Renal Pathological Changes Research Articles

A child with genetic FN1 mutation in the absence of classic glomerulopathy with fibronectin deposits(GFND) findings on biopsy

BackgroundGlomerulopathy with fibronectin deposits (GFND) is a rare autosomal dominant genetic disorder, and proteinuria and hematuria are the most common clinical manifestations. The pathogenesis of this disease is primarily related to mutation of the fibronectin 1 gene. Unfortunately, without specific treatment, the prognosis remains poor. Here we present a case report that investigates the clinical characteristics, renal pathology, and gene testing of childhood GFND.Case presentationA two-year-old child was brought to our hospital for “persistent hematuria for 1 year and 10 months.” The disease onset was at the age of 4 months, with persistent microscopic hematuria accompanied by intermittent gross hematuria, occasionally with proteinuria, and without hypertension or renal failure. The chief complaint was intermittent gross hematuria, without massive proteinuria, hypertension, or renal failure. Family history: The child’s mother had microscopic hematuria, his maternal aunt had nephrotic syndrome due to focal segmental glomerulosclerosis, and his maternal grandmother had end-stage renal disease. No significant pathological changes were found in the renal pathological biopsy of the child under a light microscope. Under the electron microscope, the basement membrane was found to be of uneven thickness, ranging from 150 to 400 nm. The stratum compactum of the basement membrane was thickened, with a small part showing tear-like and cobweb-like morphology. No electron-dense deposits were found. The renal tubular epithelial cells were vacuolated, and there were no unique pathological changes in the renal interstitium. Immunofluorescence showed that IgG, IgM, IgA, C3, and C1q were all negative. Alport syndrome was preliminarily considered. However, exome sequencing revealed a mutated site in the fibronectin 1 gene. The child’s mother was the carrier of the pathogenic gene and the final diagnosis was GFND.ConclusionsFibronectin deposition is a typical pathological change in GFND, and the disease progresses slowly to end-stage renal disease. There is no specific treatment so far, and the prognosis is poor. The early onset of childhood patients may not show typical renal pathological changes, but only changes in the thickness of basement membrane, etc. Genome sequencing technology may helpful for the early diagnosis of GFND.

Deletion of microRNA-183-96-182 Cluster in Lymphocytes Suppresses Anti-DsDNA Autoantibody Production and IgG Deposition in the Kidneys in C57BL/6-Faslpr/lpr Mice.

Dysregulated miRNAs have been implicated in the pathogenesis of systemic lupus erythematosus (SLE). Our previous study reported a substantial increase in three miRNAs located at the miR-183-96-182 cluster (miR-183C) in several autoimmune lupus-prone mice, including MRL/lpr and C57BL/6-lpr (B6/lpr). This study reports that in vitro inhibition of miR-182 alone or miR-183C by specific antagomirs in activated splenocytes from autoimmune-prone MRL/lpr and control MRL mice significantly reduced lupus-related inflammatory cytokines, interferon-gamma (IFNγ), and IL-6 production. To further characterize the role of miR-182 and miR-183C cluster in vivo in lupus-like disease and lymphocyte phenotypes, we used hCD2-iCre to generate B6/lpr mice with conditional deletion of miR-182 or miR-183C in CD2+ lymphocytes (miR-182−/−B6/lpr and miR-183C−/-B6/lpr). The miR-182−/−B6/lpr and miR-183C−/−B6/lpr mice had significantly reduced deposition of IgG immunocomplexes in the kidney when compared to their respective littermate controls, although there appeared to be no remarkable changes in renal pathology. Importantly, we observed a significant reduction of serum anti-dsDNA autoantibodies in miR-183C−/−B6/lpr mice after reaching 24 weeks-of age compared to age-matched miR-183Cfl/flB6/lpr controls. In vitro activated splenocytes from miR-182−/−B6/lpr mice and miR-183C−/−B6/lpr mice showed reduced ability to produce lupus-associated IFNγ. Forkhead box O1(Foxo1), a previously validated miR-183C miRNAs target, was increased in the splenic CD4+ cells of miR-182−/−B6/lpr and miR-183C−/−B6/lpr mice. Furthermore, in vitro inhibition of Foxo1 with siRNA in splenocytes from miR-182−/−B6/lpr and miR-183C−/-B6/lpr mice significantly increased IFNγ expression following anti-CD3/CD28 stimulation, suggesting that miR-182 and miR-183C miRNAs regulate the inflammatory IFNγ in splenocytes via targeting Foxo1. The deletion of either miR-182 alone or the whole miR-183C cluster, however, had no marked effect on the composition of T and B cell subsets in the spleens of B6/lpr mice. There were similar percentages of CD4+, CD8+, CD19+, as well as Tregs, follicular helper T (TFH), germinal center B (GCB), and plasma cells in the miR-183C−/−B6/lpr and miR-182−/−B6/lpr mice and their respective littermate controls, miR-183Cfl/flB6/lpr and miR-182fl/flB6/lpr mice. Together, our data demonstrate a role of miR-183C in the regulation of anti-dsDNA autoantibody production in vivo in B6/lpr mice and the induction of IFNγ in in vitro activated splenocytes from B6/lpr mice.

