Functional Role of miR-155 in the Pathogenesis of Diabetes Mellitus and Its Complications

Effects of Phytochemicals on Type 2 Diabetes via MicroRNAs

PURPOSE OF REVIEW

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

RECENT FINDINGS

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

Dietary modulation of microRNAs in insulin resistance and type 2 diabetes

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

The Interplay Between Cytokines and MicroRNAs to Regulate Metabolic Disorders

Metabolic disorders represent significant public health challenges worldwide. Emerging evidence suggests that cytokines and microRNAs (miRNAs) play crucial roles in the pathogenesis of metabolic disorders by regulating various metabolic processes, including insulin sensitivity, lipid metabolism, and inflammation. This review provides a comprehensive overview of the intricate interplay between cytokines and miRNAs in the context of metabolic disorders, including obesity, type 2 diabetes, and cardiovascular diseases. We discuss how dysregulation of cytokine-miRNA networks contributes to the development and progression of metabolic disorders and explore the therapeutic potential of targeting these interactions for disease management.

Role of Decreased Expression of miR-155 and miR-146a in Peripheral Blood of Type 2 Diabetes Mellitus Patients with Diabetic Peripheral Neuropathy

Objective

To Study the Correlations of microRNA-155 (miR-155) and microRNA-146a (miR-146a) Expression in Peripheral Blood of Type 2 Diabetes Mellitus (T2DM) Patients with Diabetic Peripheral Neuropathy (DPN), and Explore the Clinical Value of miR-155 and miR-146a in the Diagnosis and Treatment Outcomes of DPN.

Methods

The study included 51 T2DM patients without DPN (T2DM group), 49 T2DM patients with DPN (DPN group), and 50 normal controls (NC group). Quantitative real-time PCR was utilized to determine the expression levels of miR-155 and miR-146a. Clinical features and risk factors for DPN were assessed. Multivariate stepwise logistic regression analysis was conducted to confirm whether the expressions of miR-155 and miR-146a could independently predict the risk of DPN. ROC curve analysis evaluated their diagnostic value.

Results

The T2DM group exhibited significantly lower expression levels of miR-155 and miR-146a compared to the NC group (P < 0.05). Moreover, the DPN group exhibited a significantly decreased expression level of miR-155 and miR-146a compared to the T2DM group (P < 0.01). Multivariate logistic regression analysis indicated that higher levels of miR-155 and miR-146a might serve as protective factors against DPN development. ROC curve analysis revealed that miR-155 (sensitivity 91.8%, specificity 37.3%, AUC 0.641,) and miR-146a (sensitivity 57.1%, specificity 84.3%, AUC 0.722) possess a strong ability to discriminate between T2DM and DPN. Their combined use further enhanced the diagnostic potential of DPN (sensitivity 83.7%, specificity 60.8%, AUC 0.775). A multi-index combination can improve DPN diagnostic efficiency.

Conclusion

The decreased expression of miR-155 and miR-146a in the peripheral blood of T2DM patients is closely related to the occurrence of DPN, highlighting their potential as valuable biomarkers for diagnosing and prognosticating DPN.

First-Trimester Plasmatic microRNAs Are Associated with Fasting Glucose Levels in Late Second Trimester of Pregnancy

Maternal blood glucose regulation adaptation to pregnancy aims to support fetal growth but may also lead to the development of gestational diabetes mellitus, the most common pregnancy complication. MiRNAs are small RNA molecules secreted and stable in the blood, where they could have paracrine hormone-like functions (ribo-hormone) and regulate metabolic processes including fetal growth and glucose metabolism. The objective of this study was to identify plasmatic microRNA (miRNAs) measured during the first trimester of pregnancy that were associated with glucose levels during a 75 g oral glucose tolerance test (OGTT) at ~26 weeks of pregnancy. miRNAs were quantified using next-generation sequencing in 444 pregnant women and replicated in an independent cohort of 106 pregnant women. MiRNAs associated with glucose levels were identified with the DESeq2 package. We identified 24 miRNAs associated with fasting glycemia, of which 18 were common to both cohorts (q-value < 0.1). However, no association was found between miRNAs and 1 h or 2 h post OGTT glycemia. To conclude, we identified 18 miRNAs early in pregnancy that were associated with fasting blood glucose measured 3 months later. Our findings offer new insights into the mechanisms involved in fasting glucose homeostasis regulation in pregnancy, which is critical to understanding how gestational diabetes develops.

High stress hyperglycemia ratio predicts adverse clinical outcome in patients with coronary three-vessel disease: a large-scale cohort study

BACKGROUND

Coronary three-vessel disease (CTVD) accounts for one-third of the overall incidence of coronary artery disease, with heightened mortality rates compared to single-vessel lesions, including common trunk lesions. Dysregulated glucose metabolism exacerbates atherosclerosis and increases cardiovascular risk. The stress hyperglycemia ratio (SHR) is proposed as an indicator of glucose metabolism status but its association with cardiovascular outcomes in CTVD patients undergoing percutaneous coronary intervention (PCI) remains unclear.

METHODS

10,532 CTVD patients undergoing PCI were consecutively enrolled. SHR was calculated using the formula: admission blood glucose (mmol/L)/[1.59×HbA1c (%)-2.59]. Patients were divided into two groups (SHR Low and SHR High) according to the optimal cutoff value of SHR. Multivariable Cox regression models were used to assess the relationship between SHR and long-term prognosis. The primary endpoint was cardiovascular (CV) events, composing of cardiac death and non-fatal myocardial infarction (MI).

RESULTS

During the median follow-up time of 3 years, a total of 279 cases (2.6%) of CV events were recorded. Multivariable Cox analyses showed that high SHR was associated with a significantly higher risk of CV events [Hazard Ratio (HR) 1.99, 95% Confidence interval (CI) 1.58-2.52, P < 0.001). This association remained consistent in patients with (HR 1.50, 95% CI 1.08-2.10, P = 0.016) and without diabetes (HR 1.97, 95% CI 1.42-2.72, P < 0.001). Additionally, adding SHR to the base model of traditional risk factors led to a significant improvement in the C-index, net reclassification and integrated discrimination.

CONCLUSIONS

SHR was a significant predictor for adverse CV outcomes in CTVD patients with or without diabetes, which suggested that it could aid in the risk stratification in this particular population regardless of glucose metabolism status.

The Evaluation of a 5-miRNA Panel in Patients with Periodontitis Disease

INTRODUCTION

Side by side with tooth decay, periodontitis remains one of the most common oral diseases and is increasingly recognized as a serious public health concern worldwide.

OBJECTIVES

The present study aims at comparing the levels of 5 specific miRNAs (miR-29b-3p, miR-34a-5p, miR-155-5p, miR-181a-5p, and miR-192-5p) in patients with periodontal disease and healthy controls.

METHODS

The pathogenic mechanism is related to the activation of immune response and significant alteration of coding and noncoding genes, including miRNA. The study includes 50 subjects (17 with periodontal disease and 33 healthy controls) with a mean age of 45.3 y. In both periodontitis patients and healthy controls, a panel of 5 miRNAs (miR-29b-3p, miR-34a-5p, miR-155-5p, miR-181a-5p, and miR-192-5p) is examined by determining their expression levels with quantitative reverse transcription polymerase chain reaction.

