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

Tripterygium wilfordii Hook. F. and Its Extracts for Psoriasis: Efficacy and Mechanism

Psoriasis is an inflammatory autoimmune skin condition that is clinically marked by chronic erythema and scaling. The traditional Chinese herb Tripterygium wilfordii Hook. F. (TwHF) is commonly used in the treatment of immune-related skin illnesses, such as psoriasis. In clinical studies, PASI (Psoriasis Area and Severity Index) were dramatically decreased by TwHF and its extracts. Their benefits for psoriasis also include relief from psoriasis symptoms such as itching, dryness, overall lesion scores and quality of life. And the pathological mechanisms include anti-inflammation, immunomodulation and potentially signaling pathway modulations, which are achieved by modulating type-3 inflammatory cytokines including IL-22, IL-23, and IL-17 as well as immune cells like Th17 lymphocytes, γδT cells, and interfering with IFN-SOCS1, NF-κB and IL- 36α signaling pathways. TwHF and its extracts may cause various adverse drug reactions, such as gastrointestinal responses, aberrant hepatocytes, reproductive issues, and liver function impairment, but at adequate doses, they are regarded as an alternative therapy for the treatment of psoriasis. In this review, the effectiveness and mechanisms of TwHF and its extracts in psoriasis treatment are elucidated.

A comprehensive review of Tripterygium wilfordii hook. f. in the treatment of rheumatic and autoimmune diseases: Bioactive compounds, mechanisms of action, and future directions

Rheumatic and autoimmune diseases are a group of immune system-related disorders wherein the immune system mistakenly attacks and damages the body's tissues and organs. This excessive immune response leads to inflammation, tissue damage, and functional impairment. Therapeutic approaches typically involve medications that regulate immune responses, reduce inflammation, alleviate symptoms, and target specific damaged organs. Tripterygium wilfordii Hook. f., a traditional Chinese medicinal plant, has been widely studied in recent years for its application in the treatment of autoimmune diseases, including rheumatoid arthritis, systemic lupus erythematosus, and multiple sclerosis. Numerous studies have shown that preparations of Tripterygium wilfordii have anti-inflammatory, immunomodulatory, and immunosuppressive effects, which effectively improve the symptoms and quality of life of patients with autoimmune diseases, whereas the active metabolites of T. wilfordii have been demonstrated to inhibit immune cell activation, regulate the production of inflammatory factors, and modulate the immune system. However, although these effects contribute to reductions in inflammatory responses and the suppression of autoimmune reactions, as well as minimize tissue and organ damage, the underlying mechanisms of action require further investigation. Moreover, despite the efficacy of T. wilfordii in the treatment of autoimmune diseases, its toxicity and side effects, including its potential hepatotoxicity and nephrotoxicity, warrant a thorough assessment. Furthermore, to maximize the therapeutic benefits of this plant in the treatment of autoimmune diseases and enable more patients to utilize these benefits, efforts should be made to strengthen the regulation and standardized use of T. wilfordii.

An optimized cocktail of small molecule inhibitors promotes the maturation of dendritic cells in GM-CSF mouse bone marrow culture

Dendritic cells (DCs) are the most potent antigen-presenting cells, playing an essential role in the pathogen and tumor recognition, and anti-tumor immunity, and linking both the innate and adaptive immunity. The monocyte-derived DCs generated by ex vivo culture, have been used for cancer immunotherapy to eliminate tumor; however, the clinical efficacies are not sufficient, and further improvement is essential. In this study, we established a method to generate DCs using small molecule compounds for cancer immunotherapy. We observed an increase in the percentage of CD11c+I-A/I-Ehigh cells, representing DCs, by adding four small molecular inhibitors: Y27632, PD0325901, PD173074, and PD98059 (abbreviated as YPPP), in mouse bone marrow (BM) culture with granulocyte-macrophage colony stimulating factor (GM-CSF). BM-derived DCs cultured with YPPP (YPPP-DCs) showed high responsiveness to lipopolysaccharide stimulation, resulting in increased interleukin (IL) -12 production and enhanced proliferation activity when co-cultured with naïve T cells compared with the vehicle control. RNA-seq analysis revealed an upregulation of peroxisome proliferator - activated receptor (PPAR) γ associated genes increased in YPPP-DCs. In tumor models treated with anti-programmed death (PD) -1 therapies, mice injected intratumorally with YPPP-DCs as a DCs vaccine exhibited reduced tumor growth and increased survival. These findings suggested that our method would be useful for the induction of DCs that efficiently activate effector T cells for cancer immunotherapy.

The Effects of Nebulized Inhaled Triptolide on Airway Inflammation in a Mouse Model of Asthma

Inhalation of nebulized TP has received little attention in the past. Here, we intend to investigate the effect of nebulized inhaled TP on airway inflammation in a mouse model of asthma. 29 SPF BALB/c mice were divided into four groups: blank control (Blk, n = 5), normal saline (NS, n = 8), dexamethasone (Dex, n = 8), and TP (n = 8). During the process of sensitization, mice in the three intervention groups were treated with nebulized NS, an injection of Dex, and nebulized triptolide, respectively. Then bronchoalveolar lavage fluid (BALF), peripheral blood, and lung tissue were collected. Relevant cytokines, transcriptional factors, and CD4+Th17+ T cell proportions were assessed and compared. IL-6, IL-17, IL-23, and TGF-β1 demonstrated a significant difference between groups in the following order: Dex < TP < NS (P ≤ 0.001), while IL-10 changed in the opposite direction (P < 0.001). At the transcriptional level in lung tissue, the Ct value of IL-17 in the Dex group was significantly higher than in the NS and TP groups (P < 0.001). Meanwhile, it was higher in the TP group than in the NS group (P < 0.001). The Ct value of RORγt demonstrated a significant difference among three groups in the following order: Dex > TP > NS (P < 0.001). An opposite trend of FoxP3 Ct value was revealed in the order: NS > TP > Dex. The proportion of CD4+Th17+ cells was 9.53 ± 2.74% in the NS group, 4.23 ± 2.26% in the Dex group, and 6.76 ± 2.99% in the TP group, which shows significant differences between the NS and Dex (P < 0.001) or NS and TP groups (P < 0.05). Inhalation of nebulized triptolide can play a role in suppressing airway inflammation with inflammatory cytokines and transcriptional factors reduced and CD4+Th17+ T cells dampened, also in a manner less than injected dexamethasone.