Bisdemethoxycurcumin Attenuated Renal Injury via Activation of Keap1/Nrf2 Pathway in High-Fat Diet-Fed Mice.

Bisdemethoxycurcumin (BDMC), a principal and active component of edible turmeric, was previously found to have beneficial effects on metabolic diseases. Chronic kidney disease (CKD) may benefit from its potential therapeutic use. Using a high-fat diet (HFD)-fed mouse model, we examined the effects of BDMC on renal injury and tried to determine how its associated mechanism works. A number of metabolic disorders are significantly improved by BDMC, including obesity, hyperglycemia, hyperinsulinemia, hyperlipidemia and inflammation. Further research on renal histopathology and function showed that BDMC could repair renal pathological changes and enhance renal function. Moreover, decreased serum malondialdehyde (MDA), elevated superoxide dismutase (SOD) activity, and the inhibition of renal reactive oxygen species (ROS) overproduction revealed the alleviation of oxidative stress after BDMC administration. In addition, renal Kelch-like ECH-associated protein 1/nuclear factor erythroid 2-related factor 2 (Keap1/Nrf2) pathway was activated in BDMC-treated mice. In conclusion, these findings demonstrated BDMC as a potential therapy for HFD-induced CKD via the activation of the Keap1/Nrf2 pathway.

The kidney-expressed transcription factor ZKSCAN3 is dispensable for autophagy transcriptional regulation and AKI progression in mouse

Acute kidney injury (AKI) is a common clinical disease that can cause serious harm to the kidneys, but it has no effective treatment till now. The modulation of autophagy pathway regulation is considered a potentially effective therapeutic approach in AKI prevention and treatment. ZKSCAN3 has been shown to be an important transcription factor that negatively regulates autophagy activity in cancer tissues. In order to determine whether autophagy could be activated by knocking out ZKSCAN3 to exert the renal protective effect of autophagy, we constructed AKI models with Zkscan3 knockout (KO) mice and detected renal pathological changes and renal function changes as well as autophagy-related indicators. We found that Zkscan3 KO had no significant effect on kidney development. Besides, no significant changes in autophagy activity were observed under normal physiological or AKI conditions. In non-tumor tissues, ZKSCAN3 did not mediate transcriptional regulation of autophagy-related genes. These findings suggest that because ZKSCAN3 may not function in the transcriptional regulation of autophagy-related genes in non-tumor tissues, it may not be used as a therapeutic target for AKI.

Inhibition of polycomb repressive complex 2 by targeting EED protects against cisplatin-induced acute kidney injury.

Polycomb repressive complex 2 (PRC2) is a multicomponent complex with methyltransferase activity that catalyzes trimethylation of histone H3 at lysine 27 (H3K27me3). Interaction of the epigenetic reader protein EED with EZH2, a catalytic unit of PRC, allosterically stimulates PRC2 activity. In this study, we investigated the role and underlying mechanism of the PRC2 in acute kidney injury (AKI) by using EED226, a highly selective PRC2 inhibitor, to target EED. Administration of EED226 improved renal function, attenuated renal pathological changes, and reduced renal tubular cell apoptosis in a murine model of cisplatin‐induced AKI. In cultured renal epithelial cells, treatment with either EED226 or EED siRNA also ameliorated cisplatin‐induced apoptosis. Mechanistically, EED226 treatment inhibited cisplatin‐induced phosphorylation of p53 and FOXO3a, two transcriptional factors contributing to apoptosis, and preserved expression of Sirtuin 3 and PGC1α, two proteins associated with mitochondrial protection in vivo and in vitro. EED226 was also effective in enhancing renal tubular cell proliferation, suppressing expression of multiple inflammatory cytokines, and reducing infiltration of macrophages to the injured kidney. These data suggest that inhibition of the PRC2 activity by targeting EED can protect against cisplatin‐induced AKI by promoting the survival and proliferation of renal tubular cells and inhibiting inflammatory response.

New indication of Chuankezhi injection for steroid-resistant focal segmental glomerulosclerosis and its mechanism of action.

BackgroundChuankezhi (CKZ) injection is a traditional Chinese medicine (TCM) injection extracted from Chinese herbs Epimedium sagittatum (Yin Yang Huo) and Morinda officinalis (Bai Ji Tian). Studies have shown that CKZ has a positive effect on improving diabetic nephropathy and regulating immune function. Focal segmental glomerulosclerosis (FSGS) is a kind of refractory nephropathy, which has been confirmed as closely associated with immunity. Whether CKZ is effective against FSGS and how it works warrant further study. This study aimed to verify the efficacy of CKZ in rats with steroid-resistant (SR) FSGS and explore its mechanism of action.MethodsWe established an SR FSGS model in male Sprague Dawley (SD) rats by injecting adriamycin into the tail vein. Based on group intervention and comparison, the primary efficacy parameters of FSGS were observed, including general condition, 24-hour urine protein, serum albumin, cholesterol, triglyceride, and renal pathological changes. Network pharmacological analysis and molecular docking were used to predict the mechanism of action of CKZ. Finally, we used quantitative polymerase chain reaction (qPCR) and western blot (WB) to detect messenger RNA (mRNA) expression and protein phosphorylation at specific targets in rat kidney tissue to validate the predicted results.ResultsIntramuscular injection of CKZ had a dose-dependent effect in SR FSGS model rats, including lowering urine protein, increasing serum albumin, lowering cholesterol and triglyceride, and treating pathological lesions in the kidney. Network pharmacological analysis and Molecular docking revealed that 5 active components (Icariin, Icariside II, Epimedin C, Icaritin, and Noricaritin) might be the critical components. The findings also revealed that Akt was perhaps the critical target gene, the PI3K-Akt signaling pathway was perhaps the critical pathway, and reversible protein phosphorylation was probably the critical biological process. The qPCR and WB analyses showed that CKZ significantly increased the relative mRNA expression and protein phosphorylation of PI3K and Akt, respectively.ConclusionsThis study showed that intramuscular injection of CKZ has a significant therapeutic effect in SR FSGS rats, which may be associated with the activation of PI3K-Akt signaling by CKZ.

