Identification, Confirmation, and Replication of Novel Urinary MicroRNA Biomarkers in Lupus Nephritis and Diabetic Nephropathy

Investigating the value of urinary biomarkers in relation to lupus nephritis histopathology: present insights and future prospects

Lupus nephritis (LN), a leading cause of death in Systemic Lupus Erythematosus (SLE) patients, presents significant diagnostic and prognostic challenges. Although renal pathology offers critical insights regarding the diagnosis, classification, and therapy for LN, its clinical utility is constrained by the invasive nature and limited reproducibility of renal biopsies. Moreover, the continuous monitoring of renal pathological changes through repeated biopsies is impractical. Consequently, there is a growing interest in exploring urine as a non-invasive, easily accessible, and dynamic "liquid biopsy" alternative to guide clinical management. This paper examines novel urinary biomarkers from a renal pathology perspective, encompassing cellular components, cytokines, adhesion molecules, auto-antibodies, soluble leukocyte markers, light chain fragments, proteins, small-molecule peptides, metabolomics, urinary exosomes, and ribonucleic acids. We also discuss the application of combined models comprising multiple biomarkers in assessing lupus activity. These innovative biomarkers and models offer insights into LN disease activity, acute and chronic renal indices, fibrosis, thrombotic microangiopathy, podocyte injury, and other pathological changes, potentially improving the diagnosis, management, and prognosis of LN. These urinary biomarkers or combined models may serve as viable alternatives to traditional renal pathology, potentially revolutionizing the method for future LN diagnosis and observation.

MicroRNA-630: A promising avenue for alleviating inflammation in diabetic kidney disease

Diabetic kidney disease (DKD) is one of the complications of diabetes, affecting millions of people worldwide. The relentless progression of this condition can lead to kidney failure, requiring life-altering interventions such as dialysis or transplants. Accumulating evidence suggests that immunologic and inflammatory elements play an important role in initiating and perpetuating the damage inflicted on renal tissues, exacerbating the decline in organ function. Toll-like receptors (TLRs) are a family of receptors that play a role in the activation of the innate immune system by the recognition of pathogen-associated molecular patterns. Recent data from in vitro and in vivo studies have highlighted the critical role of TLRs, mainly TLR2 and TLR4, in the pathogenesis of DKD. In the diabetic milieu, these TLRs recognize diabetic-associated molecular signals, triggering a proinflammatory cascade that initiates and perpetuates inflammation and fibrogenesis in the diabetic kidney. Emerging non-traditional strategies targeting TLR signaling with potential therapeutic implications in DKD have been pro-posed. One of these approaches is the use of microRNAs, small non-coding RNAs that can regulate gene expression. This editorial comments on the results of this approach carried out in a rat model of diabetes by Wu et al, published in this issue of the World Journal of Diabetes. The results of the experimental study by Wu et al shows that microRNA-630 decreased levels compared to non-diabetic rats. Additionally, microRNA-630 exerted anti-inflammatory effects in the kidneys of diabetic rats through the modulation of TLR4. These findings indicate that the microRNA-630/TLR4 axis might represent a pathological mechanism of DKD and a potential therapeutic target capable of curbing the destructive inflammation characteristic of DKD.

LncRNA SNHG14 silencing attenuates the progression of diabetic nephropathy via the miR-30e-5p/SOX4 axis

BACKGROUND

Diabetic nephropathy (DN) is a diabetic complication. LncRNAs are reported to participate in the pathophysiology of DN. Here, the function and mechanism of lncRNA small nucleolar RNA host gene 14 (SNHG14) in DN were explored.

METHODS

Streptozotocin (STZ)-induced DN mouse models and high glucose (HG)-treated human mesangial cells (MCs) were used to detect SNHG14 expression. SNHG14 silencing plasmids were applied to examine the function of SNHG14 on proliferation and fibrosis in HG-treated MCs. Potential targets of SNHG14 were predicted using bioinformatics tools and verified by luciferase reporter, RNA pulldown, and northern blotting assays. The functional role of SNHG14 in DN in vivo was detected by injection with adenoviral vector carrying sh-SNHG14 into DN mice. Serum creatinine, blood urea nitrogen, blood glucose, 24-h proteinuria, relative kidney weight, and renal pathological changes were examined in DN mice.

RESULTS

SNHG14 expression was elevated in the kidneys of DN mice and HG-treated MCs. SNHG14 silencing inhibited proliferation and fibrosis of HG-stimulated MCs. SNHG14 bound to miR-30e-5p to upregulate SOX4 expression. In rescue assays, SOX4 elevation diminished the effects of SNHG14 silencing in HG-treated MCs, and SOX4 silencing reversed the effects of SNHG14 overexpression. In in vivo studies, SNHG14 downregulation significantly ameliorated renal injuries and renal interstitial fibrosis in DN mice.

CONCLUSIONS

SNHG14 silencing attenuates kidney injury in DN mice and reduces proliferation and fibrotic phenotype of HG-stimulated MCs via the miR-30e-5p/SOX4 axis.

A Systematic Review and Meta-Analysis of microRNA Profiling Studies in Chronic Kidney Diseases

Chronic kidney disease (CKD) represents an increasing health burden. Evidence suggests the importance of miRNA in diagnosing CKD, yet the reports are inconsistent. This study aimed to determine novel miRNA biomarkers and potential therapeutic targets from hypothesis-free miRNA profiling studies in human and murine CKDs. Comprehensive literature searches were conducted on five databases. Subgroup analyses of kidney diseases, sample types, disease stages, and species were conducted. A total of 38 human and 12 murine eligible studies were analyzed using Robust Rank Aggregation (RRA) and vote-counting analyses. Gene set enrichment analyses of miRNA signatures in each kidney disease were conducted using DIANA-miRPath v4.0 and MIENTURNET. As a result, top target genes, Gene Ontology terms, the interaction network between miRNA and target genes, and molecular pathways in each kidney disease were identified. According to vote-counting analysis, 145 miRNAs were dysregulated in human kidney diseases, and 32 were dysregulated in murine CKD models. By RRA, miR-26a-5p was significantly reduced in the kidney tissue of Lupus nephritis (LN), while miR-107 was decreased in LN patients' blood samples. In both species, epithelial-mesenchymal transition, Notch, mTOR signaling, apoptosis, G2/M checkpoint, and hypoxia were the most enriched pathways. These miRNA signatures and their target genes must be validated in large patient cohort studies.

The Functional Role of microRNAs and mRNAs in Diabetic Kidney Disease: A Review

Diabetes is a group of diseases marked by poor control of blood glucose levels. Diabetes mellitus (DM) occurs when pancreatic cells fail to make insulin, which is required to keep blood glucose levels stable, disorders, and so on. High glucose levels in the blood induce diabetic effects, which can cause catastrophic damage to bodily organs such as the eyes and lower extremities. Diabetes is classified into many forms, one of which is controlled by hyperglycemia or Diabetic Kidney Disease (DKD), and another that is not controlled by hyperglycemia (nondiabetic kidney disease or NDKD) and is caused by other factors such as hypertension, hereditary. DKD is associated with diabetic nephropathy (DN), a leading cause of chronic kidney disease (CKD) and end-stage renal failure. The disease is characterized by glomerular basement membrane thickening, glomerular sclerosis, and mesangial expansion, resulting in a progressive decrease in glomerular filtration rate, glomerular hypertension, and renal failure or nephrotic syndrome. It is also represented by some microvascular complications such as nerve ischemia produced by intracellular metabolic changes, microvascular illness, and the direct impact of excessive blood glucose on neuronal activity. Therefore, DKD-induced nephrotic failure is worse than NDKD. MicroRNAs (miRNAs) are important in the development and progression of several diseases, including diabetic kidney disease (DKD). These dysregulated miRNAs can impact various cellular processes, including inflammation, fibrosis, oxidative stress, and apoptosis, all of which are implicated during DKD. MiRNAs can alter the course of DKD by targeting several essential mechanisms. Understanding the miRNAs implicated in DKD and their involvement in disease development might lead to identifying possible therapeutic targets for DKD prevention and therapy. Therefore, this review focuses specifically on DKD-associated DN, as well as how in-silico approaches may aid in improving the management of the disease.

