Toxicity of triptolide and the molecular mechanisms involved

PGC-1α/NRF1-dependent cardiac mitochondrial biogenesis: A druggable pathway of calycosin against triptolide cardiotoxicity

Mitochondrion-related cardiotoxicity due to cardiotoxin stimuli is closely linked to abnormal activities of peroxisome proliferator-activated receptor gamma coactivator-1 alpha (PGC-1α), followed by co-inactivation of nuclear respiratory factor-1(NRF1). Pharmacological interventions targeting mitochondria may be effective for developing agents against cardiotoxicity. Herein, in triptolide-treated H9C2 cardiomyocytes, we observed defective mitochondrial biogenesis and respiration, characterized by depletion of mitochondrial mass and mitochondrial DNA copy number, downregulation of mitochondrial respiratory chain complexes subunits, and disorders of mitochondrial membrane potential and mitochondrial oxidative phosphorylation. Dysregulation of mitochondria led to cardiac pathological features, such as myocardial fiber fracture, intercellular space enlargement, and elevation of serum aspartate aminotransferase, creatine kinase isoenzyme, lactate dehydrogenase, and cardiac troponin I. However, following calycosin treatment, an active compound from Astragali Radix, the mitochondrion-related disorders at both cell and tissue levels were significantly ameliorated, which was facilitated by the activation of PGC-1α via deacetylation, followed by NRF1 co-activation. Calycosin-enhanced PGC-1α deacetylation is impelled by increasing sirtuin-1 expression and NAD⁺/NADH ratio. PGC-1α/NRF1 signaling in calycosin-mediated mitochondrial biogenesis protection was further confirmed by NRF1 knockdown and PGC-1α inhibition with SR18292. We conclude that calycosin ameliorated triptolide-induced cardiotoxicity by protecting PGC-1α/NRF1-dependent cardiac mitochondrial biogenesis and respiration, which is the druggable pathway for cardiotoxicity mitigation.

Immunosuppressive Sesquiterpene Pyridine Alkaloids from Tripterygium wilfordii Hook. f

Tripterygium wilfordii Hook. f. is a well-known traditional Chinese medicine used to treat autoimmune diseases. Sesquiterpene pyridine alkaloids (SPAs) are a major class of components found in this herb that have piqued the interest of researchers due to their complex and diverse structures as well as significant biological activities. In this study, ten new SPAs, wilfordatine A-J (1-10), were isolated from the roots of T. wilfordii, along with ten known analogues (11-20). Their structures were primarily elucidated by extensive 1D and 2D NMR spectroscopic analysis. To search for more immunosuppressive ingredients related to the clinical efficacy of T. wilfordii, the total alkaloids (TA) and compounds 4, 5, and 9-16 were tested for their inhibitory effects on nuclear factor-kappa B (NF-κB) pathway in Lipopolysaccharide (LPS) induced HEK293/NF-κB-Luc cells. Among them, TA, compounds 5, 11, and 16 showed potent immunosuppressive activity, with IC50 values of 7.25 μg/mL, 8.75 μM, 0.74 μM, and 15.66 μM, respectively, and no influence on the cell viability at a concentration of 100 μg/mL (TA) or 100 μM (5, 11, and 16). Accordingly, TA, 5, 11, and 16, especially 11, were identified as promising candidates for further investigation into their potential use as immunosuppressive agents.

Development of local injectable, bone-targeting nanocarriers of triptolide for treatment of bone-only metastasis

Triptolide (TP) is known for its diverse pharmacological activities but also its delivery and toxicity issues. This study aimed at exploiting TP's anticancer effects at lower risk of systemic toxicity by developing local-injectable "bone-targeting TP nanoparticle" (TPN) for bone-only metastasis treatment. The lipid/oil-based TPNs decorated with alendronate (ALE) achieved size of 70.4-111.2 nm with good dispersion stability. The drug encapsulation efficiency reached 97 % and drug release profiles were in biphasic, controlled manner lasting for 5 days in medium with serum proteins and calcium. TPNs were more cytotoxic than free TP against MDA-MB-231 breast cancer cells (IC50: 16.40 ± 0.80 nM vs 25.45 ± 1.83 nM, P < 0.05) but less cytotoxic against MC3T3-E1 osteoblasts (P < 0.05). When combined with paclitaxel or docetaxel, low dose TPN (containing 10 nM) significantly increased the effectiveness of the two chemotherapy drugs against MDA-MB-231 (IC50 values decreased from 7.3 nM to 2.5 nM for docetaxel; from 4.6 nM to 1.1 nM), indicating potent chemosensitization effects. Retardation of in vitro cancer cell migration by TPN was also observed in the standard scratch assay. ALE decoration significantly enhanced the TPN affinity for both calcium hydroxyapatite and porcine bone chip models, which led to enhancement in TP retention in the bones up to 8.1-fold versus free drug. Overall, TPN demonstrated good potential as a local-injectable, bone-targeted nanotherapy tailored for eradication of bone-only metastasis at reduced risk of systemic toxicity.

Molecular Mechanistic Pathways Targeted by Natural Compounds in the Prevention and Treatment of Diabetic Kidney Disease

Diabetic kidney disease (DKD) is one of the most common complications of diabetes, and its prevalence is still growing rapidly. However, the efficient therapies for this kidney disease are still limited. The pathogenesis of DKD involves glucotoxicity, lipotoxicity, inflammation, oxidative stress, and renal fibrosis. Glucotoxicity and lipotoxicity can cause oxidative stress, which can lead to inflammation and aggravate renal fibrosis. In this review, we have focused on in vitro and in vivo experiments to investigate the mechanistic pathways by which natural compounds exert their effects against the progression of DKD. The accumulated and collected data revealed that some natural compounds could regulate inflammation, oxidative stress, renal fibrosis, and activate autophagy, thereby protecting the kidney. The main pathways targeted by these reviewed compounds include the Nrf2 signaling pathway, NF-κB signaling pathway, TGF-β signaling pathway, NLRP3 inflammasome, autophagy, glycolipid metabolism and ER stress. This review presented an updated overview of the potential benefits of these natural compounds for the prevention and treatment of DKD progression, aimed to provide new potential therapeutic lead compounds and references for the innovative drug development and clinical treatment of DKD.

Discovery of a novel water-soluble, rapid-release triptolide prodrug with improved drug-like properties and high efficacy in human acute myeloid leukemia

In this work, a series of water-soluble triptolide prodrugs were synthesized, and their triptolide release rate, pharmacokinetic characteristics and anti-tumor effect were measured. We found that inserting glycolic acid as a linker between triptolide and the cyclic amino acid accelerated the release of triptolide from prodrugs into the plasma while preserving its safety. Among them, prodrug TP-P1 was significantly better than Minnelide (the only water-soluble triptolide prodrug in clinical trials) in terms of release rate in plasma and synthetic yield. In mouse models of human acute myeloid leukemia (AML), TP-P1 was effective in reducing xenograft tumors at dose levels as low as 25 μg/kg, and eliminating tumors at dose 100 μg/kg. Furthermore, TP-P1 could significantly enhance the efficacy of FLT3 inhibitors in the treatment of AML. These experimental results showed the potential of TP-P1 as water-soluble prodrugs of triptolide.

Metformin and histone deacetylase inhibitor based anti-inflammatory nanoplatform for epithelial-mesenchymal transition suppression and metastatic tumor treatment

Epithelial-mesenchymal transition (EMT), a differentiation process with aberrant changes of tumor cells, is identified as an initial and vital procedure for metastatic processes. Inflammation is a significant inducer of EMT and provides an indispensable target for blocking EMT, however, an anti-inflammatory therapeutic with highlighted safety and efficacy is deficient. Metformin is a promising anti-inflammatory agent with low side effects, but tumor monotherapy with an anti-inflammation drug could generate therapy resistance, cell adaptation or even promote tumor development. Combination therapies with various anti-inflammatory mechanisms can be favorable options improving therapeutic effects of metformin, here we develop a tumor targeting hybrid micelle based on metformin and a histone deacetylase inhibitor propofol-docosahexaenoic acid for efficient therapeutic efficacies of anti-inflammatory drugs. Triptolide is further encapsulated in hybrid micelles for orthotopic tumor therapies. The final multifunctional nanoplatforms (HAOPTs) with hyaluronic acid (HA) modification can target tumor efficiently, inhibit tumor cell EMT processes, repress metastasis establishment and suppress metastatic tumor development in a synergistic manner. Collectively, the results afford proof of concept that the tumor targeting anti-inflammatory nanoplatform can provide a potent, safe and clinical translational approach for EMT inhibition and metastatic tumor therapy.

