Triptolide reduces proteinuria in experimental membranous nephropathy and protects against C5b-9-induced podocyte injury in vitro

The effects of Tripterygium wilfordii Hook F on renal outcomes in type 2 diabetic kidney disease patients with severe proteinuria: a single-center cohort study

AIM

Tripterygium wilfordii Hook F (TwHF) has been shown to substantially reduce proteinuria in patients with diabetic kidney disease (DKD); however, the effect of TwHF on renal outcomes in DKD remains unknown. Accordingly, we aimed to establish the effects of TwHF on renal outcomes in patients with DKD.

METHODS

Overall, 124 patients with DKD, induced by type 2 diabetes mellitus, with 24-h proteinuria > 2 g, and an estimated glomerular filtration rate > 30 mL/min/1.73 m2 were retrospectively investigated. The renal outcomes were defined as doubling serum creatinine levels or end-stage kidney disease. Kaplan-Meier curves and Cox regression analyses were performed to analyze prognostic factors for renal outcomes.

RESULTS

By the end of the follow-up, renal outcomes were observed in 23 and 11 patients in the non-TwHF and TwHF groups, respectively (p = 0.006). TwHF significantly reduced the risk of renal outcomes (adjusted hazard ratio [HR] 0.271, 95% confidence interval [CI] 0.111-0.660, p = 0.004) in patients with chronic kidney disease (CKD) G3 (adjusted HR 0.274, 95%CI 0.081-0.932, p = 0.039). Based on the Kaplan-Meier analysis, 1- and 3-year proportions of patients without renal outcomes were significantly lower in the non-TwHF group than those in the TwHF group (92.8% vs. 95.5% and 47.2% vs. 76.8%, respectively; p = 0.0018).

CONCLUSION

In DKD patients with severe proteinuria, TwHF could prevent DKD progression, especially in patients with CKD G3. A randomized clinical trial is needed to elucidate the benefits of TwHF on renal outcomes in patients with DKD.

Glomerulus-Targeted ROS-Responsive Polymeric Nanoparticles for Effective Membranous Nephropathy Therapy

Membranous nephropathy (MN) is a common immune-mediated glomerular disease that requires the development of safe and highly effective therapies. Celastrol (CLT) has shown promise as a therapeutic molecule candidate, but its clinical use is currently limited due to off-target toxicity. Given that excess levels of reactive oxygen species (ROS) contributing to podocyte damage is a key driver of MN progression to end-stage renal disease, we rationally designed ROS-responsive cationic polymeric nanoparticles (PPS-CPNs) with a well-defined particle size and surface charge by employing poly(propylene sulfide)-polyethylene glycol (PPS-PEG) and poly(propylene sulfide)-polyethylenimine (PPS-PEI) to selectively deliver CLT to the damaged glomerulus for MN therapy. Experimental results show that PPS-CPNs successfully crossed the fenestrated endothelium, accumulated in the glomerular basement membrane (GBM), and were internalized by podocytes where rapid drug release was triggered by the overproduction of ROS, thereby outperforming nonresponsive CLT nanotherapy to alleviate subepithelial immune deposits, podocyte foot process effacement, and GBM expansion in a rat MN model. Moreover, the ROS-responsive CLT nanotherapy was associated with significantly lower toxicity to major organs than free CLT. These results suggest that encapsulating CLT into PPS-CPNs can improve efficacy and reduce toxicity as a promising treatment option for MN.

Podocyte Pathogenic Bone Morphogenetic Protein-2 Pathway and Immune Cell Behaviors in Primary Membranous Nephropathy

Primary membranous nephropathy (PMN) is one of the leading causes of end-stage renal disease, and the most frequent cause of massive proteinuria in nondiabetic adults, resulting in fatal complications. However, the underlying pathomechanisms of PMN remain largely unclear. Here, single-cell RNA sequencing is employed to analyze kidney biopsies from eleven PMN patients and seven healthy subjects. Profiling 44 060 cells from patients allowed us to characterize the cellular composition and cell-type-specific gene expression in the PMN kidney. The complement-induced BMP2/pSMAD1/COL4 pathway is identified as the pathogenic pathway in podocytes, bridging two key events, i.e., complement system activation and glomerular basement membrane thickening in PMN. Augmented infiltration and activation of myeloid leukocytes and B lymphocytes are found, profiling delicate crosstalk of immune cells in PMN kidneys. Overall, these results provide valuable insights into the roles of podocytes and immune cells in PMN, and comprehensive resources toward the complete understanding of PMN pathophysiology.

Klotho Stabilizes the Podocyte Actin Cytoskeleton in Idiopathic Membranous Nephropathy through Regulating the TRPC6/CatL Pathway

INTRODUCTION

The aim of this study was to explore the renoprotective effects of Klotho on podocyte injury mediated by complement activation and autoantibodies in idiopathic membranous nephropathy (IMN).

METHODS

Rat passive Heymann nephritis (PHN) was induced as an IMN model. Urine protein levels, serum biochemistry, kidney histology, and podocyte marker levels were assessed. In vitro, sublytic podocyte injury was induced by C5b-9. The expression of Klotho, transient receptor potential channel 6 (TRPC6), and cathepsin L (CatL); its substrate synaptopodin; and the intracellular Ca2+ concentration were detected via immunofluorescence. RhoA/ROCK pathway activity was measured by an activity quantitative detection kit, and the protein expression of phosphorylated-LIMK1 (p-LIMK1) and p-cofilin in podocytes was detected via Western blotting. Klotho knockdown and overexpression were performed to evaluate its role in regulating the TRPC6/CatL pathway.

RESULTS

PHN rats exhibited proteinuria, podocyte foot process effacement, decreased Klotho and Synaptopodin levels, and increased TRPC6 and CatL expression. The RhoA/ROCK pathway was activated by the increased phosphorylation of LIMK1 and cofilin. Similar changes were observed in C5b-9-injured podocytes. Klotho knockdown exacerbated podocyte injury, while Klotho overexpression partially ameliorated podocyte injury.

CONCLUSION

Klotho may protect against podocyte injury in IMN patients by inhibiting the TRPC6/CatL pathway. Klotho is a potential target for reducing proteinuria in IMN patients.

Colquhounia root tablet in the treatment of idiopathic membranous nephropathy with subnephrotic proteinuria

PURPOSE

Idiopathic membranous nephropathy (IMN) is the most frequent global cause of nephrotic syndrome in non-diabetic people. In clinical practice, An effective and mild treatment for IMN patients with subnephrotic proteinuria has been adopted. Colquhounia root tablet (CRT) is a traditional Chinese medicine that is widely used in China to treat glomerulopathies. In this study, the effectiveness and safety of CRT in the treatment of IMN with subnephrotic proteinuria have been determined by reviewing the clinical records of 44 patients with IMN.

METHODS

Retrospective analysis of IMN patients with subnephrotic proteinuria treated with CRT in combination with ACEI/ARB or ACEI/ARB alone. The remission rate (complete or partial remission) was the main outcome observed, and proteinuria, estimated glomerular filtration rate (eGFR), serum albumin levels, and adverse effects were the secondary outcomes.

RESULTS

This clinical trial included 44 patients, and the overall remission rates at months 6, 9, and 12 after treatment were 68.2% versus 27.3% (p = 0.016), 72.7% versus 36.4% (p = 0.015), and 77.3% versus 36.4% (p = 0.006) in the treatment and control groups, respectively. The application of CRT treatment was an independent predictor of proteinuria remission (p = 0.024). In addition, in patients who were positive for phospholipase A2 receptor (PLA2R) antibodies, the overall remission rate was higher in the treatment group than in the control group after 9 months of treatment (75% versus 23.08%, p = 0.017).

CONCLUSION

This retrospective study illustrates that, based on supportive therapy, CRT could be effective in the treatment of IMN with subnephrotic proteinuria with a good safety profile at the same time.

Application of nanotechnology in the treatment of glomerulonephritis: current status and future perspectives

Glomerulonephritis (GN) is the most common cause of end-stage renal failure worldwide; in most cases, it cannot be cured and can only delay the progression of the disease. At present, the main treatment methods include symptomatic therapy, immunosuppressive therapy, and renal replacement therapy. However, effective treatment of GN is hindered by issues such as steroid resistance, serious side effects, low bioavailability, and lack of precise targeting. With the widespread application of nanoparticles in medical treatment, novel methods have emerged for the treatment of kidney diseases. Targeted transportation of drugs, nucleic acids, and other substances to kidney tissues and even kidney cells through nanodrug delivery systems can reduce the systemic effects and adverse reactions of drugs and improve treatment effectiveness. The high specificity of nanoparticles enables them to bind to ion channels and block or enhance channel gating, thus improving inflammation. This review briefly introduces the characteristics of GN, describes the treatment status of GN, systematically summarizes the research achievements of nanoparticles in the treatment of primary GN, diabetic nephropathy and lupus nephritis, analyzes recent therapeutic developments, and outlines promising research directions, such as gas signaling molecule nanodrug delivery systems and ultrasmall nanoparticles. The current application of nanoparticles in GN is summarized to provide a reference for better treatment of GN in the future.

