Decreased miR-146 expression in peripheral blood mononuclear cells is correlated with ongoing islet autoimmunity in type 1 diabetes patients 1miR-146

Evaluation of miRNA-146a, miRNA-34a, and pro-inflammatory cytokines as a potential early indicators for type 1 diabetes mellitus

Background

Type I diabetes mellitus (T1DM) is one of the most common chronic autoimmune diseases worldwide. miRNAs are a class of small non-coding RNA molecules that have been linked to immune system functions, β-cell metabolism, proliferation, and death, all of which contribute to pathogenesis of TIDM. Dysregulated miRNAs have been identified in Egyptian TIDM patients.

Aim

Several miRNAs were profiled in Egyptian TIDM patients to determine whether they can be used as molecular biomarkers for T1DM. The relationship between the investigated miRNAs and pro-inflammatory cytokines (TNF-α and IL-6) has also been evaluated in the development of TIDM, in addition to the creation of a proposed model for TIDM prediction.

Patients & methods

Case-control study included 177 Egyptian patients with confirmed type I diabetes mellitus and 177 healthy individuals. MiRNA-34 and miRNA-146 were detected in serum samples using real-time PCR, whereas TNF-α and IL-6 levels were assessed using ELIZA.

Results

Patients with TIDM showed a significant decrease in the expression of miRNA-146, with a cut-off value ≤ 3.3, 48 % specificity, and 92.1 % sensitivity, whereas miRNA-34 had the highest sensitivity (95.5 %) and specificity (97.2 %) for differentiating diabetic patients from controls. Furthermore, other diagnostic proinflammatory markers showed lower sensitivity and specificity.

Conclusion

Serum levels of miRNA-34a, miRNA-146, IL-6, and TNF-α provide new insights into T1DM pathogenesis and could be used for screening and diagnosis purposes. They can be also a potential therapeutic target, as well as allowing for more strategies to improve T1DM disease outcomes.

Circulating non-coding RNA in type 1 diabetes mellitus as a source of potential biomarkers - An emerging role of sex difference

Non-coding RNAs (ncRNAs), such as microRNA, long non-coding RNA, and circular RNA, are considered essential regulatory molecules mediating many cellular processes. Moreover, an increasing number of studies have investigated the role of ncRNAs in cancers and various metabolic disorders, including diabetes mellitus. Interestingly, some circulating ncRNA detected in body fluids may serve as novel biomarkers. There is still a lack of conventional biomarkers that detect the early stage of type 1 diabetes mellitus. Many circulating microRNA, long non-coding RNA, and circular RNA show aberrant expression in type 1 diabetes patients compared to healthy individuals. However, most studies have focused on circulating microRNA rather than long non-coding RNA or circular RNA. In addition, a few studies have evaluated sex differences in ncRNA biomarkers. Therefore, this article summarises current knowledge about circulating ncRNAs as potential biomarkers for type 1 diabetes and explores the effects of sex on such biomarkers.

Dysregulation of miR-146a is associated with exacerbated inflammation, oxidative and endoplasmic reticulum stress in the progression of diabetic foot ulcer

Recent evidence has implicated the role of microRNA-146a (miR-146a) in regulating inflammatory responses. In the present study, we investigated the role of miRNA-146a in the progression of diabetic foot ulcer (DFU) in type 2 diabetes mellitus patients (T2DM) and studied its correlation with stress mediators such as Endoplasmic Reticulum (ER) and oxidative stress. Ninety subjects were enrolled and evenly distributed among three groups: Controls (n = 30), T2DM without complications (n = 30) and T2DM with foot ulcers (n = 30). Subsequently, each group was further subdivided based on the University of Texas classification. Peripheral blood was collected from all the study subjects, while tissue biopsies were taken only from DFU patients. Total RNA from both PBMCs and wound tissues were isolated using miRNA isolation kit and qPCR was performed to check the expression of miR-146a, ER stress and oxidative stress markers. Our findings revealed a significant decrease in miR-146a expression among T2DM patients with Grade 2 and Grade 3 DFUs compared with those with Grade 0 and Grade 1 DFUs. Notably, inflammatory genes regulated by miR-146a, including TRAF6, IRAK-1 and ADAM, were all upregulated in T2DM patients with Grade 2 and Grade 3 DFUs. Moreover, reduced miR-146a levels were correlated with increased markers of ER stress and oxidative stress in Grade 2 and Grade 3 DFU patients. Furthermore, our in vitro experiment using mouse 3T3 fibroblasts demonstrated a downregulation of miR-146a following induction of hyperglycaemia, ER stress and oxidative stress in these cells. These findings suggest a potential link between diminished miR-146a expression and heightened oxidative and ER stress in T2DM patients with more severe grades of DFUs. Our results imply that targeting miR-146a may hold therapeutic promise for managing disease progression in DFU patients, as it could help alleviate oxidative and ER stress associated with diabetic complications.

A set of circulating microRNAs belonging to the 14q32 chromosome locus identifies two subgroups of individuals with recent-onset type 1 diabetes

Circulating microRNAs (miRNAs) are linked to the onset and progression of type 1 diabetes mellitus (T1DM), thus representing potential disease biomarkers. In this study, we employed a multiplatform sequencing approach to analyze circulating miRNAs in an extended cohort of prospectively evaluated recent-onset T1DM individuals from the INNODIA consortium. Our findings reveal that a set of miRNAs located within T1DM susceptibility chromosomal locus 14q32 distinguishes two subgroups of individuals. To validate our results, we conducted additional analyses on a second cohort of T1DM individuals, confirming the identification of these subgroups, which we have named cluster A and cluster B. Remarkably, cluster B T1DM individuals, who exhibit increased expression of a set of 14q32 miRNAs, show better glycemic control and display a different blood immunomics profile. Our findings suggest that this set of circulating miRNAs can identify two different T1DM subgroups with distinct blood immunomics at baseline and clinical outcomes during follow-up.

Circulating levels of miR125a, miR126, and miR146a-5p in patients with obstructive sleep apnea and their relation with markers of endothelial dysfunction

BACKGROUND

obstructive sleep apnea (OSA) is a prevalent sleep disorder that is associated with increased risk factors for cardiovascular diseases (CVDs). Oxidative stress, insulin resistance, inflammation, and endothelial dysfunction are increased in OSA patients and microRNAs (miRs) are regulatory elements that influence these pathological mechanisms. miR125a, miR126, and miR146a-5p play a role in these pathological mechanisms and have not been evaluated in patients with OSA.

METHOD

This case-control study was performed on 90 OSA patients and 34 controls. Circulating levels of miR125a, miR126, and miR146a-5 were determined using real-time PCR, and serum levels of hsCRP, ICAM-1, and VCAM-1 were evaluated using ELISA kits.

RESULTS

miR125a and miR146a were elevated in patients with OSA compared to controls while miR126 decreased significantly. All three miRs indicated a remarkable difference between the mild-OSA group compared to the severe-OSA group. Furthermore, patients with OSA showed elevated levels of hsCRP, ICAM-1, and VCAM-1. Multiple linear regression indicated an independent association of miR125a with ICAM-1 and hsCRP, miR126 associated with VCAM-1 and total cholesterol, and miR146a-5p represented an association with apnea-hypopnea index and ICAM-1. Furthermore, miR146a-5p illustrated a good diagnostic ability to differentiate between OSA and controls.

CONCLUSIONS

Circulating miR125a, miR126, and miR146a-5p fluctuations in patients with OSA and their relations with markers of endothelial dysfunction provide in vivo evidence and suggest a potential role for these miRs with endothelial dysfunction in patients with OSA.

Genetics of diabetes

Diabetes mellitus is a complicated disease characterized by a complex interplay of genetic, epigenetic, and environmental variables. It is one of the world's fastest-growing diseases, with 783 million adults expected to be affected by 2045. Devastating macrovascular consequences (cerebrovascular disease, cardiovascular disease, and peripheral vascular disease) and microvascular complications (like retinopathy, nephropathy, and neuropathy) increase mortality, blindness, kidney failure, and overall quality of life in individuals with diabetes. Clinical risk factors and glycemic management alone cannot predict the development of vascular problems; multiple genetic investigations have revealed a clear hereditary component to both diabetes and its related complications. In the twenty-first century, technological advancements (genome-wide association studies, next-generation sequencing, and exome-sequencing) have led to the identification of genetic variants associated with diabetes, however, these variants can only explain a small proportion of the total heritability of the condition. In this review, we address some of the likely explanations for this "missing heritability", for diabetes such as the significance of uncommon variants, gene-environment interactions, and epigenetics. Current discoveries clinical value, management of diabetes, and future research directions are also discussed.