RESULTS

The periodontitis patients express high levels of all the investigated miRNAs. Receiver operating characteristic curve analysis shows an area under the curve (AUC) of 0.69 to 0.74 for individual transcripts with the highest AUC value observed for miR-192, followed by miR-181a.

CONCLUSIONS

The study indicates that the 5-miRNA panel can be used as biomarker for periodontitis. In this way, all implantology procedures and treatment options for patients diagnosed with periodontitis can be improved for better long-term results, predictability, and follow-up frequency.

KNOWLEDGE TRANSFER STATEMENT

The discovery of a miRNA panel as a potential biomarker for periodontitis offers major opportunities for practical application. Our study can improve diagnostic accuracy; researchers can develop new theories on molecular mechanisms and biomarker discovery.

Role of microRNAs in Diabetes-Associated Periodontitis: A Scoping Review

Aim

Diabetes mellitus (DM), a metabolic disorder, exhibits a bidirectional relationship with periodontitis (PD), and recently, microRNAs (miRNAs) were associated with their progression. This review aims to assess the role of miRNAs in the pathogenesis of DM-associated PD and their plausible application as a biomarker for PD in individuals with DM.

Materials and Methods

The search conducted until September 2023 on Medline (Pubmed), Scopus, Embase, and Web of Science using the keywords "microRNA," "miRNA," or "miR," combined with "Diabetes" and "PD" yielded 100 articles. Only research focusing on the role of miRNAs in the pathogenesis of DM-associated PD and their potential application as biomarkers for both conditions were included. Finally, 14 studies were assessed for any bias, and the collected data included study design, sample size, participant groups, age, sample obtained, PD severity, miRNAs examined, clinical and biochemical parameters related to DM and PD, and primary outcomes.

Results

In vivo studies indicated altered expression of miRNAs-146a, -146b, -155, -200b, -203, and -223, specifically in the comorbid subjects with both conditions. Animal, ex vivo, and in vitro studies demonstrated altered expression of miRNAs-126, -147, -31, -25-3p, -508-3p, -214, 124-3p, -221, -222, and the SIRT6-miR-216/217 axis. These miRNAs impact innate and adaptive immune mechanisms, oxidative stress, hyperglycemia, and insulin sensitivity, thereby promoting periodontal destruction in DM. miRNA-146a emerges as a reliable biomarker of PD in DM, whereas miRNA-155 is a consistent predictor of PD in subjects without DM.

Conclusions

miRNAs exert influence on immuno-inflammation in DM-associated PD. Although they can be biomarkers of PD and DM, their clinical utility is hindered by the absence of standardized tests to evaluate their sensitivity and specificity. Moreover, there has been limited exploration of the role of miRNAs in DM-associated PD through human studies. Future clinical trials are warranted to address this gap, focusing on standardizing sample collection, miRNA sources, and detection methods. This approach will enable the identification of specific miRNAs for DM-associated PD.

Impact of Combined Aerobic Training and Magnesium Supplementation on Serum Biomarkers and microRNA-155 and microRNA-21 Expression in Adipose Tissue of Type 2 Diabetic Rats: An Eight-Week Interventional Study

BACKGROUND

Type 2 diabetes mellitus (T2DM) is a complex metabolic disorder characterized by insulin resistance and chronic inflammation. Aerobic training (AT) and magnesium supplementation (Mg) have both been independently shown to have beneficial effects on glucose control and insulin sensitivity in individuals with T2DM. However, the potential synergistic effects of combining AT and Mg supplementation have not been extensively studied. This study aimed to investigate the effects of an 8-week AT and Mg supplementation on serum levels of insulin, glucose, leptin, adiponectin, TNF-α, IL-1β, IL-6, NF-κB, as well as the expression of mir-155 and mir-21 in the visceral adipose tissue (VAT) of rats with T2DM.

METHODS

For this experimental study, 32 male Wistar rats were induced with T2DM by a high-fat diet combined with a low-dose streptozotocin injection. The rats were randomly assigned to four groups: AT and Mg supplementation (AT + Mg), AT (5 days/week for 8 weeks), Mg supplementation (received daily supplementation of Mg chloride), and diabetic control (C). An 8-week AT program was implemented, with gradually increasing the intensity and duration to reach 25 m/min and 60 min in the 8th week, respectively. The training intensity was set at 50-60% of VO2max. The Mg groups were provided with rat diets containing 1000 mg/kg of Mg. The AT + Mg group received both interventions, while the C group served as the untreated control. Serum biomarkers were measured using enzyme-linked immunosorbent assay (ELISA), and VAT samples were collected for gene expression analysis using real-time polymerase chain reaction (PCR).

RESULTS

Serum biomarker analysis revealed that the AT + Mg group had a significant decrease in fasting insulin (p = 0.001) and serum glucose (p = 0.001), as well as an increase in adiponectin levels compared to the C group (p = 0.002). Additionally, the AT + Mg group showed a significant reduction in serum leptin, TNF-α, IL-6, IL-1β, and NF-κB, as well as downregulation of mir-155 and mir-21 in the VAT compared to the other groups. The AT group also showed improvements in several parameters, while the Mg group had fewer significant differences compared to the C group.

CONCLUSION

The combination of AT and Mg supplementation provides a synergistic effect that improves serum biomarkers and downregulates pro-inflammatory microRNAs in the VAT of T2DM rats. Meanwhile, Mg supplementation alone does not have a significant effect on pro-inflammatory microRNAs in the VAT. These findings suggest that such combined interventions could be a promising strategy for managing T2DM, potentially ameliorating inflammatory states and improving metabolic health.

Dapagliflozin prevents kidney podocytes pyroptosis via miR-155-5p/HO-1/NLRP3 axis modulation

Diabetic nephropathy (DN) is a significant clinical microvascular complication associated with diabetes mellitus (DM), and end-stage diabetes giving rise to kidney failure is developing into the major etiological factor of chronic kidney failure. Dapagliflozin is reported to limit podocyte damage in DM, which has proven to protect against renal failure. Mounting evidence has demonstrated that pyroptosis is associated with DM progression. Nevertheless, whether pyroptosis causes DN and the underlying molecular pathways remain obscure. In this study, we aimed to explore the antipyroptotic attributes of dapagliflozin and elucidate the underlying mechanisms of kidney damage in diabetes. In vivo, experiments were conducted in streptozotocin (STZ)-induced type 2 diabetic mice, which were administered dapagliflozin via gavage for 6 weeks. Subsequently, the specific organizational characteristics and expression of pyroptosis-related genes were evaluated. Intragastric dapagliflozin administration markedly reduced renal tissue injury. Meanwhile, dapagliflozin also attenuated the expression level of pyroptosis associated genes, including ASC, cleaved Caspase-1, GSDMD N-termini, NLRP3, IL-18, and IL-1β in renal tissue of dapagliflozin-treated animals. Similar antipyroptotic effects were observed in palmitic acid (PA)-treated mouse podocytes. We also found that heme oxygenase 1 (HO-1) enhanced the protection of mouse podocyte clone 5 cells (MPC5). Moreover, miR-155-5p inhibition increased pyroptosis in PA-treated MPC5 cells, suggesting that miR-155-5p acts as an endogenous stimulator that increases HO-1 expression and reduces pyroptosis. Hence, our findings imply that dapagliflozin inhibits podocyte pyroptosis via the miR-155-5p/HO-1/NLRP3 axis in DM. Furthermore, dapagliflozin substitution may be regarded as an effective strategy for preventing pyroptosis in the kidney, including a therapeutic option for treating pyroptosis-related DN.