Mechanism for the therapeutic effect of Tripterygium wilfordii Hook. f. preparations on IgA nephropathy

Tripterygium wilfordii Hook. f. is a traditional Chinese herbal medicine. The bioactive compounds from Tripterygium wilfordii Hook. f. have unique immunosuppressive and anti-inflammatory effects, and can exert their pharmacological effects through multi-target and multi-channel. Tripterygium wilfordii Hook. f. preparations have been used in IgA nephropathy (IgAN) for many years and are well accepted for good curative effects. However, the underlying mechanisms are still unclear. It is valuable to summarize the current progress in clinical application of Tripterygium wilfordii Hook. f. preparations in IgAN and other kidney diseases. We discussed the component characteristics, efficacies in reducing urinary protein levels and protecting renal function, as well as the side effects. As for the mechanisms, we should focus on all links of IgAN pathogenesis, including reducing the production of pathogenic IgA, decreasing renal inflammation and fibrosis, and protecting podocytes. As a representative drugs with clear efficacy and potential toxicity, Tripterygium wilfordii Hook. f. preparations need more in-depth basic and clinical research to improve their efficacy and safety.

Medicinal Plant Extracts and Natural Compounds for the Treatment of Cutaneous Lupus Erythematosus: A Systematic Review

Cutaneous lupus erythematosus (CLE) is a group of autoimmune connective tissue disorders that significantly impact quality of life. Current treatment approaches typically use antimalarial medications, though patients may become recalcitrant. Other treatment options include general immunosuppressants, highlighting the need for more and more targeted treatment options. The purpose of this systematic review was to identify potential compounds that could be repurposed for CLE from natural products since many rheumatologic drugs are derived from natural products, including antimalarials. This study was registered with PROSPERO, the international prospective register of systematic reviews (registration number CRD42021251048). We comprehensively searched Ovid Medline, Cochrane Library, and Scopus databases from inception to April 27th, 2021. These terms included cutaneous lupus erythematosus; general plant, fungus, bacteria terminology; selected plants and plant-derived products; selected antimalarials; and JAK inhibitors. Our search yielded 13,970 studies, of which 1,362 were duplicates. We screened 12,608 abstracts, found 12,043 to be irrelevant, and assessed 565 full-text studies for eligibility. Of these, 506 were excluded, and 59 studies were included in the data extraction. The ROBINS-I risk of bias assessment tool was used to assess studies that met our inclusion criteria. According to our findings, several natural compounds do reduce inflammation in lupus and other autoimmune skin diseases in studies using in vitro methods, mouse models, and clinical observational studies, along with a few randomized clinical trials. Our study has cataloged evidence in support of potential natural compounds and plant extracts that could serve as novel sources of active ingredients for the treatment of CLE. It is imperative that further studies in mice and humans are conducted to validate these findings.

Systematic Review Registration:https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=251048.

Dendritic cell combination therapy reduces the toxicity of triptolide and ameliorates colitis in murine models

Triptolide (TP) exerts a promising effect in the treatment of ulcerative colitis (UC). However, its toxicity seriously hinders its application in the clinic. Previous studies indicated that dendritic cells (DCs) are the main target through which TP exerts its immunoregulatory effect. Thus, we designed an approach to target DCs in vitro to avoid the direct exposure of organs to TP. Our results revealed that DCs pretreated with TP (DCTP) exerted satisfactory therapeutic effects in mice with colitis, resulting in improved colonic inflammation and alleviated local lesion damage. In addition, no obvious toxicity was observed. DCTP also reshaped the immune milieu by decreasing CD4⁺ T cell numbers and increasing regulatory T cell numbers in the spleen, mesenteric lymph nodes, peripheral blood and colon; these effects were further confirmed in vitro. Downregulation of CD80/86, ICAM-1, MHCI, TLR2/4, TNF-α, and IL-6 expression and upregulation of programmed cell death ligand 1 (PDL1) and IL-10 expression were observed, indicating that DCs were converted into tolerogenic DCs. In conclusion, DCTP can effectively reduce toxicity and alleviate colonic inflammation and local lesion damage in mice with colitis. The immune mechanism underlying the effects of DCTP included the conversion of DCs into tolerogenic DCs and the alteration of T cell differentiation to produce immunoinhibitory rather than immunostimulatory T cells.

Therapeutic potential of triptolide in autoimmune diseases and strategies to reduce its toxicity

With the increasing epidemiology of autoimmune disease worldwide, there is an urgent need for effective drugs with low cost in clinical treatment. Triptolide, the most potent bioactive compound from traditional Chinese herb Tripterygium Wilfordii Hook F, possesses immunosuppression and anti-inflammatory activity. It is a potential drug for the treatment of various autoimmune diseases, but its clinical application is still restricted due to severe toxicity. In this review, the pharmacodynamic effects and pharmacological mechanisms of triptolide in autoimmune diseases are summarized. Triptolide exerts therapeutic effect by regulating the function of immune cells and the expression of cytokines through inflammatory signaling pathways, as well as maintaining redox balance and gut microbiota homeostasis. Meanwhile, the research progress on toxicity of triptolide to liver, kidney, reproductive system, heart, spleen, lung and gastrointestinal tract has been systematically reviewed. In vivo experiments on different animals and clinical trials demonstrate the dose- and time- dependent toxicity of triptolide through different administration routes. Furthermore, we focus on the strategies to reduce toxicity of triptolide, including chemical structural modification, novel drug delivery systems, and combination pharmacotherapy. This review aims to reveal the potential therapeutic prospect and limitations of triptolide in treating autoimmune diseases, thus providing guiding suggestions for further study and promoting its clinical translation.

