Therapeutic Potential of miRNAs for Type 2 Diabetes Mellitus: An Overview

Altered microRNA Expression Correlates with Reduced TLR2/4-Dependent Periodontal Inflammation and Bone Resorption Induced by Polymicrobial Infection

Periodontitis (PD) is a polymicrobial dysbiotic immuno-inflammatory disease. Toll-like receptors (TLRs) are present on gingival epithelial cells and recognize pathogen-associated molecular patterns (PAMPs) on pathogenic bacteria, induce the secretion of proinflammatory cytokines, and initiate innate and adaptive antigen-specific immune responses to eradicate the invading microbes. Since PD is a chronic inflammatory disease, TLR2/TLR4 plays a vital role in disease pathogenesis and maintaining the periodontium during health. Many factors modulate the TLR-mediated signaling pathway, including specific miRNAs. The present study was designed to characterize the function of TLR2/4 signaling to the miRNA profile after polybacterial infection with Streptococcus gordonii, Fusobacterium nucleatum, Porphyromonas gingivalis, Treponema denticola, and Tannerella forsythia in C57BL6/J wild-type, TLR2 -/- , and TLR4 -/- mice (n=16/group) using RT-qPCR. The selection of 15 dominant miRNAs for RT-qPCR analysis was based on prior NanoString global miRNA expression profiling in response to polymicrobial and monobacterial infection. Polybacterial infections established gingival colonization in wild-type, TLR2 -/- and TLR4 -/- mice with induction of bacterial-specific IgG. A significant reduction in alveolar bone resorption (ABR) and gingival inflammation was observed in the mandibles of TLR2/4 -/- mice compared to C57BL6/J wild-type mice ( p <0.0001). Periodontal bacteria disseminated from gingival tissue to the multiple organs in wild-type and TLR2 -/- mice (heart, lungs, brain, kidney) and limited to heart ( F. nucleatum ), lungs ( P. gingivalis ), kidney ( T. forsythia ) in TLR4 -/- mice. The diagnostic potential of miRNAs was assessed by receiver operating characteristic (ROC) curves. Among 15 miRNAs, three were upregulated in C57BL6/J wild-type mice, two in TLR2 -/- , and seven in TLR4 -/- mice. Notably, the anti-inflammatory miR-146a-5p was consistently upregulated in all the mice. Additionally, miR-15a-5p was upregulated in wild-type and TLR2 -/- mice. let-7c-5p was upregulated in TLR4 -/- mice and downregulated in the wild-type mice. Multi-species oral bacterial infection alters the TLR2/4 signaling pathways by modulating the expression of several potential biomarker miRNAs in periodontium.

IMPORTANCE

Periodontitis is the most prevalent chronic immuno-infectious multispecies dysbiotic disease of the oral cavity. The Toll-like receptors (TLR) provide the first line of defense, one of the best-characterized pathogens-detection systems and play a vital role in recognizing multiple microbial products. Multispecies infection with periodontal bacteria S. gordonii, F. nucleatum, P. gingivalis, T. denticola, and T. forsythia induced gingival inflammation, alveolar bone resorption (ABR) and miRNA expression in the C57BL6/J wild-type mice and whereas infection did not increase significant ABR in the TLR2/4 deficient mice. Among the 15 miRNAs investigated, miR-146a - 5p, miR-15a-5p were upregulated in wild-type and TLR2 -/- mice and miR-146a-5p, miR-30c-5p, let-7c-5p were upregulated in the TLR4 -/- mice compared to sham-infected controls. Notably, inflammatory miRNA miR-146a-5p was upregulated uniquely among the three different infection groups. The upregulated miRNAs (miR-146a, miR-15-a-5p, let-7c-5p) and downregulated miRNAs could be markers for TLRs-mediated induction of periodontitis.

Managing cardiovascular events, hyperglycemia, and obesity in type 2 diabetes through microRNA regulation linked to glucagon-like peptide-1 receptor agonists

BACKGROUND AND AIMS

Type 2 diabetes mellitus (T2DM) is usually complicated by cardiovascular diseases, hyperglycemia, and obesity, which worsen the outcome for the patient. Since recent evidence underlines the epigenetic role of glucagon-like peptide-1 receptor agonists (GLP-1RAs) in the management of these comorbidities, this study compared the effects of these agents, namely liraglutide, semaglutide, dulaglutide, and exenatide, on miRNA regulation in the management of T2DM.