A Data-Mining Approach to Identify NF-kB-Responsive microRNAs in Tissues Involved in Inflammatory Processes: Potential Relevance in Age-Related Diseases

The nuclear factor NF-kB is the master transcription factor in the inflammatory process by modulating the expression of pro-inflammatory genes. However, an additional level of complexity is the ability to promote the transcriptional activation of post-transcriptional modulators of gene expression as non-coding RNA (i.e., miRNAs). While NF-kB’s role in inflammation-associated gene expression has been extensively investigated, the interplay between NF-kB and genes coding for miRNAs still deserves investigation. To identify miRNAs with potential NF-kB binding sites in their transcription start site, we predicted miRNA promoters by an in silico analysis using the PROmiRNA software, which allowed us to score the genomic region’s propensity to be miRNA cis-regulatory elements. A list of 722 human miRNAs was generated, of which 399 were expressed in at least one tissue involved in the inflammatory processes. The selection of “high-confidence” hairpins in miRbase identified 68 mature miRNAs, most of them previously identified as inflammamiRs. The identification of targeted pathways/diseases highlighted their involvement in the most common age-related diseases. Overall, our results reinforce the hypothesis that persistent activation of NF-kB could unbalance the transcription of specific inflammamiRNAs. The identification of such miRNAs could be of diagnostic/prognostic/therapeutic relevance for the most common inflammatory-related and age-related diseases.

Identification of key regulatory genes and their working mechanisms in type 1 diabetes

BACKGROUND

Type 1 diabetes (T1D) is an autoimmune disease characterized by the destruction of beta cells in pancreatic islets. Identification of the key genes involved in T1D progression and their mechanisms of action may contribute to a better understanding of T1D.

METHODS

The microarray profile of T1D-related gene expression was searched using the Gene Expression Omnibus (GEO) database. Then, the expression data of two messenger RNAs (mRNAs) were integrated for Weighted Gene Co-Expression Network Analysis (WGCNA) to generate candidate genes related to T1D. In parallel, T1D microRNA (miRNA) data were analyzed to screen for possible regulatory miRNAs and their target genes. An miRNA-mRNA regulatory network was then established to predict the key regulatory genes and their mechanisms.

RESULTS

A total of 24 modules (i.e., clusters/communities) were selected using WGCNA analysis, in which three modules were significantly associated with T1D. Further correlation analysis of the gene module revealed 926 differentially expressed genes (DEGs), of which 327 genes were correlated with T1D. Analysis of the miRNA microarray showed that 13 miRNAs had significant expression differences in T1D. An miRNA-mRNA network was established based on the prediction of miRNA target genes and the combined analysis of mRNA, in which the target genes of two miRNAs were found in T1D correlated genes.

CONCLUSION

An miRNA-mRNA network for T1D was established, based on which 2 miRNAs and 12 mRNAs were screened, suggesting that they may play key regulatory roles in the initiation and development of T1D.

miRNA-encapsulated abiotic materials and biovectors for cutaneous and oral wound healing: Biogenesis, mechanisms, and delivery nanocarriers

MicroRNAs (miRNAs) as therapeutic agents have attracted increasing interest in the past decade owing to their significant effectiveness in treating a wide array of ailments. These polymerases II-derived noncoding RNAs act through post-transcriptional controlling of different proteins and their allied pathways. Like other areas of medicine, researchers have utilized miRNAs for managing acute and chronic wounds. The increase in the number of patients suffering from either under-healing or over-healing wound demonstrates the limited efficacy of the current wound healing strategies and dictates the demands for simpler approaches with greater efficacy. Various miRNA can be designed to induce pathway beneficial for wound healing. However, the proper design of miRNA and its delivery system for wound healing applications are still challenging due to their limited stability and intracellular delivery. Therefore, new miRNAs are required to be identified and their delivery strategy needs to be optimized. In this review, we discuss the diverse roles of miRNAs in various stages of wound healing and provide an insight on the most recent findings in the nanotechnology and biomaterials field, which might offer opportunities for the development of new strategies for this chronic condition. We also highlight the advances in biomaterials and delivery systems, emphasizing their challenges and resolutions for miRNA-based wound healing. We further review various biovectors (e.g., adenovirus and lentivirus) and abiotic materials such as organic and inorganic nanomaterials, along with dendrimers and scaffolds, as the delivery systems for miRNA-based wound healing. Finally, challenges and opportunities for translation of miRNA-based strategies into clinical applications are discussed.

Exploration of cross-talk and pyroptosis-related gene signatures and molecular mechanisms between periodontitis and diabetes mellitus via peripheral blood mononuclear cell microarray data analysis

OBJECTIVES

This bioinformatics study is aimed at identifying cross-talk genes, pyroptosis-related genes, and related pathways between periodontitis (PD) and diabetes mellitus (DM), which includes type 1 diabetes (T1DM) and type 2 diabetes (T2DM).

METHODS

GEO datasets containing peripheral blood mononuclear cell (PBMC) data of PD and DM were acquired. After batch correction and normalization, differential expression analysis was performed to identify the differentially expressed genes (DEGs). And cross-talk genes in the PD-T1DM pair and the PD-T2DM pair were identified by overlapping DEGs with the same trend in each pair. The weighted gene coexpression network analysis (WGCNA) algorithm helped locate the pyroptosis-related genes that are related to cross-talk genes. Receiver-operating characteristic (ROC) curve analysis confirmed the predictive accuracy of these hub genes in diagnosing PD and DM. The correlation between hub genes and the immune microenvironment of PBMC in these diseases was investigated by Spearman correlation analysis. The experimentally validated protein-protein interaction (PPI) and gene-pathway network were constructed. Subnetwork analysis helped identify the key pathway connecting DM and PD.

RESULTS

Hub genes in the PD-T1DM pair (HBD, NLRC4, AIM2, NLRP2) and in the PD-T2DM pair (HBD, IL-1Β, AIM2, NLRP2) were identified. The similarity and difference in the immunocytes infiltration levels and immune pathway scores of PD and DM were observed. ROC analysis showed that AIM2 and HBD exhibited pleasant discrimination ability in all diseases, and the subnetwork of these genes indicated that the NOD-like receptor signaling pathway is the most potentially relevant pathway linking PD and DM.

CONCLUSION

HBD and AIM2 could be the most relevant potential cross-talk and pyroptosis-related genes, and the NOD-like receptor signaling pathway could be the top candidate molecular mechanism linking PD and DM, supporting a potential pathophysiological relationship between PD and DM.

Highlighting the Role of Obesity and Insulin Resistance in Type 1 Diabetes and Its Associated Cardiometabolic Complications

PURPOSE OF REVIEW

This narrative review appraises research data on the potentially harmful effect of obesity and insulin resistance (IR) co-existence with type 1 diabetes mellitus (T1DM)-related cardiovascular (CVD) complications and evaluates possible therapeutic options.

RECENT FINDINGS

Obesity and IR have increasingly been emerging in patients with T1DM. Genetic, epigenetic factors, and subcutaneous insulin administration are implicated in the pathogenesis of this coexistence. Accumulating evidence implies that the concomitant presence of obesity and IR is an independent predictor of worse CVD outcomes. The prevalence of obesity and IR has increased in patients with T1DM. This increase can be partly attributed to general population trends but, additionally, to iatrogenic weight gain caused by insulin treatment. This association might be the missing link explaining the excess CVD burden observed in patients with T1DM despite optimal glycemic control. Data on newer agents for type 2 diabetes mellitus (T2DM) treatment are unraveling novel ways to challenge this aggravating coexistence.

A genome-wide functional genomics approach uncovers genetic determinants of immune phenotypes in type 1 diabetes

Background:

The large inter-individual variability in immune-cell composition and function determines immune responses in general and susceptibility o immune-mediated diseases in particular. While much has been learned about the genetic variants relevant for type 1 diabetes (T1D), the pathophysiological mechanisms through which these variations exert their effects remain unknown.

Methods:

Blood samples were collected from 243 patients with T1D of Dutch descent. We applied genetic association analysis on >200 immune-cell traits and >100 cytokine production profiles in response to stimuli measured to identify genetic determinants of immune function, and compared the results obtained in T1D to healthy controls.

Results:

Genetic variants that determine susceptibility to T1D significantly affect T cell composition. Specifically, the CCR5+ regulatory T cells associate with T1D through the CCR region, suggesting a shared genetic regulation. Genome-wide quantitative trait loci (QTLs) mapping analysis of immune traits revealed 15 genetic loci that influence immune responses in T1D, including 12 that have never been reported in healthy population studies, implying a disease-specific genetic regulation.

