Emerging roles for miRNAs in the development, diagnosis, and treatment of diabetic nephropathy

miR-543 regulates high glucose-induced fibrosis and autophagy in diabetic nephropathy by targeting TSPAN8

BACKGROUND

Diabetic nephropathy (DN) is one of the most common and serious complications of diabetes, which can lead to renal failure and fatality. miRNAs are an important class of endogenous non-coding RNAs implicated in a wide range of biological processes and pathological conditions. This study aims to investigate the potential functional roles of miR-543 in DN and its underlying mechanisms.

METHODS

qRT-PCR was performed to detect the expression levels of miR-543 and TSPAN8 in kidney tissues of mice with DN. Western blot (WB) was used to measure the protein levels. CCK8 assay was employed to evaluate the proliferation of HK2 cells. Dual luciferase reporter assay was conducted to verify the functional interaction between miR-543 and TSpan8.

RESULTS

The downregulation of miR-543 and upregulation of TSPAN8 were observed in kidney tissues of mice with DN. miR-543 mimic significantly decreased cell proliferation and autophagy in high-glucose (HG)-induced HK2 cells, and promoted cell fibrosis. We further identified a putative binding site between miR-543 and TSPAN8, which was validated by Dual luciferase reporter assay. The treatment of miR-543 mimic and miR-543 inhibitor could reduce or increase TSPAN8 protein level respectively. We further showed that the overexpression of TSPAN8 could attenuate HG-induced cell injury by reducing fibrosis and increase autophagy. The effects of miR-543 mimic in proliferation, fibrosis, and autophagy were rescued by TSPAN8 overexpression.

CONCLUSIONS

Our study indicate that miR-543 mediates high-glucose induced DN via targeting TSPAN8. Interfering miR-543/TSPAN8 axis could serve as potential approach to ameliorate DN.

Differential expression of micro RNA-29 family in non-diabetic adults of diabetic and non-diabetic parents

OBJECTIVE

MicroRNAs are known to regulate 60% of genes at post translational level. MicroRNAs including Micro RNA-29 family play a vital role in cellular activities and have validate role in numerous metabolic disorders inclusive of diabetes mellitus and its complications. While micro RNA profile changes years before the occurrence of disease. This cross-sectional study was conducted in non-diabetic adults of diabetic and non-diabetic parents to explore the early changes in expression of micro RNA-29 family as it can be served as early biomarker of type 2 diabetes in non-diabetic adults. This study was conducted from January 2019 to January 2021. Micro RNA was extracted from plasma of 50 participants and expression was compared through qPCR. While data was analyzed through SPSS version 21.0.

RESULTS

29a and 29b had lower expression in participants with family history of DM compared to those having no family history of DM (P < 0.0001). While micro RNA 29c was found to be significantly higher in participants with positive family history of type 2 diabetes as compared to those without family history of diabetes (P = 0.001).

Long non-coding RNA MALAT1 and microRNA-499a expression profiles in diabetic ESRD patients undergoing dialysis: a preliminary cross-sectional analysis

Background: Circulating non-coding RNAs (ncRNAs) have been implicated in health and disease. This study aimed to evaluate the serum expression profile of microRNA-499a (miR-499a) and its selected bioinformatically predicted partner long-ncRNA MALAT1 (metastasis-associated lung adenocarcinoma transcript 1) in diabetes-related end-stage renal disease (ESRD) patients and to correlate the expressions with the patients' clinicolaboratory data.Subjects and methods: Real-time quantitative polymerase chain reaction was applied in diabetics with and without ESRD (n = 90 for each).Results: Serum MALAT1 expression levels were increased in the ESRD group relative to diabetics without ESRD with median (quartile) values of 10.5 (1.41-126.7) (p < .001). However, miR-499a levels were decreased in more than half of ESRD patients with a median of 0.96 (0.13-3.14). Both MALAT1 and miR-499a expression levels were inversely correlated in the ESRD patient-group.Conclusions: MALAT1 up-regulation and miR-499 down-regulation might be involved in diabetic nephropathy-related ESRD pathogenesis. Functional validation studies are warranted to confirm the MALAT1/miR-499a partnership.

