Short Report: Circulating microRNAs are associated with incident diabetes over 10 years in Japanese Americans

Exercise couples mitochondrial function with skeletal muscle fiber type via ROS-mediated epigenetic modification

Skeletal muscle is a heterogeneous tissue composed of different types of muscle fibers, demonstrating substantial plasticity. Physiological or pathological stimuli can induce transitions in muscle fiber types. However, the precise regulatory mechanisms behind these transitions remains unclear. This paper reviews the classification and characteristics of muscle fibers, along with the classical mechanisms of muscle fiber type transitions. Additionally, the role of exercise-induced muscle fiber type transitions in disease intervention is reviewed. Epigenetic pathways mediate cellular adaptations and thus represent potential targets for regulating muscle fiber type transitions. This paper focuses on the mechanisms by which epigenetic modifications couple mitochondrial function and contraction characteristics. Reactive Oxygen Species (ROS) are critical signaling regulators for the health-promoting effects of exercise. Finally, we discuss the role of exercise-induced ROS in regulating epigenetic modifications and the transition of muscle fiber types.

Prevalence of pre-diabetes in adults aged 25 - 45 years in a Durban-based clinical setting, South Africa: A retrospective study

AIM

Due to pre-diabetes being underexplored, its prevalence was investigated in study participants aged 25-45 years in a Durban-based tertiary-level clinical setting in South Africa.

METHODS

The study was done using a retrospective study design. Fasting blood samples from consented patients with no previous diagnosis of diabetes and within the specified age range were collected from King Edward Hospital in Durban. The pre-diabetes diagnosis was confirmed in participants with fasting glucose concentrations between 5.6 and 6.9 mmol/L and glycated haemoglobin (HbA1c) levels between 5.7 % and 6.4 % using the American Diabetes Association (ADA) and World Health Organisation (WHO) diagnosis criteria. The study participants' characterisation was stratified according to the diagnosis criterion, age, gender and ethnicity.

RESULTS

An alarming 68 % average pre-diabetes prevalence across ADA and WHO criteria in the Durban, eThekwini district sample population. The highest prevalence was recorded using the IFG criterion (83%) and the lowest when using the HbA1c criterion (54 %). Between the White, Black and Indian ethnic groups, the Indian group were more predisposed to pre-diabetes onset, with a prevalence of 62.7 %.

CONCLUSION

If pre-diabetes management is unattended, an unprecedented increase in metabolic disorders such as Type 2 Diabetes Mellitus (T2DM) and all-cause mortality incidence can be expected. Therefore, the study reveals a window of opportunity to intensify preventative measures and mitigate the incidence of T2DM.

Prevalence and correlates of pre-diabetes in adults of mixed ethnicities in the South African population: A systematic review and meta-analysis

INTRODUCTION

Pre-diabetes is a metabolic condition characterised by moderate glycaemic dysregulation and is a frontline risk factor for multiple metabolic complications such as type 2 diabetes mellitus. To the best of our knowledge, this will be the first systematic review and meta-analysis focusing on generating a comprehensive pooling of studies reporting on pre-diabetes prevalence in South Africa. Therefore, the review's purpose will be to screen and select reports that can be used to synthesise and provide the best estimate prevalence of pre-diabetes and its associated correlates in the South African population.

METHODS AND ANALYSIS

To determine the prevalence and correlates of pre-diabetes in South Africa, we searched PubMed, Web of Science, Google scholar and African Journal online for published or unpublished studies reporting the prevalence of pre-diabetes in South Africa starting from the year 2000 to 2020. Studies were assessed for eligibility by checking if they met the inclusion criteria.

RESULTS & CONCLUSION

The total number of studies deemed eligible is 13 and from these studies, an overall prevalence of pre-diabetes was reported to be 15,56% in the South African population. Hypertension, obesity and sedentary lifestyle were the common correlates recorded for the population of interest. Therefore, the review highlights the disturbingly high prevalence of pre-diabetes in South Africa and necessitates further investigations into the possible genetics, biochemical and hormonal changes in pre-diabetes.