Berberine protects diabetic nephropathy by suppressing epithelial-to-mesenchymal transition involving the inactivation of the NLRP3 inflammasome

Accumulating evidence has implicated that berberine (BBR) has a beneficial effect on diabetic kidney disease (DKD), but its mechanism is not clear. The aim of this study was to assess whether berberine could alleviate tubulointerstitial fibrosis and attenuate epithelial-to-mesenchymal transition (EMT) and its possible molecular mechanism. High-fat diet (HFD) followed by injection of STZ was used to induce diabetic rats in vivo. After the onset of diabetes, rats were treated with either BBR or saline for 12 weeks. In vitro, the human renal proximal tubular epithelial cell line (HK-2) was exposed to high glucose, with or without BBR. The influence of berberine on renal tubulointerstitial histological changes, markers of epithelial-to-mesenchymal transition (EMT) and (NOD-like receptor pyrin domain-containing protein 3) NLRP3 inflammasome expression were examined. Results showed that in vivo, BBR could significantly ameliorate microalbumin and renal pathologic changes in diabetic rats. Immunofluorescence showed that BBR could inhibit EMT. Furthermore, BBR could down-regulate the level of the NLRP3 inflammasome in diabetic rats. Consistently, in vitro, BBR suppressed high glucose-induced EMT and activation of NLRP3 inflammasome in HK-2. Our study demonstrated that BBR could inhibit high glucose-induced EMT and renal interstitial fibrosis by suppressing the NLRP3 inflammasome. BBR might be used as a novel drug to ameliorate tubulointerstitial fibrosis in DKD.

Glabridin, a bioactive component of licorice, ameliorates diabetic nephropathy by regulating ferroptosis and the VEGF/Akt/ERK pathways

BackgroundGlabridin (Glab) is a bioactive component of licorice that can ameliorate diabetes, but its role in diabetic nephropathy (DN) has seldom been reported. Herein, we explored the effect and underlying mechanism of Glab on DN.MethodsThe bioactive component-target network of licorice against DN was by a network pharmacology approach. The protective effect of Glab on the kidney was investigated by a high-fat diet with streptozotocin induced-diabetic rat model. High glucose-induced NRK-52E cells were used for in vitro studies. The effects of Glab on ferroptosis and VEGF/Akt/ERK pathways in DN were investigated in vivo and in vitro using qRT-PCR, WB, and IHC experiments.ResultsBioinformatics analysis constructed a network comprising of 10 bioactive components of licorice and 40 targets for DN. 13 matching targets of Glab were mainly involved in the VEGF signaling pathway. Glab treatment ameliorated general states and reduced FBG, HOMA-β, and HOMA-insulin index of diabetic rats. The renal pathological changes and the impaired renal function (the increased levels of Scr, BUN, UREA, KIM-1, NGAL, and TIMP-1) were also improved by Glab. Moreover, Glab repressed ferroptosis by increasing SOD and GSH activity, and GPX4, SLC7A11, and SLC3A2 expression, and decreasing MDA and iron concentrations, and TFR1 expression, in vivo and in vitro. Mechanically, Glab significantly suppressed VEGF, p-AKT, p-ERK1/2 expression in both diabetic rats and HG-induced NRK-52E cells.ConclusionsThis study revealed protective effects of Glab on the kidney of diabetic rats, which might exert by suppressing ferroptosis and the VEGF/Akt/ERK pathway.

Protection Against Post-resuscitation Acute Kidney Injury by N-Acetylcysteine via Activation of the Nrf2/HO-1 Pathway.