Islet-resident macrophage-derived miR-155 promotes β cell decompensation via targeting PDX1

Chronic inflammation is critical for the initiation and progression of type 2 diabetes mellitus via causing both insulin resistance and pancreatic β cell dysfunction. miR-155, highly expressed in macrophages, is a master regulator of chronic inflammation. Here we show that blocking a macrophage-derived exosomal miR-155 (MDE-miR-155) mitigates the insulin resistances and glucose intolerances in high-fat-diet (HFD) feeding and type-2 diabetic db/db mice. Lentivirus-based miR-155 sponge decreases the level of miR-155 in the pancreas and improves glucose-stimulated insulin secretion (GSIS) ability of β cells, thus leading to improvements of insulin sensitivities in the liver and adipose tissues. Mechanistically, miR-155 increases its expression in HFD and db/db islets and is released as exosomes by islet-resident macrophages under metabolic stressed conditions. MDE-miR-155 enters β cells and causes defects in GSIS function and insulin biosynthesis via the miR-155-PDX1 axis. Our findings offer a treatment strategy for inflammation-associated diabetes via targeting miR-155.

Genetic and Epigenetic Associations with Post-Transplant Diabetes Mellitus

Post-transplant diabetes mellitus (PTDM) is a common complication of solid organ transplantation. PTDM prevalence varies due to different diabetes definitions. Consensus guidelines for the diagnosis of PTDM have been published based on random blood glucose levels, glycated hemoglobin (HbA1c), and oral glucose tolerance test (OGTT). The task of diagnosing PTDM continues to pose challenges, given the potential for diabetes to manifest at different time points after transplantation, thus demanding constant clinical vigilance and repeated testing. Interpreting HbA1c levels can be challenging after renal transplantation. Pre-transplant risk factors for PTDM include obesity, sedentary lifestyle, family history of diabetes, ethnicity (e.g., African-Caribbean or South Asian ancestry), and genetic risk factors. Risk factors for PTDM include immunosuppressive drugs, weight gain, hepatitis C, and cytomegalovirus infection. There is also emerging evidence that genetic and epigenetic variation in the organ transplant recipient may influence the risk of developing PTDM. This review outlines many known risk factors for PTDM and details some of the pathways, genetic variants, and epigenetic features associated with PTDM. Improved understanding of established and emerging risk factors may help identify people at risk of developing PTDM and may reduce the risk of developing PTDM or improve the management of this complication of organ transplantation.

Progress in the treatment of diabetic cardiomyopathy, a systematic review

Diabetic cardiomyopathy (DCM) is a condition characterized by myocardial dysfunction that occurs in individuals with diabetes, in the absence of coronary artery disease, valve disease, and other conventional cardiovascular risk factors such as hypertension and dyslipidemia. It is considered a significant and consequential complication of diabetes in the field of cardiovascular medicine. The primary pathological manifestations include myocardial hypertrophy, myocardial fibrosis, and impaired ventricular function, which can lead to widespread myocardial necrosis. Ultimately, this can progress to the development of heart failure, arrhythmias, and cardiogenic shock, with severe cases even resulting in sudden cardiac death. Despite several decades of both fundamental and clinical research conducted globally, there are currently no specific targeted therapies available for DCM in clinical practice, and the incidence and mortality rates of heart failure remain persistently high. Thus, this article provides an overview of the current treatment modalities and novel techniques pertaining to DCM, aiming to offer valuable insights and support to researchers dedicated to investigating this complex condition.

The latest emerging drugs for the treatment of diabetic cardiomyopathy

INTRODUCTION

Diabetic cardiomyopathy (DCM) is a serious complication of diabetes mellitus involving multiple pathophysiologic mechanisms. In addition to hypoglycemic agents commonly used in diabetes, metabolism-related drugs, natural plant extracts, melatonin, exosomes, and rennin-angiotensin-aldosterone system are cardioprotective in DCM. However, there is a lack of systematic summarization of drugs for DCM.

AREAS COVERED

In this review, the authors systematically summarize the most recent drugs used for the treatment of DCM and discusses them from the perspective of DCM pathophysiological mechanisms.

EXPERT OPINION

We discuss DCM drugs from the perspective of the pathophysiological mechanisms of DCM, mainly including inflammation and metabolism. As a disease with multiple pathophysiological mechanisms, the combination of drugs may be more advantageous, and we have discussed some of the current studies on the combination of drugs.

Regulation of miRNA-155-5p ameliorates NETosis in pulmonary fibrosis rat model via inhibiting its target cytokines IL-1β, TNF-α and TGF-β1

Idiopathic pulmonary fibrosis (IPF) is an age-related inflammatory disease with no cure up till now.It is accompanied by neutrophils infiltration as the main responders to inflammation and fibrosis. Importantly, neutrophils release neutrophil extracellular traps (NETs) through NETosis process. The function of microRNAs during inflammation became of great biological attention. Owing to microRNAs' central role in immune system, microRNA-155-5p (miR-155-5p) is intensely involved in the inflammatory response. Capsaicin (Cap) is a bioactive compound that exhibits antioxidative and anti-inflammatory functions. Recent studies have shown its role in regulation of certain microRNAs' expressions. Accordingly, the present study aims to investigate the effect of miR-155-5p regulation in suppressing NETs production via ameliorating its target inflammatory cytokines, IL-1ß, TNF-α and TGF-ß1, in bleomycin (BLM)-induced pulmonary fibrosis rat model treated by Cap. The obtained results demonstrated that miR-155-5p downregulation was associated with significant decrease in IL-1ß, TNF-α, TGF-β1, which consequently, reduced hydroxyproline (HYP), NETs activity markers as NE and PAD-4, and alleviated CTGF levels in lung tissues of animals treated by Cap. Furthermore, NETosis ultrastructure examination by transmission electron microscope (TEM), MPO immunohistochemical staining and histopathological studies confirmed an abolishment in NETs formation and an improvement in lung tissue architecture in Cap-treated rats. This study concluded that Cap quenched the inflammatory response through interrupting IL-1β, TNF-α and TGF-β1 pathway via modulating miR-155-5p expression. In addition, Cap was able to alleviate pulmonary NETosis markers by restraining NETs activity markers. These findings provide novel insight into the application of Cap-based treatment in ameliorating pulmonary damage in IPF.