Long non‑coding RNA L13Rik promotes high glucose-induced mesangial cell hypertrophy and matrix protein expression by regulating miR-2861/CDKN1B axis

Background

Diabetic nephropathy (DN) is a frequent microvascular complication of diabetes. Glomerular mesangial cell (MC) hypertrophy occurs at the initial phase of DN and plays a critical role in the pathogenesis of DN. Given the role of long non coding RNA (lncRNA) in regulating MC hypertrophy and extracellular matrix (ECM) accumulation, our aim was to identify functional lncRNAs during MC hypertrophy.

Methods

Here, an lncRNA, C920021L13Rik (L13Rik for short), was identified to be up-regulated in DN progression. The expression of L13Rik in DN patients and diabetic mice was assessed using quantitative real-time PCR (qRT-PCR), and the function of L13Rik in regulating HG-induced MC hypertrophy and ECM accumulation was assessed through flow cytometry and western blotting analysis.

Results

The L13Rik levels were significantly increased while the miR-2861 levels were decreased in the peripheral blood of DN patients, the renal tissues of diabetic mice, and HG-treated MCs. Functionally, both L13Rik depletion and miR-2861 overexpression effectively reduced HG-induced cell hypertrophy and ECM accumulation. Mechanistically, L13Rik functioned as a competing endogenous RNA (ceRNA) to sponge miR-2861, resulting in the de-repression of cyclin-dependent kinase inhibitor 1B (CDKN1B), a gene known to regulate cell cycle and MC hypertrophy.

Conclusions

Collectively, the current results demonstrate that up-regulated L13Rik is correlated with DN and may be a hopeful therapeutic target for DN.

Systemic lupus erythematosus: From non-coding RNAs to exosomal non-coding RNAs

Systemic lupus erythematosus (SLE), as an immunological illness, frequently impacts young females. Both vulnerabilities to SLE and the course of the illness's clinical symptoms have been demonstrated to be affected by individual differences in non-coding RNA expression. Many non-coding RNAs (ncRNAs) are out of whack in patients with SLE. Because of the dysregulation of several ncRNAs in peripheral blood of patients suffering from SLE, these ncRNAs to be showed valuable as biomarkers for medication response, diagnosis, and activity. NcRNAs have also been demonstrated to influence immune cell activity and apoptosis. Altogether, these facts highlight the need of investigating the roles of both families of ncRNAs in the progress of SLE. Being aware of the significance of these transcripts perhaps elucidates the molecular pathogenesis of SLE and could open up promising avenues to create tailored treatments during this condition. In this review we summarized various non-coding RNAs and Exosomal non-coding RNAs in SLE.

Development and validation of urinary exosomal microRNA biomarkers for the diagnosis of acute rejection in kidney transplant recipients

Introduction

Acute rejection (AR) continues to be a significant obstacle for short- and long-term graft survival in kidney transplant recipients. Herein, we aimed to examine urinary exosomal microRNAs with the objective of identifying novel biomarkers of AR.

Materials and methods

Candidate microRNAs were selected using NanoString-based urinary exosomal microRNA profiling, meta-analysis of web-based, public microRNA database, and literature review. The expression levels of these selected microRNAs were measured in the urinary exosomes of 108 recipients of the discovery cohort using quantitative real-time polymerase chain reaction (qPCR). Based on the differential microRNA expressions, AR signatures were generated, and their diagnostic powers were determined by assessing the urinary exosomes of 260 recipients in an independent validation cohort.

Results

We identified 29 urinary exosomal microRNAs as candidate biomarkers of AR, of which 7 microRNAs were differentially expressed in recipients with AR, as confirmed by qPCR analysis. A three-microRNA AR signature, composed of hsa-miR-21-5p, hsa-miR-31-5p, and hsa-miR-4532, could discriminate recipients with AR from those maintaining stable graft function (area under the curve [AUC] = 0.85). This signature exhibited a fair discriminative power in the identification of AR in the validation cohort (AUC = 0.77).

Conclusion

We have successfully demonstrated that urinary exosomal microRNA signatures may form potential biomarkers for the diagnosis of AR in kidney transplantation recipients.

Dysregulated MicroRNAs in the Pathogenesis of Systemic Lupus Erythematosus: A Comprehensive Review

Systemic lupus erythematosus is a chronic autoimmune disease of which clinical presentation is vastly heterogeneous, ranging from mild skin rashes to severe renal diseases. Treatment goal of this illness is to minimize disease activity and prevent further organ damage. In recent years, much research has been done on the epigenetic aspects of SLE pathogenesis, for among the various factors known to contribute to the pathogenic process, epigenetic factors, especially microRNAs, bear the most therapeutic potential that can be altered unlike congenital genetic factors. This article reviews and updates what has been discovered so far about the pathogenesis of lupus, while focusing on the dysregulation of microRNAs in lupus patients in comparison to healthy controls along with the potentially pathogenic roles of the microRNAs commonly reported to be either upregulated or downregulated. Furthermore, this review includes microRNAs of which results are controversial, suggesting possible explanations for such discrepancies and directions for future research. Moreover, we aimed to emphasize the point that had been overlooked so far in studies regarding microRNA expression levels; that is, which specimen was used to assess the dysregulation of microRNAs. To our surprise, a vast number of studies have not considered this factor and have analyzed the potential role of microRNAs in general. Despite extensive investigations done on microRNA levels, their significance and potential role remain a mystery, which calls for further studies on this particular subject in regard of which specimen is used for assessment.

Intestinal microbiome diversity of diabetic and non-diabetic kidney disease: Current status and future perspective

A significant portion of the health burden of diabetic kidney disease (DKD) is caused by both type 1 and type 2 diabetes which leads to morbidity and mortality globally. It is one of the most common diabetic complications characterized by loss of renal function with high prevalence, often leading to acute kidney disease (AKD). Inflammation triggered by gut microbiota is commonly associated with the development of DKD. Interactions between the gut microbiota and the host are correlated in maintaining metabolic and inflammatory homeostasis. However, the fundamental processes through which the gut microbiota affects the onset and progression of DKD are mainly unknown. In this narrative review, we summarised the potential role of the gut microbiome, their pathogenicity between diabetic and non-diabetic kidney disease (NDKD), and their impact on host immunity. A well-established association has already been seen between gut microbiota, diabetes and kidney disease. The gut-kidney interrelationship is confirmed by mounting evidence linking gut dysbiosis to DKD, however, it is still unclear what is the real cause of gut dysbiosis, the development of DKD, and its progression. In addition, we also try to distinguish novel biomarkers for early detection of DKD and the possible therapies that can be used to regulate the gut microbiota and improve the host immune response. This early detection and new therapies will help clinicians for better management of the disease and help improve patient outcomes.

Candidate MicroRNA Biomarkers in Lupus Nephritis: A Meta-analysis of Profiling Studies in Kidney, Blood and Urine Samples

CONTEXT

Lupus nephritis (LN) is a kidney disease caused by systemic lupus erythematosus in which kidneys are attacked by the immune system. So far, various investigations have reported altered miRNA expression profiles in LN patients and different miRNAs have been introduced as biomarkers and/or therapeutic targets in LN. The aim of this study was to introduce a consensus panel of potential miRNA biomarkers by performing a meta-analysis of miRNA profiles in the LN patients.

