High glucose down-regulates microRNA-181a-5p to increase pro-fibrotic gene expression by targeting early growth response factor 1 in HK-2 cells

DNA methylation of miR-181a-5p mediated by DNMT3b drives renal interstitial fibrosis developed from acute kidney injury

Aim: To explore the role of miR-181a-5p in the progression of acute kidney injury (AKI) to renal interstitial fibrosis (RIF) from the perspective of DNA methylation. Materials & methods: The role of miR-181a-5p was confirmed by collecting clinical samples, injecting miR-181a-5p agomir into tail vein, and transfecting miR-181a-5p mimic in vitro. The mechanism of miR-181a-5p's influence on AKI induced RIF was investigated by methylation-specific PCR, bioinformatic analysis, transcriptome sequencing and so on. Results: MiR-181a-5p plays an important role in AKI induced RIF. DNMT3b-mediated miR-181a-5p promoter hypermethylation is the main reason for the downregulation of miR-181a-5p. HDAC9 and SNAI2 are direct targets of miR-181a-5p. Conclusion: Hypermethylation of miR-181a-5p promoter mediated by DNMT3b promotes AKI induced RIF by targeting HDAC9 and SNAI2.

Tumor-mesothelium HOXA11-PDGF BB/TGF β1-miR-181a-5p-Egr1 feedforward amplifier circuity propels mesothelial fibrosis and peritoneal metastasis of gastric cancer

A proportion of gastric cancer (GC) patients suffer from peritoneal metastasis (PM) in the late stage of tumor and these patients have a poor prognosis. To provide more care for GC patient with PM, a deeper exploration of the molecular characteristics of GC-PM is needed. Here we performed the in vitro and in vivo study to illustrate the effect of HOXA11 over-expressed GC cells on peritoneal mesothelial cells (HMrSV5), transcriptomics analyses of HMrSV5 cells co-cultured with HOXA11 over-expressed GC cells, counterparts or alone, cytokine array analyses of serum-free culture medium of HOXA11 over-expressed GC cells, we validated our findings through genetic manipulation of HMrSV5 cells and neutralizing antibodies targeting cytokines secreted by HOXA11 over-expressed GC cells in vitro, as well as utilized human peritoneal metastatic lesions to validate expression of potential targets. We identified that HOXA11 over-expressed GC cells strongly propelled mesothelial fibrosis in vivo and in vitro, and HOXA11 regulated paracrine and autocrine of PDGF BB and TGF β1 in GC cells to propel mesothelial fibrosis. Meanwhile, HOXA11 over-expressed GC cells drove PDGF BB and TGF β1 secretion to activate developmental-process related genes in HMrSV5 cells, including Egr1, which processes dependent on miR-181a-5p. Then, Egr1 could mediate peritoneal mesothelial fibrosis. Correspondingly, Egr1 over-expressed HMrSV5 cells supported migration and peritoneal dissemination of GC cells. Together our results suggest that a feedforward amplifier circuity governing GC cells and mesothelial cells in peritoneum contribute to peritoneal metastasis of GC cells.

The role of microRNAs in pathophysiology and diagnostics of metabolic complications in obstructive sleep apnea patients

Obstructive sleep apnea (OSA) is one of the most common sleep disorders, which is characterized by recurrent apneas and/or hypopneas occurring during sleep due to upper airway obstruction. Among a variety of health consequences, OSA patients are particularly susceptible to developing metabolic complications, such as metabolic syndrome and diabetes mellitus type 2. MicroRNAs (miRNAs) as epigenetic modulators are promising particles in both understanding the pathophysiology of OSA and the prediction of OSA complications. This review describes the role of miRNAs in the development of OSA-associated metabolic complications. Moreover, it summarizes the usefulness of miRNAs as biomarkers in predicting the aforementioned OSA complications.

Capturing the Kidney Transcriptome by Urinary Extracellular Vesicles-From Pre-Analytical Obstacles to Biomarker Research

Urinary extracellular vesicles (uEV) hold non-invasive RNA biomarkers for genitourinary tract diseases. However, missing knowledge about reference genes and effects of preanalytical choices hinder biomarker studies. We aimed to assess how preanalytical variables (urine storage temperature, isolation workflow) affect diabetic kidney disease (DKD)-linked miRNAs or kidney-linked miRNAs and mRNAs (kidney-RNAs) in uEV isolates and to discover stable reference mRNAs across diverse uEV datasets. We studied nine raw and normalized sequencing datasets including healthy controls and individuals with prostate cancer or type 1 diabetes with or without albuminuria. We focused on kidney-RNAs reviewing literature for DKD-linked miRNAs from kidney tissue, cell culture and uEV/urine experiments. RNAs were analyzed by expression heatmaps, hierarchical clustering and selecting stable mRNAs with normalized counts (>200) and minimal coefficient of variation. Kidney-RNAs were decreased after urine storage at -20 °C vs. -80 °C. Isolation workflows captured kidney-RNAs with different efficiencies. Ultracentrifugation captured DKD -linked miRNAs that separated healthy and diabetic macroalbuminuria groups. Eleven mRNAs were stably expressed across the datasets. Hence, pre-analytical choices had variable effects on kidney-RNAs-analyzing kidney-RNAs complemented global correlation, which could fade differences in some relevant RNAs. Replicating prior DKD-marker results and discovery of candidate reference mRNAs encourages further uEV biomarker studies.

Early growth response factor 1 upregulates pro-fibrotic genes through activation of TGF-β1/Smad pathway via transcriptional regulation of PAR1 in high-glucose treated HK-2 cells

Tubulointerstitial fibrosis (TIF) makes a key role in diabetic kidney disease (DKD). In this study, we revealed that the expressions of Egr1 and protease-activated receptor 1 (PAR1) were increased in renal tissues of DKD rats. In vitro experiments demonstrated that both Egr1 overexpression and high glucose (HG) condition could promote the expressions of PAR1, fibronectin (FN) and collagen I (COL I). Furthermore, HG stimulation enhanced the binding capacity of Egr1 to PAR1 promoter. Both HG condition and Egr1 upregulation could increase, and thrombin inhibitor did not affect activity of TGF-β1/Smad pathway via PAR1. Collectively, Egr1 is involved in TIF of DKD partly through activating TGF-β1/Smad pathway via transcriptional regulation of PAR1 in HG treated HK-2 cells.

Jiedu Tongluo Baoshen formula enhances renal tubular epithelial cell autophagy to prevent renal fibrosis by activating SIRT1/LKB1/AMPK pathway

Renal fibrosis, an important pathological change in the development of diabetic kidney disease (DKD), urgently needs new treatment methods clinically. The Jiedu Tongluo Baoshen (JTBF) formula was created based on the theory of toxic damage to the kidney collaterals, and a variety of active ingredients in JTBF have inhibitory effects on epithelial-mesenchymal transition (EMT) and extracellular matrix (ECM). In this study, the Ultra Performance Liquid Chromatography (UPLC) was employed to analyze the effective ingredients in the JTBF formula. After screening in the PubChem database, we identified 94 active compounds of JTBF and predicted the SIRT1 pathway as potential targets through network pharmacology. In addition, in the high fat diet (HFD)+Streptozocin (STZ)-induced DKD rat model and high glucose (HG)-induced NRK-52E cell model, JTBF treatment activates the phosphorylation of LKB1 and AMPK and enhances the autophagy activity of NRK-52E cells, thereby reducing the accumulation of EMT and ECM. These results have been confirmed in vivo and in vitro experiments. JTBF enhances the autophagy activity of renal tubular epithelial cells and inhibits the progression of DKD renal fibrosis by activating the SIRT1/LKB1/AMPK signal pathway. This study provides new insights into the molecular mechanism of JTBF to prevent and treat DKD renal fibrosis.