RESULTS

GLP-1RAs modify the expression of miRNAs involved in endothelial function, sugar metabolism, and adipogenesis, including but not limited to miR-27b, miR-130a, and miR-210. Baseline miR-15a-5p predict weight loss, while higher miR-378-3p and miR-126-3p levels are related to better glycemic control and lower HbA1c and FPG at one year post-treatment. miR-375-5p was also reported as a predictor of HbA1c levels. Liraglutide has a protecting effect against pancreatic β-cell apoptosis by downregulating miR-139-5p. The highly-expressed miR-375 in pancreatic islets can be considered as a biomarker for assessing the cytoprotective action of GLP-1RAs on β-cells. GLP-1RAs also enhance β-cell responsiveness by promoting GLP-1 receptor expression through the suppression of miR-204. While semaglutide, semaglutide, and dulaglutide reduce both systolic and diastolic blood pressures, lixisenatide and exenatide QW did not reveal such an effect. The long-acting exenatide-induced miR-29b-3p is required for the protection against diabetic cardiomyopathy. Liraglutide modulates critical regulators of endothelial cell function and atherosclerosis, including miR-93-5p, miR-26a-5p, and miR-181a-5p. Eventually, GLP-1RAs regulation of exosomal miRNAs, such as miR-192, implicated in the development of fibrosis and inflammation in T2DM micro-cardiovascular outcomes like DKD and DR.

CONCLUSION

Additional studies will be needed in the elucidation of the relations between GLP-1RA-induced miRNAs and clinical-laboratory findings concerning the diverse populations, gender, and presence of other comorbid states in treated patients with T2DM.

The Interactive Effects of Fruit Intake Frequency and Serum miR-484 Levels as Biomarkers for Incident Type 2 Diabetes in a Prospective Cohort of the Spanish Adult Population: The Di@bet.es Study

Background/Objectives: Although evidence suggests that miR-484 and several fruit components are involved in glucose metabolism and insulin resistance metabolic pathways, the relationship between serum miR-484 levels and fruit consumption in relation to the risk of Type 2 diabetes (T2DM) remains elusive. The aim of this study was to evaluate the possible association between serum miR-484 levels and fruit intake frequency with the risk of T2DM in the Spanish adult population. Methods: 2234 subjects from the Di@bet.es cohort study without T2DM at baseline were studied. Socio-demographic, anthropometric and clinical data were recorded, as well as responses to a questionnaire on habits, including frequency of fruit consumption (daily vs. occasional). T2DM was diagnosed at baseline and after 7.5 years of follow-up. Baseline serum miR-484 levels were measured using real-time qPCR and categorized based on the 25th percentile. Association analyses were performed using logistic regression models adjusted for potential confounders. Interaction effects were evaluated on the multiplicative and additive scales. Results: There was no association between miR-484 levels and fruit intake frequency. Categorized miR-484 levels and fruit consumption were inversely and independently associated with the likelihood of incident T2DM. Analysis of the interaction effect suggests the presence of both positive multiplicative and additive interactions between miR-484 categories and fruit consumption frequency. Conclusions: Our study demonstrates a protective effect of daily fruit intake and high miR-484 levels regarding the risk of T2DM and supports the nutritional recommendations advocating daily fruit consumption. This study also suggests that the combined effect of low miR-484 levels and occasional fruit intake may increase the risk of T2DM beyond their independent effects.

Decreased Serum Insulin Receptor Messenger RNA Level in H. pylori IgG Seropositive Type 2 Diabetic Patients

Background

Helicobacter pylori (H. pylori) is a known gastro-intestinal pathogen but implicated in extra-gastric diseases. The relationship between H. pylori infection and type 2 diabetes (T2DM) remains insufficiently elucidated, particularly in terms of molecular mediators such as microRNAs (miRNAs) and messenger RNAs (mRNAs).

Objective

We aimed to characterize expression pattern of insulin signalling mRNAs and targeted miRNAs in T2DM patients exposed to H. pylori infection.

