Triptolide is a potent suppressant of C3, CD40 and B7h expression in activated human proximal tubular epithelial cells

Natural products applied in acute kidney injury treatment: polymer matters

Acute kidney injury (AKI) is a global health threat due to its high morbidity and mortality. There is still a lack of effective therapeutic methods to deal with AKI clinically. Natural products with outstanding accessibility and bioactivity are potential candidates for AKI treatment. Natural product-based prodrugs or nano-structures with improved properties are frequently fabricated for maximizing bioavailability and decreasing side effects, in which natural polymers are selected as carriers, or natural drugs are loaded as cargos on designed polymers. In this review, the etiologies of AKI are briefly presented, and emerging natural products delivered rationally for AKI therapy, as either carriers or cargos, are both introduced. Moreover, the challenges of the future development of nature-based nanodrugs or prodrugs for AKI have also been discussed.

A Review of the Potential Benefits of Herbal Medicines, Small Molecules of Natural Sources, and Supplements for Health Promotion in Lupus Conditions

The Latin word lupus, meaning wolf, was in the medical literature prior to the 1200s to describe skin lesions that devour flesh, and the resources available to physicians to help people were limited. The present text reviews the ethnobotanical and pharmacological aspects of medicinal plants and purified molecules from natural sources with efficacy against lupus conditions. Among these molecules are artemisinin and its derivatives, antroquinonol, baicalin, curcumin, emodin, mangiferin, salvianolic acid A, triptolide, the total glycosides of paeony (TGP), and other supplements such as fatty acids and vitamins. In addition, medicinal plants, herbal remedies, mushrooms, and fungi that have been investigated for their effects on different lupus conditions through clinical trials, in vivo, in vitro, or in silico studies are reviewed. A special emphasis was placed on clinical trials, active phytochemicals, and their mechanisms of action. This review can be helpful for researchers in designing new goal-oriented studies. It can also help practitioners gain insight into recent updates on supplements that might help patients suffering from lupus conditions.

The Negative Impact of Triptolide on the Immune Function of Human Natural Killer Cells

Triptolide (TP), a bioactive compound extracted the from traditional Chinese medicine Tripterygium wilfordii Hook F (TwHF), has been shown to be effective in treating several autoimmune diseases, and has suppressive effects in several key immune cells such as dendritic cells, T cells, and macrophages. However, it is unknown whether TP has an impact on natural killer (NK) cells. Here, we report that TP has suppressive effects on human NK cell activity and effector functions. The suppressive effects were observed in human peripheral blood mononuclear cell cultures and purified NK cells from healthy donors, as well as in purified NK cells from patients with rheumatoid arthritis. TP treatment induced downregulation of NK-activating receptor (CD54, CD69) expression and IFN-gamma secretion, in a dose-dependent manner. When exposed to K562 target cells, TP treatment induced inhibition of surface expression of CD107a and IFN-gamma synthesis in NK cells. Furthermore, TP treatment induced activation of inhibitory signaling (SHIP, JNK) and inhibition of MAPK signaling (p38). Thus, our findings demonstrate a previously unknown role for TP in NK cell functional suppression and reveal several key intracellular signaling that can be regulated by TP. Our findings also offer new insight into mechanisms of TP therapeutic treatment in autoimmune disease.

Applications and Mechanisms of Tripterygium Wilfordii Hook. F. and its Preparations in Kidney Diseases

Tripterygium wilfordii Hook. f. (TwHF) is a Chinese botanical drug containing a large number of metabolites. The discovered and recognized anti-inflammatory and immune-regulating effects have made it attract more and more attentions in trials and clinical researches. The extraction and processing of TwHF for pharmaceuticals is a manifestation of the role of traditional Chinese medicine. However, TwHF is toxic. Optimization of TwHF preparations has become a requirement for the development of TwHF pharmaceuticals. Our article introduces the main preparations of TwHF on the Chinese market and their characteristics. In particular, we summarize the clinical applications and influential mechanisms of TwHF and its preparations in kidney diseases. Considering that nephropathy is closely related to immune inflammation and TwHF is a botanical drug with a high number of metabolites, the application of TwHF in kidney diseases may be much more complicated. By revealing the role and mechanisms of TwHF in kidney diseases, this study aims to provide more insights to basic and clinical studies about nephropathy.

Based on Network Pharmacology Tools to Investigate the Mechanism of Tripterygium wilfordii Against IgA Nephropathy

Background: Immunoglobulin A nephropathy (IgAN) is the most common primary glomerular disease and poses a global major public health burden. The preparation of Tripterygium wilfordii Hook F (TwHF) is widely applied for treating patients with Immunoglobulin A nephropathy in China, while the molecular mechanisms remain unclear. This study aimed to verify the therapeutic mechanism of TwHF on IgAN by undertaking a holistic network pharmacology strategy in combination with in vitro and in vivo experiments.

Methods: TwHF active ingredients and their targets were obtained via the Traditional Chinese Medicine Systems Pharmacology Database. The collection of IgAN-related target genes was collected from GeneCards and OMIM. TwHF-IgAN common targets were integrated and visualized by Cytoscape. Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses were performed to determine the predominant molecular mechanisms and pathways of TwHF on the treatment of IgAN. The protein-protein interaction network was constructed by the STRING online search tool, and hub genes were identified using R software. The expression of hub gene and related signaling were evaluated in TwHF-treated mice through immunohistochemistry and western blot and further validated in human mesangial cells (HMCs). In addition, Cell counting kit 8 (CCK8) and flow cytometry were used to detect the effects of TwHF on cell proliferation and cell cycle of mesangial cells.

Results: A total of 51 active ingredients were screened from TwHF and 61 overlapping targets related to IgAN were considered potential therapeutic targets, GO functions and KEGG analyses demonstrated that these genes were primarily associated with DNA-binding transcription factor binding, lipid and atherosclerosis pathway. Genes with higher degrees including AKT1, CXCL8, MMP9, PTGS2, CASP3, JUN are hub genes of TwHF against IgAN. Verification of hub gene JUN both in vitro and in vivo showed that TwHF significantly attenuated JUN phosphorylation in the kidneys of IgAN mice and aIgA1-activated HMCs, meanwhile suppressing HMCs proliferation and arresting G1-S cell cycle progression.

Conclusion: Our research strengthened the mechanisms of TwHF in treating IgAN, inhibition of JUN activation may play a pivotal role in TwHF in alleviating IgAN renal injury.

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.

Triptolide: pharmacological spectrum, biosynthesis, chemical synthesis and derivatives

Triptolide, an abietane-type diterpenoid isolated from Tripterygium wilfordii Hook. F., has significant pharmacological activity. Research results show that triptolide has obvious inhibitory effects on many solid tumors. Therefore, triptolide has become one of the lead compounds candidates for being the next "blockbuster" drug, and multiple triptolide derivatives have entered clinical research. An increasing number of researchers have developed triptolide synthesis methods to meet the clinical need. To provide new ideas for researchers in different disciplines and connect different disciplines with researchers aiming to solve scientific problems more efficiently, this article reviews the research progress made with analyzes of triptolide pharmacological activity, biosynthetic pathways, and chemical synthesis pathways and reported in toxicological and clinical studies of derivatives over the past 20 years, which have laid the foundation for subsequent researchers to study triptolide in many ways.

