The role of microRNAs in diabetic nephropathy

Decoding the intricacies: a comprehensive analysis of microRNAs in the pathogenesis, diagnosis, prognosis and therapeutic strategies for COVID-19

The pandemic of coronavirus disease-19 (COVID-19), provoked by the appearance of a novel coronavirus named severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), required a worldwide healthcare emergency. This has elicited an immediate need for accelerated research into its mechanisms of disease, criteria for diagnosis, methods for forecasting outcomes, and treatment approaches. microRNAs (miRNAs), are diminutive RNA molecules, that are non-coding and participate in gene expression regulation post-transcriptionally, having an important participation in regulating immune processes. miRNAs have granted substantial interest in their impact on viral replication, cell proliferation, and modulation of how the host's immune system responds. This narrative review delves into host miRNAs' multifaceted roles within the COVID-19 context, highlighting their involvement in disease progression, diagnostics, and prognostics aspects, given their stability in biological fluids and varied expression profiles when responding to an infection. Additionally, we discuss complicated interactions between SARS-CoV-2 and host cellular machinery facilitated by host miRNAs revealing how dysregulation of host miRNA expression profiles advances viral replication, immune evasion, and inflammatory responses. Furthermore, it investigates the potential of host miRNAs as therapeutic agents, whether synthetic or naturally occurring, which could be harnessed to either mitigate harmful inflammation or enhance antiviral responses. However, searching more deeply is needed to clarify how host's miRNAs are involved in pathogenesis of COVID-19, its diagnosis processes, prognostic assessments, and treatment approaches for patients.

Exploring the role of miRNA in diabetic neuropathy: from diagnostics to therapeutics

Diabetic neuropathy (DN) is one of the major microvascular complications of diabetes mellitus affecting 50% of the diabetic population marred by various unmet clinical needs. There is a need to explore newer pathological mechanisms for designing futuristic regimens for the management of DN. There is a need for post-transcriptional regulation of gene expression by non-coding RNAs (ncRNAs) to finetune different cellular mechanisms with significant biological relevance. MicroRNAs (miRNAs) are a class of small ncRNAs (~ 20 to 24 nucleotide length) that are known to regulate the activity of ~ 50% protein-coding genes through repression of their target mRNAs. Differential expression of these miRNAs is associated with the pathophysiology of diabetic neuropathy via regulating various pathways such as neuronal hyperexcitability, inflammation, axonal growth, regeneration, and oxidative stress. Of note, the circulating and extracellular vesicular miRNAs serve as potential biomarkers underscoring their diagnostic potential. Recent pieces of evidence highlight the potential of miRNAs in modulating the initiation and progression of DN and the possibility of developing miRNAs as treatment options for DN. In this review, we have elaborated on the role of different miRNAs as potential biomarkers and emphasized their druggable aspects for promising future therapies for the clinical management of DN.

Applicability of mesenchymal stem cell-derived exosomes as a cell-free miRNA therapy and epigenetic modifiers for diabetes

Given that exosome nanovesicles constitute various growth factors, miRNAs and lncRNAs, they have implications for epigenetic modifications. Few studies have shown that exosomes from mesenchymal stem cells (MSCs) exhibit therapeutic effects on diabetic complications by substituting miRNAs and regulating histone modifications. Therefore, reversing epigenetic aberrations in diabetes may provide new insight into its treatment. This review discusses the impact of DNA and histone methylations on the development of diabetes and its complications. Further, we talk about miRNAs dysregulated in diabetic conditions and the possibility of utilizing mesenchymal stem cell (MSC) exosomes for the development of miRNA cell-free therapy and epigenetic modifiers in reversing diabetic-induced epigenetic alterations.

The Role of MicroRNA in the Pathogenesis of Diabetic Nephropathy

Diabetic nephropathy is one of the most common and severe complications of diabetes mellitus, affecting one in every five patients suffering from diabetes. Despite extensive research, the exact pathogenesis of diabetic nephropathy is still unclear. Several factors and pathways are known to be involved in the development of the disease, such as reactive oxygen species or the activation of the renin–angiotensin–aldosterone system. The expression of those proteins might be extensively regulated by microRNA. Recent research suggests that in diabetic nephropathy patients, the profile of miRNA is significantly changed. In this review, we focus on the actions of miRNA in various pathways involved in the pathogenesis of diabetic nephropathy and the clinical usage of miRNAs as biomarkers and therapeutic targets.

Pediatric Diabetic Nephropathy: Novel Insights from microRNAs

Diabetic nephropathy (DN) represents the most common microvascular complication in patients with diabetes. This progressive kidney disease has been recognized as the major cause of end-stage renal disease with higher morbidity and mortality. However, its tangled pathophysiology is still not fully known. Due to the serious health burden of DN, novel potential biomarkers have been proposed to improve early identification of the disease. In this complex landscape, several lines of evidence supported a critical role of microRNAs (miRNAs) in regulating posttranscriptional levels of protein-coding genes involved in DN pathophysiology. Indeed, intriguing data showed that deregulation of certain miRNAs (e.g., miRNAs 21, -25, -92, -210, -126, -216, and -377) were pathogenically linked to the onset and the progression of DN, suggesting not only a role as early biomarkers but also as potential therapeutic targets. To date, these regulatory biomolecules represent the most promising diagnostic and therapeutic options for DN in adult patients, while similar pediatric evidence is still limited. More, findings from these elegant studies, although promising, need to be deeper investigated in larger validation studies. In an attempt to provide a comprehensive pediatric overview in the field, we aimed to summarize the most recent evidence on the emerging role of miRNAs in pediatric DN pathophysiology.

Circulating mir-21 and mir-146a are associated with increased cytokines and CD36 in Algerian obese male participants

BACKGROUND

The microRNAs have come up as crucial mediators of energy balance and metabolic control. CD36 is potential biomarker of obesity and metabolic syndrome. This study investigates the concentration of miR-146a and miR-21 and CD 36 in blood samples of obese and healthy young participants. We assessed the association of mir-146a and mir-21 with inflammatory states in Algerian young participants.

METHODS

Our study included male obese, without co-morbidities (n = 29), and healthy participants (n = 13). miRNA and CD36 expression was measured by real-time RT-PCR, respectively, in serum and blood.

RESULTS

miR-146a and miR-21 concentrations were significantly decreased; however, CD36 expression was increased in obese subjects. Interestingly, miR-146a and miR-21 concentrations were negatively correlated to IL-6, TNF-α, and CD36 in obese participants.

CONCLUSION

We demonstrate that the downregulation of miR-146a and miR-21 was associated with upregulation of inflammatory state and increased CD36 expression in obese participants.

Polyphenols target miRNAs as a therapeutic strategy for diabetic complications

MiRNAs are a large group of non-coding RNAs which participate in different cellular pathways like inflammation and oxidation through transcriptional, post-transcriptional, and epigenetic regulation. In the post-transcriptional regulation, miRNA interacts with the 3'-UTR of mRNAs and prevents their translation. This prevention or dysregulation can be a cause of pathological conditions like diabetic complications. A huge number of studies have revealed the association between miRNAs and diabetic complications, including diabetic nephropathy, cardiomyopathy, neuropathy, retinopathy, and delayed wound healing. To address this issue, recent studies have focused on the use of polyphenols as selective and safe drugs in the treatment of diabetes complications. In this article, we will review the involvement of miRNAs in diabetic complications' occurrence or development. Finally, we will review the latest findings on targeting miRNAs by polyphenols like curcumin, resveratrol, and quercetin for diabetic complications therapy.