Background and ObjectiveAcute kidney injury (AKI), the common complication after cardiopulmonary resuscitation (CPR), seriously affects the prognosis of cardiac arrest (CA) patients. However, there are limited studies on post-resuscitation AKI. In addition, it has been demonstrated that N-acetylcysteine (N-AC) as an ROS scavenger, has multiorgan-protective effects on systemic and regional ischaemia-reperfusion injuries. However, no studies have reported its protective effects against post-resuscitation AKI and potential mechanisms. This study aimed to clarify the protective effects of N-AC on post-resuscitation AKI and investigate whether its potential mechanism was mediated by activating Nrf-2/HO-1 pathway in the kidney.MethodsWe established cardiac arrest models in rats. All animals were divided into four groups: the sham, control, N-AC, and ZnPP groups. Animals in each group except for the ZnPP group were assigned into two subgroups based on the survival time: 6 and 48 h. The rats in the control, N-AC, and ZnPP groups underwent induction of ventricular fibrillation (VF), 8 min untreated VF and cardiopulmonary resuscitation. Renal function indicators, were detected using commercial kits. Renal pathologic changes were assessed by haematoxylin–eosin (HE) staining. Oxidative stress and inflammatory responses were measured using the corresponding indicators. Apoptosis was evaluated using terminal uridine nick-end labeling (TUNEL) staining, and expression of proteins associated with apoptosis and the Nrf-2/HO-1 pathway was measured by western blotting.ResultsN-AC inhibited post-resuscitation AKI. We observed that N-AC reduced the levels of biomarkers of renal function derangement; improved renal pathological changes; and suppressed apoptosis, oxidative stress, and inflammatory response. Additionally, the production of ROS in the kidneys markedly decreased by N-AC. More importantly, compared with the control group, N-AC further upregulated the expression of nuclear Nrf2 and endogenous HO-1 in N-AC group. However, N-AC-determined protective effects on post-resuscitation AKI were markedly reversed after pretreatment of the HO-1 inhibitor zinc protoporphyrin (ZnPP).ConclusionsN-AC alleviated renal dysfunction and prolonged survival in animal models of CA. N-AC partially exerts beneficial renal protection via activation of the Nrf-2/HO-1 pathway. Altogether, all these findings indicated that N-AC as a common clinical agent, may have the potentially clinical utility to improve patients the outcomes in cardiac arrest.

Allograft inflammatory factor-1 enhances inflammation and oxidative stress via the NF-κB pathway in diabetic kidney disease

Inflammation and glomerular endothelial dysfunction promote diabetic kidney disease (DKD) progression, but the mechanisms are not fully understood. Allograft inflammatory factor-1 (AIF-1) is a protein that regulates inflammatory reactions and immune responses. This study aimed to explore the mechanism of AIF-1 in a DKD animal model and mouse renal glomerular endothelial cells (MRGECs). We injected AIF-1-shRNA into the tail vein to knockdown AIF-1 in db/db mice. Metabolic index, renal pathological changes and inflammatory factors were measured in each group. Lentiviral transfection was used to overexpress AIF-1 in MRGECs. Inflammatory factors, oxidative stress and nuclear factor-κB (NF-κB) pathway-related proteins were examined. AIF-1 expression was upregulated in glomerular endothelial cells in renal tissues of db/db mice. Knockdown of AIF-1 reversed kidney injury and renal inflammation in db/db mice. In a 30 mM high-glucose environment, overexpression of AIF-1 in MRGECs activated the NF-κB pathway and induced inflammation and oxidative stress. Moreover, this damage could be attenuated by the addition of an NF-κB inhibitor (BAY 11–7082). In conclusion, AIF-1 facilitates glomerular endothelial cell inflammation and oxidative stress in DKD via the NF-κB signaling pathway. Our results provide evidence for the molecular mechanism of DKD and may offer a potential target for DKD treatment.

Qinghao-Biejia Herb Pair Alleviates Pristane-Induced Lupus-Like Disease and Associated Renal and Aortic Lesions in ApoE-/- Mice.

Backgroud: Systemic lupus erythematosus (SLE) is a chronic autoimmune disease involving multiple systems with a high prevalence of nephritis and atherosclerosis. Jieduquyuziyin prescription is a famous prescription with immune modulating and inflammation controlling effects, which is efficacious in the treatment of SLE. The most critical herbs in this prescription are Qinghao and Biejia. The aim of this study was to evaluate the therapeutic effect of Qinghao-Biejia herb hair (QB) on mice with SLE combined with atherosclerosis. Materials and Methods: The effect of QB (identification using UPLC-TOF-MS) was assessed in female ApoE−/− mice intraperitoneally injected with 0.5 ml of pristane. Serum autoantibodies and lipid metabolic parameters were tested every 4 weeks, and spleen index, serum inflammatory biomarkers, renal injury, and aortic injury were observed after 16 weeks. The expression of signaling pathway in kidney tissues was observed by RT-qPCR and Western blot. Results: The mice of QB-treated group exhibited a significant reduced serum autoantibodies level, urine protein, and renal immune complex deposition. QB treatment reduced the levels of inflammatory cytokines and improved the renal pathological changes. In addition, there was a reduction in aortic atheromatous plaque and some improvement in dyslipidemia. Moreover, QB suppressed the expression of HMGB1, TLR4, and MyD88 to some extent. Conclusion: The present study implied that QB has clear efficacy for the treatment of SLE combined with atherosclerosis, and that inhibition of the HMGB1/TLR4 signaling pathway may be one of the therapeutic targets of QB for SLE combined with atherosclerosis.