Urinary microRNA in Diabetic Kidney Disease: A Literature Review

Diabetic kidney disease is the most common primary disease of end-stage kidney disease globally; however, a sensitive and accurate biomarker to predict this disease remains awaited. microRNAs are endogenous single-stranded noncoding RNAs that have intervened in different post-transcriptional regulations of various cellular biological functions. Previous literatures have reported its potential role in the pathophysiology of diabetic kidney disease, including regulation of Transforming Growth Factor-β1-mediated fibrosis, extracellular matrix and cell adhesion proteins, cellular hypertrophy, growth factor, cytokine production, and redox system activation. Urinary microRNAs have emerged as a novel, non-invasive liquid biopsy for disease diagnosis. In this review, we describe the available experimental and clinical evidence of urinary microRNA in the context of diabetic kidney disease and discuss the future application of microRNA in routine practice.

Integrated analysis of mRNA-seq and miRNA-seq reveals the potential roles of Egr1, Rxra and Max in kidney stone disease

Nephrolithiasis is one of the most common and frequent urologic diseases worldwide. The molecular mechanism of kidney stone formation is complex and remains to be illustrated. Transcript factors (TFs) that influenced the expression pattern of multiple genes, as well as microRNAs, important posttranscriptional modulators, play vital roles in this disease progression. Datasets of nephrolithiasis mice and kidney stone patients were acquired from Gene Expression Omnibus repository. TFs were predicted from differentially expressed genes by RcisTarget. The target genes of differential-expressed microRNAs were predicted by miRWalk. MicroRNA-mRNA network and PPI network were constructed. Functional enrichment analysis was performed via Metascape and Cytoscape identified hub genes. The assay of quantitative real-time PCR (q-PCR) and immunochemistry and the datasets of oxalate diet-induced nephrolithiasis mice kidneys and kidney stone patients' samples were utilized to validate the bioinformatic results. We identified three potential key TFs (Egr1, Rxra, Max), which can be modulated by miR-181a-5p, miR-7b-3p and miR-22-3p, respectively. The TFs and their regulated hub genes influenced the progression of nephrolithiasis via altering the expression of genes enriched in the functions of fibrosis, cell proliferation and molecular transportation and metabolism. The expression changes of transcription factors were consistent in q-PCR and immunochemistry results. For regulated hub genes, they showed consistent expression changes in oxalate diet-induced nephrolithiasis mice model and human kidneys with stones. The identified and verified three TFs, which may be modulated by microRNAs in nephrolithiasis disease progression, mainly influence biological processes responding to fibrosis, proliferation and molecular transportation and metabolism. The transcript influence showed consistency in multiple nephrolithiasis mice models and kidney stone patients.

Analysis of exosome-derived microRNAs as early biomarkers of lipopolysaccharide-induced acute kidney injury in rats

Sepsis contributes to the high prevalence of acute kidney injury (AKI), which mainly occurs in hospitalized patients. The delay in AKI detection is a risk factor for death and chronicity; thus, early diagnosis is essential for initiating proper treatment strategies. Although serum creatinine is used as biomarker, it is increased in plasma serum creatinine only at late stages of AKI. MicroRNAs (miRNAs), a class of noncoding RNAs responsible for gene regulation, can be found in biological fluids within vesicles such as exosomes and may be promising tools for the early detection of AKI. We aimed to identify potential blood miRNAs that can be used as early biomarkers of sepsis-induced AKI in rats. Adult male Wistar rats received a single dose of lipopolysaccharide (LPS). The earliest significant increase in serum creatinine was detected 4 h after LPS administration. To evaluate whether miRNAs could act as early biomarkers, blood samples were collected before and 2 h after LPS infusion. Serum NGAL levels were used as a comparative marker. Serum miRNAs were derived from exosomes, and their expression were evaluated by the PCR array. miR-181a-5p and miR-23b-3p showed higher expression in LPS-treated rats than in the control animals (p < 0.05). Bioinformatics analysis showed that both miRNAs target molecules associated with transcription factors that regulate genes related to proinflammatory cytokines. Considering that LPS activates transcription factors that lead to the production of proinflammatory cytokines, possible premature changes in the serum levels of miR-181a-5p and miR-23b-3p may be used to identify sepsis-induced AKI earlier.

Fucoidan-Mediated Inhibition of Fibrotic Properties in Oral Submucous Fibrosis via the MEG3/miR-181a/Egr1 Axis

Oral submucous fibrosis (OSF) is a chronic fibrotic remodeling disease that can progress to oral cancer. However, efficient clinical diagnosis and treatment methods for OSF are still lacking. This study investigated the anti-fibrotic effect of fucoidan on oral fibrosis. To evaluate the fibrotic ability (myofibroblast activities), we performed wound-healing, Transwell migration, and collagen contraction assays by using patient-derived normal and fibrotic buccal submucous fibroblasts (BMFs and fBMFs, respectively). RNA-sequencing and dual-luciferase reporter and RNA immunoprecipitation chip assays were performed to identify the clinical significance and molecular mechanism of non-coding RNAs. Fucoidan suppressed the myofibroblast activities and inhibited the MEG3 in fBMFs. MEG3 was overexpressed in the OSF tissue and was positively associated with myofibroblast markers. Knockdown of MEG3 markedly inhibited myofibroblast activities, which were restored by inhibiting miR-181a and overexpressing Egr1. The results from luciferase reporter and RIP assays confirmed that MEG3 functioned as a competing endogenous RNA (ceRNA) and could directly target miR-181a, thereby preventing the miR-181a-mediated translational repression of Egr1. This study demonstrated that MEG3 exerts a profibrotic effect on OSF by targeting miR-181a/Egr1. Therefore, the administration of fucoidan may serve as a potential therapeutic strategy for OSF by targeting the overexpression of MEG3.

Long noncoding RNA XIST regulates brown preadipocytes differentiation and combats high-fat diet induced obesity by targeting C/EBPα

BACKGROUND

Activation of brown adipose tissue (BAT) increases energy expenditure, which makes it an attractive therapeutic strategy for obesity. LncRNAs play an important role in adipocyte differentiation and regulation. Here we assessed the effect of lncRNA XIST on brown preadipocytes differentiation and metabolic regulation.

METHODS

XIST expression levels were detected in human perirenal (peri-N) and subcutaneous adipose tissues (sub-Q), brown preadipocytes and 3T3-L1 preadipocytes. XIST overexpression and knockdown experiments were performed in brown preadipocytes. XIST overexpression mouse model was established by plasmid injection through tail vein.