Role of microRNAs in COVID-19 with implications for therapeutics

COVID-19 is a pneumonia-like disease with highly transmittable and pathogenic properties caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which infects both animals and humans. Although many efforts are currently underway to test possible therapies, there is no specific FDA approved drug against SARS-CoV-2 yet. miRNA-directed gene regulation controls the majority of biological processes. In addition, the development and progression of several human diseases are associated with dysregulation of miRNAs. In this regard, it has been shown that changes in miRNAs are linked to severity of COVID-19 especially in patients with respiratory diseases, diabetes, heart failure or kidney problems. Therefore, targeting these small noncoding-RNAs could potentially alleviate complications from COVID-19. Here, we will review the roles and importance of host and RNA virus encoded miRNAs in COVID-19 pathogenicity and immune response. Then, we focus on potential miRNA therapeutics in the patients who are at increased risk for severe disease.

miRNA biomarkers in renal disease

Chronic kidney disease (CKD), which is characterized by the gradual loss of kidney function, is a growing worldwide problem due to CKD-related morbidity and mortality. There are no reliable and early biomarkers enabling the monitoring, the stratification of CKD progression and the estimation of the risk of CKD-related complications, and therefore, the search for such molecules is still going on. Numerous studies have provided evidence that miRNAs are potentially important particles in the CKD field. Studies indicate that some miRNA levels can be increased in patients with CKD stages III–V and hemodialysis and decreased in renal transplant recipients (miR-143, miR-145 and miR-223) as well as elevated in patients with CKD stages III–V, decreased in hemodialysis patients and even more markedly decreased in renal transplant recipients (miR-126 and miR-155). miRNA have great potential of being sensitive and specific biomarkers in kidney diseases as they are tissue specific and stable in various biological materials. Some promising non-invasive miRNA biomarkers have already been recognized in renal disease with the potential to enhance diagnostic accuracy, predict prognosis and monitor the course of disease. However, large-scale clinical trials enrolling heterogeneous patients are required to evaluate the clinical value of miRNAs.

LncRNA lnc-ISG20 promotes renal fibrosis in diabetic nephropathy by inducing AKT phosphorylation through miR-486-5p/NFAT5

Long non‐coding RNA (lncRNA) lnc‐ISG20 has been found aberrantly up‐regulated in the glomerular in the patients with diabetic nephropathy (DN). We aimed to elucidate the function and regulatory mechanism of lncRNA lnc‐ISG20 on DN‐induced renal fibrosis. Expression patterns of lnc‐ISG20 in kidney tissues of DN patients were determined by RT‐qPCR. Mouse models of DN were constructed, while MCs were cultured under normal glucose (NG)/high glucose (HG) conditions. The expression patterns of fibrosis marker proteins collagen IV, fibronectin and TGF‐β1 were measured with Western blot assay. In addition, the relationship among lnc‐ISG20, miR‐486‐5p, NFAT5 and AKT were analysed using dual‐luciferase reporter assay and RNA immunoprecipitation. The effect of lnc‐ISG20 and miR‐486/NFAT5/p‐AKT axis on DN‐associated renal fibrosis was also verified by means of rescue experiments. The expression levels of lnc‐ISG20 were increased in DN patients, DN mouse kidney tissues and HG‐treated MCs. Lnc‐ISG20 silencing alleviated HG‐induced fibrosis in MCs and delayed renal fibrosis in DN mice. Mechanistically, miR‐486‐5p was found to be a downstream miRNA of lnc‐ISG20, while miR‐486‐5p inhibited the expression of NFAT5 by binding to its 3'UTR. NFAT5 overexpression aggravated HG‐induced fibrosis by stimulating AKT phosphorylation. However, NFAT5 silencing reversed the promotion of in vitro and in vivo fibrosis caused by lnc‐ISG20 overexpression. Our collective findings indicate that lnc‐ISG20 promotes the renal fibrosis process in DN by activating AKT through the miR‐486‐5p/NFAT5 axis. High‐expression levels of lnc‐ISG20 may be a useful indicator for DN.

Roles of microRNAs in renal disorders related to primary podocyte dysfunction

Through the regulation of gene expression, microRNAs (miRNAs) are capable of modulating vital biological processes, such as proliferation, differentiation, and apoptosis. Several mechanisms control the function of miRNAs, including translational inhibition and targeted miRNA degradation. Through utilizing high-throughput screening methods, such as small RNA sequencing and microarray, alterations in miRNA expression of kidneys have recently been observed both in rodent models and humans throughout the development of chronic kidney disease (CKD) and acute kidney injury (AKI). The levels of miRNAs in urine supernatant, sediment, and exosomal fraction could predict novel biomarker candidates in different diseases of kidneys, including IgA nephropathy, lupus nephritis, and diabetic nephropathy. The therapeutic potential of administrating anti-miRNAs and miRNAs has also been reported recently. The present study is aimed at reviewing the state-of-the-art research with regards to miRNAs involved in renal disorders related to primary podocyte dysfunction by laying particular emphasis on Focal Segmental Glomerulosclerosis (FSGS), Minimal Change Disease (MCD) and Membranous Nephropathy (MN).

miR-142-5p regulates the progression of diabetic retinopathy by targeting IGF1

As one of leading causes of blindness, diabetic retinopathy (DR) is a progressive microvascular complication of diabetes mellitus (DM). Despite significant efforts have been devoted to investigate DR over the years, the molecular mechanisms still remained unclear. Emerging evidences demonstrated that microRNAs (miRNAs) were tightly associated with pathophysiological development of DR. Hence, this study was aimed to illustrate the role and molecular mechanisms of miR-412-5p in progression of DR. Streptozotocin (STZ) treatment in rats and human retinal endothelial cell (HREC) models were used to simulate DR conditions in vivo and in vitro. Hematoxylin-eosin (HE) staining was used to demonstrate the morphology of retinal tissues of rats. Qualitative real-time polymerase chain reaction (qRT-PCR) detected miR-142-5p and vascular endothelial growth factor (VEGF) expression levels. Cell counting kit-8 (CCK8) assay and immunofluorescence (IF) measured the cell proliferation rates. Western blot tested the expression status of IGF1/IGF1R-mediated signaling pathway. Dual-luciferase reporter assays demonstrated the molecular mechanism of miR-142-5p. miR-142-5p level was down-regulated in retinal tissues of DR rats and high glucose (HG)-treated HRECs. Insulin-like growth factor 1 (IGF1) was identified as a direct target of miR-142-5p. The reduced miR-142-5p level enhanced HRECs proliferation via activating IGF/IGF1R-mediated signaling pathway including p-PI3K, p-ERK, p-AKT, and VEGF activation, ultimately giving rise to cell proliferation. Either miR-142-5p overexpression or IGF1 knockdown alleviated the pathological effects on retinal tissues in DR rats. Collectively, miR-142-5p participated in DR development by targeting IGF1/p-IGF1R signaling pathway and VEGF generation. This miR-142-5p/IGF1/VEGF axis provided a novel therapeutic target for DR clinical treatment.

