Sanqi oral solution ameliorates renal damage and restores podocyte injury in experimental membranous nephropathy via suppression of NFκB

Sanqi oral solution ameliorates renal fibrosis by suppressing fibroblast activation via HIF-1α/PKM2/glycolysis pathway in chronic kidney disease

ETHNOPHARMACOLOGICAL RELEVANCE

Sanqi oral solution (SQ) is a traditional Chinese patent medicine, widely used to treat chronic kidney diseases (CKD) in the clinic in China. Previous studies have confirmed its anti-renal fibrosis effect, but the specific pharmacological mechanism is still unclear.

AIM OF THE STUDY

Focusing on energy metabolism in fibroblasts, the renoprotective mechanism of SQ was investigated in vitro and in vivo.

METHODS

Firstly, the fingerprint of SQ was constructed and its elementary chemical composition was analyzed. In the 5/6Nx rats experiment, the efficacy of SQ on the kidney was evaluated by detecting serum and urine biochemical indexes and pathological staining of renal tissues. Lactic acid and pyruvic acid levels in serum and renal tissues were detected. PCNA protein expression in kidney tissue was detected by immunofluorescence assay and Western blot. Expression levels of HIF-1α, PKM2 and HK2 were determined by immunohistochemistry, Western blot or RT-qPCR assay. In addition, the effect of SQ intervention on cell proliferation and glycolysis was evaluated in TGF-β1-induced NRK-49F cells, and the role of SQ exposure and HIF-1α/PKM2/glycolysis pathway were further investigated by silencing and overexpressing HIF-1α gene in NRK-49F cells.

RESULTS

In 5/6 Nx rats, SQ effectively improved renal function and treated renal injury. It reduced the levels of lactic acid and pyruvic acid in kidney homogenates from CKD rats and decreased the expression levels of HIF-1α, PKM2, HK2, α-SMA, vimentin, collagen I and PCNA in kidney tissues. Similar results were observed in vitro. SQ inhibited NRK-49F cell proliferation, glycolysis and the expression levels of HIF-1α, PKM2 induced by TGF-β1. Furthermore, we established NRK-49F cells transfected with siRNA or pDNA to silence or overexpress the HIF-1α gene. Overexpression of HIF-1α promoted cellular secretion of lactic acid and pyruvic acid in TGF-β1-induced NRK-49F cells, however, this change was reversed by intervention with SQ or silencing the HIF-1α gene. Overexpression of HIF-1α can further induce increased PKM2 expression, while SQ intervention can reduce PKM2 expression. Moreover, PKM2 expression was also inhibited after silencing HIF-1α gene, and SQ was not effective even when given.

CONCLUSION

The mechanism of action of SQ was explored from the perspective of energy metabolism, and it was found to regulate PKM2-activated glycolysis, inhibit fibroblast activation, and further ameliorate renal fibrosis in CKD by targeting HIF-1α.

Astragaloside IV relieves passive heymann nephritis and podocyte injury by suppressing the TRAF6/NF-κb axis

The pathogenesis of membranous nephropathy (MN) involves podocyte injury that is attributed to inflammatory responses induced by local immune deposits. Astragaloside IV (AS-IV) is known for its robust anti-inflammatory properties. Here, we investigated the effects of AS-IV on passive Heymann nephritis (PHN) rats and TNF-α-induced podocytes to determine the underlying molecular mechanisms of MN. Serum biochemical parameters, 24-h urine protein excretion and renal histopathology were evaluated in PHN and control rats. The expression of tumor necrosis factor receptor associated factor 6 (TRAF6), the phosphorylation of nuclear factor kappa B (p-NF-κB), the expression of associated proinflammatory cytokines (TNF-α, IL-6 and IL-1β) and the ubiquitination of TRAF6 were measured in PHN rats and TNF-α-induced podocytes. We detected a marked increase in mRNA expression of TNF-α, IL-6 and IL-1β and in the protein abundance of p-NF-κB and TRAF6 within the renal tissues of PHN rats and TNF-α-induced podocytes. Conversely, there was a reduction in the K48-linked ubiquitination of TRAF6. Additionally, AS-IV was effective in ameliorating serum creatinine, proteinuria, and renal histopathology in PHN rats. This effect was concomitant with the suppression of NF-κB pathway activation and decreased expression of TNF-α, IL-6, IL-1β and TRAF6. AS-IV decreased TRAF6 levels by promoting K48-linked ubiquitin conjugation to TRAF6, which triggered ubiquitin-mediated degradation. In summary, AS-IV averted renal impairment in PHN rats and TNF-α-induced podocytes, likely by modulating the inflammatory response through the TRAF6/NF-κB axis. Targeting TRAF6 holds therapeutic promise for managing MN.

Diosgenin protects against cationic bovine serum albumin-induced membranous glomerulonephritis by attenuating oxidative stress and renal inflammation via the NF-κB pathway

CONTEXT

Membranous glomerulonephritis (MGN) is a leading cause of nephrotic syndrome in adults. Diosgenin (DG) has been reported to exert antioxidative and anti-inflammatory effects.

OBJECTIVE

To investigate the renoprotective activity of DG in a cationic bovine serum albumin-induced rat model of MGN.

MATERIALS AND METHODS

Fourty male Sprague-Dawley rats were randomized into four groups. The MGN model was established and treated with a DG dose (10 mg/kg) and a positive control (TPCA1, 10 mg/kg), while normal control and MGN groups received distilled water by gavage for four consecutive weeks. At the end of the experiment, 24 h urinary protein, biochemical indices, oxidation and antioxidant levels, inflammatory parameters, histopathological examination, immunohistochemistry and immunoblotting were evaluated.