Full spectrum of clonal haematopoiesis-driver mutations in chronic heart failure and their associations with mortality

Aims

Somatic mutations in haematopoietic stem cells can lead to the clonal expansion of mutated blood cells, known as clonal haematopoiesis (CH). Mutations in the most prevalent driver genes DNMT3A and TET2 with a variant allele frequency (VAF) ≥ 2% have been associated with atherosclerosis and chronic heart failure of ischemic origin (CHF). However, the effects of mutations in other driver genes for CH with low VAF (<2%) on CHF are still unknown.

Methods and results

Therefore, we analysed mononuclear bone marrow and blood cells from 399 CHF patients by deep error‐corrected targeted sequencing of 56 genes and associated mutations with the long‐term mortality in these patients (3.95 years median follow‐up). We detected 1113 mutations with a VAF ≥ 0.5% in 347 of 399 patients, and only 13% had no detectable CH. Despite a high prevalence of mutations in the most frequently mutated genes DNMT3A (165 patients) and TET2 (107 patients), mutations in CBL, CEBPA, EZH2, GNB1, PHF6, SMC1A, and SRSF2 were associated with increased death compared with the average death rate of all patients. To avoid confounding effects, we excluded patients with DNMT3A‐related, TET2‐related, and other clonal haematopoiesis of indeterminate potential (CHIP)‐related mutations with a VAF ≥ 2% for further analyses. Kaplan–Meier survival analyses revealed a significantly higher mortality in patients with mutations in either of the seven genes (53 patients), combined as the CH‐risk gene set for CHF. Baseline patient characteristics showed no significant differences in any parameter including patient age, confounding diseases, severity of CHF, or blood cell parameters except for a reduced number of platelets in patients with mutations in the risk gene set in comparison with patients without. However, carrying a mutation in any of the risk genes remained significant after multivariate cox regression analysis (hazard ratio, 3.1; 95% confidence interval, 1.8–5.4; P < 0.001), whereas platelet numbers did not.

Conclusions

Somatic mutations with low VAF in a distinct set of genes, namely, in CBL, CEBPA, EZH2, GNB1, PHF6, SMC1A, and SRSF2, are significantly associated with mortality in CHF, independently of the most prevalent CHIP‐mutations in DNMT3A and TET2. Mutations in these genes are prevalent in young CHF patients and comprise an independent risk factor for the outcome of CHF, potentially providing a novel tool for risk assessment in CHF.

Capping protein regulator and myosin 1 linker 3 regulates transcription of key cytokines in activated phagocytic cells

We have recently reported that capping protein regulator and myosin 1 linker 3 (CARMIL3), first identified as an oncofetal-like gene, is required for metastasis of breast and prostate cancer cells via regulating the actin cytoskeletal dynamics near the plasma membrane. Here, we demonstrate a novel function of CARMIL3 as an essential regulator of the transcription of several key proinflammatory cytokines in macrophages engulfing apoptotic cells and/or exposed to lipopolysaccharides (LPS). CARMIL3-deficient macrophages expressed strongly abrogated levels of interleukin (IL)-6, TNF-α, IL-1β and IL-23 in response to LPS, whereas IL-10 expression was enhanced. An RNA-seq analysis of CARMIL3-deficient and wild-type (WT) RAW264.7 cells stimulated with LPS revealed many differentially expressed genes, impacting several important inflammatory pathways. At the molecular level, CARMIL3 deficiency caused a strong impairment in LPS-activated nuclear factor-κB (NF-κB) signaling with decreased IKKα/β and IκBα phosphorylation and severely reduced p65 protein levels. This study uncovers a crucial role of CARMIL3 in impacting the balance between inflammation and tissue homeostasis via regulating major cytokines production in phagocytic cells.

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

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

Therapeutic targets of thunder god vine (Tripterygium wilfordii hook) in rheumatoid arthritis (Review)

Celastrol and triptolide, chemical compounds isolated from Tripterygium wilfordii hook (also known as thunder god vine), are effective against rheumatoid arthritis (RA). Celastrol targets numerous signaling pathways involving NF‑κB, endoplasmic reticulum Ca2+‑ATPase, myeloid differentiation factor 2, toll‑like receptor 4, pro‑inflammatory chemokines, DNA damage, cell cycle arrest and apoptosis. Triptolide, inhibits NF‑κB, the receptor activator of NF‑κB (RANK)/RANK ligand/osteoprotegerin signaling pathway, cyclooxygenase‑2, matrix metalloproteases and cytokines. The present review examined the chemistry and bioavailability of celastrol and triptolide, and their molecular targets in treating RA. Clinical studies have demonstrated that T. wilfordii has several promising bioactivities, but its multi‑target toxicity has restricted its application. Thus, dosage control and structural modification of T. wilfordii are required to reduce the toxicity. In this review, future directions for research into these promising natural products are discussed.

Prediction of triptolide targets in rheumatoid arthritis using network pharmacology and molecular docking

Network pharmacology is a novel approach that uses bioinformatics to predict and identify multiple drug targets and interactions in disease. Here, we used network pharmacology to investigate the mechanism by which triptolide acts in rheumatoid arthritis (RA). We first searched public databases for genes and proteins known to be associated with RA, as well as those predicted to be targets of triptolide, and then used Ingenuity Pathway Analysis (IPA) to identify enriched gene pathways and networks. Networks and pathways that overlapped between RA-associated proteins and triptolide target proteins were then used to predict candidate protein targets of triptolide in RA. The following proteins were found to occur in both RA-associated networks and triptolide target networks: CD274, RELA, MCL1, MAPK8, CXCL8, STAT1, STAT3, c-JUN, JNK, c-Fos, NF-κB, and TNF-α. Docking studies suggested that triptolide can fit in the binding pocket of the six top candidate triptolide target proteins (CD274, RELA, MCL1, MAPK8, CXCL8 and STAT1). The overlapping pathways were activation of Th1 and Th2 cells, macrophages, fibroblasts and endothelial cells in RA, while the overlapping networks were involved in cellular movement, hematological system development and function, immune cell trafficking, cell-to-cell signaling and interaction, inflammatory response, cellular function and maintenance, and cell death and survival. These results show that network pharmacology can be used to generate hypotheses about how triptolide exerts therapeutic effects in RA. Network pharmacology may be a useful method for characterizing multi-target drugs in complex diseases.