Identification of potential miR‑155 target genes in epidermal immune microenvironment of atopic dermatitis patients and their inflammatory effects on HaCaT cells

Atopic dermatitis (AD) is a common inflammatory skin condition and the leading cause of morbidity associated with skin conditions worldwide. For the majority of patients, AD is a lifelong disease that cannot be cured completely. Therefore, in the present study, differentially expressed genes (DEGs) in the epidermal immune microenvironment were screened using bioinformatic techniques. Subsequently, an in vitro cellular model was constructed to investigate the role of microRNA (miR)-155 in immune infiltration during AD. In the present study, two datasets (GSE121212 and GSE157194) were downloaded from Gene Expression Omnibus, before the DEGs were screened and subjected to Gene Ontology and Kyoto Encyclopedia of Genes and Genomes functional enrichment analyses. miRNet was used to predict the possible target genes of miR-155 among the differentially expressed genes found. Consequently, peptidase inhibitor 3 (PI3), FOS-like 1, AP-1 transcription factor subunit (FOSL1), C-X-C motif chemokine ligand (CXCL)1 and CXCL8 were selected to be the potential target genes of miR-155 in the epidermal immune microenvironment of patients with AD. Concurrently, an inflammatory cell model using HaCaT cells was constructed by TNF-α and IFN-γ treatment. The effects of miR-155 on HaCaT cell proliferation and secretion of IL-1β, IL-6, IL-10, IL-15, PI3, FOSL1, CXCL1 and CXCL8 under inflammatory and non-inflammatory conditions were then analyzed. The results showed that after the HaCaT cells were transfected with miR-155, miR-155 inhibited HaCaT cell proliferation and decreased the mRNA expression levels of PI3 and CXCL8, increased the mRNA levels of FOSL1 and secretion levels of IL-1β, IL-6, IL-15 and CXCL1. By contrast, miR-155 decreased the secretion levels of IL-10 and CXCL8. In the inflammatory cell model of HaCaT cells, miR-155 was found to significantly inhibit the proliferation of HaCaT cells during inflammation whilst significantly increasing the secretion of IL-1β, IL-6, IL-10 and IL-15. In addition, miR-155 increased the mRNA expression and secretion levels of CXCL1 and CXCL8, whilst also increasing the mRNA expression levels of PI3. Results from the current study suggest that miR-155 can stimulate keratinocytes to produce inflammatory cytokines and proteins to enhance the inflammatory response in AD.

Treatment of type 2 diabetes mellitus with stem cells and antidiabetic drugs: a dualistic and future-focused approach

Type 2 Diabetes Mellitus (T2DM) accounts for more than 90% of total diabetes mellitus cases all over the world. Obesity and lack of balance between energy intake and energy expenditure are closely linked to T2DM. Initial pharmaceutical treatment and lifestyle interventions can at times lead to remission but usually help alleviate it to a certain extent and the condition remains, thus, recurrent with the patient being permanently pharmaco-dependent. Mesenchymal stromal cells (MSCs) are multipotent, self-renewing cells with the ability to secrete a variety of biological factors that can help restore and repair injured tissues. MSC-derived exosomes possess these properties of the original stem cells and are potentially able to confer superior effects due to advanced cell-to-cell signaling and the presence of stem cell-specific miRNAs. On the other hand, the repository of antidiabetic agents is constantly updated with novel T2DM disease-modifying drugs, with higher efficacy and increasingly convenient delivery protocols. Delving deeply, this review details the latest progress and ongoing studies related to the amalgamation of stem cells and antidiabetic drugs, establishing how this harmonized approach can exert superior effects in the management and potential reversal of T2DM.

A mutual regulatory loop between miR-155 and SOCS1 influences renal inflammation and diabetic kidney disease

Diabetic kidney disease (DKD) is a common microvascular complication of diabetes, a global health issue. Hyperglycemia, in concert with cytokines, activates the Janus kinase (JAK)/signal transducer and activator of transcription (STAT) pathway to induce inflammation and oxidative stress contributing to renal damage. There is evidence of microRNA-155 (miR-155) involvement in diabetes complications, but the underlying mechanisms are unclear. In this study, gain- and loss-of-function experiments were conducted to investigate the interplay between miR-155-5p and suppressor of cytokine signaling 1 (SOCS1) in the regulation of the JAK/STAT pathway during renal inflammation and DKD. In experimental models of mesangial injury and diabetes, miR-155-5p expression correlated inversely with SOCS1 and positively with albuminuria and expression levels of cytokines and prooxidant genes. In renal cells, miR-155-5p mimic downregulated SOCS1 and promoted STAT1/3 activation, cytokine expression, and cell proliferation and migration. Conversely, both miR-155-5p antagonism and SOCS1 overexpression protected cells from inflammation and hyperglycemia damage. In vivo, SOCS1 gene delivery decreased miR-155-5p and kidney injury in diabetic mice. Moreover, therapeutic inhibition of miR-155-5p suppressed STAT1/3 activation and alleviated albuminuria, mesangial damage, and renal expression of inflammatory and fibrotic genes. In conclusion, modulation of the miR-155/SOCS1 axis protects kidneys against diabetic damage, thus highlighting its potential as therapeutic target for DKD.

MicroRNA193a: An Emerging Mediator of Glomerular Diseases

MicroRNAs (miRNAs) are noncoding small RNAs that regulate the protein expression of coding messenger RNAs. They are used as biomarkers to aid in diagnosing, prognosticating, and surveillance of diseases, especially solid cancers. MiR-193a was shown to be directly pathogenic in an experimental mouse model of focal segmental glomerulosclerosis (FSGS) during the last decade. Its specific binding and downregulation of Wilm's tumor-1 (WT-1), a transcription factor regulating podocyte phenotype, is documented. Also, miR-193a is a regulator switch causing the transdifferentiation of glomerular parietal epithelial cells to a podocyte phenotype in in vitro study. Interaction between miR-193a and apolipoprotein 1 (APOL1) mRNA in glomeruli (filtration units of kidneys) is potentially involved in the pathogenesis of common glomerular diseases. Since the last decade, there has been an increasing interest in the role of miR-193a in glomerular diseases, including diabetic nephropathy and membranous nephropathy, besides FSGS. Considering the lack of biomarkers to manage FSGS and diabetic nephropathy clinically, it is worthwhile to invest in evaluating miR-193a in the pathogenesis of these diseases. What causes the upregulation of miR-193a in FSGS and how the mechanism is different in different glomerular disorders still need to be elucidated. This narrative review highlights the pathogenic mechanisms of miR-193a elevation in various glomerular diseases and its potential use in clinical management.

Network analysis identifies circulating miR-155 as predictive biomarker of type 2 diabetes mellitus development in obese patients: a pilot study

Obesity is the main risk factor for many non-communicable diseases. In clinical practice, unspecific markers are used for the determination of metabolic alterations and inflammation, without allowing the characterization of subjects at higher risk of complications. Circulating microRNAs represent an attractive approach for early screening to identify subjects affected by obesity more at risk of developing connected pathologies. The aim of this study was the identification of circulating free and extracellular vesicles (EVs)-embedded microRNAs able to identify obese patients at higher risk of type 2 diabetes (DM2). The expression data of circulating microRNAs derived from obese patients (OB), with DM2 (OBDM) and healthy donors were combined with clinical data, through network-based methodology implemented by weighted gene co-expression network analysis. The six circulating microRNAs overexpressed in OBDM patients were evaluated in a second group of patients, confirming the overexpression of miR-155-5p in OBDM patients. Interestingly, the combination of miR-155-5p with serum levels of IL-8, Leptin and RAGE was useful to identify OB patients most at risk of developing DM2. These results suggest that miR-155-5p is a potential circulating biomarker for DM2 and that the combination of this microRNA with other inflammatory markers in OB patients can predict the risk of developing DM2.