ETHICS AND DISSEMINATION

The review will not require ethics clearance because non-identifiable data will be used. The review outcomes will give insight into the current burden that pre-diabetes has in South Africa.

PROSPERO REGISTRATION NUMBER

CRD42020182430.

Exosome-cargoed microRNAs: Potential therapeutic molecules for diabetic wound healing

Diabetic foot ulcers are one of the most common complications of diabetes, requiring repeated surgical intervention and leading to amputation. Owing to the lack of effective drugs, novel therapeutics need to be explored. Decreased angiogenic factors, endothelial cell dysfunction and vascular lumen stenosis impair angiogenesis in diabetic wounds. Exosome-cargoed microRNAs are emerging as pivotal regulators of angiogenesis during wound closure. Herein, we summarize the up-to-date knowledge of exosomal microRNAs in modulating angiogenesis and accelerating diabetic wound healing, as well as their targets and underlying mechanisms. Exosomal microRNAs could be therapeutics with negligible rejection complications and good compatibility to treat diabetic foot ulcers.

Associations of plasma miRNAs with waist circumference and insulin resistance among women with polycystic ovary syndrome - Pilot study

BACKGROUND

Insulin resistance (IR) and central obesity are common in polycystic ovary syndrome (PCOS), but pathomechanisms for IR in PCOS are not established. Circulating microRNAs (miRNAs) are non-invasive biomarkers of epigenetic regulation that may contribute to the pathogenesis of IR and central adiposity in PCOS.

METHODS

We conducted a pilot study to examine associations of circulating miRNAs with IR and central adiposity among women with PCOS (n = 11) using high-throughput miRNA sequencing. We fit generalized linear models examining associations of waist circumference and HOMA-IR with plasma miRNAs. We used false discovery rate (FDR)-adjusted cutoff p < 0.1 to correct for multiple testing. We used miRDB's Gene Ontology (GO) tool to identify predicted pathways for top hits.

RESULTS

Mean age and BMI of participants were 27.9 years and 32.5 kg/m2, respectively. Lower levels of miR-1294 were associated with higher waist circumference (β = -0.10, FDR = 0.095). While no miRNAs were associated with HOMA-IR at our FDR cut off <0.1, 11 miRNAs were associated with waist circumference and 14 miRNAs with HOMA-IR at unadjusted p < 0.01, including members of the highly conserved miR-17/92 cluster and miR-1294 (β = -0.10, p < 0.001). The GO analysis of miR-1294 identified 54 overrepresented pathways, including "negative regulation of insulin receptor signaling" (FDR = 0.019), and 6 underrepresented pathways.

CONCLUSIONS

Plasma miR-1294 along with members of the miR-17/92 cluster and miRNAs involved in insulin signaling may be associated with central obesity and insulin resistance in PCOS. Larger studies among women with and without PCOS are needed to validate these findings.

Lycium barbarum polysaccharides attenuates high glucose-induced diabetic retinal angiogenesis by rescuing the expression of miR-15a-5p in RF/6A cells

ETHNOPHARMACOLOGICAL RELEVANCE

Lycium barbarum L., a classical traditional Chinese Medicine, has long been used to treat ocular diseases. Lycium barbarum polysaccharides (LBP) is an effective component of Lycium barbarum L. with a wide range of pharmacological activities. This research aims to investigate the inhibition of high glucose-induced angiogenesis by LBP in RF/6A cells.

MATERIALS AND METHODS

A high-glucose-induced angiogenesis model was established using monkey retinal vascular endothelial (RF/6A) cells. Different dosages administration times of LBP and glucose concentrations were tested. Under the optimized conditions, RF/6A cells were treated with LBP for 48 h, followed by another 48-h culture in high glucose (25 mmol/L) medium. The effect and mechanism of LBP were investigated following the treatment.

