miR-410 enhanced hESC-derived pancreatic endoderm transplant to alleviate gestational diabetes mellitus

Insights into the development of insulin-producing cells: Precursors correlated involvement of microRNA panels

Type 1 diabetes (T1D) is a chronic autoimmune condition characterized by the destruction of pancreatic β cells, recently estimated to affect approximately 8.75 million individuals worldwide. At variance with conventional management of T1D, which relies on exogenous insulin replacement and insulinotropic drugs, emerging therapeutic strategies include transplantation of insulin-producing cells (IPCs) derived from stem cells or fully reprogrammed differentiated cells. Through the in-depth analysis of the microRNAs (miRNAs) involved in the differentiation of human embryonic stem cells (ESCs), mesenchymal stem cells (MSCs), and induced pluripotent stem cells (iPSCs), into insulin-producing cells, this review provides a comprehensive overview of the molecular mechanisms orchestrating the transformation of precursors to cells producing insulin. In addition to miR-375, involved in all differentiation processes, and to miR-7, mir-145 and miR-9, common to the generation of insulin-producing cells from at least two different sources, the literature reveals panels of miRNAs closely related to precursor cells and associated with specific events of the physiological β cell maturation. Since the forced modulation of miRNAs can direct cells development towards insulin-producing cells or modify their fate, a more comprehensive knowledge of the miRNAs involved in the cellular events leading to obtain efficient β cells could improve the diagnostic, prognostic, and therapeutic approaches to diabetes.

Extracellular Vesicles as Players in the Anti-Inflammatory Inter-Cellular Crosstalk Induced by Exercise Training

Extracellular Vesicles (EVs) are circulating particles surrounded by a plasma membrane carrying a cargo consisting of proteins, lipids, RNAs, and DNA fragments, stemming from the cells from which they originated. EV factors (i.e., miRNAs) play relevant roles in intercellular crosstalk, both locally and systemically. As EVs increasingly gained attention as potential carriers for targeted genes, the study of EV effects on the host immune response became more relevant. It has been demonstrated that EVs regulate the host immune response, executing both pro- and anti-inflammatory functions. It is also known that physical exercise triggers anti-inflammatory effects. This review underlines the role of circulating EVs as players in the anti-inflammatory events associated with the regulation of the host's immune response to physical exercise.

Identification and Validation of miR-222-3p and miR-409-3p as Plasma Biomarkers in Gestational Diabetes Mellitus Sharing Validated Target Genes Involved in Metabolic Homeostasis

Gestational diabetes mellitus (GDM) causes both maternal and fetal adverse outcomes. The deregulation of microRNAs (miRNAs) in GDM suggests their involvement in GDM pathogenesis and complications. Exosomes are extracellular vesicles (EVs) of endosomal origin, released via exocytosis into the extracellular compartment. Through EVs, miRNAs are delivered in distant target cells and are able to affect gene expression. In this study, miRNA expression was analyzed to find new miRNAs that could improve GDM classification and molecular characterization. MiRNA were profiled in total plasma and EVs in GDM patients and normal glucose tolerance (NGT) women. Samples were collected at third trimester of gestation from two diabetes centers. MiRNA expression was profiled in a discovery cohort using the multiplexed NanoString nCounter Human v3 miRNA. Validation analysis was performed in a second independent cohort using RT-qPCR. A set of miRNAs resulted to be differentially expressed (DE) in total plasma and EVs in GDM. Among them, total plasma miR-222-3p and miR-409-3p were validated in the independent cohort. MiR-222-3p levels correlated with fasting plasma glucose (FPG) (p < 0.001) and birth weight (p = 0.012), whereas miR-409-3p expression correlated with FPG (p < 0.001) and inversely with gestational age (p = 0.001). The major validated target genes of the deregulated miRNAs were consistently linked to type 2 diabetes and GDM pathophysiology. MiR-222-3p and miR-409-3p are two circulating biomarkers that could improve GDM classification power and act in the context of the molecular events leading to the metabolic alterations observed in GDM.

