(5R)-5-hydroxytriptolide attenuated collagen-induced arthritis in DBA/1 mice via suppressing interferon-gamma production and its related signaling

Comprehensive transcriptomic analyses identify the immunosuppressive effects of LLDT-8 in ART-treated SIV-infected rhesus macaques

BACKGROUND

Chronic immune activation plays a significant role in the pathogenesis and disease progression of human immunodeficiency virus (HIV), and the existing interventions to address this issue are limited. In a phase II clinical trial, (5R)-5-hydroxytriptolide (LLDT-8) demonstrated promising potential in enhancing CD4+ T cell recovery. However, the therapeutical effects of LLDT-8 remained to be systemic explored.

METHODS

To assess the treatment effects of LLDT-8, we conducted flow cytometry and RNA-seq analyses on eight Chinese rhesus monkeys infected with simian immunodeficiency virus (SIV). Additionally, we performed comprehensive transcriptomic analyses, including cross-sectional and longitudinal differentially expressed gene (DEG) analysis, gene set enrichment analysis (GSEA), weighted gene co-expression network analysis (WGCNA), and deconvolution analysis using peripheral blood mononuclear cell (PBMC) samples from 14-time points. These findings were further validated with RNA-seq analysis on patients who received LLDT-8 treatment, along with in vitro cellular experiments using human PBMCs.

RESULTS

Flow cytometry analysis revealed that LLDT-8 treatment significantly reduced the percentage of HLA-DR+CD38+CD8+ T cells in SIV-infected rhesus monkeys (P < 0.001). The cross-sectional and longitudinal analysis identified 2531 and 1809 DEGs, respectively. GSEA analysis indicated that LLDT-8 treatment led to significant downregulation of proliferation-related pathways, such as E2F targets, G2M checkpoint, and mitotic spindle pathways. WGCNA analysis identified two modules and 202 hub genes associated with CD8 activation levels. Deconvolution analysis showed a significant decrease in the proportion of CD8+ T cells and activated CD4+ T cells during LLDT-8 treatment. Gene ontology results demonstrated that the common DEGs between LLDT-8-treated patients and rhesus monkeys were primarily enriched in cell activation and cell cycle progression. Furthermore, in vitro cellular experiments validated the consistent impact of LLDT-8 in inhibiting proliferation, activation (HLA-DR and CD38 expression), exhaustion (PD-1 expression), and IFN-γ production in human CD4+ and CD8+ T cells.

CONCLUSION

LLDT-8 exhibited notable efficacy in alleviating immune activation in both an in vivo animal model and in vitro human cell experiments. These findings suggest that LLDT-8 may hold potential as a drug for managing systemic immune activation associated with SIV/HIV infection, warranting further prospective clinical exploration.

Efficacy and safety of 5-aminolevulinic acid in adult-onset Still's disease: A preclinical study in mice and a pilot study in humans

The study aimed to investigate the therapeutic effects of 5-aminolevulinic acid/sodium ferrous citrate (5-ALA/SFC) on adult-onset Still's disease (AOSD), specifically focusing on arthritis and macrophage activation syndrome (MAS). We used mouse models to assess the impact of 5-ALA/SFC on collagen-induced arthritis (CIA) and MAS induced by synthetic oligonucleotides containing CpG motifs (CpG-S-ODN). Additionally, we conducted a pilot study with AOSD patients receiving prednisolone (PSL) treatment and 5-ALA/SFC administration to evaluate its efficacy and safety. The 5-ALA/SFC group exhibited significantly lower joint scores in CIA mice. In CpG-S-ODN-treated mice, 5-ALA/SFC administration led to reduced hemophagocytosis and splenomegaly. The anti-inflammatory properties of 5-ALA/SFC were attributed to the suppression of CCL4 and CXCL10 production in monocytes and the induction of M2 macrophages. AOSD patients treated with 5-ALA/SFC demonstrated successful PSL tapering without adverse events. Collectively, the administration of 5-ALA/SFC showed promising potential in ameliorating arthritis and MAS in AOSD patients.

Activities and Molecular Mechanisms of Diterpenes, Diterpenoids, and Their Derivatives in Rheumatoid Arthritis

Diterpenes and their derivatives have many biological activities, including anti-inflammatory and immunomodulatory effects. To date, several diterpenes, diterpenoids, and their laboratory-derived products have been demonstrated for antiarthritic activities. This study summarizes the literature about diterpenes and their derivatives acting against rheumatoid arthritis (RA) depending on the database reports until 31 August 2021. For this, we have conducted an extensive search in databases such as PubMed, Science Direct, Google Scholar, and Clinicaltrials.gov using specific relevant keywords. The search yielded 2708 published records, among which 48 have been included in this study. The findings offer several potential diterpenes and their derivatives as anti-RA in various test models. Among the diterpenes and their derivatives, andrographolide, triptolide, and tanshinone IIA have been found to exhibit anti-RA activity through diverse pathways. In addition, some important derivatives of triptolide and tanshinone IIA have also been shown to have anti-RA effects. Overall, findings suggest that these substances could reduce arthritis score, downregulate oxidative, proinflammatory, and inflammatory biomarkers, modulate various arthritis pathways, and improve joint destruction and clinical arthritic conditions, signs, symptoms, and physical functions in humans and numerous experimental animals, mainly through cytokine and chemokine as well as several physiological protein interaction pathways. Taken all together, diterpenes, diterpenoids, and their derivatives may be promising tools for RA management.