RESULTS

In human adipose tissues, XIST expression was significantly higher in female than in male individuals. In vitro, XIST expression was significantly up-regulated during brown adipocyte differentiation. XIST knockdown inhibited differentiation of brown preadipocytes, while overexpression of XIST promotes brown preadipocytes to fully differentiation. RNA Binding Protein Immunoprecipitation (RIP) experiment revealed that XIST could directly bind to C/EBPα. In vivo, XIST overexpression prevents high-fat diet induced obesity and improves metabolic dysorder in male mice.

CONCLUSION

Our results suggest that XIST combats obesity through BAT activation at least partly by combination with transcription factor C/EBPα.

Brown adipose tissue transplantation ameliorates diabetic nephropathy through the miR-30b pathway by targeting Runx1

OBJECTIVE

Adipose tissue is a major source of circulating microRNAs (miRNAs) that can regulate target genes in distant organs. However, the role of brown adipose tissue (BAT) in diabetic kidney disease (DKD) is still unknown. We studied the original BAT miR-30b targeting two key fibrotic regulators, Runt-related transcription factor 1 (Runx1) and snail family zinc finger 1 (Snail1), to combat DKD.

METHODS

First, we transplanted healthy BAT from normal mouse donors into diabetic mice (induced by a high-fat diet and streptozotocin injection). In vitro, we observed extracellular vesicles (EVs) secreted from brown adipocytes. AgomiR-30b was directly administered to the BAT of diabetic mice twice weekly for 4 consecutive weeks. Next, the role of Runx1 in DKD was determined by using siRUNX1 or pCMV-RUNX1 in HK-2 cells and in diabetic mice treated with AAV9-U6-shRunx1 or AAV9-EF1a-Runx1.

RESULTS

BAT transplantation reactivated endogenous BAT activity in diabetic mice, increased circulating miR-30b levels and significantly ameliorated DKD. In TGFβ1-treated HK-2 cells, miR-30b expression was significantly suppressed. miR-30b overexpression markedly decreased fibronectin and downregulated Runx1 and Snail1 expression, while silencing of miR-30b had the opposite effects. Next, Runx1 knockdown and overexpression mimicked the above phenotype of miR-30b mimics and inhibitors, respectively, both in vitro and in vivo. Moreover, Runx1 promoted TGFβ1-induced fibrosis by upregulating the PI3K pathway.

CONCLUSION

BAT-derived miRNAs might be a promising target for kidney protection in diabetes mellitus.

miR-23a-3p regulates the inflammatory response and fibrosis in diabetic kidney disease by targeting early growth response 1

Diabetic kidney disease (DKD) has become the most common cause of chronic kidney disease. Proteinuria is generally considered one of the clinical indicators of renal damage, and it is also closely related to the progression of DKD. Accumulating evidence indicates that proteinuria induces an upregulation of the expression levels of inflammatory cytokines and fibrosis markers in renal tubular epithelial cells, but the mechanism remains unclear. Previously, we showed that early growth response 1 (Egr1) played a key role in renal tubular injury. However, the upstream mechanism of Egr1 in the development of DKD is poorly understood. In this study, we found that albumin stimulation significantly increased the expression levels of Egr1, interleukin 6 (IL-6), tumor necrosis factor-α (TNF-α), and fibronectin (FN) in HK-2 cells but decreased miR-23a-3p levels. We then identified that miR-23a-3p targeted the 3′ untranslated region (UTR) of Egr1 and directly suppressed the expression of Egr1. Moreover, we found that overexpression and inhibition of miR-23a-3p in HK-2 cells attenuated and promoted the expression of IL-6, TNF-α, and FN, respectively. Additionally, Egr1 silencing reversed the inflammation and fibrosis caused by the miR-23a-3p inhibitor. Thus, we conclude that miR-23a-3p attenuates the development of DKD through Egr1, suggesting that targeting miR-23a-3p may be a novel therapeutic approach for DKD.

MicroRNAs in organ fibrosis: From molecular mechanisms to potential therapeutic targets

Fibrosis is caused by chronic tissue injury and characterized by the excessive deposition of extracellular matrix (ECM) that ultimately results in organ failure and death. Owing to lacking of effective treatment against tissue fibrosis, it causes a high morbidity and mortality worldwide. Thus, it is of great importance to find an effective therapy strategy for the treatment of fibrosis. MicroRNAs (miRNAs) play vital roles in many biological processes by targeting downstream genes. Numerous studies demonstrated that miRNAs served as biomarkers of various diseases, suggesting the potential therapeutic targets for diseases. It was recently reported that miRNAs played an important role in the development of organ fibrosis, which showed a promising prospect against fibrosis by targeting intervention. Here, we summarize the roles of miRNAs in the process of organ fibrosis, including liver, lung, heart and kidney, and highlight miRNAs being novel therapeutic targets for organ fibrosis.

CIDEC silencing attenuates diabetic nephropathy via inhibiting apoptosis and promoting autophagy

OBJECTIVE

The role of cell death-inducing DFF45-like effector C (CIDEC) in insulin resistance has been established, and it is considered to be an important trigger factor for the progression of diabetic nephropathy (DN). We intend to explore whether CIDEC plays an important role in the regulation of DN and its potential mechanism.

METHODS

High-fat diet and low dose streptozotocin were used to establish type 2 diabetic rat model. We investigate the role of CIDEC in the pathogenesis and process of DN through histopathological analysis, western blot and gene silencing. Meanwhile, the effect of CIDEC on renal tubular epithelial cells stimulated by high glucose was also verified.

RESULTS

DM group exhibited glucose and lipid metabolic disturbance, with hypertrophy of kidneys, damaged renal function, increased apoptosis, decreased autophagy, glomerulosclerosis and interstitial fibrosis. CIDEC gene silencing improved metabolic disorder and insulin resistance, alleviated renal hypertrophy and renal function damage, decreased glomerular and tubular apoptosis, increased autophagy and inhibited renal fibrosis. At the cellular level, high glucose stimulation increased CIDEC expression in renal tubular epithelial cells, accompanied by increased apoptosis and decreased autophagy. CIDEC gene silencing can improve autophagy and reduce apoptosis. At the molecular level, CIDEC gene silencing also decreased the expression of early growth response factor (EGR)1 and increased the expression of adipose triglyceride lipase (ATGL).

CONCLUSION

CIDEC gene silencing may delay the progression of DN by restoring autophagy activity and inhibiting apoptosis with the participation of EGR1and ATGL.

Klotho prevents epithelial-mesenchymal transition through Egr-1 downregulation in diabetic kidney disease

INTRODUCTION

As a key event leading to tubulointerstitial fibrosis in diabetic kidney disease (DKD), epithelial-mesenchymal transition (EMT) has drawn increasing attention from researchers. The antiaging protein Klotho attenuates renal fibrosis in part by inhibiting ERK1/2 signaling in DKD. Early growth response factor 1 (Egr-1), which is activated mainly by ERK1/2, has been shown to play an important role in EMT. However, whether Klotho prevents EMT by inhibiting ERK1/2-dependent Egr-1 expression in DKD is unclear.The aim of this study was to investigate whether Klotho prevents EMT through Egr-1 downregulation by inhibiting the ERK1/2 signaling pathway in DKD.

