Serum granulosa cell-derived TNF-α promotes inflammation and apoptosis of renal tubular cells and PCOS-related kidney injury through NF-κB signaling.

Polycystic ovary syndrome (PCOS) is a disorder with endocrinal and metabolic problems in reproductive aged women. Evidence shows that PCOS is in a high prone trend to develop kidney diseases. In this study, we investigated the mediators responsible for PCOS-related kidney injury. We found that tumor necrosis factor (TNF-α) levels were significantly increased in serum and primary cultured granulosa cells (GCs) from PCOS patients. Serum TNF-α levels were positively correlated with serum testosterone and luteinizing hormone (LH)/follicle-stimulating hormone (FSH) ratio, suggesting its positive role in the severity of PCOS. Serum TNF-α levels were also positively correlated with the levels of urinary KapU, LamU, α1-MU and ß2-MU, the markers for renal tubular cell-derived proteinuria. We established a PCOS mouse model by resection of the right kidney, followed by daily administration of dihydrotestosterone (DHT, 27.5 µg, i.p.) from D7 for 90 days. We found that TNF-α levels were significantly increased in the ovary and serum of the mice, accompanied by increased renal tubular cell apoptosis, inflammation and fibrosis in kidneys. Furthermore, the receptor of TNF-α, tumor necrosis factor receptor 1 (TNFR1), was significantly upregulated in renal tubular cells. We treated human ovarian granulosa-like tumor cells (KGN) with DHT (1 µg/ml) in vitro, the conditioned medium derived from the granulosa cell culture greatly accelerated apoptotic injury in human proximal tubular epithelial cells (HKC-8), which was blocked after knockdown of TNF-α in KGN cells. Furthermore, knockdown of TNFR1 in renal tubular epithelial cells greatly ameliorated cell injury induced by granulosa cell-derived conditioned medium. These results suggest that serum TNF-α plays a key role in mediating inflammation and apoptosis in renal tubular cells associated with PCOS-related kidney injury.

Critical roles of SMYD2 lysine methyltransferase in mediating renal fibroblast activation and kidney fibrosis.

SET and MYND domain protein 2 (SMYD2) is a lysine methyltransferase that mediates histone H3 lysine 36 trimethylation (H3K36me3) and acts as a regulator of tumorgenesis and cystic growth. However, its role in renal fibrosis remains unknown. In this study, we found that SMYD2 was highly expressed in the murine kidney of renal fibrosis induced by unilateral ureteral obstruction, and primarily located in interstitial fibroblasts and renal tubular epithelial cells. Pharmacological inhibition of SMYD2 with AZ505, a highly selective inhibitor of SMYD2, protected against renal fibrosis and inhibited activation/proliferation of renal interstitial fibroblasts and conversion of epithelial cells to a profibrotic phenotype in this model. In cultured renal interstitial fibroblasts, treatment with AZ505 or silencing of SMYD2 by specific siRNA also inhibited serum- or TGF-ß1-induced activation and proliferation of renal interstitial fibroblasts. Mechanistic studies showed that SMYD2 inhibition reduced phosphorylation of several profibrotic signaling molecules, including Smad3, extracellular signal-regulated kinase 1/2, AKT, signal transducer and activator of transcription-3 and nuclear factor-κB in both injured kidney and cultured renal fibroblasts. AZ505 was also effective in suppressing renal expression of Snail and Twist, two transcriptional factors that mediate renal partial epithelial-mesenchymal transition and fibrosis. Conversely, AZ505 treatment prevented downregulation of Smad7, a renoprotective factor in vivo and in vitro. These results indicate that SMYD2 plays a critical role in mediating conversion of epithelial cells to a profibrotic phenotype, renal fibroblast activation and renal fibrogenesis, and suggest that SMYD2 may be a potential target for the treatment of chronic fibrosis in kidney disease.

Blocking the histone lysine 79 methyltransferase DOT1L alleviates renal fibrosis through inhibition of renal fibroblast activation and epithelial-mesenchymal transition.