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.

A novel tricyclic BTK inhibitor suppresses B cell responses and osteoclastic bone erosion in rheumatoid arthritis

Rheumatoid arthritis (RA) is characterized by joint leukocyte infiltration, synovial inflammation and bone damage result from osteoclastogenesis. Bruton's tyrosine kinase (BTK) is a key regulator of B cell receptor (BCR) and Fc gamma receptor (FcγR) signaling involved in the pathobiology of RA and other autoimmune disorders. SOMCL-17-016 is a potent and selective tricyclic BTK inhibitor, structurally distinct from other known BTK inhibitors. In present study we investigated the therapeutic efficacy of SOMCL-17-016 in a mouse collagen-induced arthritis (CIA) model and underlying mechanisms. CIA mice were administered SOMCL-17-016 (6.25, 12.5, 25 mg·kg-1·d-1, ig), or ibrutinib (25 mg·kg-1·d-1, ig) or acalabrutinib (25 mg·kg-1·d-1, ig) for 15 days. We showed that oral administration of SOMCL-17-016 dose-dependently ameliorated arthritis severity and bone damage in CIA mice; it displayed a higher in vivo efficacy than ibrutinib and acalabrutinib at the corresponding dosage. We found that SOMCL-17-016 administration dose-dependently inhibited anti-IgM-induced proliferation and activation of B cells from CIA mice, and significantly decreased anti-IgM/anti-CD40-stimulated RANKL expression in memory B cells from RA patients. In RANKL/M-CSF-stimulated RAW264.7 cells, SOMCL-17-016 prevented osteoclast differentiation and abolished RANK-BTK-PLCγ2-NFATc1 signaling. In summary, this study demonstrates that SOMCL-17-016 presents distinguished therapeutic effects in the CIA model. SOMCL-17-016 exerts a dual inhibition of B cell function and osteoclastogenesis, suggesting that it to be a promising drug candidate for RA treatment.

Triptolide analog LLDT-8 ameliorates psoriasis-like dermatitis in BALB/c mice via suppressing the IL-36α signaling pathway

Triptolide has shown a good immunosuppressive effect on autoimmune diseases. However, the toxicity limited its widely clinical practice. In this study, we investigated the effects and underlying mechanisms of (5R)-5-hydroxytriptolide (LLDT-8), a novel triptolide derivative, on a murine psoriasis-like dermatitis model and related cell lines. Here, we showed that LLDT-8 significantly attenuated symptoms of psoriasis-like dermatitis induced by imiquimod (IMQ, a TLR7 agonist) by reducing the psoriasis area and severity index (PASI) score and inflammatory parameters. The action of LLDT-8 was involved in down-regulated interleukin (IL)-36α expression and blocked IL-36α pathway by LC-MS-based label-free quantitative (LFQ) proteomic approach and further experiments. Meanwhile, we observed that LLDT-8 significantly inhibited the expression of IL-36α in R837-treated bone marrow-derived dendritic cells (BMDCs). In conclusion, LLDT-8 notably alleviated IMQ-induced psoriasis-like skin inflammation via suppressing the IL-36α signaling pathway, suggesting LLDT-8 might be a potential drug for the treatment of psoriasis.

Therapeutic Effects of (5R)-5-Hydroxytriptolide on Fibroblast-Like Synoviocytes in Rheumatoid Arthritis via lncRNA WAKMAR2/miR-4478/E2F1/p53 Axis

Rheumatoid arthritis (RA) is an autoimmune disease. Fibroblast-like synoviocytes (FLS) serve a major role in synovial hyperplasia and inflammation in RA. (5R)-5-hydroxytriptolide (LLDT-8), a novel triptolide derivative, shows promising therapeutic effects for RA and is now in phase II clinical trials in China. However, the underlying mechanism of LLDT-8 is still not fully understood. Here, we found that LLDT-8 inhibited proliferation and invasion of RA FLS, as well as the production of cytokines. Microarray data demonstrated that LLDT-8 upregulated the expression of long non-coding RNA (lncRNA) WAKMAR2, which was negatively associated with proliferation and invasion of RA FLS, as well as the production of pro-inflammatory cytokines. Knockdown of WAKMAR2 abolished the inhibitory effects of LLDT-8 on RA FLS. Mechanistically, WAKMAR2 sponged miR-4478, which targeted E2F1 and downstreamed p53 signaling. Rescue experiments indicated that the inhibitory effects of LLDT-8 on RA FLS were dependent on WAKMAR2/miR-4478/E2F1/p53 axis.