MATERIALS AND METHODS

A comprehensive literature review approach was performed to find LN-related miRNA expression profiles in renal tissues, blood, and urine samples. After selecting the eligible studies and performing the data extraction, meta-analysis was done based on the vote-counting rank strategy as well as meta-analysis of p-values. The meta-miRNAs and their related genes were subjected to functional enrichment analyses and network construction.

RESULTS

The results of the meta-analysis of 41 studies were three lists of consensus miRNAs with altered expression profiles in the various tissue samples of LN patients (meta-analysis of p-values < 0.05). Of the 13 studies on kidney tissue, the meta-miRNAs were let-7a, miR-198, let-7e, miR-145, and miR-26a. In addition, meta-miRNAs of miR-199a, miR-21, miR-423, miR-1260b, miR-589, miR-150, miR-155, miR-146a, and miR-183 from 21 studies on blood samples, and miR-146a, miR-204, miR-30c, miR-3201, and miR-1273e from 11 studies on urine samples can be considered as non-invasive biomarker panels for LN. Functional enrichment analysis on the meta-miRNA lists confirmed the involvement of their target genes in nephropathy-related signaling pathways.

CONCLUSION

Using a meta-analytical approach, our study proposes three meta-miRNA panels that could be the target of further research to assess their potential as therapeutic targets/biomarkers in LN disease.

MicroRNAs Associated with Chronic Kidney Disease in the General Population and High-Risk Subgroups-A Systematic Review

The potential utility of microRNAs (miRNAs) as diagnostic or prognostic biomarkers, as well as therapeutic targets, for chronic kidney disease (CKD) has been advocated. However, studies evaluating the expression profile of the same miRNA signatures in CKD report contradictory findings. This review aimed to characterize miRNAs associated with CKD and/or measures of kidney function and kidney damage in the general population, and also in high-risk subgroups, including people with hypertension (HTN), diabetes mellitus (DM) and human immunodeficiency virus (HIV) infection. Medline via PubMed, Scopus, Web of Science, and EBSCOhost databases were searched to identify relevant studies published in English or French languages on or before 30 September 2022. A total of 75 studies fulfilled the eligibility criteria: CKD (n = 18), diabetic kidney disease (DKD) (n = 51) and HTN-associated CKD (n = 6), with no study reporting on miRNA profiles in people with HIV-associated nephropathy. In individuals with CKD, miR-126 and miR-223 were consistently downregulated, whilst in DKD, miR-21 and miR-29b were consistently upregulated and miR-30e and let-7a were consistently downregulated in at least three studies. These findings suggest that these miRNAs may be involved in the pathogenesis of CKD and therefore invites further research to explore their clinical utility for CKD prevention and control.

Multi-Scalar Data Integration Links Glomerular Angiopoietin-Tie Signaling Pathway Activation With Progression of Diabetic Kidney Disease

Diabetic kidney disease (DKD) is the leading cause of end-stage kidney disease (ESKD). Prognostic biomarkers reflective of underlying molecular mechanisms are critically needed for effective management of DKD. A three-marker panel was derived from a proteomics analysis of plasma samples by an unbiased machine learning approach from participants (N = 58) in the Clinical Phenotyping and Resource Biobank study. In combination with standard clinical parameters, this panel improved prediction of the composite outcome of ESKD or a 40% decline in glomerular filtration rate. The panel was validated in an independent group (N = 68), who also had kidney transcriptomic profiles. One marker, plasma angiopoietin 2 (ANGPT2), was significantly associated with outcomes in cohorts from the Cardiovascular Health Study (N = 3,183) and the Chinese Cohort Study of Chronic Kidney Disease (N = 210). Glomerular transcriptional angiopoietin/Tie (ANG-TIE) pathway scores, derived from the expression of 154 ANG-TIE signaling mediators, correlated positively with plasma ANGPT2 levels and kidney outcomes. Higher receptor expression in glomeruli and higher ANG-TIE pathway scores in endothelial cells corroborated potential functional effects in the kidney from elevated plasma ANGPT2 levels. Our work suggests that ANGPT2 is a promising prognostic endothelial biomarker with likely functional impact on glomerular pathogenesis in DKD.

Progress in the application of body fluid and tissue level mRNAs-non-coding RNAs for the early diagnosis and prognostic evaluation of systemic lupus erythematosus

The diagnosis and differential classification of systemic lupus erythematosus (SLE) is difficult, especially in patients with early-onset SLE who are susceptible to systemic multi-organ damage and serious complications and have difficulties in individualized treatment. At present, diagnosis is based mainly on clinical manifestations and the detection of serological antinuclear antibodies. The pathogenesis of SLE involves multiple factors, is clinically heterogeneous, and lacks specific biomarkers. Therefore, it is necessary to identify new biomarkers for the diagnosis and subtype classification of SLE. Non-coding RNAs (ncRNAs) are composed of microRNAs, long non-coding RNAs, small nucleolar RNAs, circular RNAs, and transfer RNAs. They play an important role in the occurrence and development of diseases and are used widely in the early diagnosis and prognosis of autoimmune diseases. In this review, we focus on the research progress in the diagnosis and prognostic assessment of SLE using humoral to tissue level ncRNAs.

Comparison of circulating miR-148a and miR-126 with autoantibodies as biomarkers of lupus nephritis in patients with SLE

Lupus nephritis (LN) is the main manifestation of systemic Lupus Erythematosus (SLE). MicroRNAs (miRNAs) and autoantibodies could be suitable candidate biomarkers of LN. This study evaluates the expression of circulating miR-148a and miR-126 along with anti-dsDNA, anti-C1q, and anti-C3b autoantibodies in SLE patients with LN (SLE + LN). 30 women with SLE, 30 women with SLE + LN, and 25 women as healthy controls (HCs) were enrolled in this study. The plasma expression of selected miRNAs was evaluated by real-time PCR. The serum level of anti-dsDNA, C1q, and C3b antibodies was measured by the ELISA. The expression of miR-148a was significantly increased in SLE and SLE+LN groups compared with the control group. No significant difference was found in the expression of miR-126 among the groups. The frequency of autoantibodies was significantly higher in the SLE + LN group than SLE. The Higher levels of circulating miR-148a in the SLE samples compared with the HCs suggest that this miRNA could be a reliable biomarker for SLE patients (with or without LN). Also, autoantibodies against dsDNA, C1q, and, C3 could be used for the prediction of SLE nephritis, independently. However, further studies are needed to confirm these findings.

Clinical application of microRNAs in glomerular diseases

RNA interference (RNAi) occurs in all organisms and modulates most, if not all, biological pathways. It is the process by which non-coding RNAs, including microRNAs (miRs), regulate gene transcription and post-transcriptional processing of messenger RNA (mRNA). A single miR can modulate several genes within a cell, and several miRs can regulate expression of the same gene, adding tiers of complexity to regulation of gene expression. MicroRNAs and other RNAi approaches have been successfully used in vitro and in vivo to selectively manipulate gene transcription, making them pivotal agents for basic science research and candidates for targeted therapeutics. This review will focus on miRs and their potential as biomarkers and novel therapeutics for glomerular disease.

Biomarkers to Monitor Adherence to Gluten-Free Diet by Celiac Disease Patients: Gluten Immunogenic Peptides and Urinary miRNAs

Celiac disease (CD) is a multifactorial autoimmune enteropathy with a prevalence greater than 1% in the pediatric population. The only therapy for CD patients is a strict gluten-free diet (GFD). Gluten-free food contamination by other cereals during packaging and cooking or accidental ingestion of gluten may cause several intestinal and extraintestinal symptoms in CD patients. Therefore, the monitoring of gluten contamination in food and assessing the level of ingested gluten by analytical biomarkers has been of great interest in recent years. To this aim, small gluten immunogenic peptides (GIPs) obtained by the hydrolysis of gluten and present in urine and feces have been studied as biomarkers of gluten intake and to monitor adherence to GFD by CD patients. More recently, the use of circulating, fecal and urinary miRNAs has emerged as a novel diagnostic tool that can be potentially applied to assess adherence to GFD. Moreover, the presence of GIPs and miRNAs in both feces and urine suggests a similar excretion modality and the possibility of using urinary miRNAs, similarly to GIPs, as potential biomarkers of GFD in CD patients.