Inflammation aggravated the hepatotoxicity of triptolide by oxidative stress, lipid metabolism disorder, autophagy, and apoptosis in zebrafish

Triptolide is a major compound isolated from the Tripterygium wilfordii Hook that is mainly used for the treatment of autoimmune disorders and inflammatory diseases. Though triptolide-induced hepatotoxicity has been widely reported, the hepatic effects when the patients are in an inflammatory state are not clear. In this study, we used low-dose Lipopolysaccharides (LPS) to disrupt the inflammation homeostasis in the liver of zebrafish and explored the hepatotoxicity of triptolide under an inflammatory state. Compared with the Triptolide group, LPS-Triptolide cotreatment exacerbate the liver injury with a remarkable decrease of liver size and liver-specific fluorescence intensity, accompanied by significant elevation of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) activities. Liver cell damages were further demonstrated by histological staining and scanning electron microscopy observation. Lipid metabolism was severely impaired as indicated by delayed yolk sac absorption, accumulated triglycerides in the liver, and dysregulation of the related genes, such as ppar-α, cpt-1, mgst, srebf1/2, and fasn. Oxidative stress could be involved in the molecular mechanism as the Nrf2/keap1 antioxidant pathways were down-regulated when the zebrafish in an inflammatory state. Moreover, the expression of autophagy-related genes such as beclin, atg5, map1lc3b, and atg3 was also dysregulated. Finally, apoptosis was significantly induced in responses to LPS-Triptolide co-treatment. We speculate that triptolide could exacerbate the immune response and impair lipid metabolism, resulting in enhanced sensitivity of the zebrafish liver to triptolide-induced toxic effects through disruption of the antioxidant system and induction of apoptosis.

The molecular pathogenesis of triptolide-induced hepatotoxicity

Triptolide (TP) is the major pharmacologically active ingredient and toxic component of Tripterygium wilfordii Hook. f. However, its clinical potential is limited by a narrow therapeutic window and multiple organ toxicity, especially hepatotoxicity. Furthermore, TP-induced hepatotoxicity shows significant inter-individual variability. Over the past few decades, research has been devoted to the study of TP-induced hepatotoxicity and its mechanism. In this review, we summarized the mechanism of TP-induced hepatotoxicity. Studies have demonstrated that TP-induced hepatotoxicity is associated with CYP450s, P-glycoprotein (P-gp), oxidative stress, excessive autophagy, apoptosis, metabolic disorders, immunity, and the gut microbiota. These new findings provide a comprehensive understanding of TP-induced hepatotoxicity and detoxification.

Comprehensive Evaluation of the Quality of Tripterygium Glycosides Tablets Based on Multi-Component Quantification Combined with an In Vitro Biological Assay

Tripterygium glycosides tablets (TGTs) are widely used in clinical practice to treat rheumatoid arthritis and other autoimmune diseases, with significant beneficial effects but also high toxicity, necessitating rigorous quality evaluation and control. In current study, a rapid resolution liquid chromatography tandem electrospray ionization triple quadrupole mass spectrometry (RRLC–ESI–MS/MS) method was developed and validated for the quantitative analysis of 14 components of ten batches of TGTs produced by different manufacturers, including four diterpenoids, three triterpenoids, and seven sesquiterpene alkaloids. Meanwhile, the NO inhibition effects of these TGTs were evaluated in LPS-induced RAW264.7 cells for their downstream anti-inflammatory activities, as well as their cytotoxicity. The results indicate that the TGTs from different manufacturers showed poor quality consistency, as evidenced by large variations in chemical profiles and biological effects, which may increase the risks associated with clinical use. To improve the quality status of TGTs, it is crucial to identify indicator components whose characterization can accurately reflect the efficacy and toxicity of TGTs from which they were derived. Our study reveals that triptolide, triptoquinone B, celastrol, and demethylzelaysteral considerably contributed to the anti-inflammatory activity and/or cytotoxicity of TGTs, implying that they should be further investigated as candidate indicator components for TGT quality control.

New mechanism of nephrotoxicity of triptolide: Oxidative stress promotes cGAS-STING signaling pathway

Triptolide (TPL) is a bioactive component extracted from the traditional Chinese herb Tripterygium wilfordii Hook F., and has multiple pharmacological activities, such as anti-tumor activity. However, severe adverse effects and toxicity, especially nephrotoxicity, limit its clinical application. It has been demonstrated that mitochondrial defect is a major toxic effects of TPL. In this study, we show that triptolide activated the cGAS-STING signaling pathway in kidney tubular cells in vivo and in vitro. Renal injury models were established in BALB/c mice and human tubular epithelial cells using TPL. We found that TPL enhanced the phosphorylation levels of STING, TBK1 and IRF3, and upregulated the expression of IFNβ, which is the production of cGAS-STING signaling pathway. STING inhibitor C176 had protective effects in TPL-induced nephrocyte damage. STING siRNA down regulated the expression level of IFNβ. In addition, triptolide induced an increase in protein levels of the transcription factor BACH1, while transcriptional expression of the antioxidant enzyme HMOX1 was reduced due to the increased expression of BACH1. Furthermore, oxidative stress-induced mtDNA damage and DNA leakage caused activation of the cGAS-STING signaling pathway. Altogether, cGAS-STING signaling pathway involved in TPL induced nephrotoxicity. Inhibiting cGAS-STING over-activation may be a new strategy for alleviating renal injury of triptolide.

Combined multi-omics and network pharmacology approach reveals the role of Tripterygium Wilfordii Hook F in treating HIV immunological non-responders

BACKGROUND

The HIV-1 infected immunological non-responders (INRs) are characterized by poor immune reconstitution after long-term treatment. Tripterygium Wilfordii Hook F (TwHF) pill is a traditional Chinese patent drug with extensive immunosuppressive effects and has been clinically proven efficacy in treating INRs.

PURPOSE

The therapeutic mechanism of TwHF pills in the treatment of INRs was investigated by the combined multi-omics analysis on clinical samples and network pharmacology approach.

METHODS

Clinically, the peripheral blood mononuclear cells (PBMC) samples of TwHF-treated INRs from different time points were collected to conduct the transcriptomic and proteomic profiling. Key effector pathways of TwHF were enriched and analyzed by the ingenuity pathway analysis (IPA). Computationally, the TwHF-related compounds were obtained from traditional Chinese medicine databases, and literature search and structural prediction were performed to identify TwHF-related targets. Integrated with the INR-related targets, the 'TwHF-compounds-targets-INR' network was constructed to analyze core effector targets by centrality measurement. Experimentally, the effects of TwHF compounds on the T cells activation and expression of identified targets were evaluated with in vitro cell culture.

RESULTS

33 INRs were included and treated with TwHF pills for 17 (IQR, 12-24) months. These patients experienced rapid growth in the CD4⁺ T cell counts and decreased T cell activation. The multi-omics analysis showed that the interferon (IFN)-signaling pathway was significantly inhibited after taking TwHF pills. The network pharmacology predicted the central role of the signal transducer and activator of transcription 1 (STAT1) in the 'TwHF-compounds-targets-INR' network. Further bioinformatic analysis predicted STAT1 would regulate over 58.8% of identified down-regulated genes. Cell experiments validated that triptolide (TPL) would serve as the major bioactivity compound of TwHF pills to inhibit the immune cell activation, the production of IFN-γ, the expression of downstream IFN-stimulated genes, and the phosphorylation of STAT1.

CONCLUSION

Our research is the first to systemic verify the mechanisms of TwHF in treating INRs. The IFN signaling pathway and the STAT1 would be the major effector targets of TwHF pills in treating INRs. The TPL would be the major bioactive compound to inhibit the IFN response and the phosphorylation of STAT1. Our observations suggest the basis for further application of TPL analogous in treating INRs.