Non-Coding RNAs and Extracellular Vehicles: Their Role in the Pathogenesis of Gestational Diabetes Mellitus

Gestational diabetes mellitus (GDM) is defined as glucose intolerance with onset or first recognition in the second or third trimester of pregnancy. GDM has a considerable impact on health outcomes of the mother and offspring during pregnancy, delivery, and beyond. Although the exact mechanism regarding GDM remains unclear, numerous studies have suggested that non-coding RNAs, including long non-coding (lnc)RNAs, microRNAs, and circular RNAs, were involved in the pathogenesis of GDM in which they played vital regulatory roles. Additionally, several studies have revealed that extracellular vehicles also participated in the pathogenesis of GDM, highlighting their important role in this disease. Considering the lack of effective biomarkers for the early identification of and specific treatment for GDM, non-coding RNAs and extracellular vehicles may be promising biomarkers and even targets for GDM therapies. This review provides an update on our understanding of the role of non-coding RNAs and extracellular vehicles in GDM. As our understanding of the function of lncRNAs and extracellular vehicles improves, the future appears promising for their use as potential biomarkers and treatment targets for GDM in clinical practice.

Therapeutic Potentials of MicroRNAs for Curing Diabetes Through Pancreatic β-Cell Regeneration or Replacement

MicroRNAs are a type of noncoding RNAs that regulates the expression of target genes at posttranscriptional level. MicroRNAs play essential roles in regulating the expression of different genes involved in pancreatic development, β-cell mass maintenance, and β-cell function. Alteration in the level of miRNAs involved in β-cell function leads to the diabetes. Being an epidemic, diabetes threatens the life of millions of patients posing a pressing demand for its urgent resolve. However, the currently available therapies are not substantial to cure the diabetic epidemic. Thus, researchers are trying to find new ways to replenish the β-cell mass in patients with diabetes. One promising approach is the in vivo regeneration of β-cell mass or increasing the efficiency of β-cell function. Another clinical strategy is the transplantation of in vitro developed β-like cells. Owing to their role in pancreatic β-cell development, maintenance, functioning and their involvement in diabetes, overexpression or attenuation of different miRNAs can cause β-cell regeneration in vivo or can direct the differentiation of various kinds of stem/progenitor cells to β-like cells in vitro. Here, we will summarize different strategies used by researchers to investigate the therapeutic potentials of miRNAs, with focus on miR-375, for curing diabetes through β-cell regeneration or replacement.

Whole transcriptome expression profiles in placenta samples from women with gestational diabetes mellitus

AIMS/INTRODUCTION

Non-coding ribonucleic acids (ncRNAs) have recently been shown to be involved in various biological processes. However, most of these ncRNAs are of unknown function or without annotation. This study first investigated the whole transcriptome profiles of placentas to identify the potential functions that ncRNAs exerted in gestational diabetes mellitus (GDM).

MATERIALS AND METHODS

Six placenta samples from healthy pregnant women (n = 3) and GDM (n = 3) were collected to analyze the whole transcriptome profiles by high-throughput sequencing. Differentially expressed ncRNAs were further validated by quantitative real-time polymerase chain reaction on an independent set of normal (n = 20) and GDM (n = 20) placenta samples.

RESULTS

A total of 2,817 microRNAs (miRNAs), 23,339 long non-coding RNAs (lncRNAs) and 9,513 circular RNAs (circRNAs) were identified. There were 290 differentially expressed ncRNAs in GDM placentas compared with the placentas of healthy pregnant women. Two miRNAs, 86 lncRNAs and 55 circRNAs were upregulated, while two miRNAs, 86 lncRNAs and 59 circRNAs were downregulated in GDM. The expression of the selected ncRNAs, which were further validated by quantitative real-time polymerase chain reaction, was consistent with the sequencing results. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway analysis showed that the major targets of these ncRNAs were associated with insulin resistance, and abnormal glucose and lipid metabolism. A GDM-related competing endogenous RNA network suggested the interactions between lncRNAs, circRNAs, messenger RNAs and miRNAs.

CONCLUSIONS

The whole transcriptome profiles significantly differed in GDM placentas compared with the placentas of healthy pregnant women, which might be valuable for detecting novel ncRNAs, and providing new research insights into exploring the pathogenic mechanisms of GDM.

Effects of miR-152-Mediated Targeting of SOCS3 on Hepatic Insulin Resistance in Gestational Diabetes Mellitus Mice

BACKGROUND

The present study explored the effects of miR-152-mediated targeting of suppressor of cytokine signaling 3 (SOCS3) on hepatic insulin resistance (HIR) in mice with gestational diabetes mellitus (GDM). Healthy SPF C57BL/6J mice were selected to establish a GDM model.

