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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., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Triptolide (TP), a principal bioactive component extracted from traditional Chinese medicine Tripterygium wilfordii Hook. F. (TWHF), has attracted wide attention of its therapeutic effects on inflammation and autoimmune diseases. However, the therapeutic application of TP is hindered by severe cardiomyocyte toxicity and narrow therapeutic window. We previously identified that the p53 was an indispensable contributor in TP-induced myocardial injury. p53 has an inhibitory effect on IKKβ-NF-κB pathway that regulates glucose transporters (GLUT) expression. Based on these evidences, we speculate that p53 mediates TP-disturbed glucose uptake by blocking IKKβ-NF-κB signaling. This study focused on the effect of TP on cardiac glucose uptake and the role of p53 in glucose metabolism in cardiomyocytes, and p53 -/- mice. TP treatment depressed glucose consumption and ATP production resulting in myocardial damage. Incubation with ATP (5 mM) remarkably decreased the cellular damage. Immunoblotting and immunofluorescence identified that TP suppressed glucose uptake by restricting IKKβ-NF-κB signaling activation, GLUT1 and GLUT4 expression. p53 inhibition alleviated the cell damage and the compromise of glucose uptake. Mechanistically, p53 antagonist PFTα abolished TP-induced the inhibition of IKKβ, IκBα phosphorylation, p65 nuclear translocation, and GLUT1, GLUT4 expression. Consistently, in acute heart injury models, p53 deficiency upregulated IKKβ-NF-κB activation and GLUT1, GLUT4 protein levels which was also indicated as amelioration of heart histological injury after 1.2 mg kg -1 TP administration. The present findings indicate that TP-induced p53 overactivation suppresses glucose uptake by inhibiting IKKβ-NF-κB pathway and downregulating NF-κB-dependent GLUT1 and GLUT4 expression., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Triptolide (TP) isolated from Tripterygium wilfordii Hook F. (TWHF) shows extensive anti-inflammation, immunosuppression and anti-tumor properties. However, its therapeutic potential is limited by its severe side effects, especially the nephrotoxicity. This study intended to explore the role of the GSK-3β/Fyn pathway in TP-induced oxidative damage and the potential mechanism of Nrf2 protein downregulation. Our data showed that TP induced oxidative stress and cell damage in the rat renal tubular epithelial cell line NRK-52E cells by activation of GSK-3β and nuclear translocation of Fyn, which resulted in decreased Nrf2 nuclear translocation. Moreover, TP significantly induced Nrf2 degradation by ubiquitination, which was blocked by the proteasome inhibitor MG132. In addition, cotreatment with a typical GSK-3β inhibitor, lithium chloride, promoted the nuclear translocation of Nrf2 and decreased the nuclear translocation of Fyn, which led to reduced cell damage, LDH leakage, glutathione depletion and cell apoptosis. Collectively, our results indicated that TP induced oxidative damage in NRK-52E cells by facilitating Nrf2 degradation by ubiquitination via the GSK-3β/Fyn pathway., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Triptolide (TP) is the main ingredient of Chinese herb Tripterygium wilfordii Hook f. (TWHF). Despite of its multifunction in pharmaceutics, accumulating evidences showed that TP caused obvious hepatotoxicity in clinic. The current study investigated the role of Notch1 signaling in TP-induced hepatotoxicity. Our data indicated that TP inhibited the protein expression of Notch1 and its active form Notch intracellular domain (NICD) leading to increased PTEN (phosphatase and tensin homolog deleted on chromosome ten) expression. Moreover, PTEN triggered Txnip (thioredoxin-interacting protein) activation by inhibiting Akt phosphorylation, which resulted in reduction of Trx (thioredoxin). In