Minnelide Markedly Reduces Proteinuria in Mice with Adriamycin Nephropathy by Protecting Against Podocyte Injury

Minimal change disease (MCD) is the most common cause of idiopathic nephrotic syndrome in children. The current major therapy is hormones for most steroid-sensitive patients. However, many patients have recurrent relapses of the disease and require long-term immunosuppression, leading to significant morbidity due to the side effects of the drugs. Therefore, better drugs need to be urgently explored to treat nephrotic syndrome while avoiding the side effects of drugs. Minnelide, a water-soluble prodrug of triptolide, has been proved to be effective in treating cancers in many clinical trials. This study aimed to investigate the therapeutic effect of minnelide in mice with adriamycin (ADR) nephropathy, its underlying protection mechanisms, and its reproductive toxicity. Minnelide was administered intraperitoneally to 6-8-week female mice with adriamycin nephropathy for 2 weeks, and the urine, blood, and kidney tissues were taken to analyze the therapeutic effect. In addition, we evaluated reproductive toxicity by measuring the levels of gonadal hormones and observing the histological changes in ovaries and testes. Primary mouse podocytes were exposed to puromycin (PAN) to damage the cytoskeleton and induce apoptosis, and then, triptolide was used to evaluate the therapeutic effect and underlying protection mechanisms in vitro. It was observed that minnelide dramatically alleviated proteinuria and apoptosis in mice with adriamycin nephropathy. In vitro, triptolide ameliorated puromycin-induced cytoskeletal rearrangement and apoptosis via reactive oxygen species-mediated mitochondrial pathway. In addition, minnelide caused no reproductive toxicity to male and female mice. The results suggested that minnelide might be a promising drug for nephrotic syndrome.

Biofactors regulating mitochondrial function and dynamics in podocytes and podocytopathies

Podocytes are terminally differentiated kidney cells acting as the main gatekeepers of the glomerular filtration barrier; hence, inhibiting proteinuria. Podocytopathies are classified as kidney diseases caused by podocyte damage. Different genetic and environmental risk factors can cause podocyte damage and death. Recent evidence shows that mitochondrial dysfunction also contributes to podocyte damage. Understanding alterations in mitochondrial metabolism and function in podocytopathies and whether altered mitochondrial homeostasis/dynamics is a cause or effect of podocyte damage are issues that need in-depth studies. This review highlights the roles of mitochondria and their bioenergetics in podocytes. Then, factors/signalings that regulate mitochondria in podocytes are discussed. After that, the role of mitochondrial dysfunction is reviewed in podocyte injury and the development of different podocytopathies. Finally, the mitochondrial therapeutic targets are considered.

Efficacy and safety of Tripterygium wilfordii multiglucoside for idiopathic membranous nephropathy: a systematic review with bayesian meta-analysis

Background: Currently, the optimal therapy plan for idiopathic membranous nephropathy (IMN) remains controversial as there has been no comprehensive and systematic comparison of therapy plans for IMN. Therefore, in this study, a Bayesian meta-analysis was used to systematically evaluate the clinical efficacy and safety of various intervention plans involving traditional Chinese medicine TWM in the treatment of IMN. Methods: An electronic search in 7 databases was conducted from their inception to August 2022 for all published randomized controlled trials (RCTs) of various intervention plans for IMN. Network meta-analysis (NMA) was performed by using software R, and the surface under the cumulative ranking area (SUCRA) probability curve was plotted for each outcome indicator to rank the efficacy and safety of different intervention plans. Results: A total of 30 RCTs were included, involving 13 interventions. The results showed that (1) in terms of total remission (TR), ① GC + CNI + TWM was the best effective among all plans, and the addition and subtraction plan of CNI + TWM was the best effective for IMN; ② All plans involving TWM were more effective than GG; ③ Among monotherapy plans for IMN, TWM was more effective distinctly than GC, while TWM and CNI were similarly effective; ④ Among multidrug therapy plans for IMN, the addition of TWM to previously established therapy plans made the original plans more effective; ⑤The efficacy of combining TWM with other plans was superior to that of TWM alone. (2) In terms of lowering 24 h-UTP, GC + TWM was the best effective and more effective than TWM. (3) In terms of safety, there was no statistically significant difference between all groups. However, CNI + TWM was the safest. No serious adverse events (AEs) occurred in all the included studies. Conclusion: The addition of TWM may be beneficial to patients with IMN. It may enhance the efficacy of previously established treatment protocols without leading to additional safety risks. In particular, GC + CNI + TWM, GC + TWM, and CNI + TWM with better efficacy and higher safety can be preferred in clinical decision-making as the therapy plans for IMN.

Kunxian capsule alleviates podocyte injury and proteinuria by inactivating β-catenin in db/db mice

Background

Diabetic kidney disease (DKD) remains the primary cause of end-stage renal disease (ESRD) globally, but treatment options are limited. Kunxian capsule (KXC) has been utilized for the treatment of autoimmune diseases and IgA nephropathy in China. However, its effect on DKD remains poorly investigated. Therefore, this study aimed to explore the protective effect of KXC in db/db mice and elucidate its underlying mechanism.

Methods

The renoprotective effects of KXC were assessed in a DKD mouse model using male BKS db/db diabetic mice. After 8 weeks of treatment, the urinary albumin-to-creatinine ratio (UACR), blood biochemical parameters, renal histopathological manifestation, and podocyte ultrastructural changes were evaluated. Additionally, the expression of podocyte epithelial-to-mesenchymal transition (EMT) markers [WT1, ZO-1, and collogen I (Col1a1)] was quantitatively analyzed. Furthermore, we explored the role of KXC in the β-catenin signaling pathway to elucidate the underlying mechanism of KXC's renoprotective effect.

Results

KXC treatment effectively reduced albuminuria and attenuated renal structural abnormalities in db/db mice. Additionally, KXC restored the protein and mRNA expression of WT1 and ZO-1 while suppressing the expression of Col1a1 in db/db mice, indicating its ability to alleviate podocyte EMT. Mechanistically, KXC exerted a significant suppressive effect on the activation of β-catenin signaling in diabetic kidneys.

Conclusion

KXC has the potential to protect podocytes during DKD by alleviating podocyte EMT through inactivating β-catenin signaling.

Friend or foe? The dual role of triptolide in the liver, kidney, and heart

Triptolide, a controversial natural compound due to its significant pharmacological activities and multiorgan toxicity, has gained much attention since it was isolated from the traditional Chinese herb Tripterygium wilfordii Hook F. However, in addition to its severe toxicity, triptolide also presents powerful therapeutic potency in the same organs, such as the liver, kidney, and heart, which corresponds to the Chinese medicine theory of You Gu Wu Yun (anti-fire with fire) and deeply interested us. To determine the possible mechanisms involved in the dual role of triptolide, we reviewed related articles about the application of triptolide in both physiological and pathological conditions. Inflammation and oxidative stress are the two main ways triptolide exerts different roles, and the cross-talk between NF-κB and Nrf2 may be one of the mechanisms responsible for the dual role of triptolide and may represent the scientific connotation of You Gu Wu Yun. For the first time, we present a review of the dual role of triptolide in the same organ and propose the possible scientific connotation of the Chinese medicine theory of You Gu Wu Yun, hoping to promote the safe and efficient use of triptolide and other controversial medicines.

Minnelide combined with Angptl3 knockout completely protects mice with adriamycin nephropathy via suppression of TGF-β1-Smad2 and p53 pathways

Minimal change disease (MCD) is the common type of nephrotic syndrome in children. There is an urgent need to explore new treatment methods as current treatments have many drawbacks and cause significant side effects. Our group found that Angiopoietin-like protein 3 (Angptl3) is closely related to renal disease and Angptl3 knockout significantly alleviated proteinuria in mice with adriamycin nephropathy (AN), however, some proteinuria was still present. Minnelide is a water-soluble prodrug of triptolide which has been used for the treatment of glomerular diseases. Therefore, this study aimed to investigate whether minnelide, combined with Angptl3 knockout, could completely protect mice with AN and its mechanism. AN was induced in B6;129S5 female mice by tail vein injection of 25 mg/kg of Adriamycin (ADR), and treatment with 200 ug/kg/d of minnelide. The results showed that minnelide combined with Angptl3 knockout completely reduced proteinuria and restored the foot processes in mice with AN. Moreover, in Angptl3 knockout mice with AN, minnelide restored the distribution of nephrin, podocin and cd2ap and reduced inflammatory factors (Tumor necrosis factor alpha (TNF-α), Interleukin-6 (IL-6) and Interleukin-1β (IL-1β)). Through RNA sequencing and related experiments, we found minnelide could ameliorate fibrosis and apoptosis by inhibiting TGF-β1-Smad2 and p53 pathways in Angptl3 knockout mice with AN, respectively. In Angptl3 knockout primary podocytes, triptolide alleviates ADR-induced decreases in nephrin, podocin and cd2ap, upregulation of Bax and downregulation of Bcl-2. Overall, our study shows that minnelide combined with Angptl3 knockout completely protects mice with AN by inhibiting the TGF-β1-smad2 and p53 pathways.