Long Non-Coding RNAs H19 and HOTAIR Implicated in Intervertebral Disc Degeneration

Objective: Intervertebral disc degeneration (IDD) is the major cause of low back pain. We aimed to identify the key genes for IDD pathogenesis.

Methods: An integrated analysis of microarray datasets of IDD archived in public Gene Expression Omnibus was performed. Bioinformatics analyses including identification of differentially expressed mRNAs/microRNAs/long non-coding RNAs (DEMs/DEMis/DELs), pathway enrichment, and competitive endogenous RNA (ceRNA) network construction were performed to give insights into the potential functions of differentially expressed genes (DEGs, including DEMs, DEMis, and DELs). The diagnostic value of DEMis in distinguishing IDD from normal controls was evaluated through receiver operating characteristic (ROC) analysis.

Results: DEGs were identified in IDD, including H19 and HOTAIR. In the DEMis–DEMs network of IDD, miR-1291, miR-4270, and miR-320b had high connectivity with targeted DEMs. Cell death biological processes and the JAK–STAT pathway were significantly enriched from targeted DEMs. The area under the curve (AUC) of 10 DEMs including miR-1273e, miR-623, miR-518b, and miR-1291 in ROC analysis was more than 0.8, which indicated that those 10 DEMs had diagnostic value in distinguishing IDD from normal individuals.

Conclusions: DELs H19 and HOTAIR were related to IDD pathogenesis. Cell death biological processes and the JAK–STAT pathway might play key roles in IDD development.

The Dynamics and Plasticity of Epigenetics in Diabetic Kidney Disease: Therapeutic Applications Vis-à-Vis

Chronic kidney disease (CKD) refers to the phenomenon of progressive decline in the glomerular filtration rate accompanied by adverse consequences, including fluid retention, electrolyte imbalance, and an increased cardiovascular risk compared to those with normal renal function. The triggers for the irreversible renal function deterioration are multifactorial, and diabetes mellitus serves as a major contributor to the development of CKD, namely diabetic kidney disease (DKD). Recently, epigenetic dysregulation emerged as a pivotal player steering the progression of DKD, partly resulting from hyperglycemia-associated metabolic disturbances, rising oxidative stress, and/or uncontrolled inflammation. In this review, we describe the major epigenetic molecular mechanisms, followed by summarizing current understandings of the epigenetic alterations pertaining to DKD. We highlight the epigenetic regulatory processes involved in several crucial renal cell types: Mesangial cells, podocytes, tubular epithelia, and glomerular endothelial cells. Finally, we highlight epigenetic biomarkers and related therapeutic candidates that hold promising potential for the early detection of DKD and the amelioration of its progression.

MicroRNAs in Lupus Nephritis-Role in Disease Pathogenesis and Clinical Applications

MicroRNAs (miRs) are non-coding small RNAs that act as epigenetic modulators to regulate the protein levels of target mRNAs without modifying the genetic sequences. The role of miRs in the pathogenesis of lupus nephritis (LN) is increasingly recognized and highly complex. Altered levels of different miRs are observed in the blood, urine and kidney tissues of murine LN models and LN patients. Accumulating evidence suggests that these miRs can modulate immune cells and various key inflammatory pathways, and their perturbations contribute to the aberrant immune response in LN. The dysregulation of miRs in different resident renal cells and urinary exosomes can also lead to abnormal renal cell proliferation, inflammation and kidney fibrosis in LN. While miRs may hold promise in various clinical applications in LN patients, there are still many potential limitations and safety concerns for their use. Further studies are worthwhile to examine the clinical utility of miRs in the diagnosis, disease activity monitoring, prognostication and treatment of LN.

Diagnostic value of TWEAK for predicting active lupus nephritis in patients with systemic lupus erythematosus: a systematic review and meta-analysis

Purpose

Accumulative studies showed that tumor necrosis factor (TNF)-like weak inducer of apoptosis (TWEAK) was up-regulated in the blood and urine from patients diagnosed with lupus nephritis (LN) and that it might be used as a novel biomarker for active LN. This meta-analysis aimed to determine the diagnostic value of TWEAK in active LN.

Methods

We searched the Cochrane Library, Embase, PubMed, Springer, Wanfang and CNKI databases for articles published up to 20 August 2020. The diagnostic capacity of TWEAK for active LN was assessed using pooled sensitivity and specificity, positive and negative likelihood ratios (PLR and NLR), diagnostic odds ratio (DOR), and area under the receiver operating characteristic curve (AUC). Quality assessment and publication bias were also evaluated. STATA 11.0 and Meta-Disc 1.4 were used to perform these analyses.

Results

Nine cross-sectional studies were included in this meta-analysis. The overall pooled sensitivity of TWEAK for the diagnosis of active LN was 0.69 (95% CI, 0.63–0.75), and specificity was 0.77 (95% CI, 0.71–0.82). The overall pooled PLR and NLR were 3.31 (95% CI, 2.05–5.35) and 0.38 (95% CI, 0.26–0.55), respectively, with a DOR of 10.89 (95% CI, 6.73–17.63) and AUC (SE) of 0.8276 (0.0289). Deeks’ funnel plot revealed that the publication bias was insignificant in the study (p = .32).

Conclusions

Our results suggest that TWEAK might be a potential biomarker for patients with active LN. Future cross-sectional and longitudinal studies are needed to confirm its diagnostic value, as well as to establish more definite cutoff for active LN.

HNRNPA1-mediated exosomal sorting of miR-483-5p out of renal tubular epithelial cells promotes the progression of diabetic nephropathy-induced renal interstitial fibrosis

Diabetic nephropathy (DN) is a serious complication in type 1 and type 2 diabetes, and renal interstitial fibrosis plays a key role in DN progression. Here, we aimed to probe into the role and potential mechanism of miR-483-5p in DN-induced renal interstitial fibrosis. In this study, we corroborated that miR-483-5p expression was lessened in type 1 and type 2 diabetic mice kidney tissues and high glucose (HG)-stimulated tubular epithelial cells (TECs), and raised in the exosomes derived from renal tissues in type 1 and type 2 diabetic mice. miR-483-5p restrained the expressions of fibrosis-related genes in vitro and renal interstitial fibrosis in vivo. Mechanistically, miR-483-5p bound both TIMP2 and MAPK1, and TIMP2 and MAPK1 were bound up with the regulation of miR-483-5p on renal TECs under HG conditions. Importantly, HNRNPA1-mediated exosomal sorting transported cellular miR-483-5p out of TECs into the urine. Our results expounded that HNRNPA1-mediated exosomal sorting transported cellular miR-483-5p out of TECs into the urine, thus lessening the restraint of cellular miR-483-5p on MAPK1 and TIMP2 mRNAs, and ultimately boosting extracellular matrix deposition and the progression of DN-induced renal interstitial fibrosis.