Methods

We conducted a cross-sectional study among patients diagnosed with type 2 diabetes mellitus and were aged 18 to 60 years. Overnight fasting blood samples were collected and processed for plasma and serum. The plasma samples were used for glucose estimation and the serum used for H. pylori IgG screening. Total RNA was extracted from the serum with commercial kit, and mRNAs and miRNAs quantified by RT-qPCR with specific primers and under predetermined amplification conditions. Clinical data were obtained from medical records of patients.

Results

Among 351 patients enrolled, 267 (76.1%) were females, 224 (63.8%) were married, and 79 (22.5%) had tertiary education. Expression level of insulin receptor mRNA was significantly lower in H. pylori positive T2DM patients compared to H. pylori negative (P < .05). There was no evidence of a difference in insulin receptor substrate 1 mRNA level (P > .05). Although not statistically significant, the expression levels of miRNA-222 and miRNA-155 in the patients exposed to H. pylori were higher than that of the unexposed group (P > .05).

Conclusions

We found a significantly reduced serum insulin receptor messenger RNA level and higher levels of miRNA-222 and miRNA-155 in H. pylori exposed T2DM patients. The findings suggest a possible role of the infection in insulin signalling alteration in the patients.

Unraveling the mechanisms of hepatogenous diabetes and its therapeutic perspectives

The review focused mainly on the pathogenesis of hepatogenous diabetes (HD) in liver cirrhosis (LC). This review reveals parallels between the mechanisms of metabolic dysfunction observed in LC and type II diabetes (T2DM), suggesting a shared pathway leading to HD. It underscores the role of insulin in HD pathogenesis, highlighting key factors such as insulin signaling, glucose metabolism, insulin resistance (IR), and the influence of adipocytes. Furthermore, the impact of adipose tissue accumulation, fatty acid metabolism, and pro-inflammatory cytokines like Tumor necrosis factor-α (TNF-α) on IR are discussed in the context of HD. Altered signaling pathways, disruptions in the endocrine system, liver inflammation, changes in muscle mass and composition, and modifications to the gut microbiota collectively contribute to the complex interplay linking cirrhosis and HD. This study highlights how important it is to identify and treat this complex condition in cirrhotic patients by thoroughly analyzing the link between cirrhosis, IR, and HD. It also emphasizes the vitality of targeted interventions. Cellular and molecular investigations into IR have revealed potential therapeutic targets for managing and preventing HD.

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.

Rephrasing the 'David-Goliath' story in the field of diabetes

Diabetes Mellitus has become a serious threat to public health. This non-communicable disease is spreading like wildfire to shape in the form of a global pandemic. It affects several organs during silent progression in the human body. The pathophysiological fallouts associate dysregulation of numerous cellular pathways. MicroRNAs have emerged as potent gene expression regulators by post-transcriptional mechanisms in the last two decades or so. Many microRNAs display differential expression patterns under hyperglycemia affecting coupled cellular signaling cascades. The present article attempts to unfold the involvement of microRNAs as biomarkers in diabetic conditions in current scenarios identifying their therapeutic significance.

MicroRNA-29a and microRNA-122 expressions and other inflammatory markers among obese children with diabetes

OBJECTIVES

This study was conducted to study the expression of both microRNA-29a and microRNA-122, and serum levels of sestrin-2, interleukin-6 (IL-6), and other inflammatory markers among obese children with/and without diabetes mellitus.

METHODS

One hundred obese children with diabetes in addition to 100 age- and sex-matched obese children without diabetes, and 100 age- and sex-matched apparently healthy children were included in the study. Expressions of both microRNA-29a and microRNA-122, and serum levels of sestrin-2, IL-6, tumor necrosis factor-α (TNF-α), and high sensitive-CRP (hsCRP) were measured for all included study populations.

RESULTS

Study results showed that the expressions of both microRNA-29a and microRNA-122, serum levels of IL-6, TNF-α, and hsCRP were significantly higher among obese children with diabetes in comparison to both obese children without diabetes and healthy children. In contrast, serum sestrin level was significantly low among obese children with diabetes in comparison to the other study populations. Expressions of both microRNA-29a and microRNA-122 were correlated with waist circumference, BMI, total cholesterol, triglycerides, LDL-cholesterol, HbA1c, c-peptide, glucose, insulin, homeostatic model assessment-insulin resistance (HOMA-IR), IL-6, hsCRP, and TNF-α among obese children with diabetes. However, serum sestrin-2 level was correlated inversely with these parameters. Higher expressions of both microRNA-29a and microRNA-122 among obese children either with or without diabetes mellitus (DM) can suggest their roles in the development of obesity among children.