RESULTS

DG significantly ameliorated kidney dysfunction by decreasing urinary protein (0.56-fold), serum creatinine (SCr) (0.78-fold), BUN (0.71-fold), TC (0.66-fold) and TG (0.73-fold) levels, and increasing ALB (1.44-fold). DG also reduced MDA (0.82-fold) and NO (0.83-fold) levels while increasing the activity of SOD (1.56-fold), CAT (1.25-fold), glutathione peroxidase (GPx) (1.55-fold) and GSH (1.81-fold). Furthermore, DG reduced Keap1 (0.76-fold) expression, Nrf2 nuclear translocation (0.79-fold), and induced NQO1 (1.25-fold) and HO-1 (1.46-fold) expression. Additionally, DG decreased IL-2 (0.55-fold), TNF-α (0.80-fold) and IL-6 (0.75-fold) levels, and reduced protein expression of NF-κB p65 (0.80-fold), IKKβ (0.93-fold), p-IKKβ (0.89-fold), ICAM-1 (0.88-fold), VCAM-1 (0.91-fold), MCP-1 (0.88-fold) and E-selectin (0.87-fold), and also inhibited the nuclear translocation of NF-κB p65 (0.64-fold).

DISCUSSION AND CONCLUSIONS

The results suggest a potential therapeutic benefit of DG against MGN due to the inhibition of the NF-κB pathway, supporting the need for further clinical trials.

Exploring the therapeutic mechanism of Yuebi decoction on nephrotic syndrome based on network pharmacology and experimental study

OBJECTIVE

This study aimed to explore the material basis of YBD and its possible mechanisms against NS through network pharmacology, molecular docking, and in vivo experiment.

METHODS

Active ingredients and potential targets of YBD were obtained through TCMSP and SwissTargetPrediction. NS-related targets were obtained from GeneCards, PharmGKB, and OMIM databases. The herb-ingredient-target network and PPI network were constructed by Cytoscape 3.9.1 and STRING database. GO and KEGG analyses were performed by DAVID database and ClueGO plugin. The connection between main active ingredients and core targets were revealed by molecular docking. To ascertain the effects and molecular mechanisms of YBD, a rat model was established by PAN.

RESULTS

We collected 124 active ingredients, 269 drug targets, and 2089 disease targets. 119 overlapping were screened for subsequent analysis. PPI showed that AKT1, STAT3, TRPC6, CASP3, JUN, PPP3CA, IL6, PTGS2, VEGFA, and NFATC3 were potential therapeutic targets of YBD against NS. Through GO and KEGG analyses, it showed the therapeutic effect of YBD on NS was closely involved in the regulation of pathways related to podocyte injury, including AGE-RAGE signaling pathway in diabetic complications and MAPK signaling pathway. Five key bioactive ingredients of YBD had the good affinity with the core targets. the experiment confirmed the renoprotective effects of YBD through reducing podocyte injury. Furthermore, YBD could downregulate expressions of PPP3CA, STAT3, NFATC3, TRPC6, and AKT1 in rats.

CONCLUSIONS

YBD might be a potential drug in the treatment of NS, and the underlying mechanism is closely associated with the inhibition of podocyte injury.

Oxidative stress and inflammation are mediated via aryl hydrocarbon receptor signalling in idiopathic membranous nephropathy

Membranous nephropathy (MN) patients are diagnosed by the presence of phospholipase A2 receptor (PLA2R) before they progress to renal failure. However, the subepithelium-like immunocomplex deposit-mediated downstream molecular pathways are poorly understood. The aryl hydrocarbon receptor (AHR), NF-ƙB and Nrf2 pathways play central roles in the pathogenesis and progression of chronic kidney disease. However, their mutual effects on MN require further examination. Thus, we investigated the effect of AHR signalling on the NF-ƙB and Nrf2 pathways in IMN patients, cationic bovine serum albumin (CBSA)-injected rats and zymosan activation serum (ZAS)-treated podocytes. IMN patients show significantly decreased serum total protein and albumin levels, increased urine protein levels and intrarenal IgG4 and PLA2R protein expression in glomeruli compared with controls. IMN patients exhibited increased mRNA expression of intrarenal AHR and its target genes, including CYP1A1, CYP1A2, CYP1B1 and COX-2. This increase was accompanied by significantly upregulated protein expression of CD3, NF-ƙB p65 and COX-2 and significantly downregulated Nrf2 and HO-1 expression. Similarly, CBSA-induced rats showed severe proteinuria and activated intrarenal AHR signalling. This was accompanied by significantly upregulated protein expression of intrarenal p-IκBα, NF-κB p65 and its gene products, including COX-2, MCP-1, iNOS, 12-LOX, p47phox and p67phox, and significantly downregulated protein expression of Nrf2 and its gene products, including HO-1, catalase, GCLC, GCLM, MnSOD and NQO1. These results were further verified in ZAS-induced podocytes. Treatment with the AHR antagonist CH223191 and AHRsiRNA significantly preserved podocyte-specific protein expression and improved the NF-ƙB and Nrf2 pathways in ZAS-induced podocytes. In contrast, similar results were obtained in ZAS-induced podocytes treated with the NF-ƙB inhibitor BAY 11-7082 and NF-κBp65 siRNA. However, neither method had a significant effect on AHR signalling. Collectively, these results indicate that the NF-ƙB pathway is a downstream target of AHR signalling. Our findings suggest that blocking AHR signalling inhibits oxidative stress and inflammation, thereby improving proteinuria and renal injury.