Antisense oligonucleotide development for the selective modulation of CYP3A5 in renal disease

CYP3A5 is the primary CYP3A subfamily enzyme expressed in the human kidney and its aberrant expression may contribute to a broad spectrum of renal disorders. Pharmacogenetic studies have reported inconsistent linkages between CYP3A5 expression and hypertension, however, most investigators have considered CYP3A5*1 as active and CYP3A5*3 as an inactive allele. Observations of gender specific differences in CYP3A5*3/*3 protein expression suggest additional complexity in gene regulation that may underpin an environmentally responsive role for CYP3A5 in renal function. Reconciliation of the molecular mechanism driving conditional restoration of functional CYP3A5*3 expression from alternatively spliced transcripts, and validation of a morpholino-based approach for selectively suppressing renal CYP3A5 expression, is the focus of this work. Morpholinos targeting a cryptic splice acceptor created by the CYP3A5*3 mutation in intron 3 rescued functional CYP3A5 expression in vitro, and salt-sensitive cellular mechanisms regulating splicing and conditional expression of CYP3A5*3 transcripts are reported. The potential for a G-quadruplex (G4) in intron 3 to mediate restored splicing to exon 4 in CYP3A5*3 transcripts was also investigated. Finally, a proximal tubule microphysiological system (PT-MPS) was used to evaluate the safety profile of morpholinos in proximal tubule epithelial cells, highlighting their potential as a therapeutic platform for the treatment of renal disease.

Aberrant Non-Coding RNA Expression in Patients with Systemic Lupus Erythematosus: Consequences for Immune Dysfunctions and Tissue Damage

Systemic lupus erythematosus (SLE) is a complex systemic autoimmune disease with heterogeneous clinical manifestations. A diverse innate and adaptive immune dysregulation is involved in the immunopathogenesis of SLE. The dysregulation of immune-related cells may derive from the intricate interactions among genetic, epigenetic, environmental, and immunological factors. Of these contributing factors, non-coding RNAs (ncRNAs), including microRNAs (miRNAs, miRs), and long non-coding RNAs (lncRNAs) play critical roles in the post-transcriptional mRNA expression of cytokines, chemokines, and growth factors, which are essential for immune modulation. In the present review, we emphasize the roles of ncRNA expression in the immune-related cells and cell-free plasma, urine, and tissues contributing to the immunopathogenesis and tissue damage in SLE. In addition, the circular RNAs (circRNA) and their post-translational regulation of protein synthesis in SLE are also briefly described. We wish these critical reviews would be useful in the search for biomarkers/biosignatures and novel therapeutic strategies for SLE patients in the future.

Genomics of Human Fibrotic Diseases: Disordered Wound Healing Response

Fibrotic disease, which is implicated in almost half of all deaths worldwide, is the result of an uncontrolled wound healing response to injury in which tissue is replaced by deposition of excess extracellular matrix, leading to fibrosis and loss of organ function. A plethora of genome-wide association studies, microarrays, exome sequencing studies, DNA methylation arrays, next-generation sequencing, and profiling of noncoding RNAs have been performed in patient-derived fibrotic tissue, with the shared goal of utilizing genomics to identify the transcriptional networks and biological pathways underlying the development of fibrotic diseases. In this review, we discuss fibrosing disorders of the skin, liver, kidney, lung, and heart, systematically (1) characterizing the initial acute injury that drives unresolved inflammation, (2) identifying genomic studies that have defined the pathologic gene changes leading to excess matrix deposition and fibrogenesis, and (3) summarizing therapies targeting pro-fibrotic genes and networks identified in the genomic studies. Ultimately, successful bench-to-bedside translation of observations from genomic studies will result in the development of novel anti-fibrotic therapeutics that improve functional quality of life for patients and decrease mortality from fibrotic diseases.

Identification of Cooperative Gene Regulation Among Transcription Factors, LncRNAs, and MicroRNAs in Diabetic Nephropathy Progression

The pathogenesis of diabetic nephropathy (DN) is accompanied by alterations in biological function and signaling pathways regulated through complex molecular mechanisms. A number of regulatory factors, including transcription factors (TFs) and non-coding RNAs (ncRNAs, including lncRNAs and miRNAs), have been implicated in DN; however, it is unclear how the interactions among these regulatory factors contribute to the development of DN pathogenesis. In this study, we developed a network-based analysis to decipher interplays between TFs and ncRNAs regulating progression of DN by combining omics data with regulatory factor-target information. To accomplish this, we identified differential expression programs of mRNAs and miRNAs during early DN (EDN) and established DN. We then uncovered putative interactive connections among miRNA-mRNA, lncRNA-miRNA, and lncRNA-mRNA implicated in transcriptional control. This led to the identification of two lncRNAs (MALAT1 and NEAT1) and the three TFs (NF-κB, NFE2L2, and PPARG) that likely cooperate with a set of miRNAs to modulate EDN and DN target genes. The results highlight how crosstalk among TFs, lncRNAs, and miRNAs regulate the expression of genes both transcriptionally and post-transcriptionally, and our findings provide new insights into the molecular basis and pathogenesis of progressive DN.

Platelet-derived microparticles enhance megakaryocyte differentiation and platelet generation via miR-1915-3p

Thrombosis leads to platelet activation and subsequent degradation; therefore, replenishment of platelets from hematopoietic stem/progenitor cells (HSPCs) is needed to maintain the physiological level of circulating platelets. Platelet-derived microparticles (PMPs) are protein- and RNA-containing vesicles released from activated platelets. We hypothesized that factors carried by PMPs might influence the production of platelets from HSPCs, in a positive feedback fashion. Here we show that, during mouse acute liver injury, the density of megakaryocyte in the bone marrow increases following an increase in circulating PMPs, but without thrombopoietin (TPO) upregulation. In vitro, PMPs are internalized by HSPCs and drive them toward a megakaryocytic fate. Mechanistically, miR-1915-3p, a miRNA highly enriched in PMPs, is transported to target cells and suppresses the expression levels of Rho GTPase family member B, thereby inducing megakaryopoiesis. In addition, direct injection of PMPs into irradiated mice increases the number of megakaryocytes and platelets without affecting TPO levels. In conclusion, our data reveal that PMPs have a role in promoting megakaryocytic differentiation and platelet production.

Platelets derive from megakaryocytes, which differentiate from hematopoietic stem/progenitor cells (HSPCs). Here, Qu et al show that platelet-derived microparticles carrying miR-1915-3p target HSPCs and promote megakaryopoiesis by suppressing RHOB expression levels.

Discovering the signature of a lupus-related microRNA profile in the Gene Expression Omnibus repository

Lupus is one of the most prevalent systemic autoimmune diseases. It is a multifactorial disease in which genetic, epigenetic and environmental factors play significant roles. The pathogenesis of lupus is not yet well understood. However, deregulation of microRNAs (miRNAs) - one of the post-transcriptional regulators of genes - can contribute to the development of autoimmune diseases. Over the last two decades, advances in the profiling of miRNA using microarray have received much attention, and it has been demonstrated that miRNAs play a regulatory role in the pathogenesis of lupus. Therefore, dysregulated miRNAs can be considered as promising diagnostic biomarkers for lupus. This article is an overview of lupus-related miRNA profiling studies and arrays in the Gene Expression Omnibus (GEO) database. The aims of our study were to widen current knowledge of known dysregulated miRNAs as potential biomarkers of SLE and to introduce a bioinformatics approach to using microarray data and finding novel miRNA and gene candidates for further study. We identified hsa-miR-4709-5p, hsa-miR-140, hsa-miR-145, hsa-miR-659, hsa-miR-134, hsa-miR-150, hsa-miR-584, hsa-miR-409 and hsa-miR-152 as potential biomarkers by integrated bioinformatics analysis.

MicroRNAs in Systemic Lupus Erythematosus: a Perspective on the Path from Biological Discoveries to Clinical Practice

PURPOSE OF REVIEW

MicroRNAs (miRNAs) play essential roles in immune abnormalities and organ damage of systemic lupus erythematosus (SLE). Current findings have indicated potential clinical applications of miRNAs for combating SLE. Here, we review recent evidence which support the notions that miRNAs can be novel biomarkers and therapeutic agents for SLE.