SLC7A11/GPX4 Inactivation-Mediated Ferroptosis Contributes to the Pathogenesis of Triptolide-Induced Cardiotoxicity

Triptolide exhibits promising efficacy in various cancers and immune diseases while its clinical application has been strongly restricted by its severe side effects, especially cardiotoxicity. However, the underlying mechanism of triptolide-induced cardiotoxicity (TIC) remains unclear. The RNA-seq analysis of triptolide-injured AC16 human cardiomyocyte cell line hinted that ferroptosis is involved in TIC. Further experimental validations proved that triptolide triggered ferroptosis, as evidenced by significant accumulation of lipid peroxidation (4-HNE and MDA levels) and ferrous iron, as well as depletion of intracellular GSH. Furthermore, triptolide-induced iron overload involved the upregulation of TF/TRFC/DMT1 signal axis and the degradation of ferritin, which contribute to ROS generation via Fenton reaction. In addition, inhibition of the antioxidant Nrf2/HO-1 pathway was observed in TIC, which may also lead to the overproduction of lethal lipid peroxides. Mechanistically, using streptavidin-biotin affinity pull-down assay and computational molecular docking, we unveiled that triptolide directly binds to SLC7A11 to inactivate SLC7A11/GPX4 signal axis. More importantly, employment of a ferroptosis inhibitor Ferrostatin-1 alleviated TIC by partially reversing the inhibitory effects of triptolide on SLC7A11/GPX4 signal. Altogether, our study demonstrated that SLC7A11/GPX4 inactivation-mediated ferroptosis contributed to the pathogenesis of TIC. Combating ferroptosis may be a promising therapeutic avenue to prevent TIC.

Antibiotic pretreatment promotes orally-administered triptolide absorption and aggravates hepatotoxicity and intestinal injury in mice

ETHNOPHARMACOLOGICAL RELEVANCE

Triptolide (TP) exhibits extensive pharmacological activity, but its hepatotoxicity and intestinal injury are significant and limit its clinical use.

AIM OF THE STUDY

To investigate the effect of gut microbiota disturbance after antibiotic pretreatment on TP-induced hepatotoxicity, intestinal injury and their mechanism.

MATERIALS AND METHODS

We compared the characteristics of TP-induced hepatotoxicity and intestinal injury in mice with or without antibiotic pretreatment. The levels of cytokines in the serum, immunohistochemistry, and the pharmacokinetics of TP were determined.

RESULT

Antibiotic pretreatment aggravates TP-induced hepatotoxicity and ileum/colon injury. TP induces hepatotoxicity in a dose-dependent manner after antibiotic pretreatment. Serum IL-1β and IL-6 levels were increased in mice given oral TP after antibiotic pretreatment. TP can increase the expression of NLRP3 inflammasome in hepatocytes, and Oral TP after antibiotic pretreatment can significantly enhance its expression, but NLRP3 inflammasome no significant change in colon and ileum. The pharmacokinetic characteristics of TP are altered significantly by antibiotic pretreatment, as shown by a 145.87% increase in C_max, a 155.11% increase in AUC_0-t, a 155.1% increase in relative bioavailability, and a 15.44% delay in MRT. Moreover, TP causes hepatotoxicity in a time-dependent manner.

CONCLUSIONS

Antibiotic pretreatment aggravates triptolide-induced hepatotoxicity and intestinal injury through elevated inflammatory response and promoted triptolide absorption.

Triptolide Induces Liver Injury by Regulating Macrophage Recruitment and Polarization via the Nrf2 Signaling Pathway

Triptolide (TP) has limited usage in clinical practice due to its side effects and toxicity, especially liver injury. Hepatic macrophages, key player of liver innate immunity, were found to be recruited and activated by TP in our previous study. The nuclear factor-erythroid-2-related factor 2 (Nrf2) pathway exerts a protective role in TP-induced liver damage, but its effect on the functions of hepatic macrophage has not been elucidated. Here, we determined whether TP can regulate the recruitment and polarization of hepatic macrophages by inhibiting Nrf2 signaling cascade. Our results demonstrated that TP inhibited the Nrf2 signaling pathway in hepatic macrophages. The changes in hepatic macrophages were responsible for the increased susceptibility toward inflammatory stimuli, and hence, TP pretreatment could induce severe liver damage upon the stimulation of a nontoxic dose of lipopolysaccharides. In addition, the Nrf2 agonist protected macrophages from TP-induced toxicity and Nrf2 deficiency significantly aggravated liver injury by enhancing the recruitment and M1 polarization of hepatic macrophages. This study suggests that Nrf2 pathway-mediated hepatic macrophage polarization plays an essential role in TP-induced liver damage, which can serve as a potential therapeutic target for preventing hepatotoxicity induced by TP.

TP-CSO: A Triptolide Prodrug for Pancreatic Cancer Treatment

Triptolide (TP) is a potential drug candidate for the treatment of cancer, but its use was hampered by its systemic toxicity and poor water solubility. Hence, a TP-CSO prodrug was synthesized by conjugating TP to chitosan oligosaccharide (CSO), and characterized by 1H NMR, FTIR, DSC and XRD analyses. The TP-CSO containing about 4 wt% of TP exhibited excellent water solubility (15 mg/mL) compared to TP (0.017 mg/mL). Compared with TP, the pharmacokinetics of the conjugate after oral administration showed a three-fold increase in the half-life in the blood circulation and a 3.2-fold increase in AUC (0-∞). The orally administered TP-CSO could more effectively inhibit tumor progression but with much lower systemic toxicity compared with TP, indicating significant potential for further clinical trials. In conclusion, CSO-based conjugate systems may be useful as a platform for the oral delivery of other sparingly soluble drugs.

Protective Effect of XinJiaCongRongTuSiZiWan on the Reproductive Toxicity of Female Rats Induced by Triptolide

Background

Although triptolide (TP) has been widely used for the treatment of inflammatory, autoimmune diseases, and various kinds of tumors, the long experimental and clinical applications have exhibited severe reproductive system toxicity in TP-treated animals and patients. More importantly, the underlying molecular mechanism involved in TP-induced reproductive system toxicity still needs more research.

Methods

Adult female Sprague Dawley rats and human ovarian granulosa cell lines were treated with TP and then treated with XinJiaCongRongTuSiZiWan (XJCRTSZW). Histological analysis and follicle count were executed using H&E staining. Hormone (E2, AMH, FSH, LH, and INH B) concentrations, inflammation indicators (IL-1β, IL-6, and TNF-α), oxidative stress indicators (SOD, GSH-Px, and MDA), apoptosis rate, protein distribution and expression (SIRT1, AMPK, and 8-OhdG), cell viability, relative protein levels (beclin-1, LC3-II/LC3-I, p62, procaspase-3, cleaved caspase-3, p-SIRT1, SIRT1, p-AMPKα-1, AMPKα-1, Akt, and p-Akt), autophagosome were detected by ELISA, commercial biochemical detection kits, flow cytometry, immunohistochemistry, CCK-8, western blotting, and transmission electron microscope, respectively.

Results

XJCRTSZW administration notably improved the TP-treated pathological symptoms, including few mature follicles in the ovary and less granular cell layer, and disordered the arrangement of the follicle, lymphocytes and plasma cells infiltration, and necrosis, shedding, and follicular cystic dilatation of the granular layer follicle cells in the ovarian stroma. Furthermore, XJCRTSZW treatment observably enhanced the TP-induced reduction of primary follicles and secondary follicles numbers and decreased the TP-induced elevation of atretic follicle numbers and the expression of AMPK, SIRT1, and 8-OhdG in GCs in vivo. Moreover, XJCRTSZW application significantly increased the TP-induced diminishment of E2, AMH, and LNH-B concentrations, apoptosis rate, SOD and GSH-Px concentrations, and p62 protein level; however, it declined the TP-induced augmentation of MDA level, the levels of IL-1β, IL-6, and TNF-α, autophagosome, beclin-1, LC3-II/LC3-I, cleaved-caspase-3, p-AMPKα-1, and p-SIRT1 protein levels both in vivo and in vitro. Besides, XJCRTSZW treatment prominently enhanced the TP-induced decrease of cell viability in vitro.