Triptolide Attenuates Muscular Inflammation and Oxidative Stress in a Delayed-Onset Muscle Soreness Animal Model

Delayed-onset muscle soreness (DOMS) is associated with exercise-induced muscle damage and inflammation, which is mainly caused by prolonged eccentric exercise in humans. Triptolide, an extract from the Chinese herb Tripterygium wilfordii Hook F, has been used for treating autoimmune and inflammatory diseases in clinical practice. However, whether triptolide attenuates acute muscle damage is still unclear. Here, we examined the effect of triptolide on carrageenan-induced DOMS in rats. Rats were injected with 3% of carrageenan into their muscles to induce acute left gastrocnemius muscular damage, and triptolide treatment attenuated carrageenan-induced acute muscular damage without affecting hepatic function. Triptolide can significantly decrease lipid hydroperoxide and nitric oxide (NO) levels, proinflammatory cytokine production, and the activation of nuclear factor (NF)-ĸB, as well as increase a reduced form of glutathione levels in carrageenan-treated rat muscles. At the enzyme levels, triptolide reduced the inducible nitric oxide synthase (iNOS) expression and muscular myeloperoxidase (MPO) activity in carrageenan-treated DOMS rats. In conclusion, we show that triptolide can attenuate muscular damage by inhibiting muscular oxidative stress and inflammation in a carrageenan-induced rat DOMS model.

Role of Alternative Medical Systems in Adult Chronic Kidney Disease Patients: A Systematic Review of Literature

There is a growing interest in the use of alternative medical systems (AMS), such as traditional Chinese medicine (TCM), ayurveda, homeopathy, and naturopathy, among chronic kidney disease patients. This review summarizes the efficacy and safety of AMS interventions in chronic kidney disease (CKD) patients. A systematic review was conducted in MEDLINE, Embase, Scopus, CINAHL, CENTRAL, and PsycINFO in line with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) and Synthesis without meta-analysis (SWiM) guidelines. Randomized controlled trials (RCTs) which evaluated the use of AMS among adult CKD patients were included. The efficacy of each AMS was assessed based on improvement in biochemical markers or reduction in symptom severity scores. All adverse reactions were recorded. Of the 14,583 articles retrieved, 33 RCTs were included. TCM (n=20) and ayurveda (n=6) were the most well-studied. Majority of studies (66.7%) had a sample size <100. Common indications evaluated included improvement in renal function (n=12), proteinuria (n=5), and uremic pruritus (n=5). Among TCM, acupuncture and syndromes-based TCM granules formulation were shown to improve estimated glomerular filtration rate (eGFR) by 5.1-15.5% and 7.07-8.12% respectively. Acupuncture reduced uremic pruritus symptoms by 54.7-60.2% while Huangkui, Shenqi granules, and Tripterygium wilfordii Hook F reduced proteinuria by 18.6-50.7%, 61.8%, and 32.1% respectively. For Ayurveda, camel milk and Nigella sativa oil improved eGFR by 16.9% and 86.8%, respectively, while capsaicin reduced pruritus scores by 84.3%. Homeopathic verum medication reduced pruritus scores by 29.2-41.5%. Nausea was the most common adverse effect reported with alpha-keto amino acids (0.07%), Nigella sativa oil (7.04%), and silymarin (10%). TCM and ayurveda were more well-studied AMS therapies that demonstrated efficacy in CKD patients. RCTs with larger sample sizes are needed to ascertain the efficacy and safety of promising AMS.

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.

The critical role of the Hippo signaling pathway in kidney diseases

The Hippo signaling pathway is involved in cell growth, proliferation, and apoptosis, and it plays a key role in regulating organ size, tissue regeneration, and tumor development. The Hippo signaling pathway also participates in the occurrence and development of various human diseases. Recently, many studies have shown that the Hippo pathway is closely related to renal diseases, including renal cancer, cystic kidney disease, diabetic nephropathy, and renal fibrosis, and it promotes the transformation of acute kidney disease to chronic kidney disease (CKD). The present paper summarizes and analyzes the research status of the Hippo signaling pathway in different kidney diseases, and it also summarizes the expression of Hippo signaling pathway components in pathological tissues of kidney diseases. In addition, the present paper discusses the positive therapeutic significance of traditional Chinese medicine (TCM) in regulating the Hippo signaling pathway for treating kidney diseases. This article introduces new targets and ideas for drug development, clinical diagnosis, and treatment of kidney diseases.

Mechanism of Tripterygium wilfordii Hook.F.- Trichosanthes kirilowii Maxim decoction in treatment of diabetic kidney disease based on network pharmacology and molecular docking

Background: Diabetic kidney disease (DKD) is the most common cause of end-stage renal disease. The effective treatment of DKD would rely on the incorporation of a multi-disciplinary. Studies have shown that Tripterygium wilfordii Hook.F. and Trichosanthes kirilowii Maxim have remarkable curative effects in treating DKD, but their combination mechanism has not been fully elucidated.

Methods: We explored the mechanism of Tripterygium wilfordii Hook.F.-Trichosanthes kirilowii Maxim decoction (Leigongteng-Tianhuafen Decoction,LTD) in the treatment of DKD by network pharmacology and molecular docking. The main active components and action targets of LTD were collected from Traditional Chinese Medicine Systems Pharmacology Database and Analysis Platform (TCMSP) database. The speculative targets of DKD were obtained from GeneCards, DisGeNET, and Online Mendelian Inheritance in Man (OMIM) databases. Then, an herb-component-target network was constructed based on the above analyses. The biological function of targets was subsequently investigated, and a protein-protein interaction (PPI) network was constructed to identify hub targets of DKD. The gene ontology (GO) function enrichment analysis and kyoto encyclopedia of genes and genomes (KEGG) pathway enrichment analysis were performed by RStudio. Finally, molecular docking was performed by AutoDock Vina and PyMOL software to explore the interaction between compounds and targets. Furthermore, the DKD model of human renal tubular cells (HK-2) induced by high glucose (HG) was selected, and the predicted results were verified by western blot analysis and immunofluorescence.

Results: A total of 31 active components of LTD were screened out, and 196 targets were identified based on the TCMSP database. A total of 3,481 DKD related targets were obtained based on GeneCards, DisGeNET, and OMIM databases. GO function enrichment analysis included 2,143, 50, and 167 GO terms for biological processes (BPs), cellular composition (CCs), and molecular functions (MFs), respectively. The top 10 enrichment items of BP annotations included response to lipopolysaccharide, response to molecule of bacterial origin, response to extracellular stimulus, etc. CC was mainly enriched in membrane raft, membrane microdomain, plasma membrane raft, etc. The MF of LTD analysis on DKD was predominately involved in nuclear receptor activity, ligand-activated transcription factor activity, RNA polymerase II-specific DNA-binding transcription factor binding, etc. The involvement signaling pathway of LTD in the treatment of DKD included AGE-RAGE signaling pathway in diabetic complications, IL-17 signaling pathway, insulin resistance, TNF signaling pathway, etc. Molecular docking results showed that kaempferol, triptolide, nobiletin, and schottenol had a strong binding ability to PTGS2 and RELA. Furthermore, the in vitro experiments confirmed that LTD effectively decreased the expression of PTGS2, NF-κB, JNK, and AKT in the HG-induced DKD model.

Conclusion: The findings of this study revealed that the therapeutic efficacy of LTD on DKD might be achieved by decreasing the expression of PTGS2, NF-κB, JNK, and AKT, which might improve insulin resistance, inflammation, and oxidative stress. These findings can provide ideas and supply potential therapeutic targets for DKD.

Triptolide promotes autophagy to inhibit mesangial cell proliferation in IgA nephropathy via the CARD9/p38 MAPK pathway

Background

Mesangial cell proliferation is the most basic pathological feature of immunoglobulin A nephropathy (IgAN); however, the specific underlying mechanism and an appropriate therapeutic strategy are yet to be unearthed. This study aimed to investigate the therapeutic effect of triptolide (TP) on IgAN and the mechanism by which TP regulates autophagy and proliferation of mesangial cells through the CARD9/p38 MAPK pathway.

Methods

We established a TP‐treated IgAN mouse model and produced IgA1‐induced human mesangial cells (HMC) and divided them into control, TP, IgAN, and IgAN+TP groups. The levels of mesangial cell proliferation (PCNA, cyclin D1, cell viability, and cell cycle) and autophagy (P62, LC3 II, and autophagy flux rate) were measured, with the autophagy inhibitor 3‐Methyladenine used to explore the relationship between autophagy and proliferation. We observed CARD9 expression in renal biopsies from patients and analyzed its clinical significance. CARD9 siRNA and overexpression plasmids were constructed to investigate the changes in mesangial cell proliferation and autophagy as well as the expression of CARD9 and p‐p38 MAPK/p38 MAPK following TP treatment.

Results

Administering TP was safe and effectively alleviated mesangial cell proliferation in IgAN mice. Moreover, TP inhibited IgA1‐induced HMC proliferation by promoting autophagy. The high expression of CARD9 in IgAN patients was positively correlated with the severity of HMC proliferation. CARD9/p38 MAPK was involved in the regulation of HMC autophagy and proliferation, and TP promoted autophagy to inhibit HMC proliferation by downregulating the CARD9/p38 MAPK pathway in IgAN.

Conclusion

TP promotes autophagy to inhibit mesangial cell proliferation in IgAN via the CARD9/p38 MAPK pathway.