Conclusions:

This study provides new insights into the genetic factors that affect immunological responses in T1D.

Funding:

This work was supported by an ERC starting grant (no. 948207) and a Radboud University Medical Centre Hypatia grant (2018) to YL and an ERC advanced grant (no. 833247) and a Spinoza grant of the Netherlands Association for Scientific Research to MGN CT received funding from the Perspectief Biomarker Development Center Research Programme, which is (partly) financed by the Netherlands Organisation for Scientific Research (NWO). AJ was funded by a grant from the European Foundation for the Study of Diabetes (EFSD/AZ Macrovascular Programme 2015). XC was supported by the China Scholarship Council (201706040081).

Every year around the world, over 100,000 people are diagnosed with type 1 diabetes. This disease develops when the immune system mistakenly destroys the cells that produce a hormone called insulin, leaving affected individuals unable to regulate their blood sugar levels. Type 1 diabetes patients must rely on regular injections of manufactured insulin to survive.

The composition and activity of the human immune system is under genetic control, and people with certain changes in their genes are more susceptible than others to develop type 1 diabetes. Previous studies have identified around 60 locations in the human DNA (known as loci) associated with the condition, but it remains unclear how these loci influence the immune system and whether diabetes will emerge.

Chu, Janssen, Koenen et al. explored how variations in genetic information can influence the composition of the immune system, and the type of molecules it releases to perform its role. To do so, blood samples from 243 individuals of Dutch descent with type 1 diabetes were collected, and genetic associations were investigated.

The results revealed that a major type of immune actors known as T cells are under the control of genetic factors associated with type 1 diabetes susceptibility. For instance, a specific type of T cells showed shared genetic control with type 1 diabetes. In addition, 15 loci were identified that influenced immune responses in the patients. Among those, 12 have never been reported to be involved in immune responses in healthy people, implying that these regions might only regulate the immune system of individuals with type 1 diabetes and other similar disorders. Finally, Chu, Janssen, Koenen et al. propose 11 genes within the identified loci as potential targets for new diabetes medication. These results represent an important resource for researchers exploring the genetic and immune basis of type 1 diabetes, and they could open new avenues for drug development.

Identification of miRNA-mRNA-TF regulatory networks in peripheral blood mononuclear cells of type 1 diabetes

BACKGROUND

Type 1 diabetes (T1D) is a T lymphocyte-mediated and B lymphocyte-assisted autoimmune disease. We aimed to identify abnormally expressed genes in peripheral blood mononuclear cells (PBMCs) of T1D and explore their possible molecular regulatory network.

METHODS

Expression datasets were downloaded from the Gene Expression Omnibus (GEO) database. Then, the differentially expressed genes (DEGs) and differentially expressed miRNAs (DEmiRNAs) were identified, and functional enrichment and immune cell infiltration analysis were performed. The starBase, miRTarBase, TarBase, JASPAR, ENCODE, and TRRUST databases constructed the miRNA-mRNA-TF regulatory network. The ROC curves were plotted to evaluate the sensitivity and specificity of miRNAs and mRNAs.

RESULT

A total of 216 DEGs directly or indirectly related to type I diabetes mellitus, natural killer cell-mediated cytotoxicity, Th1, and Th2 cell differentiation, and the IL-17 and TNF signaling pathways were obtained. The miRNA-mRNA-TF network indicates that miR-320a and SOX5 are the only miRNAs and TFs that both target ADM and RRAGD. The ROC curves showed that ADM (0.9375), RRAGD (0.8958), and hsa-mir-320a (0.9417) had high accuracy in T1D diagnosis.

CONCLUSION

The constructed regulatory networks, including miR-320a/ADM/SOX5 and miR-320a/RRAGD/SOX5, may provide new insight into the mechanisms of development and progression in T1D.

Identification of Key Genes and Pathways in Peripheral Blood Mononuclear Cells of Type 1 Diabetes Mellitus by Integrated Bioinformatics Analysis

BACKGROUND

The onset and progression of type 1 diabetes mellitus (T1DM) is closely related to autoimmunity. Effective monitoring of the immune system and developing targeted therapies are frontier fields in T1DM treatment. Currently, the most available tissue that reflects the immune system is peripheral blood mononuclear cells (PBMCs). Thus, the aim of this study was to identify key PBMC biomarkers of T1DM.

METHODS

Common differentially expressed genes (DEGs) were screened from the Gene Expression Omnibus (GEO) datasets GSE9006, GSE72377, and GSE55098, and PBMC mRNA expression in T1DM patients was compared with that in healthy participants by GEO2R. Gene Ontology, Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway and protein-protein interaction (PPI) network analyses of DEGs were performed using the Cytoscape, DAVID, and STRING databases. The vital hub genes were validated by reverse transcription-polymerase chain reaction using clinical samples. The disease-gene-drug interaction network was built using the Comparative Toxicogenomics Database (CTD) and Drug Gene Interaction Database (DGIdb).

RESULTS

We found that various biological functions or pathways related to the immune system and glucose metabolism changed in PBMCs from T1DM patients. In the PPI network, the DEGs of module 1 were significantly enriched in processes including inflammatory and immune responses and in pathways of proteoglycans in cancer. Moreover, we focused on four vital hub genes, namely, chitinase-3-like protein 1 (CHI3L1), C-X-C motif chemokine ligand 1 (CXCL1), matrix metallopeptidase 9 (MMP9), and granzyme B (GZMB), and confirmed them in clinical PBMC samples. Furthermore, the disease-gene-drug interaction network revealed the potential of key genes as reference markers in T1DM.

CONCLUSION

These results provide new insight into T1DM pathogenesis and novel biomarkers that could be widely representative reference indicators or potential therapeutic targets for clinical applications.

MicroRNAs and Diabetes Mellitus Type 1

Type 1 diabetes mellitus is a multifactorial, progressive, autoimmune disease with a strong genetic feature that can affect multiple organs, including the kidney, eyes, and nerves. Early detection of type 1 diabetes can help critically to avoid serious damages to these organs. MicroRNAs are small RNA molecules that act in post-transcriptional gene regulation by attaching to the complementary sequence in the 3'-untranslated region of their target genes. Alterations in the expression of microRNA coding genes are extensively reported in several diseases, such as type 1 diabetes. Presenting non-invasive biomarkers for early detection of type 1 diabetes by quantifying microRNAs gene expression level can be a significant step in biotechnology and medicine. This review discusses the area of microRNAs dysregulation in type 1 diabetes and affected molecular mechanisms involved in pancreatic islet cell formation and dysregulation in the expression of inflammatory elements as well as pro-inflammatory cytokines.

Non-coding RNAs in diabetes mellitus and diabetic cardiovascular disease

More than 10% of the world's population already suffers from varying degrees of diabetes mellitus (DM), but there is still no cure for the disease. Cardiovascular disease (CVD) is one of the most common and dangerous of the many health complications that can be brought on by DM, and has become the leading cause of death in people with diabetes. While research on DM and associated CVD is advancing, the specific mechanisms of their development are still unclear. Given the threat of DM and CVD to humans, the search for new predictive markers and therapeutic ideas is imminent. Non-coding RNAs (ncRNAs) have been a popular subject of research in recent years. Although they do not encode proteins, they play an important role in living organisms, and they can cause disease when their expression is abnormal. Numerous studies have observed aberrant ncRNAs in patients with DM complications, suggesting that they may play an important role in the development of DM and CVD and could potentially act as biomarkers for diagnosis. There is additional evidence that treatment with existing drugs for DM, such as metformin, alters ncRNA expression levels, suggesting that regulation of ncRNA expression may be a key mechanism in future DM treatment. In this review, we assess the role of ncRNAs in the development of DM and CVD, as well as the evidence for ncRNAs as potential therapeutic targets, and make use of bioinformatics to analyze differential ncRNAs with potential functions in DM.

ZMYND8 mediated liquid condensates spatiotemporally decommission the latent super-enhancers during macrophage polarization

Super-enhancers (SEs) govern macrophage polarization and function. However, the mechanism underlying the signal-dependent latent SEs remodeling in macrophages remains largely undefined. Here we show that the epigenetic reader ZMYND8 forms liquid compartments with NF-κB/p65 to silence latent SEs and restrict macrophage-mediated inflammation. Mechanistically, the fusion of ZMYND8 and p65 liquid condensates is reinforced by signal-induced acetylation of p65. Then acetylated p65 guides the ZMYND8 redistribution onto latent SEs de novo generated in polarized macrophages, and consequently, recruit LSD1 to decommission latent SEs. The liquidity characteristic of ZMYND8 is critical for its regulatory effect since mutations coagulating ZMYND8 into solid compartments disable the translocation of ZMYND8 and its suppressive function. Thereby, ZMYND8 serves as a molecular rheostat to switch off latent SEs and control the magnitude of the immune response. Meanwhile, we propose a phase separation model by which the latent SEs are fine-tuned in a spatiotemporal manner.