Conclusion

XJCRTSZW can alleviate TP-induced reproductive toxicity via apoptosis, inflammation, and oxidative stress both in vivo and in vitro. Moreover, XJCRTSZW ameliorates TP-induced reproductive toxicity through AMPK/SIRT and Akt signaling axis mediated autophagy both in vivo and in vitro.

Qingluotongbi formula regulates the LXRα-ERS-SREBP-1c pathway in hepatocytes to alleviate the liver injury caused by Tripterygium wilfordii Hook. f

ETHNOPHARMACOLOGICAL RELEVANCE

Tripterygium wilfordii Hook. f. (TW) is widely used to treat autoimmune and inflammatory diseases; however, its development and application is limited by its significant association with liver injury. The compound formula Qingluotongbi (QLT) employs TW as its main component and is used to treat rheumatoid arthritis with no adverse reactions, suggesting that QLT may reduce the liver toxicity of TW.

AIM OF THE STUDY

We examined whether TW interferes with lipid metabolism to induce liver injury, and evaluated the protective effect of QLT in in vivo and in vitro experiments.

MATERIALS AND METHODS

After administration of QLT and its ingredients, HepaRG cells and SD rats were tested for biochemical indicators, hepatocytes lipid changes, and rat liver pathological changes, and then we analyzed for the gene expression of liver X receptor α (LXRα), endoplasmic reticulum stress (ERS) key proteins, sterol regulatory element binding protein-1c (SREBP-1c), and lipid-synthesizing enzymes. In HepaRG cells, the protein expression of glucose-regulated protein 78 kDa (GRP78) and LXRα was detected after addition of an LXRα inhibitor, LXRα agonist, and ERS inhibitor.

RESULTS

TW caused significant elevation of biochemical indicators and lipid droplet deposition in hepatocytes, as well as upregulated the gene expression of LXRα, ERS key proteins, SREBP-1c, and lipid-synthesizing enzymes in both in vitro and in vivo settings, and caused liver injury in rats. QLT can alleviate the lipotoxic liver injury caused by TW. LXRα agonist further activated ERS induced by TW, whereas LXRα inhibitor significantly reduced ERS and lipotoxic injury induced by TW in HepaRG cells.

CONCLUSIONS

TW upregulated LXRα to activate ERS and increased the gene expression of SREBP-1c and lipid-synthesizing enzymes, leading to increased lipid synthesis in hepatocytes to result in liver injury. QLT inhibited the LXRα-ERS-SREBP-1c pathway and reduced abnormal lipid synthesis in hepatocytes and the hepatotoxicity of TW.

Bushen Culuan Decoction Ameliorates Premature Ovarian Insufficiency by Acting on the Nrf2/ARE Signaling Pathway to Alleviate Oxidative Stress

Premature ovarian insufficiency (POI) can result in lower fertility and shorten the female reproductive span. Bushen-Culuan Decoction (BCD) is a traditional Chinese medication utilized for treating POI for many years. We previously observed that BCD protects against further deterioration of the ovarian reserve of POI patients, however, the underlying mechanism has not been well studied. Our investigation seeks to evaluate the effect of BCD on POI induced by Tripterygium wilfordii polyglycosidium (TWP) and the likely mechanistic pathways, which we hypothesize may involve the Nrf2/ARE pathway. The body weights, estrous cycle, serum hormone levels, histological follicular analysis and quantification, levels of oxidative stress biomarkers in the ovarian tissue of POI mice models were evaluated. Western blotting and RT-PCR enabled quantification of the components of the Nrf2/ARE pathway. Our results showed that BCD restored hormonal profiles and estrous cycles of POI mice similar to those observed in healthy controls. BCD reduced the numbers of atretic follicles while increasing the number of primordial follicles. BCD facilitated lower 8-OHdG and MDA levels while increasing levels of key antioxidant enzymes including GSH-Px, CAT, and SOD. Furthermore, TWP increased Bach 1, Nrf2, and Keap 1 expressions at the translational level, while decreased that of HO-1. BCD treatment also promoted nuclear translocation rates of Bach 1 and Nrf2, suppressed Keap 1 protein expression, as well as raised HO-1 protein expression. Taken together, BCD likely augments ovarian reserve by activating the Nrf2/ARE signaling pathway, which stimulated higher levels of antioxidants and suppressed oxidative stress. BCD may be an important therapeutic compound in POI.

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

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

Triptolide Shows High Sensitivity and Low Toxicity Against Acute Myeloid Leukemia Cell Lines Through Inhibiting WSTF-RNAPII Complex

Triptolide exhibits superior and broad-spectrum antitumor activity. However, the narrow safety window caused by the toxicity of triptolide limits its clinical applications. Although several characterized targets for triptolide are reported, the association between triptolide and its targets in cancer therapy is not fully understood. Here, we show that acute myeloid leukemia (AML) cell lines are sensitive to triptolide by constructing an in vitro cell and in vivo xenograft models. Meanwhile, the triptolide-induced hepatotoxicity increases with increasing dosages within the xenograft models. Additionally, the expression levels of WSTF-RPB1 are strongly associated with the sensitivity to triptolide in hematological cancer cells and can be downregulated in a dose and time-dependent manner. Finally, we show that optimizing dosing regimens can achieve the same pharmaceutical effect and reduce toxicity. In summary, this study aims to search for triptolide-sensitive cell lines as well as the underlying molecular mechanisms in order to broaden the safety window of triptolide; thus, increasing its clinical utility.

Detoxification strategies of triptolide based on drug combinations and targeted delivery methods

Tripterygium wilfordii Hook f. has a long history of use in Chinese medicine. Triptolide (TP), as its main pharmacological component, has been widely explored in various diseases, including systemic lupus erythematosus, rheumatoid arthritis and cancer. However, due to its poor water solubility, limited therapeutic range and multi-organ toxicity, TP's clinical application has been greatly hampered. To improve its clinical potential, many attenuated drug combinations have been developed based on its toxicity mechanism and targeted delivery systems aimed at its water-solubility and structure. This review, conducted a systematic review of TP detoxification strategies including drug combination detoxification strategies from metabolic and toxic mechanisms, as well as drug delivery detoxification strategies from the prodrug strategy and nanotechnology. Many detoxification strategies have demonstrated promising potential in vitro and in vivo due to previous extensive studies on TP. Therefore, summarizing and discussing TP detoxification strategies for clinical problems can serve as a reference for developing novel TP detoxification strategies, and provide opportunities for future clinical applications.

The long winding road to the safer glucocorticoid receptor (GR) targeting therapies

Glucocorticoids (Gcs) are widely used to treat inflammatory diseases and hematological malignancies, and despite the introduction of novel anti-inflammatory and anti-cancer biologics, the use of inexpensive and effective Gcs is expected to grow. Unfortunately, chronic treatment with Gcs results in multiple atrophic and metabolic side effects. Thus, the search for safer glucocorticoid receptor (GR)-targeted therapies that preserve therapeutic potential of Gcs but result in fewer adverse effects remains highly relevant. Development of selective GR agonists/modulators (SEGRAM) with reduced side effects, based on the concept of dissociation of GR transactivation and transrepression functions, resulted in limited success, and currently focus has shifted towards partial GR agonists. Additional approach is the identification and inhibition of genes associated with Gcs specific side effects. Others and we recently identified GR target genes REDD1 and FKBP51 as key mediators of Gcs-induced atrophy, and selected and validated candidate molecules for REDD1 blockage including PI3K/Akt/mTOR inhibitors. In this review, we summarized classic and contemporary approaches to safer GR-mediated therapies including unique concept of Gcs combination with REDD1 inhibitors. We discussed protective effects of REDD1 inhibitors against Gcs–induced atrophy in skin and bone and underlined the translational potential of this combination for further development of safer and effective Gcs-based therapies.

