Combined treatment with triptolide and rapamycin prolongs graft survival in a mouse model of cardiac transplantation

Bispecific antibodies tethering innate receptors induce human tolerant-dendritic cells and regulatory T cells

There is an urgent need for alternative therapies targeting human dendritic cells (DCs) that could reverse inflammatory syndromes in many autoimmune and inflammatory diseases and organ transplantations. Here, we describe a bispecific antibody (bsAb) strategy tethering two pathogen-recognition receptors at the surface of human DCs. This cross-linking switches DCs into a tolerant profile able to induce regulatory T-cell differentiation. The bsAbs, not parental Abs, induced interleukin 10 and transforming growth factor β1 secretion in monocyte-derived DCs and human peripheral blood mononuclear cells. In addition, they induced interleukin 10 secretion by synovial fluid cells in rheumatoid arthritis and gout patients. This concept of bsAb-induced tethering of surface pathogen-recognition receptors switching cell properties opens a new therapeutic avenue for controlling inflammation and restoring immune tolerance.

Monomethyl fumarate prevents alloimmune rejection in mouse heart transplantation by inducing tolerogenic dendritic cells

Dendritic cells (DCs) are important targets for eliciting allograft rejection after transplantation. Previous studies have demonstrated that metabolic reprogramming of DCs can transform their immune functions and induce their differentiation into tolerogenic DCs. In this study, we aim to investigate the protective effects and mechanisms of monomethyl fumarate (MMF), a bioactive metabolite of fumaric acid esters, in a mouse model of allogeneic heart transplantation. Bone marrow-derived DCs are harvested and treated with MMF to determine the impact of MMF on the phenotype and immunosuppressive function of DCs by flow cytometry and T-cell proliferation assays. RNA sequencing and Seahorse analyses are performed for mature DCs and MMF-treated DCs (MMF-DCs) to investigate the underlying mechanism. Our results show that MMF prolongs the survival time of heart grafts and inhibits the activation of DCs in vivo. MMF-DCs exhibit a tolerogenic phenotype and function in vitro. RNA sequencing and Seahorse analyses reveal that MMF activates the Nrf2 pathway and mediates metabolic reprogramming. Additionally, MMF-DC infusion prolongs cardiac allograft survival, induces regulatory T cells, and inhibits T-cell activation. MMF prevents allograft rejection in mouse heart transplantation by inducing tolerogenic DCs.

Tripterygium hypoglaucum (Lévl.) Hutch and Its Main Bioactive Components: Recent Advances in Pharmacological Activity, Pharmacokinetics and Potential Toxicity

Tripterygium hypoglaucum (Lévl.) Hutch (THH) is believed to play an important role in health care and disease treatment according to traditional Chinese medicine. Moreover, it is also the representative of medicine with both significant efficacy and potential toxicity. This characteristic causes THH hard for embracing and fearing. In order to verify its prospect for clinic, a wide variety of studies were carried out in the most recent years. However, there has not been any review about THH yet. Therefore, this review summarized its characteristic of components, pharmacological effect, pharmacokinetics and toxicity to comprehensively shed light on the potential clinical application. More than 120 secondary metabolites including terpenoids, alkaloids, glycosides, sugars, organic acids, oleanolic acid, polysaccharides and other components were found in THH based on phytochemical research. All these components might be the pharmacological bases for immunosuppression, anti-inflammatory and anti-tumour effect. In addition, recent studies found that THH and its bioactive compounds also demonstrated remarkable effect on obesity, insulin resistance, fertility and infection of virus. The main mechanism seemed to be closely related to regulation the balance of immune, inflammation, apoptosis and so on in various disease. Furthermore, the study of pharmacokinetics revealed quick elimination of the main component triptolide. The feature of celastrol was also investigated by several models. Finally, the side effect of THH was thought to be the key for its limitation in clinical application. A series of reports indicated that multiple organs or systems including liver, kidney and genital system were involved in the toxicity. Its potential serious problem in liver was paid specific attention in recent years. In summary, considering the significant effect and potential toxicity of THH as well as its components, the combined medication to inhibit the toxicity, maintain effect might be a promising method for clinical conversion. Modern advanced technology such as structure optimization might be another way to reach the efficacy and safety. Thus, THH is still a crucial plant which remains for further investigation.

