Circulating MicroRNA-21 is Downregulated in Patients with Metabolic Syndrome

The Single Nucleotide Polymorphisms (rs1292037 and rs13137) in miR-21 Were Associated with T2DM in a Chinese Population

BACKGROUND

Insulin receptor (INSR), insulin receptor substrate (IRS) and glucose transporter 4 (GLUT4) play important roles in the insulin resistance pathway. The microRNA (miRNA or miR) involved in INSR, IRS or GLUT4 could be associated with the development of type 2 diabetes (T2DM).

METHODS

The aim of this study was to investigate the association of T2DM with 12 single nucleotide polymorphisms (SNPs) in 7 miRNAs (miR-195, miR-126, miR-144, miR-155, miR-21, miR-93 and miR-222) involved in the insulin resistance pathway. A total of 1593 subjects with T2DM and 1656 nondiabetic subjects were genotyped. Then, the associations of these SNPs with the development of T2DM and individual metabolic traits were evaluated, such as fasting plasma glucose (FPG) and glycosylated haemoglobin (HbA1C).

RESULTS

Our data showed that the C allele of rs1292037 in miR-21 could increase the risk of developing T2DM (P = 0.002, OR = 1.17; 95% CI: 1.06-1.29). In addition, the T allele of rs13137 in miR-21 could be a risk factor for T2DM (P = 0.003, OR = 1.16; 95% CI: 1.05-1.28). According to inheritance mode analysis, compared with the T/T-T/C genotype, the C/C genotype of rs1292037 showed a risk effect in T2DM in the recessive mode (P = 0.001, OR = 1.35; 95% CI: 1.13-1.63). For rs13137, compared with the A/A-A/T genotype, the T/T genotype also showed a risk effect in T2DM in the recessive mode (P = 0.001, OR = 1.35; 95% CI: 1.13-1.62). Moreover, in the nondiabetic group, compared with the rs78312845 A/G (FPG = 5.177±0.488mmol/L; HbA1C = 5.147±0.293%) and A/A genotypes (FPG = 5.155±0.486mmol/L; HbA1C = 5.136±0.299%), the G/G genotype (FPG = 4.887±0.482mmol/L; HbA1C = 4.960±0.397%) was associated with lower FPG (P = 0.012 and 0.019) and HbA1C (P = 0.008 and 0.011).

CONCLUSION

Our results revealed that rs1292037 and rs13137 in miR-21 were associated with T2DM susceptibility in a Han Chinese population. Moreover, the rs78312845 in miR-195 contributed to the level of FPG and HbA1C in nondiabetic group in the Han Chinese population.

MicroRNAs: The Link between the Metabolic Syndrome and Oncogenesis

Metabolic syndrome (MetS) represents a cluster of disorders that increase the risk of a plethora of conditions, in particular type two diabetes, cardiovascular diseases, and certain types of cancers. MetS is a complex entity characterized by a chronic inflammatory state that implies dysregulations of adipokins and proinflammatory cytokins together with hormonal and growth factors imbalances. Of great interest is the implication of microRNA (miRNA, miR), non-coding RNA, in cancer genesis, progression, and metastasis. The adipose tissue serves as an important source of miRs, which represent a novel class of adipokines, that play a crucial role in carcinogenesis. Altered miRs secretion in the adipose tissue, in the context of MetS, might explain their implication in the oncogenesis. The interplay between miRs expressed in adipose tissue, their dysregulation and cancer pathogenesis are still intriguing, taking into consideration the fact that miRNAs show both carcinogenic and tumor suppressor effects. The aim of our review was to discuss the latest publications concerning the implication of miRs dysregulation in MetS and their significance in tumoral signaling pathways. Furthermore, we emphasized the role of miRNAs as potential target therapies and their implication in cancer progression and metastasis.