Natural plant toxins in honey: An ignored threat to human health

Consumers often believe that "natural food" is harmless, however naturally occurring toxins in food represent a health risk to humans. Honey as a natural, nutritious sweetener, is one of the most commonly consumed foods throughout the world. However, food safety concerns for honey arise when honeybees collect nectar from poisonous plants such as Rhododendron sp., Coriaria arborea, and Tripterygium wilfordii Hook F. Such honey contains natural plant toxins. Humans may develop intoxication symptoms after consuming toxic honey; in some cases, it can be fatal. As a result, toxic honey poses an often-ignored threat to public health. Typical plant toxins such as grayanotoxins, triptolides, tutin and pyrrolizidine alkaloids, have been identified in toxic honey. Although different toxic honeys elicit similar symptoms, such as vomiting, nausea, and dizziness, the mechanism of toxicity may be different. Thus, it is necessary to determine the exact toxicity mechanism of different toxins to further develop effective antidotes and cures. Another important challenge is preventing toxic honey from entering the food chain. Liquid chromatography-mass spectrometry has a wide range of applications in the detection of different toxins due to its accuracy and simplicity. More methods, however, are urgently needed to detect multiple plant-derived toxins in honey and its derivatives. Developing uniform international standards for toxin detection during quarantine using advanced techniques is critical for preventing human consumption of toxic honey.

Metabolomics reveals the role of PPARα in Tripterygium Wilfordii-induced liver injury

ETHNOPHARMACOLOGICAL RELEVANCE

Tripterygium glycosides tablets (TGT) and Tripterygium wilfordii tablets (TWT) have been used to treat autoimmune diseases clinically, however, the side effects of TWT are higher than TGT, especially for hepatotoxicity.

THE AIM OF THE STUDY

This study aims to determine the mechanism of TWT-induced liver injury.

MATERIALS AND METHODS

We performed metabolomic analysis of samples from mice with liver injury induced by TGT and TWT. Ppara-null mice were used to determine the role of PPARα in TWT-induced liver injury.

RESULTS

The results indicated that TWT induced the accumulation of medium- and long-chain carnitines metabolism, which was associated with the disruption of PPARα-IL6-STAT3 axis. PPARα agonists fenofibrate could reverse the liver injury from TWT and TP/Cel, and its protective role could be attenuated in Ppara-null mice. The toxicity difference of TWT and TGT was due to the different ratio of triptolide (TP) and celastrol (Cel) in the tablet in which TP/Cel was lower in TWT than TGT. The hepatotoxicity induced by TP and Cel also inhibited PPARα and upregulated IL6-STAT3 axis, which could be alleviated following by PPARα activation.

CONCLUSIONS

These results indicated that PPARα plays an important role in the hepatotoxicity of Tripterygium wilfordii, and PPARα activation may offer a promising approach to prevent hepatotoxicity induced by the preparations of Tripterygium wilfordii.

Targets preliminary screening for the fresh natural drug molecule based on Cosine-correlation and similarity-comparison of local network

Background

Chinese herbal medicine is made up of hundreds of natural drug molecules and has played a major role in traditional Chinese medicine (TCM) for several thousand years. Therefore, it is of great significance to study the target of natural drug molecules for exploring the mechanism of treating diseases with TCM. However, it is very difficult to determine the targets of a fresh natural drug molecule due to the complexity of the interaction between drug molecules and targets. Compared with traditional biological experiments, the computational method has the advantages of less time and low cost for targets screening, but it remains many great challenges, especially for the molecules without social ties.

Methods

This study proposed a novel method based on the Cosine-correlation and Similarity-comparison of Local Network (CSLN) to perform the preliminary screening of targets for the fresh natural drug molecules and assign weights to them through a trained parameter.

Results

The performance of CSLN is superior to the popular drug-target-interaction (DTI) prediction model GRGMF on the gold standard data in the condition that is drug molecules are the objects for training and testing. Moreover, CSLN showed excellent ability in checking the targets screening performance for a fresh-natural-drug-molecule (scenario simulation) on the TCMSP (13 positive samples in top20), meanwhile, Western-Blot also further verified the accuracy of CSLN.

Conclusions

In summary, the results suggest that CSLN can be used as an alternative strategy for screening targets of fresh natural drug molecules.

Dissecting the Crosstalk Between Nrf2 and NF-κB Response Pathways in Drug-Induced Toxicity

Nrf2 and NF-κB are important regulators of the response to oxidative stress and inflammation in the body. Previous pharmacological and genetic studies have confirmed crosstalk between the two. The deficiency of Nrf2 elevates the expression of NF-κB, leading to increased production of inflammatory factors, while NF-κB can affect the expression of downstream target genes by regulating the transcription and activity of Nrf2. At the same time, many therapeutic drug-induced organ toxicities, including hepatotoxicity, nephrotoxicity, cardiotoxicity, pulmonary toxicity, dermal toxicity, and neurotoxicity, have received increasing attention from researchers in clinical practice. Drug-induced organ injury can destroy body function, reduce the patients’ quality of life, and even threaten the lives of patients. Therefore, it is urgent to find protective drugs to ameliorate drug-induced injury. There is substantial evidence that protective medications can alleviate drug-induced organ toxicity by modulating both Nrf2 and NF-κB signaling pathways. Thus, it has become increasingly important to explore the crosstalk mechanism between Nrf2 and NF-κB in drug-induced toxicity. In this review, we summarize the potential molecular mechanisms of Nrf2 and NF-κB pathways and the important effects on adverse effects including toxic reactions and look forward to finding protective drugs that can target the crosstalk between the two.

Scalable Total Synthesis of (-)-Triptonide: Serendipitous Discovery of a Visible-Light-Promoted Olefin Coupling Initiated by Metal-Catalyzed Hydrogen Atom Transfer (MHAT)

An efficient and scalable total synthesis of (-)-triptonide is accomplished based on a metal-catalyzed hydrogen atom transfer (MHAT)-initiated radical cyclization. During the optimization of the key step, we discovered that blue LEDs significantly promoted the efficiency of reaction initiated by Co(TPP)-catalyzed MHAT. Further exploration and optimization of this catalytic system led to development of a dehydrogenative MHAT-initiated Giese reaction.

Exosome-liposome hybrid nanoparticle codelivery of TP and miR497 conspicuously overcomes chemoresistant ovarian cancer

Background

Although cisplatin-based chemotherapy has been used as the first-line treatment for ovarian cancer (OC), tumor cells develop resistance to cisplatin during treatment, causing poor prognosis in OC patients. Studies have demonstrated that overactivation of the phosphatidylinositol 3-kinase/protein kinase B/mammalian target of rapamycin (PI3K/AKT/mTOR) pathway is involved in tumor chemoresistance and that overexpression of microRNA-497 (miR497) may overcome OC chemotherapy resistance by inhibiting the mTOR pathway. However, the low transcriptional efficiency and unstable chemical properties of miR497 limit its clinical application. Additionally, triptolide (TP) was confirmed to possess a superior killing effect on cisplatin-resistant cell lines, partially through inhibiting the mTOR pathway. Even so, the clinical applications of TP are restricted by serious systemic toxicity and weak water solubility.

Results

Herein, whether the combined application of miR497 and TP could further overcome OC chemoresistance by synergically suppressing the mTOR signaling pathway was investigated. Bioinspired hybrid nanoparticles formed by the fusion of CD47-expressing tumor exosomes and cRGD-modified liposomes (miR497/TP-HENPs) were prepared to codeliver miR497 and TP. In vitro results indicated that the nanoparticles were efficiently taken up by tumor cells, thus significantly enhancing tumor cell apoptosis. Similarly, the hybrid nanoparticles were effectively enriched in the tumor areas and exerted significant anticancer activity without any negative effects in vivo. Mechanistically, they promoted dephosphorylation of the overactivated PI3K/AKT/mTOR signaling pathway, boosted reactive oxygen species (ROS) generation and upregulated the polarization of macrophages from M2 to M1 macrophages.

Conclusion

Overall, our findings may provide a translational strategy to overcome cisplatin-resistant OC and offer a potential solution for the treatment of other cisplatin-resistant tumors.

Graphical Abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s12951-022-01264-5.

