapeutic targets.

A combined microRNA and target protein-based panel for predicting the probability and severity of uraemic vascular calcification: a translational study

AIMS

Vascular calcification (VC) increases the future risk of cardiovascular events in uraemic patients, but effective therapies are still unavailable. Accurate identification of those at risk of developing VC using pathogenesis-based biomarkers is of particular interest and may facilitate individualized risk stratification. We aimed to uncover microRNA (miRNA)-target protein-based biomarker panels for evaluating uraemic VC probability and severity.

METHODS AND RESULTS

We created a three-tiered in vitro VC model and an in vivo uraemic rat model receiving high phosphate diet to mimic uraemic VC. RNAs from the three-tiered in vitro and in vivo uraemic VC models underwent miRNA and mRNA microarray, with results screened for differentially expressed miRNAs and their target genes as biomarkers. Findings were validated in original models and additionally in an ex vivo VC model and human cells, followed by functional assays of identified miRNAs and target proteins, and tests of sera from end-stage renal disease (ESRD) and non-dialysis-dependent chronic kidney disease (CKD) patients without and with VC. Totally 122 down-regulated and 119 up-regulated miRNAs during calcification progression were identified initially; further list narrowing based on miRNA-mRNA pairing, anti-correlation, and functional enrichment left 16 and 14 differentially expressed miRNAs and mRNAs. Levels of four miRNAs (miR-10b-5p, miR-195, miR-125b-2-3p, and miR-378a-3p) were shown to decrease throughout all models tested, while one mRNA (SULF1, a potential target of miR-378a-3p) exhibited the opposite trend concurrently. Among 96 ESRD (70.8% with VC) and 59 CKD patients (61% with VC), serum miR-125b2-3p and miR-378a-3p decreased with greater VC severity, while serum SULF1 levels increased. Adding serum miR-125b-2-3p, miR-378a-3p, and SULF1 into regression models for VC substantially improved performance compared to using clinical variables alone.

CONCLUSION

Using a translational approach, we discovered a novel panel of biomarkers for gauging the probability/severity of uraemic VC based on miRNAs/target proteins, which improved the diagnostic accuracy.

DeepGP: An Integrated Deep Learning Method for Endocrine Disease Gene Prediction Using Omics Data

Endocrinology is the study focusing on hormones and their actions. Hormones are known as chemical messengers, released into the blood, that exert functions through receptors to make an influence in the target cell. The capacity of the mammalian organism to perform as a whole unit is made possible based on two principal control mechanisms, the nervous system and the endocrine system. The endocrine system is essential in regulating growth and development, tissue function, metabolism, and reproductive processes. Endocrine diseases such as diabetes mellitus, Grave's disease, polycystic ovary syndrome, and insulin-like growth factor I deficiency (IGFI deficiency) are classical endocrine diseases. Endocrine dysfunction is also an increasing factor of morbidity in cancer and other dangerous diseases in humans. Thus, it is essential to understand the diseases from their genetic level in order to recognize more pathogenic genes and make a great effort in understanding the pathologies of endocrine diseases. In this study, we proposed a deep learning method named DeepGP based on graph convolutional network and convolutional neural network for prioritizing susceptible genes of five endocrine diseases. To test the performance of our method, we performed 10-cross-validations on an integrated reported dataset; DeepGP obtained a performance of the area under the curve of ∼83% and area under the precision-recall curve of ∼65%. We found that type 1 diabetes mellitus (T1DM) and type 2 diabetes mellitus (T2DM) share most of their associated genes; therefore, we should pay more attention to the rest of the genes related to T1DM and T2DM, respectively, which could help in understanding the pathogenesis and pathologies of these diseases.

Circular RNAs in metabolism and metabolic disorders

Metabolic syndrome (MetS) is a serious health condition triggered by hyperglycemia, dyslipidemia, and abnormal adipose deposition. Recently, circular RNAs (circRNAs) have been proposed as key molecular players in metabolic homeostasis due to their regulatory effects on genes linked to the modulation of multiple aspects of metabolism, including glucose and lipid homeostasis. Dysregulation of circRNAs can lead to metabolic disorders, indicating that circRNAs represent plausible potential targets to alleviate metabolic abnormalities. More recently, a series of circulating circRNAs have been identified to act as both essential regulatory molecules and biomarkers for the progression of metabolism-related disorders, including type 2 diabetes mellitus (T2DM or T2D) and cardiovascular disease (CVD). The findings of this study highlight the function of circRNAs in signaling pathways implicated in metabolic diseases and their potential as future therapeutics and disease biomarkers.