METHODS

Mice were divided into seven groups as follows: Normal group, Model group, NC-mimic group, miR-152 mimic group, NC-pcDNA3.0 group, pcDNA3.0-SOCS group, and miR-152 mimic + pcDNA3.0-SOCS3 group. The relationship between miR-152 and SOCS3 expression was analyzed by a dual-luciferase reporter system. Islet cell morphology and expression of miR-152 and SOCS3 mRNA and protein in the islet tissue were detected by hematoxylin and eosin (HE) staining, reverse-transcription quantitative polymerase chain reaction (RT-qPCR), and western blot analysis. Fasting blood glucose (FBG) level was measured by a glucose meter while triglyceride (TG), total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), and insulin levels were determined by an automatic biochemical analyzer. Insulin resistance index (HOMA-IR) was calculated by the formula FBG × FINS/22.5.

RESULTS

The results showed that the levels of miR-152, SOCS3, FBG, fasting insulin (FINS), TG, and TC increased, and HDL-C content decreased in other groups as compared with those in the Normal group (all p < 0.05). Oral glucose tolerance test (OGTT), FBG, FINS, TG, TC, and HDL-C values showed an opposite trend in miR-152 mimic and pcDNA3.0-SOCS3 groups as compared with the Model group (all p < 0.05).

CONCLUSIONS

miR-152 can inhibit HIR in GDM mice by downregulating the expression of SOCS3.

Non-Coding RNA: Role in Gestational Diabetes Pathophysiology and Complications

Gestational Diabetes Mellitus (GDM) is defined as glucose intolerance that develops in the second or third trimester of pregnancy. GDM can lead to short-term and long-term complications both in the mother and in the offspring. Diagnosing and treating this condition is therefore of great importance to avoid poor pregnancy outcomes. There is increasing interest in finding new markers with potential diagnostic, prognostic and therapeutic utility in GDM. Non-coding RNAs (ncRNAs), including microRNAs, long non-coding RNAs and circular RNAs, are critically involved in metabolic processes and their dysregulated expression has been reported in several pathological contexts. The aberrant expression of several circulating or placenta-related ncRNAs has been linked to insulin resistance and β-cell dysfunction, the key pathophysiological features of GDM. Furthermore, significant associations between altered ncRNA profiles and GDM-related complications, such as macrosomia or trophoblast dysfunction, have been observed. Remarkably, the deregulation of ncRNAs, which might be linked to a detrimental intrauterine environment, can lead to changes in the expression of target genes in the offspring, possibly contributing to the development of long-term GDM-related complications, such as metabolic and cardiovascular diseases. In this review, all the recent findings on ncRNAs and GDM are summarized, particularly focusing on the molecular aspects and the pathophysiological implications of this complex relationship.

Human stem cell models: lessons for pancreatic development and disease

A comprehensive understanding of mechanisms that underlie the development and function of human cells requires human cell models. For the pancreatic lineage, protocols have been developed to differentiate human pluripotent stem cells (hPSCs) into pancreatic endocrine and exocrine cells through intermediates resembling in vivo development. In recent years, this differentiation system has been employed to decipher mechanisms of pancreatic development, congenital defects of the pancreas, as well as genetic forms of diabetes and exocrine diseases. In this review, we summarize recent insights gained from studies of pancreatic hPSC models. We discuss how genome-scale analyses of the differentiation system have helped elucidate roles of chromatin state, transcription factors, and noncoding RNAs in pancreatic development and how the analysis of cells with disease-relevant mutations has provided insight into the molecular underpinnings of genetically determined diseases of the pancreas.

Micromanaging aerobic respiration and glycolysis in cancer cells

BACKGROUND

Cancer cells possess a common metabolic phenotype, rewiring their metabolic pathways from mitochondrial oxidative phosphorylation to aerobic glycolysis and anabolic circuits, to support the energetic and biosynthetic requirements of continuous proliferation and migration. While, over the past decade, molecular and cellular studies have clearly highlighted the association of oncogenes and tumor suppressors with cancer-associated glycolysis, more recent attention has focused on the role of microRNAs (miRNAs) in mediating this metabolic shift. Accumulating studies have connected aberrant expression of miRNAs with direct and indirect regulation of aerobic glycolysis and associated pathways.

SCOPE OF REVIEW

This review discusses the underlying mechanisms of metabolic reprogramming in cancer cells and provides arguments that the earlier paradigm of cancer glycolysis needs to be updated to a broader concept, which involves interconnecting biological pathways that include miRNA-mediated regulation of metabolism. For these reasons and in light of recent knowledge, we illustrate the relationships between metabolic pathways in cancer cells. We further summarize our current understanding of the interplay between miRNAs and these metabolic pathways. This review aims to highlight important metabolism-associated molecular components in the hunt for selective preventive and therapeutic treatments.