Roles of interferon regulatory factor 4 in the AKI-CKD transition, glomerular diseases and kidney allograft rejection

Interferon regulatory factor 4 (IRF4) is expressed in immune cells and is a member of the interferon regulatory factor family. Recently, it has been found that IRF4 plays important roles in the acute kidney injury (AKI)-chronic kidney disease (CKD) transition, glomerular diseases and kidney allograft rejection. In particular, the relationship between IRF4 and the AKI-CKD transition has attracted widespread attention. Furthermore, it was also found that the deficiency of IRF4 hindered the transition from AKI to CKD through the suppression of macrophage-to-fibroblast conversion, inhibition of M1-M2 macrophage polarization, and reduction in neutrophil inward flow. Additionally, an examination of the crucial role of IRF4 in glomerular disease was conducted. It was reported that inhibiting IRF4 could alleviate the progression of glomerular disease, and potential physiopathology mechanisms associated with IRF4 were postulated. Lastly, IRF4 was found to have detrimental effects on the development of antibody-mediated rejection (ABMR) and T-cell-mediated rejection (TCMR).

PLA2G12B Mediates Arachidonic Acid Metabolism through Activation of the NF-κB Pathway to Promote Membrane Nephropathy

INTRODUCTION

The disruption of podocyte structure and function are the main pathological mechanism of membranous nephropathy (MN). Phospholipases A2, Group XII B (PLA2G12B) was reported involved in the regulation of MN by interfering with arachidonic acid (AA) metabolism, but there is a lack of sufficient evidence. In this study, we investigated the role and molecular mechanism of PLA2G12B in MN.

METHODS

C57BL/6 mice were used to establish MN model to extract primary podocytes, then divided into control, model, si-phospholipases A2 receptor (PLA2R), PLA2G12B, PLA2G12B + si-PLA2R, PLA2G12B + nuclear factor kappa-B (NF-κB) inhibitor, PLA2G12B + NF-κB inhibitor + si-PLA2R groups. Hematoxylin-eosin staining and immunofluorescence were used to detect kidney histological arrangement, serum levels of cholesterol-related indices, and AA. Genes and proteins associated with metabolism and inflammatory factors were detected by quantitative real-time PCR and Western blot.

RESULTS

The results revealed that AA metabolites were activated in the MN model mice, and the expression of PLA2G12B and NF-κB pathway levels were elevated. Besides, cellular experiments demonstrated that prostaglandin I2 (PGI2), thromboxane A2 (TXA2), leukotriene B4 (LTB4), and NF-κB pathway were significantly increased in the PLA2G12B group. Also, PLA2G12B promotes apoptosis and suppresses cell activity in podocytes, and these effects could be antagonized by NF-κB inhibitors. Furthermore, with the inference of si-PLA2R, the NF-κB inhibitors' effects were reversed.

CONCLUSION

Promotional effects of PLA2G12B in primary MN are associated with the regulation of AA metabolism and NF-κB pathway.

Metformin combined with rapamycin ameliorates podocyte injury in idiopathic membranous nephropathy through the AMPK/mTOR signaling pathway

Autophagy activation protects against podocyte injury in idiopathic membranous nephropathy (IMN). The AMPK/mTOR signaling pathway is a vital autophagy regulatory pathway. Metformin promotes autophagy, whereas rapamycin is an autophagy agonist. However, the therapeutic mechanisms of metformin and rapamycin in IMN remain unclear. Thus, we examined the mechanisms of action of metformin and rapamycin in IMN by regulating the AMPK/mTOR autophagy signaling pathway. Female Sprague-Dawley (SD) rats were treated with cationic bovine serum albumin (C-BSA) to establish an IMN model and were randomly divided into IMN model, metformin, rapamycin, and metformin + rapamycin groups. A control group was also established. Metformin and rapamycin were used as treatments. Renal histological changes, urinary protein excretion, the protein expression levels of key AMPK/mTOR signaling pathway proteins, renal tissue cell apoptosis, and autophagy-associated proteins (Beclin 1 and LC3) were examined. In addition, a C5b-9 sublysis model using the MPC-5 mouse podocyte cell line was established to verify the effect of metformin combined with rapamycin on podocytes. Metformin combined with rapamycin improved urinary protein excretion in IMN rats. Metformin combined with rapamycin attenuated the inflammatory response, renal fibrosis, and podocyte foot process fusion. In addition, it improved autophagy in podocytes as demonstrated by the enhanced expression of Beclin-1, p-AMPK/AMPK, LC3-II/I, and autophagosomes in podocytes and decreased p-mTOR/mTOR expression. In conclusion, metformin combined with rapamycin decreased proteinuria, improved renal fibrosis and podocyte autophagy via AMPK/mTOR pathway in IMN rats. The metformin and rapamycin decreased proteinuria and inproved renal fibrosis in IMN model rats.

Moshen granule ameliorates membranous nephropathy by regulating NF-ƙB/Nrf2 pathways via aryl hydrocarbon receptor signalling

Considerable achievements were realized in illuminating underlying pathological mechanisms of patients with idiopathic membranous nephropathy (IMN). Although IMN patients are well diagnosed before they reach renal failure, no currently available drug intervention is effective in halting IMN progression. In this study, we assess Moshen granule (MSG) effect on IMN patients and cationic bovine serum albumin (CBSA)-induced rats. Increasing studies has indicated that activation of aryl hydrocarbon receptor (AHR) was related to oxidative stress and inflammation. We further determine MSG effect on AHR, nuclear factor ƙB (NF-ƙB) and nuclear factor erythroid 2-related factor 2 (Nrf2) in the CBSA-induced rats. MSG markedly reduces proteinuria and improves kidney function in both IMN patients and rats induced by CBSA. MSG markedly inhibits increased mRNA expressions of intrarenal AHR and its four downstream target genes including CYP1A1, CYP1A2, CYP1B1 and COX-2 compared with untreated CBSA-induced rats. This is accompanied by markedly downregulated protein expressions of p-IƙBα and NF-ƙB p65 and its downstream gene products including MCP-1, COX-2, 12-LOX, iNOS, p47phox and p67phox, while markedly preserves protein expressions of Nrf2 and its downstream gene products including catalase, HO-1, GCLM, GCLC, MnSOD and NQO1 in the kidney tissues. These data suggests MSG blunts podocyte damage through inhibiting activation of NF-ƙB/Nrf2 pathway via AHR signaling. This finding may provide a promising therapy for treatment of IMN through oxidative stress and inflammation.