Tethering Innate Surface Receptors on Dendritic Cells: A New Avenue for Immune Tolerance Induction?

Dendritic cells (DCs) play a key role in immunity and are highly potent at presenting antigens and orienting the immune response. Depending on the environmental signals, DCs could turn the immune response toward immunity or immune tolerance. Several subsets of DCs have been described, with each expressing various surface receptors and all participating in DC-associated immune functions according to their specific skills. DC subsets could also contribute to the vicious circle of inflammation in immune diseases and establishment of immune tolerance in cancer. They appear to be appropriate targets in the control of inflammatory diseases or regulation of autoimmune responses. For all these reasons, in situ DC targeting with therapeutic antibodies seems to be a suitable way of modulating the entire immune system. At present, the field of antibody-based therapies has mainly been developed in oncology, but it is undergoing remarkable expansion thanks to a wide variety of antibody formats and their related functions. Moreover, current knowledge of DC biology may open new avenues for targeting and modulating the different DC subsets. Based on an update of pathogen recognition receptor expression profiles in human DC subsets, this review evaluates the possibility of inducing tolerant DCs using antibody-based therapeutic agents.

Spontaneous hemangioendothelial cell hyperplasia of the heart in a young ICR mouse

Spontaneous nonneoplastic proliferative lesions of the cardiac hemangioendothelium are extremely rare in humans and animals. Here, we describe a spontaneous hemangioendothelial cell hyperplasia in the heart of a 9-week-old male ICR mouse. The lesion was observed focally in the interventricular septum, with no compression of the surrounding tissues. In the lesion, a single layer of hemangioendothelial cells that had a polygonal shape with enlarged nuclei and plump cytoplasm closely lined surrounding widened capillary vascular spaces and cardiac muscles. There was little cellular atypia, and there were no multilayered endothelial cells. Immunohistochemical staining revealed that these cells were partly positive for factor VIII and CD31, hemangioendothelial cell markers, and negative for Ki-67. These features were consistent with those in aged female B6C3F₁ mice in the only report in mice of spontaneous cardiac hemangioendothelial cell hyperplasia. Therefore, this is the first report of spontaneous hemangioendothelial cell hyperplasia in the heart of a young mouse.

Triptolide inhibits CD4+ memory T cell-mediated acute rejection and prolongs cardiac allograft survival in mice

There have been numerous investigations into the immunosuppressive effects of triptolide; however, its inhibitory effects on memory T cells remain to be elucidated. Using a cluster of differentiation (CD)4⁺ memory T-cell transfer model, the aim of the present study was to determine the inhibitory effects of triptolide on CD4⁺ memory T cell-mediated acute rejection and to determine the potential underlying mechanisms. At 4 weeks after skin transplantation, mouse cervical heart transplantation was performed following the transfer of CD4⁺ memory T cells. Mice were divided into two groups: A Control [normal saline, 30 ml/kg/day; intraperitoneal injection (ip)] and a triptolide group (triptolide, 3 mg/kg/day; ip). Graft survival, pathological examination and the corresponding International Society for Heart & Lung Transplantation (ISHLT) scores were assessed 5 days following heart transplantation, and levels of interleukin (IL)-2, interferon-γ (IFN-γ), IL-10 and transforming growth factor β1 (TGF-β1) in cardiac grafts and peripheral blood were assessed using reverse transcription-quantitative polymerase chain reaction and ELISA. The duration of cardiac graft survival in the triptolide group was significantly increased compared with the control group (14.3±0.4 vs. 5.3±0.2 days; P<0.001). Further pathological examinations revealed that the infiltration of inflammatory cells and myocardial damage in the cardiac grafts was notably reduced by triptolide, and the corresponding ISHLT scores in the triptolide group were significantly lower than those of the control group (grade 2.08±0.15 vs. 3.67±0.17; P<0.001). In addition, triptolide was able to significantly reduce IL-2 and IFN-γ secretion (P<0.01), significantly increase TGF-β1 secretion in the cardiac grafts and peripheral blood (P<0.01) and increase IL-10 secretion in the cardiac grafts. Therefore, the present study suggests that triptolide inhibits CD4⁺ memory T cell-mediated acute rejection and prolongs cardiac allograft survival in mice. This effect may be mediated by the inhibition of cytokine secretion by type 1 T helper cells and promotion of regulatory T cell proliferation.