Role of chemokines, innate and adaptive immunity

Polycystic Kidney Disease (PKD) triggers a robust immune system response including changes in both innate and adaptive immunity. These changes involve immune cells (e.g., macrophages and T cells) as well as cytokines and chemokines (e.g., MCP-1) that regulate the production, differentiation, homing, and various functions of these cells. This review is focused on the role of the immune system and its associated factors in the pathogenesis of PKDs as evidenced by data from cell-based systems, animal models, and PKD patients. It also highlights relevant pre-clinical and clinical studies that point to specific immune system components as promising candidates for the development of prognostic biomarkers and therapeutic strategies to improve PKD outcomes.

Use of Tripterygium wilfordii Hook F for immune-mediated inflammatory diseases: progress and future prospects

Tripterygium wilfordii Hook F has significant anti-inflammatory and immunosuppressive properties and is widely used for treating autoimmune and inflammatory diseases such as rheumatoid arthritis, systemic lupus erythematosus, and kidney disease, especially in traditional Chinese medicine. The mechanisms underlying its effects may be diverse but they remain unclear, and its toxicity and side effects limit its wider clinical application. This review summarizes the clinical application of Tripterygium wilfordii Hook F in recent years, as well as the results of studies into its mechanisms and toxicity, to provide a reference for its future clinical application.

The role of hypertriglyceridemia and treatment patterns in the progression of IgA nephropathy with a high proportion of global glomerulosclerosis

PURPOSE

Many studies have focused on finding predictors for mild IgAN progression. However, the cases of severe IgAN with a high proportion of global glomerulosclerosis have received inadequate attention.

METHODS

A group of 172 primary IgAN patients with 50-75% global glomerulosclerosis was studied retrospectively between April 2007 and October 2017. Patients were divided into three groups according to the serum triglyceride tertiles:  < 1.42 µmol/L (Group 1), 1.42-2.29 µmol/L (Group 2), and > 2.29 µmol/L (Group 3). Groups 1 and 2 comprised non-hypertriglyceridemia subjects, while Group 3 was defined as the hypertriglyceridemia (HTG) group. The patients were followed for 4-96 months (median 39.43 months). The study end point was defined as a 50% decline in estimated glomerular filtration rate (eGFR) or ESRD.

RESULTS

A high proportion of global glomerulosclerosis is not absolutely correlated with severe clinical features and poor renal outcome. In our retrospective observation, eGFR decreased by less than 10% of the baseline during follow-up in 43.6% of the patients. However, in our patients with HTG, the cumulative renal survival rate was significantly lower compared to those without HTG. Multivariate Cox regression analysis also showed that triglyceride is an independent predictor of poor renal outcomes. Furthermore, in the HTG group, the cumulative renal survival rates were higher in patients treated with Tripterygium wilfordii Hook F (TwHF) compared to those without TwHF.

CONCLUSIONS

A high proportion of global glomerulosclerosis combined with HTG at biopsy have better predictive validity for the disease progression of IgAN than global glomerulosclerosis alone. TwHF may partially affect the renal outcome of severe IgAN with HTG, and this may relate to its regulation of lipid metabolism and immunoinflammatory response.

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.

Triptriolide antagonizes triptolide-induced nephrocyte apoptosis via inhibiting oxidative stress in vitro and in vivo

Triptolide(T9) is a predominant bioactive component extracted from Chinese herb Tripterygium wilfordii Hook F. (TwHF), and has multiple pharmacological activities, such as immunosuppressive and anti-inflammatory activities, et al. However, severe adverse effects and toxicity, particularly nephrotoxicity, limit its clinical application. It has been demonstrated that the activation of nuclear factor erythroid 2-related factor 2 (Nrf2) signaling pathway could alleviate T9-induced nephrocyte damage. The aim of this study was to investigate the potential protective role of triptriolide (T11) against T9-induced nephrocyte apoptosis in vitro and in vivo. Renal injury models were established in human kidney 2 (HK2) cells and BALB/c mice using T9, and the protective effects of T11 were probed in vitro and in vivo, respectively. T9 induced nephrocyte damage in HK2 cells and BALB/c mice by induction of reactive oxygen species (ROS), lactate dehydrogenase (LDH), malondialdehyde (MDA) and glutathione (GSH) and reduction of superoxide dismutase (SOD), which resulted in the apoptosis of nephrocyte and injury of renal function. While, pretreatment of T11 effectively reversed these changes, resulting in the obvious decrease of oxidative stress and renal function parameters, ameliorated nephrocyte apoptosis, improved cell morphology, and higher increase of Nrf2, NAD(P)H: quinine oxidoreductase 1 (NQO1) and heme oxygenase 1 (HO-1) protein levels in vitro and in vivo. Altogether, T11 protected against T9-induced nephrocyte apoptosis possibly via suppressing oxidative stress.

Kidney-targeted triptolide-encapsulated mesoscale nanoparticles for high-efficiency treatment of kidney injury

Insolubility and toxicity of TP restrict clinical applications in renal diseases. Here, TP-encapsulated mesoscale nanoparticles offer a new therapeutic strategy for renal diseases due to good biocompability, kidney targeting and slow release.

Emerging therapeutic strategies for minimal change disease and focal and segmental glomerulosclerosis

INTRODUCTION

Minimal change disease (MCD) and Focal and segmental glomerulosclerosis (FSGS) are two of the major causes of nephrotic syndrome (NS) in children and adults. According to KDIGO (Kidney Disease: Improving Global Outcomes) guidelines, the treatment of adult primary MCD and FSGS should be based on immunosuppressants and antiproteinuric drugs. Recently, Rituximab, a humanized monoclonal antibody (mAb) has emerged as a potential treatment for steroid or calcineurin inhibitor-dependent patients; it has however demonstrated lower efficacy in those with nephrotic syndrome that is resistant to the above indicated drugs.

AREAS COVERED

Analysis of ongoing and already completed clinical trials, retrieved from clinicaltrials.gov, clinicaltrialsregister.eu and PubMed involving new therapies for nephrotic syndrome secondary to MCD and FSGS.

EXPERT OPINION

The most promising drugs under investigation for MCD and FSGS are mAbs. We are hopeful that new therapeutic options to treat multi-drug resistant MCD and FSGS will emerge from currently ongoing studies. What appears certain is the difficulty in enrolling patients affected by orphan renal diseases and the selection of valid endpoints in clinical trials, such as kidney failure.

A PRISMA-compliant systematic review and network meta-analysis on the efficacy between different regimens based on Tripterygium wilfordii Hook F in patients with primary nephrotic syndrome

BACKGROUND

The present study aims to comprehensively determine the efficacy of different therapy regimens based on Tripterygium wilfordii Hook F (TwHF) for patients with primary nephrotic syndrome (PNS) using network meta-analysis method.

METHODS

Seven electronic databases were searched to identify randomized controlled trials (RCTs) that compared the differences between different therapy regimens based on TwHF for patients with PNS. The risk of bias in included RCTs was evaluated according to the Cochrane Handbook version 5.2.0. Network meta-analysis was performed to compare different regimens. Primary outcomes were complete remission rate and total remission rate. The secondary outcomes were hr urinary protein excretion, serum albumin, serum creatinine, and urea nitrogen. Data analysis was performed using R software.

