Long noncoding RNA Glis2 regulates podocyte mitochondrial dysfunction and apoptosis in diabetic nephropathy via sponging miR-328-5p.

Podocyte apoptosis exerts a crucial role in the pathogenesis of DN. Recently, long noncoding RNAs (lncRNAs) have been gradually identified to be functional in a variety of different mechanisms associated with podocyte apoptosis. This study aimed to investigate whether lncRNA Glis2 could regulate podocyte apoptosis in DN and uncover the underlying mechanism. The apoptosis rate was detected by flow cytometry. Mitochondrial membrane potential (ΔΨM) was measured using JC-1 staining. Mitochondrial morphology was detected by MitoTracker Deep Red staining. Then, the histopathological and ultrastructure changes of renal tissues in diabetic mice were observed using periodic acid-Schiff (PAS) staining and transmission electron microscopy. We found that lncRNA Glis2 was significantly downregulated in high-glucose cultured podocytes and renal tissues of db/db mice. LncRNA Glis2 overexpression was found to alleviate podocyte mitochondrial dysfunction and apoptosis. The direct interaction between lncRNA Glis2 and miR-328-5p was confirmed by dual luciferase reporter assay. Furthermore, lncRNA Glis2 overexpression alleviated podocyte apoptosis in diabetic mice. Taken together, this study demonstrated that lncRNA Glis2, acting as a competing endogenous RNA (ceRNA) of miRNA-328-5p, regulated Sirt1-mediated mitochondrial dysfunction and podocyte apoptosis in DN.

Linc279227 contributes to mitochondrial dysfunction in high glucose-treated mouse renal tubular epithelial cells.

BACKGROUND: The aberrant expression of long noncoding RNAs (lncRNAs) has been associated with diabetic nephropathy (DN), a major complication of diabetes mellitus (DM). This study investigated the differential expression of lncRNAs in DM without renal damage and DM with renal damage, known as DN, and elucidated the functions of a pathogenic lncRNA. METHODS: High-throughput sequencing was performed on the kidneys of male db/db mice with kidney injury, db/db mice without kidney involvement and db/m control littermates. Linc279227 expression was confirmed by RT‒qPCR and fluorescence in situ hybridization. The effects of linc279227 on high glucose (HG)-treated renal tubular epithelial cells (RTECs) were evaluated by autophagy flux monitoring, Western blot determination and mitochondrial morphological detection. RESULTS: With high-throughput sequencing, we identified a 1024 nt long intergenic noncoding RNA, TCONS_00279227 (linc279227), whose expression was markedly increased in the kidneys of db/db mice with kidney injury compared to db/db mice without kidney injury and db/m control littermates. Fluorescence in situ hybridization confirmed that linc279227 was mainly located in the renal tubules of mice with DN. In vitro, linc279227 expression was found to be significantly increased in RTECs treated with high glucose (HG) for 48 h. Silencing linc279227 markedly restored the levels of autophagy-/mitophagy-associated proteins in HG-stimulated RTECs. Furthermore, silencing linc279227 reduced phosphorylated Drp1 expression and increased Mfn2 expression in RTECs exposed to HG. CONCLUSION: Our data suggest that linc279227 plays an important role in mitochondrial dysfunction in HG-treated RTECs and that silencing linc279227 rescues RTECs exposed to HG.

LncRNA MEG3 inhibits renal fibrinoid necrosis of diabetic nephropathy via the MEG3/miR-21/ORAI1 axis.

