Recent advances in the pharmacological applications and liver toxicity of triptolide

Triptolide alleviates allergic airway inflammation by inhibiting group 2 innate lymphoid cell function

Group 2 innate lymphoid cells (ILC2s) produce the type 2 cytokines IL-5 and IL-13 and contribute to type 2 immune responses, such as allergic airway inflammation. However, specific drugs, especially traditional Chinese medicines, that target lung ILC2s have rarely been reported. Here, we demonstrate that triptolide ameliorates allergic airway inflammation by suppressing ILC2 activation. IL-33, which is produced mainly by epithelial cells, is the most powerful cytokine for activating ILC2s. Triptolide-treated ILC2s were found to be functionally impaired in response to interleukin (IL)-33 challenge. RNA-seq analysis revealed that triptolide impaired ILC2 function through inflammation-related signalling pathways. ILC2-related genes were up- and down-regulated under the treatment with TPL such as Adrb2, Nmur1, tnfsf11, IL-5, IL-13, IL-9 and so on. Interestingly, we observed not only preventive but also therapeutic effects of triptolide on allergic airway inflammation, indicating that triptolide may serve as a promising traditional Chinese medicine for the treatment of allergic airway inflammation by targeting ILC2s.

Probiotic Limosilactobacillus reuteri DSM 17938 Alleviates Acute Liver Injury by Activating the AMPK Signaling via Gut Microbiota-Derived Propionate

Limosilactobacillus reuteri DSM 17938 (L. reuteri DSM 17938) was one of the most widely used probiotics in humans for gastrointestinal disorders, but few studies have investigated its role in drug-induced liver injury (DILI). Here, we evaluated the efficacy of L. reuteri DSM 17938 using a mouse model of DILI induced by triptolide. Pregavage of L. reuteri DSM 17938 for 1 week remarkably lowered hepatic inflammatory cytokines level and oxidative stress, with diminished serum alanine transaminase and aspartate aminotransferase levels. Metabolomics and RT-qPCR analysis confirmed its ability in ameliorating TP-disrupted hepatic fatty acid β oxidation. Genome annotation of L. reuteri showed its ability to modulate energy metabolism. Targeted metabolomics demonstrated that L. reuteri DSM 17938 modified the short fatty acid profiles in cecum, especially enhancing propionate levels. Further experiments found that L. reuteri DSM 17938 can activate AMPK signaling by upregulating gut microbiota-derived propionate level, thus restoring impaired mitochondrial biogenesis and energy supply processes to recover energy homeostasis, which leads to diminished ROS production and oxidative stress injury in hepatocytes. Besides, AMPK inhibitor dorsomorphin abolished all the effects on propionate protecting mitochondria and energy metabolism. This study established probiotic therapy of L. reuteri DSM 17938 as a preventive intervention for DILI in clinical. We also revealed that L. reuteri DSM 17938 can activate AMPK signaling by propionate, facilitating a deeper understanding of the action mechanism of L. reuteri DSM 17938 against acute liver injury and contributing to the development of its postbiotics and wider applications.

Novel detoxifier of spironolactone against triptolide-induced hepatotoxicity through inhibition of RPB1 degradation

ETHNOPHARMACOLOGICAL RELEVANCE

Triptolide is a major bioactive and toxic ingredient isolated from the traditional Chinese herb Tripterygium wilfordii (T. wilfordii) Hook F. It exhibits potent antitumor, immunosuppressive, and anti-inflammatory biological activities; however, its clinical application is hindered by severe systemic toxicity. Two preparations of T. wilfordii, including T. wilfordii glycoside tablets and T. wilfordii tablets, containing triptolide, are commonly used in clinical practice. However, their adverse side effects, particularly hepatotoxicity, limit their safe use. Therefore, it is crucial to discover potent and specific detoxification medicines for triptolide.

AIM OF THE STUDY

This study aimed to investigate the detoxification effects and potential mechanism of action of spironolactone on triptolide-induced hepatotoxicity to provide a potential detoxifying strategy for triptolide, thereby promoting the safe applications of T. wilfordii preparations in clinical settings.