Effectiveness and safety of KunXian capsule for the treatment of IgA nephropathy

BACKGROUND

Tripterygium Wilfordii Hook F (TwHF) preparation has been widely used in the treatments of IgA nephropathy (IgAN) in China. However, the effectiveness and safety of the new generation of TwHF preparation, KuxXian capsule, on the treatment of IgAN remains unknown.

METHODS

Here, we retrospectively describe our experience treating 55 consecutive IgAN patients with KunXian. We defined complete remission as proteinuria < 0.5 g/24 h and partial remission as proteinuria < 1 g/24 h, each also having > 50% reduction in proteinuria from baseline.

RESULTS

At first follow-up after KunXian treatment (5.7 weeks, IQR 4.7-7.9), all but two patients (96%) showed a reduction in proteinuria. The overall median proteinuria decreased from 2.23 g/day at baseline to 0.94 g/day (P < 0.001) at the first follow-up. During a median follow-up of 28 weeks after KunXian administration, 25(45.5%) patients achieved complete remission, 34 (61.8%) patients achieved complete/partial remission. Of the 12 patients discontinued KunXian treatment during the follow-up, the median proteinuria was increased from 0.97 g/24 h to 2.74 g/24 h after a median of 10.9 weeks (P = 0.004). Multivariable Cox models showed that female, treatment switching from previous generation of TwHF preparation, lower initial KunXian dosage, and higher proteinuria at baseline were independently associated proteinuria remission. Of the 20 pre-menopausal females, 12 of them developed oligomenorrhea or menstrual irregularity and ten of them developed amenorrhea.

CONCLUSION

KunXian is effectiveness and safety for the treatment of IgA nephropathy. Woman of childbearing age to be informed of the risk of ovarian failure after being treated with TwHF preparations.

Mitochondrial Oxidative Stress and Cell Death in Podocytopathies

Podocytopathies are kidney diseases that are driven by podocyte injury with proteinuria and proteinuria-related symptoms as the main clinical presentations. Albeit podocytopathies are the major contributors to end-stage kidney disease, the underlying molecular mechanisms of podocyte injury remain to be elucidated. Mitochondrial oxidative stress is associated with kidney diseases, and increasing evidence suggests that oxidative stress plays a vital role in the pathogenesis of podocytopathies. Accumulating evidence has placed mitochondrial oxidative stress in the focus of cell death research. Excessive generated reactive oxygen species over antioxidant defense under pathological conditions lead to oxidative damage to cellular components and regulate cell death in the podocyte. Conversely, exogenous antioxidants can protect podocyte from cell death. This review provides an overview of the role of mitochondrial oxidative stress in podocytopathies and discusses its role in the cell death of the podocyte, aiming to identify the novel targets to improve the treatment of patients with podocytopathies.

Mechanism of action of Tripterygium wilfordii for treatment of idiopathic membranous nephropathy based on network pharmacology

Background

Although thunder god vine (Tripterygium wilfordii) has been widely used for treatment of idiopathic membranous nephropathy (IMN), the pharmacological mechanisms underlying its effects are still unclear. This study investigated potential therapeutic targets and the pharmacological mechanism of T. wilfordii for the treatment of IMN based on network pharmacology.

Methods

Active components of T. wilfordii were obtained from the Traditional Chinese Medicine Systems Pharmacology Database and Analysis Platform. IMN-associated target genes were collected from the GeneCards, DisGeNET, and OMIM databases. VENNY 2.1 was used to identify the overlapping genes between active compounds of T. wilfordii and IMN target genes. The STRING database and Cytoscape 3.7.2 software were used to analyze interactions among overlapping genes. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analyses of the targets were performed using Rx64 4.0.2 software, colorspace, stringi, DOSE, clusterProfiler, and enrichplot packages.

Results

A total of 153 compound-related genes and 1485 IMN-related genes were obtained, and 45 core genes that overlapped between both categories were identified. The protein–protein interaction network and MCODE results indicated that the targets TP53, MAPK8, MAPK14, STAT3, IFNG, ICAM1, IL4, TGFB1, PPARG, and MMP1 play important roles in the treatment of T. wilfordii on IMN. Enrichment analysis showed that the main pathways of targets were the AGE signaling pathway, IL-17 signaling pathway, TNF signaling pathway, and Toll-like receptor signaling pathway.

Conclusion

This study revealed potential multi-component and multi-target mechanisms of T. wilfordii for the treatment of IMN based on network pharmacological, and provided a scientific basis for further experimental studies.

Triptolide Alleviates Podocyte Epithelial-Mesenchymal Transition via Kindlin-2 and EMT-Related TGF-β/Smad Signaling Pathway in Diabetic Kidney Disease

Diabetes-induced chronic kidney diseases are widespread and decrease the quality of life for millions of affected individuals in China. To date, no therapies effectively alleviate these conditions. Triptolide, a traditionally used Chinese medicine, has shown promise in treating renal diseases. Here, the study aimed to decipher the exact mechanism by which it functions. It was hypothesized that triptolide might prevent the epithelial-mesenchymal transition (EMT) of podocytes by activating the kindlin-2 and TGF-β/Smad pathways. Triptolide or telmisartan was intragastrically administered to 9-week-old db/db and dm/dm mice with diabetic nephropathy (DN) for 12 weeks. In addition, biochemical parameters and body weight were detected. WT-1, nephrin, podocin, E-cadherin, and α-SMA were determined by immunohistochemistry in the renal tissues of treated mice. Protein and mRNA expression of podocyte EMT markers, kindlin-2 and TGF-β/Smad, were analyzed to elucidate the underlying mechanism. It was observed that triptolide treatment relieved structural injuries and functional variations in diabetic mice. It also increased the protein and mRNA levels of nephrin, podocin, and E-cadherin and decreased the expression of α-SMA in diabetic mice. The protein and mRNA expressions of TGF-β1, p-SMAD3, and kindlin-2 decreased in diabetic kidneys following triptolide treatment. The findings demonstrated that triptolide might protect podocytes during DN by inhibiting podocyte EMT through inactivation of kindlin-2, combined with the downregulation of P-SMAD3 in the TGF-β/Smad signaling pathway.

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.

Efficacy of Tripterygium wilfordii Hook F on animal model of Diabetic Kidney Diseases: A systematic review and meta-analysis

ETHNOPHARMACOLOGICAL RELEVANCE

Tripterygium wilfordii Hook F (TwHF) has been clinically applied in the treatment of Diabetic Kidney Diseases (DKD). A large number of animal experiments focused on the TwHF treatment of DKD were conducted every year, but the evidence for these preclinical studies is unclear.

AIM OF THE STUDY

This study aims to evaluate the efficacy of TwHF on diabetic nephropathy through a stematic reviews and meta-analysis of animal models, and whether it has an effect on improving kidney pathology, renal function indicators and blood sugar levels, it also summarizes the use of TwHF for treatment the underlying mechanism of DKD.

MATERIALS AND METHODS

We systematically searched studies from PubMed, Web of Science, Embase, China National Knowledge Infrastructure (CNKI), China Science and Technology Journal Database (VIP), and Wanfang database from inception to May 2020. Chinese studies from the list of Chinese Core Journals would be included. SYRCLE's risk of bias tool for animal studies was applied to assess the methodological quality of studies. A meta-analysis was performed by using RevMan 5.3.

RESULTS

Out of 429 records identified in the initial search, 32 studies were selected. The results indicated that, compared with control group, TwHF treatment improved 24 h urine protein (24 h-UP) level (SMD - 4.21, 95% CI - 5.38 to - 3.04, P < 0.001), serum creatinine (Scr) (MD - 14.97, 95% CI - 20.42 to - 9.53, P < 0.001), blood urea nitrogen (BUN) (MD - 4.07, 95% CI - 5.49 to - 2.66, P < 0.001), blood glucose (Glu) (MD - 2.40, 95% CI - 4.304 to - 0.49, P = 0.01), Triglyceride (TG) (MD - 1.57, 95% CI - 2.06 to - 1.08, P < 0.001), and Cholesterol (TC) (MD - 1.49, 95% CI - 2.23 to - 0.75 P < 0.001); and increased the level of albumin (Alb) (MD 3.40, 95% CI 1.69 to 5.11, P < 0.001) and weight (MD 30.89, 95% CI 24.35 to 37.42, P < 0.001). There were no statistical difference on Alanine aminotransferase (ALT) (MD 3.00, 95% CI - 7.80 to 13.81, P = 0.59) and Aspartate aminotransferase (AST) (MD 0.77, 95% CI -15.05 to 16.60, P = 0.92) after TwHF. Meta regression analysis showed that the DKD model induced by different methods (type I/II), the dose of Tripterygium wilfordii and the intervention time were not the reasons for the heterogeneity of 24 h-UP, Alb, Glu, Scr, and BUN (p > 0.05).

CONCLUSIONS

TwHF is an effective and safe to treat DKD, which can protect the kidneys through anti-inflammation, improving oxidative stress and podocyte damage, and inhibiting mesangial cell proliferation and extracellular matrix proliferation.

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.