Macrophages employ epigenetic remodeling, especially the regulation of superenhancers (SEs), to promote classical polarization and function; whether liquid-liquid phase separation (LLPS) is involved is not known. Here, the authors show the epigenetic reader ZMYND8 forms condensates to deactivate latent SEs in a spatiotemporal manner and thereby restrict macrophage-mediated inflammation.

Discovering common pathogenetic processes between COVID-19 and diabetes mellitus by differential gene expression pattern analysis

Coronavirus disease 2019 (COVID-19) is an infectious disease caused by the newly discovered coronavirus, SARS-CoV-2. Increased severity of COVID-19 has been observed in patients with diabetes mellitus (DM). This study aimed to identify common transcriptional signatures, regulators and pathways between COVID-19 and DM. We have integrated human whole-genome transcriptomic datasets from COVID-19 and DM, followed by functional assessment with gene ontology (GO) and pathway analyses. In peripheral blood mononuclear cells (PBMCs), among the upregulated differentially expressed genes (DEGs), 32 were found to be commonly modulated in COVID-19 and type 2 diabetes (T2D), while 10 DEGs were commonly downregulated. As regards type 1 diabetes (T1D), 21 DEGs were commonly upregulated, and 29 DEGs were commonly downregulated in COVID-19 and T1D. Moreover, 35 DEGs were commonly upregulated in SARS-CoV-2 infected pancreas organoids and T2D islets, while 14 were commonly downregulated. Several GO terms were found in common between COVID-19 and DM. Prediction of the putative transcription factors involved in the upregulation of genes in COVID-19 and DM identified RELA to be implicated in both PBMCs and pancreas. Here, for the first time, we have characterized the biological processes and pathways commonly dysregulated in COVID-19 and DM, which could be in the next future used for the design of personalized treatment of COVID-19 patients suffering from DM as comorbidity.

The β Cell in Diabetes: Integrating Biomarkers With Functional Measures

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

Mesenchymal stem cell-derived exosomal miR-146a reverses diabetic β-cell dedifferentiation

Background

Mesenchymal stem cells (MSCs) show promising therapeutic potential in treating type 2 diabetes mellitus (T2DM) in clinical studies. Accumulating evidence has suggested that the therapeutic effects of MSCs are not due to their direct differentiation into functional β-cells but are instead mediated by their paracrine functions. Among them, exosomes, nano-sized extracellular vesicles, are important substances that exert paracrine functions. However, the underlying mechanisms of exosomes in ameliorating T2DM remain largely unknown.

Methods

Bone marrow mesenchymal stem cell (bmMSC)-derived exosomes (bmMDEs) were administrated to T2DM rats and high-glucose-treated primary islets in order to detect their effects on β-cell dedifferentiation. Differential miRNAs were then screened via miRNA sequencing, and miR-146a was isolated after functional verification. TargetScan, reporter gene detection, insulin secretion assays, and qPCR validation were used to predict downstream target genes and involved signaling pathways of miR-146a.

Results

Our results showed that bmMDEs reversed diabetic β-cell dedifferentiation and improved β-cell insulin secretion both in vitro and in vivo. Results of miRNA sequencing in bmMDEs and subsequent functional screening demonstrated that miR-146a, a highly conserved miRNA, improved β-cell function. We further found that miR-146a directly targeted Numb, a membrane-bound protein involved in cell fate determination, leading to activation of β-catenin signaling in β-cells. Exosomes derived from miR-146a-knockdown bmMSCs lost the ability to improve β-cell function.

Conclusions

These findings demonstrate that bmMSC-derived exosomal miR-146a protects against diabetic β-cell dysfunction by acting on the NUMB/β-catenin signaling pathway, which may represent a novel therapeutic strategy for T2DM.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13287-021-02371-0.

Circulating serum and plasma levels of micro-RNA in type-1 diabetes in children and adolescents: A systematic review and meta-analysis

BACKGROUND

Type 1 diabetes mellitus (T1DM) is a complex metabolic disorder characterized by hyperglycaemia, with constantly increasing incidence in paediatric population. The discovery of new molecules, such as microRNAs, and their possible interactions with T1DM create novel aspects in the diagnosis of the disease.

METHODS

This systematic review and meta-analysis adhered to PRISMA guidelines. MEDLINE, SCOPUS, Cochrane CENTRAL and Clinicaltrials.gov. were searched up to 20 April 2020. Inclusion criteria for individual studies were quantification of microRNAs in serum/plasma samples and study groups consisting of children and adolescents with T1DM and healthy controls. Primary outcome of the study was the qualitative expression of microRNAs between the two groups. Statistical analysis was performed with Comprehensive Meta-Analysis Software v3.0. Methodological quality of included studies was assessed using Newcastle-Ottawa scale.

RESULTS

A total of 484 studies were retrieved from the initial search of the databases. These were subsequently limited to seven included studies. Seven microRNAs demonstrated contrasting expression between the two groups, with two of them showing significant overexpression in T1DM group (miR-181:95% CI: 0.429 to 1.341 P < .001, miR-210:95% CI: 0.381 to 0.852, P < .001) and one micro-RNA being significantly overexpressed in control group (miR-375:95% CI: 0.293 to 1.459, P = .003).

CONCLUSION

A total of three micro-RNA molecules appeared to have a significantly different expression in T1DM patients, serving as a possible diagnostic panel of biomarkers. These findings may contribute as reference for future research to further support the use of microRNAs as a novel diagnostic tool in T1DM.

LncPVT1 promotes cartilage degradation in diabetic OA mice by downregulating miR-146a and activating TGF-β/SMAD4 signaling

INTRODUCTION

To investigate the role of LncRNA PVT1 (plasmacytoma variant translocation 1) in hyperglycemia-triggered cartilage damage using the diabetic osteoarthritis (OA) mice model.

MATERIALS AND METHODS

Streptozotocin (STZ) was used to induce mouse diabetes. Knee OA model was induced through transection of anterior cruciate ligament (ACLT). Severity of arthritis was assessed histologically by Safranin O-Fast Green Staining using Mankin Scores. LncRNA PVT1 and miR-146a were detected by real-time polymerase chain reaction (PCR) in cartilage tissue. Moreover, the interaction among PVT1, miR-146a, and SMAD4 was examined by luciferase reporter assays. Mice were injected intra-articularly with ad-siRNA-PVT1 and ad-siRNA scramble control. Articular concentrations of TNF-α, IL-1, IL-6 and TGF-β1 were determined using enzyme-linked immunosorbent assay. Levels of type II Collagen (COL2A1), TGF-β1, p-SMAD2, SMAD2, p-SMAD3, SMAD3, SMAD4 and nuclear SMAD4 were detected by western blot analysis.

RESULTS

PVT1 expression was significantly increased, whereas miR-146a was markedly decreased in diabetic OA mice than in non-diabetic OA and control. Increased PVT1 expression in diabetic OA mice was significantly associated with Mankin score and reduced miR-146a as well as Collagen alpha-1(II) (COL2A1) expressions. In vivo, intra-articular injection of ad-siRNA-PVT1 efficiently increased miR-146a and COL2A1 expressions, alleviated joint inflammation, decreased the expression of pro-inflammatory mediators, and suppressed TGF-β/SMAD4 pathway in diabetic OA mice.

CONCLUSIONS

Our results demonstrate LncRNA PVT1 is involved in cartilage degradation in diabetic OA and correlated with disease severity. Efficiency of ad-siRNA-PVT1 in controlling joint inflammation in diabetic OA mice is associated with the suppression of the expression of miR-146a, pro-inflammatory cytokines and activation of TGF-β/SMAD4 pathway.

Signature RNAS and related regulatory roles in type 1 diabetes mellitus based on competing endogenous RNA regulatory network analysis

BACKGROUND

Our study aimed to investigate signature RNAs and their potential roles in type 1 diabetes mellitus (T1DM) using a competing endogenous RNA regulatory network analysis.

METHODS

Expression profiles of GSE55100, deposited from peripheral blood mononuclear cells of 12 T1DM patients and 10 normal controls, were downloaded from the Gene Expression Omnibus to uncover differentially expressed long non-coding RNAs (lncRNAs), mRNAs, and microRNAs (miRNAs). The ceRNA regulatory network was constructed, then functional and pathway enrichment analysis was conducted. AT1DM-related ceRNA regulatory network was established based on the Human microRNA Disease Database to carry out pathway enrichment analysis. Meanwhile, the T1DM-related pathways were retrieved from the Comparative Toxicogenomics Database (CTD).