RESEARCH DESIGN AND METHODS

Male C57BL/6J mice fed an high-fat diet for 4 weeks received 120 mg/kg streptozotocin (STZ), which was injected intraperitoneally. Klotho and Egr-1 expression was detected in the renal cortices of these mice on their sacrifice at 6 and 12 weeks after STZ treatment. In In vitro studies, we incubated HK2 cells under high-glucose (HG) or transforming growth factor-β1 (TGF-β1) conditions to mimic DKD. We then transfected the cells with an Klotho-containing plasmid, Klotho small interfering RNA.

RESULTS

Klotho expression was significantly decreased in the renal cortices of mice with diabetes mellitus (DM) compared with the renal cortices of control mice at 6 weeks after treatment and even more significantly decreased at 12 weeks. In contrast, Egr-1 expression was significantly increased in mice with DM compared with control mice only at 12 weeks. We also found that Klotho overexpression downregulated Egr-1 expression and the (p-ERK1/2):(ERK1/2) ratio in HG-treated or TGF-β1-treated HK2 cells. Conversely, Klotho silencing upregulated Egr-1 expression and the (p-ERK1/2):(ERK1/2) ratio in HG-treated or TGF-β1-treated HK2 cells. Moreover, the effects of si-Klotho were abolished by the ERK1/2 inhibitor PD98059.

CONCLUSIONS

Klotho prevents EMT during DKD progression, an effect that has been partially attributed to Egr-1 downregulation mediated by ERK1/2 signaling pathway inhibition.

Update on the Mechanisms of Tubular Cell Injury in Diabetic Kidney Disease

Increasing evidence supports a role of proximal tubular (PT) injury in the progression of diabetic kidney disease (DKD), in patients with or without proteinuria. Research on the mechanisms of the PT injury in DKD could help us to identify potential new biomarkers and drug targets for DKD. A high glucose transport state and mismatched local hypoxia in the PT of diabetes patients may be the initiating factors causing PT injury. Other mechanism such as mitochondrial dysfunction, reactive oxygen species (ROS) overproduction, ER stress, and deficiency of autophagy interact with each other leading to more PT injury by forming a vicious circle. PT injury eventually leads to the development of tubulointerstitial inflammation and fibrosis in DKD. Many downstream signaling pathways have been demonstrated to mediate these diseased processes. This review focuses mostly on the novel mechanisms of proximal renal tubular injury in DKD and we believe such review could help us to better understand the pathogenesis of DKD and identify potential new therapies for this disease.

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.

LncRNA PVT1 Suppresses the Progression of Renal Fibrosis via Inactivation of TGF-β Signaling Pathway

BACKGROUND

Renal fibrosis is a frequent pathway leading to end-stage kidney dysfunction. In addition, renal fibrosis is the ultimate manifestation of chronic kidney diseases (CKD). Long noncoding RNAs (lncRNAs) are known to be involved in occurrence of renal fibrosis, and lncRNA plasmacytoma variant translocation 1 (PVT1) has been reported to act as a key biomarker in renal diseases. However, the role of PVT1 in renal fibrosis remains unclear.

MATERIALS AND METHODS

HK-2 cells were treated with TGF-β1 to mimic renal fibrosis in vitro. Gene and protein expressions in HK-2 cells were measured by qRT-PCR and Western-blot, respectively. ELISA was used to test the level of creatinine (CR) and blood urea nitrogen (BUN) in serum of mice. Additionally, unilateral ureteral obstruction (UUO)-induced renal fibrosis mice model was established to investigate the effect of PVT1 on renal fibrosis in vivo.

RESULTS

PVT1 was upregulated in TGF-β1-treated HK-2 cells. In addition, TGF-β1-induced upregulation of α-SMA and fibronectin in HK-2 cells was significantly reversed by PVT1 knockdown. Meanwhile, PVT1 bound to miR-181a-5p in HK-2 cells. Moreover, miR-181a-5p directly targeted TGF-βR1. Furthermore, miR-181a-5p antagonist could significantly reverse the anti-fibrotic effect of PVT1 knockdown. Besides, knockdown of PVT1 notably attenuated the symptom of renal fibrosis in vivo.

CONCLUSION

Knockdown of PVT1 significantly inhibited the progression of renal fibrosis in vitro and in vivo. Thus, PVT1 may serve as a potential target for the treatment of renal fibrosis.

Silencing of lncRNA PVT1 ameliorates streptozotocin-induced pancreatic β cell injury and enhances insulin secretory capacity by regulating miR-181a-5p

Diabetes mellitus (DM) is a type of metabolic disorder characterized by long-term hyperglycemia. Accumulating evidence shows that long noncoding RNAs (lncRNAs) play significant roles in the occurrence and development of DM. This study intended to investigate the role of lncRNA plasmacytoma variant translocation 1 (PVT1) in rat insulinoma (INS-1) cells damaged by streptozotocin (STZ) and to identify the potential mechanisms. Firstly, PVT1 expression in INS-1 cells was assessed using RT-qPCR after STZ stimulation. After PVT1-knockdown, cell apoptosis, the contents of oxidative stress related markers, and changes in insulin secretion were detected. Results indicated that PVT1 was remarkably upregulated after STZ stimulation. PVT1-knockdown inhibited STZ-induced oxidative stress and apoptosis of INS-1 cells. Moreover, the insulin secretory capacity was notably elevated following PVT1 silencing. Subsequently, a luciferase reporter assay verified that miR-181a-5p was directly targeted by PVT1. The rescue assays revealed that miR-181a-5p inhibitor dramatically abrogated the effects of PVT1 silencing on oxidative stress, apoptosis, and insulin secretion. Taken together, these findings demonstrated that PVT1-knockdown could ameliorate STZ-induced oxidative stress and apoptosis and elevate insulin secretory capacity in pancreatic β cells by regulating miR-181a-5p, suggesting a promising biomarker in DM diagnosis and treatment.

Long non-coding RNA MEG3 promotes fibrosis and inflammatory response in diabetic nephropathy via miR-181a/Egr-1/TLR4 axis

Long non-coding RNAs (lncRNAs) play vital roles in diabetic nephropathy (DN). This research aimed to study the potential role and underlying molecular mechanisms of long non-coding RNA MEG3 in DN. We found that MEG3 was upregulated in DN in vivo and in vitro and could enhance cell fibrosis and inflammatory response in DN. MEG3 functioned as an endogenous sponge for miR-181a in mesangial cells (MCs) via direct targeting and in an Ago2-dependent manner. MiR-181a inhibition promoted MC fibrosis and inflammatory response. In addition, Egr-1 was confirmed as a target gene of miR-181a. Further investigations verified that MEG3 promotes fibrosis and inflammatory response via the miR-181a/Egr-1/TLR4 axis in vitro and in vivo. These results provide new insights into the regulation between MEG3 and the miR-181a/Egr-1/TLR4 signaling pathway during DN progression.

miR-181a-5p regulates the proliferation and apoptosis of glomerular mesangial cells by targeting KLF6