INTRODUCTION: Diabetic nephropathy (DN) is one of the most common and lethal diabetic complications worldwide and is associated with a high risk of mortality. However, the exact mechanism behind its development is unknown. The mesangial cells (MCs) and non-coding RNAs are critical for DN, but it is unknown whether a MEG3/miR-21/ORAI1 regulatory axis exists in MCs. Hence, in this study, we aimed to understand whether the MEG3/miR-21/ORAI1 regulatory axis has a role in the pathophysiology of DN. RESULTS: We demonstrated that high-glucose stimuli downregulated MEG3 and ORAI1 expression while enhancing miR-21 expression. Exogenous miR-21 mimics inhibited ORAI1 expression, which was partially salvaged or reversed by MEG3 overexpression. Furthermore, RIP assay demonstrated that the beads labeled with AGO2 antibody could enrich more miR-21 and MEG3 than those labeled with control IgG antibody; both of them formed the RNA-induced silencing complex. Further, the biochemical indicators of db/db mice significantly improved, and renal fibrinoid necrosis was ameliorated using a miR-21 inhibitor. CONCLUSION: The MEG3/miR-21/ORAI1 axis regulates the manifestation of DN in diabetic mice and MCs, and the miR-21 inhibitor can be a potential therapeutic strategy to alleviate DN, once the presence of such an axis is found in humans.

Vitamin D and Diabetic Kidney Disease.

Vitamin D is a hormone involved in many physiological processes. Its active form, 1,25(OH)2D3, modulates serum calcium-phosphate homeostasis and skeletal homeostasis. A growing body of evidence has demonstrated the renoprotective effects of vitamin D. Vitamin D modulates endothelial function, is associated with podocyte preservation, regulates the renin-angiotensin-aldosterone system, and has anti-inflammatory effects. Diabetic kidney disease (DKD) is a leading cause of end-stage kidney disease worldwide. There are numerous studies supporting vitamin D as a renoprotector, potentially delaying the onset of DKD. This review summarizes the findings of current research on vitamin D and its role in DKD.

Spop ameliorates diabetic nephropathy through restraining NLRP3 inflammasome.

Diabetic nephropathy (DN) is one of the most common causes for end-stage renal disease without effective therapies available. NLR family, pyrin domain-containing 3 (NLRP3) inflammasome possesses a fundamental effect to facilitate the pathogenesis of DN. Unfortunately, how NLRP3 inflammasome is mediated still remains largely unclear. In the present study, an E3 ubiquitin ligase Speckle-type BTB-POZ protein (Spop) was identified as a suppressor of NLRP3 inflammasome. We first showed that Spop expression was extensively down-regulated in kidney of DN patients, which was confirmed in kidney of streptozotocin (STZ)-challenged mice and in high glucose (HG)-stimulated podocytes. Intriguingly, we showed that conditional knockout (cKO) of Spop in podocytes considerably accelerated renal dysfunction and pathological changes in the glomerulus of STZ-induced mice with DN, along with severe podocyte injury. Furthermore, Spop specific ablation in podocytes dramatically facilitated inflammatory response in glomeruli of DN mice via enhancing NLRP3 inflammasome and nuclear factor κB (NF-κB) signaling pathways, which were confirmed in HG-cultured podocytes. Notably, our findings indicated that Spop directly interacted with NLRP3. More importantly, Spop promoted NLRP3 degradation via elevating K48-linked polyubiquitination of NLRP3. Collectively, our findings disclosed a mechanisms through which Spop limited NLRP3 inflammasome under HG condition, and illustrated that Spop may be a novel therapeutic target to suppress NLRP3 inflammasome, contributing to the DN management.

Emodin alleviates high glucose-induced oxidative stress, inflammation and extracellular matrix accumulation of mesangial cells by the circ_0000064/miR-30c-5p/Lmp7 axis.