Interleukin 6 inhibition by triptolide prevents inflammation in a mouse model of ulcerative colitis

The present study aimed to assess interleukin (IL)-6 expression in a murine model of ulcerative colitis (UC) induced by dextran sulfate sodium (DSS) and its potential association with the anti-colitis effects of triptolide (TL). Serum IL-6 levels were measured by ELISA. IL-6 gene expression levels in colonic mucosa specimens were assessed by reverse-transcription quantitative PCR and protein expression was evaluated by western blot analysis and immunohistochemistry. The expression of IL-6 was weak in mucosa specimens from normal control animals and upregulated in DSS-induced mice. In model mice treated with TL (0.4 and 0.6 mg/kg), dexamethasone or mesalazine, IL-6 expression was significantly reduced compared with that in model mice treated with normal saline or propylene glycol (P<0.05), while TL at 0.2 mg/kg did not elicit any significant inhibitory effect. There was no significant difference among TL (0.4 mg/kg and 0.6 mg/kg), mesalazine and dexamethasone treatments (P>0.05) in terms of IL-6 expression or histological score. The results of the present study indicated that IL-6 was overexpressed in a mouse model of UC and was involved in disease progression. In addition, TL exerted therapeutic effects in UC through inhibition of IL-6 expression.

Comparative analysis of four terpenoids in root and cortex of Tripterygium wilfordii Radix by different drying methods

Background

Tripterygium wilfordii Radix, a well-known traditional medicine in china which is used for treatment of inflammation, pain, tumor and immune regulation for centuries in china, accompany with the serious toxic side effects. This study was carried out for simultaneously analyzing the four main components (triptolide, triptophenolide, demethylzeylasteral and celastrol) in Tripterygium wilfordii Radix under different drying processes, which was important for reducing the toxicity and quality control of Tripterygium wilfordii Radix in future.

Methods

The terpenes were extracted by using ultrasonic method with ethyl acetate from root or cortex of Tripterygium wilfordii Radix, and the sensitive and rapid HPLC-PDA method was developed for simultaneous quantification of triptolide, triptophenolide, demethylzeylasteral and celastrol in root and cortex of Tripterygium wilfordii Radix for evaluation of the impacts by different drying processes.

Results

The four compounds in their respective determined arrange had good linearity of 0.9998≦R²≦0.9999 and the average recoveries were range from 94.69 to 100.28%, RSDs were within 0.27 to 2.42%, respectively. The contents of triptolide, triptophenolide, demethylzeylasteral and celastrol in different Tripterygium wilfordii Radix individuals were varied greatly at different drying temperatures. Under different temperatures, the contents of triptolide, triptophenolide, demethylzeylasteral, and celastrol were 37.94–70.31 mg/g, 0–1.807 mg/g, 0.3513–9.205 mg/g, 3.202–15.31 mg/g, respectively. The suitable drying temperature of terpenoids in root of wild and cultivate are 80 °C and 60 °C, the suitable drying temperature of terpenoids in cortex is 40 °C.