Diabetic nephropathy (DN) is a chronic loss of kidney function that frequently occurs in patients with diabetes mellitus and is characterized by abnormal glomerular mesangial cell (GMC) proliferation and apoptosis. By using microarray analysis, microRNA (miR)-181a-5p has previously been identified to be dysregulated in DN. The present study aimed to determine the underlying molecular mechanisms and function of miR-181a-5p in GMCs under DN conditions. First, reverse transcription-quantitative PCR was performed to detect miR-181a-5p and kruppel-like factor 6 (KLF6) expression in GMCs following high-glucose treatment. Subsequently, MTT and flow cytometric assays were performed in order to determine the effect of miR-181a-5p and KLF6 on high-glucose-driven GMC proliferation and apoptosis. After confirming that KLF6 was a target gene of miR-181a-5p via a bioinformatics analysis and luciferase reporter assay, the mRNA and protein expression levels of associated factors in different treatment groups were measured. The results demonstrated that miR-181a-5p was significantly downregulated, while KLF6 was significantly upregulated in GMCs following treatment with high glucose. Furthermore, overexpression of miR-181a led to suppression of cell proliferation and promoted apoptosis of GMCs induced by high glucose, while these effects were inhibited by co-transfection with KLF6. Finally, miR-181-5p was demonstrated to inhibit the expression of KLF6, Bcl-2, Wnt1 and β-catenin, while increasing the expression levels of Bax and caspase-3. In conclusion, the expression levels of miR-181a-5p were downregulated in GMCs following treatment with high glucose and overexpression of miR-181a-5p may inhibit GMC proliferation and promote apoptosis, at least partially through targeting KLF6 via the Wnt/β-catenin signaling pathway. Overall, the results of the present study suggest that miR-181a-5p may have a crucial role in the occurrence and development of DN and may be a valuable diagnostic marker and therapeutic target for DN.

Long noncoding RNA NEAT1 is involved in the protective effect of Klotho on renal tubular epithelial cells in diabetic kidney disease through the ERK1/2 signaling pathway

Klotho, an antiaging protein, has been shown to play a protective role in renal tubular epithelial-mesenchymal transition (EMT) during the development of diabetic kidney disease (DKD). Long noncoding RNAs (lncRNAs) participate in the progression of EMT in many diseases. However, the effect of Klotho on lncRNAs during the development of DKD is still unknown. In this study, we found that Klotho overexpression in high-fat diet (HFD)- and streptozotocin (STZ)-induced DKD mice significantly inhibited the expression of lncRNA nuclear-enriched abundant transcript 1 (Neat1). We demonstrated that NEAT1 was significantly upregulated in both bovine serum albumin (BSA)-stimulated HK2 cells and mice with HFD- and STZ-induced diabetes. In addition, we observed that Klotho displays colocalization with NEAT1. Furthermore, overexpression of Klotho can inhibit the high expression of NEAT1 in BSA-stimulated HK2 cells, while silencing Klotho can further upregulate the expression of NEAT1. Silencing NEAT1 in HK2 cells resulted in inhibition of the EMT-related markers alpha smooth muscle actin (α-SMA) and vimentin (VIM) and the renal fibrosis-related markers transforming growth factor-β1 (TGF-β1) and connective tissue growth factor (CTGF). The effect of NEAT1 on DKD was partly mediated by regulation of the ERK1/2 signaling pathway. Finally, we found that silencing NEAT1 can reverse the activation of EMT and fibrosis caused by Klotho silencing in a manner dependent on the ERK1/2 signaling pathway. These findings reveal a new regulatory pathway by which Klotho regulates ERK1/2 signaling via NEAT1 to protect against EMT and renal fibrosis, suggesting that NEAT1 is a potential therapeutic target for DKD.

An anti-ageing protein called Klotho helps protect against kidney failure in mice and human cells by silencing a long non-coding RNA molecule. The regulatory RNA involved, known as NEAT1, promotes cellular transformations associated with the disease process. A team led by Yao-Ming Xue from Southern Medical University in Guangdong, China, showed that levels of NEAT1 are elevated in mouse models of diabetic kidney disease and in injured human kidney calls. The identification of NEAT1 in kidney disease thus provides a novel therapeutic target. After demonstrating that Klotho and NEAT1 interact directly with each other in cells, they experimentally boosted Klotho expression and observed suppressed levels of NEAT1. As a consequence, the cells displayed lower levels of the proteins linked to the progressive deposition of fibrosis in the kidneys.

Comprehensive Analysis of Differentially Expressed miRNAs and mRNAs Reveals That miR-181a-5p Plays a Key Role in Diabetic Dermal Fibroblasts

A diabetic nonhealing wound causes heavy economic burden and compromised quality of life in patients. The human dermal fibroblast (HDF), which is an important kind of effector cell in the wound healing process, represents different biological behaviors in the normal and diabetic skins. Given this, we attempt to explore functional changes in diabetic skin-derived HDFs and try to find out the "hub" genes that modulate diabetic HDFs and may be the potential therapeutic targets of diabetic wound healing. We searched the GEO database for related miRNA (GSE68185, GSE84971) and mRNA (GSE49566, GSE78891) profiles. After eliminating batch effects and identifying differentially expressed genes (DEGs), we applied enrichment analyses and found that 3 miRNAs and 30 mRNAs were differentially expressed in diabetic HDFs. Enrichment analyses showed that these genes are closely related to wound healing, for example, extracellular matrix (ECM) organization, angiogenesis, cell proliferation, and migration. Subsequently, we constructed the gene correlation network of DEGs to identify hub genes by merging the protein-protein interaction network, weighted gene coexpression network, and predicted miRNA-mRNA regulatory network. Based on the gene correlation network, we identified the top 3 hub genes: miR-181a-5p, POSTN, and CDH11. Among these, POSTN is a predicted target of miR-181a-5p and is supposed to work together with CDH11 as a functional group. Finally, we verified the expression pattern of the hub genes by in vitro quantification experiments in glucose-cultured HDFs. Our study suggested that miR-181a-5p possibly plays a key role in modulation of HDF behaviors during the diabetic state. However, the effects and mechanisms of miR-181a-5p in high glucose-cultured HDFs remain to be explored in the future.

Egr1 Knockdown Combined with an ACE Inhibitor Ameliorates Diabetic Kidney Disease in Mice: Blockade of Compensatory Renin Increase

BACKGROUND

Increased compensatory intrarenal renin diminishes the efficacy of angiotensin-converting enzyme inhibitors (ACEIs) and angiotensin receptor blockers (ARBs) in the treatment of diabetic kidney disease (DKD). Early growth response-1 (Egr1) is a crucial transcriptional factor in the progress of DKD and is a potential transcription factor of intrarenal renin according to bioinformatic analysis. However, whether inhibition of Egr1 can suppress compensatory renin increase in DKD is unclear.

METHODS

We generated a high-fat diet (HFD)/streptozotocin (STZ)-induced diabetic mouse model. The mice were treated with either enalapril (an ACEI) or enalapril combined with a shEgr1 plasmid, and age-matched DKD mice were used as controls. Urine microalbumin, urinary renin and kidney TGF-β1 were determined by enzyme-linked immunosorbent assay (ELISA). Hematoxylin and eosin (H&E) and Masson staining were used to determine renal pathological changes. Egr1, renin, TNF-α, and FN were measured by real-time quantitative PCR, Western blot, and immunohistochemistry. The SV40-MES13 murine mesangial cell line was transfected with pENTER-Egr1 plasmid and siEgr1.