MATERIALS AND METHODS

Cell viability was assessed using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and crystal violet staining. Nuclear fragmentation was visualized using 4',6-diamidino-2-phenylindole (DAPI) staining, and protein expression was analyzed by Western blotting. The inhibitory effect of spironolactone on triptolide-induced hepatotoxicity was evaluated by examining the effects of spironolactone on serum alanine aminotransferase and aspartate aminotransferase levels, as well as liver pathology in a mouse model of triptolide-induced acute hepatotoxicity. Furthermore, a survival assay was performed to investigate the effects of spironolactone on the survival rate of mice exposed to a lethal dose of triptolide. The effect of spironolactone on triptolide-induced global transcriptional repression was assessed through 5-ethynyl uridine staining.

RESULTS

Triptolide treatment decreased the cell viability, increased the nuclear fragmentation and the cleaved caspase-3 levels in both hepatoma cells and hepatocytes. It also increased the alanine aminotransferase and aspartate aminotransferase levels, induced the hepatocyte swelling and necrosis, and led to seven deaths out of 11 mice. The above effects could be mitigated by pretreatment with spironolactone. Additionally, molecular mechanism exploration unveiled that spironolactone inhibited triptolide-induced DNA-directed RNA polymerase II subunit RPB1 degradation, consequently increased the fluorescence intensity of 5-ethynyl uridine staining for nascent RNA.

CONCLUSIONS

This study shows that spironolactone exhibits a potent detoxification role against triptolide hepatotoxicity, through inhibition of RPB1 degradation induced by triptolide and, in turn, retardation of global transcriptional inhibition in affected cells. These findings suggest a potential detoxification strategy for triptolide that may contribute to the safe use of T. wilfordii preparations.

Tumor Microenvironment Responsive Key Nanomicelles for Effective Against Invasion and Metastasis in Ovarian Cancer Using Mice Model

Background

Ovarian cancer is difficult to detect in its early stages, and it has a high potential for invasion and metastasis, along with a high rate of recurrence. These factors contribute to the poor prognosis and reduced survival times for patients with this disease. The effectiveness of conventional chemoradiotherapy remains limited. Nano-particles, as a novel drug delivery system, have significant potential for improving therapeutic efficacy and overcoming these challenges.

Methods

According to the high expression level of matrix metalloproteinase-2 (MMP-2) in the tumor microenvironment, MMP-2 responsive nano-particles (PVGLIG-MTX-D/T-NMs) containing docetaxel and triptolide were prepared by the thin-film dispersion method. The synergistic effect between docetaxel and triptolide was systematically investigated, the ratio of the two drugs was optimized, and the physicochemical properties of the nano-particles and their ability to inhibit ovarian cancer cell growth and metastasis were evaluated in vitro and in vivo.

Results

PVGLIG-MTX-D/T-NMs enhanced the targeting, stability, and bioavailability of the drug, while reducing the dose and toxicity. In addition, by regulating the expression levels of E-Cadherin, N-Cadherin, matrix metalloproteinases (MMPs), hypoxia-inducible factor 1-alpha (HIF-1α), and vascular endothelial growth factor (VEGF), it exhibited an inhibitory effect on epithelial-mesenchymal transformation (EMT) and tumor cell angiogenesis, and effectively inhibited the invasion and metastasis of ovarian cancer cells.

Conclusion

PVGLIG-MTX-D/T-NMs achieved passive targeting of tumor sites by enhancing permeability and retention (EPR) effects. Subsequently, the uptake of the drug by tumor cells was enhanced by MMP-2 responsiveness and the modification of methotrexate targeting ligands. By regulating the expression levels of invasion- and metastasis-related proteins in tumor tissues, the nano-particles affected the EMT process, inhibited tumor angiogenesis, and suppressed the malignant potential of invasion and metastasis in ovarian cancer. These findings provided a new direction for further exploration of tumor-targeted therapy.

Triptolide exhibits dual anti-tumor effects through inhibiting autophagy and extracellular matrix activation in pancreatic cancer

AIM

The tumor microenvironment in pancreatic cancer, characterized by abundant desmoplastic stroma, has been implicated in the failure of chemotherapy. Therefore, developing therapeutic strategies targeting tumor and stromal cells is essential. Triptolide, a natural compound derived from the plant Tripterygium wilfordii, has shown antitumor activity in various cancers, including pancreatic cancer. However, its effects on pancreatic cancer cells and the microenvironment remain unclear. This study aimed to explore the effect of triptolide on tumor cells and the tumor microenvironment in pancreatic cancer.