RESULTS

A total of 40 studies involving 2846 patients with PNS were included. Compared with prednisone, the improvement in total remission rate and complete remission rate was associated with TwHF alone (odds ratio [OR] = 4.80, 95% credible intervals [CrI]: 2.20-10.00; OR = 6.30, 95% CrI: 2.90-13.00, respectively), TwHF+prednisone (OR = 2.10, 95% CrI: 1.30-3.50; OR = 2.40, 95% CrI: 1.50-3.80, respectively), TwHF+CPA (OR = 12.00, 95% CrI: 1.10-150.00; OR = 16.00, 95% CrI: 1.60-170.00, respectively), and TwHF+Cyclosporine A (OR = 28.00, 95% CrI: 3.20-250.00; OR = 35.00, 95% CrI: 4.50-270.00, respectively). Compared with TwHF alone, TwHF+prednisone showed less benefit in improving total remission rate and complete remission rate (OR = 0.44, 95% CrI: 0.21-0.91; OR = 0.38, 95% CrI: 0.19-0.77, respectively). TwHF alone, TwHF+prednisone could significantly reduce hr urinary protein excretion (MD = -0.69, 95% CrI: -1.30 to -0.14; MD = -1.00, 95% CrI: -1.90 to -0.14, respectively) and increase serum albumin (MD = 5.90, 95% CrI: 2.50-9.30; MD = 3.40, 95% CrI: 1.30-5.50, respectively) when compared to prednisone alone. TwHF alone showed significant reduction in serum creatinine when compared to CPA (MD = -19.00, 95% CrI: -37.00 to -0.56).

CONCLUSIONS

TwHF alone, the addition TwHF to prednisone showed more benefit in improving total and complete remission rate, hr urinary protein excretion, serum albumin, and serum creatinine.

Epithelial C5aR1 Signaling Enhances Uropathogenic Escherichia coli Adhesion to Human Renal Tubular Epithelial Cells

Recent work in a murine model of ascending urinary tract infection has suggested that C5a/C5aR1 interactions play a pathogenic role in the development of renal infection through enhancement of bacterial adhesion/colonization to renal tubular epithelial cells (RTECs). In the present study, we extended these observations to human. We show that renal tubular epithelial C5aR1 signaling is involved in promoting uropathogenic Escherichia coli (UPEC) adhesion/invasion of host cells. Stimulation of primary cultures of RTEC with C5a resulted in significant increases in UPEC adhesion/invasion of the RTEC. This was associated with enhanced expression of terminal α-mannosyl residues (Man) (a ligand for type 1 fimbriae of E. coli) in the RTEC following C5a stimulation. Mechanism studies revealed that C5aR1-mediated activation of ERK1/2/NF-κB and upregulation of proinflammatory cytokine production (i.e., TNF-α) is at least partly responsible for the upregulation of Man expression and bacterial adhesion. Clinical sample studies showed that C5aR1 and Man were clearly detected in the renal tubular epithelium of normal human kidney biopsies, and UPEC bound to the epithelium in a d-mannose-dependent manner. Additionally, C5a levels were significantly increased in urine of urinary tract infection patients compared with healthy controls. Our data therefore demonstrate that, in agreement with observations in mice, human renal tubular epithelial C5aR1 signaling can upregulate Man expression in RTEC, which enhances UPEC adhesion to and invasion of RTEC. It also suggests the in vivo relevance of upregulation of Man expression in renal tubular epithelium by C5a/C5aR1 interactions and its potential impact on renal infection.

Triptolide inhibits donor-specific antibody production and attenuates mixed antibody-mediated renal allograft injury

Donor-specific antibodies (DSAs) are major mediators of renal allograft injury, and strategies to inhibit DSAs are important in promoting long-term graft survival. Triptolide exhibits a wide spectrum of antiinflammatory and immunosuppressive activities, and in autoimmune diseases it inhibits autoantibody levels. In this study, we investigated the suppressive role of triptolide in the generation of DSAs in transplant recipients. We found that triptolide treatment of skin allograft recipients in mice significantly suppressed the development of circulating anti-donor-specific IgG and effectively alleviated DSA-mediated renal allograft injury, which led to prolonged allograft survival. In vitro studies revealed that triptolide inhibited the differentiation of B cells into CD138⁺ CD27⁺⁺ plasma cells; reduced the levels of IgA, IgG, and IgM secreted by plasma cells; and repressed somatic hypermutation and class switch recombination of B cells. Moreover, triptolide-treated recipients showed reduced numbers of B cells, plasma cells, and memory B cells in spleens and decreased numbers of T, B, natural killer (NK) cells, and macrophages infiltrating grafts. These findings highlight the importance of triptolide in suppressing DSAs and establish triptolide as a novel therapeutic agent for antibody-mediated allograft rejection.

C5aR1 promotes acute pyelonephritis induced by uropathogenic E. coli

C5a receptor 1 (C5aR1) is a G protein-coupled receptor for C5a and also an N-linked glycosylated protein. In addition to myeloid cells, C5aR1 is expressed on epithelial cells. In this study, we examined the role of C5aR1 in bacterial adhesion/colonization of renal tubular epithelium and addressed the underlying mechanisms of this role. We show that acute kidney infection was significantly reduced in mice with genetic deletion or through pharmacologic inhibition of C5aR1 following bladder inoculation with uropathogenic E. coli (UPEC). This was associated with reduced expression of terminal α-mannosyl residues (Man; a ligand for type 1 fimbriae of E. coli) on the luminal surface of renal tubular epithelium and reduction of early UPEC colonization in these mice. Confocal microscopy demonstrated that UPEC bind to Man on the luminal surface of renal tubular epithelium. In vitro analyses showed that C5a stimulation enhances Man expression in renal tubular epithelial cells and subsequent bacterial adhesion, which, at least in part, is dependent on TNF-α driven by C5aR1-mediated intracellular signaling. Our findings demonstrate a previously unknown pathogenic role for C5aR1 in acute pyelonephritis, proposing a potentially novel mechanism by which C5a/C5aR1 signaling mediates upregulation of carbohydrate ligands on renal tubules to facilitate UPEC adhesion.

Collectin-11 Promotes the Development of Renal Tubulointerstitial Fibrosis

Collectin-11 is a recently described soluble C-type lectin, a pattern recognition molecule of the innate immune system that has distinct roles in host defense, embryonic development, and acute inflammation. However, little is known regarding the role of collectin-11 in tissue fibrosis. Here, we investigated collectin-11 in the context of renal ischemia-reperfusion injury. Compared with wild-type littermate controls, Collec11 deficient (CL-11^-/- ) mice had significantly reduced renal functional impairment, tubular injury, renal leukocyte infiltration, renal tissue inflammation/fibrogenesis, and collagen deposition in the kidneys after renal ischemia-reperfusion injury. In vitro, recombinant collectin-11 potently promoted leukocyte migration and renal fibroblast proliferation in a carbohydrate-dependent manner. Additionally, compared with wild-type kidney grafts, CL-11^-/-mice kidney grafts displayed significantly reduced tubular injury and collagen deposition after syngeneic kidney transplant. Our findings demonstrate a pathogenic role for collectin-11 in the development of tubulointerstitial fibrosis and suggest that local collectin-11 promotes this fibrosis through effects on leukocyte chemotaxis and renal fibroblast proliferation. This insight into the pathogenesis of tubulointerstitial fibrosis may have implications for CKD mediated by other causes as well.