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

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

Epigenetic Remodeling in Obesity-Related Vascular Disease

Significance: The prevalence of obesity and cardiometabolic phenotypes is alarmingly increasing across the globe and is associated with atherosclerotic vascular complications and high mortality. In spite of multifactorial interventions, vascular residual risk remains high in this patient population, suggesting the need for breakthrough therapies. The mechanisms underpinning obesity-related vascular disease remain elusive and represent an intense area of investigation. Recent Advances: Epigenetic modifications-defined as environmentally induced chemical changes of DNA and histones that do not affect DNA sequence-are emerging as a potent modulator of gene transcription in the vasculature and might significantly contribute to the development of obesity-induced endothelial dysfunction. DNA methylation and histone post-translational modifications cooperate to build complex epigenetic signals, altering transcriptional networks that are implicated in redox homeostasis, mitochondrial function, vascular inflammation, and perivascular fat homeostasis in patients with cardiometabolic disturbances. Critical Issues: Deciphering the epigenetic landscape in the vasculature is extremely challenging due to the complexity of epigenetic signals and their function in regulating transcription. An overview of the most important epigenetic pathways is required to identify potential molecular targets to treat or prevent obesity-related endothelial dysfunction and atherosclerotic disease. This would enable the employment of precision medicine approaches in this setting. Future Directions: Current and future research efforts in this field entail a better definition of the vascular epigenome in obese patients as well as the unveiling of novel, cell-specific chromatin-modifying drugs that are able to erase specific epigenetic signals that are responsible for maladaptive transcriptional alterations and vascular dysfunction in obese patients. Antioxid. Redox Signal. 34, 1165-1199.

Cellular and Molecular Players in the Interplay between Adipose Tissue and Breast Cancer

The incidence and severity of obesity are rising in most of the world. In addition to metabolic disorders, obesity is associated with an increase in the incidence and severity of a variety of types of cancer, including breast cancer (BC). The bidirectional interaction between BC and adipose cells has been deeply investigated, although the molecular and cellular players involved in these mechanisms are far from being fully elucidated. Here, we review the current knowledge on these interactions and describe how preclinical research might be used to clarify the effects of obesity over BC progression and morbidity, with particular attention paid to promising therapeutic interventions.

Regulatory Effect of miR497-5p-CCNE1 Axis in Triple-Negative Breast Cancer Cells and Its Predictive Value for Early Diagnosis

OBJECTIVE

To explore the regulatory role of miR497-5p-CCNE1 axis in triple-negative breast cancer (TNBC) cells and its predictive value for early diagnosis.

METHODS

Cancer tissue and adjacent tissue samples were collected from 86 patients with TNBC.RT-PCR was used to detect the expression of miR497-5p and CCNE1 (target gene) mRNA, determined by biological prediction in tissue and TNBC cells. ROC was used to analyze the diagnostic value of miR497-5p in TNBC. MTT, invasion, and flow cytometry were used to detect the proliferation, invasion, cycle, apoptosis rate, and expression of related proteins of TNBC cells with overexpression of miR497-5p or knockdown of CCNE1.

RESULTS

RT-qPCR results showed that miR497-5p levels were significantly downregulated in TNBC tissue and cells, while CCNE1 expression was significantly upregulated, and miR497-5p expression was negatively correlated with that of CCNE1 (P<0.001). ROC analysis showed that the AUC of miR497-5p for TNBC was >0.9, which had better diagnostic value. The cell tests revealed that miR497-5p played a role in tumor inhibition, including inhibiting proliferation and invasion of TNBC cells, blocking the cell cycle, and promoting apoptosis. Bioinformatic prediction and subsequent experiments revealed that CCNE1 was the direct target of miR497-5p. Furthermore, after knocking down the expression of CCNE1 in TNBC cells, the proliferation and invasion of TNBC cells were significantly inhibited, the cell cycle blocked, and the apoptosis rate significantly increased (P<0.001), and expression of the proapoptosis-related proteins Bax and caspase 3 (cleaved) were upregulated, while expression of the antiapoptosis-related protein BCL2 was downregulated (P<0.001).