METHODS

Cell Counting Kit-8, colony formation, apoptosis, and cell cycle assays were performed to determine the effect of triptolide on tumor cells. Additionally, co-culture assays were performed to explore the effects of the compound on cancer-associated fibroblasts (CAFs) in vitro. Orthotopic xenograft and subcutaneous tumor models were used to explore the antitumor and antistromal activation effects of triptolide in vivo. RNA sequencing was performed to identify the pathways involved in these processes in pancreatic cancer cells.

RESULTS

Triptolide inhibited the proliferation of pancreatic cancer cells and attenuated stromal activation in vitro and in vivo. Furthermore, it suppressed autophagy and induced apoptosis in pancreatic cancer cells by inhibiting the secretion of CXCL1. Extracellular matrix formation in CAFs was disrupted by suppressing the paracrine secretion of TGF-β from tumor cells.

CONCLUSION

These findings indicate that triptolide plays a dual antitumor role against tumor cells and CAFs, thus providing new insights into treating pancreatic cancer in the future.

Sophoricoside reduces inflammation in type II collagen-induced arthritis by downregulating NLRP3 signaling

Immune responses, especially NLRP3 signaling in macrophages, play critical roles in rheumatoid arthritis (RA), an autoimmune and inflammatory disease. In this study, we aimed to identify novel therapies for RA. We focused on sophoricoside (SOP), an isoflavone glycoside isolated from Sophora japonica. We predicted the targets of SOP and performed a Gene Ontology analysis to assess its effects. The results suggested that SOP is related to inflammation regulation. We verified these findings by performing in vitro experiments with M1 macrophages differentiated from human peripheral blood monocytes (THP-1 cells). Sophoricoside administration reduced inflammatory activity and NLRP3, Caspase-1, and IL-1β protein levels in macrophages. In addition, SOP and triptolide (TP) was administered intragastrically to male SD rats (n = 40) in a collagen-induced arthritis model. We observed that SOP and TP reduced the inflammatory responses and symptoms of RA. Moreover, unlike TP, SOP showed no liver or kidney toxicity in rats. In conclusion, SOP reduces inflammation in type II collagen-induced arthritis by downregulating NLRP3 signaling and has potential for future clinical applications as an ideal therapy for RA.

The Yin and Yang of the Natural Product Triptolide and Its Interactions with XPB, an Essential Protein for Gene Expression and DNA Repair

Triptolide, a bioactive diterpene tri-epoxide extracted from Tripterygium wilfordii Hook F (TWHF), exhibits notable pharmacological activities, including anti-inflammatory, immunosuppressive, antifertility, and anticancer effects. Despite its promising therapeutic potential, clinical applications of triptolide are significantly limited by its poor water solubility and substantial toxicity, particularly hepatotoxicity, nephrotoxicity, and cardiotoxicity. These toxic effects are difficult to separate from many of its desired therapeutic effects, the Yin and Yang of triptolide applications. Triptolide's therapeutic and toxic effects are linked to its inhibitory interactions with XPB, a DNA helicase essential for transcription by RNA polymerase II (RNAPII) and nucleotide excision repair (NER). By irreversibly binding to XPB, triptolide inhibits its ATPase activity, leading to global repression of transcription and impaired NER, which underlies its cytotoxic and antitumor properties. Recent developments, including triptolide prodrugs such as Minnelide and derivatives like glutriptolides, aim to enhance its pharmacokinetic properties and reduce toxicity. This review critically examines triptolide's chemical structure, therapeutic applications, toxicological profile, and molecular interactions with XPB and other protein targets to inform future strategies that maximize therapeutic efficacy while minimizing adverse effects.