Sanqi Qushi Granule Alleviates Proteinuria and Podocyte Damage in NS Rat: A Network Pharmacology Study and in vivo Experimental Validation

Background

Nephrotic syndrome (NS) and its numerous complications remain the leading causes of morbidity and mortality globally. Sanqi Qushi granule (SQG) is clinically effective in NS. However, its potential mechanisms have yet to be elucidated.

Methods

A network pharmacology approach was employed in this study. Based on oral bioavailability and drug-likeness, potential active ingredients were picked out. After acquiring overlapping targets for drug genes and disease-related genes, a component-target-disease network and protein-protein interaction analysis (PPI) were constructed using Cytoscape, followed by GO and KEGG enrichment analyses. Adriamycin was injected into adult male Sprague-Dawley (SD) rats via the tail vein to establish NS model. Kidney histology, 24-hr urinary protein level, creatinine (Cr), blood urea nitrogen (BUN), triglyceride (TG), total cholesterol (TC), and low-density lipoprotein (LDL-C) level were assessed. Western blotting, immunohistochemistry, and TUNEL staining were applied.

Results

In total, 144 latent targets in SQG acting on NS were screened by a network pharmacology study, containing AKT, Bax, and Bcl-2. KEGG enrichment analysis suggested that PI3K/AKT pathway was enriched primarily. In vivo validation results revealed that SQG intervention ameliorated urine protein level and podocyte lesions in the NS model. Moreover, SQG therapy significantly inhibited renal cells apoptosis and decreased the ratio of Bax/Bcl-2 protein expression. Moreover, we found that Caspase-3 regulated the PI3K/AKT pathway in NS rats, which mediated the anti-apoptosis effect.

Conclusion

By combining network pharmacology with experimental verification in vivo, this work confirmed the treatment efficacy of SQG for NS. SQG protected podocyte from injury and inhibited kidney apoptosis in NS rats via the PI3K/AKT pathway at least partially.

The efficacy and safety of Sanqi Qushi Granule in patients with idiopathic membranous nephropathy --protocol of a multicenter, randomized control trial (SQ-AUTUMN)

BACKGROUND

Adult nephropathy is mainly caused by idiopathic membranous nephropathy (IMN). In cases of proteinuria, Modified Ponticelli Regimens (MPR) are often successful. However, it can cause adverse side effects. Oral Sanqi Qushi Granule (SQG) with MPR is effective in patients with IMN. However, whether it can improve the remission rate of IMN and shorten the remission time is unknown. In this trial, SQG with MPR on IMN will be evaluated clinically for its efficacy and safety.

METHODS

We will randomly assign IMN patients who meet the criteria to receives SQG plus cyclical Cyclophosphamide (CTX)/steroids or with placebo plus cyclical CTX/steroids for 6 months. A 12-month follow-up will be conducted on them. Status of remission will be used to assess treatment efficacy.

DISCUSSION

This study aims to appraise whether treatment with SQG plus cyclical CTX/steroids is superior to placebo plus cyclical CTX/steroids in the remission rate of patients with adult IMN. Adverse events of SQG plus MPR will be also evaluated for further researches about Chinese Medicine and MPR on whether it can improve the remission rate of IMN in half a year and shorten the remission time and relieve adverse effects will also be clarified.

TRIAL REGISTRATION

Chinese Clinical Trial Registry ChiCTR2200061953 . Registered on 13 July 2022.

Integrated Network Pharmacology Analysis and Experimental Validation to Investigate the Molecular Mechanism of Triptolide in the Treatment of Membranous Nephropathy

BACKGROUND

Triptolide, a major active ingredient isolated from Tripterygium wilfordii Hook f., is effective in the treatment of membranous nephropathy (MN); however, its pharmacological mechanism of action has not yet been clarified. We applied an approach that integrated network pharmacology and experimental validation to systemically reveal the molecular mechanism of triptolide in the treatment of MN.

METHODS

First, potential targets of triptolide and the MN-related targets were collected from publicly available database. Then, based on a protein-protein interaction network as well as GO and KEGG pathway enrichment analyses, we constructed target-pathway networks to unravel therapeutic targets and pathways. Moreover, molecular docking was applied to validate the interactions between the triptolide and hub targets. Finally, we induced passive Heymann nephritis (PHN) rat models and validated the possible molecular mechanisms of triptolide against MN.

RESULTS

The network pharmacology results showed that 118 intersected targets were identified for triptolide against MN, including mTOR, STAT3, CASP3, EGFR and AKT1. Based on enrichment analysis, signaling pathways such as PI3K/AKT, MAKP, Ras and Rap1 were involved in triptolide treatment of MN. Furthermore, molecular docking confirmed that triptolide could bind with high affinity to the PIK3R1, AKT1 and mTOR, respectively. Then, in vivo experiments indicated that triptolide can reduce 24 h urine protein (P < 0.01) and protect against renal damage in PHN. Serum albumin level was significantly increased and total cholesterol, triglycerides, and low-density lipoprotein levels were decreased by triptolide (P < 0.05). Compared with PHN group, triptolide treatment regulated the PI3K/AKT/mTOR pathway according to Western blot analyses.

CONCLUSION

Triptolide could exert antiproteinuric and renoprotective effects in PHN. The therapeutic mechanism of triptolide may be associated with the regulation of PI3K/AKT/mTOR signaling pathway. This study demonstrates the pharmacological mechanism of triptolide in the treatment of MN and provides scientific evidence for basic and clinical research.