Effects of prolonged cold ischemia on the DCD kidney function and Inflammasome expression in rat kidney transplants

BackgroundAcute kidney injury (AKI) is the main reason for the bad outcome of the donation of circulatory death (DCD) kidney after transplantation. Prolonged cold storage (CS) is a risk factor for the occurrence of the delayed graft function in DCD kidney. The protein NLR-domain containing receptor 3 (NLRP3) plays a crucial role in renal ischemia reperfusion injury by triggering inflammasome formation. Herein, we investigated whether the NLRP3 signal participate in the CS-induced damage of DCD kidney in rat kidney transplantation models. Materials and methodsDCD kidney and living donor (LD) kidney of SD rats were preserved in UW solution at 4 °C for 2 h or 18 h, and then transplanted into syngeneic recipient. Thus, the animals were randomly divided into 4 groups: 2-h LD group, 2-h DCD group, 18-h LD group and 18-h DCD group. The renal function and pathological changes were determined. The expressions of NLRP3 and inflammatory factor IL-1β were assessed. The concentration of ferrous iron (Fe2+) was analyzed both in kidneys and in the preservation solution. The renal morphological changes were examined by hematoxylin eosin staining. ResultsOur results showed that the levels of Cr and BUN were higher in 18-h LD group as compared to the 2-h LD group, which were remarkably increased in 18-h DCD group. The expression levels of NLRP3 and IL-1β were increased by 18-h CS compared to 2-h CS in both LD kidney and DCD kidney. In addition, the Fe2+ concentration has significantly increased in 18-h LD group than that in 2-h LD group, and the elevation of Fe2+ was more remarkable in DCD kidneys. ConclusionIn conclusion, our study demonstrated that prolonged hypothermic storage of DCD kidney deteriorated the graft function via the increased Fe2+ concentration, which was associated with the upregulation of NLRP3 expression.

Jiedu Tongluo Baoshen formula enhances podocyte autophagy and reduces proteinuria in diabetic kidney disease by inhibiting PI3K/Akt/mTOR signaling pathway

Ethnopharmacological relevanceTraditional Chinese medicine (TCM) has been applied to diabetic kidney disease (DKD). A large number of animal trials each year focus on TCM for DKD, but the evidence for these preclinical studies is not clear. Aim of the studyThe aim of this study was to study the therapeutic effect of Jiedu Tongluo Baoshen formula (JTBF) on DKD proteinuria and renal protection. At the same time, it is verified that JTBF can reduce podocyte injury by enhancing autophagy function, and then achieve the effect of proteinuria. Materials and methodsWe use high performance liquid chromatography to detect and analyze the fingerprint of JTBF to find the chemical composition. Subsequently, we constructed a DKD rat model induced by high-fat diet and streptozocin (HFD + STZ). Urine and blood biochemical automatic analyzer were used to detect 24-h urine protein quantification (24 h-UP) and renal function. The renal pathological changes were observed by H&E and transmission electron microscopy (TEM), and the levels of autophagy-related proteins and mRNA in podocytes were detected by immunohistochemistry, RT-qPCR and Western Blot. The chemical composition of JTBF was screened from traditional Chinese medicine systems pharmacol (TCMSP) and PubChem databases, and the potential targets and associated pathways of JTBF were predicted using kyoto encyclopedia of genes and genomes (KEGG) and protein-protein interaction (PPI) network analysis in network pharmacology, and confirmed in animal experiments and histopathological methods. ResultsWe discovered 77 active ingredients of JTBF. Through animal experiments, it was found that JTBF reduced 24 h-UP and promoted the expression of podocin, nephrin, and WT-1 in podocytes, thereby reducing podocyte damage. At the same time, JTBF activates the expression of podocyte autophagy-related proteins (beclin-1, LC3 and P62). Subsequently, through network pharmacology predictions, 208 compounds were obtained from JTBF, and phosphatidylinositol 3-kinase/protein kinase B/mammalian target of rapamycin (PI3K/Akt/mTOR) was a potential signal pathway. JTBF was obtained in DKD rat kidney tissue to inhibit the expression of PI3K, Akt and mTOR related proteins. ConclusionsJTBF enhance podocyte autophagy to reduce podocyte damage, thereby effectively treating DKD proteinuria and protecting kidney function.

Fraxin Promotes the Activation of Nrf2/ARE Pathway via Increasing the Expression of Connexin43 to Ameliorate Diabetic Renal Fibrosis.