RESULTS

Our results showed that enalapril increased the renin level of urinary and renal in DKD mice, while shEgr1 attenuated this effect. In addition, enalapril treatment reduced the levels of urinary microalbumin, TNF-α, TGF-β1 and FN, and alleviated the pathological changes, while shEgr1 strengthened these effects. The protein and mRNA expression of renin in the SV40 MES13 cells was upregulated and downregulated following overexpression and silence of Egr1, respectively.

CONCLUSION

Silence of Egr1 could alleviate renal injury in DKD by downregulating intrarenal renin.

Renoprotective effects of brown adipose tissue activation in diabetic mice

BACKGROUND

Brown adipose tissue (BAT) has been regarded as a potential target organ to combat obesity and related metabolic disorders. However, the effect of BAT activation on the development of diabetic kidney disease (DKD) remains unclear.

METHODS

Diabetic mice were induced by streptozotocin (STZ) combined with a high-fat diet. To activate BAT, mice were administered 1 mg/kg per day, i.p., CL316,243, a β₃ -adrenergic receptor agonist, for 4 weeks. Blood glucose, serum lipids, adipokines, 24-hour urinary albumin, 8-hydroxydeoxyguanosine (8-OHdG), and circulating microRNA (miRNA) levels were analyzed, in addition to renal pathology. Histological changes (fibrosis, inflammation) were evaluated in the kidneys, as was the expression of oxidative stress-related genes. Renal signaling pathways (fibroblast growth factor [Fgf]21/β-klotho/FGF receptor 1c and AMP-activated protein kinase[AMPK]/sirtuin 1 [Sirt1]/peroxisome proliferator-activated receptor-γ coactivator-1α [Pgc1α]) were also evaluated.

RESULTS

Compared with untreated STZ-diabetic mice, CL316,243 treatment reduced blood glucose, albeit not significantly (20.58 ± 3.55 vs 23.60 ± 3.90 mM), and significantly decreased triglycerides and low-density lipoprotein cholesterol and increased high-density lipoprotein cholesterol. Simultaneously, BAT activation significantly decreased 24-hour urinary albumin (34.21 ± 6.28 vs 70.46 ± 15.81 μg/24 h; P < 0.05) and 8-OHdG, improved renal fibrosis, inflammation, and oxidative stress, and ameliorated renal morphological abnormalities. In addition to enhancing BAT activity, CL316,243 significantly increased serum adiponectin concentrations and renal Fgf21 sensitivity, and reactivated the renal AMPK/Sirt1/Pgc1α signaling pathway. Furthermore, CL316,243 treatment increased levels of some circulating miRNAs and downregulated expression of their target genes in the kidney.

CONCLUSIONS

Activating BAT could improve kidney injury in diabetic mice via metabolic improvements and renal AMPK activation by beneficial adipokines and miRNAs.

LncRNA GAS5 exacerbates renal tubular epithelial fibrosis by acting as a competing endogenous RNA of miR-96-5p

Renal fibrosis is at the core of various renal diseases, including diabetic kidney disease (DKD). Long noncoding RNAs (lncRNAs) are known players in the regulation of renal fibrosis. However, their expression and function in DKD still need to be elucidated. The purpose of this study was to assess how lncRNA GAS5 regulates fibrosis and its mechanism in TGF-β1-treated renal proximal tubular cell.In this study, the lncRNA GAS5 was upregulated in both TGF-β1-treated HK-2 cells and the kidneys of HDF/STZ mice. Knockdown of GAS5 relieved renal tubular epithelial fibrosis. This effect was mediated by the downregulation and functional inactivation of miR-96-5p. Furthermore, miR-96-5p was downregulated in DKD mice, and this downregulation attenuated the repression of FN1(fibronectin, FN) and led to its upregulation. The decrease in miR-96-5p was partially attributed to the miRNA-sponge action of GAS5.Our research demonstrates that knockdown of lncRNA GAS5 leads to antifibrosis by competitively binding miR-96-5p, which inhibits the expression of FN1. These results indicate that targeting lncRNA GAS5 may be a promising therapeutic strategy for preventing DKD.

Hypermethylated long noncoding RNA MEG3 promotes the progression of gastric cancer

This study aims to explore the expression and degree of methylation of lncRNA MEG3 in gastric cancer tissues and to analyze its effect on the migration and proliferation of gastric cancer patients and the mechanism by which this occurs. The targeting relationship between MEG3, miR-181a-5p and ATP4B was detected through molecular biology experiments. Wound healing, transwell, colony formation and flow cytometry assays were used to analyze the effects of lncRNA MEG3 and methylation on tumor cell migration, invasion, proliferation and apoptosis. In addition, a tumor xenotransplantation model was established to study the influence of MEG3 on tumor growth in vivo. Bioinformatics analysis showed that lncRNA MEG3 and ATP4B were downregulated in gastric cancer tissues compared with normal tissues. Bioinformatics predicted that ATP4B might be regulated by targeting miR-181a-5p. The overexpression of MEG3 and the application of 5-Aza treatment inhibited the migration, invasion and proliferation of MGC-803 cells and promoted apoptosis. In gastric cancer tissues, MEG3 is hypermethylated to decrease expression. Once the expression of MEG3 is restored or methylation is inhibited, tumor growth can be inhibited both in vivo and in vitro. This finding could be utilized as a clinical reference for gastric cancer treatment in the future.

Emerging role of miRNAs in renal fibrosis

As one type of the most common endogenous short noncoding RNAs (ncRNAs), microRNAs (miRNAs) act as posttranscriptional regulators of gene expression and have great potential biological functions in the physiological and pathological processes of various diseases. The role of miRNAs in renal fibrosis has also attracted great attention in the previous 20 years, and new therapeutic strategies targeting miRNAs appear to be promising. Some researchers have previously reviewed the roles of miRNA in renal fibrosis disease, but numerous studies have emerged over the recent 5 years. It is necessary to update and summarize research progress in miRNAs in renal fibrosis. Thus, in this review, we summarize progress in miRNA-mediated renal fibrosis over the last 5 years and evaluate the biological functions of some miRNAs in different stages of renal fibrosis. Furthermore, we also expound the recent clinical applications of these miRNAs to provide new insights into the treatment of renal fibrosis disease.

MicroRNA-181a exerts anti-inflammatory effects via inhibition of the ERK pathway in mice with intervertebral disc degeneration

Enzymatic decomposition of extracellular matrix and possibly local inflammation may cause intervertebral disc degeneration (IDD). MicroRNAs have been reported to correlate with the development of IDD. In this experiment, we aim at finding out the role of miR-181a in the inflammation of IDD and the underlying mechanism. The targeting relationship between miR-181a and tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) was verified. Following the establishment of IDD mouse models, disc height index (DHI) and the change of DHI (%DHI) were measured. The functional role of miR-181a in IDD was determined using ectopic expression and depletion and reporter assay experiments. Expression of miR-181a, TRAIL, extracellular signal-regulated kinase (ERK) pathway-related genes and inflammatory factors was evaluated. Also, the expression of collagen I and collagen II was observed. miR-181a directly targeted TRAIL. IDD mice exhibited significant degeneration of the intervertebral disc. miR-181a was downregulated while TRAIL was upregulated in mice with IDD. miR-181a upregulation and the ERK pathway inhibition could reduce expression of TRAIL, ERK pathway-related genes, inflammatory factors, and collagen I, but promote collagen II expression. Our results reveal that upregulation of miR-181a protects against inflammatory response by inactivating the ERK pathway via suppression of TRAIL in IDD mice. These results point to miR-181a as a potential therapeutic target for the clinical management of IDD.