New insight into the role of isorhamnetin as a regulator of insulin signaling pathway in type 2 diabetes mellitus rat model: Molecular and computational approach

We intended to examine the molecular mechanism of action of isorhamnetin (IHN) to regulate the pathway of insulin signaling. Molecular analysis, immunofluorescence, and histopathological examination were used to assess the anti-hyperglycemic and insulin resistance lowering effects of IHN in streptozotocin /high fat diet-induced type 2 diabetes using Wistar rats. At the microscopic level, treatment with IHN resulted in the restoration of myofibrils uniform arrangement and adipose tissue normal architecture. At the molecular level, treatment with IHN at three different doses showed a significant decrease in m-TOR, IGF1-R & LncRNA-RP11-773H22.4. expression and it up-regulated the expression of AKT2 mRNA, miR-1, and miR-3163 in both skeletal muscle and adipose tissue. At the protein level, IHN treated group showed a discrete spread with a moderate faint expression of m-TOR in skeletal muscles as well as adipose tissues. We concluded that IHN could be used in the in ameliorating insulin resistance associated with type 2 diabetes mellitus.

Renoprotective effects of estrogen on acute kidney injury: the role of SIRT1

Acute kidney injury (AKI) is a common syndrome associated with high morbidity and mortality, despite progress in medical care. Many studies have shown that there are sex differences and different role of sex hormones particularly estrogens in kidney injury. In this regard, the incidence and rate of progression of kidney diseases are higher in men compared with women. These observations suggest that female sex hormone may be renoprotective. Silent information regulator 2 homolog 1 (SIRT1) is a histone deacetylase, which is implicated in multiple biologic processes in several organisms. In the kidneys, SIRT1 inhibits renal cell apoptosis, inflammation, and fibrosis. Studies have reported a link between SIRT1 and estrogen. In addition, SIRT1 regulates ERα expression and inhibition of SIRT1 activity suppresses ERα expression. This effect leads to inhibition of estrogen-responsive gene expression. In this text, we review the role of SIRT1 in mediating the protective effects of estrogen in the onset and progression of AKI.

MicroRNA-30/Cx43 axis contributes to podocyte injury by regulating ER stress in diabetic nephropathy

Background

The microRNA-30 family plays a critical role in the pathogenesis of podocyte injury. Cx43 plays an essential role in intercellular communication, which is essential for coordinated kidney function. This study was conducted to explore the function of microRNA-30s/Cx43 in podocyte injury in diabetic nephropathy (DN), both in vivo and in vitro.

Methods

SD rats were given streptozotocin (STZ) injections to induce DN. Podocytes were incubated in the medium in the presence or absence of high glucose (HG). The effects of the microRNA-30/Cx43 axis on DN and its underlying mechanisms were investigated by TUNEL assay, PAS, immunohistochemical staining, immunofluorescence staining, Western blot, RT-qPCR, RNA interference, and luciferase reporter assay. Podocytes were transfected with microRNA-30 family mimics, microRNA-30 family inhibitors, Cx43 siRNA, and negative controls to detect the effect of the microRNA-30/Cx43 axis. MicroRNA-30 family mimic AAVs, and microRNA-30 family inhibitor AAVs applied to regulate microRNA-30 family expression in the kidneys of the STZ-induced DN model rats to reveal the underlying mechanisms of the microRNA-30/Cx43 axis in DN.

Results

MicroRNA-30 family member expression was downregulated in HG-treated podocytes and the glomeruli of STZ-induced DN rats. Luciferase reporter assays confirmed Cx43 is a directed target of microRNA-30s. The overexpression of microRNA-30 family members attenuated the HG-induced podocyte injury and protected against podocyte apoptosis and endoplasmic reticulum stress (ERS) both in vivo and in vitro. Also, silencing Cx43 expression eased podocyte apoptosis, injury, and ERS induced by a HG+microRNA-30 family inhibitor. Double-immunofluorescence staining assays proved the co-localization of caspase12 and Cx43.

Conclusions

The overexpression of microRNA-30 family members prevents HG-induced podocyte injury and attenuates ERS by modulating Cx43 expression. The microRNA-30/Cx43/ERS axis might be a potential therapeutic target to treat DN.

MicroRNAs in diabetic nephropathy: From molecular mechanisms to new therapeutic targets of treatment

Despite considerable investigation in diabetic nephropathy (DN) pathogenesis and possible treatments, current therapies still do not provide competent prevention from disease progression to end-stage renal disease (ESRD) in most patients. Therefore, investigating exact molecular mechanisms and important mediators underlying DN may help design better therapeutic approaches for proper treatment. MicroRNAs (MiRNAs) are a class of small non-coding RNAs that play a crucial role in post-transcriptional regulation of many gene expression within the cells and present an excellent opportunity for new therapeutic approaches because their profile is often changed during many diseases, including DN. This review discusses the most important signaling pathways involved in DN and changes in miRNAs profile in each signaling pathway. We also suggest possible approaches for miRNA derived interventions for designing better treatment of DN.

Systemic inhibition of miR-451 increases fibrotic signaling and diminishes autophagic response to exacerbate renal damage in Tallyho/Jng mice

miRNAs provide fine tuning of gene expression via inhibition of translation. miR-451 has a modulatory role in cell cycling via downregulation of mechanistic target of rapamycin. We aimed to test whether chronic systemic inhibition of miR-451 would enhance renal fibrosis (associated with deranged autophagy). Adult TallyHo/Jng mice (obese insulin resistant) were randomized to two treatment groups to receive either miR-451 inhibition [via a locked nucleic acid construct] or a similar scrambled locked nucleic acid control for 8 wk. All mice were fed a high-fat diet (60% kcal from fat) ad libitum and humanely euthanized after 12 wk. Kidneys and blood were collected for analysis. Renal expression of miR-451 was sixfold lower in inhibitor-treated mice compared with control mice. miR-451 inhibition increased kidney weight and collagen and glycogen deposition. Blood chemistry revealed significantly higher Na⁺ and anion gap (relative metabolic acidosis) in inhibitor-treated mice. Western blot analysis and immunohistochemistry of the kidney revealed that the inhibitor increased markers of renal injury and fibrosis, e.g., kidney injury molecule 1, neutrophil gelatinase-associated lipocalin, transforming growth factor-β, 14-3-3 protein-ζ, mechanistic target of rapamycin, AMP-activated protein kinase-α, calcium-binding protein 39, matrix metallopeptidase-9, and the autophagy receptor sequestosome 1. In contrast, the inhibitor reduced the epithelial cell integrity marker collagen type IV and the autophagy markers microtubule-associated protein 1A/1B light chain 3B and beclin-1. Taken together, these results support a protective role for miR-451 in reducing renal fibrosis by enhancing autophagy in obese mice.