Bioactivity-Guided Isolation and Identification of New and Immunosuppressive Monoterpenoid Indole Alkaloids from Rauvolfia yunnanensis Tsiang

Three new 11-hydroxyburnamine (1) and rauvoyunnanines A-B (2-3), and fourteen known (4-17) monoterpenoid indole alkaloids were isolated from the total alkaloids extract of Rauvolfia yunnanensis, which exhibited promising immunosuppressive activity on T cell proliferation in preliminary screening. Their structures were determined by analysis of high-resolution electrospray ionization mass (HRESIMS), ultraviolet (UV) and nuclear magnetic resonance (NMR) data, and by comparison with the literature. All the alkaloids were evaluated for inhibitory activity on T cell proliferation. Among them, one new compound (1) and reserpine (6) exhibited moderate immunosuppressive activity, with IC50 values of 5.9 μM and 5.0 μM, respectively.

Activation of natural killer T cells contributes to triptolide-induced liver injury in mice

Triptolide (TP) is the main active ingredient of Tripterygium wilfordii Hook.f, which has attracted great interest due to its promising efficacy for autoimmune diseases and tumors. However, severe adverse reactions, especially hepatotoxicity, have restricted its approval in the market. In the present study we explored the role of hepatic natural killer T (NKT) cells in the pathogenesis of TP-induced liver injury in mice. TP (600 μg/kg/day, i.g.) was administered to female mice for 1, 3, or 5 days. We found that administration of TP dose-dependently induced hepatotoxicity, evidenced by the body weight reduction, elevated serum ALT and AST levels, as well as significant histopathological changes in the livers. However, the mice were resistant to the development of TP-induced liver injury when their NKT cells were depleted by injection of anti-NK1.1 mAb (200 μg, i.p.) on days -2 and -1 before TP administration. We further revealed that TP administration activated NKT cells, dominantly releasing Th1 cytokine IFN-γ, recruiting neutrophils and macrophages, and leading to liver damage. After anti-NK1.1 injection, however, the mice mainly secreted Th2 cytokine IL-4 in the livers and exhibited a significantly lower percentage of hepatic infiltrating neutrophils and macrophages upon TP challenge. The activation of NKT cells was associated with the upregulation of Toll-like receptor (TLR) signaling pathway. Collectively, these results demonstrate a novel role of NKT cells contributing to the mechanisms of TP-induced liver injury. More importantly, the regulation of NKT cells may promote effective measures that control drug-induced liver injury.

Immune Homeostasis: Effects of Chinese Herbal Formulae and Herb-Derived Compounds on Allergic Asthma in Different Experimental Models

Allergic asthma is thought to arise from an imbalance of immune regulation, which is characterized by the production of large quantities of IgE antibodies by B cells and a decrease of the interferon-γ/interleukin-4 (Th1/Th2) ratio. Certain immunomodulatory components and Chinese herbal formulae have been used in traditional herbal medicine for thousands of years. However, there are few studies performing evidence-based Chinese medicine (CM) research on the mechanisms and effificacy of these drugs in allergic asthma. This review aims to explore the roles of Chinese herbal formulae and herb-derived compounds in experimental research models of allergic asthma. We screened published modern CM research results on the experimental effects of Chinese herbal formulae and herb-derived bioactive compounds for allergic asthma and their possible underlying mechanisms in English language articles from the PubMed and the Google Scholar databases with the keywords allergic asthma, experimental model and Chinese herbal medicine. We found 22 Chinese herb species and 31 herb-derived anti-asthmatic compounds as well as 12 Chinese herbal formulae which showed a reduction of airway hyperresponsiveness, allergen-specifific immunoglobulin E, inflflammatory cell infifiltration and a regulation of Th1 and Th2 cytokines in vivo, in vitro and ex vivo, respectively. Chinese herbal formulae and herbderived bioactive compounds exhibit immunomodulatory, anti-inflflammatory and anti-asthma activities in different experimental models and their various mechanisms of action are being investigated in modern CM research with genomics, proteomics and metabolomics technologies, which will lead to a new era in the development of new drug discovery for allergic asthma in CM.

Fabrication of a triptolide-loaded and poly-γ-glutamic acid-based amphiphilic nanoparticle for the treatment of rheumatoid arthritis

Triptolide (TP) exhibits immunosuppressive, cartilage-protective and anti-inflammatory effects in rheumatoid arthritis. However, the toxicity of TP limits its widespread use. To decrease the toxic effects, we developed a novel nano-drug carrier system containing TP using poly-γ-glutamic acid-grafted di-tert-butyl L-aspartate hydrochloride (PAT). PAT had an average diameter of 79±18 nm, a narrow polydispersity index (0.18), a strong zeta potential (−32 mV) and a high drug encapsulation efficiency (EE₁=48.6%) and loading capacity (EE₂=19.2%), and exhibited controlled release (t_1/2=29 h). The MTT assay and flow cytometry results indicated that PAT could decrease toxicity and apoptosis induced by free TP on RAW264.7 cells. PAT decreased lipopolysaccharides/interferon γ-induced cytokines expression of macrophage (P<0.05). In vivo, PAT accumulated at inflammatory joints, improved the survival rate and had fewer side effects on tumor necrosis factor α transgenic mice, compared to TP. The blood biochemical indexes revealed that PAT did not cause much damage to the kidney (urea nitrogen and creatinine) and liver (alanine aminotransferase and aspartate aminotransferase). In addition, PAT reduced inflammatory synovial tissue area (P<0.05), cartilage loss (P<0.05), tartrate-resistant acid phosphatase-positive osteoclast area (P<0.05) and bone erosion (P<0.05) in both knee and ankle joints, and showed similar beneficial effect as free TP. In summary, our newly formed nanoparticle, PAT, can reduce the toxicity and guarantee the efficacy of TP, which represents an effective drug candidate for RA with low adverse side effect.