Epigenetics and epigenomics in diabetic kidney disease and metabolic memory

The development and progression of diabetic kidney disease (DKD), a highly prevalent complication of diabetes mellitus, are influenced by both genetic and environmental factors. DKD is an important contributor to the morbidity of patients with diabetes mellitus, indicating a clear need for an improved understanding of disease aetiology to inform the development of more efficacious treatments. DKD is characterized by an accumulation of extracellular matrix, hypertrophy and fibrosis in kidney glomerular and tubular cells. Increasing evidence shows that genes associated with these features of DKD are regulated not only by classical signalling pathways but also by epigenetic mechanisms involving chromatin histone modifications, DNA methylation and non-coding RNAs. These mechanisms can respond to changes in the environment and, importantly, might mediate the persistent long-term expression of DKD-related genes and phenotypes induced by prior glycaemic exposure despite subsequent glycaemic control, a phenomenon called metabolic memory. Detection of epigenetic events during the early stages of DKD could be valuable for timely diagnosis and prompt treatment to prevent progression to end-stage renal disease. Identification of epigenetic signatures of DKD via epigenome-wide association studies might also inform precision medicine approaches. Here, we highlight the emerging role of epigenetics and epigenomics in DKD and the translational potential of candidate epigenetic factors and non-coding RNAs as biomarkers and drug targets for DKD.

miR-206 Inhibits Cell Proliferation and Extracellular Matrix Accumulation by Targeting Hypoxia-Inducible Factor 1-alpha (HIF-1α) in Mesangial Cells Treated with High Glucose

Background

The goal of this study was to investigate the expression of miR-206 in human glomerular mesangial cells (hMCs) treated by exposure to high glucose (HG) levels, to assess the influence of miR-206 on the proliferation and extracellular matrix (ECM) deposition of hMCs, and to investigate the potential mechanisms of action.

Material/Methods

The level of miR-206 was detected by RT-qPCR. MTT assay and colony formation assay were used to assess hMCs cell proliferation ability. Western blotting was carried out to measure the expression of related proteins. Bioinformatics software (http://www.targetscan.org) was used to predict the potential target genes of miR-206, and dual-luciferase reporter assay was used to confirm this prediction.

Results

Our results suggest that the level of miR-206 was downregulated in HG-treated hMCs. Cell proliferation was promoted in HG-induced hMCs, while this phenomenon was significantly reversed with miR-206 mimics. miR-206 mimics significantly enhanced p21 expression and decreased cyclin D1 and CDK2 expressions, but the opposite was found in HG-induced hMCs. Moreover, the level of ECM proteins was notably increased in hMCs treated with HG, which was also significantly reversed by miR-206 mimics. miR-206 inhibitor had the opposite effects. Furthermore, HIF-1α was found to be a direct target of miR-206, and was negatively regulated by miR-206 in hMCs. miR-206 can target HIF-1α to modulate cell proliferation and ECM accumulation.

Conclusions

Collectively, our results suggest that miR-206 plays a vital role in HG-treated hMCs through inhibiting cell proliferation and ECM accumulation, partly via targeting HIF-1α.

Diabetic nephropathy: The regulatory interplay between epigenetics and microRNAs

Diabetic nephropathy (DN) is still one of the leading causes of end-stage renal disease despite the emergence of different therapies to counter the metabolic, hemodynamic and fibrotic pathways, implicating a prominent role of genetic and epigenetic factors in its progression. Epigenetics is the study of changes in the expression of genes which may be inheritable and does not involve a change in the genome sequence. Thrust areas of epigenetic research are DNA methylation and histone modifications. Noncoding RNAs (ncRNAs), particularly microRNAs (miRNAs) control the expression of genes via post-transcriptional mechanisms. However, the regulation by epigenetic mechanisms and miRNAs are not completely distinct. A number of emerging reports have revealed the interplay between epigenetic machinery and miRNA expression, particularly in cancer. Further research has proved that a feedback loop exists between miRNA expression and epigenetic regulation in disorders including DN. Studies showed that different miRNAs (miR-200, miR-29 etc.) were found to be regulated by epigenetic mechanisms viz. DNA methylation and histone modifications. Conversely, miRNAs (miR-301, miR-449 etc.) themselves modulated levels of DNA methyltranferases (DNMTs) and Histone deacetylases (HDACs), enzymes vital to epigenetic modifications. With already few FDA approved epigenetic -modulating drugs (Vorinostat, Decitabine) in the market and miRNA therapeutic drugs under clinical trial it becomes imperative to analyze the possible interaction between the two classes of drugs in the modulation of a disease process. The purpose of this review is to articulate the interplay between miRNA expression and epigenetic modifications with a particular focus on its impact on the development and progression of DN.

Circulating miRNAs in diabetic kidney disease: case-control study and in silico analyses

AIMS

The aim of this study was to investigate a miRNA expression profile in type 1 diabetes mellitus (T1DM) patients with DKD (cases) or without this complication (controls).