Diabetic nephropathy (DN) is quickly becoming the largest cause of end-stage renal disease (ESRD) in diabetic patients, as well as a major source of morbidity and mortality. Our previous studies indicated that the activation of Nrf2/ARE pathway via Connexin43 (Cx43) considerably contribute to the prevention of oxidative stress in the procession of DN. Fraxin (Fr), the main active glycoside of Fraxinus rhynchophylla Hance, has been demonstrated to possess many potential pharmacological activities. Whereas, whether Fr could alleviate renal fibrosis through regulating Cx43 and consequently facilitating the activation of Nrf2/ARE pathway needs further investigation. The in vitro results showed that: 1) Fr increased the expression of antioxidant enzymes including SOD1 and HO-1 to inhibit high glucose (HG)-induced fibronectin (FN) and inflammatory cell adhesion molecule (ICAM-1) overexpression; 2) Fr exerted antioxidant effect through activating the Nrf2/ARE pathway; 3) Fr significantly up-regulated the expression of Cx43 in HG-induced glomerular mesangial cells (GMCs), while the knock down of Cx43 largely impaired the activation of Nrf2/ARE pathway induced by Fr; 4) Fr promoted the activation of Nrf2/ARE pathway via regulating the interaction between Cx43 and AKT. Moreover, in accordance with the results in vitro, elevated levels of Cx43, phosphorylated-AKT, Nrf2 and downstream antioxidant enzymes related to Nrf2 were observed in the kidneys of Fr-treated group compared with model group. Importantly, Fr significantly improved renal dysfunction pathological changes of renal fibrosis in diabetic db/db mice. Collectively, Fr could increase the Cx43-AKT-Nrf2/ARE pathway activation to postpone the diabetic renal fibrosis and the up-regulation of Cx43 is probably a novel mechanism in this process.

Hirudin attenuates puromycin aminonucleoside-induced glomerular podocyte injury by inhibiting MAPK-mediated endoplasmic reticulum stress.

Damage to podocytes is an important determinant of renal pathology. The puromycin aminonucleoside (PAN) mice nephropathy model is commonly used in the study of renal disease with podocyte injury. Hirudin has a broad nephroprotective effect and has been shown to treat renal interstitial fibrosis in previous studies. Mice were given PAN by gavage to prepare animal models, and MPC5 cells were incubated with PAN in vitro. Twenty-four hours urine was collected for analysis of urinary protein levels. Renal pathological changes were observed by hematoxylin and eosin staining. Immunofluorescence detection of nephrin in kidney tissues and cells. Apoptosis was analyzed with over TUNEL. Cytoskeleton, endoplasmic reticulum stress (ERS), p38 MAPK signaling, and apoptosis-related proteins were assessed by western blot analysis. The data suggested that hirudin attenuated reduced renal injury and increased urine protein in PAN mice. Hirudin also attenuated cytoskeletal protein (synaptopodin, nephrin, and podocin) disruption, ERS activation, and apoptosis in PAN mice and PAN-induced podocytes. In addition, hirudin inhibited the expression of p38 MAPK signaling key proteins upregulated by PAN, thereby suppressing ERS. The p38 MAPK agonist was able to partially antagonize the inhibition of p38 MAPK signaling by hirudin in PAN-induced podocytes, thereby reactivating the ERS inhibited by hirudin, promoting cytoskeletal protein degradation and increasing the level of apoptosis. In conclusion, hirudin could decrease podocyte injury by inhibiting p38 MAPK signaling-mediated ERS, resulting in the protection of the kidney from PAN damage. These findings may provide an experimental basis for hirudin treatment of podocyte injury diseases.

Potential Therapeutic Effect and Mechanisms of Mesenchymal Stem Cells-Extracellular Vesicles in Renal Fibrosis.

Renal fibrosis (RF) is central pathological pathway for kidney diseases, with the main pathological features being the aberrant accumulation of myofibroblasts that produce accumulation of extracellular matrix in the renal interstitium and glomeruli. Acute kidney injury (AKI) and chronic kidney disease (CKD) are associated with RF. Current treatment strategies for RF are ineffective. Mesenchymal stem cells (MSCs) have been found to be able to treat organ fibrosis including RF, but they have some safety problems, such as cell rejection, carcinogenicity, and virus contamination, which limit the application of MSCs. However, current studies have found that MSCs may exert their therapeutic effect by releasing extracellular vesicles (EVs). MSC-EVs can transfer functional proteins and genetic material directly to the recipient cells. As non-cell membrane structures, MSC-EVs have the advantages of low immunogenicity, easy preservation, and artificial modification, but do not have the characteristics of self-replication and ectopic differentiation. Therefore, EVs are safer than MSCs for treatment, but might be less effective than MSCs. Recent studies have also found that MSC-EVs can improve renal function and pathological changes of RF. Thus, this review summarizes the therapeutic effect of MSC-EVs on RF and the mechanisms that have been discovered so far, so as to provide a theoretical basis for the further study of the role of MSC-EVs in treating RF diseases.

Meloxicam Alleviates Sepsis-Induced Kidney Injury by Suppression of Inflammation and Apoptosis via Upregulating GPNMB.