Emodin has been shown to exert a renoprotective effect in diabetic nephropathy (DN). In this paper, we investigated whether circular RNAs (circRNAs) might be involved in the renoprotective mechanism of emodin in DN. The levels of malondialdehyde (MDA), reactive oxygen species (ROS), superoxide dismutase (SOD), interleukin-1ß (IL-1ß), IL-6 and tumor necrosis factor-α (TNF-α) were measured using the corresponding assay kits. The expression levels of circ_0000064, microRNA (miR)-30c-5p, large multifunctional protease 7 (Lmp7), fibronectin (FN), and collagen type I (Col.1) were gauged by quantitative real-time polymerase chain reaction (qRT-PCR) or western blot. Subcellular localization assay was used to assess the cellular localization of circ_0000064. Targeted relationships among circ_0000064, miR-30c-5p and Lmp7 were confirmed by dual-luciferase reporter, RNA pull-down and RNA immunoprecipitation (RIP) assays. Our data showed the alleviative effect of emodin on HG-induced oxidative stress, inflammation and extracellular matrix (ECM) accumulation in SV-MES13 cells. Circ_0000064 was an importantly downstream effector of emodin function in HG-induced SV40-MES13 cells. Moreover, circ_0000064 directly targeted miR-30c-5p, and circ_0000064 modulated Lmp7 expression through miR-30c-5p. Circ_0000064 silencing alleviated HG-induced cell oxidative stress, inflammation and ECM accumulation via up-regulating miR-30c-5p. The enforced expression of miR-30c-5p attenuated HG-induced oxidative stress, inflammation and ECM accumulation in SV40-MES13 cells by targeting Lmp7. Our findings identified that emodin alleviated HG-induced oxidative stress, inflammation and ECM accumulation in SV40-MES13 cells at least partially by the regulation of the circ_0000064/miR-30c-5p/Lmp7 axis.

TSPAN8 alleviates high glucose-induced apoptosis and autophagy via targeting mTORC2.

TSPAN8 mediates signal transduction from extracellular cues and regulates cell development, activation, growth, and motility. However, whether TSPAN8 is involved in the progression of diabetic nephropathy (DN) remains unclear. This study aimed to explore the potential functional roles of TSPAN8 in regulating autophagy and apoptosis of HK-2 cells induced by high glucose (HG). RT-PCR and western blot analysis (WB) were employed to detect TSPAN8 levels in the blood samples of DN patients as well as in HG-induced HK-2 cells. Cell proliferation of HK-2 cells was examined by CCK-8 assay, and apoptosis was analyzed by flow cytometry. The functional role of TSPAN8 was evaluated by the transfection of TSPAN8 expression plasmid. Results showed that TSPAN8 level was significantly reduced in the blood samples of DN patients and HG-induced HK-2 cell lines. TSPAN8 overexpression rescued HG-induced apoptosis in HK-2 cells. TSPAN8 could form a complex with Rictor and mTORC2. TSPAN8 overexpression suppressed HG-induced autophagy in HK-2 cells, which was dependent on mTOR activity. In conclusion, the present study showed that TSPAN8 mitigates HG-induced autophagy and apoptosis in HK-2 cells, which may serve as candidate target for DN treatment.

The physiological and pathophysiological roles of carbohydrate response element binding protein in the kidney.

Glucose is not only the energy fuel for most cells, but also the signaling molecule which affects gene expression via carbohydrate response element binding protein (ChREBP), a Mondo family transcription factor. In response to high glucose conditions, ChREBP regulates glycolytic and lipogenic genes by binding to carbohydrate response elements (ChoRE) in the regulatory region of its target genes, thus elucidating the role of ChREBP for converting excessively ingested carbohydrates to fatty acids as an energy storage in lipogenic tissues such as the liver and adipose tissue. While the pathophysiological roles of ChREBP for fatty liver and obesity in these tissues are well known, much of the physiological and pathophysiological roles of ChREBP in other tissues such as the kidney remains unclear despite its high levels of expression in them. This review will thus highlight the roles of ChREBP in the kidney and briefly introduce the latest research results that have been reported so far.

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

BACKGROUND: Diabetic nephropathy (DN) is one of the most common and serious complications of diabetes, which can lead to renal failure and fatality. miRNAs are an important class of endogenous non-coding RNAs implicated in a wide range of biological processes and pathological conditions. This study aims to investigate the potential functional roles of miR-543 in DN and its underlying mechanisms. METHODS: qRT-PCR was performed to detect the expression levels of miR-543 and TSPAN8 in kidney tissues of mice with DN. Western blot (WB) was used to measure the protein levels. CCK8 assay was employed to evaluate the proliferation of HK2 cells. Dual luciferase reporter assay was conducted to verify the functional interaction between miR-543 and TSpan8. RESULTS: The downregulation of miR-543 and upregulation of TSPAN8 were observed in kidney tissues of mice with DN. miR-543 mimic significantly decreased cell proliferation and autophagy in high-glucose (HG)-induced HK2 cells, and promoted cell fibrosis. We further identified a putative binding site between miR-543 and TSPAN8, which was validated by Dual luciferase reporter assay. The treatment of miR-543 mimic and miR-543 inhibitor could reduce or increase TSPAN8 protein level respectively. We further showed that the overexpression of TSPAN8 could attenuate HG-induced cell injury by reducing fibrosis and increase autophagy. The effects of miR-543 mimic in proliferation, fibrosis, and autophagy were rescued by TSPAN8 overexpression. CONCLUSIONS: Our study indicate that miR-543 mediates high-glucose induced DN via targeting TSPAN8. Interfering miR-543/TSPAN8 axis could serve as potential approach to ameliorate DN.