Conclusions

The method established is high sensitivity, accuracy, reliability and suitable for the simultaneous analysis of terpenoids in Tripterygium wilfordii Radix. The data provide a scientific basis and reference for the quality control of herb and preparations related to Tripterygium wilfordii Radix.

Immunoglobulin G promotes skin graft acceptance in an immunologically potent rat model

Immunoglobulin G (IgG) has been shown to protect graft rejection after transplantation, whereas the molecular mechanism of IgG in promoting graft acceptance has not been well established. In this study, we tested the effectiveness of IgG in preventing rejection of transplanted skin graft in an immunologically potent rat model, and studied the mechanism of this protection. We found that systemic or local administration of IgG significantly prolonged the survival of skin grafts with the immune tolerance induced by IgG and subcutaneous local injection of 1mg IgG to adult SD rat yielded the longest survival of skin grafts from 5.8 to 17.3 days. We also found that IgG reduced the number of pro-inflammatory cells especially lymphocytes, neutrophils and basophils, increased the seral levels of anti-inflammatory factors including IL-10 and IL-4, and activated CD4+CD25+Foxp3+ regulatory T cells, unveiling the mechanisms of this protective effect. These findings provide new insight to support clinical application of IgG in treating transplantation.

In vivo induction of regulatory T cells for immune tolerance in hemophilia

Current therapy for the X-linked coagulation disorder hemophilia is based on intravenous infusion of the specifically deficient coagulation factor. However, 20-30% of hemophilia A patients (factor VIII, FVIII, deficiency) generate inhibitory antibodies against FVIII. While formation of inhibitors directed against factor IX, FIX, resulting from hemophilia B treatment is comparatively rare, a serious complication that is often associated with additional immunotoxicities, e.g. anaphylaxis, occurs. Current immune tolerance protocols to eradiate inhibitors are lengthy, expensive, not effective in all patients, and there are no prophylactic tolerance regimens to prevent inhibitor formation. The outcomes of recent experiments in animal models of hemophilia demonstrate that regulatory CD4(+) T cells (Treg) are of paramount importance in controlling B cell responses to FVIII and FIX. This article reviews several novel strategies designed to in vivo induce coagulation factor-specific Treg cells and discusses the subsets of Treg that may promote immune tolerance in hemophilia. Among others, drug- and gene transfer-based protocols, lymphocyte transplant, and oral tolerance are reviewed.

Anti-inflammatory effects of triptolide improve left ventricular function in a rat model of diabetic cardiomyopathy

Aims

Given the importance of inflammation in the onset and progression of diabetic cardiomyopathy, we investigated the potential protective effects of triptolide, an anti-inflammatory agent, in streptozotocin-induced diabetic rat model and in H9c2 rat cardiac cells exposed to high glucose.

Methods and results

Diabetic rats were treated with triptolide (100, 200, or 400 μg/kg/day respectively) for 6 weeks. At the end of this study, after cardiac function measurements were performed, rats were sacrificed and their hearts were harvested for further histologic and molecular biologic analysis. Enhanced activity and expression of nuclear factor-kappaB (NF-κB) p65 in diabetic hearts were associated with increased inflammatory response, as demonstrated by increased pro-inflammatory cytokines, cell adhesion molecules and invading inflammatory cells, as well as increased fibrosis, in line with impaired left ventricular function. Triptolide attenuated these morpho-functional alterations. Furthermore, triptolide (20 ng/ml) also attenuated high glucose-induced inflammation in H9c2 rat cardiac cells.

Conclusion

Our data demonstrate that anti-inflammatory effects of triptolide involving the NF-κB signaling pathway can improve left ventricular function under diabetic conditions, suggesting triptolide treatment might be beneficial in diabetic cardiomyopathy.