Efficacy and safety of Tripterygium wilfordii hook F versus acitretin in moderate to severe psoriasis vulgaris: a randomized clinical trial

Background:

Few clinical trials have evaluated the efficacy and safety of Tripterygium wilfordii Hook F (TwHF) compared with acitretin in psoriasis. We aimed to compare the efficacy and safety of TwHF compared with acitretin in the treatment of moderate to severe psoriasis vulgaris.

Methods:

Adults with Psoriasis Area Severity Index (PASI) score ≥ 10 and psoriasis-affected body surface area ≥ 10% were randomized into a TwHF (20 mg, 3 times a day) or acitretin group (30 mg, once a day). The treatment course lasted for 8 weeks. Patients were assessed at baseline and at 2, 4, and 8 weeks. Laboratory tests were performed at baseline, week 4, and week 8. The data were analyzed using paired samples t-test or analysis of variance (ANOVA).

Results:

A total of 115 patients was enrolled (58 TwHF; 57 acitretin). The median PASI score improved in the TwHF group by 50.4% and in the acitretin group by 42.7%. There was no significant difference in median PASI improvement between two groups at 2, 4, and 8 weeks. There was also no significant difference in PASI 25, PASI 50, PASI 75, and PASI 90 response between the two groups at 2, 4, and 8 weeks. There was a significant increase in the level of aspartate transaminase and triglycerides in the TwHF group (P = 0.026 and P = 0.011, respectively). In the acitretin group, there was a significant increase in the level of alanine transaminase, cholesterol, and high-density lipoprotein (P = 0.030, P < 0.01, and P < 0.01, respectively).

Conclusions:

There was no significant difference in treatment efficacy between the TwHF and acitretin groups within 8 weeks, but there were fewer treatment-related adverse events in the TwHF group.

Computational prediction and experimental validation of low-affinity target of triptolide and its analogues

ERα as a novel low affinity target for triptolide and its analogues triptonide and triptriolide.

Triptolide: progress on research in pharmacodynamics and toxicology

ETHNOPHARMACOLOGICAL RELEVANCE

Tripterygium wilfordii Hook. f. (Tripterygium wilfordii), also known as Huangteng and gelsemium elegan, is a traditional Chinese medicine that has been marketed in China as Tripterygium wilfordii glycoside tablets. Triptolide (TP), an active component in Tripterygium wilfordii extracts, has been used to treat various diseases, including lupus, cancer, rheumatoid arthritis and nephritic syndrome. This review summarizes recent developments in the research on the pharmacodynamics, pharmacokinetics, pharmacy and toxicology of TP, with a focus on its novel mechanism of reducing toxicity. This review provides insight for future studies on traditional Chinese medicine, a field that is both historically and currently important.

MATERIALS AND METHODS

We included studies published primarily within the last five years that were available in online academic databases (e.g., PubMed, Google Scholar, CNKI, SciFinder and Web of Science).

RESULTS

TP has a long history of use in China because it displays multiple pharmacological activities, including anti-rheumatism, anti-inflammatory, anti-tumor and neuroprotective properties. It has been widely used for the treatment of various diseases, such as rheumatoid arthritis, nephritic syndrome, lupus, Behcet׳s disease and central nervous system diseases. Recently, numerous breakthroughs have been made in our understanding of the pharmacological efficacy of TP. Although TP has been marketed as a traditional Chinese medicine, its multi-organ toxicity prevents it from being widely used in clinical practice.

CONCLUSIONS

Triptolide, a biologically active natural product extracted from the root of Tripterygium wilfordii, has shown promising pharmacological effects, particularly as an anti-tumor agent. Currently, in anti-cancer research, more effort should be devoted to investigating effective anti-tumor targets and confirming the anti-tumor spectrum and clinical indications of novel anti-tumor pro-drugs. To apply TP appropriately, with high efficacy and low toxicity, the safety and non-toxic dose range for specific target organs and diseases should be determined, the altered pathways and mechanisms of exposure need to be clarified, and an early warning system for toxicity needs to be established. With further in-depth study of the efficacy and toxicity of TP, we believe that TP will become a promising multi-use drug with improved clinical efficacy and safety in the future.

Transcriptional profiling of belatacept and calcineurin inhibitor therapy in renal allograft recipients

Calcineurin inhibitor (CNI) use may lead to allograft injury and compromised renal function. Gene expression profiles of 12-month kidney biopsies from a Phase 3 study of belatacept and a CNI comparator, cyclosporine (CsA), were compared with expression profiles of a set of historical, demographically matched, preimplantation control biopsies. Gene set enrichment analysis was used to test each set of differentially expressed genes (DEGs) for the enrichment of an in vitro-derived CNI toxicity (CNIT) gene set and published gene sets associated with chronic allograft injury (CAI), immune modulation and tissue remodeling. The unique set of genes differentially expressed in CNI biopsies compared with preimplantation controls was enriched for genes associated with fibrosis, early tubulointerstitial damage and in vitro CNIT. The DEGs from belatacept biopsies were not enriched for the CNIT genes but, instead, exhibited enrichment for gene sets associated with immune response and tissue remodeling. A combined analysis of DEGs across both treatment groups identified select solute transporter and cellular differentiation genes whose expression at 12 months correlated with renal function at 36 months. These results provide mechanistic insights into the reduced CAI and higher renal function observed in belatacept- versus CsA-treated patients.

Tripterygium wilfordii Hook F (a traditional Chinese medicine) for primary nephrotic syndrome

BACKGROUND

Tripterygium wilfordii Hook F (TwHF), a traditional Chinese herbal medicine used as an immunosuppressive agent, has been prescribed in China for patients with primary nephrotic syndrome (NS) for more than two decades. Although patients with primary NS in China have benefited from TwHF treatment, its properties have not yet been fully understood.

OBJECTIVES

To assess the benefits and harms of TwHF for patients with primary NS.

SEARCH METHODS

We searched the Cochrane Renal Group's specialised register (August 2012), Cochrane Register of Controlled Trials (CENTRAL, The Cochrane Library 2012, Issue 8), EMBASE (1966 to August 2012), and MEDLINE (1966 to August 2012). We also searched CBM (Chinese Biological Medical Database) (1978 to November 2010), CNKI (Chinese National Knowledge Infrastructure) (1979 to November 2010), VIP (ChongQing WeiPu Chinese Science and Technology Periodical Database) (1989 to November 2010), WanFang Database (1980 to November 2010), and reference lists of articles (6 November 2010).

SELECTION CRITERIA

Only randomised controlled trials (RCTs) were included. Two standardised preparations of TwHF were investigated: ethanol-ethyl acetate extract and chloroform-methanol extract. All other TwHF preparations were excluded because of reported toxicities. Other traditional Chinese herbal medicines were also excluded. All included RCTs had a follow-up of at least three months.

DATA COLLECTION AND ANALYSIS

Data extraction and risk of bias assessment were undertaken independently by two authors. Where details of randomised sequence generation and allocation concealment were absent or inadequately reported, we contacted original study investigators for verification and details of the procedure. For dichotomous outcomes (remission and drug-related adverse events) we used risk ratio (RR) with 95% confidence intervals (95% CI) and mean difference (MD) for continuous outcomes (urinary protein excretion, serum albumin and serum creatinine).