conclusion, TP caused liver injury through initiating oxidative stress in hepatocyte. This study indicated the potency of Notch1 to protect against TP-induced hepatotoxicity., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Triptolide (TP), a major active component of Tripterygium wilfordii Hook f., is widely used in the treatment of inflammation and autoimmune disorders. Its clinical application is limited by severe adverse effects, especially cardiotoxicity. Accumulative evidences indicate that TP induces DNA damage by inhibiting RNA polymerase. Considering the relationship among DNA damage, p53, and the role of p53 in mitochondria-dependent apoptosis, we speculate that TP-induced cardiotoxicity results from p53 activation. In this study, the role of p53 in TP-induced cardiotoxicity was investigated in H9c2 cells, primary cardiomyocytes, and C57BL/6 genetic background p53 -/- mice. p53 protein level was elevated by TP in vitro and in acute heart injury models. With TP administration (1.2 mg/kg), p53 deficiency prevented heart histology injury and decreased serum cardiac troponin I (cTn-I) and apoptotic proteins. Mechanistically, immunoblotting and immunofluorescence staining identified that TP-induced toxicity is dependent on p53 nuclear translocation and transactivation of Bcl2 family genes, leading to mitochondrial outer membrane permeabilization (MOMP) and mitochondria dysfunction. Consistently, p53 antagonist PFTα counteracted TP-induced p53 overexpression and regulation of Bcl2 family transcription, which improved mitochondrial membrane integrity and prevented apoptosis. Moreover, Bax antagonist Bax inhibitor peptide (BIP) V5 ameliorated TP-induced apoptosis through suppressing membrane depolarization and ROS accumulation. These results suggest that TP-induced cardiotoxicity is p53-dependent by promoting Bax-induced mitochondria-mediated apoptosis., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Triptolide is a major active ingredient of tripterygium glycosides, used for the therapy of immune and inflammatory diseases. However, its clinical applications are limited by severe male fertility toxicity associated with decreased sperm count, mobility and testicular injures. In this study, we determined that triptoide-induced mitochondrial dysfunction triggered reduction of lactate and dysregulation of fatty acid metabolism in mouse Sertoli cells. First, triptolide induced mitochondrial damage through the suppressing of proliferator-activated receptor coactivator-1 alpha (PGC-1α) activity and protein. Second, mitochondrial damage decreased lactate production and dysregulated fatty acid metabolism. Finally, mitochondrial dysfunction was initiated by the inhibition of sirtuin 1 (SIRT1) with the regulation of AMP-activated protein kinase (AMPK) in Sertoli cells after triptolide treatment. Meanwhile, triptolide induced mitochondrial fatty acid oxidation dysregulation by increasing AMPK phosphorylation. Taken together, we provide evidence that the mechanism of triptolide-induced testicular toxicity under mitochondrial injury may involve a metabolic change., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Burkitt's lymphoma (BL) is a highly aggressive B-cell non-Hodgkin lymphoma with rapid growth and dissemination propensity. Triptolide (TP), an active component extracted from Chinese herb Tripterygium wilfordii Hook f., has broad-spectrum anti-tumor activities. This study aimed to explore the in vitro and in vivo anti-cancer effects of TP on BL and the potential molecular mechanisms. In this study, the in vitro anti-tumor activity of TP was determined by CCK-8 and flow cytometry assays in Raji, NAMALWA and Daudi cells. The expression of SIRT3, phosphorylation and acetylation of glycogen synthase kinase-3β (GSK-3β) were analyzed by Western blot assay. Moreover, we examined the mitochondrial membrane potential by JC-1 method and measured apoptosis related protein using Western