Membranous nephropathy: Systems biology-based novel mechanism and traditional Chinese medicine therapy

Membranous nephropathy (MN) is a renal-limited non-inflammatory autoimmune disease in the glomerulus, which is the second or third main cause of end-stage kidney diseases in patients with primary glomerulonephritis. Substantial achievements have increased our understanding of the aetiology and pathogenesis of murine and human MN. The identification of nephritogenic autoantibodies against neutral endopeptidase, phospholipase A2 receptor (PLA2R) and thrombospondin type-1 domain-containing 7A (THSD7A) antigens provide more specific concept-driven intervention strategies for treatments by specific B cell-targeting monoclonal antibodies to inhibit antibody production and antibody-antigen immune complex deposition. Furthermore, additional antibody specificities for antigens have been discovered, but their pathogenic effects are uncertain. Although anti-PLA2R and anti-THSD7A antibodies as a diagnostic marker is widely used in MN patients, many questions including autoimmune response development, antigenic epitopes, and podocyte damage signalling pathways remain unresolved. This review describes the current available evidence regarding both established and novel molecular mechanisms based on systems biology approaches (gut microbiota, long non-coding RNAs, metabolite biomarkers and DNA methylation) in MN, with an emphasis on clinical findings. This review further summarizes the applications of traditional Chinese medicines such as Tripterygium wilfordii and Astragalus membranaceus for MN treatment. Lastly, this review considers how the identification of novel antibodies/antigens and unresolved questions and future challenges reveal the pathogenesis of MN.

Traditional Chinese Medicine in the Treatment of Chronic Kidney Diseases: Theories, Applications, and Mechanisms

Chronic kidney disease (CKD) is a common and progressive disease that has become a major public health problem on a global scale. Renal fibrosis is a common feature in the pathogenesis of CKD, which is mainly related to the excessive accumulation and deposition of extracellular matrix caused by various inflammatory factors. No ideal treatment has yet been established. In recent years, based on the traditional Chinese medicine (TCM) theory of CKD and its molecular mechanism, clinical evidence or experimental studies have confirmed that a variety of Chinese materia medica (CMM) and their effective components can delay the progress of CKD. TCM believes that the pathogenesis of CKD is the deficiency in the root and excess in the branch, and the deficiency and excess are always accompanied by the disease. The strategies of TCM in treating CKD are mainly based on invigorating Qi, tonifying the kidneys, promoting blood circulation, removing stasis, eliminating heat and dampness, removing turbidity, and eliminating edema, and these effects are multitargeted and multifunctional. This review attempts to summarize the theories and treatment strategies of TCM in the treatment of CKD and presents the efficacy and mechanisms of several CMMs supported by clinical evidence or experimental studies. In addition, the relationship between the macroscopic of TCM and the microscopic of modern medicine and the problems faced in further research were also discussed.

Recent Advances in Clinical Diagnosis and Pharmacotherapy Options of Membranous Nephropathy

Membranous nephropathy (MN) is the most common cause of nephrotic syndrome among adults, which is the leading glomerular disease that recurs after kidney transplantation. Treatment for MN remained controversial and challenging, partly owing to absence of sensitive and specific biomarkers and effective therapy for prediction and diagnosis of disease activity. MN starts with the formation and deposition of circulating immune complexes on the outer area in the glomerular basement membrane, leading to complement activation. The identification of autoantibodies against the phospholipase A₂ receptor (PLA₂R) and thrombospondin type-1 domain-containing protein 7A (THSD7A) antigens illuminated a distinct pathophysiological rationale for MN treatments. Nowadays, detection of serum anti-PLA₂R antibodies and deposited glomerular PLA₂R antigen can be routinely applied to MN. Anti-PLA₂R antibodies exhibited much high specificity and sensitivity. Measurement of PLA₂R in immune complex deposition allows for the diagnosis of PLA₂R-associated MN in patients with renal biopsies. In the review, we critically summarized newer diagnosis biomarkers including PLA₂R and THSD7A tests and novel promising therapies by using traditional Chinese medicines such as Astragalus membranaceus, Tripterygium wilfordii, and Astragaloside IV for the treatment of MN patients. We also described unresolved questions and future challenges to reveal the diagnosis and treatments of MN. These unprecedented breakthroughs were quickly translated to clinical diagnosis and management. Considerable advances of detection methods played a critical role in diagnosis and monitoring of treatment.

The Ameliorative Effect of Mahuang Fuzi and Shenzhuo Decoction on Membranous Nephropathy of Rodent Model is Associated With Autophagy and Wnt/β-Catenin Pathway

The increased incidence of membranous nephropathy (MN) has made it the most common pathological type of primary nephrotic syndrome in adults in China. According to the theory of Traditional Chinese Medicine (TCM), Mahuang Fuzi (Chinese ephedra and Radix Aconiti Lateralis Preparata) and Shenzhuo Decoction (MFSD) could be used to treat such diseases. We treated patients of MN with MFSD, and observed comparable efficacy to glucocorticoid and/or immunosuppressants. In this study, we observed the therapeutic effect of MFSD on the rat model of passive Heymann nephritis (PHN), a classical MN model. Our results showed that MFSD treatment significantly reduced urinary protein level and podocyte injury in PHN rats, and correspondingly improved renal pathology, with the improvement effect on MN comparable to that of Cyclosporine A (CsA) alone. To explore the potential therapeutical mechanism of MFSD, the main chemical components of MFSD were determined by High-performance liquid chromatography-mass spectrometry (HPLC-MS). There were about 30 active components of MFSD. Next, based on network pharmacology methods, we screened related targets of MSFD on MN, which provided a preliminary understanding of the MFSD bioactive compounds. The clustering analysis showed that its active site might be in the autophagy-related protein and Wnt/β-catenin pathway, which was related to podocyte injury. Finally, we observed an improvement in renal autophagy and a down-regulation of the Wnt/β-catenin pathway after MSFD treatment in a PHN rat model. According to this study, autophagy and Wnt/β-catenin pathway may be potential targets for MFSD in the treatment of MN.