Triptolide protects against white matter injury induced by chronic cerebral hypoperfusion in mice

White matter injury is the major pathological alteration of subcortical ischemic vascular dementia (SIVD) caused by chronic cerebral hypoperfusion. It is characterized by progressive demyelination, apoptosis of oligodendrocytes and microglial activation, which leads to impairment of cognitive function. Triptolide exhibits a variety of pharmacological activities including anti-inflammation, immunosuppression and antitumor, etc. In this study, we investigated the effects of triptolide on white matter injury and cognitive impairments in mice with chronic cerebral hypoperfusion induced by the right unilateral common carotid artery occlusion (rUCCAO). We showed that triptolide administration alleviated the demyelination, axonal injury, and oligodendrocyte loss in the mice. Triptolide also improved cognitive function in novel object recognition test and Morris water maze test. In primary oligodendrocytes following oxygen-glucose deprivation (OGD), application of triptolide (0.001-0.1 nM) exerted concentration-dependent protection. We revealed that the protective effect of triptolide resulted from its inhibition of oligodendrocyte apoptosis via increasing the phosphorylation of the Src/Akt/GSK3β pathway. Moreover, triptolide suppressed microglial activation and proinflammatory cytokines expression after chronic cerebral hypoperfusion in mice and in BV2 microglial cells following OGD, which also contributing to its alleviation of white matter injury. Importantly, mice received triptolide at the dose of 20 μg·kg^-1·d^-1 did not show hepatotoxicity and nephrotoxicity even after chronic treatment. Thus, our results highlight that triptolide alleviates whiter matter injury induced by chronic cerebral hypoperfusion through direct protection against oligodendrocyte apoptosis and indirect protection by inhibition of microglial inflammation. Triptolide may have novel indication in clinic such as the treatment of chronic cerebral hypoperfusion-induced SIVD.

Folate-modified triptolide liposomes target activated macrophages for safe rheumatoid arthritis therapy

Rheumatoid arthritis (RA) is an autoimmune disease characterized by synovial joint hyperplasia, joint inflammation, cartilage erosion and bone destruction. Macrophages play an essential role in the pathogenesis of RA, and folate receptor β (FR-β) is highly expressed on the surface of activated synovial macrophages in RA patients. Triptolide (TP) has anti-inflammatory properties, and it can protect the cartilage matrix, but its clinical application has been limited due to poor solubility, low bioavailability and systemic toxicity. Therefore, we constructed folate-modified triptolide liposomes (FA-TP-Lips) to target macrophages, thereby treating RA in a safe and effective way. The experiments indicated that FA-TP-Lips had properties of small particle size, uniform particle size distribution, high drug encapsulation and long circulation. Furthermore, FA-TP-Lips showed reduced cytotoxicity, increased cellular uptake and significant anti-inflammatory effects in vitro. It also inhibited osteoclastogenesis. In vivo experiments revealed that liposomes could prolong the circulation of TP in the body, as well as exhibit significant cartilage-protective and anti-inflammatory effects with lower toxicity compared with the free TP group, thereby providing a promising new approach for the treatment of RA.

Role of MicroRNA-155 in Triptolide-induced hepatotoxicity via the Nrf2-Dependent pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Triptolide (TP), the main bioactive and toxic ingredient of Tripterygium wilfordii Hook F, causes severe toxicity, particularly for hepatotoxicity. However, the underlying mechanisms for its hepatotoxicity are not entirely clear.

AIM OF THE STUDY

The purpose of the study was to explore the role of miR-155, a microRNA closely related to various liver injuries and a regulator of the nuclear factor erythroid 2-related factor 2 (Nrf2) antioxidant pathway, in TP-induced liver injury in vitro and in vivo.

MATERIALS AND METHODS

First, in vitro L02 cells were treated with different concentrations of TP. The protein levels of Nrf2 and its downstream genes Heme oxygenase1 (HO-1) were determined by Western blot. The mRNA expression of miR-155, Nrf2, NAD(P)H: quinone oxidoreductase 1 (NQO1) and HO-1 were measured using qRT-PCR. And we transfected miR-155 inhibitor and miminc before TP treatment to determine the mRNA and/or protein levels of miR-155, Nrf2 and HO-1. Then, we further confirmed the interaction between miR-155 and Nrf2 pathway in TP-induced hepatic injury in BALB/C mice. The degree of liver injury was determined by HE staining and serum biochemical. The mRNA expression of miR-155 was examined with qRT-PCR and Nrf2 and HO-1 gene expression in liver were evaluated by immunohistochemistry and/or Western blot.

RESULTS

The results showed that TP significantly induced the expression of miR-155 both in L02 cells and in rodents liver tissue, and the inhibition of miR-155 could mitigate the hepatic damages caused by TP. Further experiments demonstrated that the inhibition of miR-155 reversed the down-regulation of Nrf2 and HO-1 by TP, while the miR-155 mimic enhanced the effects of TP. Animal experiments also showed that the inhibition of miR-155 by miR-155 antagomir reversed the decrease of Nrf2 induced by TP administration.

CONCLUSIONS

These results indicated that miR-155 played an important role in TP-induced hepatotoxicity by regulating the Nrf2 signaling pathway.

An Activatable Probe with Aggregation-Induced Emission for Detecting and Imaging Herbal Medicine Induced Liver Injury with Optoacoustic Imaging and NIR-II Fluorescence Imaging

Whilte herbal medicines are widely used for health promotion and therapy for chronic conditions, inappropriate use of them may cause adverse effects like liver injury, and accurately evaluating their hepatotoxicity is of great significance for public health. Herein, an activatable probe QY-N for diagnosing herbal-medicine-induced liver injury by detecting hepatic NO with NIR-II fluorescence and multispectral optoacoustic tomography (MSOT) imaging is demonstrated. The probe includes a bismethoxyphenyl-amine-containing dihydroxanthene serving as electron donor, a quinolinium as electron acceptor, and a butylamine as recognition group and fluorescence quencher. The hepatic level of NO reacts with butylamine, thereby generating the activated probe QY-NO which exhibits a red-shifted absorption band (700-850 nm) for optoacoustic imaging and generates strong emission (910-1110 nm) for NIR-II fluorescence imaging. QY-NO is aggregation-induced-emission (AIE) active, which ensures strong emission in aggregated state. QY-N is utilized in the triptolide-induced liver injury mouse model, and experimental results demonstrate the QY-N can be activated by hepatic NO and thus be used in detecting herbal-medicine-induced liver injury. The temporal and spatial information provided by three-dimensional MSOT images well delineates the site and size of liver injury. Moreover, QY-N has also been employed to monitor rehabilitation of liver injury during treatment process.

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

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

Antitumor and toxicity study of mitochondria-targeted triptolide derivatives using triphenylphosphine (TPP+) as a carrier

Based on the higher mitochondrial membrane potential (Δψ_m) of tumor cells than normal cells, a mitochondria-targeting strategy using delocalized lipophilic cations as carriers is a promising way to improve the antitumor effect of small molecules and to reduce toxicity. Triptolide (TP) has a strong antitumor effect but is limited in the clinic due to high systemic toxicity. Mitochondria-targeted TP derivatives were designed and synthesized using triphenylphosphine cations as carriers. The optimal derivative not only maintained the antitumor activity of TP but also showed a tumor cell selectivity trend. Moreover, the optimal derivative increased the release of lactate dehydrogenase and the production of ROS, decreased Δψ_m, and arrested HepG2 cells in G0/G1 phase. In a zebrafish HepG2 xenograft tumor model, the inhibitory effect of the optimal derivative was comparable to that of TP, while it had no obvious toxic effect on multiple indicators in zebrafish at the test concentrations. This work provided some evidence to support the mitochondria-targeting strategy.

Targeted therapy of rheumatoid arthritis via macrophage repolarization

The polarization of macrophages plays a critical role in the physiological and pathological progression of rheumatoid arthritis (RA). Activated M1 macrophages overexpress folate receptors in arthritic joints. Hence, we developed folic acid (FA)-modified liposomes (FA-Lips) to encapsulate triptolide (TP) (FA-Lips/TP) for the targeted therapy of RA. FA-Lips exhibited significantly higher internalization efficiency in lipopolysaccharide (LPS)-stimulated RAW 264.7 cells than liposomes (Lips) in the absence of folate. Next, an adjuvant-induced arthritis (AIA) rat model was established to explore the biodistribution profiles of FA-Lips which showed markedly selective accumulation in inflammatory paws. Moreover, FA-Lips/TP exhibited greatly improved therapeutic efficacy and low toxicity in AIA rats by targeting M1 macrophages and repolarizing macrophages from M1 to M2 subtypes. Overall, a safe FA-modified liposomal delivery system encapsulating TP was shown to achieve inflammation-targeted therapy against RA via macrophage repolarization.