CONCLUSIONS

The study results can hypothesize that down-regulation of these micro-RNAs may solve this health problem with its sequelae, a hypothesis that needs more studies.

Unveiling the regulatory role of miRNAs in stroke pathophysiology and diagnosis

Stroke, a major global cause of mortality, leads to a range of problems for those who survive. Besides its brutal events, stroke also tends to have a characteristic of recurrence, making it a complex disease involving intricate regulatory networks. One of the major cellular regulators is the non-coding RNAs (ncRNA), specifically microRNAs (miRNAs), thus the possible functions of miRNAs in the pathogenesis of stroke are discussed as well as the possibility of using miRNA-based therapeutic approaches. Firstly, the molecular mechanisms by which miRNAs regulate vital physiological processes, including synaptic plasticity, oxidative stress, apoptosis, and the integrity of the blood-brain barrier (BBB) are reviewed. The miRNA indirectly impacts stroke outcomes by regulating BBB function and angiogenesis through the targeting of transcription factors and angiogenic factors. In addition, the tendency for some miRNAs to be upregulated in response to hypoxia, which is a prevalent phenomenon in stroke and various neurological disorders, highlights the possibility that it controls hypoxia-inducible factor (HIF) signaling and angiogenesis, thereby influencing the integrity of the BBB as examples of the discussed mechanisms. Furthermore, this review explores the potential therapeutic targets that miRNAs may offer for stroke recovery and highlights their promising capacity to alleviate post-stroke complications. This review provides researchers and clinicians with valuable resources since it attempts to decipher the complex network of miRNA-mediated mechanisms in stroke. Additionally, the review addresses the interplay between miRNAs and stroke risk factors as well as clinical applications of miRNAs as diagnostic and prognostic markers.

Non-coding RNAs expression in SARS-CoV-2 infection: pathogenesis, clinical significance, and therapeutic targets

The coronavirus disease 2019 (COVID-19) pandemic has been looming globally for three years, yet the diagnostic and treatment methods for COVID-19 are still undergoing extensive exploration, which holds paramount importance in mitigating future epidemics. Host non-coding RNAs (ncRNAs) display aberrations in the context of COVID-19. Specifically, microRNAs (miRNAs), long non-coding RNAs (lncRNAs), and circular RNAs (circRNAs) exhibit a close association with viral infection and disease progression. In this comprehensive review, an overview was presented of the expression profiles of host ncRNAs following SARS-CoV-2 invasion and of the potential functions in COVID-19 development, encompassing viral invasion, replication, immune response, and multiorgan deficits which include respiratory system, cardiac system, central nervous system, peripheral nervous system as well as long COVID. Furthermore, we provide an overview of several promising host ncRNA biomarkers for diverse clinical scenarios related to COVID-19, such as stratification biomarkers, prognostic biomarkers, and predictive biomarkers for treatment response. In addition, we also discuss the therapeutic potential of ncRNAs for COVID-19, presenting ncRNA-based strategies to facilitate the development of novel treatments. Through an in-depth analysis of the interplay between ncRNA and COVID-19 combined with our bioinformatic analysis, we hope to offer valuable insights into the stratification, prognosis, and treatment of COVID-19.

MiR-217 Regulates SIRT1 Expression and Promotes Inflammatory and Apoptotic Responses in Osteoarthritis