blot assay. BL xenograft model in NOD/SCID mice were established to evaluate the in vivo anti-cancer effect of TP. We discovered that TP inhibited BL cell growth and induced apoptosis in a dose-dependent manner. Loss of SIRT3 provides growth advances for BL cells. However, TP could up-regulate SIRT3 expression, which resulted in suppression of BL cells proliferation. GSK-3β was activated by SIRT3-mediated deacetylation, which subsequently induced mitochondrial translocation and accumulation of Bax and decrease of mitochondrial membrane potential. Anti-tumor studies in vivo showed that TP (0.36 mg/kg) inhibited the growth of BL xenografts in NOD/SCID mice with an inhibitory rate of 73.13%. Our data revealed that TP triggered mitochondrial apoptotic pathway in BL by increasing SIRT3 expression and activating SIRT3/GSK-3β/Bax pathway. This study indicated that TP is a potential anti-cancer Chinese herbal medicine against BL., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Triptolide (TP), a diterpene triepoxide, is a major active component of Tripterygium wilfordii extracts, which are prepared as tablets and has been used clinically for the treatment of inflammation and autoimmune disorders. However, TP's therapeutic potential is limited by severe adverse effects. In a previous study, we reported that TP induced mitochondria dependent apoptosis in cardiomyocytes. Glycogen synthase kinase-3β (GSK-3β) is a multifunctional serine/threonine kinase that plays important roles in the necrosis and apoptosis of cardiomyocytes. Our study aimed to investigate the role of GSK-3β in TP-induced cardiotoxicity. Inhibition of GSK-3β activity by SB 216763, a potent and selective GSK-3 inhibitor, prominently ameliorated the detrimental effects in C57BL/6J mice with TP administration, which was associated with a correction of GSK-3β overactivity. Consistently, in TP-treated H9c2 cells, SB 216763 treatment counteracted GSK-3β overactivity, improved cell viability, and prevented apoptosis by modulating the expression of Bcl-2 family proteins. Mechanistically, GSK-3β interacted with and phosphorylated cyclophilin F (Cyp-F), a key regulator of mitochondrial permeability transition pore (mPTP). GSK-3β inhibition prevented the phosphorylation and activation of Cyp-F, and desensitized mPTP. Our findings suggest that pharmacological targeting of GSK-3β could represent a promising therapeutic strategy for protecting against cardiotoxicity induced by TP., (Copyright © 2016 Elsevier Inc. All rights reserved.)

Clinical application of triptolide (TP), a main active ingredient of the traditional Chinese herb Tripterygium wilfordii Hook f. (TWHF), is limited by a series of severe toxicities, including cardiotoxicity. In previous studies, we found the activation of sirtuin 3 (SIRT3) attenuated TP-induced toxicity in cardiomyocytes. Resveratrol (RSV), a polyphenol from the skins of grapes and red wine, is an activator of SIRT3. The current study aimed to investigate the protective effect of RSV against TP-induced cardiotoxicity and the underlying mechanisms. Mice were treated with a single dose of TP (2.5 mg/kg) via the intragastric (i.g.) route. After 24 h, TP induced abnormal changes of serum biochemistry, activity decrease of antioxidant enzymes and damage of heart tissue such as myocardial fiber rupture, cell swelling and interstitial congestion. In contrast, administration with RSV (50 mg/kg i.g. 12 h before and 2 h after the administration of TP) attenuated the detrimental effects induced by TP in BALB/c mice. Moreover, the cardiomyocyte protective effects of RSV on TP-induced heart injury were associated with the activation of SIRT3 and its downstream targets. In vitro study also indicated that RSV counteracted TP-induced cardiotoxicity through SIRT3-FOXO3 signaling pathway in H9c2 cells. Collectively, these findings suggest the potential of RSV as a promising agent in protecting heart from TP-induced damage.