Polyamine metabolism links gut microbiota and testicular dysfunction

BACKGROUND

Male fertility impaired by exogenous toxins is a serious worldwide issue threatening the health of the new-born and causing infertility. However, the metabolic connection between toxic exposures and testicular dysfunction remains unclear.

RESULTS

In the present study, the metabolic disorder of testicular dysfunction was investigated using triptolide-induced testicular injury in mice. We found that triptolide induced spermine deficiency resulting from disruption of polyamine biosynthesis and uptake in testis, and perturbation of the gut microbiota. Supplementation with exogenous spermine reversed triptolide-induced testicular dysfunction through increasing the expression of genes related to early and late spermatogenic events, as well as increasing the reduced number of offspring. Loss of gut microbiota by antibiotic treatment resulted in depletion of spermine levels in the intestine and potentiation of testicular injury. Testicular dysfunction in triptolide-treated mice was reversed by gut microbial transplantation from untreated mice and supplementation with polyamine-producing Parabacteroides distasonis. The protective effect of spermine during testicular injury was largely dependent on upregulation of heat shock protein 70s (HSP70s) both in vivo and in vitro.

CONCLUSIONS

The present study linked alterations in the gut microbiota to testicular dysfunction through disruption of polyamine metabolism. The diversity and dynamics of the gut microbiota may be considered as a therapeutic option to prevent male infertility. Video Abstract.

Triptolide inhibits neutrophil extracellular trap formation

Background

Triptolide (PG490), as a triterpene dicyclic oxide has been reported to increase the generation of reactive oxygen species (ROS) and nitric oxide (NO) and induce apoptosis of RAW 264.7 cells in a dose-dependent manner. The activity of death NETs plays an important role in anti-bacterial processes in the human body. This study aimed to investigate the effect of triptolide (PG490) on neutrophil extracellular traps (NETs) formation.

Methods

After isolating peripheral blood neutrophils from healthy volunteers, cells were incubated with PG490 to observe and detect the level of NETs and detect the level of reactive oxygen species (ROS). The cells were cultured, stained and analyzed by fluorescence microscopy.

Results

Compared with the 12-myristate-13-acetate (PMA) group, the average fluorescence intensity of SYTOX Green in the PG490 + PMA group, as detected by a multifunctional microplate reader, was significantly decreased. Intracellular ROS were labeled by fluorescence, with fluorescence intensity then measured by multifunctional microplate reader and flow cytometry. The results showed that compared with the control group, the fluorescence intensity of the PMA group was significantly increased, while there was no significant difference between PMA group and PG490 + PMA group.

Conclusions

The production of NETs is inhibited by PG490 in vitro, which is not associated with the level of cellular ROS. This suggests that PG490in Tripterygium wilfordii Hook F can suppress related diseases.

Triptolide improves myocardial fibrosis in rats through inhibition of nuclear factor kappa B and NLR family pyrin domain containing 3 inflammasome pathway

Myocardial fibrosis (MF) is the result of persistent and repeated aggravation of myocardial ischemia and hypoxia, leading to the gradual development of heart failure of chronic ischemic heart disease. Triptolide (TPL) is identified to be involved in the treatment for MF. This study aims to explore the mechanism of TPL in the treatment of MF. The MF rat model was established, subcutaneously injected with isoproterenol and treated by subcutaneous injection of TPL. The cardiac function of each group was evaluated, including LVEF, LVFS, LVES, and LVED. The expressions of ANP, BNP, inflammatory related factors (IL-1β, IL-18, TNF-α, MCP-1, VCAM-1), NLRP3 inflammasome factors (NLRP3, ASC) and fibrosis related factors (TGF-β1, COL1, and COL3) in rats were dete cted. H&E staining and Masson staining were used to observe myocardial cell inflammation and fibrosis of rats. Western blot was used to detect the p-P65 and t-P65 levels in nucleoprotein of rat myocardial tissues. LVED and LVES of MF group were significantly upregulated, LVEF and LVFS were significantly downregulated, while TPL treatment reversed these trends; TPL treatment downregulated the tissue injury and improved the pathological damage of MF rats. TPL treatment downregulated the levels of inflammatory factors and fibrosis factors, and inhibited the activation of NLRP3 inflammasome. Activation of NLRP3 inflammasome or NF-κB pathway reversed the effect of TPL on MF. Collectively, TPL inhibited the activation of NLRP3 inflammasome by inhibiting NF-κB pathway, and improved MF in MF rats.

Hyperin Alleviates Triptolide-Induced Ovarian Granulosa Cell Injury by Regulating AKT/TSC1/mTORC1 Signaling

Premature ovarian insufficiency (POI) is characterized by the loss of ovarian function before 40 years of age and affects approximately 1% of women worldwide. Caragana sinica is a traditional Miao (a Chinese ethnic minority) medicine that improves ovarian function and follicular development. In the present study, we aimed to investigate the effect of active ingredients of C. sinica on POI and determine underlying mechanisms. Herein, the chemical composition of the C. sinica compound was analyzed using ultra-high-performance liquid chromatography, which identified hyperin (HR) as one of the main ingredients in C. sinica. Then, interaction targets of HR and POI were predicted and analyzed using network pharmacology and bioinformatics. The effect of HR on triptolide (TP)-induced granulosa cell injury was evaluated, and the underlying mechanism was explored based on bioinformatic results. A total of 100 interaction targets for POI and HR were obtained. The protein-protein interaction network of identified interaction targets emphasized the topological importance of AKT1. Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis revealed that HR might regulate POI by modulating the mechanistic target of rapamycin (mTOR) signaling pathway. In addition, the KEGG graph of the mTOR signaling pathway revealed that AKT phosphorylation inhibits the TSC1/2, while TSC1/2 activation inhibits the expression of mTORC1. The fundamental experiment revealed that HR increased proliferation, progesterone receptor levels, and estradiol levels decreased by TP in KGN cells. Additionally, HR alleviated TP-induced apoptosis and G1/G1 phase arrest in KGN cells. Western blotting demonstrated that HR increased the phosphorylation of AKT and mTORC1 and decreased TSC1 expression in TP-induced KGN cells. Collectively, our findings revealed that HR alleviates TP-induced granulosa cell injury by regulating AKT/TSC1/mTORC1 signaling, providing insight into the treatment of POI.

The Efficacy of Triptolide in Preventing Diabetic Kidney Diseases: A Systematic Review and Meta-Analysis

Ethnopharmacological Relevance: Triptolide (TP), the primary biologically active ingredient of Tripterygium wilfordii Hook F (TWHF), possesses the potential to solve the shortcomings of TWHF in treating diabetic kidney disease (DKD) in the clinic. Aim of the Study: We conducted a meta-analysis to evaluate the efficacy of TP in treating DKD and offer solid evidence for further clinical applications of TP. Materials and Methods: Eight databases (CNKI, VIP, CBM, WanFang, PubMed, Web of Science, EMBASE, and Cochrane library) were electronically searched for eligible studies until October 17, 2020. We selected animal experimental studies using TP versus renin-angiotensin system inhibitors or nonfunctional liquids to treat DKD by following the inclusion and exclusion criteria. Two researchers independently extracted data from the included studies and assessed the risk of bias with the Systematic Review Centre for Laboratory Animal Experimentation Risk of Bias tool. Fixed-effects meta-analyses, subgroup analyses, and meta-regression were conducted using RevMan 5.3 software. Inplasy registration number: INPLASY2020100042. Results: Twenty-six studies were included. Meta-analysis showed that TP significantly reduced albuminuria (14 studies; standardized mean difference SMD: -1.44 [-1.65, -1.23], I2 = 87%), urine albumin/urine creatinine ratio (UACR) (8 studies; SMD: -5.03 [-5.74, -4.33], I2 = 84%), total proteinuria (4 studies; SMD: -3.12 [-3.75, -2.49], I2 = 0%), serum creatinine (18 studies; SMD: -0.30 [-0.49, -0.12], I2 = 76%), and blood urea nitrogen (12 studies; SMD: -0.40 [-0.60, -0.20], I2 value = 55%) in DKD animals, compared to the vehicle control. However, on comparing TP to the renin-angiotensin system (RAS) inhibitors in DKD treatment, there was no marked difference in ameliorating albuminuria (3 studies; SMD: -0.35 [-0.72, 0.02], I2 = 41%), serum creatinine (3 studies; SMD: -0.07 [-0.62, 0.48], I2 = 10%), and blood urea nitrogen (2 studies; SMD: -0.35 [-0.97, 0.28], I2 = 0%). Of note, TP exhibited higher capacities in reducing UACR (2 studies; SMD: -0.66 [-1.31, -0.01], I2 = 0%) and total proteinuria (2 studies; SMD: -1.18 [-1.86, -2049], I2 = 0%). Meta-regression implicated that the efficacy of TP in reducing DKD albuminuria was associated with applied dosages. In addition, publication bias has not been detected on attenuating albuminuria between TP and RAS inhibitors after the diagnosis of DKD. Systematic Review Registration: https://clinicaltrials.gov/, identifier INPLASY2020100042.