LncRNA NEAT2 Modulates Pyroptosis of Renal Tubular Cells Induced by High Glucose in Diabetic Nephropathy (DN) by via miR-206 Regulation.

Patients suffering from terminal-stage diabetic nephropathy (DN) are commonly diagnosed with kidney failure. The condition of DN patients gets generally improved by long-chain noncoding RNA (LncRNA) since it regulates microRNA (miR). The current study analyzes the role played by NEAT2/miR-206 upon cell death of renal tubular epithelial cells (RTECs), high glucose (HG)-induced inflammation and oxidative stress in diabetic nephropathy (DN). The researcher used high glucose (HG) to treat HK-2 cells in in vitro conditions to establish the DN cell model. qRT-PCR was used to confirm the transfection effect whereas the researcher also tested NEAT2, nucleotide-binding oligomerization domain, leucine-rich repeat and pyrin domain containing (NLRP3), caspase-1, interleukin IL-1ß, gasdermin D (GSMDD)-N, and miR-206. To analyze the proteins in caspase-1, IL-1ß, GSMDD-N, and NLRP3, Western blot technique was performed. The technique is also used to observe the pyroptosis. To identify TNF-α, IL-6, MCP-9, NEAT2, miR-206, and NLRP3, dual-luciferase reporter assay was conducted through ELISA kit to emphasize the correlation that exists among the above-mentioned factors. NEAT2 has been confirmed to have bound with miR-206 through double luciferase report experiments as well as RNA immunoprecipitation (RIP). NEAT2, present in HK-2 cells, was induced by HG. So, if NEAT2 is knocked down, it would mitigate TNF-α, IL-6, and MCP-9 as well. Among the HK-2 cells intervened with HG, the overexpressed miR-206 that was transfected into cells was in alignment with the modifications introduced in inflammatory factors and cytokines after NEAT2 is knocked down. The current study concludes that if NEAT2 is upregulated, it has the potential to retreat the inhibition of miR-206 on inflammatory response as well pyroptosis. Further, by targeting miR-206, NEAT2 has the potential to enhance HG-induced HK-2 pyroptosis. This miR-206 is predicted to be a latent target in the clinical treatment of DN.

Knockdown of GPRC5B alleviates the high glucose-induced inflammation and extracellular matrix deposition of podocyte through inhibiting NF-κB pathway.

BACKGROUND: Diabetes is a serious disease that could greatly increase the risk of cardiovascular complications, whereas the underlying pathology of DN is still unknown. GPRC5B is a member of the RAIG subfamily of type 3 (family C) GPCR, and its role in DN is still unclear. OBJECTIVE: To unveil the role of GPRC5B in diabetic nephropathy (DN) progression and investigate the potential signaling pathway. MATERIALS AND METHODS: Podocytes were stimulated with high glucose and expression of GPRC5B was analyzed by qPCR and western blot. Then the level of GPRC5B was depleted by siRNA transfection and inflammatory cytokine level was monitored by ELISA assay. The ECM depostion and the activation of NF-κB pathway were detected by Immunoblot. RESULTS: We investigated the possible role of GPRC5B in the pathology of diabetic nephropathy. We found GPRC5B was highly expressed in high glocuse (HG) induced podocytes. The depletion of GPRC5B inhibited HG induced cell inflammation. In addition, the ablation of GPRC5B suppressed the HG induced ECM deposition. We further found GPRC5B could alleviate the inflammation and extracellular matrix deposition of HG-induced podocytes through NF-κB pathway. CONCLUSION: We therefore thought GPRC5B could serve as a promising target for the treatment of diabetic nephropathy. G-protein-coupled receptors.