CONCLUSION

miR497-5p inhibited the proliferation and invasion of TNBC cells by targeting CCNE1, blocked the cell cycle and promoted the apoptosis of TNBC cells, and had better diagnostic value for TNBC. miR497-5p can be used as a new potential target for the treatment of TNBC.

The expression profile and role of non-coding RNAs in obesity

Latest years have experienced a dramatic upsurge in the knowledge about the function of non-coding transcripts in the determination of diverse human phenotypes including obesity. Several miRNAs and lncRNAs participate in the regulation of metabolic pathways leading to obesity. Several lncRNAs such as Mist, lincIRS2, lncRNA-p5549, H19, GAS5 and SNHG9 have been shown to be down-regulated in adipose tissues or other biological samples in the obese human or animal subjects. On the other hand, Meg3, Plnc1, Blnc1, AC092834.1, TINCR and PVT1 are among up-regulated lncRNAs in the obese subjects. Tens of miRNAs have differential expression between obese and non-obese subjects or between mature adipocytes and pre-adipocytes. Understanding the molecular mechanism of involvement of non-coding RNAs in the pathobiology of obesity would simplify design of therapeutic choices for protecting against obesity and its related comorbidities. We explain the available literature on the function of these transcripts in the pathobiology of obesity.

The Role of microRNAs in Metabolic Syndrome-Related Oxidative Stress

Oxidative stress (OxS) is the cause and the consequence of metabolic syndrome (MetS), the incidence and economic burden of which is increasing each year. OxS triggers the dysregulation of signaling pathways associated with metabolism and epigenetics, including microRNAs, which are biomarkers of metabolic disorders. In this review, we aimed to summarize the current knowledge regarding the interplay between microRNAs and OxS in MetS and its components. We searched PubMed and Google Scholar to summarize the most relevant studies. Collected data suggested that different sources of OxS (e.g., hyperglycemia, insulin resistance (IR), hyperlipidemia, obesity, proinflammatory cytokines) change the expression of numerous microRNAs in organs involved in the regulation of glucose and lipid metabolism and endothelium. Dysregulated microRNAs either directly or indirectly affect the expression and/or activity of molecules of antioxidative signaling pathways (SIRT1, FOXOs, Keap1/Nrf2) along with effector enzymes (e.g., GPx-1, SOD1/2, HO-1), ROS producers (e.g., NOX4/5), as well as genes of numerous signaling pathways connected with inflammation, insulin sensitivity, and lipid metabolism, thus promoting the progression of metabolic imbalance. MicroRNAs appear to be important epigenetic modifiers in managing the delicate redox balance, mediating either pro- or antioxidant biological impacts. Summarizing, microRNAs may be promising therapeutic targets in ameliorating the repercussions of OxS in MetS.

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

AIMS

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

MAIN METHODS

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

KEY FINDINGS

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

SIGNIFICANCE

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

MiR-542-5p Inhibits Hyperglycemia and Hyperlipoidemia by Targeting FOXO1 in the Liver

PURPOSE

This research was designed to investigate how miR-542-5p regulates the progression of hyperglycemia and hyperlipoidemia.

MATERIALS AND METHODS

An in vivo model with diabetic db/db mice and an in vitro model with forskolin/dexamethasone (FSK/DEX)-induced primary hepatocytes and HepG2 cells were employed in the study. Bioinformatics analysis was conducted to identify the expression of candidate miRNAs in the liver tissues of diabetic and control mice. H&E staining revealed liver morphology in diabetic and control mice. Pyruvate tolerance tests, insulin tolerance tests, and intraperitoneal glucose tolerance test were utilized to assess insulin resistance. ELISA was conducted to evaluate blood glucose and insulin levels. Red oil O staining showed lipid deposition in liver tissues. Luciferase reporter assay was used to depict binding between miR-542-5p and forkhead box O1 (FOXO1).