Activation of AMPK by triptolide alleviates nonalcoholic fatty liver disease by improving hepatic lipid metabolism, inflammation and fibrosis

BACKGROUND

Triptolide is naturally isolated from Tripterygium wilfordii Hook F., possessing multiple biological activities. Hepatotoxicity is one of the main side effects of triptolide. However, the effect of triptolide on nonalcoholic fatty liver disease remains unknown (NAFLD).

PURPOSE

This study aimed to observe the amelioration of triptolide against NAFLD and investigate the engaged mechanism.

METHODS

Two typical animal models of NAFLD, obese db/db mice and methionine/choline-deficient (MCD) diet-fed mice, were used. Hepatic steatosis, inflammation, and fibrosis were evaluated by H&E and Masson staining. Oil red O staining and lipid extraction analysis were used to detect fat content in mice livers. Expression of lipid metabolism, inflammatory and fibrogenic genes was also detected by Real-time PCR and Western blotting, respectively. Phosphoproteomics, molecular docking, and TR-FRET assay were performed to provide further insight into how triptolide improved NAFLD.

RESULTS

Intraperitoneal injection of triptolide at a daily dose of 50 μg/kg significantly alleviated MCD diet-induced nonalcoholic steatohepatitis (NASH), but 100 μg/kg triptolide caused severe hepatotoxicity. Pathological staining confirmed low-dose triptolide treatment reducing hepatic lipid deposition, inflammation, and fibrosis in NASH. Serum biochemical analysis revealed a reduction in the level of liver enzymes and bilirubin. MCD also induced rising expression of typical genes and proteins related to fibrosis (fibronectin, α-SMA, collagens, TGF-β) and inflammation (ILs, TNF-α, MCP-1), which was suppressed by low-dose triptolide. Data from the proteomics/phosphoproteomics and TR-FRET assay indicated triptolide was a potential allosteric AMPK agonist to increase the phosphorylation on Thr172 residue, with the EC₅₀ of 277.78 μM and 231.02 μM for AMPKα1 and AMPKα2, respectively. Moreover, triptolide exhibited an ability to activate AMPK and further led to increasing ACC1 phosphorylation in the liver. The positive results that triptolide ameliorated hepatic lipogenesis, fatty acid oxidation, and fibrosis of NAFLD via activating AMPK were further confirmed in db/db mice with 10-week intervention (50 μg/kg, i.v., twice a week).

CONCLUSION

This study demonstrates that dose-related triptolide as an allosteric AMPK agonist has the potential to alleviate NAFLD without hepatotoxicity.

Palliative effects of metformin on testicular damage induced by triptolide in male rats

As a widely existing traditional Chinese medicine component, TP (triptolide) has serious reproductive toxicity which causes severe damage to the reproductive system and limits its application prospect. TP and MET (metformin) have shown great potential in combined with each other in anticancer and anti-inflammatory. Whether metformin can resist the reproductive toxicity caused by triptolide, the effects of MET on TP-induced reproductive capacity has not been reported. In this study, metformin was used to investigate the therapeutic effect on reproductive toxicity induced by TP in rat. The results showed that metformin had significant therapeutic effects on oxidative stress damage, destruction of the blood-testosterone barrier and apoptosis. And it proved that its therapeutic effect is mainly to restore the structural and functional stability of testis through antioxidant stress. It will provide guidance for the treatment of reproductive toxicity caused by TP and the adjuvant detoxification of TP application.

Triptolide decreases rheumatoid arthritis fibroblast-like synoviocyte proliferation, invasion, inflammation and presents a therapeutic effect in collagen-induced arthritis rats via inactivating lncRNA RP11-83J16.1 mediated URI1 and β-catenin signaling

OBJECTIVE

Our previous study observed that long non-coding RNA (lncRNA) RP11-83J16.1 promoted rheumatoid arthritis (RA)-fibroblast-like synoviocyte (RA-FLS) proliferation, invasion and inflammation, which was downregulated by triptolide treatment. Therefore, the present study aimed to further investigate the mechanism and interaction between triptolide and lncRNA RP11-83J16.1 in RA treatment in vitro and in vivo.

METHODS

RA-FLS was isolated and treated by different concentration of triptolide and lncRNA RP11-83J16.1 overexpression plasmid. Furthermore, collagen-induced arthritis (CIA) rat model was constructed followed by triptolide and lncRNA RP11-83J16.1 overexpression plasmid treatment.

RESULTS

Triptolide inhibited RA-FLS viability and lncRNA RP11-83J16.1 expression in a dose-dependent manner. Afterward, triptolide treatment inhibited RA-FLS proliferation, invasion, levels of inflammatory markers (TNF-α, IL-1β, IL-6, MMP-3, and MMP-9), inactivated lncRNA RP11-83J16.1, URI1 and β-catenin signaling, but promoted apoptosis. However, lncRNA RP11-83J16.1 overexpression weakened the effects of triptolide on regulating RA-FLS cell behaviors, URI1 signaling and β-catenin signaling. In CIA model, triptolide decreased arthritis score, hyperproliferation of synovial cells, inflammation infiltration of synovial tissue, inflammatory markers (TNF-α, IL-1β, IL-6, MMP-3, and MMP-9), inactivated lncRNA RP11-83J16.1, URI1 and β-catenin signaling, but increased cell apoptosis rate of synovial tissue. Nevertheless, lncRNA RP11-83J16.1 curtailed the treatment effect of triptolide in CIA model.

CONCLUSION

Triptolide decreases RA-FLS proliferation, invasion, inflammation and presents a therapeutic effect in CIA model via inactivating lncRNA RP11-83J16.1 mediated URI1 and β-catenin signaling.

Triptolide impairs glycolysis by suppressing GATA4/Sp1/PFKP signaling axis in mouse Sertoli cells

Triptolide (TP), a primary bioactive ingredient isolated from the traditional Chinese herbal medicine Tripterygium wilfordii Hook. F. (TWHF), has attracted great interest for its therapeutic biological activities in inflammation and autoimmune disease. However, its clinical use is limited by severe testicular toxicity, and the underlying mechanism has not been elucidated. Our preliminary evidence demonstrated that TP disrupted glucose metabolism and caused testicular toxicity. During spermatogenesis, Sertoli cells (SCs) provide lactate as an energy source to germ cells by glycolysis. The transcription factors GATA-binding protein 4 (GATA4) and specificity protein 1 (Sp1) can regulate glycolysis. Based on this evidence, we speculate that TP causes abnormal glycolysis in SCs by influencing the expression of the transcription factors GATA4 and Sp1. The mechanism of TP-induced testicular toxicity was investigated in vitro and in vivo. The data indicated that TP decreased glucose consumption, lactate production, and the mRNA levels of glycolysis-related transporters and enzymes. TP also downregulated the protein expression of the transcription factors GATA4 and Sp1, as well as the glycolytic enzyme phosphofructokinase platelet (PFKP). Phosphorylated GATA4 and nuclear GATA4 protein levels were reduced in a dose- and time-dependent manner after TP incubation. Similar effects were observed in shGata4-treated TM4 cells and BALB/c mice administered 0.4 mg/kg TP for 28 days, and glycolysis was also inhibited. Gata4 knockdown downregulated Sp1 and PFKP expression. Furthermore, the Sp1 inhibitor plicamycin inhibited PFKP protein levels in TM4 cells. In conclusion, TP inhibited GATA4-mediated glycolysis by suppressing Sp1-dependent PFKP expression in SCs and caused testicular toxicity.