Retrospective analysis of Tripterygium wilfordii polyglycoside combined with angiotensin receptor blockers for the treatment of primary membranous nephropathy with sub-nephrotic proteinuria

INTRODUCTION

Primary membranous nephropathy (PMN) is one common cause of end-stage kidney disease. There is no optimal treatment for PMN patients with sub-nephrotic proteinuria currently. Tripterygium wilfordii polyglycoside (TWG) is a widely used traditional medicine in China and has been used to treat nephropathy for decades.

OBJECTIVE

To investigate the effect of TWG combined with angiotensin receptor blocker (ARB) on the treatment of PMN with sub-nephrotic proteinuria.

METHODS

Biopsy-proven sub-nephrotic PMN patients with normal kidney function and treated with TWG combined with ARB or ARB alone were retrospectively analyzed. The primary outcome was remission rate (complete or partial remission), and the secondary outcomes included proteinuria, serum albumin levels, estimated glomerular filtration rate (eGFR), relapse rate, and adverse events.

RESULTS

The clinical trial included 55 patients. The overall remission rates for the TWG + ARB and ARB groups after 9 months of treatment were 74.3% and 35%, respectively (p = 0.004). Moreover, the complete remission (CR) rate for the TWG + ARB and ARB groups in the 9th month were 45.7% and 15%, respectively (p = 0.044). Treatment with TWG + ARB was the independent predictor of complete remission of proteinuria (p = 0.048). Besides, the remission rate was higher in the TWG + ARB group than in the ARB group among patients who were positive for anti-phospholipase A2 receptor (PLA2R) antibodies (65.4% vs. 21.4%, p = 0.02).

CONCLUSIONS

These data demonstrate that TWG may be a promising treatment for PMN patients with sub-nephrotic proteinuria, whether anti-PLA2R antibody is positive or negative.

Integrin β3 Induction Promotes Tubular Cell Senescence and Kidney Fibrosis

Tubular cell senescence is a common biologic process and contributes to the progression of chronic kidney disease (CKD); however, the molecular mechanisms regulating tubular cell senescence are poorly understood. Here, we report that integrin β3 (ITGB3) expression was increased in tubular cells and positively correlated with fibrosis degree in CKD patients. ITGB3 overexpression could induce p53 pathway activation and the secretion of TGF-β, which, in turn, resulted in senescent and profibrotic phenotype change in cultured tubular cells. Moreover, according to the CMAP database, we identified isoliquiritigenin (ISL) as an agent to inhibit ITGB3. ISL treatment could suppress Itgb3 expression, attenuate cellular senescence, and prevent renal fibrosis in mice. These results reveal a crucial role for integrin signaling in cellular senescence, potentially identifying a new therapeutic direction for kidney fibrosis.

Biomarker Identification in Membranous Nephropathy Using a Long Non-coding RNA-Mediated Competitive Endogenous RNA Network

PURPOSE

This study was aimed to identify biomarker associated with membranous nephropathy (MN) progression by integration of expression profiles and competitive endogenous RNA (ceRNA) network analysis.

METHODS

The gene (GSE108113) and microRNAs (miRNAs) expression profiles (GSE64306) were downloaded to identify the differentially expressed mRNAs, miRNAs and long non-coding RNAs (lncRNAs) between MN and control groups. The functions and pathways enriched by the differentially expressed mRNAs were analyzed. The mRNA-lncRNA co-expression network was constructed followed by and the ceRNA network construction.

RESULTS

Total 264 upregulated and 196 downregulated differentially expressed mRNAs, 79 upregulated and 4 downregulated lncRNAs, as well as 115 upregulated and 93 downregulated miRNAs were obtained between MN and control groups. After analysis, the differential mRNAs were significantly involved in multiple immune-related processes, and cell proliferation, apoptosis and differentiation processes, as well as pathways of taste transduction and lysosome. Finally, a ceRNA network consisting of 4 mRNAs (EPB41L5, FAM43A, PRKG1 and TTC14), 3 lncRNAs (LINC00052, LINC00641 and N4BP2L2-IT2) and 5 miRNAs (hsa-miR-145-5p, hsa-miR-3605-5p, hsa-miR-148a-3p, hsa-miR-497-5p and hsa-miR-148b-3p) was constructed.

CONCLUSION

Our study indicated dysregulation of immune- and apoptosis-associated functions and taste transduction and lysosome pathways may play important roles in MN progression. Deregulated ceRNAs, such as LINC00052-hsa-miR-145-5p-EPB41L5, LINC00052-hsa-miR-148a-3p-FAM43A and LINC00641-hsa-497-5p-PRKG1, may be associated with MN development.

Natural product therapies in chronic kidney diseases: An update

Chronic kidney disease is one of the major worldwide public health problems. Traditional Chinese medications have been widely used for chronic kidney disease treatment. As the development of modern phytochemistry technology, natural products have been isolated from traditional Chinese medications, which provide a more precise method for the investigation of traditional Chinese medications. In this article, we selected eight natural products from traditional Chinese medications for chronic kidney disease therapy to summarize the recent advances for the development of new medications.

Tripterygium glycoside suppresses epithelial‑to‑mesenchymal transition of diabetic kidney disease podocytes by targeting autophagy through the mTOR/Twist1 pathway

Tripterygium glycoside (TG) is a traditional Chinese medicine extract with immunosuppressive, anti-inflammatory and anti-renal fibrosis effects. Epithelial-mesenchymal transition (EMT) and cell apoptosis are considered to be the major cause of podocyte injury in diabetic kidney disease (DKD). However, it remains unknown as to whether TG is able to alleviate podocyte injury to prevent DKD progression. Therefore, the present study aimed to clarify the podocyte protective effects of TG on DKD. TG, Twist1 small interfering RNA (siRNA) and Twist1 overexpression vector were added to DKD mouse serum-induced podocytes in vitro. Autophagic and EMT activities were evaluated by immunofluorescence staining and western blot analysis. Apoptotic activity was evaluated by Annexin V-FITC/PI flow cytometric analysis. The results revealed that after treatment with DKD mouse serum, autophagy was decreased, whereas EMT and apoptotic rate were increased, in podocytes. In addition, Twist1 expression was increased in DKD-induced podocytes. Furthermore, following Twist1-small interfering RNA transfection, the DKD-induced podocyte EMT and apoptotic rate were markedly reduced, indicating that Twist1 may be a promising therapeutic target for DKD. The present results also revealed that overexpression of Twist1 increased podocyte apoptosis, although this was decreased after TG treatment, indicating that TG may exhibit a protective effect on podocytes by inhibiting the Twist1 signaling pathway. After the addition of 3-benzyl-5-((2-nitrophenoxy) methyl)-dihydrofuran-2(3H)-one, an activator of mTORC1, the effects of TG on podocyte EMT, apoptosis and the autophagy were reversed. These findings indicated that TG may alleviate EMT and apoptosis by upregulating autophagy through the mTOR/Twist1 signaling pathway in DKD.

Study of the Active Components and Molecular Mechanism of Tripterygium wilfordii in the Treatment of Diabetic Nephropathy

We aimed to explore the active ingredients and molecular mechanism of Tripterygium wilfordii (TW) in the treatment of diabetic nephropathy (DN) through network pharmacology and molecular biology. First, the active ingredients and potential targets of TW were obtained through the Traditional Chinese Medicine Systems Pharmacology Database and Analysis Platform (TCMSP) and related literature materials, and Cytoscape 3.7.2 software was used to construct the active ingredient-target network diagram of TW. Second, the target set of DN was obtained through the disease database, and the potential targets of TW in the treatment of DN were screened through a Venn diagram. A protein interaction network diagram (PPI) was constructed with the help of the String platform and Cytoscape 3.7.2. Third, the ClueGO plug-in tool was used to enrich the GO biological process and the KEGG metabolic pathway. Finally, molecular docking experiments and cell pathway analyses were performed. As a result, a total of 52 active ingredients of TW were screened, and 141 predicted targets and 49 target genes related to DN were identified. The biological process of GO is mediated mainly through the regulation of oxygen metabolism, endothelial cell proliferation, acute inflammation, apoptotic signal transduction pathway, fibroblast proliferation, positive regulation of cyclase activity, adipocyte differentiation and other biological processes. KEGG enrichment analysis showed that the main pathways involved were AGE-RAGE, vascular endothelial growth factor, HIF-1, IL-17, relaxin signalling pathway, TNF, Fc epsilon RI, insulin resistance and other signaling pathways. It can be concluded that TW may treat DN by reducing inflammation, reducing antioxidative stress, regulating immunity, improving vascular disease, reducing insulin resistance, delaying renal fibrosis, repairing podocytes, and reducing cell apoptosis, among others, with multicomponent, multitarget and multisystem characteristics.

Parenteral Nutrition and Cardiotoxicity

Parenteral nutrition (PN) is a life-saving nutritional therapy for those situations when patients are unable to receive enteral nutrition. However, despite a multitude of benefits offered by PN, it is associated with a variety of side effects, most notably parenteral nutrition-associated liver disease (PNALD). Adverse effects of PN on other organ systems, such as brain and cardiovascular system, have been poorly studied. There have been several case reports, studies, and a recent animal study highlighting cardiotoxic effects of PN; however, much remains unclear about the underlying mechanisms causing cardiac damage. In this review, we propose a series of potential mechanisms behind PN-associated heart injury, and we provide an overview of therapeutic strategies and recent scientific advances.