RESULTS

In total, 847 mRNAs, 41 lncRNAs, and 38 miRNAs were significantly differentially expressed. The ceRNA regulatory network consisted of 12 lncRNAs, 10 miRNAs, and 24 mRNAs. Two miRNAs (hsa-miR-181a and hsa-miR-1275) were screened as T1DM-related miRNAs to build the T1DM-related ceRNA regulatory network, in which genes were considerably enriched in seven pathways. Moreover, three overlapping pathways, including the phosphatidylinositol signaling system (involving PIP4K2A, INPP4A, PIP4K2C, and CALM1); dopaminergic synapse (involving CALM1 and PPP2R5C); and the insulin signaling pathway (involving CBLB and CALM1) were revealed by comparing with T1DM-related pathways in the CTD, which involved four lncRNAs (LINC01278, TRG-AS1, MIAT, and GAS5-AS1).

CONCLUSION

The identified signature RNAs may serve as important regulators in the pathogenesis of T1DM.

Quercetin‑conjugated superparamagnetic iron oxide nanoparticles modulate glucose metabolism-related genes and miR-29 family in the hippocampus of diabetic rats

Quercetin (QC) is a dietary bioflavonoid that can be conjugated with nanoparticles to facilitate its brain bioavailability. We previously showed that quercetin-conjugated superparamagnetic iron oxide nanoparticles (QCSPIONs) reduced the level of blood glucose in diabetic rats. Glucose transporters (GLUTs), insulin-like growth factor-1 (IGF-1), and microRNA-29 (miR-29) play a critical role in brain glucose homeostasis. In the current study, we examined the effects of QCSPION on the expression of glucose metabolism-related genes, and the miR-29 family as a candidate regulator of glucose handling in the hippocampus of diabetic rats. Our in silico analyses introduce the miR-29 family as potential regulators of glucose transporters and IGF-1 genes. The expression level of the miR-29 family, IGF-1, GLUT1, GLUT2, GLUT3, and GLUT4 were measured by qPCR. Our results indicate that diabetes significantly results in upregulation of the miR-29 family and downregulation of the GLUT1, 2, 3, 4, and IGF-1 genes. Interestingly, QCSPIONs reduced miR-29 family expression and subsequently enhanced GLUT1, 2, 3, 4, and IGF-1expression. In conclusion, our findings suggest that QCSPION could regulate the expression of the miR-29 family, which in turn increases the expression of glucose transporters and IGF-1, thereby reducing diabetic complications.

Parallel Multi-Omics in High-Risk Subjects for the Identification of Integrated Biomarker Signatures of Type 1 Diabetes

BACKGROUND

Biomarkers are crucial for detecting early type-1 diabetes (T1D) and preventing significant β-cell loss before the onset of clinical symptoms. Here, we present proof-of-concept studies to demonstrate the potential for identifying integrated biomarker signature(s) of T1D using parallel multi-omics.

METHODS

Blood from human subjects at high risk for T1D (and healthy controls; n = 4 + 4) was subjected to parallel unlabeled proteomics, metabolomics, lipidomics, and transcriptomics. The integrated dataset was analyzed using Ingenuity Pathway Analysis (IPA) software for disturbances in the at-risk subjects compared to controls.

RESULTS

The final quadra-omics dataset contained 2292 proteins, 328 miRNAs, 75 metabolites, and 41 lipids that were detected in all samples without exception. Disease/function enrichment analyses consistently indicated increased activation, proliferation, and migration of CD4 T-lymphocytes and macrophages. Integrated molecular network predictions highlighted central involvement and activation of NF-κB, TGF-β, VEGF, arachidonic acid, and arginase, and inhibition of miRNA Let-7a-5p. IPA-predicted candidate biomarkers were used to construct a putative integrated signature containing several miRNAs and metabolite/lipid features in the at-risk subjects.

CONCLUSIONS

Preliminary parallel quadra-omics provided a comprehensive picture of disturbances in high-risk T1D subjects and highlighted the potential for identifying associated integrated biomarker signatures. With further development and validation in larger cohorts, parallel multi-omics could ultimately facilitate the classification of T1D progressors from non-progressors.

Competing endogenous RNA network analysis explores the key lncRNAs, miRNAs, and mRNAs in type 1 diabetes

BACKGROUND

Type 1 diabetes (T1D, named insulin-dependent diabetes) has a relatively rapid onset and significantly decreases life expectancy. This study is conducted to reveal the long non-coding RNA (lncRNA)-microRNA (miRNA)-mRNA regulatory axises implicated in T1D.

METHODS

The gene expression profile under GSE55100 (GPL570 and GPL8786 datasets; including 12 T1D samples and 10 normal samples for each dataset) was extracted from Gene Expression Omnibus database. Using limma package, the differentially expressed mRNAs (DE-mRNAs), miRNAs (DE-miRNAs), and lncRNAs (DE-lncRNAs) between T1D and normal samples were analyzed. For the DE-mRNAs, the functional terms were enriched by DAVID tool, and the significant pathways were enriched using gene set enrichment analysis. The interactions among DE-lncRNAs, DE-miRNAs and DE-mRNAs were predicted using mirwalk and starbase. The lncRNA-miRNA-mRNA interaction network analysis was visualized by Cytoscape. The key genes in the interaction network were verified by quantitatively real-time PCR.

RESULTS

In comparison to normal samples, 236 DE-mRNAs, 184 DE-lncRNAs, and 45 DE-miRNAs in T1D samples were identified. For the 236 DE-mRNAs, 16 Gene Ontology (GO)_biological process (BP) terms, four GO_cellular component (CC) terms, and 57 significant pathways were enriched. A network involving 36 DE-mRNAs, 8 DE- lncRNAs, and 15 DE-miRNAs was built, such as TRG-AS1-miR-23b/miR-423-PPM1L and GAS5-miR-320a/miR-23b/miR-423-SERPINA1 regulatory axises. Quantitatively real-time PCR successfully validated the expression levels of TRG-AS1- miR-23b -PPM1L and GAS5-miR-320a- SERPINA1.

CONCLUSION

TRG-AS1-miR-23b-PPM1L and GAS5-miR-320a-SERPINA1 regulatory axises might impact the pathogenesis of T1D.

microRNA-143-3p contributes to inflammatory reactions by targeting FOSL2 in PBMCs from patients with autoimmune diabetes mellitus

AIM

Autoimmune diabetes mellitus (defined as ADM) comprises classical type 1 diabetes mellitus (T1DM) and latent autoimmune diabetes in adults (LADA). In this study, microRNAs (miRNAs) expression profiles and functions in peripheral blood mononuclear cells (PBMCs) of ADM patients were mapped and used to explore epigenetic regulation of the pathogenesis of ADM.

METHODS

PBMCs samples from T1DM patients, LADA patients, and type 2 diabetes mellitus (T2DM) patients, as well as age- and sex-matched healthy controls for T1DM and T2DM, respectively, were collected and were sequenced to screen the miRNAs expression profiles. The target genes were verified by dual-luciferase reporter assay. Silencing or overexpressing of the differentially expressed miRNAs, or simultaneously silencing the miRNAs and it's target gene, and then levels of the mRNAs, protein and cytokines were detected.

RESULTS

miR-143-3p expression was upregulated in ADM patients. The target gene of miR-143-3p was identified as Fos-related antigen 2 (FOSL2). Transfection of a miR-143-3p inhibitor into PBMCs upregulated FOSL2 expression, resulting in a downregulated expression of the IL-2, TNF-α, and IFN-γ, and an upregulated expression of IL-6. Transfection of a miR-143-3p mimic into PBMCs downregulated FOSL2 expression, leading to an upregulation of IL-2 and TNF-α expression and a downregulation of IL-6 expression. When silencing FOSL2 while inhibiting miR-143-3p in PBMCs, there was no significant change in expression of the FOSL2 mRNA, protein and cytokines.

CONCLUSION

The expression of miR-143-3p in PBMCs from ADM patients is upregulated. miR-143-3p could function in the pathogenesis of ADM by modulating the inflammatory reaction through FOSL2.

Cell-free nucleic acid patterns in disease prediction and monitoring-hype or hope?