MicroRNAs and Nonalcoholic Steatohepatitis: A Review

Non-alcoholic fatty liver disease (NAFLD) is a clinicopathologic syndrome caused by fat deposition in hepatocytes. Patients with nonalcoholic steatohepatitis (NASH), an advanced form of NAFLD with severe fibrosis, are at high risk for liver-related complications, including hepatocellular carcinoma (HCC). However, the mechanism of progression from simple fat deposition to NASH is complex, and previous reports have linked NAFLD to gut microbiota, bile acids, immunity, adipokines, oxidative stress, and genetic or epigenetic factors. NASH-related liver injury involves multiple cell types, and intercellular signaling is thought to be mediated by extracellular vesicles. MicroRNAs (miRNAs) are short, noncoding RNAs that play important roles as post-transcriptional regulators of gene expression and have been implicated in the pathogenesis of various diseases. Recently, many reports have implicated microRNAs in the pathogenesis of NALFD/NASH, suggesting that exosomal miRNAs are potential non-invasive and sensitive biomarkers and that the microRNAs involved in the mechanism of the progression of NASH may be potential therapeutic target molecules. We are interested in which miRNAs are involved in the pathogenesis of NASH and which are potential target molecules for therapy. We summarize targeted miRNAs associated with the etiology and progression of NASH and discuss each miRNA in terms of its pathophysiology, potential therapeutic applications, and efficacy as a NASH biomarker.

MicroRNA-155 mediates endogenous angiotensin II type 1 receptor regulation: implications for innovative type 2 diabetes mellitus management

Type 2 diabetes mellitus (T2DM) is a lifelong condition and a threat to human health. Thorough understanding of its pathogenesis is acutely needed in order to devise innovative, preventative, and potentially curative pharmacological interventions. MicroRNAs (miRNA), are small, non-coding, one-stranded RNA molecules, that can target and silence around 60% of all human genes through translational repression. MiR-155 is an ancient, evolutionarily well-conserved miRNA, with distinct expression profiles and multifunctionality, and a target repertoire of over 241 genes involved in numerous physiological and pathological processes including hematopoietic lineage differentiation, immunity, inflammation, viral infections, cancer, cardiovascular conditions, and particularly diabetes mellitus. MiR-155 Levels are progressively reduced in aging, obesity, sarcopenia, and T2DM. Thus, the loss of coordinated repression of multiple miR-155 targets acting as negative regulators, such as C/EBPβ, HDAC4, and SOCS1 impacts insulin signaling, deteriorating glucose homeostasis, and causing insulin resistance (IR). Moreover, deranged regulation of the renin angiotensin aldo-sterone system (RAAS) through loss of Angiotensin II Type 1 receptor downregulation, and negated repression of ETS-1, results in unopposed detrimental Angiotensin II effects, further promoting IR. Finally, loss of BACH1 and SOCS1 repression abolishes cytoprotective, anti-oxidant, anti-apoptotic, and anti-inflammatory cellular pathways, and promotes β-cell loss. In contrast to RAAS inhibitor treatments that further decrease already reduced miR-155 Levels, strategies to increase an ailing miR-155 production in T2DM, e.g., the use of metformin, mineralocorticoid receptor blockers (spironolactone, eplerenone, finerenone), and verapamil, alone or in various combinations, represent current treatment options. In the future, direct tissue delivery of miRNA analogs is likely.

Low‑dose ionizing radiation attenuates high glucose‑induced hepatic apoptosis and immune factor release via modulation of a miR‑155‑SOCS1 axis

Diabetic liver injury (DLI) can result in several diseases of the liver, including steatohepatitis, liver fibrosis, cirrhosis, and liver cancer. Low‑dose ionizing radiation (LDIR) has hormetic effects in normal/disease conditions. However, whether LDIR has a beneficial effect on DLI has not been assessed previously. MicroRNA (miR)‑155 and its target gene suppressor of cytokine signaling 1 (SOCS1) play critical roles in modulating hepatic proliferation, apoptosis, and immunity. However, whether a miR‑155‑SOCS1 axis is involved in high glucose (HG) induced hepatic damage remains to be determined. In the present study, mouse hepatocyte AML12 cells were treated with 30 mM glucose (HG), 75 mGy X‑ray (LDIR), or HG plus LDIR. The expression levels of miR‑155 and SOCS1 were determined by reverse transcription‑quantitative PCR and western blotting. Additionally, apoptosis was measured using flow cytometry. The release of inflammatory factors, including TNF‑α, IL‑1β, IL‑6, IL‑10, and IFN‑γ, after HG and/or LDIR treatment was detected by ELISA. The results showed that HG may induce hepatic apoptosis by upregulating the levels of miR‑155 and downregulating the levels of SOCS1. HG also stimulated the secretion of TNF‑α, IL‑1β, IL‑6, and IL‑10. However, LDIR blocked the HG‑induced activation of a miR‑155‑SOCS1 axis and suppressed the release of inflammatory factors. These results indicated that a miR‑155‑SOCS1 axis plays a role in HG‑induced liver injury, and LDIR may exert a hepatoprotective effect by regulating the miR‑155‑SOCS1 axis.

Long-Term LDL-Apheresis Treatment and Dynamics of Circulating miRNAs in Patients with Severe Familial Hypercholesterolemia

Lipoprotein apheresis (LA) is a therapeutic option for patients with severe hypercholesterolemia who have persistently elevated LDL-C levels despite attempts at drug therapy. MicroRNAs (miRNAs), important posttranscriptional gene regulators, are involved in the pathogenesis of atherosclerosis. Our study aimed to monitor the dynamics of twenty preselected circulating miRNAs in patients under long-term apheresis treatment. Plasma samples from 12 FH patients (men = 50%, age = 55.3 ± 12.2 years; mean LA overall treatment time = 13.1 ± 7.8 years) were collected before each apheresis therapy every sixth month over the course of four years of treatment. Eight complete follow-up (FU) samples were measured in each patient. Dynamic changes in the relative quantity of 6 miRNAs (miR-92a, miR-21, miR-126, miR-122, miR-26a, and miR-185; all p < 0.04) during FU were identified. Overall apheresis treatment time influenced circulating miR-146a levels (p < 0.04). In LDLR mutation homozygotes (N = 5), compared to heterozygotes (N = 7), we found higher plasma levels of miR-181, miR-126, miR-155, and miR-92a (all p < 0.03). Treatment with PCSK9 inhibitors (N = 6) affected the plasma levels of 7 miRNAs (miR-126, miR-122, miR-26a, miR-155, miR-125a, miR-92a, and miR-27a; all p < 0.04). Long-term monitoring has shown that LA in patients with severe familial hypercholesterolemia influences plasma circulating miRNAs involved in endothelial dysfunction, cholesterol homeostasis, inflammation, and plaque development. The longer the treatment using LA, the better the miRNA milieu depicting the potential cardiovascular risk.