Process of Glucose Increases Rather Than Constant High Glucose Was the Main Cause of Abnormal Glucose Induced Glomerulus Epithelial Cells Inflammatory Response.

Abnormal glycemia is frequently along with nephritis, whose pathogenesis is unexplicit. Here, we investigated the effects of abnormal glucose on the renal glomerulus epithelial cells by stimulating immortalized bovine renal glomerulus epithelial (MDBK) cells with five different levels of glucose, including low glucose (2.5 mM for 48 h, LG), normal glucose (5 mM for 48 h, NG), high glucose (25 mM for 48 h, HG), increasing glucose (24 h of 2.5 mM glucose followed by 24 h of 25 mM, IG), and reducing glucose (24 h of 25 mM glucose followed by 24 h of 2.5 mM, RG). The results showed that LG and RG treatments had nonsignificant effects (p > 0.05) on the viability of MDBK cells. HG treatment decreased the viabilities of cells (p < 0.01) without triggering an apparent inflammatory response by activating the nox4/ROS/p53/caspase-3-mediated apoptosis pathway. IG treatment decreased the viabilities of cells significantly (p < 0.01) with high levels of pro-inflammatory cytokines IL-1ß and IL-18 in the supernatant (p < 0.05) by triggering the txnip/nlrp3/gsdmd-mediated pyroptosis pathway. These results indicated that the process of glucose increase rather than the constant high glucose was the main cause of abnormal glucose-induced MDBK cell inflammatory death, prompting that the process of glycemia increases might be mainly responsible for the nephritis in diabetic nephropathy, underlining the importance of glycemic control in diabetes patients.

Effects of glucagon-like peptide-1 receptor agonists (GLP-1RAs) on podocytes, inflammation, and oxidative stress in patients with diabetic nephropathy (DN).

Objectives: To investigate the effects of a glucagon-like peptide-1 receptor agonist (GLP-1RA) liraglutide on podocytes, inflammation, and oxidative stress in patients with diabetic nephropathy (DN). Methods: Eighty-four DN patients treated by the department of endocrinology of the Affiliated Hospital of Hebei University during December 2017 and March 2019 were randomly assigned to a control group and a treatment group (n=42, respectively), with the control group prescribed with conventional DN medications and the treatment group receiving liraglutide treatment in addition to the conventional therapy. The course of treatment lasted for 12 weeks. hemoglobin A1c (HbA1C), body mass index (BMI), total cholesterol (TC), triglyceride (TG), urinary albumin excretion rate (UAER), urine podocalyxin (PCX), urine nephrin, as well as inflammation and oxidative stress markers such as tumor necrosis factor α (TNF-α), monocyte chemotactic protein-1 (MCP-1), glutathione peroxidase (GSH-Px), and malondialdehyde (MDA) were measured pre- and post-treatment for intergroup comparison. Results: After 12 weeks of treatment, HbA1C, BMI, TC, and TG in both groups were reduced in comparison with the pre-treatment levels, with the levels in the treatment group lower than in the control group (p<0.05); reduced levels of UAER, PCX, and nephrin were detected in the two groups, with the treatment group exhibiting a significant reduction in these markers compared with the control group (p<0.05); the 12-week treatment led to decreases in the TNF-α, MCP-1, and MDA levels in both groups, with the decline in the treatment group exceeding that in the control group, whereas both groups had an increased level of GSH-Px, with the level in the treatment group higher than that in the control group, and the differences were statistically significant (p<0.05, respectively). Conclusions: Liraglutide protects the kidneys and improves DN by inhibiting inflammation and oxidative stress, reducing urinary albumin excretion and podocyte damage and supporting renal function in addition to its hypoglycemic properties.

[PK2/PKR1 signaling pathway participates in geniposide protection against diabetic nephropathy in mice].