Disruptor of telomeric silencing-1 like (DOT1L) protein specifically catalyzes the methylation of histone H3 on Lys79 (H3K79) and is implicated in tumors. But its role in tissue fibrosis remains unclear. Here we demonstrated that injury to the kidney increased DOT1L expression and H3K79 dimethylation in renal tubular epithelial cells and myofibroblasts in a murine model of unilateral ureteral obstruction. Administration of EPZ5676, a highly selective inhibitor of DOT1L, attenuated renal fibrosis. Treatment with EPZ5676 or DOT1L small interfering RNA also inhibited TGF-ß1 and serum-induced activation of renal interstitial fibroblasts and epithelial-mesenchymal transition (EMT) in vitro. Moreover, blocking DOT1L abrogated injury-induced epithelial G2/M arrest; reduced expression of Snail, Twist, and Notch1; and inactivated several profibrotic signaling molecules in the injured kidney, including Smad3, epidermal growth factor receptor, platelet-derived growth factor receptor, signal transducer and activator of transcription 3, protein kinase B, and NF-κB. Conversely, DOT1L inhibition increased expression of phosphatase and tensin homolog, a protein associated with dephosphorylation of tyrosine kinase receptors, and prevented decline in levels of Klotho and Smad7, 2 renoprotective factors. Thus, our data indicate that targeting DOT1L attenuates renal fibrosis through inhibition of renal fibroblasts and EMT by suppressing activation of multiple profibrotic signaling pathways while retaining expression of renoprotective factors.-Liu, L., Zou, J., Guan, Y., Zhang, Y., Zhang, W., Zhou, X., Xiong, C., Tolbert, E., Zhao, T. C., Bayliss, G., Zhuang, S. Blocking the histone lysine 79 methyltransferase DOT1L alleviates renal fibrosis through inhibition of renal fibroblast activation and epithelial-mesenchymal transition.

Selective inhibition of class IIa histone deacetylases alleviates renal fibrosis.

In this study, we examined the effect of MC1568, a selective class IIa histone deacetylase (HDAC) inhibitor, on the development and progression of renal fibrosis in a murine model of renal fibrosis induced by unilateral ureteral obstruction (UUO). All 4 class IIa HDAC isoforms, in particular HDAC4, were up-regulated in renal epithelial cells of the injured kidney. Administration of MC1568 immediately after UUO injury reduced expression of α-smooth muscle actin (α-SMA), fibronectin, and collagen 1. MC1568 treatment or small interfering RNA-mediated silencing of HDAC4 also suppressed expression of those proteins in cultured renal epithelial cells. Mechanistically, MC1568 abrogated UUO-induced phosphorylation of Smad3, NF-κB, and up-regulation of integrin ɑVß6 in the kidney and inhibited TGF-ß1-induced responses in cultured renal epithelial cells. MC1568 also increased renal expression of klotho, bone morphogenetic protein 7, and Smad7. Moreover, delayed administration of MC1568 at 3 d after ureteral obstruction reversed the expression of α-SMA, fibronectin, and collagen 1 and increased expression of matrix metalloproteinase (MMP)-2 and -9. Collectively, these results suggest that selectively targeting class IIa HDAC isoforms (in particular HDAC4) may inhibit development and progression of renal fibrosis by suppressing activation and expression of multiple profibrotic molecules and increasing expression of antifibrotic proteins and MMPs.-Xiong, C., Guan, Y., Zhou, X., Liu, L., Zhuang, M. A., Zhang, W., Zhang, Y., Masucci, M. V., Bayliss, G., Zhao, T. C., Zhuang, S. Selective inhibition of class IIa histone deacetylases alleviates renal fibrosis.

Potential urine biomarkers for the diagnosis of prediabetes and early diabetic nephropathy based on ISN CKHDP program.