Interest in the use of cell-free nucleic acids (CFNAs) as clinical non-invasive biomarker panels for prediction and prevention of multiple diseases has greatly increased over the last decade. Indeed, circulating CFNAs are attributable to many physiological and pathological processes such as imbalanced stress conditions, physical activities, extensive apoptosis of different origin, systemic hypoxic-ischemic events and tumour progression, amongst others. This article highlights the involvement of circulating CFNAs in local and systemic processes dealing with the question, whether specific patterns of CFNAs in blood, their detection, quantity and quality (such as their methylation status) might be instrumental to predict a disease development/progression and could be further utilised for accompanying diagnostics, targeted prevention, creation of individualised therapy algorithms, therapy monitoring and prognosis. Presented considerations conform with principles of 3P medicine and serve for improving individual outcomes and cost efficacy of medical services provided to the population.

Non-canonical Interaction Between O-Linked N-Acetylglucosamine Transferase and miR-146a-5p Aggravates High Glucose-Induced Endothelial Inflammation

Background and Aims: Increased O-GlcNAc transferase (OGT)–induced O-linked N-acetylglucosamine (O-GlcNAc) post-translational modification is linked with diabetic complications. MicroRNA-146a-5p (miR-146a-5p) is a negative inflammatory regulator and is downregulated in diabetes. Here, we investigated the interaction between miR-146a-5p and OGT.

Methods: Human aortic endothelial cells (HAECs) were stimulated with high glucose (25 mM) and glucosamine (25 mM) for 24 h. Western blot, real time PCR, bioinformatics analysis, luciferase reporter assay, miR-146a-5p mimic/inhibitor transfection, siRNA OGT transfection, miR-200a/200b mimic transfection, and OGT pharmacological inhibition (ST045849) were performed. The aorta from miR-146a-5p mimic-treated db/db mice were examined by immunohistochemistry staining.

Results: HG and glucosamine upregulated OGT mRNA and protein expression, protein O-GlcNAcylation, and IL-6 mRNA and protein expression. Real time PCR analysis found that miR-146a-5p was decreased in HG- and glucosamine-stimulated HAECs. This suggested that OGT-induced protein O-GlcNAcylation as a mechanism to downregulate miR-146a-5p. Bioinformatic miR target analysis excluded miR-146a-5p as a post-transcriptional regulator of OGT. However, a luciferase reporter assay confirmed that miR-146a-5p mimic bound to 3′-UTR of human OGT mRNA, indicating that OGT is a non-canonical target of miR-146a-5p. Transfection with miR-146a-5p mimic and inhibitor confirmed that miR-146a-5p regulated OGT/protein O-GlcNAcylation/IL-6 expression levels. Furthermore, OGT siRNA transfection, miR-200a/miR-200b mimic transfection, and ST045849 increased HG-induced miR-146a-5p expression levels, indicating that HG-induced miR-146a-5p downregulation is partially mediated through OGT-mediated protein O-GlcNAcylation. In vivo, intravenous injections of miR-146a mimic decreased endothelial OGT and IL6 expression in db/db mice.

Conclusion: A non-canonical positive feedback interaction between miR-146a-5p and OGT is involved in a vicious cycle to aggravate HG-induced vascular complications.

Effects of troxerutin on vascular inflammatory mediators and expression of microRNA-146a/NF-κB signaling pathway in aorta of healthy and diabetic rats

This study has investigated the effect of a potent bioflavonoid, troxerutin, on diabetes-induced changes in pro-inflammatory mediators and expression of microRNA-146a and nuclear factor-kappa-B (NF-κB) signaling pathway in aortic tissue of type-I diabetic rats. Male Wistar rats were randomly divided into four groups (n = 6/each): healthy, healthy-troxerutin, diabetic, and diabetic-troxerutin. Diabetes was induced by streptozotocin injection (60 mg/kg; intraperitoneally) and lasted 10 weeks. Troxerutin (150 mg/kg/day) was administered orally for last month of experiment. Inflammatory cytokines IL-1β, IL-6, and TNF-α, as well as intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule (VCAM), cyclooxygenase-II (COX-II), and inducible-nitric oxide synthase (iNOS) were measured on aortic samples by enzyme-linked immunosorbent assay. Gene expressions for transcription factor NF-κB, interleukin-1 receptor-associated kinase-1 (IRAK-1), TNF receptor-associated factor-6 (TRAF-6), and microRNA-146a were determined using real-time polymerase chain reaction. Ten-week diabetes significantly increased mRNA levels of IRAK-1, TRAF-6, NF-κB, and protein levels of cytokines IL-1β, IL-6, TNF-α, adhesion molecules ICAM-1, VCAM, and iNOS, COX-II, and decreased expression of microRNA-146a as compared with healthy rats (p < 0.05 to p < 0.01). However, one month treatment of diabetic rats with troxerutin restored glucose and insulin levels, significantly decreased expression of inflammatory genes and pro-inflammatory mediators and increased microRNA level in comparison to diabetic group (p < 0.05 to p < 0.01). In healthy rats, troxerutin had significant reducing effect only on NF-κB, TNF-α and COX-II levels (p < 0.05). Beside slight improvement of hyperglycemia, troxerutin prevented the activation of NF-κB-dependent inflammatory signaling in the aorta of diabetic rats, and this response may be regulated by microRNA-146a.

Association of miR-146a polymorphism rs2910164 and type 2 diabetes risk: a meta-analysis

OBJECTIVE

Circulating miR-146a is aberrantly expressed in patients with type 2 diabetes (T2D), probably resulting from gene polymorphisms. However, the role of polymorphism rs2910164 in T2D pathogenesis remains controversial. Thus, we designed a meta-analysis to investigate the association between rs2910164 and T2D.

METHODS

PubMed and Embase were searched for eligible papers in English published through September 2, 2019. Random or fixed effect models were used to determine risk estimates according to heterogeneities.

RESULTS

Four studies, involving 2,069 patients and 1,950 controls, were included. Odds ratios (ORs) and 95% confidence intervals (95% CIs) were used to pool the effect size. The pooled ORs and 95% CIs were 1.501 (0.887-2.541), 1.102 (0.931-1.304), 1.276 (0.900-1.811), 1.204 (0.878-1.652), 1.238 (0.880-1.740), and 1.350 (0.904-2.016) under the homozygote, heterozygote (CG vs. GG and CC vs. CG), dominant, allele, and recessive models, respectively. Heterogeneity was detected in most genetic models, with subgroup analyses performed by ethnicity, genotyping method, and disease duration. The co-dominant model was determined to be the most appropriate genetic model.

CONCLUSIONS

Our findings suggested that polymorphism rs2910164 is not correlated with T2D susceptibility. However, the results should be interpreted with caution because of confounding factors.

A comprehensive review on miR-146a molecular mechanisms in a wide spectrum of immune and non-immune inflammatory diseases

MicroRNAs (miRNAs) are single-strand endogenous and non-coding RNA molecules with a length of about 22 nucleotides, which regulate genes expression, through modulating the translation and stability of their target mRNAs. miR-146a is one of the most studied miRNAs, due to its central role in immune system homeostasis and control of the innate and acquired immune responses. Accordingly, abnormal expression or function of miR-146a results in the incidence and progression of immune and non-immune inflammatory diseases. Its deregulated expression pattern and inefficient function have been reported in a wide spectrum of these illnesses. Based on the existing evidence, this miRNA qualifies as an ideal biomarker for diagnosis, prognosis, and activity evaluation of immune and non-immune inflammatory disorders. Moreover, much attention has recently been paid to therapeutic potential of miR-146a and several researchers have assessed the effects of different drugs on expression and function of this miRNA at diverse experimental, animal, besides human levels, reporting motivating results in the treatment of the diseases. Here, in this comprehensive review, we provide an overview of miR-146a role in the pathogenesis and progression of several immune and non-immune inflammatory diseases such as Rheumatoid arthritis, Systemic lupus erythematosus, Inflammatory bowel disease, Multiple sclerosis, Psoriasis, Graves' disease, Atherosclerosis, Hepatitis, Chronic obstructive pulmonary disease, etc., discuss about its eligibility for being a desirable biomarker for these disorders, and also highlight its therapeutic potential. Understanding these mechanisms underlies the selecting and designing the proper therapeutic targets and medications, which eventually facilitate the treatment process.

miRNA Regulation of T Cells in Islet Autoimmunity and Type 1 Diabetes

PURPOSE OF REVIEW

Regulatory T cells (Tregs) are critical contributors to immune homeostasis and their dysregulation can lead to the loss of immune tolerance and autoimmune diseases like type 1 diabetes (T1D). Recent studies have highlighted microRNAs (miRNAs) as important regulators of the immune system, by fine-tuning relevant genes in various immune cell types. In this review article, we discuss recent insights into miRNA regulation of immune tolerance and activation. Specifically, we discuss how the dysregulation of miRNAs in T cells contributes to their aberrant function and the onset of islet autoimmunity, as well as their potential as targets of novel intervention strategies to interfere with autoimmune activation.