MAIN RESULTS

Ten studies enrolling 630 participants were included. Overall, the quality of evidence was suboptimal due to the small number of included studies enrolling small numbers of participants; short follow-up in each study; only a few studies in each comparison category; and major concerns with methodological bias. Four studies (293 participants) contributed to the comparison of TwHF versus non-TwHF. TwHF significantly increased complete remission (RR 1.46, 95% CI 1.18 to 1.80) and complete or partial remission (RR 1.26, 95% CI 1.10 to 1.44) without escalating the adverse events profile at the last follow-up (12 to 16 months). Four studies (223 participants) compared TwHF with prednisone. There were no statistically significant differences between complete remission, partial remission, and complete or partial remission. Two studies (114 participants) contributed to the comparison of TwHF versus cyclophosphamide (CPA) at the last follow-up (3 to 12 months). There were no statistically significant differences between complete, partial, or complete or partial remission. One study (46 participants) reported TwHF was associated with a significantly lower serum creatinine compared with CPA (MD -14.00 μmol/L, 95% CI -26.43 to -1.57). No serious adverse events of TwHF were observed. One study (37 participants) reported TwHF was associated with a significantly lower risk of psychosis when compared to prednisone (RR 0.11, 95% CI 0.01 to 0.75), and two studies showed a significantly lower risk of hair loss with TwHF when compared to CPA ((2 studies, 114 participants): RR 0.11, 95% CI 0.02 to 0.59).

AUTHORS' CONCLUSIONS

TwHF may have an add-on effect on remission in patients with primary NS. There was insufficient evidence to assess if TwHF was as effective as prednisone or CPA. More methodologically sound and sufficiently powered studies, with adequate follow-up would help to better inform management options for the use of TwHF for primary NS. TwHF should be further directly compared with other widely used immunosuppressive agents after the superiority over placebo or no treatment has been clearly established.

Crosstalk between complement and Toll-like receptor activation in relation to donor brain death and renal ischemia-reperfusion injury

Two central pathways of innate immunity, complement and Toll-like receptors (TLRs), play an important role in the pathogenesis of renal injury inherent to kidney transplantation. Recent findings indicate close crosstalk between complement and TLR signaling pathways. It is suggested that mitogen activated protein kinases (MAPKs) might be the key molecules linking both the complement and TLR pathways together. Complement and TLRs are important mediators of renal ischemia-reperfusion injury (IRI). Besides IRI, complement C3 can also be upregulated and activated in the kidney before transplantation as a direct result of brain death (BD) in the donor. This local upregulation and activation of complement in the donor kidney has been proven to be detrimental for renal allograft outcome. Also TLR4 and several of its major ligands are upregulated by donor BD compared to living donors. Important and in line with the observations above, kidney transplant recipients have a benefit when receiving a kidney from a TLR4 Asp299Gly/Thr399Ile genotypic donor. The role of complement and TLRs and crosstalk between these two innate immune systems in relation to renal injury during donor BD and ischemia-reperfusion are focus of this review. Future strategies to target complement and TLR activation in kidney transplantation are considered.

Triptolide and its expanding multiple pharmacological functions

Triptolide, a diterpene triepoxide, is a major active component of extracts derived from the medicinal plant Tripterygium wilfordii Hook F (TWHF). Triptolide has multiple pharmacological activities including anti-inflammatory, immune modulation, antiproliferative and proapoptotic activity. So, triptolide has been widely used to treat inflammatory diseases, autoimmune diseases, organ transplantation and even tumors. Triptolide cannot only induce tumor cell apoptosis directly, but can also enhance apoptosis induced by cytotoxic agents such as TNF-α, TRAIL and chemotherapeutic agents regardless of p53 phenotype by inhibiting NFκB activation. Recently, the cellular targets of triptolide, such as MKP-1, HSP, 5-Lox, RNA polymerase and histone methyl-transferases had been demonstrated. However, the clinical use of triptolide is often limited by its severe toxicity and water-insolubility. New water-soluble triptolide derivatives have been designed and synthesized, such as PG490-88 or F60008, which have been shown to be safe and potent antitumor agent. Importantly, PG490-88 has been approved entry into Phase I clinical trial for treatment of prostate cancer in USA. This review will focus on these breakthrough findings of triptolide and its implications.

Triptolide inhibits extracellular matrix protein synthesis by suppressing the Smad2 but not the MAPK pathway in TGF-beta1-stimulated NRK-49F cells

BACKGROUND

Triptolide has been used for treating various autoimmune diseases. However, it remains unclear whether triptolide exerts effects on extracellular matrix (ECM) synthesis, which plays an important role in renal fibrosis.

METHODS

NRK-49F cells stimulated with TGF-β1 were incubated with triptolide in various concentrations. ECM proteins, including collagen type III and fibronectin, were detected using the reverse transcription real-time PCR and ELISA methods. MAPK and Smad2/3 phosphorylation were measured with western blot. P38 and ERK 1/2 pathways were inhibited with the specific inhibitors, SB203580 and PD98059. The Smad2 signal was blocked with the siRNA method.

RESULTS

Triptolide inhibited ECM synthesis in TGF-β1-stimulated NRK-49F cells in a concentration-dependent manner. Triptolide enhanced TGF-β1-induced activation of the p38, ERK 1/2 signals, whereas it inhibited Smad2 activation. There was no crosstalk between the p38, ERK 1/2 and Smad2 pathways in NRK-49F cells. Inhibition of either the p38 or ERK 1/2 signals reduced ECM synthesis. Triptolide downregulated synthesis of fibronectin and collagen type III in TGF-β1-stimulated cells treated with SB203580 and/or PD98059. SB203580 and/or PD98059 significantly repressed synthesis of fibronectin and collagen type III in TGF-β1-stimulated cells treated with triptolide. Smad2 inhibition by siRNA significantly reduced ECM synthesis. However, ECM synthesis in NRK-49F cells transfected with Smad2 siRNA and treated by triptolide was increased compared with Smad2 siRNA-transfected cells.

CONCLUSION

The effect of triptolide to suppress ECM synthesis by inhibiting Smad2 activation may surpass its stimulating effect on ECM synthesis by activation of p38 and ERK 1/2, leading to a total inhibition of ECM synthesis in TGF-β1-stimulated NRK-49F cells.

Dendritic cell function in allostimulation is modulated by C5aR signaling

Regulation of T cell immunity by C5a has been suggested from recent studies. However, the underlying mechanisms, particularly the involved cells and biochemical basis, are not well defined. In this study, the direct modulation of dendritic cell (DC) activation and its function in T cell stimulation by C5a-C5aR interaction and the involved signaling pathways were investigated. We show that DCs from C5aR(-/-) mice and normal DCs treated with C5aR antagonist have less-activated phenotype characterized with increased IL-10 and decreased IL-12p70 production in response to LPS stimulation, lowered surface expression of MHC class II, B7.2, and consequently have reduced capacity to stimulate allospecific T cells. Conversely, C5a stimulation up-regulates DC activation and its function in allostimulation. Furthermore, stimulation of C5aR mediates the inhibition of cAMP production and protein kinase A activity and is involved in activation of PI3K/AKT and NF-kappaB signaling in DCs. These results demonstrate that C5a acts directly on C5aR expressed on DCs resulting in the cell activation and subsequently enhances its capacity for allospecific T cell stimulation. It also suggests that NF-kappaB signaling induced by down-regulation of cAMP/ protein kinase A pathway and up-regulation of PI3K/AKT pathway following C5a stimulation may contribute to up-regulation of DC function.