Acidic Stigma maydis polysaccharides protect against podocyte injury in membranous nephropathy by maintenance of glomerular filtration barrier integrity and gut-kidney axis

MN mice models were induced by C-BSA, and we found that acidic stigma maydis polysaccharides  maintained the integrity of the glomerular filtration barrier by promoting slit diaphragm proteins expression and PI3K/AKT signaling.

Sanqi Oral Solution Mitigates Proteinuria in Rat Passive Heymann Nephritis and Blocks Podocyte Apoptosis via Nrf2/HO-1 Pathway

Idiopathic membranous nephropathy (IMN) is the most common pathological type in adult nephrotic syndrome where podocyte apoptosis was found to mediate the development of proteinuria. Sanqi oral solution (SQ), an effective Chinese herbal preparation clinically used in treatment of IMN for decades, plays an important role in reducing proteinuria, but the underlying mechanisms have not been fully elucidated yet. The current study tested the hypothesis that SQ directly lessens proteinuria in IMN by reducing podocyte apoptosis. To investigate the effects of SQ, we established the experimental passive Heymann nephritis (PHN) rat model induced by anti-Fx1A antiserum in vivo and doxorubicin hydrochloride (ADR)-injured apoptotic podocyte model in vitro. SQ intervention dramatically reduced the level of proteinuria, together with the rat anti-rabbit IgG antibodies, complement C3, and C5b-9 deposition in glomerulus of PHN rats, accompanied by an elevation of serum albumin. Protein expression of synaptopodin, marker of podocyte injury, restored after SQ administration, whereas the electron microscopic analysis indicated that fusion of foot processes, and the pachynsis of glomerular basement membrane was markedly diminished. Further studies showed that SQ treatment could significantly inhibit podocyte apoptosis in PHN rats and ADR-injured podocytes, and protein levels of Cleaved Caspase-3 or the ratio of Bax/Bcl-2 were significantly decreased with SQ treatment in vivo or in vitro. Moreover, we found that the nuclear factor erythroid 2–related factor-2/heme oxygenase 1 (Nrf2/HO-1) pathway mediated the anti-apoptosis effective of SQ in podocyte. Thus, SQ mitigates podocyte apoptosis and proteinuria in PHN rats via the Nrf2/HO-1 pathway.

Structural modulation of gut microbiota during alleviation of experimental passive Heymann nephritis in rats by a traditional Chinese herbal formula

BACKGROUND

Jianpi-Qushi-Heluo formula (JQHF) has been used to treat idiopathic membranous nephropathy (IMN) in hospitals for many years.

PURPOSE

Elucidating the protective effect and exploring the potential mechanism of JQHF against IMN.

METHODS

Passive Heymann nephritis (PHN) was induced in rats by a single tail vein injection of anti-Fx1A antiserum. Then, the animals were treated with JQHF at 16.2 g/kg or 32.4 g/kg, with benzepril (10 mg/kg) as a positive control. Renal function was evaluated by biochemical measurements and pathological testing. Fecal samples were collected before and after treatment to analyze the gut microbiota composition by shotgun whole metagenome sequencing.

RESULTS

JQHF exhibited potent efficacy in ameliorating PHN at both doses, as revealed by decreasing the deposition of IgG and C5b-9, relieving podocyte injury, and reducing glomerular and tubular cell apoptosis. The lower dose was corresponding to the clinical dosage and showed better therapeutic effects than the higher dose. Metagenomic analysis showed that gavage with 16.2 g/kg of JQHF shifted the structure of the gut microbiota in PHN rats and significantly increased the relative abundances of Prevotella copri, Lactobacillus vaginalis and Subdoligranulum variabile. Particularly, S. variabile was strongly negatively correlated with serum levels of TC and TG, the deposition of IgG and C5b-9, and apoptosis of glomerular cells.

CONCLUSIONS

The JQHF is an effective agent for the treatment of experimental PHN. The PHN-allevating effect of JQHF is associated with specific alternation of gut microbiota.

Ameliorated membranous nephropathy activities of two ethanol extracts from corn silk and identification of flavonoid active compounds by LC-MS2

The current study looks to evaluate the effect of corn silk flavonoids on membranous nephropathy (MN). Polyamide resin (PR) can be used to enrich corn silk ethanol extract (CSEE) to obtain flavonoid-rich extract (PR-CSEE), the total flavonoid content (TFC) of which we found to be 57.4%. The results of scanning electron microscope, Fourier-transform infrared, and high-performance liquid chromatography analyses determined that PR-CSEE and CSEE have different structural characteristics, but that PR-CSEE has higher TFC. MN mice models were induced by cationic bovine serum albumin, and we found that PR-CSEE administration reduced urine protein levels markedly, while renal function, glomerular atrophy, inflammatory infiltration, and in-serum immunoglobulin G and complement 3 content were improved. Through LC-MS² spectrometry analysis, we pinpointed the 12 major flavonoid active compounds in PR-CSEE. These findings suggest that PR-CSEE can act as a potential functional food material by which to improve MN.