RECENT FINDINGS

Several studies have shown that the dysregulation of individual miRNAs in T cells can contribute to impaired immune tolerance, contributing to onset and progression of islet autoimmunity. Importantly, the targeting of these miRNAs, including miR-92a, miR-142-3p and miR-181a, resulted in relevant effects on downstream pathways, improved Treg function and reduced islet autoimmunity in murine models. miRNAs are critical regulators of immune homeostasis and the dysregulation of individual miRNAs in T cells contributes to aberrant T cell function and autoimmunity. The specific targeting of individual miRNAs could improve Treg homeostasis and therefore limit overshooting T cell activation and islet autoimmunity.

Identification of key genes for type 1 diabetes mellitus by network-based guilt by association

OBJECTIVE This study aimed to propose a co-expression-network (CEN) based gene functional inference by extending the "Guilt by Association" (GBA) principle to predict candidate gene functions for type 1 diabetes mellitus (T1DM). METHODS Firstly, transcriptome data of T1DM were retrieved from the genomics data repository for differentially expressed gene (DEGs) analysis, and a weighted differential CEN was generated. The area under the receiver operating characteristics curve (AUC) was chosen to determine the performance metric for each Gene Ontology (GO) term. Differential expression analysis identified 325 DEGs in T1DM, and co-expression analysis generated a differential CEN of edge weight > 0.8. RESULTS A total of 282 GO annotations with DEGs > 20 remained for functional inference. By calculating the multifunctionality score of genes, gene function inference was performed to identify the optimal gene functions for T1DM based on the optimal ranking gene list. Considering an AUC > 0.7, six optimal gene functions for T1DM were identified, such as regulation of immune system process and receptor activity. CONCLUSIONS CEN-based gene functional inference by extending the GBA principle predicted 6 optimal gene functions for T1DM. The results may be potential paths for therapeutic or preventive treatments of T1DM.

Identification of a Multi-Long Noncoding RNA Signature for the Diagnosis of Type 1 Diabetes Mellitus

Due to the increasing prevalence of type 1 diabetes mellitus (T1DM) and its complications, there is an urgent need to identify novel methods for predicting the occurrence and understanding the pathogenetic mechanisms of the disease. Accumulated data have demonstrated the potential of long noncoding RNAs (lncRNAs), as biomarkers in establishing diagnosis and predicting prognosis of numerous diseases. Yet, little is known about the expression patterns and regulatory roles of lncRNAs in the pathogenesis of T1DM and whether they can be used as diagnostic biomarkers for the disease. To further explore these questions, in the present study, we conducted a comparative analysis of the expression patterns of lncRNAs between 20 T1DM patients and 42 health controls by retrospectively analyzing a published microarray data set. Our results indicate that, compared with healthy controls, diabetic patients had altered levels of lncRNAs. Then, we used three time cross-validation strategy and support vector machine to propose a specific 26-lncRNA signature (termed 26LncSigT1DM). This 26LncSigT1DM signature can be used to effectively distinguish between healthy and diabetic individuals (area under the curve = 0.825) of a validation cohort. After the 26LncSigT1DM was prospectively validated, we used Pearson correlation to identify 915 mRNAs, whose expression levels were positively correlated with those of the 26 lncRNAs. According to their Gene Ontology annotations, these mRNAs participate in processes including cellular response to stimulus, cell communication, multicellular organismal process, and cell motility. Kyoto Encyclopedia of Genes and Genomes analysis demonstrated that the genes encoding the 915 mRNAs may be associated with the NOD-like receptor signaling pathway, transforming growth factor β signaling pathway, and mineral absorption, suggesting that the deregulation of these lncRNAs may mediate inflammatory abnormalities and immune dysfunctions, which jointly promote the pathogenesis of T1DM. Thus, our study identifies a novel diagnostic tool and may shed more light on the molecular mechanisms underlying the pathogenesis of T1DM.

Innate Viral Sensor MDA5 and Coxsackievirus Interplay in Type 1 Diabetes Development

Type 1 diabetes (T1D) is a polygenic autoimmune disease characterized by immune-mediated destruction of insulin-producing β-cells. The concordance rate for T1D in monozygotic twins is ≈30-50%, indicating that environmental factors also play a role in T1D development. Previous studies have demonstrated that enterovirus infections such as coxsackievirus type B (CVB) are associated with triggering T1D. Prior to autoantibody development in T1D, viral RNA and antibodies against CVB can be detected within the blood, stool, and pancreata. An innate pathogen recognition receptor, melanoma differentiation-associated protein 5 (MDA5), which is encoded by the IFIH1 gene, has been associated with T1D onset. It is unclear how single nucleotide polymorphisms in IFIH1 alter the structure and function of MDA5 that may lead to exacerbated antiviral responses contributing to increased T1D-susceptibility. Binding of viral dsRNA via MDA5 induces synthesis of antiviral proteins such as interferon-alpha and -beta (IFN-α/β). Viral infection and subsequent IFN-α/β synthesis can lead to ER stress within insulin-producing β-cells causing neo-epitope generation, activation of β-cell-specific autoreactive T cells, and β-cell destruction. Therefore, an interplay between genetics, enteroviral infections, and antiviral responses may be critical for T1D development.

Molecular biomarkers in diabetes mellitus (DM)

Background: Diabetes mellitus (DM) is a growing epidemic metabolic syndrome, which affects near 5.6% of the world's population. Almost 12% of health expenditure is dedicated to this disorder. Discovering and developing biomarkers as a practical guideline with high specificity and sensitivity for the diagnosis, prognosis, and clinical management of DM is one of the subjects of great interest among DM researchers due to the long-lasting asymptomatic clinical manifestation of DM. In this study, we described a recently identified molecular biomarker involved in DM. Methods: This review study was done at the Diabetes Research Center affiliated to Shahid Sadoughi University of Medical Sciences. PubMed, Scopus, Google Scholar, and Web of Science were searched using the following keywords: "diabetes mellitus", "biomarker", "microRNA", "diagnostic tool" and "clinical manifestation." Results: A total of 107 studies were finally included in this review. After evaluating numerous articles, including original, metaanalysis, and review studies, we focused on molecular biomarkers involved in DM diagnosis and management. Conclusion: Increasing interest in biomarkers associated with DM goes back to its role in decreasing diabetes-related morbidity and mortality. This review focused on major molecular biomarkers such as proteomic and microRNA (miRNAs) as novel and interesting DM biomarkers that can help achieve timely diagnosis of DM.

Analysis of potential hub genes involved in the pathogenesis of Chinese type 1 diabetic patients

Background

Type 1 diabetes is an autoimmune disease strongly related to genetic factors. Although studies on T1D susceptibility genes have achieved great progress, the molecular mechanism of T1D remains to be explained.

Methods

To explore the underlying mechanisms of T1D, bioinformatic analysis based on a microarray database was used to determine the key biomarkers of T1D as well as their biofunctions and interactions. The microarray database GSE55100 was downloaded from the Gene Expression Omnibus (GEO). Differentially expressed genes (DEGs) were processed by packages in R Software. The database for Annotation, Visualization, and Integrated Discovery (DAVID, version 6.8) was used to conduct gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses. The protein-protein interaction network was analyzed with the Search Tool for the Retrieval of Interacting Genes (STRING), and the module analysis was performed using Cytoscape.

Results

Seventy-eight DEGs and 13 hub genes were identified. The biofunctions and pathways of these DEGs were enriched in immune response, extracellular exosome, cytokine activity and antigen processing and presentation. Thirteen DEGs with MCODE score ≥2 were selected as hub genes including MMP9, ARG1, CAMP, CHI3L1, CRISP3, SLPI, LCN2, PGLYRP1, LTF, RETN, CEACAM1, CEACAM8 and MS4A3.

Conclusions

The identification and analyses of the DEGs and hub genes from database GSE55100 provide novel prospectives of the pathogenesis of T1D.