Progranulin Controls Sepsis via C/EBPα-Regulated Il10 Transcription and Ubiquitin Ligase/Proteasome-Mediated Protein Degradation

Progranulin (PGRN) is a widely expressed, pleiotropic protein that is involved in diverse biological processes, including cellular proliferation, neuron development, and wound healing. However, the role of PGRN in the regulation of pathogen-induced systemic inflammation and the mechanisms involved have not been established. In this study, we show that PGRN-deficient mice display heightened mortality in models of polymicrobial sepsis and endotoxinemia, with increased tissue levels of inflammatory cytokines and reduced IL-10 production. Conversely, administration of rPGRN decreases the susceptibility of PGRN-deficient mice to LPS-induced endotoxemic shock and augments IL-10 production by LPS-activated macrophages in a TNFR-dependent manner. Molecular analysis reveals a direct role of the transcription factor C/EBPα in PGRN-regulated IL-10 expression. C/EBPα-deficient macrophages produce less IL-10 in response to LPS. Furthermore, mice deficient in C/EBPα in hematopoietic cells are highly vulnerable to LPS-induced septic shock. Lastly, the defective IL-10 production by PGRN-deficient cells is primarily due to reduced C/EBPα protein stability via the E3 ubiquitin-conjugating enzyme E6AP and proteasome-mediated degradation. To our knowledge, this study provides the first evidence that PGRN is a nonredundant regulator of systemic inflammation via modulating the levels and activity of C/EBPα, IL-10, and the ubiquitin-proteasome proteolysis pathway. The results bear strong and profound implications for PGRN insufficiency and its mutation-associated systemic and organ-specific inflammatory human diseases.

Fabrication of novel vesicles of triptolide for antirheumatoid activity with reduced toxicity in vitro and in vivo

Triptolide (TP) displays a strong immunosuppression function in immune-mediated diseases, especially in the treatment of rheumatoid arthritis. However, in addition to its medical and health-related functions, TP also exhibits diverse pharmacological side effects, for instance, liver and kidney toxicity and myelosuppression. In order to reduce the side effects, a nano drug carrier system (γ-PGA-l-PAE-TP [PPT]), in which TP was loaded by a poly-γ-glutamic acid-grafted l-phenylalanine ethylester copolymer, was developed. PPT was characterized by photon scattering correlation spectroscopy and transmission electron microscopy, which demonstrated that the average diameter of the drug carrier system is 98±15 nm, the polydispersity index is 0.18, the zeta potential is −35 mV, and the TP encapsulation efficiency is 48.6% with a controlled release manner. The methylthiazolyldiphenyl-tetrazolium bromide assay and flow cytometry revealed that PPT could decrease toxicity and apoptosis induced by free TP on RAW264.7 cells, respectively. The detection of reactive oxygen species showed that PPT could decrease the cellular reactive oxygen species induced by TP. Compared with the free TP-treated group, PPT improved the survival rate of the mice (P<0.01) and had no side effects or toxic effects on the thymus index (P>0.05) and spleen index (P>0.05). The blood biochemical indexes revealed that PPT did not cause much damage to the kidney (blood urea nitrogen and creatinine), liver (serum alanine aminotransferase and aspartate aminotransferase), or blood cells (P>0.05). Meanwhile, hematoxylin and eosin staining and terminal-deoxynucleotidyl transferase dUTP nick-end labeling staining indicated that PPT reduced the damage of free TP on the liver, kidney, and spleen. Our results demonstrated that PPT reduced free TP toxicity in vitro and in vivo and that it is a promising fundamental drug delivery system for rheumatoid arthritis treatment.

Immunosuppressive, anti-inflammatory and anti-cancer properties of triptolide: A mini review

OBJECTIVE

Triptolide, the active component of Tripterygium wilfordii Hook F has been used to treat autoimmune and inflammatory conditions for over two hundred years in traditional Chinese medicine. However, the processes through which triptolide exerts immunosuppression and anti-inflammation are not understood well. In this review, we discuss the autoimmune disorders and inflammatory conditions that are currently treated with triptolide. Triptolide also possesses anti-tumorigenic effects. We discuss the toxicity of various triptolide derivatives and offer suggestions to improve its safety. This study also examines the clinical trials that have investigated the efficacy of triptolide. Our aim is to examine the mechanisms that are responsible for the immunosuppressive, anti-inflammatory, and anti-cancer effects of triptolide.

MATERIALS AND METHODS

The present review provides a comprehensive summary of the literature with respect to the immunosuppressive, anti-inflammatory, and anti-cancer properties of triptolide.

RESULTS

Triptolide possesses immunosuppressive, anti-inflammatory, and anti-cancer effects.

CONCLUSION

Triptolide can be used alone or in combination with existing therapeutic modalities as novel treatments for autoimmune disorders, cancers, and for immunosuppression.

The immunoregulatory effects of Chinese herbal medicine on the maturation and function of dendritic cells

ETHNOPHARMACOLOGICAL RELEVANCE

Traditional Chinese herbal medicine (CHM) has a long-history for treatment of various human diseases including tumors, infection, autoimmune diseases in Asian countries, especially in China, Japan, Korea and India. CHM was traditionally used as water extracts and many Chinese herbs were considered to be good for health, which can regulate immune system to protect host from diseases. With the progress of technology, the components of CHM were identified and purified, which included polysaccharides, saponins, phenolic compounds, flavonoids and so on. Recently, accumulating evidence indicates that CHM and its components can regulate immune system through targeting dendritic cells (DCs). We hereby reviewed the immunoregulatory effects of CHM on the maturation, cytokine production and function of DCs. This should help to shed light on the potential mechanism of CHM to improve the usage and clinical efficacy of CHM.

MATERIALS AND METHODS

Literatures about the effects of CHM on DCs were searched in electronic databases such as Pubmed, Google Scholar and Scopus from 2000 to 2014. 'CHM', 'DC' or 'immune' were used as keywords for the searches. We only reviewed literatures published in English.