Tetrandrine may treat membranous glomerulopathy via P13K/Akt signaling pathway regulation: therapeutic mechanism validation using Heymann nephritis rat model

Membranous glomerulopathy (MGN) is an autoimmune kidney disease that is the primary cause of nephrotic syndrome (NS) in adults. Tetrandrine, a bisbenzylisoquinoline alkaloid, is known to have numerous pharmacological effects. In this study, network pharmacology analysis and experimental validation were conducted to analyze the mechanisms by which tetrandrine functions as a therapeutic intervention for MGN. A systematic network pharmacology method was applied to identify potential targets and determine the therapeutic mechanism of tetrandrine in MGN treatment. A Heymann nephritis (HN) rat model was developed to assess the therapeutic effects of tetrandrine on NS and validate the predicted molecular mechanisms. We obtained 86 potential targets of tetrandrine for the treatment of NS. In vivo experiments showed that tetrandrine could reduce the 24-h urine protein content, decrease glomerular basement membrane proliferation, and significantly decrease thylakoid stroma and cell proliferation in the HN rat kidney tissue. Moreover, tetrandrine suppressed kidney cell apoptosis and upregulated the expression of nephrin and podocin in HN model rats. qRT-PCR results revealed that tetrandrine inhibited IL-1β, TNFα, and MCP-1 levels in HN model rats. Western blot results indicated that tetrandrine can protect against MGN via the PI3K/Akt signaling pathway. Thus, by using a combination of network and experimental pharmacology methods, we demonstrate that tetrandrine can treat MGN via the PI3K/Akt signaling pathway and provide novel insights into the mechanisms underlying tetrandrine-mediated management of MGN.

Circ_0000524/miR-500a-5p/CXCL16 axis promotes podocyte apoptosis in membranous nephropathy

BACKGROUND

Podocytes apoptosis is a hallmark of membranous nephropathy (MN). Circ_0000524 has been reported to be associated with patients with MN, whereas the effect of circ_0000524 on podocytes apoptosis and the underlying mechanisms in MN have not been elaborated.

METHODS

Quantitative real-time polymerase chain reaction (qRT-PCR) and Western blot were performed to detect the expressions of circ_0000524, microRNA-500a-5p (miR-500a-5p), and C-X-C chemokine ligand 16 (CXCL16) in MN tissues and podocytes. Podocyte injury was induced by angiotensin II (AngII). Cell apoptosis was detected by flow cytometry. Caspase-3 or caspase-9 activity was evaluated using a caspase-3 or caspase-9 activity assay kit, respectively. Dual-luciferase reporter assay, RNA immunoprecipitation (RIP) and pull-down assay were used to address the relationship among circ_0000524,miR-500a-5p and CXCL16.

RESULTS

Upregulation of circ_0000524 and CXCL16 and low expression of miR-500a-5p were observed in MN tissues. AngII treatment induced the overexpression of circ_0000524 and CXCL16, a decrease of miR-500a-5p, and induced cell apoptosis in podocytes. Circ_0000524 negatively modulated the expression of miR-500a-5p. Circ_0000524 depletion inhibited podocyte apoptosis, which was rescued by loss of miR-500a-5p. miR-500a-5p contained the binding sites with CXCL16. Circ_0000524 knockdown hampered CXCL16 expression by upregulating miR-500a-5p expression. Additionally, miR-500a-5p upregulation suppressed AngII-induced podocyte apoptosis, which was rescued by enhanced expression of CXCL16.

CONCLUSION

Circ_0000524/miR-500a-5p/CXCL16 pathway regulated podocyte apoptosis in MN.

Curcumin Improves the Renal Autophagy in Rat Experimental Membranous Nephropathy via Regulating the PI3K/AKT/mTOR and Nrf2/HO-1 Signaling Pathways

Membranous nephropathy (MN, also known as membranous glomerulopathy) is one of the many glomerular diseases causing nephrotic syndrome. The literature indicates that autophagy is associated with the homeostasis of podocytes in glomeruli. Curcumin, the main active component in turmeric, has drawn attention for its effective bioactivities against chronic kidney disease. The current study was aimed at assessing the effects of curcumin and exploring the underlying mechanism that mediates autophagy in an animal model of passive Heymann nephritis (PHN) in rats. Passive Heymann nephritis (PHN) was induced in male SD rats by intraperitoneal injection of anti-Fx1A serum. The rats were divided into 3 groups: control (n = 10, normal diet), model group (n = 10, 0.5% sodium carboxymethylcellulose), and curcumin (n = 10, 300 mg/kg/d). The kidney function and oxidative stress indicators were measured using commercial diagnostic kits, and the histomorphology of renal tissues was observed. The number of podocytes was measured by immunohistochemistry. Meanwhile, the autophagosomes in podocyte were analyzed by transmission electron microscopy and the immunofluorescence assay pointing to p62, an autophagic marker. Western blot analyzed the levels of apoptosis, autophagy, PI3K/AKT/mTOR, and Nrf2/HO-1 pathway-associated proteins. The total cholesterol (TC), triglycerides (TG), creatinine (Scr), blood urea nitrogen (BUN), urine volume, and urine albumin of PHN rats were significantly reduced by the administration of curcumin and attenuated renal histomorphological changes in model rats. Meanwhile, curcumin improved the oxidative stress response by decreasing MDA and increasing SOD, GSH, and CAT levels in the kidney of PHN rats. Furthermore, curcumin significantly ameliorated the podocyte loss, along with the fusion, and increased the autophagic vacuoles compared to the PHN control rats. In addition, curcumin downregulated the expression of Bax, Caspase-3, p62, PI3K, p-AKT, and p-mTOR proteins and upregulated the Bcl-2, beclin1, LC3, Nrf2, and HO-1 levels in this animal model. The results provide a scientific basis that curcumin could significantly alleviate the development of MN by inducing autophagy and alleviating renal oxidative stress through the PI3K/AKT/mTOR and Nrf2/HO-1 pathways.