METHODS

Expression of 48 miRNAs was screened in plasma of 58 T1DM patients (23 controls, 18 with moderate DKD, and 17 with severe DKD) using TaqMan Low Density Array cards (Thermo Fisher Scientific). Then, five of the dysregulated miRNAs were selected for validation in an independent sample of 10 T1DM controls and 19 patients with DKD (10 with moderate DKD and 9 with severe DKD), using RT-qPCR. Bioinformatic analyses were performed to explore the putative target genes and biological pathways regulated by the validated miRNAs.

RESULTS

Among the 48 miRNAs investigated in the screening analysis, 9 miRNAs were differentially expressed between DKD cases and T1DM controls. Among them, the five most dysregulated miRNAs were chosen for validation in an independent sample. In the validation sample, miR-21-3p and miR-378-3p were confirmed to be upregulated in patients with severe DKD, while miR-16-5p and miR-29a-3p were downregulated in this group compared to T1DM controls and patients with moderate DKD. MiR-503-3p expression was not validated. Bioinformatic analyses indicate that the four validated miRNAs regulate genes from PI3K/Akt, fluid shear stress and atherosclerosis, AGE-RAGE, TGF-β1, and relaxin signaling pathways.

CONCLUSIONS

Our study found four miRNAs differentially expressed in patients with severe DKD, providing significant information about the biological pathways in which they are involved.

MicroRNAs and diabetic kidney disease: Systematic review and bioinformatic analysis

MicroRNAs (miRNAs) are small non-coding RNAs that regulate gene expression. Emerging evidence has suggested a role for miRNAs in the development of diabetic kidney disease (DKD), indicating that miRNAs may represent potential biomarkers of this disease. However, results are still inconclusive. Therefore, we performed a systematic review of the literature on the subject, followed by bioinformatic analysis. PubMed and EMBASE were searched to identify all studies that compared miRNA expressions between patients with DKD and diabetic patients without this complication or healthy subjects. MiRNA expressions were analyzed in kidney biopsies, urine/urinary exosomes or total blood/plasma/serum. MiRNAs consistently dysregulated in DKD patients were submitted to bioinformatic analysis to retrieve their putative target genes and identify potentially affected pathways under their regulation. As result, twenty-seven studies were included in the systematic review. Among 151 dysregulated miRNAs reported in these studies, 6 miRNAs were consistently dysregulated in DKD patients compared to controls: miR-21-5p, miR-29a-3p, miR-126-3p, miR-192-5p, miR-214-3p, and miR-342-3p. Bioinformatic analysis indicated that these 6 miRNAs are involved in pathways related to DKD pathogenesis, such as apoptosis, fibrosis, and extracellular matrix accumulation. In conclusion, six miRNAs seem to be dysregulated in patients with different stages of DKD, constituting potential biomarkers of this disease.

Noncoding RNAs as therapeutic targets in early stage diabetic kidney disease

Diabetic kidney disease (DKD) is a major renal complication of diabetes that leads to renal dysfunction and end-stage renal disease (ESRD). Major features of DKD include accumulation of extracellular matrix proteins and glomerular hypertrophy, especially in early stage. Transforming growth factor-β plays key roles in regulation of profibrotic genes and signal transducers such as Akt kinase and MAPK as well as endoplasmic reticulum stress, oxidant stress, and autophagy related to hypertrophy in diabetes. Many drugs targeting the pathogenic signaling in DKD (mostly through protein-coding genes) are under development. However, because of the limited number of protein-coding genes, noncoding RNAs (ncRNAs) including microRNAs (miRNAs) and long noncoding RNAs (lncRNAs) are attracting more attention as potential new drug targets for human diseases. Some miRNAs and lncRNAs regulate each other (by hosting, enhancing transcription from the neighbor, hybridizing each other, and changing chromatin modifications) and create circuits and cascades enhancing the pathogenic signaling in DKD. In this short and focused review, the functional significance of ncRNAs (miRNAs and lncRNAs) in the early stages of DKD and their therapeutic potential are discussed.

New insights on microRNAs in diabetic nephropathy: potential biomarkers for diagnosis and therapeutic targets

Diabetic nephropathy (DN) is a severe complication of diabetes mellitus associated with the progressive deterioration of renal function. Although microalbuminuria is considered as a gold standard for DN diagnosis, it has limited predictive powers and specificity as a diagnostic tool for the early stage of DN. Therefore, new biomarkers are required for the early detection of DN. Studies using in vitro and in vivo models of DN have revealed an important role of microRNAs (miRNAs), short non-coding RNAs that modulate physiological and pathological processes by inhibiting target gene expression, in DN development. Recent studies have shown that the dysregulation of miRNAs, which is associated with the key features of DN, such as the mesangial expansion and accumulation of extracellular matrix proteins, is related to fibrosis and glomerular dysfunction. Thus, the up- and downregulation of miRNA expression in the renal tissue or biological fluids, including urine, may represent new biomarkers for the diagnosis and monitoring of DN progression. In this review, we highlight the significance of miRNAs as biomarkers for the early detection of DN and emphasise their potential role as a therapeutic target.