Triptolide Attenuates Endotoxin- and Staphylococcal Exotoxin-Induced T-Cell Proliferation and Production of Cytokines and Chemokines

Proinflammatory cytokines mediate the toxic effects of superantigenic staphylococcal exotoxins (SE) and bacterial lipopolysaccharide (LPS). Triptolide, an oxygenated diterpene derived from a traditional Chinese medicinal herb, Tripterygium wilfordii, inhibited SE-stimulated T-cell proliferation (by 98%) and expression of interleukin 1beta, interleukin 6, tumor necrosis factor, gamma interferon, monocyte chemotactic protein 1, macrophage inflammatory protein (MIP)-1alpha, and MIP-1beta by human peripheral blood mononuclear cells (PBMC). It also blocked the production of these cytokines and chemokines by LPS-stimulated PBMC in a dose-dependent manner. These results suggest that triptolide has potent immunosuppressive effects even counteracting the effects of superantigens and LPS. It also may be therapeutically useful for mitigating the pathogenic effects of these microbial products by downregulating the signaling pathways activated by both bacterial exotoxins and endotoxins.

Complement and renal transplantation: from donor to recipient

Long-term kidney graft survival is affected by different variables including donor condition, ischemia-reperfusion injury, and graft rejection during the transplantation process. The complement system is an important mediator of renal ischemia-reperfusion injury and in rejecting allografts. However, donor complement C3 seems to be crucial in renal transplantation-related injury as renal injury is attenuated in C3 deficient kidney grafts. Interestingly, before ischemia-reperfusion induced C3 expression, C3 is already induced in donors suffering from brain death. Therefore, strategies targeting complement activation in the brain-dead donor may increase graft viability and transplant outcome.

Dense deposit disease and the factor H H402 allele

Herein, we describe the case of an 8-year-old boy who presented with a nephritic nephrotic syndrome. His laboratory investigation was significant for a persistently low serum complement 3 level. A renal biopsy was performed, based on which, he was diagnosed with dense deposit disease/membranoproliferative glomerulonephritis type II (DDD/MPGN II). He was treated with alternate-day oral corticosteroids, angiotensin-converting enzyme (ACE) inhibitors and tacrolimus. Factor H mutational analysis showed the Y402H and I62V allele polymorphisms. The purpose of our report is to discuss the association of the H402 allele variant of factor H with the DDD/MPGN II phenotype and its possible therapeutic implications.

Local production and activation of complement up-regulates the allostimulatory function of dendritic cells through C3a-C3aR interaction

Donor cell expression of C3 enhances the alloimmune response and is associated with the fate of transplantation. To clarify the mechanism for enhancement of the immune response, we have explored the role of C3a receptor (C3aR)-ligand interaction on murine bone marrow dendritic cells (DCs). We show that DCs either lacked receptor for C3a (a C3 cleavage product) or were treated with C3aR antagonist, elicited defective T-cell priming against alloantigen expressed on the DCs. This was associated with reduced surface expression of major histocompatibility complex (MHC) and costimulatory molecules on the DCs, and with defective priming in skin allograft rejection. In addition, DCs lacking factor B were unable to generate potent T-cell responses against donor antigen, whereas lack of C4 had no detectable effect, suggesting a role for the alternative pathway contributing to allostimulation. Furthermore, therapeutic complement regulator can down-regulate DC allostimulatory function. These findings suggest that the capacity of DCs for allostimulation depends on their ability to express, activate, and detect relevant complement components leading to C3aR signaling. This mechanism, in addition to underpinning the cell-autonomous action of donor C3 on allostimulation, has implications for a wider range of immune responses in self-restricted T-cell priming.

The relative importance of local and systemic complement production in ischaemia, transplantation and other pathologies

Besides a critical role in innate host defence, complement activation contributes to inflammatory and immunological responses in a number of pathological conditions. Many tissues outside the liver (the primary source of complement) synthesise a variety of complement proteins, either constitutively or response to noxious stimuli. The significance of this local synthesis of complement has become clearer as a result of functional studies. It revealed that local production not only contributes to the systemic pool of complement but also influences local tissue injury and provides a link with the antigen-specific immune response. Extravascular production of complement seems particularly important at locations with poor access to circulating components and at sites of tissue stress responses, notably portals of entry of invasive microbes, such as interstitial spaces and renal tubular epithelial surfaces. Understanding the relative importance of local and systemic complement production at such locations could help to explain the differential involvement of complement in organ-specific pathology and inform the design of complement-based therapy. Here, we will describe the lessons we have learned over the last decade about the local synthesis of complement and its association with inflammatory and immunological diseases, placing emphasis on the role of local synthesis of complement in organ transplantation.

Clinical trial of Tripterygium Wilfordii Hook F. in human kidney transplantation in China

OBJECTIVE

In this study, the effects of Triptergium Wilfordii Hook F.(T II) were assessed on human kidney allograft rejection and long-term survival.

METHODS

This study compared treatment with T II(T II group, n=121) to that without T II(control group, n=102) among adult first cadaveric renal transplant recipients. The T II cohort of 121 recipients were divided into a regular dosage group (n=82) and a double dosage group (n=39). No antibody induction was administered to any patient.

RESULTS

Biopsy-proven early acute allograft rejection occurred in 4.1% of patients in the T II group versus 24.5% of patients in the control group. No rejection or repeated rejections occurred in the double dosage group at 3 months after transplantation. Acute rejection episodes were milder in the T II than the control group. The incidence of CD25+ cells>10/ mm3 in the allografts at 3 months after transplantation was lower in the T II group than the control group, 15% and 50%, respectively. All patients tolerated T II well over the 5 years of this study. The 5-year graft survival censored for death with function was 96.7% in the T II group and 80.4% in the control group.

CONCLUSION

T II was effective to prevent renal allograft rejection and increase long-term renal allograft survival among adult cadaveric renal transplant recipients.

CD46 (Membrane Cofactor Protein) Acts as a Human Epithelial Cell Receptor for Internalization of Opsonized UropathogenicEscherichia coli

Escherichia coli is a common urinary pathogen whose uptake into epithelial cells is mediated by attachment through type 1 fimbriae. In this study, we show by using using human urinary tract epithelial cells that maximal internalization of E. coli is achieved only when bacteria are opsonized with complement. The concentrations of complement proteins in the urine rise sufficiently during infection to allow bacterial opsonization. The complement regulatory protein, CD46 (membrane cofactor protein), acts in cohort with fimbrial adhesion to promote the uptake of pathogenic E. coli. This uptake is inhibited by RNA interference to lower the expression of CD46 and by soluble CD46 that will competitively inhibit opsonized bacteria binding to cell surface CD46. We propose that efficient internalization of uropathogenic E. coli by the human urinary tract depends on cooperation between fimbrial-mediated adhesion and C3 receptor (CD46)-ligand interaction. Complement receptor-ligand interaction could pose a new target for interrupting the cycle of reinfection due to intracellular bacteria.