Triptolide-conditioned dendritic cells induce allospecific T-cell regulation and prolong renal graft survival

BACKGROUND

Previous studies show that triptolide (TPT), a diterpenoid isolated from the Chinese herb Tripterygium wilfordii Hook.f, inhibits dendritic cell (DCs) maturation. Whether TPT-conditioned DCs (TPT-DCs) may regulate allospecific immune responses remains unclear. In this study, we investigated the effects of TPT on allostimulatory function and phenotype of rat bone marrow-derived DCs (BMDCs).

METHODS

Brown Norway rats BMDCs were cultured with or without TPT and then stimulated with lipopolysaccharide (LPS). IL-10 in supernatants was quantitatively measured, and the cells were analyzed by flow cytometry and used as stimulators in mixed leukocyte reaction in which naive Lewis rat T lymphocytes were used as responders. The tolerogenic potential of TPT-BMDCs was evaluated in vivo in a rat model of MHC fully mismatched kidney transplantation.

RESULTS

After treatment with TPT, BMDCs remained immature with low expression of CD80 and CD86 in the presence of LPS. At low concentrations of TPT (1 and 2.5 nM), BMDCs produced higher levels of IL-10 than the untreated cells (431 and 205.4 pg/ml, respectively, vs. 122.9 pg/ml, p < .05). T cells cocultured with TPT-BMDCs were hyporesponsive in allogeneic mixed lymphocyte reaction. The CD25+foxp3+Treg cell populations increased from 19.9% to 29.7% in the coculture system. Without immunosuppressive therapy, infusion of TPT-BMDCs in recipients before transplantation prolonged rat kidney allograft survival (18.8 ± 1.30 days).

CONCLUSIONS

Our findings demonstrate that TPT inhibits the maturation and allogenicity of BMDCs and promotes the expansion of CD25+foxp3+ regulatory T cells. It suggests that TPT-DCs are potentially useful for preventing kidney transplant rejection.

Triptolide in the treatment of psoriasis and other immune-mediated inflammatory diseases

Apart from cancer chronic (auto)immune-mediated diseases are a major threat for patients and a challenge for physicians. These conditions include classic autoimmune diseases like systemic lupus erythematosus, systemic sclerosis and dermatomyositis and also immune-mediated inflammatory diseases such as rheumatoid arthritis and psoriasis. Traditional therapies for these conditions include unspecific immunosuppressants including steroids and cyclophosphamide, more specific compounds such as ciclosporin or other drugs which are thought to act as immunomodulators (fumarates and intravenous immunoglobulins). With increasing knowledge about the underlying pathomechanisms of the diseases, targeted biologic therapies mainly consisting of anti-cytokine or anti-cytokine receptor agents have been developed. The latter have led to a substantial improvement of the induction of long term remission but drug costs are high and are not affordable in all countries. In China an extract of the herb Tripterygium wilfordii Hook F. (TwHF) is frequently used to treat autoimmune and/or inflammatory diseases due to its favourable cost-benefit ratio. Triptolide has turned out to be the active substance of TwHF extracts and has been shown to exert potent anti-inflammatory and immunosuppressive effects in vitro and in vivo. There is increasing evidence for an immunomodulatory and partly immunosuppressive mechanism of action of triptolide. Thus, compounds such as triptolide or triptolide derivatives may have the potential to be developed as a new class of drugs for these diseases. In this review we summarize the published knowledge regarding clinical use, pharmacokinetics and the possible mode of action of triptolide in the treatment of inflammatory diseases with a particular focus on psoriasis.

Immunosuppressant discovery from Tripterygium wilfordii Hook f: the novel triptolide analog (5R)-5-hydroxytriptolide (LLDT-8)

The Chinese traditional herb Tripterygium wilfordii Hook f (TwHF) has been widely used in the treatment of autoimmune and inflammatory diseases. Over the past few decades, great efforts have been made to explore modern preparations of TwHF with higher efficacy, solubility, and lower toxicity. In this study, we reviewed several examples both of naturally occurring compounds and their derivatives in TwHF, and summarized the preclinical evaluations with regard to autoimmune and inflammatory diseases. All of the candidate compounds described herein have been or are currently in clinical trials. Although some studies encountered problems, the data still provided valuable references for future studies. (5R)-5-hydroxytriptolide (LLDT-8, Leitengshu) is a novel triptolide derivative with potent immunosuppressive and anti-inflammatory activities developed at Shanghai Institute of Materia Medica. Indeed, a Phase I clinical trial for this compound has been completed in rheumatoid arthritis patients. The results will provide the basis for the further exploration of this ancient herb and encourage the research and development of valuable traditional Chinese medicine.