Mini-review: emerging roles of microRNAs in the pathophysiology of renal diseases

MicroRNAs (miRNA) are endogenously produced short noncoding regulatory RNAs that can repress gene expression by posttranscriptional mechanisms. They can therefore influence both normal and pathological conditions in diverse biological systems. Several miRNAs have been detected in kidneys, where they have been found to be crucial for renal development and normal physiological functions as well as significant contributors to the pathogenesis of renal disorders such as diabetic nephropathy, acute kidney injury, lupus nephritis, polycystic kidney disease, and others, due to their effects on key genes involved in these disease processes. miRNAs have also emerged as novel biomarkers in these renal disorders. Due to increasing evidence of their actions in various kidney segments, in this mini-review we discuss the functional significance of altered miRNA expression during the development of renal pathologies and highlight emerging miRNA-based therapeutics and diagnostic strategies for early detection and treatment of kidney diseases.

Integrative Biology of Diabetic Kidney Disease

BACKGROUND

The leading cause of ESRD in the U.S. is diabetic kidney disease (DKD). Despite significant efforts to improve outcomes in DKD, the impact on disease progression has been disappointing. This has prompted clinicians and researchers to search for alternative approaches to identify persons at risk, and to search for more effective therapies to halt progression of DKD. Identification of novel therapies is critically dependent on a more comprehensive understanding of the pathophysiology of DKD, specifically at the molecular level. A more expansive and exploratory view of DKD is needed to complement more traditional research approaches that have focused on single molecules.

SUMMARY

In recent years, sophisticated research methodologies have emerged within systems biology that should allow for a more comprehensive disease definition of DKD. Systems biology provides an inter-disciplinary approach to describe complex interactions within biological systems including how these interactions influence systems' functions and behaviors. Computational modeling of large, system-wide, quantitative data sets is used to generate molecular interaction pathways, such as metabolic and cell signaling networks.

KEY MESSAGES

Importantly, interpretation of data generated by systems biology tools requires integration with enhanced clinical research data and validation using model systems. Such an integrative biological approach has already generated novel insights into pathways and molecules involved in DKD. In this review, we highlight recent examples of how combining systems biology with traditional clinical and model research efforts results in an integrative biology approach that has significantly added to the understanding of the complex pathophysiology of DKD.

MicroRNAs in diabetic nephropathy: functions, biomarkers, and therapeutic targets

MicroRNAs (miRNAs) are short noncoding RNAs that regulate gene expression by posttranscriptional and epigenetic mechanisms and thereby affect many cellular processes and disease states. Over 2,000 human mature miRNAs have been identified, and at least 60% of all human protein-coding genes are known to be regulated by miRNAs. MicroRNA biogenesis involves classical transcription regulation and processing by key ribonucleases, as well as other protein factors and epigenetic mechanisms. Diabetic nephropathy (DN), a severe microvascular complication frequently associated with diabetes mellitus, is a major cause of renal failure. Although several mechanisms of regulation of key renal genes implicated in DN pathogenesis have been identified, a greater understanding is needed to develop better treatment modalities. Recent studies show that miRNAs induced in renal cells in vivo and in vitro under diabetic conditions can promote the accumulation of extracellular matrix proteins related to fibrosis and glomerular dysfunction. In this review, we highlight the significance of the expression of miRNAs in various stages of DN and emerging approaches to exploit them as biomarkers for early detection or novel therapeutic targets to prevent progression of DN.

Circulating TGF-β1-Regulated miRNAs and the Risk of Rapid Progression to ESRD in Type 1 Diabetes

We investigated whether circulating TGF-β1-regulated miRNAs detectable in plasma are associated with the risk of rapid progression to end-stage renal disease (ESRD) in a cohort of proteinuric patients with type 1 diabetes (T1D) and normal eGFR. Plasma specimens obtained at entry to the study were examined in two prospective subgroups that were followed for 7-20 years (rapid progressors and nonprogressors), as well as a reference panel of normoalbuminuric T1D patients. Of the five miRNAs examined in this study, let-7c-5p and miR-29a-3p were significantly associated with protection against rapid progression and let-7b-5p and miR-21-5p were significantly associated with the increased risk of ESRD. In logistic analysis, controlling for HbA1c and other covariates, let-7c-5p and miR-29a-3p were associated with more than a 50% reduction in the risk of rapid progression (P ≤ 0.001), while let-7b-5p and miR-21-5p were associated with a >2.5-fold increase in the risk of ESRD (P ≤ 0.005). This study is the first prospective study to demonstrate that circulating TGF-β1-regulated miRNAs are deregulated early in T1D patients who are at risk for rapid progression to ESRD.