Treatment of Neurodegenerative Diseases with Bioactive Components of Tripterygium wilfordii

Tripterygium wilfordii Hook F. (TWHF), a traditional Chinese medicine, has been widely used to treat autoimmune and inflammatory diseases including rheumatoid arthritis, systemic lupus erythematosus and dermatomyositis in China. Recently, studies have demonstrated that the bioactive components of TWHF have effective therapeutic potential for neurodegenerative diseases including Alzheimer's disease, Parkinson's disease and Multiple Sclerosis. In this paper, we summarize the research progress of triptolide and celastrol (the two major TWHF components) as well as their analogues in the treatment of neurodegenerative diseases. In addition, we review and discuss the molecular mechanisms and structure features of those two bioactive TWHF components, highlighting their therapeutic promise in neurodegenerative diseases.

Cervus and cucumis peptides ameliorates bone erosion in experimental arthritis by inhibiting osteoclastogenesis

OBJECTIVE

Rheumatoid arthritis is an autoimmune disease characterised by inflammation and bone loss, leading to joint destruction and deformity. The cervus and cucumis polypeptide (CCP) injection, one of the traditional Chinese medicine injections combined extracts from deer horn and sweet melon seeds, is widely used to treat arthritis and bone fracture in China. The present study investigated the therapeutic efficacy and mechanism of CCP on pathological immune cells and bone homoeostasis in rodent experimental arthritis.

METHODS

The effects of CCP (4 mg/kg and 2 mg/kg) on clinical arthritis symptoms, bone erosion, proinflammatory cytokines and pathological immune cells induced by complete Freund's adjuvant was evaluated in male Sprague-Dawley rats. The impacts of CCP (2 mg/kg) on joint erythema and swelling, production of pathogenic antibodies and the proportion of inflammatory cells were assessed in collagen-induced arthritis (CIA) in DBA/1J mice. Regulation of osteoclastogenesis by CCP was observed in the murine macrophage-like RAW264.7 cells treated with receptor activator of nuclear factor-κB ligand (RANKL) and macrophage colony-stimulating factor (M-CSF).

RESULTS

CCP administration significantly prevented disease progression in both adjuvant-induced arthritis (AIA) rats and CIA mice. The therapeutic benefits were accompanied by reduction of paw oedema, reversed bone destruction, decreased pathological changes and osteoclast numbers in joints in AIA rats, as well as attenuated clinical manifestation and autoantibodies production in CIA mice. Meanwhile, in vitro supplemented of CCP concentration dependently inhibited RANKL/M-CSF-induced osteoclast differentiation, without showing cytotoxicity in RAW264.7 cells. Further, the presence of CCP dampened the augmented downstream signalling transduction as well as activation of osteoclast-specific genes and transcription factors induced by RANKL/M-CSF in RAW264.7 cells.

CONCLUSION

Our study suggested that the therapeutic effects of CCP in experimental arthritis could be attributed to its intervention on RANKL-induced osteoclastogenesis signalling pathway in osteoclast precursor cells.

Dioscin, a Steroidal Saponin Isolated from Dioscorea nipponica, Attenuates Collagen-Induced Arthritis by Inhibiting Th17 Cell Response

Dioscin, a steroidal saponin isolated from Dioscorea nipponica Makino, has previously been shown to possess antiarthritic effects. However, the underlying mechanism is still elusive. Herein, we investigated the therapeutic effects of dioscin on collagen-induced arthritis (CIA) in DBA/1 mice and related mechanism. Cytokine production in CII-specific immune responses were measured by enzyme-linked immunosorbent assay (ELISA); Th17 cell-related gene expression, including IL-17A, ROR[Formula: see text] and IL-23p19, were detected by qPCR analysis; Surface marker, T regulatory (Treg) cells and intracellular cytokines (IL-17A and IFN-[Formula: see text]) were evaluated by flow cytometry. We performed Th17 cell differentiation assay in vitro. Results showed that, in vivo, dioscin treatment significantly reduced the severity of CIA, which was accompanied by decreased Th17 response, but not Th1 and Treg response; dioscin-treated mice also showed lower percentage of CD11b[Formula: see text] Gr-1[Formula: see text] neutrophils; In vitro, dioscin treatment suppressed the differentiation of naive CD4[Formula: see text] T cells into Th17 cell and decreased IL-17A production. Collectively, our results indicate that dioscin exerts antiarthritic effects by inhibiting Th17 cell immune response.

(5R)-5-hydroxytriptolide inhibits the inflammatory cascade reaction in astrocytes

Many studies have shown that (5R)-5-hydroxytriptolide is the optimal modified analogue of triptolide, possessing comparable immunosuppressive activity but much lower cytotoxicity than triptolide. Whether (5R)-5-hydroxytriptolide has preventive effects on neuroinflammation is unclear. This study was designed to pretreat primary astrocytes from the brains of neonatal Sprague-Dawley rats with 20, 100 and 500 nM (5R)-5-hydroxytriptolide for 1 hour before establishing an in vitro neuroinflammation model with 1.0 μg/mL lipopolysaccharide for 24 hours. The generation of nitric oxide was detected by Griess reagents. Astrocyte marker glial fibrillary acidic protein was measured by immunohistochemical staining. The levels of tumor necrosis factor-α and interleukin-1β in the culture supernatant were assayed by enzyme linked immunosorbent assay. Nuclear factor-κB/p65 expression was examined by immunofluorescence staining. The phosphorylation of inhibitor of nuclear factor IκB-α and the location of nuclear factor-κB/P65 were determined using western blot assay. Our data revealed that (5R)-5-hydroxytriptolide inhibited the generation of nitric oxide, tumor necrosis factor-α and interleukin-1β from primary astrocytes activated by lipopolysaccharide, decreased the positive reaction intensity of glial fibrillary acidic protein, reduced the expression of tumor necrosis factor alpha and interleukin-1β in culture supernatant, inhibited the phosphorylation of IκB-α and the translocation of nuclear factor-κB/P65 to the nucleus. These results have confirmed that (5R)-5-hydroxytriptolide inhibits lipopolysaccharide-induced glial inflammatory response and provides cytological experimental data for (5R)-5-hydroxytriptolide in the treatment of neurodegenerative diseases.