Efficacy and Safety of Tripterygium Glycoside in the Treatment of Diabetic Nephropathy: A Systematic Review and Meta-Analysis Based on the Duration of Medication

AIM

The aim of this study was to assess the clinical efficacy and safety of Tripterygium-derived glycosides (TG) after 3-month and 6-month of treatments of diabetic nephropathy (DN) and to resolve the conflict between medicine guidance and clinical practice for TG application.

METHODS

We conducted a systematic review and meta-analysis of randomized controlled trials involving TG application in treating DN. We extensively searched PubMed, Cochrane Library, CNKI, VIP, Wan-Fang, CBM, Chinese Clinical Trial Registry, and WHO International Clinical Trial Registration Platform till November 2020, along with grey literature for diabetes and all other relevant publications to gather eligible studies. Based on the preset inclusion and exclusion criteria, document screening, quality assessment of methodology, and data extraction was conducted by two researchers independently. The methodological quality was assessed by the Cochrane risk test from the Cochrane Handbook 5.2, and then analyses were performed by Review Manager 5.3 (Rev Man 5.3). The quality of output evidence was classified by GRADE.

RESULTS

Thirty-one eligible studies (2764 patients) were included for this meta-analysis. Our study results showed a comparable significant decrease in the 24 h-UTP and blood creatinine levels in DN patients from both 3-month and 6-month TG treatment groups, compared with the routine symptomatic treatment alone. To the contrary of the findings from the included studies, our results showed that the occurrence of serious adverse reaction events was significantly higher in the TG treated group with 6 months of treatment duration compared to that of 3 months of the treatment course. However, the total AR ratio was slightly varied while increasing the percent of severe adverse events. GRADE assessment indicated that the quality of evidence investigating TG-induced adverse reactions was moderate and that for 24 h-UTP and blood creatinine indicators were considerably low.

CONCLUSION

Combinatorial treatment regimen including TG can significantly decrease the pathological indicators for DN progression, while it can also simultaneously predispose the patient to a higher risk for developing severe adverse events, as the medicine guidance indicates. Notably, even in 3-month of course duration smaller percent of severe adverse events can get to a fatal high percent and is likely to increase proportionally as the TG treatment continues. This suggests that TG-mediated DN treatment duration should be optimized to even less than 3 continuous months to avoid adverse event onset-associated further medical complications in DN patients. In clinical practice, serious attention should be paid to these severe side-effects even in a course normally considered safe, and importantly more high-quality studies are urgently warranted to obtain detailed insights into the balance between the efficacy and safety profiles of TG application in treating DN.

Long noncoding RNA Kcnq1ot1 promotes sC5b-9-induced podocyte pyroptosis by inhibiting miR-486a-3p and upregulating NLRP3

Podocytes are epithelial cells adhering glomerular capillaries, which regulate the integrity of glomerular filtration barrier. Irreversible podocyte injury induces glomerular inflammation and causes chronic renal diseases. Kcnq1ot1, a long noncoding RNA, participates in the pathogenesis of diabetic retinopathy and cardiomyopathy. However, its function in podocyte injury is elusive. Pyroptosis of murine podocyte MPC5 was triggered by sublytic complement C5b-9 (sC5b-9) for subsequent in vitro functional and mechanistic investigation. Gain/loss-of-function analysis was conducted to examine the functional role of Kcnq1ot1 in podocyte pyroptosis. Meanwhile, the molecular mechanism of Kcnq1ot1's effect on podocyte injury was explored by identifying downstream molecules and their intermediate interactions. Kcnq1ot1 was upregulated in sC5b-9-induced podocytes, and silencing Kcnq1ot1 could inhibit sC5b-9's effect on podocyte pyroptosis. We also identified the interaction between Kcnq1ot1 and miR-486a-3p, through which Kcnq1ot1 mediated miR-486a-3p inhibition by sC5b-9. Furthermore, miR-486a-3p reduced the transcriptional activity of NLRP3, while the overexpression of NLRP3 enhanced sC5b-9's effect on podocyte pyroptosis through activating NLRP3 inflammasome. sC5b-9 induces pyroptosis in podocytes through modulating the Kcnq1ot1/miR-486a-3p/NLRP3 regulatory axis, and these uncovered key molecules might facilitate podocyte-targeted treatment for renal inflammatory diseases.

Therapeutic Potential of Triptolide as an Anti-Inflammatory Agent in Dextran Sulfate Sodium-Induced Murine Experimental Colitis

Inflammatory bowel disease (IBD), which includes ulcerative colitis (UC) and Crohn’s disease (CD), is a group of chronic and incurable inflammatory diseases involving the gastrointestinal tract. In this study, we investigated the anti-inflammatory effects of triptolide in a dextran sulfate sodium (DSS)-induced mouse colitis model and LPS-activated macrophages and explored the specific molecular mechanism(s). In mice, triptolide treatment showed significant relief and protection against colitis, and it markedly reduced the inflammatory responses of human monocytes and mouse macrophages. Pharmacological analysis and weighted gene co-expression network analysis (WGCNA) suggested that PDE4B may be an important potential targeting molecule for IBD. Exploration of the specific mechanism of action indicated that triptolide reduced the production of ROS, inhibited macrophage infiltration and M1-type polarization by activating the NRF2/HO-1 signaling pathway, and inhibited the PDE4B/AKT/NF-κB signaling cascade, which may help weaken the intestinal inflammatory response. Our findings laid a theoretical foundation for triptolide as a treatment for IBD and revealed PDE4B as a target molecule, thus providing new ideas for the treatment of IBD.

Tripterygium wilfordii Hook F Treatment for Stage IV Diabetic Nephropathy: Protocol for a Prospective, Randomized Controlled Trial

Background

Diabetic nephropathy (DN) is a major cause of chronic kidney disease (CKD). There are no effective treatments to prevent or reverse the progression of DN. A preliminary study showed that Tripterygium glycosides from Tripterygium wilfordii Hook F (TwHF) with valsartan decrease proteinuria in patients with DN.

Objectives

The objective of the present study is to investigate the efficacy and safety of Tripterygium glycosides from TwHF, a traditional Chinese medicine, for the treatment of DN. Methods and Analysis. This is a prospective, single-center randomized controlled trial. Seventy participants diagnosed with DN were recruited and randomized 1 : 1 to two groups: (1) angiotensin receptor blocker (ARB) combined with TwHF and (2) ARB-only. The treatment period is 48 weeks. The primary endpoint is 24 h proteinuria decreased level (reduction of 30% vs. baseline) after 48 weeks of treatment. The secondary endpoints are (1) all-cause and cardiovascular-related mortality, (2) development of ESRD (serum creatinine > 530.4 μmol/L or estimated glomerular filtration rate (eGFR) < 15 mL/min/1.73 m²), (3) the need for renal replacement therapy, and (4) increased serum creatinine (2-fold higher than the baseline value or ≥442 μmol/L, with confirmation of the initial results after 4 weeks). A health economics analysis will be carried out. Discussion. A meta-analysis of RCTs carried out in patients with stage 4 (Mogensen classification) diabetic CKD showed that TwHF combined with an ARB was more effective than an ARB alone when considering 24 h proteinuria and serum albumin, but with an increase in adverse event (AE) frequency of 8%. This is a prospective clinical trial that may provide information on a safe and effective novel method for the treatment of DN, especially for patients with macroproteinuria. Ethics and Dissemination. The protocol is approved by the ethics committee of Beijing Hospital (2016BJYYEC-059-02). The results will be disseminated through peer-reviewed publications and international conferences. This trial is registered with ChiCTR-IOR-17010623.

Triptolide ameliorates fine particulate matter-induced podocytes injury via regulating NF-κB signaling pathway

BACKGROUND

PM2.5 is associated closely with an increased risk of membranous nephropathy (MN), however, whether PM2.5 could induce podocytes injury, the underlying pathology for MN, has not be thoroughly studied. Triptolide, an active component in Tripterygium wilfordii Hook F, is frequently used to treat MN in China, but its effects on PM2.5-induced podocytes injury is still largely unknown. Therefore, we evaluated the effects of PM2.5 on podocytes, and explored whether triptolide could improve PM2.5-induced podocytes injury and the possible underlying mechanisms.

RESULTS

Podocytes were incubated with PM2.5 after being pre-treated with triptolide, viability, apoptosis rate and migratory capacity of podocytes were determined by CCK-8 assay, flow cytometry and Transwell assay, respectively. Additionally, the levels of lactate dehydrogenase (LDH), malondialdehyde (MDA), and superoxide dismutase (SOD) in podocytes, the cytoskeleton of podocytes, the protein expressions of nephrin, podocin, Bcl-2, Bax, nuclear factor kappa-B/p65 (NF-κB/p65) and phospho-inhibitor of NF-κB (p-IκBα) were measured. Our data showed that PM2.5 treatment significantly increased the disorganization of F-actin stress fibers, the damaged structural integrity of nucleus, the deranged and dissociated cytoskeleton in podocytes, increased the podocytes apoptosis rate, the levels of MDA and LDH, markedly up-regulated the protein expression of Bax, NF-κB/p65 and p-IκBα, down-regulated the protein expression of nephrin, podocin and Bcl-2, and significantly decreased the level of SOD, the migration rate and the viability of podocytes, compared with those of the untreated podocytes. These effects of PM2.5 on podocytes, however, were reversed by triptolide administration.