RESULTS

Over 600 publications were found about 'CHM&immune' and around 120 literatures about 'CHM&DC' were selected and reviewed in this paper. All publications are backed by preclinical or clinical evidences both in vitro and in vivo. Some CHM and its components promote the maturation, pro-inflammatory cytokine production and function of DCs and as the adjuvant enhance immune responses against tumor and infection. In contrast, other CHM and its components suppress the activation status of DCs to induce regulatory T cells, inhibit allergic and inflammatory responses, ameliorate autoimmune diseases, and prolong the allograft survival. A large body of evidence shows that CHM and its components regulate the activation status of DCs through TLRs, NF-κB, MAPK signaling pathways.

CONCLUSION

This review provides useful information for understanding the mechanism of CHM on the treatment of diseases, which facilitates to improve the efficacy of CHM. Based on the immunoregulatory effects of CHM on DCs, it indicated that some CHM and its components could be use to develop adjuvant to enhance antigen-specific immune responses or tolerogenic adjuvant to generate antigen-specific immune tolerance.

A novel crosstalk between TLR4- and NOD2-mediated signaling in the regulation of intestinal inflammation

Although Toll-like receptor 4 (TLR4)- and nucleotide-binding oligomerization domain 2 (NOD2)-mediated signaling mechanisms have been extensively studied individually, the crosstalk between them in the regulation of intestinal mucosal defense and tissue homeostasis has been underappreciated. Here, we uncover some novel activities of NOD2 by gene expression profiling revealing the global nature of the cross-regulation between TLR4- and NOD2-mediated signaling. Specifically, NOD2 is able to sense the intensity of TLR4-mediated signaling, resulting in either synergistic stimulation of Interluekin-12 (IL-12) production when the TLR signaling intensity is low; or in the inhibition of IL-12 synthesis and maintenance of intestinal mucosal homeostasis when the TLR signaling intensifies. This balancing act is mediated through receptor-interacting serine/threonine kinase 2, and the transcriptional regulator CCAAT/enhancer-binding protein α (C/EBPα) via its serine 248 phosphorylation by Protein Kinase C. Mice deficient in C/EBPα in the hematopoietic compartment are highly susceptible to chemically induced experimental colitis in an IL-12-dependent manner. Additionally, in contrast to the dogma, we find that the major Crohn’s disease-associated NOD2 mutations could cause a primarily immunodeficient phenotype by selectively impairing TLR4-mediated IL-12 production and host defense. To restore the impaired homeostasis would be a way forward to developing novel therapeutic strategies for inflammatory bowel diseases.

Triptolide suppresses airway goblet cell hyperplasia and Muc5ac expression via NF-κB in a murine model of asthma

BACKGROUND

We have reported that triptolide inhibited pulmonary inflammation in patients with steroid-resistant asthma. In the present study, we investigated whether suppresses airway remodeling and goblet cell hyperplasia, studied the mechanism of triptolide on mucin5ac (Muc5ac) expression in a murine model of asthma.

METHODS

BALB/c mice were sensitized to intraperitoneal ovalbumin (OVA) followed by repetitive ovalbumin challenge for 6 weeks. Treatments included triptolide (40 μg/kg) and dexamethasone (2mg/kg). The area of bronchial airway (WAt/Pbm), smooth muscle (WAm/Pbm) and mucus index were assessed 24h after the final OVA challenge. Levels of Muc5ac were assessed by ELISA, immunohistology and real-time PCR. Western blot was performed to analyze the phosphorylation of NF-κB p65.

RESULTS

Triptolide and dexamethasone significantly reduced allergen-induced increases in the thickness of bronchial airway, smooth muscle and goblet cell hyperplasia. Levels of lung Muc5ac and Muc5ac mRNA were significantly reduced in mice treated with triptolide and dexamethasone. Phosphorylation of NF-κB p65 was significantly reduced in mice treated with triptolide and dexamethasone.

CONCLUSION

Triptolide may inhibit airway goblet cell hyperplasia and Muc5ac expression in asthmatic mice via NF-κB. It may be a potential drug for the treatment of patients with severe asthma.

Plant components for immune modulation targeting dendritic cells: implication for therapy

Medicinal plant utilization is as old as human life. There are thousands of herbs consumed for medicinal purposes all over the world, especially in east. Their value has not decreased over time and many modern pharmaceuticals have originated from traditional medicinal plants. Studying the reason for their influence is an attractive field of medicine. Among various types of herbs, some function via their immunomodulatory effects. Experiments have shown the regulatory influences of several plants on each type of immune cell, including T cells, B cells, dendritic cells (DCs), macrophages and NK cells. Because of the prominent role of DCs in antigen presentation as the major APC, this review summarizes the immunomodulatory effects of some plants performed through DC effects.

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.

A novel single nucleotide polymorphism in the protein tyrosine phosphatase N22 gene (PTPN22) is associated with Type 1 diabetes in a Chinese population

AIMS

To examine single nucleotide polymorphisms in the protein tyrosine phosphatase N22 gene (PTPN22) and to study their association with Type 1 diabetes in a Chinese cohort.

METHODS

Three hundred and sixty-four young patients with Type 1 diabetes and 719 healthy children were included in this case-controlled study. The genotypes of rs1217385, rs2488457 (-1123C>G), rs1217414, rs1217419, rs3765598 and rs2476601 (1858C>T) in the PTPN22 gene were determined using the SNaPshot method. Alleles, genotypes and haplotype frequencies were compared between patients with Type 1 diabetes and healthy control subjects. The association between single nucleotide polymorphisms and clinical traits/autoantibody status was also analysed.

RESULTS

The single nucleotide polymorphism, rs1217419, located in the second intron of the PTPN22 gene was associated with Type 1 diabetes (odds ratio 1.5, 95% CI 1.14-1.97, P = 0.003). An additional single nucleotide polymorphism, rs1217385, was also associated with Type 1 diabetes; however, the association was secondary to that of rs1217419. The previously reported single nucleotide polymorphism that is associated with Type 1 diabetes (-1123G>C) had only marginal association with Type 1 diabetes in our study. A marginal association was also identified between -1123G>C and glutamic acid decarboxylase autoantibody positivity in patients with Type 1 diabetes. There was no association between the single nucleotide polymorphism 1858C>T and Type 1 diabetes in our studied cohort.