Objective At present, renal injury caused by sepsis seriously endangers the health of patients. Our paper proposed to study the protective effects of meloxicam (Mel) in sepsis-induced acute kidney injury (SAKI) and the underlying mechanisms. Methods The in vitro and in vivo models of SAKI were established using lipopolysaccharide (LPS). Mel was injected intraperitoneally at 60 mg/kg into male C57BL/6 mice 4 hours before LPS injection (10 mg/kg). The HK-2 cells were treated with LPS (1 μg/mL) and Mel (40 μM). The renal function and renal pathological changes as well as renal inflammation and apoptosis were detected in SAKI mice. The inflammation and apoptosis of HK-2 cells induced by LPS were also detected. Results The treatment of Mel significantly decreased the elevated levels of serum creatinine (Scr) and blood urea nitrogen (BUN) in SAKI mice. In addition, the results of HE staining suggested that Mel significantly reduced kidney damage in SAKI mice. Consistently, Mel reduced the expression of LPS-induced kidney injury markers (NGAL and KIM-1). Moreover, LPS induced the expression of inflammatory cytokines (IL-1β, IL-6, and TNF-α) in the kidney, which can be reduced by Mel. Furthermore, Mel effectively reduced the number of apoptotic cells and inhibited the expression of proapoptotic-related proteins (cleaved Caspase-3 and Bax) but increased the antiapoptotic-related protein (Bcl-2) in the kidneys of SAKI mice. Mechanistically, Mel inhibited the phosphorylation of P65 but induced the phosphorylation of AKT and the expression of glycoprotein B of nonmetastatic melanoma (GPNMB). However, knocking down GPNMB can eliminate the anti-inflammatory and antiapoptotic effects of Mel. Conclusion Mel alleviated sepsis-induced kidney injury by inhibiting kidney inflammation and apoptosis via upregulating GPNMB.

Fufang Zhenzhu Tiaozhi capsule attenuates renal damage by restoring Th17/Treg balance in diabetic db/db mice

ObjectiveTo explore the renal protection effect and mechanism of Fufang Zhenzhu Tiaozhi capsule (FTZ) in diabetic db/db mice in vivo and in vitro. MethodsMale db/m mice were considered as control group, and male db/db mice were considered as diabetic kidney disease (DKD) group, which were administered with different doses of FTZ (FTZ-L, 1 g•kg-1•d-1; FTZ-H, 2 g•kg-1•d-1) and losartan (positive control, 30 mg•kg-1•d-1) treatment for 12 weeks respectively, and then all mice were sacrificed. The high glucose-induced Jurkat T cell was used to evaluate the immune regulatory effect of FTZ in vitro. The renal pathological change was evaluated by H&E method. The levels of serum creatinine (Scr), proteinuria, and urinary albumin-to-creatinine ratio (UACR) were detected by biochemical parameter test kits. The expression levels of fibronectin and collagen IV were detected by immunofluorescence (IF) and immunohistochemistry (IHC). The inflammation factors including TNF-α, TGF-β, IL-6, IL-8, and IL-10 were detected by ELISA kits. The protein expression levels of IL-17A, RORγt, Foxp3, p-NF-κB, p-IκB, NF-κB, and IκB were detected by western blot. The percentage of T helper 17 (Th17) cells and regulatory T (Treg) cells were measured by flow cytometry. ResultsFTZ could significantly alleviate the renal pathological changes and decrease the levels of renal function parameters including Scr, proteinuria, UACR levels, and attenuate the renal inflammation injury by reducing the inflammatory cells infiltration and cytokines (TNF-α, TGF-β, IL-6, and IL-8) secretion, as well as inhibit NF-κB signaling pathway activation and restore the Th17/Treg balance in diabetic db/db mice. Furthermore, FTZ treatment could also decrease the protein levels of RORγt and IL-17A in high glucose-induced Jurkat T cells. ConclusionFTZ exerted protective effects on the kidney in diabetic db/db mice, whose mechanism might be related to regulating the Th17/Treg balance and inhibiting NF-κB signaling pathway.

CCL5 Suppresses Klotho Expression via p-STAT3/DNA Methyltransferase1-Mediated Promoter Hypermethylation.

BackgroundEnhanced inflammation and reduced Klotho are common features in chronic kidney disease (CKD). Inflammation induces DNA hypermethylation. This study assessed the performance of inflammatory marker C-C motif chemokine 5 (CCL5) in epigenetic regulation of Klotho expression.MethodsFifty CKD patients and 25 matched controls were enrolled, and serum CCL5 level, sKlotho level, and DNA methylation were evaluated in these subjects. A renal interstitial fibrosis (RIF) model with CKD was induced in mice via unilateral ureteral obstruction (UUO) in vivo and human proximal tubular epithelial (HK-2) cells treated with CCL5 in vitro. 5-aza-2′-deoxycytidine (5-Aza), a DNA methyltransferase inhibitor was given to UUO mice. Hematoxylin and eosin (HE) and Masson trichrome staining were adopted to evaluate renal pathological changes. Methylation-specific PCR was performed to assess DNA methylation of Klotho promoter in the peripheral blood leucocytes (PBLs) from CKD patients and obstructive kidney from UUO mice. CCL5, Klotho, and DNA methyltransferases (DNMTs) were determined by ELISAs, immunofluorescence, or western blotting. HK-2 cells were exposed to CCL5 with or without 5-Aza and stattic, a p-signal transducer and activator of transcription 3 (STAT3) inhibitor, and expressions of p-STAT3, DNMT1, and Klotho were determined by western blotting.ResultsCCL5 upregulation concomitant with Klotho downregulation in serum and global DNA methylation in PBLs were observed in CKD samples. UUO contributed to severe renal interstitial fibrosis and enhanced expressions of fibrotic markers. Moreover, UUO increased the CCL5 level, induced Klotho promoter methylation, suppressed Klotho level, activated p-STAT3 signaling, and upregulated DNMT1 level. A similar observation was made in HK-2 cells treated with CCL5. More importantly, 5-Aza inhibited UUO-induced Klotho hypermethylation, reversed Klotho, downregulated p-STAT3 expressions, and ameliorated RIF in vivo. The consistent findings in vitro were also obtained in HK-2 cells exposed to 5-Aza and stattic.ConclusionThe CCL5/p-STAT3/DNMT1 axis is implicated in epigenetic regulation of Klotho expression in CKD. This study provides novel therapeutic possibilities for reversal of Klotho suppression by CKD.