Sanqi Oral Solution Ameliorates Renal Ischemia/Reperfusion Injury via Reducing Apoptosis and Enhancing Autophagy: Involvement of ERK/mTOR Pathways

Ischemia-reperfusion (I/R) induced acute kidney injury (AKI) is a significant health problem with high morbidity and mortality, yet prophylaxis strategies and effective drugs are limited. Sanqi oral solution (SQ) is a formulated medicine widely used in clinical settings to treat various renal diseases via enriching qi and activating blood circulation while its role on I/R-AKI remains unclear. Herein, by establishing rat I/R-AKI models, we intended to investigate the effect of SQ on the prevention of I/R-AKI and explore its underlying mechanisms. We demonstrated that SQ treatment significantly attenuated renal dysfunction of I/R-AKI, alleviated histological damages, inhibited renal apoptosis, and enhanced autophagy. Further investigation proved that SQ could significantly inhibit the activation of ERK and mTOR signaling pathways. Moreover, its renoprotective effect can be abolished by autophagy inhibitor 3-methyladenine (3-MA). Collectively, our results suggest that SQ exerts renoprotective effects on renal I/R injury via reducing apoptosis and enhancing autophagy, which are associated with regulating ERK/mTOR pathways.

How Does Herbal Medicine Treat Idiopathic Membranous Nephropathy?

Idiopathic membranous nephropathy (IMN) has made increasing progress in mechanism and treatment research. Herbal medicine is gradually being accepted as an alternative therapy in treating IMN. However, the intervention mechanism of herbal medicine in the treatment of membranous nephropathy is still unclear. In this review, we summarize some achievements of herb medicine in treating IMN and discuss the research direction of herb in IMN. Finally, we propose the dilemma about the study on the treatment of IMN with herb medicine. We hope that this article can bring some thoughts for clinical and scientific researchers on the treatment of IMN with herb medicine.

Astragalus mongholicus Bunge and Panax notoginseng (Burkill) F.H. Chen Formula for Renal Injury in Diabetic Nephropathy-In Vivo and In Vitro Evidence for Autophagy Regulation

Background

Diabetic nephropathy (DN) is a serious complication of diabetes mellitus (DM) with limited treatment options. DN leads to progressive renal failure and accelerates rapidly into end-stage renal disease. Astragalus mongholicus Bunge and Panax notoginseng (Burkill) F.H. Chen formula (APF) is a traditional Chinese medicine (TCM) formula widely used to treat chronic kidney diseases (CKD) in the clinic in the southwest of China. The aim of this study is to explore how APF and its related TCM theory work on DN and whether mTOR/PINK1/Parkin signaling plays a part in this process.

Methods

HPLC was used for preliminary chemical analysis and quantitative analysis of the five components of APF. An in vivo autophagy deficiency model was established in C57BL/6 mice by streptozocin (STZ) combined with a high-fat and high-sugar diet, while the in vitro autophagy deficiency model was induced with high glucose (HG) in renal mesangial cells (RMCs). Renal histopathology staining was performed to investigate the extents of inflammation and injury. Real time-PCR and Western blotting techniques were utilized to assess autophagy-related proteins.

Results

APF significantly ameliorated renal injury in DN mice, specifically restoring blood urea nitrogen, serum creatinine, and 24-hour albuminuria. APF also reduced the mRNA and protein expressions of TNFα, IL-1β, and IL-6 in STZ-induced DN mice. Furthermore, APF improved the autophagy deficiency induced by STZ in vivo or HG in vitro, as revealed by changes in the expressions of mTOR, PINK1, Parkin, Beclin 1, p62, and LC3B. Notably, inhibition of autophagy with 3-methyladenine in APF-treated RMCs aggravated cellular damage and altered mTOR/PINK1/Parkin signaling, indicating that APF rescued HG damage through promoting autophagy.

Conclusion

APF may protect the kidneys from inflammation injuries in DN by upregulating autophagy via suppressing mTOR and activating PINK1/Parkin signaling. This experimental evidence strongly supports APF as a potential option for the prevention and treatment of DN.

Research Progress in the Treatment of Idiopathic Membranous Nephropathy using Traditional Chinese Medicine

This article reviews the most significant literature of the recent years on the treatment of idiopathic membranous nephropathy (IMN) with traditional Chinese medicine (TCM). One major goal of the article is to classify and summarize the research on the clinical aspects and the associated mechanisms of the use of Chinese herbal compounds and single drugs to treat IMN. It was found that TCM treats IMN via two major approaches: by benefiting qi, activating blood circulation and eliminating dampness, or by benefiting qi and nourishing yin. The method of benefiting qi, to activate blood circulation and eliminate dampness for dredging channels, is the most popular. The commonly used drugs in this approach include Huang Qi (astragalus), Dang Shen (codonopsis root), Bai Zhu (white atractylodes rhizome), Fu Ling (poria cocos), Dang Gui (angelica sinensis), and so on. Several randomized, controlled, clinical trials are reviewed in the article, including a multicenter one.

Co-delivery of p38α MAPK and p65 siRNA by novel liposomal glomerulus-targeting nano carriers for effective immunoglobulin a nephropathy treatment

Glomerulonephritis related renal failure is a frequent cause of end-stage renal disease, and immunoglobulin A nephropathy (IgAN) is the most frequent type of primary glomerulonephritis. As damage induced by IgAN mostly attributes to inflammation responses, inhibiting inflammation in glomerulus can protect normal renal function and delay the onset of renal failure. Hence, reducing levels of p38 MAPK and p65 which are essential regulators in p38 MAPK and NF-κB related inflammation responses could be effective against IgAN. Here, we rationally designed and constructed size- and surface charge- dependent glomerulus-targeting liposomal nanoparticles which are loaded with both p38α MAPK and p65 siRNA. Experiments show that our nanoparticles successfully crossed fenestrated endothelium, accumulated in mesangial cells and endothelial cells, efficiently silenced p38α MAPK and p65 genes, and eventually alleviated proteinuria, inflammation and excessive extracellular matrix deposition in mouse IgAN models. This siRNA co-delivery system thus represents a promising treatment option for IgAN and offers a versatile platform for other glomerular problems. Our work also highlights a novel strategy of glomerulus-targeting and an encouraging therapeutic route for other inflammatory diseases.