CONCLUSIONS

Our study confirmed that PTPN22 is a gene that contributes to Type 1 diabetes susceptibility. The primary association occurs with single nucleotide polymorphism rs1217419 and there is clear heterogeneity of the association between PTPTN22 polymorphisms and Type 1 diabetes in a Chinese population compared with other populations.

Differential immunomodulatory effects by Tripterygium wilfordii Hook f-derived refined extract PG27 and its purified component PG490 (triptolide) in human peripheral blood T cells: potential therapeutics for arthritis and possible mechanisms explaining in part Chinese herbal theory "Junn-Chenn-Zuou-SS"

Background

For thousands of years, it remains unclear why Chinese prefer complex herbal remedy and seldom try to purify it. One of the reasons is that they believe Chinese herbs compared to Western drugs are relatively less toxic and better tolerated. The so called “Junn-Chenn-Zuou-SS” theory illustrates a concept of coordinated effects from a combination of different Chinese herbs. PG27, a refined extract from a well-known Chinese antirheumatic herb Tripterygium wilfordii Hook f (TwHf), is effective in attenuating transplantation rejection and extending survival of cardiac xenografts.

Methods

Experiments were conducted in human primary T lymphocytes isolated from buffy coat. The activities of the inhibitor of kappaB alpha kinase-inhibitor of kappaB alpha-nuclear factor kappaB (IKK-IκBα-NF-κB) and mitogen activated protein kinase-activator protein-1 (MAPK-AP-1) signaling pathways were determined via electrophoretic mobility shift assays, immunoprecipitation kinase assays, Western blots, and transfection assays.

Results

We showed that PG27 inhibited IKKα-IκBα-NF-κB and MAPK-AP-1 signaling pathways; however, IKKβ activity was less susceptible to inhibition by PG27. In contrast, the purified component of TwHf, PG490 (triptolide), reduced both MAPK-AP-1 and IKK-IκBα-NF-κB signaling pathways, including both IKKα and IKKβ, with similar potency. By means of high performance liquid chromatography analysis, it was estimated that PG490 constituted 1.27 ± 0.06% of the total PG27 content. Further analysis demonstrated that compared to PG490 alone, PG27 that contained an equal amount of PG490 was less toxic and less immunosuppressive, suggesting the presence of cytoprotective ingredient(s) in the non-PG490 components of PG27.

Conclusions

In addition to demonstrating the immunomodulatory capacity of PG27 as the potential therapeutics for arthritis and prevention of transplantation rejection, the differential regulatory effects and mechanisms by PG27 and PG490 further support in part a possibly-existing Chinese herbal theory “Junn-Chenn-Zuou-SS”.

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.

Klf10 inhibits IL-12p40 production in macrophage colony-stimulating factor-induced mouse bone marrow-derived macrophages

Bone marrow-derived macrophages (BMMs) treated with granulocyte-macrophage colony-stimulating factor (GM-CSF) or macrophage colony-stimulating factor (M-CSF), differentiate into GM-CSF-induced mouse bone marrow-derived macrophages (GM-BMMs) or M-CSF-induced mouse bone marrow-derived macrophages (M-BMMs), which have an M1 or M2 profile, respectively. GM-BMMs produce large amounts of proinflammatory cytokines and mediate resistance to pathogens, whereas M-BMMs produce antiinflammatory cytokines that contribute to tissue repair and remodeling. M-BMMs stimulated with lipopolysaccharide (LPS) are in an antiinflammatory state, with an IL-12(low) IL-10(high) phenotype. However, the regulation of this process remains unclear. Klf10 belongs to the family of Krüppel-like transcription factors and was initially described as a TGF-β inducible early gene 1. IL-12p40 is upregulated in LPS-stimulated M-BMMs from Klf10-deficient mice, but downregulated during Klf10 overexpression. Klf11, another member of the Krüppel-like factor family, can also repress the production of IL-12p40. Furthermore, Klf10 binds to the CACCC element of the IL-12p40 promoter and inhibits its transcription. We have therefore identified Klf10 as a transcription factor that regulates the expression of IL-12p40 in M-BMMs.

Prediction of the pharmacokinetic parameters of triptolide in rats based on endogenous molecules in pre-dose baseline serum

Background

Individual variances usually affect drug metabolism and disposition, and hence result in either ineffectiveness or toxicity of a drug. In addition to genetic polymorphism, the multiple confounding factors of lifestyles, such as dietary preferences, contribute partially to individual variances. However, the difficulty of quantifying individual diversity greatly challenges the realization of individualized drug therapy. This study aims at quantitative evaluating the association between individual variances and the pharmacokinetics.

Methodology/Principal Findings

Molecules in pre-dose baseline serum were profiled using gas chromatography mass spectrometry to represent the individual variances of the model rats provided with high fat diets (HFD), routine chows and calorie restricted (CR) chows. Triptolide and its metabolites were determined using high performance liquid chromatography mass spectrometry. Metabonomic and pharmacokinetic data revealed that rats treated with the varied diets had distinctly different metabolic patterns and showed differential C_max values, AUC and drug metabolism after oral administration of triptolide. Rats with fatty chows had the lowest C_max and AUC values and the highest percentage of triptolide metabolic transformation, while rats with CR chows had the highest C_max and AUC values and the least percentage of triptolide transformation. Multivariate linear regression revealed that in baseline serum, the concentrations of creatinine and glutamic acid, which is the precursor of GSH, were linearly negatively correlated to C_max and AUC values. The glutamic acid and creatinine in baseline serum were suggested as the potential markers to represent individual diversity and as predictors of the disposal and pharmacokinetics of triptolide.

Conclusions/Significance

These results highlight the robust potential of metabonomics in characterizing individual variances and identifying relevant markers that have the potential to facilitate individualized drug therapy.