RECENT FINDINGS

Following years of the studies of the expression patterns of miRNAs in both peripheral blood cells and body fluids, such as plasma and urine, several miRNAs or miRNA combinations have been associated with disease activity and specific organ damage. In depth analysis reveals complex and multiple roles of certain miRNAs in the pathogenesis of SLE. Manipulating miRNA expression shows in vivo therapeutic effects in lupus mouse models. MiRNAs contribute to the immune disorders and organ damage in SLE. MiRNA based biomarkers and therapies have the potential to be viable options for the treatment of SLE.

Personalized therapy design for systemic lupus erythematosus based on the analysis of protein-protein interaction networks

We analyzed protein expression data for Lupus patients, which have been obtained from publicly available databases. A combination of systems biology and statistical thermodynamics approaches was used to extract topological properties of the associated protein-protein interaction networks for each of the 291 patients whose samples were used to provide the molecular data. We have concluded that among the many proteins that appear to play critical roles in this pathology, most of them are either ribosomal proteins, ubiquitination pathway proteins or heat shock proteins. We propose some of the proteins identified in this study to be considered for drug targeting.

A systematic integrative approach reveals novel microRNAs in diabetic nephropathy

Background:

Despite huge efforts, the underlying molecular mechanisms of diabetic nephropathy (DN) are yet elusive, and holistic views have rarely been generated. Considering the complexity of DN pathogenesis, the integration of datasets from different molecular types to construct a multilayer map of DN can provide a comprehensive insight toward the disease mechanisms and also can generate new knowledge. Here, we have re-analyzed two mRNA microarray datasets related to glomerular and tubulointerstitial compartments of human diabetic kidneys.

Materials and Methods:

The quality of the datasets was confirmed by unsupervised hierarchical clustering and principal component analysis. For each dataset, differentially expressed (DE) genes were identified, and transcription factors (TFs) regulating these genes and kinases phosphorylating the TFs were enriched. Furthermore, microRNAs (miRNAs) targeting the DE genes, TFs, and kinases were detected. Based on the harvested genes for glomeruli and tubulointerstitium, key signaling pathways and biological processes involved in diseases pathogenesis were recognized. In addition, the interaction of different elements in each kidney compartment was depicted in multilayer networks, and topology analysis was performed to identify key nodes. Central miRNAs whose target genes were most likely to be related to DN were selected, and their expressions were quantitatively measured in a streptozotocin-induced DN mouse model.

Results:

Among the examined miRNAs, miR-208a-3p and miR-496a-3p are, for the first time, found to be significantly overexpressed in the cortex of diabetic kidneys compared to controls.

Conclusion:

We predict that miR-208 is involved in oxygen metabolism and regulation of cellular energy balance. Furthermore, miR-496 potentially regulates protein metabolism and ion transport. However, their exact functions remain to be investigated in future studies. Taken together, starting from transcriptomics data, we have generated multilayer interaction networks and introduced novel players in DN.

A novel urinary microRNA biomarker panel for detecting gastric cancer

BACKGROUND

Gastric cancer (GC) is one of the most common causes of cancer deaths worldwide; however, reliable and non-invasive screening methods for GC are not established. Therefore, we conducted this study to develop a biomarker for GC detection, consisting of urinary microRNAs (miRNAs).

METHODS

We matched 306 participants by age and sex [153 pairs consisting of patients with GC and healthy controls (HCs)], then randomly divided them across three groups: (1) the discovery cohort (4 pairs); (2) the training cohort (95 pairs); and (3) the validation cohort (54 pairs).

RESULTS

There were 22 urinary miRNAs with significantly aberrant expressions between the two groups in the discovery cohort. Upon multivariate analysis of the training cohort, urinary expression levels of miR-6807-5p and miR-6856-5p were significantly independent biomarkers for diagnosis of GC, in addition to Helicobacter pylori (H. pylori) status. A diagnostic panel that combined these 2 miRNAs and H. pylori status distinguished between HC and GC samples with an area under the curve (AUC) = 0.736. In the validation cohort, urinary miR-6807-5p and miR-6856-5p showed significantly higher expression levels in the GC group, and the combination biomarker panel of miR-6807-5p, miR-6856-5p, and H. pylori status also showed excellent performance (AUC = 0.885). In addition, this biomarker panel could distinguish between HC and stage I GC patients with an AUC = 0.748. Urinary expression levels of miR-6807-5p and miR-6856-5p significantly decreased to undetectable level after curative resection of GC.

CONCLUSIONS

This novel biomarker panel enables early and non-invasive detection of GC.

MicroRNA‑379‑5p suppresses renal fibrosis by regulating the LIN28/let‑7 axis in diabetic nephropathy

MicroRNAs (miRNAs or miRs) play an important role in pathological processes in diabetic nephropathy (DN). This study aimed to explore whether miR‑379‑5p is associated with renal fibrosis in DN and to elucidate the underlying mechanisms. In vitro experiments indicated that miR‑379‑5p expression was downregulated by high glucose (HG) treatment in mouse mesangial cells (MMCs). Transfection with miR‑379‑5p mimics suppressed the proliferation and the accumulation of extracellular matrix (ECM) components, which were promoted by HG treatment. LIN28B was proven to be a direct target of miR‑379‑5p by luciferase report assay. In addition, the loss of expression of LIN28B, as well as the decrease in cell proliferation and in the accumulation of ECM components, which were induced by the knockdown of LIN28B, were attenuated in the MMCs following transfection with miR‑379‑5p inhibitors. Furthermore, type 2 diabetic db/db mice were used to examine the efficiency of miR‑379‑5p agomir in the alleviation of renal fibrosis. Consistent with the results of the in vitro experiments, miR‑379‑5p agomir suppressed mesangial cell proliferation and the accumulation of ECM components by regulating the LIN28B/let‑7 pathway. Taken together, the findings of this study suggest that miR‑379‑5p is highly involved in renal fibrosis in DN, and that it may be a potential effective therapeutic target for DN.

Nephrotoxicity and Renal Pathophysiology: A Contemporary Perspective

The kidney consists of numerous cell types organized into the nephron, which is the basic functional unit of the kidney. Any stimuli that induce loss of these cells can induce kidney damage and renal failure. The cause of renal failure can be intrinsic or extrinsic. Extrinsic causes include cardiovascular disease, obesity, diabetes, sepsis, and lung and liver failure. Intrinsic causes include glomerular nephritis, polycystic kidney disease, renal fibrosis, tubular cell death, and stones. The kidney plays a prominent role in mediating the toxicity of numerous drugs, environmental pollutants and natural substances. Drugs known to be nephrotoxic include several cancer therapeutics, drugs of abuse, antibiotics, and radiocontrast agents. Environmental pollutants known to target the kidney include cadmium, mercury, arsenic, lead, trichloroethylene, bromate, brominated-flame retardants, diglycolic acid, and ethylene glycol. Natural nephrotoxicants include aristolochic acids and mycotoxins such as ochratoxin, fumonisin B1, and citrinin. There are several common characteristics between mechanisms of renal failure induced by nephrotoxicants and extrinsic causes. This common ground exists primarily due to similarities in the molecular mechanisms mediating renal cell death. This review summarizes the current state of the field of nephrotoxicity. It emphasizes integrating our understanding of nephrotoxicity with pathological-induced renal failure. Such approaches are needed to address major questions in the field, which include the diagnosis, prognosis and treatment of both acute and chronic renal failure, and the progression of acute kidney injury to chronic kidney disease.