Epigenetics, microRNA and Metabolic Syndrome: A Comprehensive Review

Epigenetics refers to the DNA chemistry changes that result in the modification of gene transcription and translation independently of the underlying DNA coding sequence. Epigenetic modifications are reported to involve various molecular mechanisms, including classical epigenetic changes affecting DNA methylation and histone modifications and small RNA-mediated processes, particularly that of microRNAs. Epigenetic changes are reversible and are closely interconnected. They are recognised to play a critical role as mediators of gene regulation, and any alteration in these mechanisms has been identified to mediate various pathophysiological conditions. Moreover, genetic predisposition and environmental factors, including dietary alterations, lifestyle or metabolic status, are identified to interact with the human epigenome, highlighting the importance of epigenetic factors as underlying processes in the aetiology of various diseases such as MetS. This review will reflect on how both the classical and microRNA-regulated epigenetic changes are associated with the pathophysiology of metabolic syndrome. We will then focus on the various aspects of epigenetic-based strategies used to modify MetS outcomes, including epigenetic diet, epigenetic drugs, epigenome editing tools and miRNA-based therapies.

A Comprehensive miRNome Analysis of Macrophages Isolated from db/db Mice and Selected miRNAs Involved in Metabolic Syndrome-Associated Cardiac Remodeling

Cardiac macrophages are known from various activities, therefore we presume that microRNAs (miRNAs) produced or released by macrophages in cardiac tissue have impact on myocardial remodeling in individuals with metabolic syndrome (MetS). We aim to assess the cardiac macrophage miRNA profile by selecting those miRNA molecules that potentially exhibit regulatory functions in MetS-related cardiac remodeling. Cardiac tissue macrophages from control and db/db mice (an animal model of MetS) were counted and sorted with flow cytometry, which yielded two populations: CD45+CD11b+CD64+Ly6Chi and CD45+CD11b+CD64+Ly6Clow. Total RNA was then isolated, and miRNA expression profiles were evaluated with Next Generation Sequencing. We successfully sequenced 1400 miRNAs in both macrophage populations: CD45+CD11b+CD64+Ly6Chi and CD45+CD11b+CD64+Ly6Clow. Among the 1400 miRNAs, about 150 showed different expression levels in control and db/db mice and between these two subpopulations. At least 15 miRNAs are possibly associated with MetS pathology in cardiac tissue due to direct or indirect regulation of the expression of miRNAs for proteins involved in angiogenesis, fibrosis, or inflammation. In this paper, for the first time we describe the miRNA transcription profile in two distinct macrophage populations in MetS-affected cardiac tissue. Although the results are preliminary, the presented data provide a foundation for further studies on intercellular cross-talk/molecular mechanism(s) involved in the regulation of MetS-related cardiac remodeling.

Evaluation of the Possible Role of miRNAs in Chemical Allergen Potency

Objectives

MicroRNAs (miRNAs) are short, endogenous noncoding RNA molecules that can bind to certain parts of target mRNAs, thereby regulating gene expression. Studies showed that miRNAs could be up- or downregulated in different allergic skin conditions but there is still need for further studies. The aim of this study was to investigate the expression of miRNAs in response to the common contact allergen Bandrowski's base (BB), the principal allergen in patients reacting to p-phenylenediamine (PPD).

Materials and Methods

The human promyelocytic cell line THP-1 was exposed to BB at a concentration of 1 μg/mL for 24, 48, and 72 h. The dose was selected from the results of cytotoxicity assays. RNA was purified and miRNA expression profile and real-time polymerase chain reaction (RTPCR) were performed to identify up- or downregulated miRNAs and confirm their modulations.

Results

Among the different modulated miRNAs, the upregulation of miRNA-155 and the downregulation of miRNA-21 were found to be important because these are related to immune system. This expression profile of miRNAs was also confirmed by RT-PCR.

Conclusion

These preliminary results showed that miR-155 and miR-21 may play a role in the pathogenesis of allergic contact dermatitis, but further studies are needed to clarify their definite roles.

Circulating microRNAs and endothelial cell migration rate are associated with metabolic syndrome and fitness level in postmenopausal African American women