The role of microRNAs in pathophysiology and diagnostics of metabolic complications in obstructive sleep apnea patients

Obstructive sleep apnea (OSA) is one of the most common sleep disorders, which is characterized by recurrent apneas and/or hypopneas occurring during sleep due to upper airway obstruction. Among a variety of health consequences, OSA patients are particularly susceptible to developing metabolic complications, such as metabolic syndrome and diabetes mellitus type 2. MicroRNAs (miRNAs) as epigenetic modulators are promising particles in both understanding the pathophysiology of OSA and the prediction of OSA complications. This review describes the role of miRNAs in the development of OSA-associated metabolic complications. Moreover, it summarizes the usefulness of miRNAs as biomarkers in predicting the aforementioned OSA complications.

The Link between Diabetes, Pancreatic Tumors, and miRNAs-New Players for Diagnosis and Therapy?

Despite significant progress in medicine, pancreatic cancer is one of the most tardily diagnosed cancer and is consequently associated with a poor prognosis and a low survival rate. The asymptomatic clinical picture and the lack of relevant diagnostic markers for the early stages of pancreatic cancer are believed to be the major constraints behind an accurate diagnosis of this disease. Furthermore, underlying mechanisms of pancreatic cancer development are still poorly recognized. It is well accepted that diabetes increases the risk of pancreatic cancer development, however the precise mechanisms are weakly investigated. Recent studies are focused on microRNAs as a causative factor of pancreatic cancer. This review aims to provide an overview of the current knowledge of pancreatic cancer and diabetes-associated microRNAs, and their potential in diagnosis and therapy. miR-96, miR-124, miR-21, and miR-10a were identified as promising biomarkers for early pancreatic cancer prediction. miR-26a, miR-101, and miR-200b carry therapeutic potential, as they not only regulate significant biological pathways, including the TGF-β and PI3K/AKT, but their re-expression contributes to the improvement of the prognosis by reducing invasiveness or chemoresistance. In diabetes, there are also changes in the expression of microRNAs, such as in miR-145, miR-29c, and miR-143. These microRNAs are involved, among others, in insulin signaling, including IRS-1 and AKT (miR-145), glucose homeostasis (hsa-miR-21), and glucose reuptake and gluconeogenesis (miR-29c). Although, changes in the expression of the same microRNAs are observed in both pancreatic cancer and diabetes, they exert different molecular effects. For example, miR-181a is upregulated in both pancreatic cancer and diabetes mellitus, but in diabetes it contributes to insulin resistance, whereas in pancreatic cancer it promotes tumor cell migration, respectively. To conclude, dysregulated microRNAs in diabetes affect crucial cellular processes that are involved in pancreatic cancer development and progression.

The role of miR-155 on liver diseases by modulating immunity, inflammation and tumorigenesis

The liver is a well-known metabolic organ that can be susceptible to external stimuli to affect its normal physiological function. Worldwide, the morbidity and mortality of liver diseases are skyrocketing every year, causing human health crises. Recently, new approaches such as biotechnology have been introduced to achieve optimal treatment and prognostic management of liver diseases. microRNAs (miRNAs), a kind of small non-coding RNA molecule, have the advantages of biodiversity, wide distribution and numerous members. Among these miRNAs, miR-155 is an important regulator of inflammation, immunity and tumorigenesis. In this review, the PubMed and Web of Science databases were searched from 2009 to 2022. After inclusion and exclusion, 64 articles were selected for a systematic review to comprehensively summarize the mechanisms of miR-155 regulating inflammation, immunity and tumorigenesis in liver diseases and liver cancer, covering in vitro, in vivo and clinical studies. Existing preclinical studies and clinical trials have listed that the up-regulation and down-regulation of miR-155 are significant in alcoholic liver injury, viral hepatitis, autoimmune hepatitis, infectious liver injury, liver transplantation and liver cancer. The immune and inflammation effects of miR-155 are manifested by regulating macrophage polarization, NK cell killing, Th17 cell and Th1/Th2 cell differentiation. Additionally, miR-155 is also committed to participating in the cell cycle, invasion and metastasis, immune escape and other processes to promote and intensify the development of liver cancer. In conclusion, miR-155 is not only a biomarker for the diagnosis and prognosis of liver diseases, but also plays a therapeutic role via regulating immunity, inflammation and tumorigenesis.

The role of miRNAs in insulin resistance and diabetic macrovascular complications - A review

Diabetes is the most prevalent metabolic disturbance disease and has been regarded globally as one of the principal causes of mortality. Diabetes is accompanied by several macrovascular complications, including stroke, coronary artery disease (CAD), and cardiomyopathy as a consequence of atherosclerosis. The onset of type 2 diabetes is closely related to insulin resistance (IR). miRNAs have been linked to various metabolic processes, including glucose homeostasis, regulation of lipid metabolism, gluconeogenesis, adipogenesis, glucose transporter type 4 expression, insulin sensitivity, and signaling. Consequently, miRNA dysregulation mediates IR in some target organs, comprising liver, muscle, and adipose tissue. Moreover, miRNAs are crucial in developing diabetes and its associated macrovascular complications through their roles in several signaling pathways implicated in inflammation, apoptosis, cellular survival and migration, the proliferation of vascular smooth muscle cells, neurogenesis, angiogenesis, autophagy, oxidative stress, cardiac remodeling, and fibrosis. Therefore, the purpose of this review is to clarify the role of miRNAs in hepatic, muscle, and adipose tissue IR and explain their roles in the pathogenesis of macrovascular diabetic complications, including stroke, CAD, and cardiomyopathy. Also, explain their roles in gestational diabetes mellitus (GDM). Besides, this review discusses the latest updates on the alteration of miRNA expression in diabetic macrovascular complications.

Human pancreatic islet microRNAs implicated in diabetes and related traits by large-scale genetic analysis

Genetic studies have identified ≥240 loci associated with the risk of type 2 diabetes (T2D), yet most of these loci lie in non-coding regions, masking the underlying molecular mechanisms. Recent studies investigating mRNA expression in human pancreatic islets have yielded important insights into the molecular drivers of normal islet function and T2D pathophysiology. However, similar studies investigating microRNA (miRNA) expression remain limited. Here, we present data from 63 individuals, the largest sequencing-based analysis of miRNA expression in human islets to date. We characterized the genetic regulation of miRNA expression by decomposing the expression of highly heritable miRNAs into cis- and trans-acting genetic components and mapping cis-acting loci associated with miRNA expression [miRNA-expression quantitative trait loci (eQTLs)]. We found i) 84 heritable miRNAs, primarily regulated by trans-acting genetic effects, and ii) 5 miRNA-eQTLs. We also used several different strategies to identify T2D-associated miRNAs. First, we colocalized miRNA-eQTLs with genetic loci associated with T2D and multiple glycemic traits, identifying one miRNA, miR-1908, that shares genetic signals for blood glucose and glycated hemoglobin (HbA1c). Next, we intersected miRNA seed regions and predicted target sites with credible set SNPs associated with T2D and glycemic traits and found 32 miRNAs that may have altered binding and function due to disrupted seed regions. Finally, we performed differential expression analysis and identified 14 miRNAs associated with T2D status-including miR-187-3p, miR-21-5p, miR-668, and miR-199b-5p-and 4 miRNAs associated with a polygenic score for HbA1c levels-miR-216a, miR-25, miR-30a-3p, and miR-30a-5p.