Lactobacillus rhamnosus GG ameliorates triptolide-induced liver injury through modulation of the bile acid-FXR axis

Triptolide (TP) is the principal bioactive compound of Tripterygium wilfordii with significant anti-tumor, anti-inflammatory and immunosuppressive activities. However, its severe hepatotoxicity greatly limits its clinical use. The underlying mechanism of TP-induced liver damage is still poorly understood. Here, we estimate the role of the gut microbiota in TP hepatotoxicity and investigate the bile acid metabolism mechanisms involved. The results of the antibiotic cocktail (ABX) and fecal microbiota transplantation (FMT) experiment demonstrate the involvement of intestinal flora in TP hepatotoxicity. Moreover, TP treatment significantly perturbed gut microbial composition and reduced the relative abundances of Lactobacillus rhamnosus GG (LGG). Supplementation with LGG reversed TP-induced hepatotoxicity by increasing bile salt hydrolase (BSH) activity and reducing the increased conjugated bile acids (BA). LGG supplementation upregulates hepatic FXR expression and inhibits NLRP3 inflammasome activation in TP-treated mice. In summary, this study found that gut microbiota is involved in TP hepatotoxicity. LGG supplementation protects mice against TP-induced liver damage. The underlying mechanism was associated with the gut microbiota-BA-FXR axis. Therefore, LGG holds the potential to prevent and treat TP hepatotoxicity in the clinic.

Proteasome activity inhibition mediates endoplasmic reticulum stress-apoptosis in triptolide/lipopolysaccharide-induced hepatotoxicity

Triptolide (TP) is a major active and toxic composition of the Chinese medicine Tripterygium wilfordii Hook. F. (TWHF), exhibiting various therapeutic bioactivities. Among the toxic effects, the hepatotoxicity of TP deserves serious attention. Previously, our research group proposed a new view of TP-related hepatotoxicity: hepatic hypersensitivity under lipopolysaccharide (LPS) stimulation. However, the mechanism of TP/LPS-induced hepatic hypersensitivity remains unclear. In this study, we investigated the mechanism underlying TP/LPS-induced hypersensitivity from the perspective of the inhibition of proteasome activity, activated endoplasmic reticulum stress (ERS)-related apoptosis, and the accumulation of reactive oxygen species (ROS). Our results showed that N-acetylcysteine (NAC), a common ROS inhibitor, decreased the expression of cleaved caspase-3 and cleaved PARP, which are associated with FLIP enhancement. Moreover, 4-phenylbutyric acid (4-PBA), an ERS inhibitor, was able to alleviate TP/LPS-induced hepatotoxicity by reducing ERS-related apoptosis protein expression (GRP78, p-eIF2α/eIF2α, ATF4, CHOP, cleaved caspase-3 and cleaved PARP) and ROS levels, with ATF4 being an indispensable mediator. In addition, the proteasome activity inhibitor MG-132 further aggravated ERS-related apoptosis, which indicated that the inhibition of proteasome activity also plays an important role in TP/LPS-related liver injuries. In summary, we propose that TP/LPS may upregulate the activation of ERS-associated apoptosis by inhibiting proteasome activity and enhancing ROS production through ATF4.

Triptolide decreases podocytes permeability by regulating TET2-mediated hydroxymethylation of ZO-1

Podocyte injury or dysfunction can lead to proteinuria and glomerulosclerosis. Zonula occludens 1 (ZO-1) is a tight junction protein which connects slit diaphragm (SD) proteins to the actin cytoskeleton. Previous studies have shown that the expression of ZO-1 is decreased in chronic kidney disease (CKD). Thus, elucidation of the regulation mechanism of ZO-1 has considerable clinical importance. Triptolide (TP) has been reported to exert a strong antiproteinuric effect by inhibiting podocyte epithelial mesenchymal transition (EMT) and inflammatory response. However, the underlying mechanisms are still unclear. We found that TP upregulates ZO-1 expression and increases the fluorescence intensity of ZO-1 in a puromycin aminonucleoside (PAN)-induced podocyte injury model. Permeablity assay showed TP decreases podocyte permeability in PAN-treated podocyte. TP also upregulates the DNA demethylase TET2. Our results showed that treatment with the DNA methyltransferase inhibitors 5-azacytidine (5-AzaC) and RG108 significantly increased ZO-1 expression in PAN-treated podocytes. Methylated DNA immunoprecipitation (MeDIP) and hydroxymethylated DNA immunoprecipitation (hMeDIP) results showed that TP regulates the methylation status of the ZO-1 promoter. Knockdown of TET2 decreased ZO-1 expression and increased methylation of its promoter, resulting in the increase of podocyte permeability. Altogether, these results indicate that TP upregulates the expression of ZO-1 and decreases podocyte permeability through TET2-mediated 5 mC demethylation. These findings suggest that TP may alleviate podocyte permeability through TET2-mediated hydroxymethylation of ZO-1.