The Effect of Triptolide in Rheumatoid Arthritis: From Basic Research towards Clinical Translation

Triptolide (TP), a major extract of the herb Tripterygium wilfordii Hook F (TWHF), has been shown to exert potent pharmacological effects, especially an immunosuppressive effect in the treatment of rheumatoid arthritis (RA). However, its multiorgan toxicity prevents it from being widely used in clinical practice. Recently, several attempts are being performed to reduce TP toxicity. In this review, recent progress in the use of TP for RA, including its pharmacological effects and toxicity, is summarized. Meanwhile, strategies relying on chemical structural modifications, innovative delivery systems, and drug combinations to alleviate the disadvantages of TP are also reviewed. Furthermore, we also discuss the challenges and perspectives in their clinical translation.

(5R)-5-hydroxytriptolide ameliorates anti-glomerular basement membrane glomerulonephritis in NZW mice by regulating Fcγ receptor signaling

(5R)-5-hydroxytriptolide (LLDT-8) is a novel triptolide analog that has been identified as a promising candidate for treating autoimmune diseases and has been shown to be effective in treating murine collagen-induced arthritis and lupus nephritis. In the present study, we investigated the therapeutic effect and possible mechanism of action of LLDT-8 in a murine anti-glomerular basement membrane (GBM) glomerulonephritis model. NZW mice were injected with rabbit anti-GBM serum (500 μL, ip). The mice were orally treated with LLDT-8 (0.125 mg/kg, every other day) or a positive control prednisolone (2 mg/kg every day) for 14 d. Blood and urine samples as well as spleen and kidney tissues were collected for analyses. LLDT-8 treatment did not affect the generation of mouse anti-rabbit antibodies. LLDT-8 significantly reversed established proteinuria, improved renal histopathology and attenuated renal dysfunction in glomerulonephritis mice. Furthermore, LLDT-8 inhibited inflammation in the kidney evidenced by significantly decreasing C3 and IgG deposition, reducing the levels of the pathogenic cytokines TNF-α, IL-6, IL-17, and IFN-γ, and reducing related chemokine expression and leukocyte infiltration in kidneys. Moreover, LLDT-8 treatment significantly increased the expression of FcγRIIB in the kidney and spleen. In addition, the treatment restored the reduced expression of FcγRIIB on the surface of kidney effector cells, CD11b⁺ cells, and interfered with FcγR-dependent signaling, especially FcγRIIB-mediated downstream kinases, such as BTK. These results demonstrate that LLDT-8 ameliorates anti-GBM glomerulonephritis by regulating the Fcγ receptor signaling.

Critical Role of Hepatic Cyp450s in the Testis-Specific Toxicity of (5R)-5-Hydroxytriptolide in C57BL/6 Mice

Low solubility, tissue accumulation, and toxicity are chief obstacles to developing triptolide derivatives, so a better understanding of the pharmacokinetics and toxicity of triptolide derivatives will help with these limitations. To address this, we studied pharmacokinetics and toxicity of (5R)-5-hydroxytriptolide (LLDT-8), a novel triptolide derivative immunosuppressant in a conditional knockout (KO) mouse model with liver-specific deletion of CYP450 reductase. Compared to wild type (WT) mice, after LLDT-8 treatment, KO mice suffered severe testicular toxicity (decreased testicular weight, spermatocytes apoptosis) unlike WT mice. Moreover, KO mice had greater LLDT-8 exposure as confirmed with elevated AUC and Cmax, increased drug half-life, and greater tissue distribution. γ-H2AX, a marker of meiosis process, its localization and protein level in testis showed a distinct meiosis block induced by LLDT-8. RNA polymerase II (Pol II), an essential factor for RNA storage and synapsis in spermatogenesis, decreased in testes of KO mice after LLDT-8 treatment. Germ-cell line based assays confirmed that LLDT-8 selectively inhibited Pol II in spermatocyte-like cells. Importantly, the analysis of androgen receptor (AR) related genes showed that LLDT-8 did not change AR-related signaling in testes. Thus, hepatic CYP450s were responsible for in vivo metabolism and clearance of LLDT-8 and aggravated testicular injury may be due to increased LLDT-8 exposure in testis and subsequent Pol II reduction.