Effect of Different Glucose Concentrations on Small RNA Levels and Adherence of Streptococcus mutans

Streptococcus mutans (S. mutans) adheres to the tooth surface, metabolizes carbohydrates, and produces acid products, leading to enamel demineralization-the onset of dental caries. Rapid acidification by S. mutans has been observed in the presence of glucose. However, little is known about the role of small RNAs (sRNAs) in S. mutans in the presence of glucose and their relationship to tooth adherence. The objective of this study was to evaluate the role of sRNAs in S. mutans (18-50 nucleotides) regarding adherence capacity under 1% and 5% glucose concentrations. The pH drop and adherence capacity in the 1% glucose condition were similar to these parameters under conditions of 5% sucrose that were published in our previous study. A total of 2149 candidate sRNA with at least 100 average reads in the 5% and 1% glucose libraries were obtained. Between the two libraries, 581 sRNAs were differentially expressed and 43 sRNAs were verified. However, the expression levels of the predicted target genes gtfC and spaP were similar between the 1% and 5% glucose conditions. The bioinformatic analysis suggested that differentially expressed sRNAs may be involved in several pathways. These findings indicate that sRNAs were induced under these glucose concentrations and a series of sRNAs were specifically induced, respectively. sRNAs that are induced under glucose stress may be involved in regulating adherence of S. mutans.

Hyperglycemia inhibition of endothelial miR-140-3p mediates angiogenic dysfunction in diabetes mellitus

OBJECTIVE

MicroRNAs (miRNAs) have emerged as promising regulators of diabetes mellitus (DM)-induced angiogenic dysfunction in endothelial cells (ECs), but information vis-à-vis the functional roles of distinct miRNAs remain surprisingly scarce. The current study was designed to elucidate the expression and function of miR-140-3p in diabetic ECs.

METHODS

miR-140-3p expression was evaluated in DM mouse model and in human ECs using RT-qPCR, Northern blot and RNA fluorescent in situ hybridization. Effects of miR-140-3p manipulation on ECs function were evaluated using cell proliferation, migration and in vitro tube formation assay. Regulation of FOXK2 transcription by miR-140-3p was determined by luciferase reporter assay and site-directed mutagenesis.

RESULTS

miR-140-3p expression was significantly down-regulated in high glucose-challenged ECs. Under normal conditions, miR-140-3p knockdown impaired endothelial proliferation and migration, and endothelial tube formation. Mechanistically, miR-140-3p exhibited its proangiogenic effects through directly inhibiting the expression of the forkhead transcription factor FOXK2. From a therapeutic standpoint, shRNA-mediated stable inhibition of FOXK2 effectively corrected miR-140-3p deficiency-induced impairment of ECs proliferation and in vitro angiogenesis.

CONCLUSION

Endothelial miR-140-3p positive regulates ECs function by directly targeting FOXK2 signaling. Deregulation of miR-140-3p/FOXK2 cascade by hyperglycemia thus serves as an important contributor to angiogenic dysfunction in DM.

microRNAs in chronic kidney disease

Chronic kidney disease (CKD) results in high morbidity and mortality worldwide causing a huge socioeconomic burden. MicroRNA (miRNA) exert critical regulatory functions by targeting downstream genes and have been associated with many pathophysiologic processes including CKD. In fact, many studies have shown that the expression of various miRNAs was significantly changed in CKD. Current investigations have focused on revealing the relationship between miRNAs and CKD states including diabetic nephropathy, lupus nephritis, focal segmental glomerulosclerosis and IgA nephropathy. In this review, we summarize the latest advances elucidating miRNA involvement in the progression of CKD and demonstrate that miRNAs have the potential to be effective biomarkers and therapeutic targets for subsequent treatment.

Early growth response protein-1 upregulates long noncoding RNA Arid2-IR to promote extracellular matrix production in diabetic kidney disease

Diabetic kidney disease (DKD) has surpassed chronic glomerulonephritis as the leading cause of end-stage renal disease. Previously, we showed that early growth response protein-1 (Egr1) plays a key role in DKD by enhancing mesangial cell proliferation and extracellular matrix (ECM) production. The long noncoding RNA (lncRNA) AT-rich interactive domain 2-IR (Arid2-IR) has been identified as a mothers against decapentaplegic homolog 3 (Smad3)-associated lncRNA in unilateral ureteral obstructive kidney disease. However, the effect of Egr1 on Arid2-IR in the development of DKD is still unknown. In this study, we found that Arid2-IR was increased in mice with high-fat diet and streptozotocin-induced type 2 diabetes and in mouse mesangial cells cultured with high glucose to mimic diabetes. Knockdown of Arid2-IR in mouse mesangial cells reduced the high expression levels of collagen-α₁(I) (Col1a1) and α-smooth muscle actin (α-SMA) induced by high glucose. Furthermore, Arid2-IR expression changed the increased expression of Col1a1 and α-SMA caused by overexpression of Egr1. Overall, these data suggest that increased Arid2-IR likely contributes to ECM production in DKD and that Egr1 promotes ECM production in DKD partly by upregulating Arid2-IR. Thus, Arid2-IR may be a new target in the treatment of DKD.

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.

Analysis of Transcription Factor-Related Regulatory Networks Based on Bioinformatics Analysis and Validation in Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) accounts for a significant proportion of liver cancer, which has become the second most common cause of cancer-related mortality worldwide. To investigate the potential mechanisms of invasion and progression of HCC, bioinformatics analysis and validation by qRT-PCR were performed. We found 237 differentially expressed genes (DEGs) including EGR1, FOS, and FOSB, which were three cancer-related transcription factors. Subsequently, we constructed TF-gene network and miRNA-TF-mRNA network based on data obtained from mRNA and miRNA expression profiles for analysis of HCC. We found that 42 key genes from the TF-gene network including EGR1, FOS, and FOSB were most enriched in the p53 signaling pathway. The qRT-PCR data confirmed that mRNA levels of EGR1, FOS, and FOSB all were decreased in HCC tissues. In addition, we confirmed that the mRNA levels of CCNB1, CCNB2, and CHEK1, three key markers of the p53 signaling pathway, were all increased in HCC tissues by bioinformatics analysis and qRT-PCR validation. Therefore, we speculated that miR-181a-5p, which was upregulated in HCC tissues, could regulate FOS and EGR1 to promote the invasion and progression of HCC by p53 signaling pathway. Overall, the study provides support for the possible mechanisms of progression in HCC.

Identification of candidate microRNA biomarkers in diabetic nephropathy: a meta-analysis of profiling studies

AIMS

The aim was to perform a meta-analysis on the miRNA expression profiling studies in diabetic nephropathy (DN) to identify candidate diagnostic biomarkers.