The protective effect of natural medicines in rheumatoid arthritis via inhibit angiogenesis

Rheumatoid arthritis is a chronic immunological disease leading to the progressive bone and joint destruction. Angiogenesis, accompanied by synovial hyperplasia and inflammation underlies joint destruction. Delaying or even blocking synovial angiogenesis has emerged as an important target of RA treatment. Natural medicines has a long history of treating RA, and numerous reports have suggested that natural medicines have a strong inhibitory activity on synovial angiogenesis, thereby improving the progression of RA. Natural medicines could regulate the following signaling pathways: HIF/VEGF/ANG, PI3K/Akt pathway, MAPKs pathway, NF-κB pathway, PPARγ pathway, JAK2/STAT3 pathway, etc., thereby inhibiting angiogenesis. Tripterygium wilfordii Hook. f. (TwHF), sinomenine, and total glucoside of Paeonia lactiflora Pall. Are currently the most representative of all natural products worthy of development and utilization. In this paper, the main factors affecting angiogenesis were discussed and different types of natural medicines that inhibit angiogenesis were systematically summarized. Their specific anti-angiogenesis mechanisms are also reviewed which aiming to provide new perspective and options for the management of RA by targeting angiogenesis.

Antitumor mechanisms and future clinical applications of the natural product triptolide

Triptolide (TPL) is a compound sourced from Tripterygium wilfordii Hook. F., a traditional Chinese medicinal herb recognized for its impressive anti-inflammatory, anti-angiogenic, immunosuppressive, and antitumor qualities. Notwithstanding its favorable attributes, the precise mechanism through which TPL influences tumor cells remains enigmatic. Its toxicity and limited water solubility significantly impede the clinical application of TPL. We offer a comprehensive overview of recent research endeavors aimed at unraveling the antitumor mechanism of TPL in this review. Additionally, we briefly discuss current strategies to effectively manage the challenges associated with TPL in future clinical applications. By compiling this information, we aim to enhance the understanding of the underlying mechanisms involved in TPL and identify potential avenues for further advancement in antitumor therapy.

Jian Gan powder ameliorates immunological liver injury in mice by modulating the gut microbiota and metabolic profiles

BACKGROUND

Immunological liver injury (ILI) is a common liver disease associated with the microbiota-gut-liver axis. Jian Gan powder (JGP) exhibits both protective and therapeutic effects on hepatitis virus-induced ILI in the clinic. However, the underlying mechanisms remain elusive. The aim of this study is to investigate the hepatoprotective effects and associated mechanisms of JGP in the context of gut microbiota, utilizing a mouse model of ILI.

METHODS

The mouse model was established employing Bacillus Calmette-Guérin (BCG) plus lipopolysaccharide (LPS). Following treatment with JGP (7.5, 15, or 30 g/kg), serum, liver, and fresh fecal samples were analyzed. 16S rRNA gene sequencing and untargeted metabolomics profiling were performed to assess the role of JGP on the gut microbiota and its metabolites.

RESULTS

JGP treatment markedly reduced serum IFN-γ, IL-6, IL-22, and hepatic p-STAT3 (phosphorylated transducer and activator of transcription-3) expression. In contrast, JGP increased the percentage of proliferating cell nuclear antigen-positive liver cells in treated mice. Fecal 16S rRNA gene sequencing revealed that JGP treatment restored the levels of Alloprevotella, Burkholderia-Caballeronia-Paraburkholderia, Muribaculum, Streptococcus, and Stenotrophomonas. Additionally, metabolomics analysis of fecal samples showed that JGP restored the levels of allylestrenol, eplerenone, phosphatidylethanolamine (PE) (P-20:0/0:0), sphingomyelin (SM) d27:1, soyasapogenol C, chrysin, and soyasaponin I.