Triptolide (TP), an active component of the traditional Chinese herb Tripterygium wilfordii Hook f. (TWHF), has multiple pharmacological effects. However, the severe toxicity of TP greatly restricts its clinical applications. Although TP exposure causes serious heart injury, the mechanism underlying TP-induced cardiotoxicity has rarely been investigated. In previous studies, we found that TP-induced oxidative stress was involved in the mitochondria-dependent apoptosis of cardiomyocytes. Opening of the mitochondrial permeability transition pore (mPTP) is the key to the mitochondrial dysfunction in cardiac toxicity. The aim of this study was to investigate the potential cardioprotective effects of sirtuin 3 (SIRT3) on the mPTP. In the present study, the cytotoxicity of TP was accompanied by the up-regulation of the SIRT3 protein level and its rapid aggregation in nuclei and mitochondria. The SIRT3-FOXO3 signaling pathway was activated simultaneously, resulting in increased transcription of manganese superoxide dismutase (MnSOD) and catalase (CAT) for the elimination of reactive oxygen species (ROS). In addition, augmentation of the SIRT3 level via the overexpression plasmid SIRT3-Flag provided resistance to TP-induced cellular damage, whereas knocking down the SIRT3 level via siRNA accelerated the damage. Because it is an activator of SIRT3, the protective effect of resveratrol was also evaluated in H9c2 cells. In conclusion, the current results suggest that activation of SIRT3 substantially ameliorates the detrimental effects of TP by closing the mPTP., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

Background: Triptolide, an active ingredient extracted from the Chinese herb Tripterygium wilfordii Hook f., has multiple pharmacological properties, including anti-inflammatory, immune-modulatory, and anti-proliferative activities. However, the hepatotoxicity of triptolide always limits its clinical applications., Hypothesis/purpose: Farnesoid X receptor (FXR) is a ligand-activated transcription factor that plays a key role in hepatoprotection through the maintenance of liver metabolism homeostasis. This study explored the role of FXR in triptolide-induced cytotoxicity and investigated whether activation of FXR can protect against triptolide-induced liver injury., Study Design: The role of FXR in triptolide-induced cytotoxicity was investigated in HepG2 cells. In addition, the protective effect of the selective FXR agonist GW4064 on triptolide-induced hepatotoxicity was explored in BALB/c mice., Methods: HepG2 cells were transient transfected with FXR expression plasmid or FXR-siRNA. The cytotoxicity was compared using the MTT assay. The extent of liver injury was assessed by histopathology and serum aminotransferases. The expression of FXR and its target genes were detected by Western blot and qRT-PCR., Results: The transient overexpression of FXR protected against triptolide-induced cell death, whereas FXR knockdown with a specific small interfering RNA resulted in increased cytotoxicity. In BALB/c mice, treatment with the FXR agonist GW4064 attenuated triptolide-induced liver dysfunction, structural damage, glutathione depletion and lipid peroxidation. Moreover, the livers of GW4064-treated mice showed increased expression of FXR and several related target genes involved in phase II and phase III xenobiotic metabolism., Conclusion: Taken together, these results indicate that activation of FXR attenuates triptolide-induced hepatotoxicity and provide direct implications for the development of novel therapeutic strategies against triptolide-induced hepatotoxicity., (Copyright © 2015 Elsevier GmbH. All rights reserved.)

Triptolide (TP), a major bioactive component isolated from the traditional Chinese herb Tripterygium wilfordii Hook f. (TWHF), has been shown to exert various pharmacological effects. However, the severe toxicity of TP prevents wide clinical use. In a previous study, we reported that TP-induced mitochondria-dependent apoptosis in cardiomyocytes is mediated by reactive oxygen species (ROS). Autophagy is a cellular self-digestion process and is one of the first lines of defense against oxidative stress. Additionally, recent evidence suggests that autophagy can selectively eliminate damaged mitochondria. This study investigated the role of autophagy in TP-induced cardiotoxicity. We investigated the effects of autophagy in combination with TP on apoptosis, ROS and mitochondrial function. Rat cardiomyocytes were pre-treated with chloroquine or rapamycin followed by TP. The augmentation of autophagy with rapamycin in the presence of TP substantially ameliorated the detrimental effects induced by TP, while suppression of autophagy by chloroquine accelerates TP-induced cellular damage. In addition, pre-treated with rapamycin before TP administration also attenuated TP-induced damage in Balb/c mice heart tissues. Taken together, these results suggest that TP-induced cell death can be modified by autophagy. Furthermore, induction of autophagy by rapamycin may be a potential cardioprotective role against TP-induced cardiotoxicity by facilitating removal of dysfunctional mitochondria., (Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.)