circ_0037128/miR-17-3p/AKT3 axis promotes the development of diabetic nephropathy

Circular RNAs (circRNAs) play vital roles in the development of diabetic nephropathy (DN). In this study, we investigated the function of circ_0037128 and molecular mechanism via which it regulates diabetic nephropathy development. It was found that expression of circ_0037128 was significantly increased in mouse DN model and high glucose treated mesangial cells (MCs), and circ_0037128 loss-of-function led to reduced cell proliferation and fibrosis in vitro. Moreover, miR-17-3p acts as competitive endogenous RNA (ceRNA) that directly interacts with circ_0037128 through its miRNA response elements (MREs). Consistently, expression of miR-17-3p was remarkably down-regulated in DN model, and negatively regulated cell proliferation and fibrosis. Further investigations revealed that AKT3 was the putative target of miR-17-3p, whose expression was elevated in DN model. In conclusion, we have characterized the function of a novel circ_0037128 and illustrated the significance of circ_0037128-miR-17-3p-AKT3 axis in DN pathogenesis.

MicroRNA-451 as an Early Predictor of Chronic Kidney Disease in Diabetic Nephropathy

Background

Diabetes mellitus is the leading cause of end-stage renal disease worldwide. Microalbuminuria is the cornerstone for the diagnosis of diabetic nephropathy. However, it is an inadequate marker for early diagnosis. MicroRNAs are not only new and promising markers for early diagnosis but also, but they may also play a role in the prevention of disease progression.

Methods

This study included ninety patients with type 2 DM in addition to 30 control subjects. MicroRNA-451 expression in blood and plasma using real-time PCR was evaluated in addition to the classic diabetic nephropathy markers (serum creatinine, urinary albumin, and eGFR).

Results

There was a significant difference between the studied groups versus control regarding serum creatinine, eGFR, urinary, and plasma microRNA-451 with p=0.0001. Patients with eGFR 60 ml/min/1.73 m² showed a significantly higher plasma microRNA-451 (29.6 ± 1.6) and significantly lower urinary microRNA-451 (21 ± 0.9) in comparison to patients with eGFR >60 ml/min/1.73 m² and p=0.0001. eGFR showed a positive correlation with urinary microRNA-451 and negative correlation with both plasma microRNA-451 and urinary albumin. Both plasma and urinary microRNA-451 are highly sensitive and specific markers for chronicity in diabetic nephropathy patients with sensitivity of 90.9% and 95.5% and specificity of 67.6% and 95.6%, respectively.

Conclusion

MicroRNA-451 is a promising early biomarker for chronic kidney disease in diabetic nephropathy with high sensitivity and specificity.

Diabetic Kidney Disease in Older People with Type 2 Diabetes Mellitus: Improving Prevention and Treatment Options

Age-related metabolic and renal changes predispose older people to an increased risk of diabetes mellitus and diabetic kidney disease, respectively. As the prevalence of the ageing population is increasing, because of increased life expectancy, the prevalence of older people with diabetic kidney disease is likely to increase. Diabetic kidney disease is associated with an increased risk of adverse outcomes and increased costs to healthcare systems. The management includes promotion of a healthy lifestyle and control of cardiovascular risk factors such as hyperglycaemia, hypertension and dyslipidaemia. Older people are a heterogeneous group of people from a community-living fit and independent person to a fully dependent individual residing in a care home. Therefore, management in this age group should be based on a patient's functional level adopting tight metabolic control in the fit individual and relaxed targets in the frail person. However, despite the maximum available therapy, a significant number of patients with diabetic kidney disease still progress to renal failure and experience adverse cardiac outcomes. Therefore, future research is required to explore methods of early detection of diabetic kidney disease and to investigate novel therapeutic interventions to further improve the outcomes.

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.

miR-218 Expressed in Endothelial Progenitor Cells Contributes to the Development and Repair of the Kidney Microvasculature

Ischemia due to hypoperfusion is one of the most common forms of acute kidney injury. We hypothesized that kidney hypoxia initiates the up-regulation of miR-218 expression in endothelial progenitor cells (EPCs) to guide endocapillary repair. Murine renal artery-derived EPCs (CD34+/CD105-) showed down-regulation of mmu-Mir218-5p/U6 RNA ratio after ischemic injury, while in human renal arteries, MIR218-5p expression was up-regulated after ischemic injury. MIR218 expression was clarified in cell culture experiments in which increases in both SLIT3 and MIR218-2-5p expressions were observed after 5 minutes of hypoxia. ROBO1 transcript, a downstream target of MIR218-2-5p, showed inverse expression to MIR218-2-5p. EPCs transfected with a MIR218-5p inhibitor in three-dimensional normoxic culture showed premature capillary formation. Organized progenitor cell movement was reconstituted when cells were co-transfected with Dicer siRNA and low-dose Mir218-5p mimic. A Mir218-2 knockout was generated to assess the significance of miR-218-2 in a mammalian model. Mir218-2-5p expression was decreased in Mir218-2-/- embryos at E16.5. Mir218-2-/- decreased CD34+ angioblasts in the ureteric bud at E16.5 and were nonviable. Mir218-2+/- decreased peritubular capillary density at postnatal day 14 and increased serum creatinine after ischemia in adult mice. Systemic injection of miR-218-5p decreased serum creatinine after injury. These experiments demonstrate that miR-218 expression can be triggered by hypoxia and modulates EPC migration in the kidney.

MicroRNAs and Risk Factors for Diabetic Nephropathy in Egyptian Children and Adolescents with Type 1 Diabetes

PURPOSE

Currently available markers for early detection of diabetic nephropathy (DN), the leading cause of end stage renal disease, have some limitations. There is insufficient evidence from previous studies about the role of several circulating microRNAs (miRNAs) in the early development of DN. This study aimed to describe the expression of miRNA-377, miRNA-93, miRNA-25, miRNA-216a, and miRNA-21 in a sample of type 1 diabetic children and adolescents to explore their association with DN and some indices of kidney injury.

PATIENTS AND METHODS

Seventy type 1 diabetic patients, with 5 years' duration of diabetes or more, were recruited from Children's Hospital, Faculty of Medicine, Cairo University. Quantitative real-time reverse-transcription PCR (qRT-PCR) was used to measure the expression of the above mentioned miRNAs in serum and to assess its association with DN, and the studied risk factors.

RESULTS

There was a significantly higher percentage of up-regulation of miRNA-377 and miRNA-93 (P=0.03, 0.02, respectively) in addition to significant down-regulation of miRNA-25 (P=0.01) in patients with DN than in patients without DN. In patients with DN, expression of miR-216a was significantly negatively correlated with creatinine (r=-0.4, P=0.04) and positively correlated with eGFR using creatinine (r=0.5, P=0.03). In the same group, expression of miR-21 was positively correlated with urinary cystatin C (r=0.6, P=0.01) and was negatively correlated with e-GFR using cystatin c (r=-0.6, P=0.01). miRNA-93 was associated with increased risk (odds ratio=15, 95% CI=12.03-24.63, P=0.01), while miRNA-25 was associated with decreased risk for albuminuria (odds ratio=0.15, 95% CI=0.08-0.55, P=0.03).