CONCLUSION

These results suggest that triptolide could prevent against PM2.5-induced podocytes injury via suppressing NF-κB signaling pathway.

Protosappanin-A and oleanolic acid protect injured podocytes from apoptosis through inhibition of AKT-mTOR signaling

Protosappanin-A (PrA) and oleanolic acid (OA), which are important effective ingredients isolated from Caesalpinia sappan L., exhibit therapeutic potential in multiple diseases. This study focused on exploring the mechanisms of PrA and OA function in podocyte injury. An in vitro model of podocyte injury was induced by the sC5b-9 complex and assays such as cell viability, apoptosis, immunofluorescence, quantitative real-time polymerase chain reaction, and western blot were performed to further investigate the effects and mechanisms of PrA and OA in podocyte injury. The models of podocyte injury were verified to be successful as seen through significantly decreased levels of nephrin, podocin, and CD2AP and increased level of desmin. The sC5b-9-induced podocyte apoptosis was inhibited in injured podocytes treated with PrA and OA, accompanied by increased protein levels of nephrin, podocin, CD2AP, and Bcl2 and decreased levels of desmin and Bax. The p-AKT/p-mTOR levels were also reduced by treatment of PrA and OA while AKT/mTOR was unaltered. Further, the effects of PrA and OA on injured podocytes were similar to that of LY294002 (a PI3K-AKT inhibitor). PrA and OA were also seen to inhibit podocyte apoptosis and p-AKT/p-mTOR levels induced by IGF-1 (a PI3K-AKT activator). Our data demonstrate that PrA and OA can protect podocytes from injury or apoptosis, which may occur through inhibition of the abnormal activation of AKT-mTOR signaling.

Application and Mechanisms of Triptolide in the Treatment of Inflammatory Diseases-A Review

Bioactive compounds from medicinal plants with anti-inflammatory and immunosuppressive effects have been emerging as important sources of drugs for the treatment of inflammatory disorders. Triptolide, a diterpene triepoxide, is a pharmacologically active compound isolated from Tripterygium wilfordii Hook F (TwHF) that is used as a remedy for inflammatory and autoimmune diseases. As the most promising bioactive compound obtained from TwHF, triptolide has attracted considerable interest recently, especially for its potent anti-inflammatory and immunosuppressive activities. Over the past few years, an increasing number of studies have been published emphasizing the value of triptolide in the treatment of diverse inflammatory disorders. Here, we systematically review the mechanism of action and the therapeutic properties of triptolide in various inflammatory diseases according to different systematic organs, including lupus nephritis, inflammatory bowel disease, asthma, and rheumatoid arthritis with pubmed and Embase. Based on this review, potential research strategies might contribute to the clinical application of triptolide in the future.

Comparative efficacy of 13 immunosuppressive agents for idiopathic membranous nephropathy in adults with nephrotic syndrome: a systematic review and network meta-analysis

OBJECTIVES

This study aimed to compare the effectiveness of 13 types of immunosuppressive agents used to treat idiopathic membranous nephropathy (IMN) in adults with nephrotic syndrome.

DESIGN

Systematic review and network meta-analysis.

DATA SOURCES

PubMed, EMbase, Cochrane Library, Web of Science, Clinical trials, SinoMed, Chinese Biomedicine, CNKI, WanFang and Chongqing VIP Information databases were comprehensively searched until February 2018.

ELIGIBILITY CRITERIA

Randomised clinical trials (RCTs) comparing the effects of different immunosuppressive treatments in adult patients with IMN and nephrotic syndrome were included, and all included RCTs had a study-duration of at least 6 months.

DATA EXTRACTION AND SYNTHESIS

Two reviewers independently screened articles, extracted data and assessed study quality. Standard pairwise meta-analysis was performed using DerSimonian-Laird random-effects model.

RESULTS

This study ultimately included 48 RCTs with 2736 patients and 13 immunosuppressive agents. The network meta-analysis results showed that most regimens, except for leflunomide (LEF), mizoribine (MZB) and steroids (STE), showed significantly higher probabilities of total remission (TR) when compared with non-immunosuppressive therapies (the control group),with risk ratios (RRs) of 2.71 (95% CI) 1.81 to 4.06)for tacrolimus+tripterygium wilfordii (TAC+TW), 2.16 (1.27 to 3.69) foradrenocorticotropic hormone, 2.02 (1.64 to 2.49) for TAC, 2.03 (1.13 to3.64) for azathioprine (AZA), 1.91 (1.46 to 2.50) for cyclosporine (CsA), 1.86 (1.44 to2.42) for mycophenolate mofetil (MMF), 1.85 (1.52 to 2.25) for cyclophosphamide (CTX),1.81 (1.10 to 2.98) for rituximab (RIT), 1.80 (1.38 to 2.33) for TW, 1.72 (1.35 to 2.19) for chlorambucil. As for 24 hours UTP, the direct andindirect comparisons showed that AZA (standard mean difference (SMD), -1.02(95% CI -1.90 to -0.15)), CsA (SMD, -0.70 (95% CI -1.33 to -0.08)),CTX (SMD, -1.01 (95% CI -1.44 to -0.58)), MMF (SMD, -0.98 (95% CI -1.64 to -0.32)), MZB (SMD, -0.97 (95% CI -1.90 to-0.04]), TAC (SMD, -1.16 (95% CI -1.72 to -0.60)) and TAC+TW(SMD, -2.03 (95% CI -2.94 to -1.12)) could significantly superior thancontrol, except for chlorambucil, LEF, RIT and STE. Thechanges of serum creatinine (Scr) was not significantly different between eachtreatments of immunosuppressive agents and the control, except for STE whichhas the possibility of increasing Scr (SMD, 1.00 (95% CI 0.36 to 1.64)).Comparisons among all treatments of immunosuppressive agents showed nostatistical significance in the outcome of relapse. A drenocorticotropichormone (85.1%) showed the lowest probability of relapse under the cumulativeranking curve values among all immunosuppressants. Infection,gastrointestinal symptoms, and bone marrow suppression were the common adverseevents associated with most of the immunosuppressive therapies.

CONCLUSIONS

This study demonstrates that TAC+TW, TAC and CTX are superior to other immunosuppressive agents in terms of TR and 24 hours UTP. Moreover, they are all at risk of infection, gastrointestinal symptoms, and myelosuppression. Furthermore, TAC could increase the risk of glucose intolerance or new-onset diabetes mellitus. Conversely, STE alone, LEF and MZB seem to have little advantage in clinical treatment of IMN.

PROSPERO REGISTRATION NUMBER

CRD42018094228.

Differential toxicities of triptolide to immortalized podocytes and the podocytes in vivo

Triptolide (TP) has an anti-proteinuric effect and is used for the treatment of podocytopathies. TP has also been shown to act directly on immortalized podocytes in culture to protect them from injury. In the present study, we examined the effect of TP on healthy podocytes both in vitro and in vivo to better understand the action of TP on podocytes. We found that treatment of TP at 10 ng/ml, a concentration that is routinely used for podocyte protection, was sufficient to activate pro-apoptotic signaling of MAPK p38, p53 and BAX and induced apoptosis in cultured podocytes; and higher concentrations of TP exacerbated the p38, p53 and BAX activations and apoptosis. Moreover, TP severely downregulated the genes that are essential for podocyte structure and function. Interestingly, in contrast with other agents TP-induced podocyte injury was not prevented by glucocorticoids. In vivo, high-dose TP treatment for prolonged time did not cause podocyte injury, essential genes downregulation, and proteinuria in mice. TP was also not toxic to the podocytes with isolated glomeruli ex vivo. In summary, TP is toxic to immortalized podocytes in culture but not to the podocytes in animals or isolated glomeruli ex vivo. Our study suggests that immortalized podocytes might have genetically evolved to become sensitive to TP toxicity and thus caution should be taken in interpreting data from immortalized podocytes. Nevertheless, in vivo TP could be as safe as glucocorticoids in treating podocytopathies. Finally, TP may be used as a unique in vitro model for studying steroid-resistant podocytopathies.

Triptolide delays disease progression in an adult rat model of polycystic kidney disease through the JAK2-STAT3 pathway

The aim of our current study was to investigate the long-term effect and the mechanism of triptolide in an adult nonorthologous rat model of polycystic kidney disease (PKD). Male wild-type (+/+) and Cy/+ cystic Han:SPRD rats were treated with vehicle or triptolide from 4 to 16 wk of age. Rats were killed at 16 wk of age for blood, urine, and organ collection. Human-derived WT9–12 PKD cells were treated with triptolide with or without IL-6 pretreatment. Cell proliferation, apoptosis, and cytotoxicity were determined. Western blotting and immunohistochemistry analysis were performed to evaluate the activation of IL-6-JAK2-STAT3 pathway. Renal function was protected by 12 wk of triptolide treatment in cystic Han:SPRD rats as shown by reduced blood urea nitrogen, serum creatinine, and proteinuria levels. Cyst and kidney growth were also retarded by triptolide treatment in Cy/+ rats. We further found that the proliferation index was reduced by triptolide in cystic rats, which was correlated with the reduced expression of IL-6/IL-6 receptor, decreased phosphorylation of JAK2-STAT3, and increased expression of suppressor of cytokine signaling 3 (SOCS3). The inhibitory effect of triptolide was further studied in WT9–12 cells. Triptolide inhibited cell proliferation and the activation of JAK2-STAT3 pathway in PKD cells, but it increased the expression of SOCS3. Pretreatment with IL-6 attenuated the inhibitory effect of triptolide on STAT3 phosphorylation. Our study revealed a long-term beneficial effect of triptolide in PKD that was probably through inhibition of the JAK2-STAT3 pathway.