Previous studies have reported miR-217 uregulation in age-related pathologies. We investigated the impact of miR-217-5p on sirtuin 1 (SIRT1) regulation in human osteoarthritic (OA) chondrocytes. MiR-217 target enrichment analyses were performed using three public databases, Gene Ontology and Kyoto Encyclopedia of Genes and Genomes. MiR-217-5p expression levels were quantified in normal and OA chondrocytes. SIRT1 expression levels, nuclear factor kappa-B p65 subunit (NF-κBp65) and p53 acetylation levels, and expression levels of OA-related pro-inflammatory markers [tumor necrosis factor α (TNFα), interleukin 1β (IL-1β), IL-6], pro-apoptotic markers [Bax, pro-caspase 3, cleaved caspase 3] and matrix regulators [matrix metalloproteinase (MMP)-1, MMP-13, MMP-9, Collagen 2 (COL2A1), Aggrecan (ACAN)] were evaluated in miR-217 mimic-treated and/or miR-217 inhibitor-treated OA chondrocytes, with/without subsequent treatment with siRNA against SIRT1 (siSIRT1). MiR-217-5p was upregulated in OA chondrocytes, while target prediction/enrichment analyses revealed SIRT1 as miR-217 target-gene. Deacetylation of NF-κBp65 and p53 in miR-217 inhibitor-treated OA chondrocytes was reversed by siSIRT1 treatment. MiR-217 inhibitor-treated OA chondrocytes showed increased COL2A1, ACAN and decreased IL-1β, IL-6, TNFα, Bax, cleaved caspase 3 and MMPs expression levels, which were reversed following miR-217 inhibitor/siSIRT1 treatment. Our findings highlight the impact of miR-217-5p on SIRT1 downregulation contributing to OA pathogenesis.

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.

Stem Cell Therapy in Critical Limb Ischemia

Critical limb ischemia (CLI), a serious outcome of peripheral artery disease, is frequently associated with morbid outcomes. The available treatment modalities do not provide satisfactory results, leading to marked morbidities such as joint contracture and amputations, resulting in a high economic burden. The peripheral vascular disease tends to cause more morbidity in patients with diabetes and atherosclerosis, given the pre-existing compromised perfusion of medium and small vessels in diabetic patients. With surgical procedures, the chance of vascular compromise further increases, inducing a significantly greater rate of amputation. Hence, the need for nonsurgical treatment modalities such as stem cell therapy (SCT), which promotes angiogenesis, is warranted. In CLI, SCT acts through neovascularization and the development of collateral arteries, which increases blood supply to the soft tissues of the ischemic limb, providing satisfactory outcomes. An electronic database search was performed in PubMed, SCOPUS, EMBASE, and ScienceDirect to identify published clinical trial data, research studies, and review articles on stem cell therapy in critical limb ischemia. The search resulted in a total of 2391 results. Duplicate articles screening resulted in 565 articles. In-depth screening of abstracts and research titles excluded 520 articles, yielding 45 articles suitable for full-text review. On review of full text, articles with overlapping and similar results were filtered, ending in 25 articles. SCT promotes arteriogenesis, and bone marrow-derived mesenchymal stromal cells produce significant effects like reduced morbidity, improved amputation-free survival (AFS ) rate, and improved distal perfusion even in "no-option" CLI patients. SCT is a promising treatment modality for CLI patients, even in those in whom endovascular and revascularization procedures are impossible. SCT assures a prolonged AFS rate, improved distal perfusion, improved walking distances, reduced amputation rates, and increased survival ratio, and is well-tolerated.

Therapeutic actions of tea phenolic compounds against oxidative stress and inflammation as central mediators in the development and progression of health problems: A review focusing on microRNA regulation

Many health problems including chronic diseases are closely associated with oxidative stress and inflammation. Tea has abundant phenolic compounds with various health benefits including antioxidant and anti-inflammatory properties. This review focuses on the present understanding of the impact of tea phenolic compounds on the expression of miRNAs, and elucidates the biochemical and molecular mechanisms underlying the transcriptional and post-transcriptional protective actions of tea phenolic compounds against oxidative stress- and/or inflammation-mediated diseases. Clinical studies showed that drinking tea or taking catechin supplement on a daily basis promoted the endogenous antioxidant defense system of the body while inhibiting inflammatory factors. The regulation of chronic diseases based on epigenetic mechanisms, and the epigenetic-based therapies involving different tea phenolic compounds, have been insufficiently studied. The molecular mechanisms and application strategies of miR-27 and miR-34 involved in oxidative stress response and miR-126 and miR-146 involved in inflammation process were preliminarily investigated. Some emerging evidence suggests that tea phenolic compounds may promote epigenetic changes, involving non-coding RNA regulation, DNA methylation, histone modification, ubiquitin and SUMO modifications. However, epigenetic mechanisms and epigenetic-based disease therapies involving phenolic compounds from different teas, and the potential cross-talks among the epigenetic events, remain understudied.