RESULTS

MiR-542-5p expression was under-expressed in the livers of db/db mice. Further in vitro experiments revealed that FSK/DEX, which mimics the effects of glucagon and glucocorticoids, induced cellular glucose production in HepG2 cells and in primary hepatocytes cells. Notably, these changes were reversed by miR-542-5p. We found that transcription factor FOXO1 is a target of miR-542-5p. Further in vivo study indicated that miR-542-5p overexpression decreases FOXO1 expression, thereby reversing increases in blood glucose, blood lipids, and glucose-related enzymes in diabetic db/db mice. In contrast, anti-miR-542-5p exerted an adverse influence on blood glucose and blood lipid metabolism, and its stimulatory effects were significantly inhibited by sh-FOXO1 in normal control mice.

CONCLUSION

Collectively, our results indicated that miR-542-5p inhibits hyperglycemia and hyperlipoidemia by targeting FOXO1.

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

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

Circular RNA HIPK3 contributes to hyperglycemia and insulin homeostasis by sponging miR-192-5p and upregulating transcription factor forkhead box O1

It has been shown that circular RNAs, a class of non-coding RNA molecules, play an important role in the regulation of glucose and lipid homeostasis. In the present study, we sought to investigate the function of circular RNA HIPK3 (circHIPK3) in diabetes-associated metabolic disorders, including hyperglycemia and insulin resistance. Results show that oleate stimulated circHIPK3 increase, and that circHIPK3 enhanced the stimulatory effect of oleate on adipose deposition, triglyceride (TG) content, and cellular glucose content in HepG2 cells. MiR-192-5p was the potential target of circHIPK3, since circHIPK3 significantly decreased miR-192-5p mRNA level, whereas anti-circHIPK3 significantly increased miR-192-5p mRNA level. Further study shows that transcription factor forkhead box O1 (FOXO1) was a downstream regulator of miR-192-5p, since miR-192-5p significantly decreased FOXO1 expression, whereas circHIPK3 significantly increased FOXO1 expression. Notably, the inhibitory effect of miR-192-5p was significantly reversed by circHIPK3. In vivo study shows that anti-miR-192-5p significantly increased blood glucose content, which was significantly inhibited by FOXO1 shRNA. MiR-192-5p significantly decreased adipose deposition and TG content in HepG2 cells, which was significantly reversed by the co-treatment with circHIPK3. Forskolin/dexamethasone (FSK/DEX) significantly increased cellular glucose, mRNA level of phosphoenolpyruvate carboxykinase (PEPCK) and glucose 6-phosphatase (G6Pase), and this stimulatory effect of FSK/DEX was significantly inhibited by miR-192-5p. In the presence of circHIPK3, however, the inhibitory effect of miR-192-5p was totally lost. In summary, the present study demonstrated that circHIPK3 contributes to hyperglycemia and insulin resistance by sponging miR-192-5p and up-regulating FOXO1.

Circulating miR-27a-3p as a candidate for a biomarker of whole grain diets for lipid metabolism

Circulating miR-27a-3p was involved in the process of lipid synthesis under the dietary patterns of whole grain diets, and the expression of miR-27a-3p was decreased in serum, while it was elevated both in liver and ileum.

Obesity, Insulin Resistance, and Colorectal Cancer: Could miRNA Dysregulation Play A Role?

Obesity is associated with insulin resistance and low-grade inflammation. Insulin resistance is a risk factor for cancer. A recent chapter in epigenetics is represented by microRNAs (miRNAs), which post-transcriptionally regulate gene expression. Dysregulated miRNA profiles have been associated with diseases including obesity and cancer. Herein we report dysregulated miRNAs in obesity both in animal models and in humans, and we also document dysregulated miRNAs in colorectal cancer (CRC), as example of an obesity-related cancer. Some of the described miRNAs are found to be similarly dysregulated both in obesity, insulin resistance (IR), and CRC. Thus, we present miRNAs as a potential molecular link between obesity and CRC onset and development, giving a new perspective on the role of miRNAs in obesity-associated cancers.