Mitochondrial microRNAs Are Dysregulated in Patients with Fabry Disease

Fabry disease (FD) is a lysosomal storage disorder caused by mutations in the gene for α-galactosidase A, inducing a progressive accumulation of globotriaosylceramide (GB3) and its metabolites in different organs and tissues. GB3 deposition does not fully explain the clinical manifestations of FD, and other pathogenetic mechanisms have been proposed, requiring the identification of new biomarkers for monitoring FD patients. Emerging evidence suggests the involvement of mitochondrial alterations in FD. Here, we propose mitochondrial-related microRNAs (miRs) as potential biomarkers of mitochondrial involvement in FD. Indeed, we demonstate that miRs regulating different aspects of mitochondrial homeostasis including expression and assembly of respiratory chain, mitogenesis, antioxidant capacity, and apoptosis are consistently dysregulated in FD patients. Our data unveil a novel noncoding RNA signature of FD patients, indicating mitochondrial-related miRs as new potential pathogenic players and biomarkers in FD. SIGNIFICANCE STATEMENT: This study demonstrates for the first time that a specific signature of circulating mitochondrial miRs (mitomiRs) is dysregulated in FD patients. MitomiRs regulating fundamental aspects of mitochondrial homeostasis and fitness, including expression and assembly of the respiratory chain, mitogenesis, antioxidant capacity, and apoptosis are significantly dysregulated in FD patients. Taken together, these new findings introduce mitomiRs as unprecedented biomarkers of FD and point at mitochondrial dysfunction as a novel potential mechanistic target for therapeutic approaches.

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

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

Clinical Application of Serum microRNAs in Atherosclerotic Coronary Artery Disease

MicroRNAs (miRs) are promising diagnostic, prognostic and therapeutic biomolecules for atherosclerotic cardiovascular disease. Atherosclerotic occlusive disease concerns a large population of patients, carrying the highest incidence of fatal and non-fatal adverse events, such as myocardial infarction, ischemic stroke, and limb ischemia, worldwide. Consistently, miRs are involved in regulation and pathogenesis of atherosclerotic coronary artery disease (CAD), acute coronary syndromes (ACS), both with ST-segment (STEMI) and non-ST segment elevation myocardial infarctions (NSTEMI), as well as cardiac remodeling and fibrosis following ACS. However, the genetic and molecular mechanisms underlying adverse outcomes in CAD are multifactorial, and sometimes difficult to interpret for clinicians. Therefore, in the present review paper we have focused on the clinical meaning and the interpretation of various miRs findings, and their potential application in routine clinical practice.

Identification of the shared gene signatures and pathways between sarcopenia and type 2 diabetes mellitus

Background

Sarcopenia is characterized by the age-associated loss of skeletal muscle mass and strength that develops progressively and plays an important role in the disability of the elderly. It has received growing attention over the last decade and has been implicated as both a cause and consequence of type 2 diabetes mellitus (T2DM). The existence of T2DM could increase the risk of developing sarcopenia through multiple mechanisms including advanced glycation end-product accumulation. Meanwhile, sarcopenia would alter glucose disposal and may contribute to the development and progression of T2DM due to reduced muscle mass.

Methods

We implemented transcriptomic analysis of skeletal muscle biopsy specimens in sarcopenia patients and proliferating myoblasts or differentiated myotubes from individuals with T2DM. Related microarray data were selected from Gene Expression Omnibus (GEO) to screen the genes, which were differentially expressed for sarcopenia and T2DM. Multiple combinatorial statistical methods and bioinformatics tools were used to analyze the common DEGs. Meanwhile, functional enrichment analysis was also carried out. Furthermore, we constructed the protein-protein interaction (PPI), as well as transcription factor (TF)-gene interactions network and TF-miRNA coregulatory network. Finally, based on the common DEGs, drug compounds were speculated using the Drug Signatures database (DSigDB).

Results

A total of 1765 and 2155 DEGs of sarcopenia and T2DM were screened, respectively. 15 common genes (LXN, CIB2, PEA15, KANK2, FGD1, NMRK1, PLCB1, SEMA4G, ADARB1, UPF3A, CSTB, COL3A1, CD99, ETV3, FJX1) correlated with sarcopenia and T2DM simultaneously were then identified, and 3 genes (UPF3A, CSTB and PEA15) of them were regarded as hub genes. Functional enrichment analysis revealed several shared pathways between two diseases. In addition, according to the TF-gene interactions network and TF-miRNA coregulatory network, part of TF and miRNA may be identified as key regulator in sarcopenia and T2DM at the same time (e.g., CREM and miR-155). Notably, drug compounds for T2DM and sarcopenia were also suggested, such as coenzyme Q10.

Conclusion

This study revealed that sarcopenia and T2DM may share similar pathogenesis and provided new biological targets and ideas for early diagnosis and effective treatment of sarcopenia and T2DM.

Pathogenesis of Type 1 Diabetes: Established Facts and New Insights

Type 1 diabetes (T1D) is an autoimmune disease characterized by the T-cell-mediated destruction of insulin-producing β-cells in pancreatic islets. It generally occurs in genetically susceptible individuals, and genetics plays a major role in the development of islet autoimmunity. Furthermore, these processes are heterogeneous among individuals; hence, different endotypes have been proposed. In this review, we highlight the interplay between genetic predisposition and other non-genetic factors, such as viral infections, diet, and gut biome, which all potentially contribute to the aetiology of T1D. We also discuss a possible active role for β-cells in initiating the pathological processes. Another component in T1D predisposition is epigenetic influences, which represent a link between genetic susceptibility and environmental factors and may account for some of the disease heterogeneity. Accordingly, a shift towards personalized therapies may improve the treatment results and, therefore, result in better outcomes for individuals in the long-run. There is also a clear need for a better understanding of the preclinical phases of T1D and finding new predictive biomarkers for earlier diagnosis and therapy, with the final goal of reverting or even preventing the development of the disease.

Cardiac Remodeling After Myocardial Infarction: Functional Contribution of microRNAs to Inflammation and Fibrosis

After an ischemic injury, the heart undergoes a complex process of structural and functional remodeling that involves several steps, including inflammatory and fibrotic responses. In this review, we are focusing on the contribution of microRNAs in the regulation of inflammation and fibrosis after myocardial infarction. We summarize the most updated studies exploring the interactions between microRNAs and key regulators of inflammation and fibroblast activation and we discuss the recent discoveries, including clinical applications, in these rapidly advancing fields.