Preclinical and early systemic lupus erythematosus

The challenge of early diagnosis and treatment is a timely issue in the management of systemic lupus erythematosus (SLE), as autoimmunity starts earlier than its clinical manifestations. Hence, growing efforts for stratification of patients according to the individual risk of developing specific clinical manifestations and/or predicting a better response to a given treatment have led to the proposal of several biomarkers, which require validation for use in clinical practice. In this viewpoint, we aim at distinguishing and discussing the features and the approach to asymptomatic immunological abnormalities potentially heralding the development of SLE, defined as preclinical lupus, and clinical manifestations consistent with SLE not yet fulfilling classification criteria, defined as early lupus. In case of preclinical SLE, careful surveillance using available screening tools is paramount, while patients with early lupus deserve an appropriate and timely diagnosis and, consequently, a proper treatment including hydroxychloroquine as the anchor drug.

MiR-30e-5p and MiR-15a-5p Expressions in Plasma and Urine of Type 1 Diabetic Patients With Diabetic Kidney Disease

Introduction

Diabetic kidney disease (DKD) is a common microvascular complication that affects 40% of patients with diabetes mellitus (DM). Emerging evidence suggests a role for several microRNAs (miRNAs) in the development of DKD. In this context, miR-15a-5p and miR-30e-5p have been shown to regulate the expression of the uncoupling protein 2 (UCP2), a mitochondrial protein that decreases reactive oxygen species (ROS) formation by the mitochondria. Since ROS overproduction is a key contributor to the pathogenesis of DKD, dysregulation of these two miRNAs could be involved in DKD pathogenesis. Thus, the aim of this study was to compare the expressions of miR-15a-5p and miR-30e-5p in type 1 DM (T1DM) patients with DKD (cases) and without this complication (controls), and to perform bioinformatics analyses to investigate their putative targets and biological pathways under their regulation.

Methods

MiR-15a-5p and miR-30e-5p expressions were analyzed in plasma and urine of 17 T1DM controls and 23 DKD cases (12 with moderate DKD and 11 with severe DKD) using qPCR. Bioinformatics analyses were performed in Cytoscape software.

Results

MiR-30e-5p expression was downregulated in plasma of patients with moderate and severe DKD compared to T1DM controls. Moreover, this miRNA was also downregulated in urine of patients with severe DKD compared to the other groups. No difference was found in miR-15a-5p expression between groups. Bioinformatics analyses indicated that miR-30e-5p and miR-15a-5p regulate various genes that participate in pathways related to angiogenesis, apoptosis, cell differentiation, oxidative stress, and hypoxia.

Conclusion

MiR-30e-5p seems to be downregulated in plasma and urine of patients with DKD.

MicroRNA as novel biomarkers and therapeutic targets in diabetic kidney disease: An update

Diabetic kidney disease (DKD) is a life-limiting condition characterized by progressive and irreversible loss of renal function. Currently, the estimated glomerular filtration rate (eGFR) and albuminuria are used as key markers to define DKD. However, they may not accurately indicate the degree of renal dysfunction and injury. Current therapeutic approaches for DKD, including attainment of blood pressure goals, optimal control of blood glucose and lipid levels, and the use of agents to block the renin-angiotensin-aldosterone system (RAAS) can only slow the progression of DKD. Hence, early diagnosis and innovative strategies are needed to both prevent and treat DKD. In recent years, a novel class of noncoding RNA, microRNAs (miRNAs) are reported to be involved in all biological processes, including cellular proliferation, apoptosis, and differentiation. miRNAs are small noncoding RNAs that regulate gene expression by posttranscriptional and epigenetic mechanisms. They are found to be in virtually all body fluids and used successfully as biomarkers for various diseases. Urinary miRNAs correlate with clinical and histologic parameters in DKD and differential urinary miRNA expression patterns have been reported. Kidney fibrosis is the common end stage of various CKD including DKD. Transforming growth factor-β(TGF-β) is regarded as the master regulator of kidney fibrosis, which is likely at least in part through regulating miRNA expression. miRNA are widely involved in the progression of DKD via many molecular mechanisms. In this review, the involvement of miRNA in fibrosis, inflammation, hypertrophy, autophagy, endoplasmic reticulum (ER) stress, oxidative stress, insulin resistance, and podocyte injury will be discussed, as these mechanisms are believed to offer new therapeutic targets that can be exploited to develop important treatments for DKD over the next decade.

miR-1915-3p inhibits Bcl-2 expression in the development of gastric cancer

Many gene expressions changed during the development of gastric cancer, and non-coding RNAs including microRNAs (miRNAs) have been found to regulate cancer progression by participating in the process of tumor cell growth, migration, invasion and apoptosis. Our previous study has identified 29 miRNAs that are highly expressed in gastric cancer stem cells. One of these miRNAs, miR-1915-3p, has shown great potential as a diagnostic and prognostic biomarker for the cancers in liver, colon and thyroid, as well as in immune and kidney diseases. Herein, we found that miR-1915-3p exhibited low expression level in differentiated gastric cancer cell lines and gastric cancer tissues. It was found that the miR-1915-3p inhibited the growth of gastric cancer cells and thus promoted cell apoptosis. We discovered that the expressions of miR-1915-3p were significantly correlated to the lymph node metastasis and overall survival of patients with gastric cancer. Further study showed that there was a negative correlation between miR-1915-3p and Bcl-2 (B cell lymphoma/leukemia-2) expression, suggesting that Bcl-2 was a target gene of miR-1915-3p. Hence, miR-1915-3p possibly contributes to the development and progression of gastric cancer by inhibiting the anti-apoptotic protein Bcl-2. The finding provides a potential therapeutic strategy for gastric cancer.

Non-Coding RNAs as New Therapeutic Targets in the Context of Renal Fibrosis

Fibrosis, or tissue scarring, is defined as the excessive, persistent and destructive accumulation of extracellular matrix components in response to chronic tissue injury. Renal fibrosis represents the final stage of most chronic kidney diseases and contributes to the progressive and irreversible decline in kidney function. Limited therapeutic options are available and the molecular mechanisms governing the renal fibrosis process are complex and remain poorly understood. Recently, the role of non-coding RNAs, and in particular microRNAs (miRNAs), has been described in kidney fibrosis. Seminal studies have highlighted their potential importance as new therapeutic targets and innovative diagnostic and/or prognostic biomarkers. This review will summarize recent scientific advances and will discuss potential clinical applications as well as future research directions.

MicroRNA-204-5p suppresses IL6-mediated inflammatory response and chemokine generation in HK-2 renal tubular epithelial cells by targeting IL6R

During the pathogenetic process of varied kidney diseases, renal tubules are the major sites in response to detrimental insults, including pro-inflammatory stimuli. MicroRNA-204-5p (miR-204-5p) can be detected in the renal tubular epithelial cells in the normal kidney; its expression, however, is downregulated in the kidney with pathological changes. This study aimed to investigate the role of miR-204-5p in interleukin 6 (IL6) mediated inflammatory response and chemokine production in HK-2 renal tubular cells. In HK-2 cells, the expression of miR-204-5p was downregulated in response to exogenous pro-inflammatory stimulus, tumor necrosis factor α (TNFα), or IL1β, while that of IL6 receptor α (IL6R) was upregulated. Dual-luciferase results confirmed that miRNA-204-5p directly targeted IL6R. In addition to suppressing IL6R expression, miRNA-204-5p agomir also inhibited the phosphorylation of signal transducer and activator of transcription 3 (STAT3) in HK-2 cells exposed to exogenous IL6. Further, miRNA-204-5p suppressed the overproduction of pro-inflammatory mediators (cyclooxygenase 2 and prostaglandin E2) and chemokines (C–C motif chemokine ligand 2 and C–X–C motif chemokine ligand 8). The anti-inflammatory effects of miRNA-204-5p were attenuated when IL6R was reexpressed in HK-2 cells. Collectively, our study reveals that miR-204-5p inhibits the inflammation and chemokine generation in renal tubular epithelial cells by modulating the IL6/IL6R axis.