Triptolide (TP), a major active ingredient extracted from the widely used Chinese herb Tripterygium wilfordii Hook f. (TWHF), has been demonstrated to possess various biological activities. However, the clinical applications of TP are limited by its narrow therapeutic window and severe toxicity. The current study aimed to investigate the roles of reactive oxygen species (ROS) and mitochondria in TP-induced cardiac injury. Male BALB/C mice were intravenously (i.v.) treated with a single dose of TP (1.2 mg/kg). After 24h, TP induced the oxidative stress, mitochondrial dysfunction, apoptotic damage, and pathological changes of heart tissue. In vitro studies also indicated that the cytotoxic effects of TP involved the ROS-mediated mitochondria-dependent pathway in H9c2 cells. TP treatment increased the accumulation of ROS and subsequently triggered cell apoptosis by depolarizing the mitochondrial membrane potential (ΔΨm), reduced the ratio of Bax/Bcl-2, released cytochrome c and, ultimately, activated caspase-3. Nrf2, as well as its downstream antioxidants, were also suppressed by TP. Taken together, these results suggest that TP induces cardiotoxicity in vivo and in vitro via oxidative stress, which was associated with down regulated Nrf2 activation, and the mitochondria-mediated apoptotic signaling pathway., (Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.)

Triptolide, the major active component of Tripterygium wilfordii Hook f. (TWHF), has a wide range of pharmacological activities. However, the toxicities of triptolide, particularly the hepatotoxicity, limit its clinical application. The hepatotoxicity of triptolide has not been well characterized yet. The aim of this study was to investigate the role of NF-E2-related factor 2 (Nrf2) in triptolide-induced toxicity and whether activation of Nrf2 could protect against triptolide-induced hepatotoxicity. The results showed that triptolide caused oxidative stress and cell damage in HepG2 cells, and these toxic effects could be aggravated by Nrf2 knockdown or be counteracted by overexpression of Nrf2. Treatment with a typical Nrf2 agonist, sulforaphane (SFN), attenuated triptolide-induced liver dysfunction, structural damage, glutathione depletion and decrease in antioxidant enzymes in BALB/C mice. Moreover, the hepatoprotective effect of SFN on triptolide-induced liver injury was associated with the activation of Nrf2 and its downstream targets. Collectively, these results indicate that Nrf2 activation protects against triptolide-induced hepatotoxicity.

Triptolide is a major active ingredient of the Chinese herb Tripterygium wilfordii Hook f. (TWHF) and has been shown to possess multiple biological activities, such as anti-inflammatory, anti-fertility, anti-neoplastic and immunosuppressive activities. However, severe adverse effects, especially nephrotoxicity, limit its clinical use. Oxidative stress has been reported to be involved in triptolide-induced renal injury, but the existence of other mechanisms remains unclear. This study aimed to investigate whether NF-E2-related factor 2 (Nrf2), which is an antioxidant nuclear transcription factor, plays a protective role in defense against triptolide-induced toxicity in a normal rat kidney cell line (NRK-52E). Triptolide induced oxidative stress in NRK-52E cells by induction of reactive oxygen species (ROS) and depletion of glutathione (GSH), which resulted in a rapid increase in Nrf2 nuclear accumulation, as well as an induction of antioxidant response element (ARE)-driven genes. In addition, overexpression of Nrf2 protected against triptolide-induced cell death, whereas knockdown of Nrf2 by its specific small interfering RNA resulted in increased cytotoxicity. We also found that Nrf2 knockdown enhanced both the production of ROS and the depletion of GSH. Taken together, these results indicate that activation of Nrf2 plays a protective role against triptolide-induced cytotoxicity in NRK-52E cells through the counteraction of oxidative stress., (Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.)