Postmenopausal African American women are at elevated risk for metabolic syndrome (MetS), which predisposes them to cardiovascular disease and other chronic diseases. Circulating microRNAs (ci-miR) are potential mediators of cardiometabolic diseases also impacted by cardiorespiratory fitness (CRF) level. Using real-time quantitative PCR, we compared the expression of vascular-related ci-miRs (miR-21-5p, miR-92a-3p, miR-126-5p, miR-146a-5p, miR-150-5p, miR-221-3p) in sedentary, overweight/obese, postmenopausal African American women based on 1) presence (n = 31) or absence (n = 42) of MetS and 2) CRF level (VO2peak ) (Very Low < 18.0 mL·kg-1 ·min-1 [n = 31], Low = 18.0-22.0 mL·kg-1 ·min-1 [n = 24], or Moderate >22.0 mL·kg-1 ·min-1 [n = 18]). Endothelial migration rate in response to subjects' serum was assessed to determine the effect of circulating blood-borne factors on endothelial repair. Ci-miR-21-5p was the only ci-miR that differed between women with MetS compared to those without MetS (0.93 ± 0.43 vs. 1.28 ± 0.71, P = 0.03). There were borderline significant differences (P = 0.06-0.09) in ci-miR-21-5p, 126-5p, and 221-3p levels between the CRF groups, and these three ci-miRs correlated with VO2peak (r = -0.25 to -0.28, P < 0.05). Endothelial migration rate was impaired in response to serum from women with MetS compared to those without after 16-24 h. Serum from women with Moderate CRF induced greater endothelial migration than the Very Low and Low CRF groups after 4 and 16-24 h, that was also not different from a young, healthy reference group. Ci-miR-21-5p is lower in postmenopausal African American women with MetS, while ci-miRs-21-5p, 126-5p, and 221-3p are associated with CRF. Factors which impair endothelial cell migration rate are present in serum of women with MetS, though having Moderate CRF may be protective.

Relationship of Circulating miRNAs with Insulin Sensitivity and Associated Metabolic Risk Factors in Humans

BACKGROUND

Insulin resistance disrupts metabolic processes and leads to various chronic disease states such as diabetes and metabolic syndrome (MetS). However, the mechanism linking insulin resistance with cardiometabolic disease pathophysiology is still unclear. One possibility may be through circulating microRNAs (c-miRs), which can alter gene expression in target tissues. Our goal was to assess the relationship of c-miRs with insulin sensitivity, as measured by the gold standard, hyperinsulinemic-euglycemic clamp technique.

METHODS

Eighty-one nondiabetic, sedentary, and weight-stable patients across a wide range of insulin sensitivities were studied. Measurements were taken for blood pressure, anthropometric data, fasting glucose and lipids, and insulin sensitivity measured by clamp. After an initial screening array to identify candidate miRs in plasma, all samples were assessed for relationships between these c-miRs and insulin sensitivity, as well as associated metabolic factors.

RESULTS

miR-16 and miR-107 were positively associated with insulin sensitivity (R2 = 0.09, P = 0.0074 and R2 = 0.08, P = 0.0417, respectively) and remained so after adjustment with body mass index (BMI). After adjusting for BMI, miR-33, -150, and -222 were additionally found to be related to insulin sensitivity. Regarding metabolic risk factors, miR-16 was associated with waist circumference (r = -0.25), triglycerides (r = -0.28), and high-density lipoprotein (r = 0.22), while miR-33 was inversely associated with systolic blood pressure (r = -0.29). No significant relationships were found between any candidate c-miRs and BMI, diastolic blood pressure, or fasting glucose.

CONCLUSIONS

Our results show that relative levels of circulating miR-16, -107, -33, -150, and -222 are associated with insulin sensitivity and metabolic risk factors, and suggest that multiple miRs may act in concert to produce insulin resistance and the clustering of associated traits that comprise the MetS. Therefore, miRs may have potential as novel therapeutic targets or agents in cardiometabolic disease.

Circulating miRNAs and miRNA shuttles as biomarkers: Perspective trajectories of healthy and unhealthy aging

Human aging is a lifelong process characterized by a continuous trade-off between pro-and anti-inflammatory responses, where the best-adapted and/or remodeled genetic/epigenetic profile may develop a longevity phenotype. Centenarians and their offspring represent such a phenotype and their comparison to patients with age-related diseases (ARDs) is expected to maximize the chance to unravel the genetic makeup that better associates with healthy aging trajectories. Seemingly, such comparison is expected to allow the discovery of new biomarkers of longevity together with risk factor for the most common ARDs. MicroRNAs (miRNAs) and their shuttles (extracellular vesicles in particular) are currently conceived as those endowed with the strongest ability to provide information about the trajectories of healthy and unhealthy aging. We review the available data on miRNAs in aging and underpin the evidence suggesting that circulating miRNAs (and cognate shuttles), especially those involved in the regulation of inflammation (inflamma-miRs) may constitute biomarkers capable of reliably depicting healthy and unhealthy aging trajectories.