BACKGROUND: Diabetic nephropathy (DN) is a major complication of diabetes mellitus (DM), and the most frequent cause of end-stage renal disease (ESRD) in many countries. Urinary extracellular vesicles (UEVs) are considered a rich non-invasive source of markers for renal diseases. In this study, UEV enrichment and analysis in diabetic nephropathy (DN) was performed in a community epidemiological survey supported through the ISN CKHDP program. MATERIALS AND METHODS: Patients were divided into five groups according to severity of kidney damage. A hydrostatic dialysis method was used for UEV enrichment followed by quantitation using Coomassie protein assays and subsequent adjustment using urinary creatinine levels. UEVs were then characterized by transmission electron microscopy (TEM), nanoparticle tracking analysis (NTA), and Western blotting of tumor susceptibility gene product TSG101. Two-dimensional DIGE (2D-DIGE) was used to analyze differential protein expression in the UEVs. Mass spectrometry (MS) was conducted and MASCOT search engine was used to identify potential biomarkers. RESULTS: Bradford protein assay showed that protein concentration of UEVs in diabetics with kidney injury increased significantly as compared to normal controls. UEVs present a round, cup-shaped, membrane-encapsulated structure under TEM, and the main peak of UEVs show 55 - 110 nm nanoparticles with NTA. MS and MASCOT identified 22 differential proteins, and MASP2, CALB1, S100A8, and S100A9 were selected as potential biomarkers of early DN based on bioinformatic analysis. DISCUSSION: Our results show UEV proteome changes in different stages of DN. The results of this study show four unique proteins that undergo changes in early DN. These promising discoveries may prompt a new field of research focused on improving the diagnosis of DN.

Targeting histone methyltransferase enhancer of zeste homolog-2 inhibits renal epithelial-mesenchymal transition and attenuates renal fibrosis.

Enhancer of zeste homolog-2 (EZH2) is a methyltransferase that induces histone H3 lysine 27 trimethylation (H3K27me3) and functions as an oncogenic factor in many cancer types. Its role in renal epithelial-mesenchymal transition (EMT) remains unknown. In this study, we found that EZH2 and H3K27me3 were highly expressed in mouse kidney with unilateral ureteral obstruction and cultured mouse kidney proximal tubular (TKPT) cells undergoing EMT. Inhibition of EZH2 with 3-deazaneplanocin A (3-DZNeP) attenuated renal fibrosis, which was associated with preserving E-cadherin expression and inhibiting Vimentin up-regulation in the obstructed kidney. Treatment with 3-DZNeP or transfection of EZH2 siRNA also inhibited TGF-ß1-induced EMT of TKPT cells. Injury to the kidney or cultured TKPT cells resulted in up-regulation of Snail-l family transcriptional repressor (Snail)-1 and Twist family basic helix-loop-helix (BHLH) transcription factor (Twist)-1, which are 2 transcription factors, and down-regulation of phosphatase and tensin homolog, a protein tyrosine phosphatase associated with inhibition of PI3K-protein kinase B (AKT) signaling; EZH2 inhibition or silencing reversed all those responses. 3-DZNeP was also effective in suppressing epithelial arrest at the G2/M phase and dephosphorylating AKT and ß-catenin in vivo and in vitro. These data indicate that EZH2 activation contributes to renal EMT and fibrosis through activation of multiple signaling pathways and suggest that EZH2 has potential as a therapeutic target for treatment of renal fibrosis.-Zhou, X., Xiong, C., Tolbert, E., Zhao, T. C., Bayliss, G., Zhuang, S. Targeting histone methyltransferase enhancer of zeste homolog-2 inhibits renal epithelial-mesenchymal transition and attenuates renal fibrosis.

Comparison of Hydrostatic Filtration Dialysis with Ultracentrifugation Methods for the Identification and Proteomic Profiling of Urinary Extracellular Vesicles.