A synergistic effect between PG490-88 and tacrolimus prolongs renal allograft survival in monkeys

This study was undertaken to determine if PG490-88 and tacrolimus (Tac) act synergistically to prevent renal allograft rejection in monkeys and to explore possible mechanisms of synergy between these agents. MHC-mismatched renal allografts were transplanted into cynomolgus monkeys after bilateral nephrectomy. Recipients were divided into the following groups: (i) no treatment; (ii) PG490-88 (0.03 mg/kg); (iii) Tac (1 mg/kg); (iv) PG490-88 (0.01 mg/kg) + Tac (1 mg/kg) and (v) PG490-88 (0.03 mg/kg) + Tac (1 mg/kg). Through synergy PG490-88 and Tac inhibited anti-CD3/PMA-induced T-cell proliferation and IFN-gamma expression in vitro. Tac monotherapy only marginally prolonged survival (27 +/- 3.2 days), while the combination of PG490-88 and Tac significantly prolonged graft survival to a median of 99 days (PG490-88 at 0.03 mg) and 38.5 days (PG490-88 at 0.01 mg/kg). Prolonged survival correlated with inhibited IgM production as well as reduced T-cell infiltration, IL-2 protein expression and NF-AT/NF-kappaB activity. We conclude that PG490-88 and a subtherapeutic dose of Tac significantly prolong renal allograft survival in monkeys through the synergistic inhibition of T-cell activation and a decrease in IFN-gamma production and NF-AT/NF-kappaB activity.

Macrophages from C3-deficient mice have impaired potency to stimulate alloreactive T cells

Impaired T-cell reactivity is a feature of C3-deficient mice in several disease models. The mechanism behind the reduced T-cell response is, however, poorly understood. We explored the hypothesis that antigen-presenting cells (APCs) from C3-/- mice have impaired potency to stimulate antigen-specific T cells, in an alloantigen-dependent model. Our results show that C3-/- macrophages have reduced ability to elicit alloreactive T-cell responses in vitro and in vivo, affecting both the primary and secondary responses. The C3 status of donor macrophages had a major impact on the CD4 T-cell response. The impaired CD4 T-cell response was associated with reduced expression of MHC class II on the surface of C3-/- macrophages, without loss of class II gene expression. Furthermore, inhibition of C3 gene expression in C3+/+ macrophages reduced their ability to stimulate alloreactive T cells, suggesting that endogenous production of C3 could in part contribute to the potency of APCs. Our data provide compelling evidence that C3 deficiency modulates the potency of APCs to stimulate the T-cell response, suggesting a critical role for complement in the maintenance of APC function. This could offer a partial explanation as to why the T-cell response is impaired in C3-/- mice. (Blood. 2006;107:2461-2469)

Allograft rejection: effect of local synthesis of complement

The complement system is known for its ability to participate in non-specific inflammation and membrane injury as well as contributing to antigen-specific immune stimulation. In renal transplantation, the complement cascade behaves true to form in that both non-immune- and immune-mediated destruction of the renal tubules are complement dependent. What is remarkable, however, is the extent of involvement of local synthesis of complement in both of these injuries, suggesting that the extravascular tissue compartment is the domain of local synthesis, whereas the effect of circulating complement is much less. This creates a new paradigm for studying the influence of local synthesis of complement in other organ-based diseases and underlines the need for tissue-targeting strategies in successful therapeutic development.

Triptolide affects the differentiation, maturation and function of human dendritic cells

Triptolide is a purified component from a traditional Chinese herb Tripterygium wilfordii Hook F. It has been shown to have anti-inflammatory and immunosuppressive activities by its inhibitory effect on T cells. But the effect of triptolide on dendritic cells (DC) is unknown. Dexamethasone (Dex) is a classic immunosuppressive agent known to suppress the immune response at different levels and has recently found to modulate the development of DC, thereby influencing the initiation of the immune response. In this study, we investigated the affect of triptolide on the differentiation, maturation and function of DC differentiated from human monocytes (MoDC) in vitro in the presence of GM-CSF and IL-4. Dex was included in the study as a reference. Our data show that both triptolide and Dex prevented the differentiation in immature MoDC by inhibiting CD1a, CD40, CD80, CD86 and HLA-DR expression but upregulating CD14 expression, as well as by reducing the capacity of MoDC to stimulate lymphocyte proliferation in the allogeneic mixed lymphocyte reaction. They blocked the maturation of MoDC as totally blocked induction of CD83 expression and absent upregulation of CD40, CD80, CD86 and HLA-DR. In addition, higher concentration of triptolide (20 ng/ml) and 10(-6) M Dex induced apoptosis in MoDC as measured by expression of APO2*7 and DNA fragmentation (TUNEL assay). However, the phagocytic capacity of MoDC was enhanced by triptolide but not Dex. Therefore, the suppression of DC differentiation, the function in immature DCs as well as the inhibition of DC maturation by triptolide may explain some of its immunosuppressive properties. It is suggested that DCs are a primary target of the immunosuppressive activity of triptolide.

Triptolide inhibits B7-H1 expression on proinflammatory factor activated renal tubular epithelial cells by decreasing NF-kappaB transcription

Triptolide has been used extensively in China for the treatment of autoimmune diseases and tumor for many centuries. Nevertheless, little is known about its exact immunosuppressive and anti-inflammatory properties. Increasing recognition of the importance of renal tubular epithelial cells (TECs) in renal diseases raises the question whether triptolide can regulate TEC activity. In this study, various cultured human and murine TECs were exposed to tumor necrotic factor-alpha (TNF-alpha) and triptolide, followed to examine the expression of B7-H1 and B7-DC. Flow cytometric analysis revealed that B7-H1 but not B7-DC constitutively expresses on TECs, and the B7-H1 protein expression was profoundly up-regulated by the stimulation of TNF-alpha with a dose-dependent manner. However, triptolide under non-cytotoxic concentration could down-regulate B7-H1 expression on activated TECs at both mRNA and protein level. This effect was transcription factor NF-kappaB dependent. Interestingly, the significant damping effect of triptolide on B7-H1 signal could promote interleukin-2 production by T cell hybridoma (C10) after antigen presentation and enhance cytokine (IFN-gamma and IL-2) secretion by anti-CD3 activated T cells. Our results indicated that triptolide could regulate TEC activity via B7-H1, in addition to previously reported it directly affects the production of some inflammatory factors by T cells, tumor cells and peripheral blood mononuclear cells.

Immunosuppression with a Combination of Pg490–88 and a Subtherapeutic Dose of FK506 in a Canine Renal Allograft Model

BACKGROUND

PG490-88 is a water soluble, semisynthetic derivative of a novel compound PG490 (triptolide) purified from the Chinese herb Tripterygium Wilfordii Hook F. In this study, we evaluated the immunosuppressive effect of PG490-88 alone or combined with FK506 in a dog renal transplantation model.

METHODS

Recipient and donor male beagle dogs were obtained from different breeders to ensure MHC mismatching. PG490-88 and/or FK506 were administered orally based on protocol design.

RESULTS

All dogs in the untreated group developed acute vascular rejection with a median survival time of 6 days. The grafts from this group presented with massive hemorrhage, IgM, IgG, and C4c deposition. Administration of PG490-88 0.06 mg/kg/day significantly prolonged graft survival to a median survival time of 11 days (P=0.038, vs. control). Treatment with FK506 0.3 mg/kg/day did not prolong graft survival with a median survival time of 9 days. Although FK506 0.6 mg/kg/day significantly prolonged survival, this dose was not tolerated by the dogs. The combination of PG 0.06 mg/kg/day and FK506 0.3 mg/kg/day significantly prolonged survival to a median survival time of 15 days (P=0.017, vs. control). Compared to the untreated control group, the pattern of acute humoral rejection was attenuated in renal allografts treated with PG490-88 and/or FK506. C4c deposition was significantly decreased in renal allografts treated with PG490-88 monotherapy and combination therapy.