The Astragaloside IV Derivative LS-102 Ameliorates Obesity-Related Nephropathy.

BackgroundAstragaloside IV is the most important bioactive component of Radix Astragali. Previous studies have shown that astragaloside IV plays an important role in the control of early- and mid-stage diabetes and late diabetic nephropathy. However, it is disappointing that the in vivo solubility of astragaloside IV and its bioavailability after oral administration are very low. We recently obtained a new water-soluble derivative of astragaloside IV-astragaloside formic acid (LS-102), which has higher bioavailability than the parent compound. In our previous study, we found that there was a significant inflammatory response in the perirenal adipose tissue of mice with obesity-related nephropathy induced by a high-fat diet (HFD), which was related to macrophage infiltration. We hypothesized that in model mice with obesity-related nephropathy, LS-102 effectively regulated the inflammatory response and pathological changes in obesity-related nephropathy through macrophages in perirenal adipose tissue. If this hypothesis is true, the effects of LS-102 and astragaloside IV on TGF-β1/Smad signal transduction will be further investigated.MethodsIn this study, adipose stem cells and an HFD-induced obesity-related nephropathy mouse model were used to observe the regulatory effect of LS-102 on perirenal fat inflammation and the mechanism. Adipose mesenchymal stem cells were extracted from mice that were fed a normal diet and those with obesity-related nephropathy. The effects of LS-102 on the proliferation of two kinds of cells were measured by the CCK-8 method. The levels of tumor necrosis factor-α (TNF-a) and plasminogen activator inhibitor-1 (PAI-1) were measured by ELISA. Obesity-related nephropathy mice were randomly divided into five groups: the HFD group, the LAS group (HFD+low concentration of astragaloside IV [10 mg/kg], intragastrically [ig]), the HAS group (HFD+high concentration of astragaloside IV [40 mg/kg], ig), the L102 group (HFD+low concentration of LS-102 [10 mg/kg], ig) and the H102 group (HFD+high concentration of LS-102 [40 mg/kg], ig). Body weight was measured, and the levels of serum glucose, high-density lipoprotein (HDL), low-density lipoprotein (LDL), triglyceride (TG), total cholesterol (TC), serum creatinine (Crea) and blood urea were measured. The kidneys were stained with HE, PAS and Masson’s trichrome. Perirenal adipose tissue was harvested to examine the expression of CD68, LCA, CD11C, TNF-a, TGF-β1, Fn1, Smad2, Smad3, Smad4, and Smad7 by immunohistochemical staining, and F4/80 was examined by immunofluorescence staining.ResultsLS-102 significantly inhibited the in vitro secretion of TNF-a and PAI-1 by adipose stem cells in a concentration-dependent manner (P < 0.05). In vivo, the body weights in the LAS group, HAS group, L102 group and H102 group were significantly lower than those in the HFD group (P < 0.05). Except for that in the HFD group, the volume of perirenal adipocytes in the other groups was small and uniform (P < 0.05). Compared with the LAS, HAS, L102 and H102 groups, the HFD group had a larger glomerular cross-sectional area, proliferation of mesangial cells and the mesangial matrix, and increased matrix area/glomerular area (P < 0.05). The effect of LS-102 was better than that of astragaloside IV at the same concentration (P < 0.05). Compared with those in the HFD group, glucose, HDL-C, LDL-C and urea levels in the LAS group, HAS group, L102 group and H102 group were significantly decreased (P < 0.05). The expression of F4/80, CD68, LCA, TNF-a, CD11C, and PAI-1 in perirenal adipose tissue in the HFD group was significantly higher than that in the LAS group, HAS group, L102 group and H102 group (P < 0.05). Compared with those in the HFD group, the expression levels of TGF-β1 and Fn1 in the HAS group, L102 group and H102 group were significantly increased (P < 0.05). Compared with the HFD group, the HAS group, L102 group and H102 group had decreased immunopositive rates of Smad2, Smad3 and Smad4 (P < 0.05). At the same concentration, the effect of LS-102 was better than that of astragaloside IV (P < 0.05). There was no significant difference in the expression of Smad7 among the different experimental groups (P > 0.05).ConclusionAstragaloside IV and LS-102 improved the inflammatory reaction in perirenal adipose tissue and renal pathological changes in obesity-related nephropathy model mice and inhibited the TGF-β1/Smad signaling cascade. At the same concentration, the effect of LS-102 was better than that of astragaloside IV. These results suggest that LS-102 has a better protective effect against obesity-related nephropathy. LS-102 may be a new type of traditional Chinese medicine for the clinical treatment of obesity and its related metabolic diseases.