BACKGROUND: Urinary extracellular vesicles (UEVs) carry rich markers of their parent cells, so they can serve as possible biomarkers of kidney diseases. METHODS: In this study, we isolated urinary extracellular vesicles from five individuals using a simple, clinically applicable method called hydrostatic filtration dialysis (HFD) and compared it to the gold-standard ultracentrifuga-tion (UC) with transmission electron microscopy (TEM). We also employed a proteomic approach using pooled human urine samples from the same five individuals to profile the protein composition of UEVs to evaluate the effectiveness of these two methods. RESULTS: Notably, using TEM, we found that all isolations contained 0 - 400 nm vesicles with the traditionally reported morphology, although the TEM results showed that the UEVs isolated from HFD compared to those from UC are larger and more extensive. We obtained a total of 2,564 UEV proteins in the two methods. We showed a large overlap (2,185 > 85%) between the proteins identified by both isolation methods. The result also showed that the obtained proteins in extracellular vesicles, which are isolated with these methods, are consistent with the results in currently available databases. However, in the associated gene ontologies, the enriched proteins found by the two methods showed some differences. CONCLUSIONS: The HFD method is clinically feasible and allows large-scale protein profiling of UEV biomarkers. The results of this study also provide valuable UEV protein data from the methodological comparison, which might be valuable to other researchers.

Delayed administration of suramin attenuates peritoneal fibrosis in rats.

BACKGROUND: Peritoneal fibrosis is the most common complication of peritoneal dialysis, but there is currently no effective treatment. We previously reported that suramin pretreatment prevents the development of peritoneal fibrosis in a rat model of peritoneal fibrosis induced by chlorhexidine gluconate (CG). Here, we further examined the effectiveness of delayed administration of suramin on peritoneal fibrosis and the mechanism (s) involved in this process. METHODS: In the rat model of peritoneal fibrosis induced by CG, suramin or saline was administered at day 21 and 28. All rats were then sacrificed to collect peritoneal tissues for Western blot analysis and histological staining at day 35. RESULTS: Our results demonstrated that delayed administration of suramin starting at 21 days following CG injection can ameliorate peritoneal damage, with greater efficacy after two injections. Suramin also reduced the expression of α-smooth muscle actin, Collagen 1, and Fibronectin and suppressed phosphorylation of Smad-3, epidermal growth factor receptor (EGFR), signal transducers, activator of transcription 3 (STAT3) as well as extracellular signal-regulated kinases 1/2 (ERK 1/2) in the peritoneum injured with CG. Moreover, delayed administration of suramin inhibited overproduction of transforming growth factor-ß1(TGF-ß1) and expression of several pro-inflammatory cytokines, including monocyte chemoattractant protein-1, tumor necrosis factor-α, interleukin-1, and interleukin-6. CONCLUSIONS: Our results indicated that suramin can attenuate progression of peritoneal fibrosis by a mechanism involving inhibition of the TGF-ß1/Smad3 and EGFR signaling pathways as well as suppression of multiple proinflammatory cytokines. Thus, suramin may have the potential to offer an effective treatment for peritoneal fibrosis.

WITHDRAWN: Salvianolate attenuates renal fibrosis in rat models of diabetic nephropathy by inhibiting inflammation and oxidative stress mechanisms.

This article has been withdrawn at the request of the author(s) and/or editor. The Publisher apologizes for any inconvenience this may cause. The full Elsevier Policy on Article Withdrawal can be found at https://www.elsevier.com/about/our-business/policies/article-withdrawal.

Inhibition of EGF Receptor Blocks the Development and Progression of Peritoneal Fibrosis.

Inhibitors of EGF receptor (EGFR) have antifibrotic effects in several organs, but the effect of these inhibitors on the development of peritoneal fibrosis is unknown. Here, we explored the therapeutic effect of gefitinib, a specific inhibitor of EGFR, on the development and progression of peritoneal fibrosis in a rat model. Daily intraperitoneal injections of chlorhexidine gluconate induced peritoneal fibrosis, indicated by thickening of the submesothelial area with an accumulation of collagen fibrils and activation of myofibroblasts, accompanied by time-dependent phosphorylation of EGFR. Administration of gefitinib immediately after injury prevented the onset of peritoneal fibrosis and delayed administration after the onset of peritoneal fibrosis halted fibrosis progression. Gefitinib treatment abrogated the increased phosphorylation of EGFR, Smad3, signal transducer and activator of transcription 3, and NF-κB during peritoneal fibrosis; it also inhibited the accompanying overproduction of TGF-ß1 and proinflammatory cytokines and the infiltration of macrophages to the injured peritoneum. Moreover, gefitinib significantly reduced the peritoneal increase of CD31-positive blood vessels and vascular EGF-positive cells after injury. Finally, gefitinib also attenuated high glucose-induced peritoneal fibrosis in rats and abrogated TGF-ß1-induced phosphorylation of Smad3 and the epithelial-to-mesenchymal transition of cultured human peritoneal mesothelial cells. These results demonstrate that EGFR contributes to peritoneal fibrosis, inflammation, and angiogenesis, suggesting that EGFR inhibitors may have therapeutic potential in attenuating peritoneal fibrosis.