Biomarker prediction for membranous nephropathy prognosis by microarray analysis

AIM

This study aimed to explore biomarkers for membranous nephropathy (MN) diagnosis and to provide novel insights into the pathogenesis of this disease.

METHODS

A microarray data set, GSE73953, was used, which contained 15 immunoglobulin A nephropathy (IgAN) samples, 8 MN samples and 2 healthy controls. Pretreatments were performed for the raw data, and then, the differentially expressed genes (DEG) were screened out using the limma package. The function and pathways of these genes were demonstrated through enrichment analysis. Protein-protein interaction (PPI) network analysis was performed to uncover interactions of DEG from the protein level. MN-related genes were further selected, integrating the Comparative Toxicogenomics Database (CTD).

RESULTS

In total, 446 and 231 DEG were identified in the comparisons of MN versus control and MN versus IgAN, respectively. JUN, NFKB1, TGFB1 and PPBP were the predominant DEG, and the latter two were especially differentially expressed between the MN and IgAN groups. UBL4A and EIF4G1 were the two most important DEG for MN because they were downregulated compared with both control and IgAN groups. The above-mentioned genes were highlighted in the PPI networks and mainly enriched the ribosome- and platelet-related function/pathways.

CONCLUSION

Several potential biomarkers were identified in MN, and some of them could well distinguish the MN from IgAN. Disruption of ribosome- and platelet-related function or pathways might contribute to MN progression. EIF4F and UBL4A might be two novel biomarkers for MN prognosis. Nevertheless, more experimental validations are needed.

Retrospective analysis of tacrolimus combined with Tripterygium wilfordii polyglycoside for treating idiopathic membranous nephropathy

BACKGROUND

Idiopathic membranous nephropathy (IMN) is one of the most common adult nephrotic syndromes. Some patients with this disorder require immunosuppressive therapy. This retrospective case series was performed to assess the effects of tacrolimus (TAC) combined with Tripterygium wilfordii polyglycoside (TWG) in treating IMN.

METHODS

From January 2015 to August 2016, kidney-biopsy-proven IMN patients treated with TAC in the Chinese PLA General Hospital were screened. Data were retrieved from the patients' medical records. The first efficacy evaluation index was remission rate (complete remission and partial remission), and the secondary efficacy evaluation indices included relapse rate, proteinuria, serum albumin and estimated glomerular filtration rate (eGFR). Adverse events were also assessed.

RESULTS

The included patients' treatments were tacrolimus monotherapy (TAC group, n = 33), tacrolimus combined with methylprednisolone (MP) (TAC + MP group, n = 24) and tacrolimus combined with Tripterygium wilfordii polyglycoside (TAC + TWG group, n = 21). The remission rates of the TAC, TAC + MP, and TAC + TWG groups in the 10th month were 54.5, 62.5, and 85.7%, respectively (TAC + TWG group vs TAC group, P = 0.037, TAC + TWG group vs TAC + MP group, P = 0.125). Moreover, the complete remission rates of the TAC, TAC + MP, and TAC + TWG groups in the 10th month were 21.2, 20.8, and 57.1%, respectively (TAC + TWG group vs TAC group, P = 0.007, TAC + TWG group vs TAC + MP group, P = 0.012). Compared with the TAC group, the TAC + TWG group had a higher remission rate during these ten months (log-rank, P = 0.005). Compared with the TAC and TAC + MP groups, the TAC + TWG group had a higher complete remission rate (log-rank, P = 0.019 and log-rank, P = 0.005, respectively).

CONCLUSION

This retrospective study showed that TAC combined with TWG may be effective for treating IMN. Further randomized controlled trials (RCTs) are needed to assess the efficacy and safety of TAC combined with TWG.

Triptolide attenuates proteinuria and podocyte apoptosis via inhibition of NF-κB/GADD45B

Podocyte injury is a primary contributor to proteinuria. Triptolide is a major active component of Tripterygium wilfordii Hook F that exhibits potent antiproteinuric effects. We used our previously developed in vivo zebrafish model of inducible podocyte-target injury and found that triptolide treatment effectively alleviated oedema, proteinuria and foot process effacement. Triptolide also inhibited podocyte apoptosis in our zebrafish model and in vitro. We also examined the mechanism of triptolide protection of podocyte. Whole-genome expression profiles of cultured podocytes demonstrated that triptolide treatment downregulated apoptosis pathway-related GADD45B expression. Specific overexpression of gadd45b in zebrafish podocytes abolished the protective effects of triptolide. GADD45B is a mediator of podocyte apoptosis that contains typical NF-κB binding sites in the promoter region, and NF-κB p65 primarily transactivates this gene. Triptolide inhibited NF-κB signalling activation and binding of NF-κB to the GADD45B promoter. Taken together, our findings demonstrated that triptolide attenuated proteinuria and podocyte apoptosis via inhibition of NF-κB/GADD45B signalling, which provides a new understanding of the antiproteinuric effects of triptolide in glomerular diseases.

Tripterygium glycoside protects against puromycin amino nucleoside‑induced podocyte injury by upregulating autophagy

Tripterygium glycoside (TG), an active ingredient of the widely used Chinese herb Tripterygium wilfordii Hook F, has immunosuppressive and anti-inflammatory effects. Previous studies have indicated that TG is a potentially effective therapeutic option to treat nephrotic syndrome. The mechanism underlying the therapeutic effect of TG, including its effect on autophagy and apoptosis in podocyte injury, remains to be fully elucidated. The present study aimed to assess the protective effect of TG on podocytes via its potential role in the activation of autophagic and phosphatidylinositol 3-kinase (PI3K) pathways. Using flow cytometry, western blot analysis, cell counting kit-8 assays and transmission electron microscopy analysis, the effects of TG on puromycin amino-nucleoside (PAN)-induced podocyte injury were investigated. Chloroquine (CQ), an inhibitor of autophagy, was used to assess the importance of autophagy in the protective effect of TG. In addition, LY294002, an inhibitor of class III PI3K, was used to identify which signaling pathways TG is involved in. PAN caused marked apoptosis of podocytes, which was significantly antagonized by TG. The expression of microtubule-associated protein 1A/1B-light chain 3 and the appearance of autophagosomes increased significantly following TG treatment, whereas the expression levels of p62 and cleaved caspase-3 were markedly decreased. Podocyte apoptosis decreased significantly when the podocytes were treated with TG compared with the levels of apoptosis in the PAN- and PAN+CQ-treated groups. The expression of phosphorylated AKT was increased significantly in the TG-treated groups, and the effects of TG on the podocytes were significantly inhibited by LY294002. In conclusion, TG protected podocytes from PAN-induced injury, and the effects were attributable to the activation of autophagy, mainly via a PI3K-dependent pathway.

Cellular death, reactive oxygen species (ROS) and diabetic complications

Chronic or intermittent hyperglycemia is associated with the development of diabetic complications. Several signaling pathways can be altered by having hyperglycemia in different tissues, producing oxidative stress, the formation of advanced glycation end products (AGEs), as well as the secretion of the pro-inflammatory cytokines and cellular death (pathological autophagy and/or apoptosis). However, the signaling pathways that are directly triggered by hyperglycemia appear to have a pivotal role in diabetic complications due to the production of reactive oxygen species (ROS), oxidative stress, and cellular death. The present review will discuss the role of cellular death in diabetic complications, and it will suggest the cause and the consequences between the hyperglycemia-induced signaling pathways and cell death. The signaling pathways discussed in this review are to be described step-by-step, together with their respective inhibitors. They involve diacylglycerol, the activation of protein kinase C (PKC) and NADPH-oxidase system, and the consequent production of ROS. This was initially entitled the “dangerous metabolic route in diabetes”. The historical usages and the recent advancement of new drugs in controlling possible therapeutical targets have been highlighted, in order to evaluate the evolution of knowledge in this sensitive area. It has recently been shown that the metabolic responses to stimuli (i.e., hyperglycemia) involve an integrated network of signaling pathways, in order to define the exact responses. Certain new drugs have been experimentally tested—or suggested and proposed—for their ability to modulate the possible biochemical therapeutical targets for the downregulation of retinopathy, nephropathy, neuropathy, heart disease, angiogenesis, oxidative stress, and cellular death. The aim of this study was to critically and didactically evaluate the exact steps of these signaling pathways and hence mark the indicated sites for the actions of such drugs and their possible consequences. This review will emphasize, besides others, the therapeutical targets for controlling the signaling pathways, when aimed at the downregulation of ROS generation, oxidative stress, and, consequently, cellular death—with all of these conditions being a problem in diabetes.