Diabetic nephropathy - complications and treatment

Diabetic nephropathy is a significant cause of chronic kidney disease and end-stage renal failure globally. Much research has been conducted in both basic science and clinical therapeutics, which has enhanced understanding of the pathophysiology of diabetic nephropathy and expanded the potential therapies available. This review will examine the current concepts of diabetic nephropathy management in the context of some of the basic science and pathophysiology aspects relevant to the approaches taken in novel, investigative treatment strategies.

The Role of MicroRNAs in Diabetic Complications-Special Emphasis on Wound Healing

Overweight and obesity are major problems in today’s society, driving the prevalence of diabetes and its related complications. It is important to understand the molecular mechanisms underlying the chronic complications in diabetes in order to develop better therapeutic approaches for these conditions. Some of the most important complications include macrovascular abnormalities, e.g., heart disease and atherosclerosis, and microvascular abnormalities, e.g., retinopathy, nephropathy and neuropathy, in particular diabetic foot ulceration. The highly conserved endogenous small non-coding RNA molecules, the micro RNAs (miRNAs) have in recent years been found to be involved in a number of biological processes, including the pathogenesis of disease. Their main function is to regulate post-transcriptional gene expression by binding to their target messenger RNAs (mRNAs), leading to mRNA degradation, suppression of translation or even gene activation. These molecules are promising therapeutic targets and demonstrate great potential as diagnostic biomarkers for disease. This review aims to describe the most recent findings regarding the important roles of miRNAs in diabetes and its complications, with special attention given to the different phases of diabetic wound healing.

Diabetic nephropathy--emerging epigenetic mechanisms

Diabetic nephropathy (DN), a severe microvascular complication frequently associated with both type 1 and type 2 diabetes mellitus, is a leading cause of renal failure. The condition can also lead to accelerated cardiovascular disease and macrovascular complications. Currently available therapies have not been fully efficacious in the treatment of DN, suggesting that further understanding of the molecular mechanisms underlying the pathogenesis of DN is necessary for the improved management of this disease. Although key signal transduction and gene regulation mechanisms have been identified, especially those related to the effects of hyperglycaemia, transforming growth factor β1 and angiotensin II, progress in functional genomics, high-throughput sequencing technology, epigenetics and systems biology approaches have greatly expanded our knowledge and uncovered new molecular mechanisms and factors involved in DN. These mechanisms include DNA methylation, chromatin histone modifications, novel transcripts and functional noncoding RNAs, such as microRNAs and long noncoding RNAs. In this Review, we discuss the significance of these emerging mechanisms, how they mediate the actions of growth factors to augment the expression of extracellular matrix and inflammatory genes associated with DN and their potential usefulness as diagnostic biomarkers or novel therapeutic targets for DN.

Exosomal miRNAs as potential biomarkers of cardiovascular risk in children

Intercellular interactions are essential for basic cellular activities and errors in either receiving or transferring these signals have shown to cause pathological conditions. These signals are not only regulated by membrane surface molecules but also by soluble secreted proteins, thereby allowing for an exquisite coordination of cell functions. Exosomes are released by cells upon fusion of multivesicular bodies (MVB) with the plasma membrane. Their envelope reflects their cellular origin and their surface and internal contents include important signaling components. Exosomes contain a wide variety of proteins, lipids, RNAs, non-transcribed RNAs, miRNAs and small RNAs that are representative to their cellular origin and shuttle from donor cells to recipient cells. The exosome formation cargo content and delivery is of immense biological interest because exosomes are believed to play major roles in various pathological conditions, and therefore provide unique opportunities for biomarker discovery and development of non-invasive diagnostics when examined in biological fluids such as urine and blood plasma. For example, circulating miRNAs in exosomes have been applied as functional biomarkers for diagnosis and outcomes prediction, while synthetic miRNAs in polymer-based nanoparticles are applicable for therapeutics. This review provides insights into the composition and functional properties of exosomes, and focuses on their potential value as diagnostic markers in the context of cardiovascular disease risk estimates in children who suffer from conditions associated with heightened prevalence of adverse cardiovascular disease, namely obesity and sleep-disordered-breathing.