EGF Receptor Inhibition Alleviates Hyperuricemic Nephropathy.

Hyperuricemia is an independent risk factor for CKD and contributes to kidney fibrosis. In this study, we investigated the effect of EGF receptor (EGFR) inhibition on the development of hyperuricemic nephropathy (HN) and the mechanisms involved. In a rat model of HN induced by feeding a mixture of adenine and potassium oxonate, increased EGFR phosphorylation and severe glomerular sclerosis and renal interstitial fibrosis were evident, accompanied by renal dysfunction and increased urine microalbumin excretion. Administration of gefitinib, a highly selective EGFR inhibitor, prevented renal dysfunction, reduced urine microalbumin, and inhibited activation of renal interstitial fibroblasts and expression of extracellular proteins. Gefitinib treatment also inhibited hyperuricemia-induced activation of the TGF-ß1 and NF-κB signaling pathways and expression of multiple profibrogenic cytokines/chemokines in the kidney. Furthermore, gefitinib treatment suppressed xanthine oxidase activity, which mediates uric acid production, and preserved expression of organic anion transporters 1 and 3, which promotes uric acid excretion in the kidney of hyperuricemic rats. Thus, blocking EGFR can attenuate development of HN via suppression of TGF-ß1 signaling and inflammation and promotion of the molecular processes that reduce uric acid accumulation in the body.

Suramin inhibits the development and progression of peritoneal fibrosis.

Peritoneal fibrosis is one of the most serious complications in patients with peritoneal dialysis (PD) and is associated with the loss of peritoneal membrane ultrafiltration function. In this study, we investigated whether suramin, an inhibitor that blocks multiple growth factors by binding to their receptors, would prevent development of peritoneal fibrosis in a rat model. Rats were given a daily intraperitoneal injection of chlorhexidine gluconate (CG) for 3 weeks to induce peritoneal fibrosis. Administration of suramin at 5, 10, and 20 mg/kg dose-dependently attenuated peritoneal membrane thickening and expression of collagen I, fibronectin, and α-smooth muscle actin. Increased expression of transforming growth factor-ß1 (TGF-ß1) and phosphorylation of Smad3 was detected in fibrotic peritoneum and inhibited by suramin treatment. Suramin was also effective in blocking CG-induced phosphorylation of inhibitor of κB (IκB) and nuclear factor (NF)-κBp65, expression of several inflammatory cytokines, and infiltration of macrophages in the peritoneum. Moreover, suramin suppressed angiogenesis and expression of vascular endothelial growth factor, a molecule associated with angiogenesis in the injured peritoneum. Therefore, our results indicate that suramin treatment can effectively alleviate the development of peritoneal fibrosis by suppression of TGF-ß1 signaling, inflammation, and angiogenesis, and suggest that suramin may have therapeutic potential for prevention of peritoneal fibrosis in PD patients.

Prevalence and determinants of parathyroid dysfunction in elderly patients on hemodialysis.