Ethyl Caffeate Ameliorates Collagen-Induced Arthritis by Suppressing Th1 Immune Response

The present study was designed to assess the antiarthritic potential of ECF in collagen-induced arthritis (CIA) and explore its underlying mechanism. Methods. In vitro, lymphocyte proliferation assay was measured by CCK-8 kit. In vivo, the therapeutic potential of ECF on CIA was investigated; surface marker, Treg cell, and intracellular cytokines (IL-17A and IFN-γ) were detected by flow cytometry. Th1 cell differentiation assay was performed, and mRNA expression in interferon-γ-related signaling was examined by q-PCR analysis. Results. In vitro, ECF markedly inhibited the proliferation of splenocytes in response to ConA and anti-CD3. In vivo, ECF treatment reduced the severity of CIA, inhibited IFN-γ and IL-6 secretion, and decreased the proportion of CD11b+Gr-1+ splenic neutrophil. Meanwhile, ECF treatment significantly inhibited the IFN-γ expression in CD4+T cell without obviously influencing the development of Th17 cells and T regulatory cells. In vitro, ECF suppressed the differentiation of naive CD4+ T cells into Th1. Furthermore, ECF intensely blocked the transcriptional expression in interferon-γ-related signaling, including IFN-γ, T-bet, STAT1, and STAT4. Conclusion. Our results indicated that ECF exerted antiarthritic potential in collagen-induced arthritis by suppressing Th1 immune response and interferon-γ-related signaling.

(5R)-5-hydroxytriptolide ameliorates lupus nephritis in MRL/lpr mice by preventing infiltration of immune cells

(5R)-5-hydroxytriptolide (LLDT-8), a triptolide derivative with low toxicity, was previously reported to have strong immunosuppressive effects both in vitro and in vivo, but it remains unknown whether LLDT-8 has a therapy effect on systemic lupus erythematosus. In this study, we aimed to investigate the therapeutic effects of LLDT-8 on lupus nephritis in MRL/lpr mice, a model of systemic lupus erythematosus. Compared with the vehicle group, different clinical parameters were improved upon LLDT-8 treatment as follows: prolonged life span of mice, decreased proteinuria, downregulated blood urea nitrogen and serum creatinine, reduced glomerular IgG deposits, and ameliorated histopathology. A decreased expression of the inflammatory cytokines IFN-γ, IL-17, IL-6, and TNF-α was also observed in the kidney of LLDT-8 treated MRL/lpr mice. Moreover, infiltration of T cells in the kidney was mitigated after LLDT-8 treatment, corresponding with decreased expression of related chemokines IP-10, Mig, and RANTES in the kidney. The proportion of macrophage and neutrophil cells and related chemokines expression was also reduced in kidneys of LLDT-8-treated mice. In the human proximal tubule epithelial cell line and mouse mesangial cell line, consistent with our in vivo experimental results, LLDT-8 suppressed the expression of related chemokines and IL-6. In summary, LLDT-8 has a therapeutic benefit for lupus nephritis via suppressing chemokine expression and inhibiting immune cell infiltration in kidneys of MRL/lpr mice.

Artemisinin analogue SM934 attenuate collagen-induced arthritis by suppressing T follicular helper cells and T helper 17 cells

SM934 is an artemisinin analogue with immunosuppressive properties and potent therapeutic activity against lupus-like diseases in autoimmune mice. In this report, the therapeutic efficacy and underlying mechanisms of SM934 on rheumatoid arthritis (RA) was investigated using collagen-induced arthritis (CIA) in DBA/1J mice. We demonstrated that SM934 treatment alleviate the severity of arthritis in CIA mice with established manifestations. The therapeutic benefits were associated with ameliorated joint swelling and reduced extent of bone erosion and destruction. Further, administration of SM934 diminished the development of T follicular helper (Tfh) cells and Th17 cells and suppressed the production of pathogenic antibodies, without altering the proportion of germinal center B cells. Ex vivo, SM934 treatment inhibited the bovine type II collagen (CII) induced proliferation and inflammatory cytokines secretion of CII -reactive T cells. In vitro, SM934 impeded the polarization of naïve CD4⁺ T cells into Tfh cells and the expression of its transcript factor Bcl-6. Moreover, SM934 decreased the IL-21-producing CD4⁺ T cells and dampened the IL-21 downstream signaling through STAT3. These finding offered the convincing evidence that artemisinin derivative might attenuate RA by simultaneously interfering with the generation of Tfh cells and Th17 cells as well as the subsequent antibody-mediated immune responses.

(5R)-5-Hydroxytriptolide (LLDT-8) inhibits osteoclastogenesis via RANKL/RANK/OPG signaling pathway

Background

The aim of this study was to investigate the regulative activity of (5R)-5-hydroxytriptolide (LLDT-8) on receptor activator of nuclear factor κ-B ligand (RANKL)/receptor activator of nuclear factor κ-B (RANK)/Osteoprotegerin (OPG) system in rheumatoid arthritis (RA) and its anti-osteoclastogenesis mechanism.