Rapamycin ameliorates dystrophic phenotype in mdx mouse skeletal muscle

Duchenne muscular dystrophy (DMD) is an X-linked, lethal, degenerative disease that results from mutations in the dystrophin gene, causing necrosis and inflammation in skeletal muscle tissue. Treatments that reduce muscle fiber destruction and immune cell infiltration can ameliorate DMD pathology. We treated the mdx mouse, a model for DMD, with the immunosuppressant drug rapamycin (RAPA) both locally and systemically to examine its effects on dystrophic mdx muscles. We observed a significant reduction of muscle fiber necrosis in treated mdx mouse tibialis anterior (TA) and diaphragm (Dia) muscles 6 wks post-treatment. This effect was associated with a significant reduction in infiltration of effector CD4(+) and CD8(+) T cells in skeletal muscle tissue, while Foxp3(+) regulatory T cells were preserved. Because RAPA exerts its effects through the mammalian target of RAPA (mTOR), we studied the activation of mTOR in mdx TA and Dia with and without RAPA treatment. Surprisingly, mTOR activation levels in mdx TA were not different from control C57BL/10 (B10). However, mTOR activation was different in Dia between mdx and B10; mTOR activation levels did not rise between 6 and 12 wks of age in mdx Dia muscle, whereas a rise in mTOR activation level was observed in B10 Dia muscle. Furthermore, mdx Dia, but not TA, muscle mTOR activation was responsive to RAPA treatment.

The effects of immunosuppressive drugs on CD4(+) CD25(+) regulatory T cells: a systematic review of clinical and basic research

OBJECTIVE

To review the effects of different immunosuppressive drugs on proliferation and function of regulatory T cells (Tregs).

METHODS

We searched MEDLINE, Embase (from inception to September 2009), and the Cochrane Library (Issue 4, 2009) for clinical and basic research about the effects of various immunosuppressive drugs on Tregs. Data were extracted and methodological quality was assessed by two independent reviewers. Outcome measures for clinical research included blood Tregs levels, acute rejection episodes, and graft function. Outcomes for basic research included percentage of Tregs proliferation, function, Tregs phenotype, and evidence for possible mechanisms. We analyzed data qualitatively.

RESULTS

Forty-two studies, including 19 clinical trials and 23 basic studies, were included. The immunosuppressive drugs studied were calcineurin inhibitors (CNIs), Rapa, anti-metabolism drugs, IL-2 receptor-blocking antibodies, T-cell depleting antibodies, and co-stimulation blockade antibodies. Most of the studies were on Rapa and CNIs. Eight basic studies on Rapa and CNIs showed that Rapa could promote the proliferation and function of Tregs, while CNIs could not. Five clinical trials involving a total of 158 patients showed that patients taking Rapa had higher blood concentration of Tregs than patients taking CNIs, but no difference was found in graft function (6-42 months follow-up).

CONCLUSION

There is substantial evidence that Rapa favors Tregs survival and function. However, the higher numbers of blood Tregs in patients treated with Rapa do not show any association with better graft function. Larger clinical studies with longer follow-up are needed to more thoroughly assess the efficacy of immunosuppressive drugs on Tregs, and reveal whether a relationship exists between Tregs and graft function.