METHODS

A comprehensive literature search was done in several databases and 53 DN miRNA expression studies were selected. To identify significant DN-miR meta-signatures, two meta-analysis methods were employed: vote-counting strategy and the robust rank aggregation method. The targets of DN-miRs were obtained and a gene set enrichment analysis was carried out to identify the pathways most strongly affected by dysregulation of these miRNAs.

RESULTS

We identified a significant miRNA meta-signature common to both meta-analysis approaches of three up-regulated (miR-21-5p, miR-146a-5p, miR-10a-5p) and two down-regulated (miR-25-3p and miR-26a-5p) miRNAs. Besides that, subgroup analyses divided and compared the differentially expressed miRNAs according to species (human and animal), types of diabetes (T1DN and T2DN) and tissue types (kidney, blood and urine). Enrichment analysis confirmed that DN-miRs supportively target functionally related genes in signaling and community pathways in DN.

CONCLUSION

Five highly significant and consistently dysregulated miRNAs were identified, and future studies should focus on discovering their potential effect on DN and their clinical value as DN biomarkers and therapeutic mediators.

Bone marrow mesenchymal stem cells reduce ureteral stricture formation in a rat model via the paracrine effect of extracellular vesicles

With no effective therapy to prevent or treat ureteral stricture (US), a multifactorial fibrotic disease after iatrogenic injury of the ureter, the need for new therapies is urgent. Mesenchymal stem cells (MSCs) have been widely studied for treating tissue defects and excessive fibrosis, and recent studies established that one of the main therapeutic vectors of MSCs is comprised in their secretome and represented by extracellular vesicles (EVs). Thus, we have determined to explore the specific role of MSCs‐derived EVs (MSC‐EVs) treatment in a pre‐clinical model of US. The results firstly showed that either a bolus dose of MSCs or a bolus dose of MSC‐EVs (administration via renal‐arterial) significantly ameliorated ureteral fibrosis and recuperated ureter morphological development in a US rat model. We confirmed our observations through MSCs or MSC‐EVs treatment alleviated hydronephrosis, less renal dysfunction and blunted transforming growth factor‐β1 induced fibration. Due to MSC‐EVs are the equivalent dose of MSCs, and similar curative effects of transplantation of MSCs and MSC‐EVs were observed, we speculated the curative effect of MSCs in treating US might on account of the release of EVs through paracrine mechanisms. Our study demonstrated an innovative strategy to counteract ureteral stricture formation in a rat model of US.

High glucose up-regulates microRNA-34a-5p to aggravate fibrosis by targeting SIRT1 in HK-2 cells

Tubulointerstitial fibrosis (TIF) is crucial in the development of renal fibrosis in diabetic nephropathy(DN). Previous data shows that SIRT1 plays an important role on fibrosis, but the effect on TIF in DN and underlying mechanisms remains uncertain. In this study, we evaluated the vital role of SIRT1 and identified SIRT1 as a downstream target gene of microRNA-34a-5p (miR-34a-5p) in TIF of DN. The result revealed that expression of miR-34a-5p, fibronectin(FN),collagen type I (COL1) and transforming growth factor β1 (TGF-β1) were up-regulated accompanied by the corresponding down-regulation of SIRT1 in renal tissues of high fat diet and streptozotocin(HFD/STZ)induced diabetic mice with DN, and that the SIRT1 mRNA level was negatively correlated with miR-34a-5p expression in high glucose stimulated human proximal tubule cell line(HK-2) cells. We then demonstrated that overexpression of SIRT1 reduced, whereas small interfering RNA targeting SIRT1 enhanced the expressions of TGF-β1 and fibrosis-related genes including FN and COL1 in HK-2 cells. Furthermore, we identified that miR-34a-5p directly suppressed SIRT1 to increase the profibrogenic effects of TGFβ1 through targeting the 3'untranslated region of SIRT1. The functional correlation of miR-34a-5p induced SIRT1 decrease was supported by overexpression and inhibition of miR-34a-5p in HK-2 cells. All the results reveal that SIRT1 which is vital in the evolution of renal TIF in DN can be directly suppressed by miR-34a-5p, and suggest that miR-34a-5p is a new target for DN treatment.

Early Growth Response 1 (Egr1) Is a Transcriptional Activator of NOX4 in Oxidative Stress of Diabetic Kidney Disease

BACKGROUND

NADPH oxidase 4 (NOX4) plays a major role in renal oxidative stress of diabetic kidney disease (DKD). NOX4 was significantly increased in Egr1-expressing fibroblasts, but the relationship between Egr1 and NOX4 in DKD is unclear.

METHODS

For the evaluation of the potential relationship between Egr1 and NOX4, both were detected in HFD/STZ-induced mice and HK-2 cells treated with TGF-β1. Then, changes in NOX4 expression were detected in HK-2 cells and mice with overexpression and knockdown of Egr1. The direct relationship between Egr1 and NOX4 was explored via chromatin immunoprecipitation (ChIP).

RESULTS

We found increased levels of Egr1, NOX4, and α-SMA in the kidney cortices of diabetic mice and in TGF-β1-treated HK-2 cells. Overexpression or silencing of Egr1 in HK-2 cells could upregulate or downregulate NOX4 and α-SMA. ChIP assays revealed that TGF-β1 induced Egr1 to bind to the NOX4 promoter. Finally, Egr1 overexpression or knockdown in diabetic mice could upregulate or downregulate the expression of NOX4 and ROS, and α-SMA was also changed.

CONCLUSION

Our study provides strong evidence that Egr1 is a transcriptional activator of NOX4 in oxidative stress of DKD. Egr1 contributes to DKD by enhancing EMT, in part by targeting NOX4.

Down-regulation of miR-23a inhibits high glucose-induced EMT and renal fibrogenesis by up-regulation of SnoN

It has been reported that transforming growth factor-β1 (TGF-β1) signaling plays an important role in the development of diabetic nephropathy (DN). The nuclear transcription co-repressor Ski-related novel protein N (SnoN) is a critical negative regulator of TGF-β1/Smad signal pathway, involving in tubule epithelial-mesenchymal transition (EMT), extracellular matrix (ECM) accumulation, and tubulointerstitial fibrosis. In this study, we focused on miR-23a as a regulator of SnoN. Our purpose is to study the effects of miR-23a on high glucose (HG)-induced EMT process and ECM deposition in HK2 cells. We found that miR-23a was up-regulated in renal tissues of diabetic patients and HG-induced HK2 cells. Besides, the high level of miR-23a was closely associated with decreased SnoN expression. Knockdown of miR-23a increased SnoN expression and in turn suppressed HG-induced EMT and renal fibrogenesis. Introduction of miR-23a decreased SnoN expression and enhanced the profibrogenic effects of HG on HK2 cells. Next, bioinformatics analysis predicted that the SnoN was a potential target gene of miR-23a. Luciferase reporter assay demonstrated that miR-23a could directly target SnoN. We demonstrated that overexpression of SnoN was sufficient to inhibit HG-induced EMT and renal fibrogenesis in HK2 cells. Furthermore, down-regulation of SnoN partially reversed the protective effect of miR-23a knockdown on HG-induced EMT and renal fibrogenesis in HK2 cells. Collectively, miR-23a and SnoN significantly impact on the progression of HG-induced EMT and renal fibrogenesis in vitro, and they may represent novel targets for the prevention strategies of renal fibrosis in the context of DN.