CONCLUSIONS

JGP intervention improves ILI by restoring gut microbiota and modifying its metabolic profiles. These results provide a novel insight into the mechanism of JGP in treating ILI and the scientific basis to support its clinical application.

The Role of NKG2D and Its Ligands in Autoimmune Diseases: New Targets for Immunotherapy

Natural killer (NK) cells and CD8+ T cells can clear infected and transformed cells and generate tolerance to themselves, which also prevents autoimmune diseases. Natural killer group 2 member D (NKG2D) is an important activating immune receptor that is expressed on NK cells, CD8+ T cells, γδ T cells, and a very small percentage of CD4+ T cells. In contrast, the NKG2D ligand (NKG2D-L) is generally not expressed on normal cells but is overexpressed under stress. Thus, the inappropriate expression of NKG2D-L leads to the activation of self-reactive effector cells, which can trigger or exacerbate autoimmunity. In this review, we discuss the role of NKG2D and NKG2D-L in systemic lupus erythematosus (SLE), rheumatoid arthritis (RA), multiple sclerosis (MS), type I diabetes (T1DM), inflammatory bowel disease (IBD), and celiac disease (CeD). The data suggest that NKG2D and NKG2D-L play a pathogenic role in some autoimmune diseases. Therefore, the development of strategies to block the interaction of NKG2D and NKG2D-L may have therapeutic effects in some autoimmune diseases.

TP induces hepatic intolerance to FasL-mediated hepatocyte apoptosis by inhibiting XIAP

Triptolide (TP) is extracted from the traditional Chinese medicine Tripterygium wilfordii Hook. F. (TWHF). Its severe toxic side effects, especially hepatotoxicity, have limited the clinical application of TP-related drugs. In this study, we investigated the mechanism of the hepatotoxic effects of TP from the perspective that TP inhibited the expression of the pro-survival protein X-linked inhibitor of apoptosis protein (XIAP) and enhanced FasL-mediated apoptosis of hepatocytes. TP and CD95/Fas antibody (Jo-2) were administered by gavage to C57BL/6 mice for 7 consecutive days. After co-administration of TP and Jo-2, mouse livers showed large areas of necrosis and apoptosis and significantly increased Caspase-3 activity. KEGG pathway enrichment analysis indicated that TP may cause the development of liver injury through the apoptotic signaling pathway. Proteinprotein interaction networks showed that XIAP played an essential role in this process. TP reduced the protein expression of XIAP after combination treatment with Jo-2/FasL in vivo/in vitro. TP and FasL co-stimulation significantly increased microRNA-137 (miR-137) levels in AML12 cells, while inhibition of miR-137 expression induced a rebound in XIAP protein expression. In conclusion, TP presensitizes hepatocytes and enhances the sensitivity of hepatocytes to the Fas/FasL pathway by inhibiting the protein expression of XIAP, leading to hepatocyte apoptosis.

Gene expression inhibitors for the treatment of liver fibrosis: drugs under preclinical and early clinical investigation

INTRODUCTION

Liver fibrosis represents an unmet medical condition with growing incidence and only limited therapeutic options. Interfering with dysregulated gene expression was considered a specific treatment approach, and we are here reviewing the current options to modulate transcription and translation with small molecule inhibitors of involved enzymes, transcription factors or by using non-coding RNA molecules (RNA interference) or DNA antisense oligonucleotides. Despite promising results in preclinical models, only limited data are available from studies in humans.

AREAS COVERED

This expert opinion provides a general overview of how to interfere with gene expression (transcription and translation) and highlighting recent achievements in liver fibrosis.

EXPERT OPINION

Many compounds that were explored to modulate gene expression in liver fibrosis (models) were developed as anti-cancer agents. Their use in humans with impaired liver function is often impaired by the lack of specificity to inhibit only fibrosis-related genes in the liver and by associated general toxicity and narrow therapeutic windows. RNAi approaches show a higher degree of specificity and potentially less systemic toxicity. Clinical development in liver fibrosis requires close interaction between pharmaceutical companies and regulatory authorities to address topics like relevant (surrogate) endpoints to achieve meaningful readouts faster.