Triptolide inhibits IL-12/IL-23 expression in APCs via CCAAT/enhancer-binding protein alpha

Triptolide is a biologically active component purified from Chinese herbal plant Tripterygium wilfordii Hook F. It is widely used in East Asia for treatment of systemic lupus erythematosus, rheumatoid arthritis, nephritis, Bechect's disease, psoriasis, atopic dermatitis, and asthma. However, its immunological mechanisms are poorly understood. IL-12 and IL-23 are closely related heterodimeric cytokines that share the common subunit p40. They are produced by APCs and are key factors in the generation and effector functions of Th1 and Th17 cells, respectively. They have been strongly implicated in the pathogenesis of several autoimmune disorders. In this study, we investigated the molecular mechanism whereby triptolide inhibits the expression of the p40 gene in APCs. We demonstrate that triptolide does so at the transcriptional level in part through targeting CCAAT/enhancer-binding protein-alpha (C/EBPalpha), which directly interacts with the p40 promoter and inhibits its transcription in inflammatory macrophages. Triptolide can activate the transcription of C/EBPalpha, and phosphorylation of Ser21 and Thr222/226 critical for C/EBPalpha inhibition of p40. Further, activation of C/EBPalpha by triptolide is dependent on upstream kinases ERK1/2 and Akt-GSK3beta. This study provides mechanistic insights into the immunomodulatory capacity of triptolide and has strong implications for its therapeutic applications in autoimmune diseases.

CCR5 blockade in combination with rapamycin prolongs cardiac allograft survival in mice

Both chemokine receptor 5 (CCR5) blockade and rapamycin (rapa) are effective in modulating transplant immunity and led to prolonged allograft survival, yet a great many grafts were ultimately lost to acute rejection. In this study we examined the inhibition of CCR5 in combination with the treatment with rapa in cardiac transplantation. Fully major histocompatibility complex-mismatched murine cardiac allograft models were randomized to five groups. They were administered with anti-CCR5 antibody or control antibody and rapa or phosphate-buffered saline (PBS), respectively. An additional group was treated with anti-CCR5 antibody, rapa and anti-CD25 antibody. Allograft rejection was investigated by flow cytometric analyses and enzyme-linked immunospot assay. Allografts treated with anti-CCR5 antibody plus rapa showed significantly prolonged survival (83 +/- 3 days, P < 0.001) compared with control antibody plus PBS-treated allografts (6 +/- 1 days). Treatment with anti-CCR5 monoclonal antibody (mAb) plus rapa inhibited significantly the progression of chronic rejction. Further analysis of donor hearts in the anti-CCR5 antibody plus rapa-treated group demonstrated increased infiltration of CD4(+)CD25(+)forkhead box P3(+) regulatory T cells, and depletion of CD25(+) cells resulted in acute rejection of allografts in 18 +/- 1 day. CCR5 blockade in combination with rapa is effective in preventing acute and chronic rejection in a robust murine model. This effect is mediated by CD25(+) T cell recruitment and control of T lymphocyte proliferation.

Triptolide promotes generation of FoxP3+ T regulatory cells in rats

ETHNOPHARMACOLOGICAL RELEVANCE

Triptolide (TPT), a component of the Chinese herb Triptergium wilfordii, has potent immunosuppressive and anti-inflammatory activity and is used clinically in recipients of kidney transplantation.

AIM OF THE STUDY

This work aimed to investigate the effect of TPT on the differentiation of regulatory T lymphocytes (Tregs) from CD4+ cells in rats.

MATERIALS AND METHODS

MACS-purified rat CD4+ cells were costimulated with anti-CD3 and anti-CD28 in the presence of TGF-beta to induce the expression of FoxP3, which was detected by flow cytometry. TPT and cyclosporine A (CsA) were separately added into the cultures to observe the effect on the expression of FoxP3. Kidney transplantation was performed in rats that either received no treatment or were treated with TPT after transplantation.