CONCLUSION

miRNA-377, miRNA-93, miRNA-216a, and miRNA-21 may be implicated in the pathogenesis of DN, while miRNA-25 may have a reno-protective role. More studies are needed to document the value of these miRNAs as diagnostic biomarkers as well as therapeutic targets in DN.

MicroRNA-451 inhibits inflammation and proliferation of glomerular mesangial cells through down-regulating PSMD11 and NF-κB p65

The present study aimed to investigate the regulatory roles of microRNA-451 (miR-451) on the inflammation and proliferation of glomerular mesangial cells (GMCs) under high-glucose condition, and reveal the potential mechanisms related to 26S proteasome non-ATPase regulatory subunit 11 (PSMD11) and nuclear factor-κ B (NF-κB) signaling. The interaction between PSMD11 and miR-451 was identified by dual luciferase reporter (DLR) gene assay. GMCs were treated with 5.6 mmol/l (normal, L-GMCs) and 30 mmol/l glucose (high-glucose, H-GMCs), respectively. After transfecting with pcDNA3.1-PSMD11 and/or miR-451 mimics, the expression of miR-451, PSMD11, inhibitor of NF-κB α (IκBα), phosphorylated IκBα (p-IκBα), NF-κB p65, COX-2, and cyclinD1 were detected in H-GMCs by quantitative real-time PCR (qRT-PCR) and/or Western blot. The levels of interleukin (IL)-1β, IL-6, and IL-8, cell cycle, and viability was detected by enzyme-linked immunosorbent assay, flow cytometry, and MTT assay, respectively. MiR-451 was up-regulated in H-GMCs, and negatively regulated its target PSMD11 (P<0.05). H-GMCs exhibited significantly higher levels of IL-1β, IL-6, and IL-8, cell viability, and p-IκBα, NF-κB, COX-2, and cyclinD1 expression than L-GMCs (P<0.05). The transfection of miR-451 mimics significantly decreased the levels of IL-1β, IL-6, and IL-8, inhibited the cell viability via blocking cells in G0/G1 phase, and down-regulated p-IκBα, NF-κB p65, COX-2, and cyclinD1 in H-GMCs (P<0.05). The regulatory effects of miR-451 mimics on H-GMCs were reversed by the transfection of PSMD11 (P<0.05). The up-regulation of miR-451 inhibits the inflammation and proliferation of H-GMCs through down-regulating PSMD11 and NF-κB p65.

The circulating exosomal microRNAs related to albuminuria in patients with diabetic nephropathy

BACKGROUND

Diabetic nephropathy (DN) is associated with high risk of cardiovascular disease and mortality. Exosomal microRNAs (miRNAs) regulate gene expression in a variety of tissues and play important roles in the pathology of various diseases. We hypothesized that the exosomal miRNA profile would differ between DN patients and patients without nephropathy.

METHODS

We prospectively enrolled 74 participants, including healthy volunteers (HVs), diabetic patients without nephropathy, and those with DN. The serum exosomal miRNA profiles of participants were examined using RNA sequencing.

RESULTS

The expression levels of 107 miRNAs differed between HVs and patients without DN, whereas the expression levels of 95 miRNAs differed between HVs and patients with DN. Among these miRNAs, we found 7 miRNAs (miR-1246, miR-642a-3p, let-7c-5p, miR-1255b-5p, let-7i-3p, miR-5010-5p, miR-150-3p) that were uniquely up-regulated in DN patients compared to HVs, and miR-4449 that was highly expressed in DN patients compared to patients without DN. A pathway analysis revealed that these eight miRNAs are likely involved in MAPK signaling, integrin function in angiogenesis, and regulation of the AP-1 transcription factor. Moreover, they were all significantly correlated with the degree of albuminuria.

CONCLUSIONS

Patients with DN have a different serum exosomal miRNA profile compared to HVs. These miRNAs may be promising candidates for the diagnosis and treatment of DN and cardiovascular disease.

miR‑132 inhibits high glucose‑induced vascular smooth muscle cell proliferation and migration by targeting E2F5

The dysregulated behavior of vascular smooth muscle cells (VSMCs) serves an important role in the pathogenesis of cardiovascular diseases in diabetes. The present study aimed to investigate the effects of microRNA (miR)‑132 on the proliferation and migration of VSMCs under high glucose conditions to mimic diabetes. We observed that the expression of miR‑132 was significantly decreased and that of E2F transcription factor 5 (E2F5) was upregulated in high glucose (HG)‑treated VSMCs or those obtained from diabetic rats. A dual luciferase reporter gene assay revealed that miR‑132 could specifically bind to the 3'‑untranslated region of E2F5 and significantly suppress the luciferase activity. The proliferation and migration of diabetic rat or HG‑treated VSMCs were increased compared with non‑diabetic rat VSMCs and those under normal glucose conditions. Upregulation of miR‑132 significantly inhibited the proliferation and migration of diabetic rat VSMCs; similar effects were observed following E2F5 downregulation. The inhibitory effects of miR‑132 on the proliferation and migration of HG‑treated VSMCs could be reversed by E2F5 overexpression. In conclusion, miR‑132 was proposed to inhibit the proliferation and migration of diabetic rat or high‑glucose‑treated VSMCs by targeting E2F5. The findings of the present study suggested that increasing the expression of miR‑132 may serve as a novel therapeutic approach to inhibit the progression of cardiovascular disease in diabetes.

Identification of miRNAs-genes regulatory network in diabetic nephropathy based on bioinformatics analysis

MicroRNAs (miRNAs) play a great contribution to the development of diabetic nephropathy (DN). The aim of this study was to explore potential miRNAs-genes regulatory network and biomarkers for the pathogenesis of DN using bioinformatics methods.Gene expression profiling data related to DN (GSE1009) was obtained from the Gene Expression Omnibus (GEO) database, and then differentially expressed genes (DEGs) between DN patients and normal individuals were screened using GEO2R, followed by a series of bioinformatics analyses, including identifying key genes, conducting pathway enrichment analysis, predicting and identifying key miRNAs, and establishing regulatory relationships between key miRNAs and their target genes.A total of 600 DEGs associated with DN were identified. An additional 7 key DEGs, including 6 downregulated genes, such as vascular endothelial growth factor α (VEGFA) and COL4A5, and 1 upregulated gene (CCL19), were identified in another dataset (GSE30528) from glomeruli samples. Pathway analysis showed that the down- and upregulated DEGs were enriched in 14 and 6 pathways, respectively, with 7 key genes mainly involved in extracellular matrix-receptor interaction, PI3K/Akt signaling, focal adhesion, and Rap1 signaling. The relationships between miRNAs and target genes were constructed, showing that miR-29 targeted COL4A and VEGFA, miR-200 targeted VEGFA, miR-25 targeted ITGAV, and miR-27 targeted EGFR.MiR-29 and miR-200 may play important roles in DN. VEGFA and COL4A5 were targeted by miR-29 and VEGFA by miR-200, which may mediate multiple signaling pathways leading to the pathogenesis and development of DN.