Methods

The expression of OPG, RANK and RANKL in CD3⁺ T leukomonocytes in both peripheral blood and synovial fluid of RA patients was evaluated by flow cytometry. The levels of interleukin (IL) 1β, IL-6, IL-10, IL-21 and IL-23 in the supernatants of peripheral blood mononuclear cells (PBMCs) and synovial fluid mononuclear cells (SFMCs) were assayed by ELISA. Tartaric acid phosphatase (TRAP) staining was used to identify the osteoclast-like cells derived from RAW264.7. Western blotting analysis was used to check the downstream molecules of RANKL.

Results

LLDT-8 increased the rate of OPG expression in CD3⁺ T leukomonocytes in peripheral blood as well as the ratio of OPG/RANKL in both peripheral blood and synovial fluid. LLDT-8 inhibited IL-1β, IL-6, IL-21 and IL-23 secretion, but promoted the secretion of IL-10 in the supernatants of PBMCs and SFMCs. In addition, LLDT-8 decreased the number of TRAP-positive cells derived from RAW264.7 in the presence of RANKL and M-CSF. Furthermore, LLDT-8 also inhibited the expression of p-IκB, a key regulator of RANKL signaling pathway.

Conclusions

LLDT-8 exerts its anti-osteoclastogenesis effect in RA probably through regulating RANKL/RANK/OPG system and its downstream signaling pathway as well as cytokine productions.

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.

Triptolide: structural modifications, structure-activity relationships, bioactivities, clinical development and mechanisms

Triptolide, a principal bioactive ingredient of Tripterygium wilfordii Hook F, has attracted extensive exploration due to its unique structure of a diterpenoid triepoxide and multiple biological activities. This review will focus on the structural modifications, structure-activity relationships, pharmacology, and clinical development of triptolide in the last forty years.

Polymerized-type I collagen induces upregulation of Foxp3-expressing CD4 regulatory T cells and downregulation of IL-17-producing CD4⁺ T cells (Th17) cells in collagen-induced arthritis

Previous studies showed that polymerized-type I collagen (polymerized collagen) exhibits potent immunoregulatory properties. This work evaluated the effect of intramuscular administration of polymerized collagen in early and established collagen-induced arthritis (CIA) in mice and analyzed changes in Th subsets following therapy. Incidence of CIA was of 100% in mice challenged with type II collagen. Clinimorphometric analysis showed a downregulation of inflammation after administration of all treatments (P < 0.05). Histological analysis showed that the CIA-mice group had extensive bone erosion, pannus and severe focal inflammatory infiltrates. In contrast, there was a remarkable reduction in the severity of arthritis in mice under polymerized collagen, methotrexate or methotrexate/polymerized collagen treatment. Polymerized Collagen but not methotrexate induced tissue joint regeneration. Polymerized Collagen and methotrexate/polymerized collagen but not methotrexate alone induces downregulation of CD4⁺/IL17A⁺ T cells and upregulation of Tregs and CD4⁺/IFN-γ⁺ T cells. Thus, Polymerized Collagen could be an effective therapeutic agent in early and established rheumatoid arthritis by exerting downregulation of autoimmune inflammation.

Berberine induces dendritic cell apoptosis and has therapeutic potential for rheumatoid arthritis

OBJECTIVE

To investigate the effects of berberine on dendritic cell (DC) apoptosis and its potential as a therapeutic agent in rheumatoid arthritis (RA).

METHODS

Bone marrow (BM)-derived myeloid DCs (MDCs) and plasmacytoid DCs (PDCs) were generated by culturing BM cells with granulocyte-macrophage colony-stimulating factor/interleukin-4 or flt3L, respectively. Splenic DCs, T cells, and B cells were purified using a magnetic-activated cell sorting system. In vitro apoptosis was assessed by annexin V/propidium iodide or Hoechst 33258 staining. The in vivo effects of berberine were examined in mice with collagen-induced arthritis (CIA). Immune responses against type II collagen (CII) were determined by assaying serum antibody levels, lymphocyte proliferation, and cytokine production. The proportions of DCs and apoptosis of different immune cell subsets in spleens and lymph nodes were analyzed by flow cytometry and immunohistochemistry after subset-specific surface marker labeling and TUNEL staining.

RESULTS

Exposure of MDCs to berberine during BM cell differentiation reduced cell recovery by inducing apoptosis. Sensitivity to berberine-induced apoptosis was acquired starting on day 3 of DC differentiation, and mature DCs were more sensitive to berberine than immature DCs. Murine peritoneal macrophages, RAW 264.7 cells, and Jurkat cells were insensitive to berberine-induced apoptosis. Splenic DCs were more sensitive to berberine than T and B cells. Susceptibility of PDCs to berberine-induced apoptosis was similar to that of MDCs. In mice with CIA, berberine treatment ameliorated arthritis, suppressed CII-specific immune responses, and selectively increased the incidence of apoptosis in DCs within spleens and lymph nodes.

CONCLUSION

These findings show that berberine selectively induces apoptosis in DCs. Berberine may thus represent a novel therapeutic agent for RA.

(5R)-5-hydroxytriptolide inhibits the immune response of human peripheral blood mononuclear cells

AIM

(5R)-5-hydroxytriptolide (LLDT-8) displayed immunosuppressive activities both in vitro and in autoimmune disease models. Here, we aim to further clarify the effect of LLDT-8 on the immune responses of human peripheral blood mononuclear cells (PBMC).