This study aimed to investigate the effects of geniposide(GP) on the expression of prokineticin(PK2) and prokineticin receptor 1(PKR1) in db/db mice with diabetic nephropathy(DN), so as to explore how the PK2 signaling pathway participated in the pathological changes of DN and whether GP exerted the therapeutic effect through this signaling pathway. Male mice were randomly divided into four groups, namely db/m, db/db, db/db+GP, and db/m+GP groups, with five in each group. The mice in the db/db+GP and db/m+GP groups were gavaged with 150 mg·kg~(-1) GP for eight successive weeks. Afterwards, all the mice were sacrificed and the renal tissues were embedded. The morphological changes in glomerulus and renal tubules were observed by Masson and PAS staining. The expression levels of PK2, PKR1, and Wilm's Tumor Protein 1(WT_1) in podocytes were detected by immunohistochemistry, and the protein expression levels of PK2 and PKR1 in mouse kidney by Western blot. The morphological results showed serious glomerular and tubular fibrosis(Masson), high glomerular and tubular injury score(PAS), increased glomerular mesangial matrix, thickened basement membrane, exfoliated brush border of renal tubules, decreased WT_1 in glomerular podocytes, and massive loss of podocytes in the db/db group. After administration with GP, the glomerular and tubular fibrosis was alleviated, accompanied by improved glomerular basement membrane and renal tubule brush edge, and up-regulated WT_1. As revealed by further protein detection, in the db/db group, the expression levels of PK2 and PKR1 and p-Akt/Akt ratio declined, whereas the ratio of Bax/Bcl-2 rose. Ho-wever, PKR2 and p-ERK/ERK ratio did not change significantly. After administration with GP, the PK2 and PKR1 expression was elevated, and p-Akt/Akt ratio was increased. There was no obvious change in PKR2, Bax/Bcl-2 ratio, or p-ERK/ERK ratio. All these have demonstrated that GP improves the renal damage in DN mice, and PK2/PKR1 signaling pathway may be involved in such protection, which has provided reference for clinical treatment of DN with GP.

Podocyte RNF166 deficiency alleviates diabetic nephropathy by mitigating mitochondria impairment and apoptosis via regulation of CYLD signal.

Diabetic nephropathy (DN) is a major cause of renal failure in diabetic patients. RING-finger protein 166 (RNF166), composed of an N-terminal RING domain and C-terminal ubiquitin interaction motif, plays a critical role in mediating various cellular processes. However, its potential in DN has not been investigated. In the present study, we found that DN patients exhibited significantly increased expression of RNF166 in renal tissues compared with the normal individuals, and abundant RNF166 was detected in podocytes. We then showed that podocyte-conditional RNF166 knockout (RNF166cKO) markedly reduced blood glucose levels and ameliorated renal dysfunction in streptozotocin (STZ)-induced diabetic mice. Additionally, abnormal histological changes and podocyte injury were observed in STZ-induced diabetic mice, while being markedly ameliorated by RNF166cKO. Furthermore, podocyte-specific RNF166 deficiency considerably mitigated apoptosis and mitochondrial impairments in glomeruli podocytes of STZ-challenged mice through suppressing Caspase-3 cleavage and improving mitochondrial fission-associated molecules. In vitro studies further confirmed that high glucose (HG) induced mitochondrial dysfunction, along with enhanced releases of Cyto-c from mitochondria and elevated expression of cleaved Caspase-9, contributing to intrinsic apoptosis in podocytes. Intriguingly, these effects triggered by HG were dramatically ameliorated by RNF166 knockout. Mechanistically, we demonstrated that RNF166 directly interacted with cylindromatosis (CYLD), and negatively regulated CYLD expression. Notably, RNF166 knockout-attenuated mitochondrial damage and apoptosis were mainly through CYLD in podocytes upon HG stimulation. Together, all these findings provided new insights into the novel effects of RNF166 on maintaining mitochondrial function and apoptosis in podocytes during DN progression both in vivo and in vitro through interacting with CYLD, indicating that RNF166/CYLD may be an innovative therapeutic target for developing effective strategy against DN development.