MAJOR CONCLUSIONS

Metabolism in cancer cells is influenced by driver mutations but is also regulated by posttranscriptional gene silencing. Understanding the nuanced regulation of gene expression in these cells and distinguishing rapid cellular responses from chronic adaptive mechanisms provides a basis for rational drug design and novel therapeutic strategies.

Effects of Acute Aerobic Exercise on Rats Serum Extracellular Vesicles Diameter, Concentration and Small RNAs Content

Physical exercise stimulates organs, mainly the skeletal muscle, to release a broad range of molecules, recently dubbed exerkines. Among them, RNAs, such as miRNAs, piRNAs, and tRNAs loaded in extracellular vesicles (EVs) have the potential to play a significant role in the way muscle and other organs communicate to translate exercise into health. Low, moderate and high intensity treadmill protocols were applied to rat groups, aiming to investigate the impact of exercise on serum EVs and their associated small RNA molecules. Transmission electron microscopy, resistive pulse sensing, and western blotting were used to investigate EVs morphology, size distribution, concentration and EVs marker proteins. Small RNA libraries from EVs RNA were sequenced. Exercise did not change EVs size, while increased EVs concentration. Twelve miRNAs were found differentially expressed after exercise: rno-miR-128-3p, 103-3p, 330-5p, 148a-3p, 191a-5p, 10b-5p, 93-5p, 25-3p, 142-5p, 3068-3p, 142-3p, and 410-3p. No piRNA was found differentially expressed, and one tRNA, trna8336, was found down-regulated after exercise. The differentially expressed miRNAs were predicted to target genes involved in the MAPK pathway. A single bout of exercise impacts EVs and their small RNA load, reinforcing the need for a more detailed investigation into EVs and their load as mediators of health-promoting exercise.

MiR-34b-3 and miR-449a inhibit malignant progression of nasopharyngeal carcinoma by targeting lactate dehydrogenase A

MicroRNA expression profiling assays have shown that miR-34b/c and miR-449a are down-regulated in nasopharyngeal carcinoma (NPC); however, the targets and functions of miR-34b/c and miR-449a in the pathologenesis of NPC remain elusive. In this study, we verified miR-34b/c and miR-449a were significantly reduced with the advance of NPC. Overexpression of miR-34b-3 and miR-449a suppressed the growth of NPC cells in culture and mouse tumor xenografts. Using tandem mass tags for quantitative labeling and LC-MS/MS analysis to investigate protein changes after restoring expression of miR-34b-3, 251 proteins were found to be down-regulated after miR-34b-3 transfection. Through 3 replicate experiments, we found that miR-34b-3 regulated the expression of 15 potential targeted genes mainly clustered in the key enzymes of glycolysis metabolism, including lactate dehydrogenase A (LDHA). Further investigation revealed that miR-34b-3 and miR-449a negatively regulated LDHA by binding to the 3′ untranslated regions of LDHA. Furthermore, LDHA overexpression rescued the miR-34b-3 and miR-449a induced tumor inhibition effect in CNE2 cells. In addition, miR-34b-3 and miR-449a suppressed LDH activity and reduced LD content, which were directly induced by downregulation of the LDHA. Our findings suggest that miR-34b-3 and miR-449a suppress the development of NPC through regulation of glycolysis via targeting LDHA and may be potential therapeutic targets for the treatment of NPC.

MicroRNAs as stress regulators in pancreatic beta cells and diabetes

Background

MicroRNAs have emerged as important regulatory non-coding RNAs that tune cellular responses to physiological perturbations and disease conditions. An increasing body of literature underlines the important roles of miRNA function in pancreatic β-cells in response to metabolic, genetic and inflammatory stress. Lessons from genetic loss- and gain-of-function studies have implicated several highly expressed and evolutionary conserved miRNAs in stress signal modulation, resolution and buffering, thereby forming stabilizing miRNA networks that preserve β-cell differentiation, function, proliferation and cell survival.

Scope of Review

This review will summarize our current knowledge of how biologically relevant miRNAs regulate stress responses in pancreatic β-cells, discuss the challenges and opportunities associated with using secreted miRNAs as biomarkers and forecast how mechanistic knowledge of miRNA function can be exploited in developing miRNA-based therapeutics.