METHOD

Cell proliferation of human PBMC from healthy donors was evaluated by [3H]-thymidine uptake. NK cell cytotoxicity was assayed using K562 cells in a [3H] lysis assay. Cytokine production was determined by enzyme-linked immunosorbent assay. The expression of cell surface molecules was detected with flow cytometry. The mRNA expression and the protein phosphorylation levels were detected by RT-PCR and Western immunoblot assay.

RESULTS

LLDT-8 at 25 and 50 nM significantly inhibited the PHA- and recall antigens-induced T cell proliferation, and suppressed mixed lymphocyte reaction. LLDT-8 reduced cytokines production (IFN-gamma, IL-2, TNF-alpha) in PHA- and Sac-activated PBMC. LLDT-8 did not alter the increased expression of MHC class I/II and B7.1, but reduced B7.2 by approximately 30%. No effect of LLDT-8 was observed for the expression of T cell activation markers (CD69, CD154). However, LLDT-8 significantly reduced IFN-gamma-expressing T cell percentages and IFN-gamma mRNA transcription in PHA-activated T cells. It also inhibited the phosphorylation levels of JNK and p38. LLDT-8 did not affect NK cytotoxic activity against K562 cells.

CONCLUSION

LLDT-8 was a promising immunosuppressant for human immune-related diseases.

Effect of sinomenine on collagen-induced arthritis in mice

The present study was designed to investigate the effect of sinomenine (SIN), an alkaloid extracted from sinomenium acutum on collagen-induced arthritis (CIA) in mice. For this investigation, mice were s.c. immunized with type II collagen (CII) emulsified with complete Freund's adjuvant (day 0). Varying doses of SIN were orally administered daily commencing on day 0 daily over a period of 55 days. The severity of arthritis was evaluated according to clinical score, the effect of SIN on immune responses were determined by measurement of proliferative responses of spleen cells, antibody levels in serum and cytokine assays. Anti-CII IgG2a and IFN-gamma were measured as indicators of Th1 immune responses and anti-CII IgG1, IgE and IL-5 as those of Th2 responses. IL-10 and TGF-beta were measured as indicators of T cell regulator responses. The results showed that treatment with SIN was followed by decreases in the incidence and severity of CIA, anti-CII IgG and the antigen-specific splenocyte proliferation. Production of all isotypes of antibodies including anti-CII IgG2a, IgG1 and IgE as well as secretion of cytokines such as IFN-gamma and IL-5 were suppressed by SIN. In addition, SIN enhanced the secretion of TGF-beta while it had no obvious effect on production of IL-10. These results suggest that the anti-arthritic effect of SIN may be related to the suppression of both Th1 and Th2 immune responses. TGF-beta may at least in part contribute to the suppression of Th1 as well as Th2 immune responses.

The new water-soluble artemisinin derivative SM905 ameliorates collagen-induced arthritis by suppression of inflammatory and Th17 responses

BACKGROUND AND PURPOSE

Our previous study showed that SM905, a novel artemisinin derivative, exhibited potent immunosuppressive activity. In this study, we evaluate preventive and therapeutic effect of SM905 on collagen-induced arthritis (CIA) in DBA/1 mice, and investigate its mechanisms both in inflammatory and autoimmune aspects of the disease.

EXPERIMENTAL APPROACH

CIA was induced by type II bovine collagen (CII) in DBA/1 mice. SM905 was given orally either before (continuously 1 day before booster immunization) or after disease onset (continuously 14 days after booster immunization). Disease incidence and severity were monitored, mRNA expression of proinflammatory mediators was determined by real-time PCR, purified T cell proliferation was assessed using [(3)H]-thymidine incorporated assay, and T helper (Th) 17/Th1/Th2 type cytokine production was examined by ELISA.

KEY RESULTS

Oral treatment with SM905 delayed disease onset, reduced arthritis incidence and severity, and suppressed the enhanced expression of pro-inflammatory cytokines, chemokines and chemokine receptors in draining lymph nodes. The CII-induced T cell proliferation and production of interleukin (IL)-17A by T cells were strikingly inhibited. Correspondingly, the mRNA expression of IL-17A and RORgamma t (a specific transcription factor for Th17) was also reduced. This effect was coupled with a striking reduction of IL-6 production, which has a critical role in Th17 development. In established arthritis, SM905 profoundly inhibited disease progression, reduced IL-17A and RORgamma t mRNA expression, and suppressed pro-inflammatory mediator expression in arthritic joints.

CONCLUSIONS AND IMPLICATIONS

SM905 had beneficial effects on CIA by suppressing inflammatory and pathogenic Th17 responses.

(5R)-5-hydroxytriptolide (LLDT-8) protects against bleomycin-induced lung fibrosis in mice

AIM

To study the protective effects of a triptolide-derived, novel compound, (5R)-5-hydroxytriptolide (LLDT-8), on bleomycin-induced lung fibrosis.