PTPN14 deficiency alleviates podocyte injury through suppressing inflammation and fibrosis by targeting TRIP6 in diabetic nephropathy.

Diabetic nephropathy (DN) is a common complication of diabetes, and a leading cause of end-stage renal disease. However, the pathogenesis that contributes to DKD is still not fully understood. Protein tyrosine phosphatase non-receptor type 14 (PTPN14), a non receptor tyrosine phosphatase, has numerous cellular events, such as inflammation and cell death. But its potential on DKD has not been investigated yet. In this study, we found that PTPN14 expression was markedly up-regulated in kidney samples of DKD patients, which were confirmed in diabetic mice and were clearly localized in glomeruli. The diabetic mouse model was established using streptozotocin (STZ) in wild type (WT) or PTPN knockout (KO) mice. After, STZ challenge, STZ mice displayed improved kidney functions. The results also showed that STZ-induced histological changes and podocyte injury in renal tissues, which were effectively alleviated by PTPN14 deletion. Moreover, PTPN14 deficiency significantly mitigated inflammatory response and fibrosis in glomeruli of STZ-challenged mice through restraining the activation of nuclear factor-κB (NF-κB) and transforming growth factor (TGF)-ß1 signaling pathways, respectively. The inhibitory effects of PTPN14 suppression on inflammation and fibrosis were confirmed in high glucose (HG)-incubated podocytes. We further found that thyroid receptor interactor protein 6 (TRIP6) expression was dramatically up-regulated in glomeruli of STZ-challenged mice, and was abolished by PTPN14 deletion, which was confirmed in HG-treated podocytes with PTPN14 knockdown. Intriguingly, our in vitro studies showed that PTPN14 directly interacted with TRIP6. Of note, over-expressing TRIP6 markedly abrogated the effects of PTPN14 silence to restrict inflammatory response and fibrosis in HG-incubated podocytes. Taken together, our findings demonstrated that targeting PTPN14 may provide feasible therapies for DKD treatment.

Plantamajoside inhibits high glucose-induced oxidative stress, inflammation, and extracellular matrix accumulation in rat glomerular mesangial cells through the inactivation of Akt/NF-κB pathway.

Plantamajoside (PMS) is a phenylpropanoid glycoside that possesses anti-diabetic activity. However, the effect of PMS on diabetic nephropathy (DN) has not been investigated. This study aimed to evaluate the role of PMS in DN and the potential mechanism. The rat glomerular mesangial cells ((MCs) (HBZY-1 cells) were cultured under high glucose (HG) condition or normal condition with or without the treatment of PMS. The results showed that PMS ameliorated the cell injury that was induced by HG in HBZY-1 cells. The HG-caused increases in reactive oxygen species (ROS) and malondialdehyde (MDA) production and decrease in superoxide dismutase (SOD) activity were prevented by PMS. The qRT-PCR and ELISA assays demonstrated an anti-inflammatory activity of PMS, as evidenced by decreased levels of TNF-α, IL-1ß, and IL-6 in HG-induced HBZY-1 cells. Moreover, the increased levels of fibronectin (FN) and collagen type IV (Col IV) in HBZY-1 cells caused by HG were also reduced by PMS treatment. Furthermore, PMS significantly suppressed HG-induced activation of Akt/NF-κB signaling in HBZY-1 cells. Taken together, these findings indicated that PMS alleviated HG-induced injury in HBZY-1 cells through suppressing oxidative stress, inflammatory response, and extracellular matrix (ECM) accumulation via the inactivating Akt/NF-κB pathway. Thus, PMS might possess potential capacity for the treatment of DN.

Potential signaling pathway through which Notch regulates oxidative damage and apoptosis in renal tubular epithelial cells induced by high glucose.