CONCLUSIONS

PG490-88 alone and combined with low dose FK506 significantly prolonged renal allograft survival in a dog model. This agent attenuated acute humoral rejection by inhibiting complement activation and T-cell infiltration.

Characterization of renal interstitial fibroblast-specific protein 1/S100A4-positive cells in healthy and inflamed rodent kidneys

Fibrosis is considered as a central factor in the loss of renal function in chronic kidney diseases. The origin of fibroblasts and myofibroblasts that accumulate in the interstitium of the diseased kidney is still a matter of debate. It has been shown that accumulation of myofibroblasts in inflamed and fibrotic kidneys is associated with upregulation of fibroblast-specific protein 1 (FSP1, S100A4), not only in the renal interstitium but also in the injured renal epithelia. The tubular expression of FSP1 has been taken as evidence of myofibroblast formation by epithelial-mesenchymal transition (EMT). The identity of FSP1/S100A4 cells has not been defined in detail. We originally intended to use FSP1/S100A4 as a marker of putative EMT in a model of distal tubular injury. However, since the immunoreactivity of FSP1 did not seem to fit with the distribution and shape of fibroblasts or myofibroblasts, we undertook the characterization of FSP1/S100A4-expressing cells in the interstitium of rodent kidneys. We performed immunolabeling for FSP1/S100A4 on thin cryostat sections of perfusion-fixed rat and mouse kidneys with peritubular inflammation, induced by thiazides and glomerulonephritis, respectively, in combination with ecto-5'-nucleotidase (5'NT), recognizing local cortical peritubular fibroblasts, with CD45, MHC class II, CD3, CD4 and Thy 1, recognizing mononuclear cells, with alpha smooth muscle actin (alphaSMA), as marker for myofibroblasts, and vimentin for intracellular intermediate filaments in cells of mesenchymal origin. In the healthy interstitium of rodents the rare FSP1/S100A4+ cells consistently co-expressed CD45 or lymphocyte surface molecules. Around the injured distal tubules of rats treated for 3-4 days with thiazides, FSP1+/S100A4+, 5'NT+, alphaSMA+, CD45+ and MHC class II+ cells accumulated. FSP1+/S100A4+ cells consistently co-expressed CD45. In the inflamed regions, alphaSMA was co-expressed by 5'NT+ cells. In glomerulonephritic mice, FSP1+/S100A4+ cells co-expressed Thy 1, CD4 or CD3. Thus, in the inflamed interstitium around distal tubules of rats and of glomerulonephritic mice, the majority of FSP1+ cells express markers of mononuclear cells. Consequently, the usefulness of FSP1/S100A4 as a tool for detection of (myo)fibroblasts in inflamed kidneys and of EMT in vivo is put into question. In the given rat model the consistent co-expression of alphaSMA and 5'NT suggests that myofibroblasts originate from resident peritubular fibroblasts.

Membranoproliferative glomerulonephritis type II (dense deposit disease): an update

Membranoproliferative glomerulonephritis type II (MPGN II) is a rare disease characterized by the deposition of abnormal electron-dense material within the glomerular basement membrane of the kidney and often within Bruch's membrane in the eye. The diagnosis is made in most patients between the ages of 5 and 15 yr, and within 10 yr, approximately half progress to end-stage renal disease, occasionally with the late comorbidity of visual impairment. The pathophysiologic basis of MPGN II is associated with the uncontrolled systemic activation of the alternative pathway (AP) of the complement cascade. In most patients, loss of complement regulation is caused by C3 nephritic factor, an autoantibody directed against the C3 convertase of the AP, but in some patients, mutations in the factor H gene have been identified. For the latter patients, plasma replacement therapy prevents renal failure, but for the majority of patients, there is no proven effective treatment. The disease recurs in virtually all renal allografts, and a high percentage of these ultimately fail. The development of molecular diagnostic tools and new therapies directed at controlling the AP of the complement cascade either locally in the kidney or at the systemic level may lead to effective treatments for MPGN II.

Triptolide suppresses CD80 and CD86 expressions and IL-12 production in THP-1 cells

AIM

To investigate the effects of triptolide, a diterpenoid triepoxide from Tripterygium wilfordii Hook F (TWHF), on the co-stimulatory molecule expression and interleukin-12 (IL-12) production from THP-1 cells.

METHODS

THP-1 cells were differentiated into macrophage-like cells by Me2SO, and then cultured with IFN-gamma (500 kU/L) and lipopolysaccharide (LPS) (1 mg/L) with or without triptolide. The surface molecule expressions were analyzed on a FACScan flow cytometer. IL-12p40, IL-12p70 were assayed by ELISA.

RESULTS

Triptolide suppressed CD80 and CD86 expressions on IFN-gamma (500 kU/L) and LPS (1 mg/L) activated THP-1 cells at nontoxic dosages of 2.5-0.625 microg/L. Furthermore, the production of IL-12p40 and IL-12p70 were also significantly reduced in THP-1 cells exposed to triptolide.

CONCLUSION

Triptolide impairs the antigen-presenting function by inhibiting CD80 and CD86 expressions and decreased IL-12p40 and IL-12p70 (bioactive form) productions from the activated THP-1 cells.

The immunological synapse for B-cell memory: the role of the ICOS and its ligand for the longevity of humoral immunity

RECENT FINDINGS

The ICOS is one of the many costimulatory molecules of T cells. Recently, the authors discovered that the homozygous loss of the ICOS in humans presents as common variable immunodeficiency, the most prevalent treated primary immunodeficiency in man. Therefore, the ICOS is after CD40 and CD40-ligand deficiency the third costimulatory molecule for which a human disease has been described.

PURPOSE OF REVIEW

The description of ICOS deficiency made it necessary to review the vast amount of knowledge from experimental models in the light of a new clinical immunodeficiency phenotype. To this end, after introducing the ICOS and its ligand and comparing the murine and human 'knockout', the role of the ICOS in parasitic and viral infections, asthma, autoimmunity, transplantation immunology, and tumor surveillance will be discussed.

SUMMARY

The focus of this review is the interaction between the ICOS and its ligand, which is essential for T cell dependent B cell responses.

Role of the complement system in rejection

The complement system plays a complex role in transplantation, beginning with effects on reperfusion injury and continuing with stimulation of the adaptive immune response. Recent evidence has emphasised the importance of the late components of the complement cascade in the mediation of post-ischaemic damage, which are apparently triggered by the classical, alternative or lectin pathways of complement activation, depending on the organ affected. In studies of renal allograft rejection, the local synthesis of complement component C3 seems to influence the T-cell response more strongly than circulating complement protein, raising the possibility that there is co-operation between locally derived C3 and antigen presentation in the graft. Class switching of alloantibody to a high-affinity IgG response is also highly dependent on C3. In addition, the finding that capillary-bound C4d is a robust marker for humoral rejection has started a new investigation into the significance of alloantibodies in acute and chronic allograft rejection. There are several selective and nonselective inhibitors suitable for clinical development; clearly it is time for more concerted effort to evaluate their role in clinical transplantation.