METHODS

C57BL/6 mice received an intratracheal injection of bleomycin and were then treated with LLDT-8 (0.5, 1, 2 mg/kg, ip) once daily for 7 or 14 consecutive days. The body weight loss and lung index augmentation was observed; the inflammatory response including differential cells counts of neutrophils, macrophages, and lymphocytes in the bronchoalveolar lavage fluid (BALF), superoxide dismutase (SOD), and malondialdehyde (MDA) level in the lung homogenates was detected, and the fibrosis extent was evaluated by hydroxyproline content and histopathological changes in the lungs. In addition, the pro-inflammatory and pro-fibrotic cytokines, tumor necrosis factor-alpha (TNF-alpha), interleukin-4 (IL-4), and transforming growth factor-alpha (TGF-alpha) production in the lungs were measured.

RESULTS

LLDT-8 alleviated the body weight loss and lung index increase caused by bleomycin, reduced neutrophils and lymphocytes in the BALF, promoted SOD activity, decreased MDA production, and inhibited the hydroxyproline level and the amelioration of lung tissue histological damage. Moreover, LLDT-8 suppressed TNF-alpha, IL-4, and TGF-beta production in the lung homogenates.

CONCLUSION

LLDT-8 showed protective effects against bleomycin-induced lung fibrosis, and the results suggested the potential role of LLDT-8 in the treatment of this disease.

Suppressive effect of a novel water-soluble artemisinin derivative SM905 on T cell activation and proliferation in vitro and in vivo

Artemisinin and its derivatives exhibit potent immunosuppressive activity. The aim of this study was to investigate the suppressive effects of SM905, a new water-soluble artemisinin derivative, on T lymphocytes both in vitro and in vivo, and explore its potential mode of action. The results showed that SM905 had a high inhibitory activity in Concanavalin A (ConA)-induced splenocyte proliferation and mixed lymphocyte reaction, and a relatively low cytotoxicity in vitro. In ovalbumin-immunized mice, oral administration of SM905 dose-dependently suppressed T cell proliferative response to ovalbumin, and inhibited anti-ovalbumin interleukin-2 (IL-2) and interferon-gamma (IFN-gamma) production by T cells. Further studies showed that SM905 inhibited TCR (T cell receptor)/CD3 plus CD28-mediated primary T cell proliferation and cytokine production (IL-2 and IFN-gamma), and exerted an inhibitory action on the phosphorylation of mitogen-activated protein (MAP) kinases including extracellular signal-regulated kinase (ERK), p38 and Jun N-terminal kinase (JNK), and the activation of Ras. The results of this study provided experimental evidence that the new artemisinin derivative SM905 had immunosuppressive effects both in vitro and in vivo. SM905 suppressed T cell activation, which was associated with the inhibition of MAP kinases and Ras activation. Our results suggested a potential of SM905 to be developed as a new type agent for treating T cell-mediated immune disorder.

(5R)-5-hydroxytriptolide inhibits IFN-gamma-related signaling

AIM

(5R)-5-hydroxytriptolide (LLDT-8) displayed anti-arthritis and anti-allogenic transplantation rejection activities in our previous studies. Here, we aim to further clarify the effect of LLDT-8 on the pro-inflammatory cytokine IFN-gamma.

METHODS

T cells were activated with anti-CD3 antibody or concanavalin A (ConA). The expression of cell surface molecules was detected with flow cytometry. Cells were labeled with carboxyfluorescein diacetate succinimidyl ester (CFSE) to test cell division. IFN-gamma production was determined by enzyme-linked immunosorbent assay. Cell proliferation was evaluated by [3H]-thymidine uptake. Mice were immunized with ovalbumin to assess the in vivo immune response. RT-PCR and Real-time PCR were applied to determine the mRNA expression. The protein phosphorylation levels were detected by Western immunoblot assay.

RESULTS

LLDT-8 at 100 nmol/L did not change the CD25, CD69, and CD154 expressions in anti-CD3-stimulated T cells. LLDT-8 markedly blocked the cell division of CD4 and CD8 T cells after ConA stimulation. LLDT-8 inhibited T cell-derived IFN-gamma production. Moreover, LLDT-8 suppressed the ovalbumin-specific T cell proliferation and IFN-gamma generation. In anti-CD3-activated T cells, LLDT-8 abrogated the mRNA expression of signal transducer and activator of transcription1 (STAT1), T-box transcription factor, IL-12 receptor beta2, STAT4, and interferon regulatory factor 1 in the IFN-gamma expression pathway. Western blot analysis showed that LLDT-8 blocked the phosphorylation levels of extracellular signal-regulated kinase, stress-activated protein kinase (SAPK)/c-Jun N-terminal kinase, and p38 mitogen-activated protein kinase in anti-CD3 plus anti-CD28-activated T cells. In addition, LLDT-8 reduced the transcripts of macrophage inflammatory protein (Mip)-1alpha, Mip-1beta, regulated upon activation normally T-cell expressed and secreted, inducible protein-10, IFN-inducible T cell a chemoattractant, and monokine induced by IFN-gamma in IFN-gamma-stimulated murine macrophage cell line Raw 264.7 cells.

CONCLUSION

LLDT-8 was a potential inhibitor for IFN-gamma-associated signaling.