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.

A comprehensive review on miR-451: A promising cancer biomarker with therapeutic potential

MicroRNAs (miRNAs) are proposed as a family of short noncoding molecules able to manage and control the expression of the gene targets at the posttranscriptional level. They contribute in several fundamental physiological mechanisms as well as a verity of human and animal diseases such as cancer progression. Among these tiny RNAs, miR-451 placed on chromosome 17 at 17q11.2 presents an essential role in many biological processes in health condition and also in pathogenesis of different diseases. Besides, it has been recently considered as a valuable biomarker for cancer detection, prognosis and treatment. Therefore, this review will provide the critical functions of miR-451 on biological mechanisms including cell cycle and proliferation, cell survival and apoptosis, differentiation and development as well as disease initiation and progression such as tumor formation, migration, invasion, and metastasis.

Transcription coactivator p300 promotes inflammation by enhancing p65 subunit activation in type 2 diabetes nephropathy

BACKGROUND

p300, a transcription co-activator, plays an important role in multicellular organisms and inflammation. However, the mechanism of p300 in type 2 diabetes nephropathy (T2DN) remains largely unknown. Our aim is to explore the mechanism of p300 in T2DN.

METHODS

A T2DN mice model was induced by db/db transgenic mice or a high fat diet for 24 weeks. The levels of IL-6 and TNF-α were examined by real-time PCR (RT-PCR) in the renal cortex and by an enzyme linked immunosorbent assay (ELISA) in the serum of the T2DN mice. p300 siRNA was used to knockdown the expression of p300, and His-tagged-p300 plasmid was used to overexpress the p300 protein level in podocytes. Hematoxylin-eosin staining (H&E) and Masson trichrome analysis were used to detect the kidney pathology in T2DN.

RESULTS

The levels of IL-6 and TNF-α were significantly increased in T2DN. p300 was significantly increased in T2DN. Consistently, p300 silencing significantly suppressed the inflammatory response and the overexpression of p300 significantly promoted the production of IL-6 and TNF-α in T2DN.

CONCLUSIONS

This study demonstrated that the production of IL-6 and TNF-α, and the expression of p300, were increased in T2DN. Furthermore, P300 significantly promoted the activation of the NF-κB subunit p65 through a direct association with p65 in T2DN, subsequently enhancing the production of IL-6 and TNF-α.

MicroRNA-664 targets paired box protein 6 to inhibit the oncogenicity of pancreatic ductal adenocarcinoma

The abnormal expression of microRNAs (miRNAs or miRs) with oncogenic or tumor‑suppressive roles in pancreatic ductal adenocarcinoma (PDAC) has been widely reported in recent years, and these dysregulated miRNAs are implicated in the formation and progression of PDAC. Therefore, an investigation into the functional roles of miRNAs in PDAC may facilitate the identification of effective therapeutic targets. miRNA‑664 (miR‑664) has been found to be aberrantly expressed and to play crucial roles in several human cancer types. However, the expression pattern and functional roles of miR‑664 in the malignant capacity of PDAC have yet to be elucidated. In this study, the results revealed that miR‑664 was clearly downregulated in PDAC tissues and cell lines. The low miR‑664 expression was strongly associated with pathological T stage and lymph node metastasis of the patients with PDAC. Patients with PDAC with a low miR‑664 expression had a poorer overall survival and a worse disease‑free survival than those patients with a high miR‑664 level. Functional experiments suggested that exogenous miR‑664 expression suppressed the growth and metastasis of PDAC cells in vitro, whereas miR‑664 downregulation exerted the opposite effects. In addition, miR‑664 suppressed the tumor growth of PDAC cells in vivo. Mechanistically, paired box protein 6 (PAX6) was identified as a direct target gene of miR‑664 in PDAC cells. Furthermore, PAX6 was upregulated in PDAC tissues, and its upregulation inversely correlated with miR‑664 levels. Moreover, the silencing of PAX6 mimicked the effects of miR‑664 upregulation in PDAC cells, and the recovered expression of PAX6 eliminated the effects of miR‑664 on PDAC cells. Notably, miR‑664 could inhibit the activation of PI3K/Akt pathway in PDAC cells in vitro and in vivo. Cumulatively, these results indicate an important role of the miR‑664/PAX6 pathway in suppressing the aggressiveness of PDAC cells, suggesting that miR‑664 may be an attractive therapeutic target for the treatment of patients with this fatal disease.

LncRNA TUG1 ameliorates diabetic nephropathy by inhibiting miR-21 to promote TIMP3-expression

Diabetic nephropathy (DN) is one of the most important microvascular diseases in diabetic patients and has been the first cause of end stage renal disease (ESRD). In this study, we are aims to investigate the genetic mechanisms of lncRNA in the regulation of DN renal fibrosis. First, we have found that the expression of lncRNA TUG1 in db/db DN mice kidney tissue and high glucose-stimulated NRK-52E cells were down-regulated and the overexpression of lncRNA TUG1 could inhibit cell fibrosis of high glucose-stimulated of NRK-52E. Second, online software program Starbase predicts that miR-21 is a target gene of lncRNA TUG1 and TIMP3 is the target gene of miR-21, which have been verified by luciferase reporter assay and RNA Binding Protein Immunoprecipitation (RIP). Last, the renal fibrosis in DN mice and cell fibrosis in high glucose-stimulated NRK-52E cells were also evaluated. We have proven that overexpression of lncRNA TUG1 can promote the expression of TIMP3 through targeting the miR-21, thereby inhibiting cell fibrosis in high glucose-stimulated NRK-52E cells and renal fibrosis in DN mice. Our results indicated that lncRNA TUG1 could indirectly regulated the expression of TIMP3 by targeting miR-21. LncRNA TUG1 inhibited high glucose-stimulated NRK-52E cell fibrosis and renal fibrosis in DN mice, which provides a theoretical basis for the treatment of DN fibrosis.

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.

miR-98-5p Alleviated Epithelial-to-Mesenchymal Transition and Renal Fibrosis via Targeting Hmga2 in Diabetic Nephropathy

Recently, microRNAs have been recognized as crucial regulators of diabetic nephropathy (DN) development. Epithelial-to-mesenchymal transition (EMT) can play a significant role in tubulointerstitial fibrosis, and it is a hallmark of diabetic nephropathy progression. Nevertheless, the function of miR-98-5p in the modulation of EMT and renal fibrosis during DN remains barely investigated. Hence, identifying the mechanisms of miR-98-5p in regulating EMT and fibrosis is of huge significance. In our present research, decreased miR-98-5p was demonstrated in db/db mice and mice mesangial cells treated with the high dose of glucose. Meanwhile, activated EMT and increased fibrosis was accompanied with the decrease of miR-98-5p in vitro and in vivo. Additionally, to further find out the roles of miR-98-5p in DN development, overexpression of miR-98-5p was applied. Firstly, in vivo investigation exhibited that elevation of miR-98-5p restrained proteinuria, serum creatinine, BUN, the EMT process, and fibrosis. Furthermore, high glucose was able to promote mice mesangial cell proliferation, EMT process, and induced renal fibrosis, which could be prevented by overexpression of miR-98-5p. Moreover, high mobility group A (HMGA2) can exhibit an important role in diverse biological processes. Here, HMGA2 was investigated as a target of miR-98-5p currently. Luciferase reporter assay was conducted and the correlation of miR-98-5p and HMGA2 was validated. Moreover, it was displayed that HMGA2 was remarkably elevated in db/db mice and mice mesangial cells. Furthermore, miR-98-5p strongly depressed HMGA2 protein and mRNA levels in mice mesangial cells. Overall, these revealed miR-98-5p could suppress the EMT process and renal fibrosis through targeting HMGA2 in DN.