RESULTS

The expression of miR-15a-5p and miR-15a-3p in RF/6A cells decreased significantly after 48 h of 25 or 50 mmol/L high glucose treatment. The expression of miR-15a-5p was higher than that of miR-15a-3p. Mimic-miR-15a-5p or 600 mg/L LBP could increase the apoptosis of cells and the total length of vascular branches. The expression of VEGFA, VEGFR2, and ANG2 proteins was reduced, while the expression of ANG1 protein was elevated. Expression of ASM mRNA and protein was also inhibited.

CONCLUSIONS

LBP attenuates diabetic retinal angiogenesis by rescuing the expression of miR-15a-5p in RF/6A cells.

MiR-20b-5p contributes to the dysfunction of vascular smooth muscle cells by targeting MAGI3 in hypertension

INTRODUCTION

MicroRNAs (miRNAs), have been frequently reported to regulate various diseases including hypertension. However, the biological role and regulatory mechanism of miR-20b-5p are unclear in hypertension. The current study aimed to investigate the role of miR-20b-5p in hypertension.

METHODS

Bioinformatics analysis (starBase: http://starbase.sysu.edu.cn ) and a wide range of experiments including blood pressure detection, morphometric sampling by electron microscopy, real-time quantitative polymerase chain reaction (RT-qPCR), CCK-8, western blot, luciferase reporter, hematoxylin and eosin (H&E) staining and Masson trichrome staining assays were used to explore the function and mechanism of miR-20b-5p in hypertension.

RESULTS

MiR-20b-5p level was significantly upregulated in Spontaneously hypertensive rats' (SHRs') thoracic aortic vascular tissues. In function, miR-20b-5p silencing inhibited the proliferation and migration of aortic smooth muscle cells (ASMCs) of SHRs. In mechanism, we predicted 10 potential target mRNAs for miR-20b-5p. After prediction by bioinformatics, MAGI3 was validated to bind with miR-20b-5p. Rescue assays showed that MAGI3 silencing reversed the inhibitive influence of miR-20b-5p depletion on cell proliferation and migration.

CONCLUSIONS

MiR-20b-5p contributed to the dysfunction of ASMCs by targeting MAGI3 in hypertension. This new discovery provided a potential novel insight for hypertension treatment.

Circulating microRNA profile in humans and mice with congenital GH deficiency

Reduced inflammation, increased insulin sensitivity, and protection against cancer are shared between humans and mice with GH/IGF1 deficiency. Beyond hormone levels, miRNAs are important regulators of metabolic changes associated with healthy aging. We hypothesized that GH deficiency in humans alters the abundance of circulating miRNAs and that a subset of those miRNAs may overlap with those found in GH-deficient mice. In this study, subjects with untreated congenital isolated GH deficiency (IGHD; n = 23) and control subjects matched by age and sex (n = 23) were recruited and serum was collected for miRNA sequencing. Serum miRNAs from young (6 month) and old (22 month) Ames dwarf (df/df) mice with GH deficiency and their WT littermates (n = 5/age/genotype group) were used for comparison. We observed 14 miRNAs regulated with a genotype by age effect and 19 miRNAs regulated with a genotype effect independent of age in serum of IGHD subjects. These regulated miRNAs are known for targeting pathways associated with longevity such as mTOR, insulin signaling, and FoxO. The aging function was overrepresented in IGHD individuals, mediated by hsa-miR-31, hsa-miR-146b, hsa-miR-30e, hsa-miR-100, hsa-miR-181b-2, hsa-miR-195, and hsa-miR-181b-1, which target the FoxO and mTOR pathways. Intriguingly, miR-181b-5p, miR-361-3p, miR-144-3p, and miR-155-5p were commonly regulated in the serum of humans and GH-deficient mice. In vitro assays confirmed target genes for the main up-regulated miRNAs, suggesting miRNAs regulated in IGHD individuals can regulate the expression of age-related genes. These findings indicate that systemic miRNAs regulated in IGHD individuals target pathways involved in aging in both humans and mice.