BACKGROUND: The goal of this study was to investigate underlying factors of parathyroid dysfunction in elderly patients undergoing maintenance hemodialysis. METHODS: A total of 286 patients on maintenance hemodialysis were included. Hemoglobin, serum creatinine (Scr), blood urea nitrogen (BUN), serum calcium, serum phosphorus (P), intact parathyroid hormone (iPTH), and serum albumin (Alb) were measured and analyzed both before and after dialysis. RESULTS: A higher incidence of low iPTH level (<150 pg/l) was observed in the elderly group than that in the non-elderly group (55.8 vs. 36.7%, p < 0.05). Elderly patients had a shorter dialysis duration, lighter dry weight, lower concentrations of BUN, Scr, P, iPTH, Alb and standard protein nitrogen present rate (nPNA) compared to that of non-elderly group patients (p < 0.05). CONCLUSIONS: Low iPTH level occurs more frequently in elderly hemodialysis patients. Furthermore, age, serum P, serum Alb and nPNA were independently associated with a low iPTH level.

Pharmacological inhibition of Src family kinases attenuates hyperuricemic nephropathy.

Hyperuricemia is an independent risk factor for chronic kidney disease and contributes to renal fibrosis. This study aims to investigate the effect of Src family kinase (SFK) inhibition on the development of hyperuricemic nephropathy (HN) and the mechanisms involved. In a rat model of HN, feeding rats a mixture of adenine and potassium oxonate increased Src phosphorylation, severe glomerular sclerosis, and renal interstitial fibrosis, accompanied by renal dysfunction and increased urine microalbumin excretion. Administration of PP1, a highly selective SFK inhibitor, prevented renal dysfunction, reduced urine microalbumin, and inhibited activation of renal interstitial fibroblasts and expression of extracellular proteins. PP1 treatment also inhibited hyperuricemia-induced activation of the TGF-ß1/Smad3, STAT3, ERK1/2, and NF-κB signaling pathways and expression of multiple profibrogenic cytokines/chemokines in the kidney. Furthermore, PP1 treatment significantly reduced serum uric acid levels and xanthine oxidase activity. Thus, blocking Src can attenuate development of HN via a mechanism associated with the suppression of TGF-ß1 signaling, inflammation, and uric acid production. The results suggest that Src inhibition might be a promising therapeutic strategy for HN.

Metabolism Score for Visceral Fat (METS-VF): A New Predictive Surrogate for CKD Risk.

Purpose: Metabolic disorders are closely related to the occurrence and development of chronic kidney disease (CKD). We explored the prospective association between the Metabolic Score for Visceral Fat (METS-VF) and CKD in a 5-year follow-up study. Patients and Methods: In this cohort study, 631 adults not suffering from CKD from Wanzhai Town, in China in 2012 were included at baseline and followed up in 2017 and 2018. Multivariable logistic regression was used to calculate odds ratios (ORs) and 95% confidence intervals (CIs) for the association between METS-VF and CKD risk. Area under the receiver operating characteristic curve (AUC) analyses were used to evaluate the ability of METS-VF, waist-to-height ratio (WhtR), visceral adiposity index (VAI), homeostatic model assessment of insulin resistance (HOMA-IR), body mass index (BMI) to predict CKD risk. Results: We identified 103 CKD cases during follow-up. After adjustment for confounding factors, comparing the lowest quartile of METS-VF, the OR (95% CI) of CKD risk in the highest quartile was 3.04 (1.39-6.64). The per Standard deviation (SD) increase in METS-VF was positively correlated with CKD risk. The AUC of METS-VF for predicting CKD risk was, in general, higher than that for WhtR, VAI, HOMA-IR, and BMI. Conclusion: METS-VF may be an indicator for predicting CKD risk.

Associaton of Retinol Binding Protein 4 (RBP4) Levels With Hyperuricemia: A Cross-Sectional Study in a Chinese Population.