Kidney microRNA Expression Pattern in Type 2 Diabetic Nephropathy in BTBR Ob/Ob Mice

Diabetic nephropathy (DN) is the main leading cause of chronic kidney disease worldwide. Although remarkable therapeutic advances have been made during the last few years, there still exists a high residual risk of disease progression to end-stage renal failure. To further understand the pathogenesis of tissue injury in this disease, by means of the Next-Generation Sequencing, we have studied the microRNA (miRNA) differential expression pattern in kidneys of Black and Tan Brachyury (BTBR) ob/ob (leptin deficiency mutation) mouse. This experimental model of type 2 diabetes and obesity recapitulates the key histopathological features described in advanced human DN and therefore can provide potential useful translational information. The miRNA-seq analysis, performed in the renal cortex of 22-week-old BTBR ob/ob mice, pointed out a set of 99 miRNAs significantly increased compared to non-diabetic, non-obese control mice of the same age, whereas no miRNAs were significantly decreased. Among them, miR-802, miR-34a, miR-132, miR-101a, and mir-379 were the most upregulated ones in diabetic kidneys. The in silico prediction of potential targets for the 99 miRNAs highlighted inflammatory and immune processes, as the most relevant pathways, emphasizing the importance of inflammation in the pathogenesis of kidney damage associated to diabetes. Other identified top canonical pathways were adipogenesis (related with ectopic fatty accumulation), necroptosis (an inflammatory and regulated form of cell death), and epithelial-to-mesenchymal transition, the latter supporting the importance of tubular cell phenotype changes in the pathogenesis of DN. These findings could facilitate a better understanding of this complex disease and potentially open new avenues for the design of novel therapeutic approaches to DN.

Functional Role of microRNAs in Regulating Cardiomyocyte Death

microRNAs (miRNA, miRs) play crucial roles in cardiovascular disease regulating numerous processes, including inflammation, cell proliferation, angiogenesis, and cell death. Herein, we present an updated and comprehensive overview of the functional involvement of miRs in the regulation of cardiomyocyte death, a central event in acute myocardial infarction, ischemia/reperfusion, and heart failure. Specifically, in this systematic review we are focusing on necrosis, apoptosis, and autophagy.

Micro-RNA Implications in Type-1 Diabetes Mellitus: A Review of Literature

Type-1 diabetes mellitus (T1DM) is one of the most well-defined and complex metabolic disorders, characterized by hyperglycemia, with a constantly increasing incidence in children and adolescents. While current knowledge regarding the molecules related to the pathogenesis and diagnosis of T1DM is vast, the discovery of new molecules, such as micro ribonucleic acids (micro-RNAs, miRNAs), as well as their interactions with T1DM, has spurred novel prospects in the diagnosis of the disease. This review aims at summarizing current knowledge regarding miRNAs' biosynthesis and action pathways and their role as gene expression regulators in T1DM. MiRNAs follow a complex biosynthesis pathway, including cleaving and transport from nucleus to cytoplasm. After assembly of their final form, they inhibit translation or cause messenger RNA (mRNA) degradation, resulting in the obstruction of protein synthesis. Many studies have reported miRNA involvement in T1DM pathogenesis, mainly through interference with pancreatic b-cell function, insulin production and secretion. They are also found to contribute to β-cell destruction, as they aid in the production of autoreactive agents. Due to their elevated accumulation in various biological specimens, as well as their involvement in T1DM pathogenesis, their role as biomarkers in early preclinical T1DM diagnosis is widely hypothesized, with future studies concerning their diagnostic value deemed a necessity.

Expression of miR-1-3p, miR-16-5p and miR-122-5p as Possible Risk Factors of Secondary Cardiovascular Events

Ischemic event in one arterial territory increases the risk of a subsequent ischemic event. Circulating microRNAs (miRs) emerge as a potential clinical tool to assess risk of subsequent atherothrombotic events such as cardiovascular death (CVD), myocardial infarction (MI) and ischemic stroke (IS). In this prospective study, we searched for athero-specific miRs related to cardiovascular event risk in patients with symptomatic coronary, carotid lesion, or both territories involvements. The choice of particular miRs was based on database research (Pub-Med, Bethesda, MD, USA) taking into consideration the relationship with development of atherosclerosis and potential prognostic value. Levels of circulating miRs (miR-1-3p, miR-16-5p, miR-34a-5p, mir-122-5p, miR-124-3p, miR-133a-3p, miR-133b, miR-134-5p, miR-208b-3p, miR-375 and miR-499-5p) were compared in 142 patients with an acute ischemic event resulting from carotid and/or coronary artery stenosis, who underwent revascularization for symptomatic lesion. A 6-year prospective evaluation of CVD/MI/IS risk was performed. Patients with two-territory as compared to single-territory involvement differed in levels of miR-1-3p (p = 0.016), miR-16-5p (p < 0.001), miR-34a-5p (p = 0.018), miR-122-5p (p = 0.007), miR-124-3p (p < 0.001) and miR-499-5p (p < 0.001). During follow-up, 62 (43.7%) episodes of CVD/MI/IS occurred. In multivariate Cox analysis, miR-122-5p (HR = 1.0006, 95%CI = 1.0001–1.0011) and peripheral artery disease (PAD) (HR = 2.16, 95%CI = 1.26–3.70) were associated with CVD/MI/IS risk; miR-1-3p (HR = 2.73, 95%CI = 1.22–6.12) and PAD (HR = 3.47, 95%CI = 1.88–6.41) with CVD; miR-122-5p (HR = 1.0001, 95%CI = 1.000–1.0002) and creatinine level (HR = 1.02, 95%CI = 1.01–1.04) with IS, and miR-16-5p (HR = 1.0004, 95%CI = 1.0001–1.0008) with MI. Expression of miR-1-3p, miR-16-5p and miR-122-5p during incident ischemia may be possible risk factors of secondary cardiovascular event(s).

Cognitive Impairment in Frail Hypertensive Elderly Patients: Role of Hyperglycemia

Endothelial dysfunction is a key hallmark of hypertension, which is a leading risk factor for cognitive decline in older adults with or without frailty. Similarly, hyperglycemia is known to impair endothelial function and is a predictor of severe cardiovascular outcomes, independent of the presence of diabetes. On these grounds, we designed a study to assess the effects of high-glucose and metformin on brain microvascular endothelial cells (ECs) and on cognitive impairment in frail hypertensive patients. We tested the effects of metformin on high-glucose-induced cell death, cell permeability, and generation of reactive oxygen species in vitro, in human brain microvascular ECs. To investigate the consequences of hyperglycemia and metformin in the clinical scenario, we recruited frail hypertensive patients and we evaluated their Montreal Cognitive Assessment (MoCA) scores, comparing them according to the glycemic status (normoglycemic vs. hyperglycemic) and the use of metformin. We enrolled 376 patients, of which 209 successfully completed the study. We observed a significant correlation between MoCA score and glycemia. We found that hyperglycemic patients treated with metformin had a significantly better MoCA score than hyperglycemic patients treated with insulin (18.32 ± 3.9 vs. 14.94 ± 3.8; p < 0.001). Our in vitro assays confirmed the beneficial effects of metformin on human brain microvascular ECs. To our knowledge, this is the first study correlating MoCA score and glycemia in frail and hypertensive older adults, showing that hyperglycemia aggravates cognitive impairment.