Major Conclusions

miRNAs play important roles in the function, differentiation, proliferation, and survival of pancreatic β-cells. Many miRNA families that are regulated by metabolic, genetic, and inflammatory stressors have been found to coordinate the adaptive responses of β-cells in vivo in conditions such as obesity and diabetes.

MicroRNAs and altered metabolism of clear cell renal cell carcinoma: Potential role as aerobic glycolysis biomarkers

BACKGROUND

Warburg Effect is a metabolic switch that occurs in most of cancer cells but its advantages are not fully understood. This switch is known to happen in renal cell carcinoma (RCC), which is the most common solid cancer of the adult kidney. RCC carcinogenesis is related to pVHL loss and Hypoxia Inducible Factor (HIF) activation, ultimately leading to the activation of several genes related to glycolysis. MicroRNAs (miRNAs) regulate gene expression at a post-transcriptional level and are also deregulated in several cancers, including RCC.

SCOPE OF REVIEW

This review focuses in the miRNAs that direct target enzymes involved in glycolysis and that are deregulated in several cancers. It also reviews the possible application of miRNAs in the improvement of clinical patients' management.

MAJOR CONCLUSIONS

Several miRNAs that direct target enzymes involved in glycolysis are downregulated in cancer, strongly influencing the Warburg Effect. Due to this strong influence, FDG-PET can possibly benefit from measurement of these miRNAs. Restoring their levels can also bring an improvement to the current therapies.

GENERAL SIGNIFICANCE

Despite being known for almost a hundred years, the Warburg Effect is not fully understood. MiRNAs are now known to be intrinsically connected with this effect and present an opportunity to understand it. They also open a new door to improve current diagnosis and prognosis tests as well as to complement current therapies. This is urgent for cancers like RCC, mostly due to the lack of an efficient screening test for early relapse detection and follow-up and the development of resistance to current therapies.

miR-30a-5p suppresses breast tumor growth and metastasis through inhibition of LDHA-mediated Warburg effect

Lactate dehydrogenase A (LDHA), a key enzyme regulating aerobic glycolysis, is overexpressed in many human cancers, and correlates with poor clinical outcomes. Aerobic glycolysis is a hallmark of cancer, and drugs targeting its regulators, including LDHA, are being developed. However, the mechanisms of LDHA inhibition and the physiological significance of the LDHA inhibitors in cancer cells are unclear. Here, we show that microRNA-30a-5p (miR-30a-5p) suppresses LDHA expression by directly targeting its 3'-UTR. Through inhibition of LDHA, miR-30a-5p dampens glycolysis by decreasing glucose uptake, lactate production, ATP generation, and extracellular acidification rate (ECAR), and increasing oxygen consumption rate (OCR) in breast cancer cells. Importantly, glycolysis regulated by miR-30a-5p is critical for its regulating breast tumor growth and metastasis both in vitro and in vivo. In breast cancer patients, miR-30a-5p expression is negatively correlated with LDHA expression. Moreover, patients who had increased glucose uptake in tumors assessed by PET scans showed decreased miR-30a-5p expression and increased expression of LDHA. Our findings provide clues regarding the role of miR-30a-5p as a tumor suppressor in breast cancer through the inhibition of LDHA. Targeting LDHA through miR-30a-5p could be a potential therapeutic strategy in breast cancer.

MiRNAs in β-Cell Development, Identity, and Disease

Pancreatic β-cells regulate glucose metabolism by secreting insulin, which in turn stimulates the utilization or storage of the sugar by peripheral tissues. Insulin insufficiency and a prolonged period of insulin resistance are usually the core components of type 2 diabetes (T2D). Although, decreased insulin levels in T2D have long been attributed to a decrease in β-cell function and/or mass, this model has recently been refined with the recognition that a loss of β-cell “identity” and dedifferentiation also contribute to the decline in insulin production. MicroRNAs (miRNAs) are key regulatory molecules that display tissue-specific expression patterns and maintain the differentiated state of somatic cells. During the past few years, great strides have been made in understanding how miRNA circuits impact β-cell identity. Here, we review current knowledge on the role of miRNAs in regulating the acquisition of the β-cell fate during development and in maintaining mature β-cell identity and function during stress situations such as obesity, pregnancy, aging, or diabetes. We also discuss how miRNA function could be harnessed to improve our ability to generate β-cells for replacement therapy for T2D.