In silico transcriptional analysis of mRNA and miRNA reveals unique biosignatures that characterizes different types of diabetes

Diabetes (DM) has a significant impact on public health. We performed an in silico study of paired datasets of messenger RNA (mRNA) micro-RNA (miRNA) transcripts to delineate potential biosignatures that could distinguish prediabetes (pre-DM), type-1DM (T1DM) and type-2DM (T2DM). Two publicly available datasets containing expression values of mRNA and miRNA obtained from individuals diagnosed with pre-DM, T1DM or T2DM, and normoglycemic controls (NC), were analyzed using systems biology approaches to define combined signatures to distinguish different clinical groups. The mRNA profile of both pre-DM and T2DM was hallmarked by several differentially expressed genes (DEGs) compared to NC. Nevertheless, T1DM was characterized by an overall low number of DEGs. The miRNA signature profiles were composed of a substantially lower number of differentially expressed targets. Gene enrichment analysis revealed several inflammatory pathways in T2DM and fewer in pre-DM, but with shared findings such as Tuberculosis. The integration of mRNA and miRNA datasets improved the identification and discriminated the group composed by pre-DM and T2DM patients from that constituted by normoglycemic and T1DM individuals. The integrated transcriptomic analysis of mRNA and miRNA expression revealed a unique biosignature able to characterize different types of DM.

miR-409-3p is reduced in plasma and islet immune infiltrates of NOD diabetic mice and is differentially expressed in people with type 1 diabetes

AIMS/HYPOTHESIS

MicroRNAs (miRNAs) are a novel class of potential biomarkers emerging in many diseases, including type 1 diabetes. Here, we aim to analyse a panel of circulating miRNAs in non-obese diabetic (NOD) mice and individuals with type 1 diabetes.

METHODS

We adopted standardised methodologies for extracting miRNAs from small sample volumes to evaluate a profiling panel of mature miRNAs in paired plasma and laser-captured microdissected immune-infiltrated islets of recently diabetic and normoglycaemic NOD mice. Moreover, we validated the findings during disease progression and remission after anti-CD3 therapy in NOD mice, as well as in individuals with type 1 diabetes.

RESULTS

Plasma levels of five miRNAs were downregulated in diabetic vs normoglycaemic mice. Of those, miR-409-3p was also downregulated in situ in the immune islet infiltrates of diabetic mice, suggesting an association with disease pathogenesis. Target-prediction tools linked miR-409-3p to immune- and metabolism-related signalling molecules. In situ miR-409-3p expression correlated with insulitis severity, and CD8⁺ central memory T cells were found to be enriched in miR-409-3p. Plasma miR-409-3p levels gradually decreased during diabetes development and improved with disease remission after anti-CD3 antibody therapy. Finally, plasma miR-409-3p levels were lower in people recently diagnosed with type 1 diabetes compared with a non-diabetic control group, and levels were inversely correlated with HbA_1c levels.

CONCLUSIONS/INTERPRETATION

We propose that miR-409-3p may represent a new circulating biomarker of islet inflammation and type 1 diabetes severity.

miRNA-Mediated Immune Regulation in Islet Autoimmunity and Type 1 Diabetes

The important role of microRNAs as major modulators of various physiological processes, including immune regulation and homeostasis, has been increasingly recognized. Consequently, aberrant miRNA expression contributes to the defective regulation of T cell development, differentiation, and function. This can result in immune activation and impaired tolerance mechanisms, which exert a cardinal function for the onset of islet autoimmunity and the progression to T1D. The specific impact of miRNAs for immune regulation and how miRNAs and their downstream targets are involved in the pathogenesis of islet autoimmunity and T1D has been investigated recently. These studies revealed that increased expression of individual miRNAs is involved in several layers of tolerance impairments, such as inefficient Treg induction and Treg instability. The targeted modulation of miRNAs using specific inhibitors, resulting in improved immune homeostasis, as well as improved methods for the targeting of miRNAs, suggest that miRNAs, especially in T cells, are a promising target for the reestablishment of immune tolerance.

The Role of Epigenetics in Type 1 Diabetes

Type 1 diabetes (T1D) is an autoimmune disease caused by the interaction between genetic alterations and environmental factors. More than 60 susceptible genes or loci of T1D have been identified. Among them, HLA regions are reported to contribute about 50% of genetic susceptibility in Caucasians. There are many environmental factors involved in the pathogenesis of T1D. Environmental factors may change the expression of genes through epigenetic mechanisms, thus inducing individuals with susceptible genes to develop T1D; however, the underlying mechanisms remain poorly understood. The major epigenetic modifications include DNA methylation, histone modification, and non-coding RNA. There has been extensive research on the role of epigenetic mechanisms including aberrant DNA methylation, histone modification, and microRNA in the pathogenesis of T1D. DNA methylation and microRNA have been proposed as biomarkers to predict islet β cell death, which needs further confirmation before any clinical application can be developed. Small molecule inhibitors of histone deacetylases, histone methylation, and DNA methylation are potentially important for preventing T1D or in the reprogramming of insulin-producing cells. This chapter mainly focuses on T1D-related DNA methylation, histone modification, and non-coding RNA, as well as their possible translational potential in the early diagnosis and treatment of T1D.

Dysregulation of Inflammasome Priming and Activation by MicroRNAs in Human Immune-Mediated Diseases

Inflammasomes are protein complexes that respond to a wide range of pathogens and cellular damage signals. Their activation prompts the caspase-1-mediated cleavage of the proinflammatory cytokines IL-1β and IL-18. Inflammasome dysregulation has been demonstrated to play a role in a range of diseases involving the adaptive immune system like multiple sclerosis, rheumatic diseases, and type 1 diabetes. Priming and activation of inflammasomes can be modulated by microRNAs (miRNAs), small noncoding RNAs that regulate gene expression posttranscriptionally. miRNAs, such as miR-223-3p, have been demonstrated to directly target the inflammasome components NLRP3, caspase-1, and caspase-8. Other miRNAs like miR-155-5p modulate TLR-, IL-1R-, TNFR-, and IFNAR-mediated signaling pathways upstream of the inflammasomes. In this study, we discuss how a more detailed elucidation of miRNA-driven inflammasome regulation helps in understanding the molecular processes underlying immune-mediated human diseases, holds potential for the identification of biomarkers and may offer novel targets for the development of future therapeutics.

Epigenetic Regulation in Etiology of Type 1 Diabetes Mellitus

Type 1 diabetes mellitus (T1DM) is caused by an autoimmune destruction of the pancreatic β-cells, a process in which autoreactive T cells play a pivotal role, and it is characterized by islet autoantibodies. Consequent hyperglycemia is requiring lifelong insulin replacement therapy. T1DM is caused by the interaction of multiple environmental and genetic factors. The integrations of environments and genes occur via epigenetic regulations of the genome, which allow adaptation of organism to changing life conditions by alternation of gene expression. T1DM has increased several-fold over the past half century. Such a short time indicates involvement of environment factors and excludes genetic changes. This review summarizes the most current knowledge of epigenetic changes in that process leading to autoimmune diabetes mellitus.

Omics-based biomarkers in the diagnosis of diabetes

Diabetes mellitus (DM) is a group of metabolic diseases related to the dysfunction of insulin, causing hyperglycaemia and life-threatening complications. Current early screening and diagnostic tests for DM are based on changes in glucose levels and autoantibody detection. This review evaluates recent studies on biomarker candidates in diagnosing type 1, type 2 and gestational DM based on omics classification, whilst highlighting the relationship of these biomarkers with the development of diabetes, diagnostic accuracy, challenges and future prospects. In addition, it also focuses on possible non-invasive biomarker candidates besides common blood biomarkers.

The role of T cell miRNAs for regulatory T cell induction in islet autoimmunity

BACKGROUND

microRNAs (miRNAs) have emerged as critical contributors to immune regulation and homeostasis, and their dysregulation is involved in the aberrant differentiation and function of T cell subsets. In type 1 diabetes (T1D), the clinically overt disease is preceded by a presymptomatic phase which is marked by the presence of islet autoantibodies while the individual is still normoglycemic. Recent analyses revealed impaired regulatory T (Treg) cell induction from naive CD4+ T cells during this early phase of autoimmunity.

SCOPE OF THE REVIEW

In this review article, we aim to discuss important recent insights into miRNA regulation of immune homeostasis and activation. Specifically, we highlight the role of miRNAs as biomarkers in autoimmunity and T1D as well as the contribution of specific miRNAs and their downstream pathways to the onset and progression of islet immunity. Furthermore, we focus on critical next steps required to establish miRNAs as biomarkers to predict disease onset and progression and as novel targets of future prevention and treatment strategies to control autoimmunity.

MAJOR CONCLUSIONS

Several recent studies have provided considerable insight into the miRNA regulation of immune homeostasis and how dysregulated miRNAs contribute to onset and progression of islet autoimmunity. Specifically, high levels of individual miRNAs such as miR92a and miR181a are involved in impaired Treg induction during the onset of islet autoimmunity, thereby contributing to disease pathogenesis. The recent advancements in the field suggest miRNAs as potential biomarkers for islet autoimmunity and their direct targeting, especially in a T cell-specific manner, could contribute to the reestablishment of immune homeostasis and ultimately interfere with the onset of islet autoimmunity.