MIR4532 gene variant rs60432575 influences the expression of KCNJ11 and the sulfonylureas-stimulated insulin secretion

PURPOSE

Diabetes mellitus is a major chronic disease and causes over one million deaths. KCNJ11 genetic polymorphisms influence the response of first-line oral antidiabetic agent sulfonylureas. Hsa-miR-4532 correlates with diabetic nephropathy and has a high abundance in urine. MIR4532 rs60452575 G>A variant changes the mature sequence of hsa-miR-4532. We studied whether the genetic polymorphisms of MIR4532 rs60452575 would influence KCNJ11 expression and sulfonylurea-stimulated insulin secretion or not.

METHODS

To estimate the influence that rs60452575 G>A variant has on the interaction of hsa-miR-4532 and KCNJ11, we constructed a pmirGLO vector containing 3' UTR of KCNJ11 and co-transfected it with wild-type and mutant hsa-miR-4532 mimics into HEK293 cells; and we overexpressed wild-type and mutant hsa-miR-4532 mimics into HEK293 cells and MIN6 cells to access its effects on KCNJ11 expression and response of sulfonylureas.

RESULTS

MIR4532 rs60452575 G>A variant appeared to disrupt the repression of KCNJ11 expression in both cell lines, and reduce the sulfonylurea-stimulated insulin secretion by breaking the binding of the hsa-miR-4532 to 3' UTR of KCNJ11 in MIN6 cells.

CONCLUSIONS

Our study indicates that MIR4532 rs60452575 variant influences KCNJ11 expression and sulfonylurea response. It might be a potential predictive factor of sulfonylureas therapy.

Epigenetic Modification Mechanisms Involved in Inflammation and Fibrosis in Renal Pathology

The growing incidence of obesity, hypertension, and diabetes, coupled with the aging of the population, is increasing the prevalence of renal diseases in our society. Chronic kidney disease (CKD) is characterized by persistent inflammation, fibrosis, and loss of renal function leading to end-stage renal disease. Nowadays, CKD treatment has limited effectiveness underscoring the importance of the development of innovative therapeutic options. Recent studies have identified how epigenetic modifications participate in the susceptibility to CKD and have explained how the environment interacts with the renal cell epigenome to contribute to renal damage. Epigenetic mechanisms regulate critical processes involved in gene regulation and downstream cellular responses. The most relevant epigenetic modifications that play a critical role in renal damage include DNA methylation, histone modifications, and changes in miRNA levels. Importantly, these epigenetic modifications are reversible and, therefore, a source of potential therapeutic targets. Here, we will explain how epigenetic mechanisms may regulate essential processes involved in renal pathology and highlight some possible epigenetic therapeutic strategies for CKD treatment.

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.

Precision medicine in lupus nephritis: can biomarkers get us there?

Patients with systemic lupus erythematosus frequently develop lupus nephritis (LN), a condition that can lead to end-stage kidney disease. Multiple serum and urine biomarkers for LN have been proposed in recent years, yet none have become incorporated into clinical use. The majority of studies have been single center with significant variability in cohorts, assays, and sample storage, leading to inconclusive results. It has become clear that no single biomarker is likely to be sufficient to diagnose LN, identify flares, and define the response to therapy and prognosis. A more likely scenario is a panel of urine, serum, tissue, and genetic biomarkers. In this review, we summarize traditional and novel biomarkers and discuss how they may be utilized in order to bring precision medicine to clinical practice in LN.

Genomic approaches in the search for molecular biomarkers in chronic kidney disease

BACKGROUND

Chronic kidney disease (CKD) is recognised as a global public health problem, more prevalent in older persons and associated with multiple co-morbidities. Diabetes mellitus and hypertension are common aetiologies for CKD, but IgA glomerulonephritis, membranous glomerulonephritis, lupus nephritis and autosomal dominant polycystic kidney disease are also common causes of CKD.

MAIN BODY

Conventional biomarkers for CKD involving the use of estimated glomerular filtration rate (eGFR) derived from four variables (serum creatinine, age, gender and ethnicity) are recommended by clinical guidelines for the evaluation, classification, and stratification of CKD. However, these clinical biomarkers present some limitations, especially for early stages of CKD, elderly individuals, extreme body mass index values (serum creatinine), or are influenced by inflammation, steroid treatment and thyroid dysfunction (serum cystatin C). There is therefore a need to identify additional non-invasive biomarkers that are useful in clinical practice to help improve CKD diagnosis, inform prognosis and guide therapeutic management.

CONCLUSION

CKD is a multifactorial disease with associated genetic and environmental risk factors. Hence, many studies have employed genetic, epigenetic and transcriptomic approaches to identify biomarkers for kidney disease. In this review, we have summarised the most important studies in humans investigating genomic biomarkers for CKD in the last decade. Several genes, including UMOD, SHROOM3 and ELMO1 have been strongly associated with renal diseases, and some of their traits, such as eGFR and serum creatinine. The role of epigenetic and transcriptomic biomarkers in CKD and related diseases is still unclear. The combination of multiple biomarkers into classifiers, including genomic, and/or epigenomic, may give a more complete picture of kidney diseases.

The regulatory role of microRNAs in angiogenesis-related diseases

MicroRNAs (miRNAs) are small non-coding RNAs that regulate gene expression at a post-transcriptional level via either the degradation or translational repression of a target mRNA. They play an irreplaceable role in angiogenesis by regulating the proliferation, differentiation, apoptosis, migration and tube formation of angiogenesis-related cells, which are indispensable for multitudinous physiological and pathological processes, especially for the occurrence and development of vascular diseases. Imbalance between the regulation of miRNAs and angiogenesis may cause many diseases such as cancer, cardiovascular disease, aneurysm, Kawasaki disease, aortic dissection, phlebothrombosis and diabetic microvascular complication. Therefore, it is important to explore the essential role of miRNAs in angiogenesis, which might help to uncover new and effective therapeutic strategies for vascular diseases. This review focuses on the interactions between miRNAs and angiogenesis, and miRNA-based biomarkers in the diagnosis, treatment and prognosis of angiogenesis-related diseases, providing an update on the understanding of the clinical value of miRNAs in targeting angiogenesis.

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.

Utility of Serum miR-122, Liver Enzymes, and Hepatic Histopathology in Response to Hepatotoxicants in Sprague-Dawley Rats

More than 80,000 chemicals are in commercial use worldwide. Hepatic metabolism to toxic intermediates is often a key mechanism leading to tissue damage and organ dysfunction. Effective treatment requires prompt detection of hepatotoxicity, ideally with rapid, minimally invasive diagnostic assays. In this study, archetypal histologic features of chemically induced hepatic injury were compared with clinical chemistries (including liver enzymes) and serum concentrations of microRNA-122 (miR-122, the processed form miR-122-5p), a biomarker of liver injury. The hepatotoxicants 4,4'-methylenedianiline (4,4'-MDA), allyl alcohol (AA), or carbon tetrachloride (CCl₄) were orally administered to male Sprague-Dawley rats for 1, 5, 14, or 28 days to induce liver damage. Formalin-fixed, paraffin-embedded liver sections were evaluated histologically for inflammation, fibrosis, necrosis, and lipid accumulation. Liver enzymes were measured in serum, and serum miR-122 concentrations were assessed by quantitative polymerase chain reaction (qPCR). Histologic features of hepatic injury dose-dependently increased in both severity and frequency. Increases in liver enzymes and bilirubin were more pronounced in response to AA or 4,4'-MDA than to CCl₄ at early time points. Elevated serum miR-122 levels in animals administered CCl₄, AA, or 4,4'-MDA were more strongly associated with degree of hepatic histopathology than with dosage. Given this sensitive expression pattern postexposure, liver-specific miR-122 may improve the diagnostic accuracy of early hepatic injury.