MicroRNA Sequences Modulated by Beta Cell Lipid Metabolism: Implications for Type 2 Diabetes Mellitus

Alterations in lipid metabolism within beta cells and islets contributes to dysfunction and apoptosis of beta cells, leading to loss of insulin secretion and the onset of type 2 diabetes. Over the last decade, there has been an explosion of interest in understanding the landscape of gene expression which influences beta cell function, including the importance of small non-coding microRNA sequences in this context. This review sought to identify the microRNA sequences regulated by metabolic challenges in beta cells and islets, their targets, highlight their function and assess their possible relevance as biomarkers of disease progression in diabetic individuals. Predictive analysis was used to explore networks of genes targeted by these microRNA sequences, which may offer new therapeutic strategies to protect beta cell function and delay the onset of type 2 diabetes.

Effects of physical activity on cell-to-cell communication during type 2 diabetes: A focus on miRNA signaling

Type 2 diabetes (TD2) is a progressive disease characterized by hyperglycemia that results from alteration in insulin secretion, insulin resistance, or both. A number of alterations involving different tissues and organs have been reported to the development and the progression of T2D, and more relevantly, through cell-to-cell communication pathways. Recent studies demonstrated that miRNAs are considerably implicated to cell-to-cell communication during T2D. Physical activity (PA) is associated with decreasing risks of developing T2D and acts as insulin-like factor. Cumulative evidence suggests that this effect could be mediated in part through improving insulin sensitivity in T2D and obese patients and modulating miRNAs synthesis and release in healthy patients. Therefore, the practice of PA should ideally be established before the initiation of T2D. This review describes cell-to-cell communications involved in the pathophysiology of T2D during PA.

Circulating microRNA-194 levels in Chinese patients with diabetic kidney disease: a case-control study

OBJECTIVE

MicroRNAs (miRNAs) regulate gene expression and are involved in diabetic kidney disease (DKD) pathogenesis. We investigated circulating miRNA-194 levels as a biomarker of DKD prevalence and incidence, and the relationship between miRNA-194 and CCAAT/enhancer binding protein (C/EBP) homologous protein (CHOP).

METHODS

We recruited 136 type-2 diabetes mellitus (T2DM) patients at the First People's Hospital of Lianyungang and 127 healthy individuals. Circulating miRNA-194 and CHOP levels were measured using quantitative reverse transcription qRT-PCR and enzyme-linked immunosorbent assay (ELISA), respectively. Anthropometric and biochemistry measurements were also made.

RESULTS

T2DM patients showed higher circulating miRNA-194 (p = 0.029) and lower circulating CHOP (p < 0.001) levels than controls. Circulating miRNA-194 levels were significantly higher in T2DM patients with a microalbumin/creatinine ratio (UmALB/Cr) ⩾ 300 mg/g (p < 0.001). In addition, there were significant intergroup differences in the circulating CHOP concentrations (p = 0.005). Bivariate analysis revealed that circulating miR-194 levels were negatively correlated with alpha-fetoprotein and CHOP levels (r = -0.222, -0.301; p = 0.018, 0.001, respectively), but positively correlated with fasting glucose, UmALB/Cr, Cr, Cystatin C, quantitative insulin check index (QUICKI) (r = 0.193, 0.446, 0.260, 0.339, and 0.250, respectively; p = 0.036, <0.001, 0.005, <0.001, and 0.006, respectively), particularly UmALB/Cr and Cystatin C (p < 0.001). Logistic regression analysis after adjusting for covariates associated with UmALB/Cr identified duration of T2DM, systolic blood pressure, Cr, estimated glomerular filtration rate, and waist circumference as independent factors associated with T2DM patients with UmALB/Cr > 300 (p = 0.030, 0.013, <0.001, <0.001, and 0.031, respectively).

CONCLUSION

Circulating miRNA-194 levels could be a novel biomarker for DKD.