Diabetic nephropathy (DN) is one of the most common and serious complications of diabetes mellitus, and glomerular sclerosis and renal tubular interstitial fibrosis are the main pathological features. Current evidence indicates that the Notch pathway can mediate the impairment of renal tubular function and induce angiogenesis and renal interstitial fibrosis. This study was conducted to explore the potential signaling pathway through which Notch regulates oxidative damage and apoptosis in renal tubular epithelial cells induced by high glucose. mRNA and protein expression levels were assessed using real-time PCR and Western blot, respectively. The protein expression levels of Jaggedl, Notchl, pro-caspase-3, Drpl, and PGC-1α were increased by high glucose, but N-[N-(3,5-difluorohenacetyl)-l-alanyl]-S-phenylglycine tert-butyl ester (DAPT; an inhibitor of the Notch signaling pathway) reversed these effects. Furthermore, DAPT reduced the mRNA expression of Jaggedl, Notchl, MnSOD2, Drpl, and PGC-1α in renal tubular epithelial cells induced by high glucose. In conclusion, the Notch signaling pathway may regulate oxidative damage and apoptosis in renal tubular epithelial cells induced by high glucose by regulating mitochondrial dynein and biogenesis genes, which can accelerate renal interstitial fibrosis in DN. The Notch signaling pathway might be a potential therapeutic target for DN, and DAPT might become a potential drug for the treatment of DN.

Mineralocorticoid Receptor Antagonists-Use in Chronic Kidney Disease.

Mineralocorticoid receptor antagonists (MRA) are drugs with a potentially broad spectrum of action. They have been reported to have healing effects in many diseases, such as chronic heart failure, hypertension, or nephrotic syndrome. Numerous studies suggest that mineralocorticoid receptor activation is pathogenic and a progression factor of chronic kidney disease (CKD); however, results of studies on the use of MRA in the treatment of CKD are inconclusive. Current guidelines recommend against the use of MRA in patients with advanced CKD. Although, there is growing interest on their use in this population due to treatment benefits. In this review, we summarize studies which were purposed to evaluate the impact of MRA therapy on CKD patients. Despite many benefits of this treatment e.g., reducing cardiovascular mortality or alleviating proteinuria, steroidal MRA (such as spironolactone or eplerenone) have a low safety profile. They often lead to hyperkalemia complications which are dangerous in patients with CKD, and diabetic nephropathy, especially in hemodialysis patients. Studies on recently developed nonsteroidal MRA showed that they have fewer side effects. In our review, we discuss steroidal and nonsteroidal MRA treatment effects on the estimated glomerular filtration rate (eGFR), proteinuria, the cardiovascular system, and hyperkalemia in CKD patients. We present new content and recent publications in this field.

Ablation of lncRNA MIAT mitigates high glucose-stimulated inflammation and apoptosis of podocyte via miR-130a-3p/TLR4 signaling axis.

Podocyte injury has been considered as a major contributor to the progression of diabetic nephropathy (DN). Long non-coding RNAs (lncRNAs) are being found to be involved in DN pathogenesis. The current research was designed to elucidate the potential role and latent molecular mechanism of long non-coding RNA MIAT in HG-induced podocyte injury. Our data demonstrated that MIAT expression was substantially elevated but miR-130a-3p was diminished in HG-challenged podocytes. Additionally, lack of MIAT mitigated HG-evoked inflammatory reaction in podocytes as evidenced by the diminished the release of inflammatory mediators TNF-α, IL-6 and IL-1ß. Moreover, depletion of MIAT evidently amplified cell viability and alleviated HG-triggered apoptosis, reflected as the downregulation of Bax expression concomitant with the enhancement of Bcl-2 expression in HG-exposed podocytes. Mechanistically, MIAT effectively modulated TLR4 expression through acting as a competing endogenous sponge of miR-130a-3p, and TLR4 was confirmed as a specific target gene of miR-130a-3p. More importantly, the miR-130a-3p/TLR4 crosstalk contributed to the protective effect of MIAT knockdown on HG-provoked podocyte damage. Collectively, these findings highlighted that blocking MIAT/miR-130a-3p/TLR4 network play vital regulatory roles in mitigating HG-induced inflammation damage and apoptosis, thereby protecting podocyte from HG-stimulated injury, implying that MIAT might be a promising therapeutic strategy for developing effective treatments against DN progression.