Developing Phytocompounds from Medicinal Plants as Immunomodulators

Imbalance or malfunction of the immune systems is associated with a range of chronic diseases including autoimmune diseases, allergies, cancers and others. Various innate and adaptive immune cells that are integrated in this complex networking system may represent promising targets for developing immunotherapeutics for treating specific immune diseases. A spectrum of phytochemicals have been isolated, characterized and modified for development and use as prevention or treatment of human diseases. Many cytotoxic drugs and antibiotics have been developed from phytocompounds, but the application of traditional or new medicinal plants for use as immunomodulators in treating immune diseases is still relatively limited. In this review, a selected group of medicinal herbs, their derived crude or fractionated phytoextracts and the specific phytochemicals/phytocompounds isolated from them, as well as categorized phytocompound groups with specific chemical structures are discussed in terms of their immunomodulatory bioactivities. We also assess their potential for future development as immunomodulatory or inflammation-regulatory therapeutics or agents. New experimental approaches for evaluating the immunomodulatory activities of candidate phytomedicines are also discussed.

Interleukin-23: a key cytokine in inflammatory diseases

Interleukin-23 (IL-23) is a pro-inflammatory cytokine composed of two subunits, p19 and p40. The p40 subunit is shared with IL-12. IL-23 and IL-12 have different receptors and different effects. Whereas IL-12 induces development of Th1 cells, which produce interferon-γ, IL-23 is involved in differentiation of Th17 cells in a pro-inflammatory context and especially in the presence of TGF-β and IL-6. Activated Th17 cells produce IL-17A, IL-17F, IL-6, IL-22, TNF-α, and GM-CSF. Inflammatory macrophages express IL-23R and are activated by IL-23 to produce IL-1, TNF-α, and IL-23 itself. These effects identify IL-23 as a central cytokine in autoimmunity and a highly promising treatment target for inflammatory diseases. IL-23 is found in the skin of patients with psoriasis, in the bowel wall of patients with chronic inflammatory bowel disease, and in synovial membrane of patients with rheumatoid arthritis. IL-23 is involved in osteoclastogenesis, independently from IL-17, via induction of RANKL expression. Debate continues to surround the role for IL-23 in the pathophysiology of inflammatory joint diseases (rheumatoid arthritis and spondyloarthritis). Ustekinumab, which inhibits IL-12 and IL-23 by blocking p40, has been found effective in cutaneous psoriasis and psoriatic arthritis, as well as in Crohn's disease. Treatments that specifically target IL-23 (antibodies to p19) are being developed.

Morphine withdrawal stress modulates lipopolysaccharide-induced interleukin 12 p40 (IL-12p40) expression by activating extracellular signal-regulated kinase 1/2, which is further potentiated by glucocorticoids

Withdrawal stress is a common occurrence in opioid users, yet very few studies have examined the effects of morphine withdrawal (MW) on immune functioning or the role of glucocorticoids in MW-induced immunomodulation. This study investigated for the first time the role of glucocorticoids in MW modulation of LPS-induced IL-12p40, a key cytokine playing a pivotal role in immunoprotection. Using WT and μ-opioid receptor knock-out mice, we show that MW in vivo significantly attenuated LPS-induced IL-12p40 mRNA and protein expression. The role of glucocorticoids in MW modulation of IL-12p40 was investigated using a murine macrophage cell line, CRL2019, in an in vitro MW model. Interestingly, MW alone in the absence of glucocorticoids resulted in a significant reduction in IL-12p40 promoter activity and mRNA and protein expression. EMSA revealed a concurrent decrease in consensus binding to transcription factors NFκB, Activator Protein-1, and CCAAT/enhancer-binding protein and Western blot analysis demonstrated a significant activation of LPS-induced ERK1/2 phosphorylation. Interestingly, although glucocorticoid treatment alone also modulated these transcription factors and ERK1/2 activation, the addition of glucocorticoids to MW samples resulted in a greater than additive reduction in the transcription factors and significant hyperactivation of LPS-induced ERK1/2 phosphorylation. ERK inhibitors reversed MW and MW plus corticosterone inhibition of LPS-induced IL-12p40. The potentiating effects of glucocorticoids were non-genomic because nuclear translocation of glucocorticoid receptor was not significantly different between MW and corticosterone treatment. This study demonstrates for the first time that MW and glucocorticoids independently modulate IL-12p40 production through a mechanism involving ERK1/2 hyperactivation and that glucocorticoids can significantly augment MW-induced inhibition of IL-12p40.

Inhibition of poly(I:C)-induced matrix metalloproteinase expression in human corneal fibroblasts by triptolide

PURPOSE

Triptolide is a major component of the herb Tripterygium wilfordii Hook f, extracts of which are used in traditional Chinese medicine, and it has been found to possess immunosuppressive and anti-inflammatory properties. Viral infection of the cornea can lead to corneal ulceration and perforation as a result of collagen degradation in the corneal stroma. We have now examined the effect of triptolide on the expression of matrix metalloproteinases (MMPs) induced by polyinosinic-polycytidylic acid [poly(I:C)], a synthetic analog of viral double-stranded RNA, in cultured human corneal fibroblasts.

METHODS

Human corneal fibroblasts were cultured in the absence or presence of poly(I:C) or triptolide. Secretion of MMPs as well as the phosphorylation of mitogen-activated protein kinases (MAPKs) and the NF-κB-inhibitory protein, IκB-α, were examined by immunoblot analysis. The abundance of MMP mRNAs was determined by reverse transcription and real-time polymerase chain reaction analysis.

RESULTS

Poly(I:C) induced the secretion of MMP-1 and MMP-3 from corneal fibroblasts in a concentration-dependent manner as well as increased the intracellular abundance of MMP-1 and MMP-3 mRNAs. Triptolide inhibited these effects of poly(I:C) on MMP expression in a concentration-dependent manner. The poly(I:C)-induced secretion of MMP-1 and MMP-3 was also attenuated by synthetic inhibitors of MAPK and NF-κB signaling pathways. Triptolide inhibited the poly(I:C)-induced phosphorylation of IκB-α but did not affect that of the MAPKs, Extracellular Signal-Regulated Kinase (ERK), p38MAPK, and c-Jun N-Terminal Kinase (JNK).

CONCLUSIONS

Triptolide inhibited the poly(I:C)-induced production of MMP-1 and MMP-3 by human corneal fibroblasts. Triptolide therefore warrants further investigation as a potential treatment for corneal ulceration associated with viral infection.

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.