miR29b regulates aberrant methylation in In-Vitro diabetic nephropathy model of renal proximal tubular cells

The role of DNA methylation has not been enough explored in pathophysiology of diabetic nephropathy (DN). However, according to recent reports it has been inferred that hypermethylation could be one of the principle cause associated with the enhancement of DN. An interrelationship between miR29b and DNA methylation has been studied via in-silico analysis. We have validated that miR29b prominently targets DNA methyl transferase (DNMT), specifically DNMT1, DNMT3A and DNMT3B. We have developed in vitro DN model using renal proximal tubule epithelial cells (RPTECs), contributed to a significant alleviation in RNA and protein expression levels of DNMT3A, DNMT3B and DNMT1. The developed model has also demonstrated downregulation in expression of miR29b. Our studies have also suggested that miR29b targets DNMT1 via targeting its transcription factor SP1. In addition to this, downregulation of a specific biomarker for kidney injury, tubular kidney injury molecule-1 (KIM-1) and fibrosis causing glycoprotein i.e. fibronectin, was also demonstrated. Hence, the developed model revealed that hypermethylation is a key factor incorporated in DN, and miR29b could effectively ameliorate defensive actions in DN pathogenesis.

A Network Pharmacology Approach to Uncover the Mechanisms of Shen-Qi-Di-Huang Decoction against Diabetic Nephropathy

Shen-Qi-Di-Huang decoction (SQDHD), a well-known herbal formula from China, has been widely used in the treatment of diabetic nephropathy (DN). However, the pharmacological mechanisms of SQDHD have not been entirely elucidated. At first, we conducted a comprehensive literature search to identify the active constituents of SQDHD, determined their corresponding targets, and obtained known DN targets from several databases. A protein-protein interaction network was then built to explore the complex relations between SQDHD targets and those known to treat DN. Following the topological feature screening of each node in the network, 400 major targets of SQDHD were obtained. The pathway enrichment analysis results acquired from DAVID showed that the significant bioprocesses and pathways include oxidative stress, response to glucose, regulation of blood pressure, regulation of cell proliferation, cytokine-mediated signaling pathway, and the apoptotic signaling pathway. More interestingly, five key targets of SQDHD, named AKT1, AR, CTNNB1, EGFR, and ESR1, were significant in the regulation of the above bioprocesses and pathways. This study partially verified and predicted the pharmacological and molecular mechanisms of SQDHD on DN from a holistic perspective. This has laid the foundation for further experimental research and has expanded the rational application of SQDHD in clinical practice.

Proteasome subunit-α type-6 protein is post-transcriptionally repressed by the microRNA-4490 in diabetic nephropathy

A common complication of both type I and type II diabetes is nephropathy, characterized by accumulation of extracellular matrix in the glomerular mesangium. This indicates a central role of mesangial cells in the pathophysiology of diabetic nephropathy. Using the proteomic approach, it was earlier elucidated in a rat model that the proteasome subunit-α type-6 protein (PSMA6) is suppressed in the renal cortex in nephropathic kidney. However, the underlying mechanism effecting suppression of PSMA6 protein in the renal cortex is not yet known. Twenty diabetic patients were enrolled and the expression level of PSMA6 in them was detected by immunohistochemistry. The protein and mRNA expression levels of PSMA6 in NRK-52E cells under high glucose condition were determined by Western blot and quantitative real-time PCR, respectively. Dual luciferase assay was used to detect the relationship of PSMA6 and miR-4490. Our results show that PSMA6 protein is down-regulated in patients with diabetic nephropathy compared with healthy control. Using the NRK-52E cell line cultured under high glucose condition as an in vitro model of diabetic nephropathy, we show that loss of PSMA6 protein expression occured independent of changes the in PSMA6 mRNA expression. We next elucidate that PSMA6 mRNA is post-transcriptionally regulated by the microRNA (miRNA)-4490, whose expression is inversely correlated to PSMA6 protein expression. Using reporter assays we show that PSMA6 is a direct target of the miR-4490. Exogenous manipulation of miR-4490 levels modulated expression of PSMA6, indicating that miR-4490 can be tested as a biomarker for nephropathy in diabetic patients.

Angpt2 Induces Mesangial Cell Apoptosis through the MicroRNA-33-5p-SOCS5 Loop in Diabetic Nephropathy

Diabetic nephropathy (DN) is the leading cause of end-stage renal disease. Mesangial cell (MC) loss is correlated with worsening renal function in DN. Disturbance of angiopoietin (Angpt)/Tie ligand-receptor system causes inflammation and abnormal angiogenesis. This association between elevated circulating Angpt2 and poor renal outcome has been in DN patients. However, the pathogenic role of Angpt2 in the MCs remains unknown. We found serum Angpt2 levels were elevated in type 2 diabetes mellitus (DM) patients and db/db mice, which correlated with albuminuria. Angpt2 synergistically induced MC apoptosis under high glucose (HG), and miR-33-5p regulated Angpt2-inducing MC apoptosis treated with HG. Loss of miR-33-5p increased suppressor of cytokine signaling 5 (SOCS5), leading to the inhibition of Janus kinase 1 and signal transducer and activator of transcription 3 signaling transduction. Elevated expression of SOCS5 was found in the MCs in kidney sections of both db/db mice and type 2 DM patients. Decreased miR-33-5p levels were found in the urine of db/db mice and type 2 DM patients, and miR-33-55p levels negatively correlated with albuminuria. Angpt2 leads to MC apoptosis via the miR-33-5p-SOCS5 loop in DN. miR-33-5p is predictive of kidney injury in DN. These findings may provide future applications in predicting renal dysfunction and the therapeutic potential of DN.

MiR-130b increases fibrosis of HMC cells by regulating the TGF-β1 pathway in diabetic nephropathy

Basement membrane thickening, glomerular hypertrophy, and deposition of multiple extracellular matrix characterize the pathological basis of diabetic nephropathy (DN), a condition which ultimately leads to glomerular and renal interstitial fibrosis. Here, we identified a novel microRNA, miR-130b, and investigated its role and therapeutic efficacy in alleviating DN. Introduction of miR-130b dramatically increased cell growth and fibrosis in DN cells. We found that transforming growth factor (TGF)-β1 was a functional target of miR-130b in human glomerular mesangial cells (HMCs) and overexpression of miR-130b increased expressions of the downstream signaling molecules of TGF-β1, t-Smad2/3, p-Smad2/3, and SMAD4. An ectopic application of miR-130b increased messenger RNA and protein expressions of collagen type I (colI), colIV, and fibronectin, whose expression levels were correlated with the expression of miR-130b. Taken together, the findings of this study reveal that miR-130b in HMC cells plays an important role in fibrosis regulation and may thus be involved with the pathogenesis of DN. Therefore, miR-130b may serve as a novel therapeutic target for the prevention and the treatment of DN.