RESULTS

TPT treatment enhanced the expression of FoxP3 in CD4+ cells, whereas CsA inhibited the FoxP3 expression. In the rat kidney transplantation model, the recipient rats treated with TPT survived longer than the control rats (18-19.83 vs 6.83 days, P<0.05). Meanwhile, the FoxP3+ T cells in the spleens of treated rats were higher than those from the untreated rats (12.4% vs 4.7%, P<0.05).

CONCLUSIONS

These data suggest that TPT may promote the differentiation of CD4+ cells to FoxP3+ Tregs. This would be at least one of the pathways responsible for the immunosuppressive activity of TPT.

Heat Shock Protein 72 Protects Kidney Proximal Tubule Cells From Injury Induced by Triptolide by Means of Activation of the MEK/ERK Pathway

Triptolide, which has been used to treat inflammatory diseases, has also been reported to inhibit proliferation of cancer cells. However, it can cause severe nephrotoxicity, limiting its clinical use. Here, nephrotoxicity of triptolide was observed in vivo and in vitro. Heat shock protein 72 (HSP72) was upregulated during kidney injury in rats. HSP72 partially protected human kidney proximal tubule cell lines HK-2 and HKC from triptolide-induced injury. Phospho-Raf, phospho-MEK and phospho-ERK were elevated in HK-2 cells that overexpressed HSP72 after either heat shock or triptolide treatment, and downregulated when HSP72 was repressed by siRNA. The participation of the MEK/ERK1/2 pathway was confirmed by exposure of the cells to the MEK inhibitor U0126. Collectively, our results suggested that HSP72 plays a protective role by means of the MEK/ERK pathway, against triptolide-induced kidney injury.

Rapamycin-treated mature dendritic cells have a unique cytokine secretion profile and impaired allostimulatory capacity

Rapamycin (RAPA, sirolimus) is a recently introduced immunosuppressive agent. Its effect on the differentiation and antigen uptake of immature dendritic cells (iDCs) has been studied. However, whether it can also modulate the function of mature DCs (mDCs) is unknown. We investigated the effects of RAPA on rat bone marrow-derived DCs at different stages of maturation. RAPA affected maturation, increased apoptosis and reduced lipopolysaccharide (LPS)-induced IL-12 and IL-10 production in iDCs. However, mDCs were resistant to RAPA-induced apoptosis. RAPA-mDCs produced significantly less IL-10 and TNF-alpha when compared with mature DCs but similar amounts of IL-12. RAPA did not affect constitutive NF-kappaB activity, but inhibited allostimulatory activity in mature DCs. In conclusion, mDCs treated with RAPA are reprogrammed to produce a unique cytokine secretion profile and exhibit low allostimulatory capacity, which may play an important role in rapamycin-based immunomodulation.

Immunosuppressive effects of demethylzeylasteral in a rat kidney transplantation model

In this study, we examined the immunosuppressive activity of demethylzeylasteral (T-96), isolated from the traditional Chinese herbal medicine, Tripterygium wilfordii Hook f. Its immunosuppressive effect was investigated using mouse splenocytes in vitro, and in an in vivo rat kidney transplant model. T-96 inhibited mouse splenocyte proliferation in a dose dependent manner. In the rat kidney transplant study, rats were randomly divided into eight groups following kidney transplantation, and different doses of T-96 or cyclosporin A (CsA) were administered to each group. T-96 alone at doses of 10 or 20 mg/kg/day significantly prolonged the survival of kidney-transplanted rats, compared with transplanted but untreated control rats. A combination of T-96 and prednisone also significantly prolonged survival: 10 mg/kg/day T-96 with 10 mg/kg/day prednisone increased the survival time to 31.8+/-6.5 days. Moreover, the combination of T-96 and prednisone was also effective in suppressing rejection of rat transplanted kidneys. These results demonstrate the strong immunosuppressive activity of T-96 and suggest a possible clinical use for T-96 as an immunosuppressive agent in the fields of organ transplantation and autoimmune disorders.