Background: There are few studies on predictive biomarkers for hyperuricemia, and the predictive value of these biomarkers tends to be poor. Additionally, no reports have described the predictive value of retinol binding protein 4 (RBP4) for hyperuricemia. Purpose: This study was performed to evaluate the value of RBP4 for predicting the risk of hyperuricemia in a general population, determine whether RBP4 could be used alone or in combination with other factors to predict the risk of hyperuricemia in the general population, and establish an optimum predictive model. Methods: We conducted a population-based cross-sectional survey in 2018, involving a questionnaire, physical examination, and laboratory testing. We enrolled 2303 individuals by stratified random sampling, and 2075 were included in the data analysis after applying the eligibility criteria. Results: Serum RBP4 level had a highly significant association with hyperuricemia (P<0.001). After adjusting for potential confounders, logistic regression indicated that the risk of hyperuricemia was highest in the highest RBP4 quartile (odds ratio: 7.9, 95% confidence interval [CI]: 4.18-14.84, compared to the lowest quartile). The area under the receiver operating characteristic (ROC) curve (AUC) for RBP4 was 0.749 (95% CI: 0.725-0.774, P<0.001), which was higher than that for all the other predictors assessed. The optimum model for predicting hyperuricemia in the general population consisted of RBP4, sex (male), body mass index, serum creatinine, high-sensitivity C-reactive protein, fasting blood glucose, insulin, and alcohol consumption. The AUC was 0.804 (95% CI: 0.782-0.826, P<0.001). Conclusions: RBP4 is strongly associated with hyperuricemia, and its predictive value was higher than that of traditional predictors.

Histone demethylase JMJD3 protects against renal fibrosis by suppressing TGFß and Notch signaling and preserving PTEN expression.

Rationale: The Jumonji domain containing-3 (JMJD3), a specific histone demethylase for trimethylation on histone H3 lysine 27 (H3K27me3), is associated with the pathogenesis of many diseases, but its role in renal fibrosis remains unexplored. Here we examined the role of JMJD3 and mechanisms involved in the activation of renal fibroblasts and development of renal fibrosis. Methods: Murine models of 5/6 surgical nephrectomy (SNx) and ureteral unilateral obstruction (UUO) were used to assess the effect of a specific JMJD3 inhibitor, GSKJ4, and genetic deletion of JMJD3 from FOXD1 stroma-derived renal interstitial cells on the development of renal fibrosis and activation of renal interstitial fibroblasts. Cultured rat renal interstitial fibroblasts (NRK-49F) and mouse renal tubular epithelial cells (mTECs) were also used to examine JMJD3-mediated activation of profibrotic signaling. Results: JMJD3 and H3K27me3 expression levels were upregulated in the kidney of mice subjected to SNx 5/6 and UUO. Pharmacological inhibition of JMJD3 with GSKJ4 or genetic deletion of JMJD3 led to worsening of renal dysfunction as well as increased deposition of extracellular matrix proteins and activation of renal interstitial fibroblasts in the injured kidney. This was coincident with decreased expression of Smad7 and enhanced expression of H3K27me3, transforming growth factor ß1 (TGFß1), Smad3, Notch1, Notch3 and Jagged1. Inhibition of JMJD3 by GSK J4 or its specific siRNA also resulted in the similar responses in cultured NRK-49F and mTECs exposed to serum or TGFß1. Moreover, JMJD3 inhibition augmented phosphorylation of AKT and ERK1/2 in vivo and in vitro. Conclusion: These results indicate that JMJD3 confers anti-fibrotic effects by limiting activation of multiple profibrotic signaling pathways and suggest that JMJD3 modulation may have therapeutic effects for chronic kidney disease.

Inhibition of Glycogen Synthase Kinase 3ß Alleviates Chronic Renal Allograft Dysfunction in Rats.

BACKGROUND: Chronic renal allograft dysfunction (CRAD) is a major condition that impedes the long-term survival of renal allografts. However, the mechanism of CRAD is obscure, and the effective strategies for controlling the progression of CRAD are lacking. The present study used a CRAD rat model to assess the effect of glycogen synthase kinase 3ß (GSK-3ß) inhibition on the development of CRAD. METHODS: A classical F334-to-LEW orthotopic renal transplantation was performed on the CRAD group. The treatment group was treated with the GSK-3ß inhibitor 4-benzyl-2-methyl-1,2,4-thiadiazolidine-3,5-dione for 12 consecutive weeks following renal transplantation. The study included uninephrectomized F344 and Lewis rats as control subjects. Twelve weeks post surgery, the rats were retrieved for analysis of renal function, urine protein levels, histological, immunohistochemical, and molecular biological parameters. RESULTS: Administration of 4-benzyl-2-methyl-1,2,4-thiadiazolidine-3,5-dione inactivated GSK-3ß and thereby improved renal function, attenuated proteinuria, and reduced renal tissue damage in CRAD rats. Besides, inactivation of GSK-3ß inhibited nuclear factor-κB activation, macrophage infiltration, and expression of multiple proinflammatory cytokines/chemokines. Inhibition of GSK-3ß also decreased the levels of malondialdehyde, increased superoxide dismutase levels, upregulated the expression of heme oxygenase-1 and NAD(P)H quinone oxidoreductase-1, and enhanced nuclear translocation of nuclear factor erythroid 2-related factor 2 in the kidneys of CRAD rats. CONCLUSIONS: Inhibition of GSK-3ß attenuates the development of CRAD by inhibiting inflammation and oxidant stress. Thus, GSK-3ß inhibition may represent a potential therapeutic strategy for the prevention and treatment of CRAD.