Triptolide Attenuates Renal Tubular Epithelial-mesenchymal Transition Via the MiR-188-5p-mediated PI3K/AKT Pathway in Diabetic Kidney Disease

Triptolide possesses the trait of renal protection. Epithelial-mesenchymal transition (EMT) is closely linked to the pathogenesis of diabetic kidney disease (DKD). MicroRNAs have recently emerged as critical regulators of DKD. However, it is poorly understood whether triptolide alleviates renal EMT by regulating microRNAs in DKD. In this study, we found that triptolide decreased albuminuria, improved the renal structure and reduced renal EMT in rats with DKD. Furthermore, activation of the PI3K/AKT signaling pathway was increased in diabetic rats, which was partly reversed by triptolide. Triptolide also alleviated glucose-induced EMT in HK-2 cells in vitro. PI3K/AKT signaling pathway activation was reduced after triptolide treatment. Moreover, triptolide decreased the increase in miR-188-5p expression stimulated by high glucose levels in HK-2 cells. miR-188-5p inhibited PTEN expression by directly interacting with the PTEN 3'-untranslated region. Additionally, downregulation of miR-188-5p, which imitates the effects of triptolide, attenuated the activation of the PI3K/AKT pathway and HG-induced EMT, whereas miR-188-5p overexpression reversed the effects of triptolide on the PI3K/AKT pathway and EMT. In conclusion, we demonstrated that triptolide ameliorates renal EMT via the PI3K/AKT signaling pathway through the interaction between miR-188-5p and PTEN, indicating that miR-188-5p may be a therapeutic target of triptolide in DKD.

miR-192 is upregulated in T1DM, regulates pancreatic β-cell development and inhibits insulin secretion through suppressing GLP-1 expression

MicroRNAs (miRs) post-translationally regulate gene expression by specifically binding to the mRNA of their target genes. The aim of the present study was to determine the effect of miR-192 on pancreatic β-cell development. The serum levels of miR-192 in type 1 diabetes mellitus (T1DM) and streptozotocin-induced rats were determined, and were revealed to be elevated compared with those in healthy patients and normal rats, respectively. Western blot and reverse transcription-quantitative polymerase chain reaction analysis indicated that miR-192 suppressed the expression of glucagon-like peptide-1 (GLP-1), a potent insulin secretagogue. Ectopic expression of miR-192 inhibited cell proliferation and promoted apoptosis of NIT-1 cells, while miR-192 inhibitor had the opposite effect. Collectively, the present results revealed that miR-192 was elevated in T1DM, and is implicated in pancreatic β-cell development through regulation of cell proliferation and apoptosis, thereby suppressing insulin secretion. Furthermore, miR-192 suppressed GLP-1 expression, thereby further promoting T1DM. The present study suggested that miR-192 is a novel molecular target for the management or prevention of T1DM.

MicroRNA-22 Promotes Renal Tubulointerstitial Fibrosis by Targeting PTEN and Suppressing Autophagy in Diabetic Nephropathy

Renal tubulointerstitial fibrosis (TIF) is a major feature of diabetic nephropathy (DN). There is increasing evidence demonstrating that microRNAs act as key players in the regulation of autophagy and are involved in DN. However, the exact link among microRNAs, autophagy, and TIF in DN is largely unknown. In this study, our results showed that TIF was observed in DN rats together with obvious autophagy suppression. Moreover, microRNA-22 (miR-22) was upregulated and associated with reduced expression of its target gene phosphatase and tensin homolog (PTEN) in both the kidneys of DN rats and high glucose-cultured NRK-52E cells. Intriguingly, induction of autophagy by rapamycin antagonized high glucose-induced collagen IV (Col IV) and α-SMA expression. In addition, ectopic expression of miR-22 suppressed autophagic flux and induced the expression of Col IV and α-SMA, whereas the inhibition of endogenous miR-22 effectively relieved high glucose-induced autophagy suppression and the expression of Col IV and α-SMA in NRK-52E cells. Overexpression of PTEN protectively antagonized high glucose- and miR-22-induced autophagy suppression and the expression of Col IV. Therefore, our findings indicated that miR-22 may promote TIF by suppressing autophagy partially via targeting PTEN and represents a novel and promising therapeutic target for DN.

Microribonucleic acid-192 as a specific biomarker for the early diagnosis of diabetic kidney disease

AIMS/INTRODUCTION

To evaluate the diagnostic value of microribonucleic acid (miR) as biomarkers in patients with diabetic kidney disease (DKD).

MATERIALS AND METHODS

A total of 230 diabetes mellitus patients and 53 healthy participants were enrolled, and the diabetes mellitus group was further divided into normoalbuminuria, microalbuminuria and large amount of albuminuria group. MiRs of serum and urine were quantificated using real-time polymerase chain reaction. General clinical information was collected and analyzed for the risk factors. Cut-off values of diagnosis sensitivity were determined by receiver operating characteristic curves and the Youden Index.

RESULTS

Compared with the healthy participants, the expression of miR-192 in serum decreased, whereas in urine it increased with the progression of DKD. The expression of both serum and urine miR-126 increased in the diabetes mellitus group, but no significant change was obtained among the DKD groups. The area under the curve receiver operating characteristic of both serum and urine miR-192 was higher than that of the albumin-to-creatinine ratio. Combined detection of urine and serum miR-192 has a higher specificity and lower misdiagnosis rate.

CONCLUSIONS

Both serum and urinary miR-192 could be a potential biomarker of DKD, playing a crucial role in the prevention and treatment of DKD.

Targeting heme oxygenase-1 in early diabetic nephropathy in streptozotocin-induced diabetic rats

Diabetic nephropathy (DN) is one of the most common microvascular diabetic complications. This study was designed to evaluate the possible protective effect and underlying mechanisms of HO-1 induction in streptozotocin (STZ)-induced early DN in rats. The diabetic rats were divided into three groups: STZ-diabetic, cobalt protoporphyrin (CoPP)-treated diabetic, and zinc protoporphyrin IX (ZnPP)-treated diabetic groups. Compared to the STZ-diabetic group, CoPP-induced HO-1 upregulation improved the diabetic state and renal functional parameters, suppressed the renal proinflammatory marker, NF-κB, abrogated the elevated renal hydroxyprolin, and decreased the enhanced renal nicotinamide adenine dinucleotide phosphate oxidase activity with parallel reduction of urinary oxidative stress markers. On the contrary, treatment with ZnPP abrogated HO-1 levels, aggravated the diabetic condition with further increases in renal oxidative stress, fibrotic and inflammatory markers, and exacerbated renal dysfunction in diabetic animals. These findings suggest that the reduced diabetic renal injury upon HO-1 induction implicates the role of HO-1 induction as a potential treatment for DN.