Pharmacologic Targeting of BET Proteins Attenuates Hyperuricemic Nephropathy in Rats.

Hyperuricemia is an independent risk factor for renal damage and promotes the progression of chronic kidney disease. In this study, we investigated the effect of I-BET151, a small-molecule inhibitor targeting the bromodomain and extraterminal (BET) proteins, on the development of hyperuricemic nephropathy (HN), and the mechanisms involved. Expression levels of bromodomain-containing protein 2 and 4, but not 3 were increased in the kidney of rats with HN; administration of I-BET151 effectively prevented renal dysfunction, decreased urine microalbumin, and attenuated renal fibrosis as indicated by reduced activation of renal interstitial fibroblasts and expression of fibronectin and collagen I in HN rats. Mechanistic studies show that I-BET151 treatment inhibited transition of renal epithelial cells to a mesenchymal cell type as evidenced by preservation of E-cadherin and reduction of vimentin expression. This was coincident with reduced expression of TGF-ß1 and dephosphorylation of Smad3 and ERK1/2. I-BET151 was also effective in inhibiting phosphorylation of NF-κB, expression of multiple cytokines and chemokines, and infiltration of macrophages to the injured kidney. Although there were increased serum levels of uric acid and xanthine oxidase, an enzyme that catalyzes production of uric acid, and decreased expression of renal organic anion transporter 1 and 3 that promote urate excretion in the model of HN, and reduced expression levels of urine uric acid, I-BET151 treatment did not affect these responses. Collectively, our results indicate that I-BET151 alleviates HN by inhibiting epithelial to mesenchymal transition and inflammation in association with blockade of TGF-ß, ERK1/2 and NF-κB signaling.

Potential role of anti-inflammatory HDL subclasses in metabolic unhealth/obesity.

High-density lipoprotein (HDL) particles comprising heterogeneous subclasses of different functions exert anti-inflammatory effects by interacting with immune-response cells. However, the relationship of HDL subclasses with immune-response cells in metabolic unhealth/obesity has not been defined clearly. The purpose of this study was to delineate the relational changes of HDL subclasses with immune cells and inflammatory markers in metabolic unhealth/obesity to understand the role of anti-inflammatory HDL subclasses. A total of 316 participants were classified by metabolic health. HDL subclasses were detected by microfluidic chip electrophoresis. White blood cell (WBC) counts and lymphocytes were assessed using automatic haematology analyser. Levels of high-sensitivity C-reactive protein (hs-CRP) and interleukin 6 (IL-6) were measured. In our study, not only the distribution of HDL subclasses, but also HDL-related structural proteins changed with the deterioration of metabolic disease. Moreover, lymphocytes and inflammation factors significantly gradually increased. The level of HDL2b was negatively associated with WBC, lymphocytes and hs-CRP in multivariable linear regression analysis. In multinomial logistic regression analysis, high levels of HDL3 and low levels of HDL2b increased the probability of having an unfavourable metabolic unhealth/obesity status. We supposed that HDL2b particles may play anti-inflammation by negatively regulating lymphocytes activation. HDL2b may be a therapeutic target for future metabolic disease due to the anti-inflammatory effects.