Conjugating glucosamine to triptolide to enhance its protective effect against renal ischemia-reperfusion injury and reduce its toxicity

Inflammation-targeted sialic acid-dexamethasone conjugates for reducing the side effects of glucocorticoids

As a potent glucocorticoid drug (GCs), Dexamethasone (Dex) is widely used clinically for the treatment of inflammatory diseases. However, such side effects as Cushing's syndrome and osteoporosis caused severe distress to patients. Herein, a sialic acid (SA)-modified dexamethasone conjugate (Dex-SA) was synthesized successfully to reduce side effects by targeting inflammatory diseases. The solubility of Dex-SA in water reached 58 times that of Dex, which meets the need for intravenous administration. The excellent stability of Dex-SA in plasma also laid a foundation for targeting disease sites. According to cellular uptake and biodistribution experiments, Dex-SA was more readily to be taken up by inflammatory cells and accumulated in diseased kidneys compared to Dex, which is attributed to the interaction of SA with E-selectin receptors overexpressed on the surface of inflammatory vascular endothelial cells. Besides, the pharmacodynamics studies of acute kidney injury showed that Dex-SA and Dex could produce comparable therapeutic effects. More importantly, Dex-SA was found to significantly reduce Dex-related side effects, as measured by blood glucose, red blood cells and immune cells, etc. At last, molecular docking results were obtained to confirm that Dex-SA could enter the cells by binding specifically with the E-selectin receptor, for combination with glucocorticoid receptors in the cytoplasm to exert pharmacological effects. Our study is expected to contribute a new strategy to the safe and effective targeting treatment of inflammatory diseases.

Therapeutic Potential of Triptolide in Treating Bone-Related Disorders

Triptolide, a diterpene triepoxide, is a pharmacologically active compound isolated from a Chinese medicinal herb Tripterygium wilfordii Hook F (TwHF). Triptolide has attracted considerable attention in recent times due to its multiple biological and pharmaceutical activities, with an emphasis on therapeutic importance in the treatment of diverse disorders. With essential medicinal implications, TwHF's extracts have been used as anti-inflammatory, antiproliferative, antioxidative, and immunosuppressive agents for centuries, with continuous and relevant modifications to date to enhance its utility in several diseases and pathophysiology. Here, in this review, we accentuate the studies, highlighting the effects of triptolide on treating bone-related disorders, both inflammatory and cancerous, particularly osteosarcoma, and their manifestations. Based on this review, future avenues could be estimated for potential research strategies, molecular mechanisms, and outcomes that might contribute toward reinforcing new dimensions in the clinical application of triptolide in treating bone-related disorders.

Design, synthesis of novel triptolide-glucose conjugates targeting glucose Transporter-1 and their selective antitumor effect

Six positional isomers of triptolide-glucose conjugates (TG1α, TG1β, TG2, TG3, TG4 and TG6) were designed and synthesized. These conjugates exhibited better water solubility, and had selective cytotoxicity between tumor cells with high expression of glucose transport-1 (Glut-1) and non-tumor cells with low expression of Glut-1, in which TG2 formed by triptolide (TPL) and d-glucose C2-OH had the strongest cytotoxicity to tumor cells and lowest toxicity in non-tumor cells, therefore the highest relative therapeutic index, which was 5.7 times that of triptolide and consequent the most powerful selective antitumor activity in vitro. The cytotoxicity of TG2 was highly correlated with Glut-1 function. As a prodrug of triptolide, TG2 could promote RNA Pol II degradation and induce apoptosis as TPL does. TG2 had a stronger dose-dependent antitumor effect in vivo than TPL and no adverse reaction occurred when its tumor inhibition was higher than 90%, which was associated with its selective distribution in tumor tissues. TG2 could be used as a promising drug candidate for the treatment of solid tumors with high expression of Glut-1, which is worthy of further study.

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.

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.

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

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

Therapeutic and delivery strategies of phytoconstituents for renal fibrosis

Chronic kidney disease (CKD) is one of the most common diseases endangering human health and life. By 2030, 14 per 100,000 people may die from CKD. Renal fibrosis (RF) is an important intermediate link and the final pathological change during CKD progression to the terminal stage. Therefore, identifying safe and effective treatment methods for RF has become an important goal. In 2018, the World Health Organization introduced traditional Chinese medicine into its effective global medical program. Various phytoconstituents that affect the RF process have been extracted from different plants. Here, we review the potential therapeutic capabilities of active phytoconstituents in RF treatment and discuss how phytoconstituents can be structurally modified or combined with other ingredients to enhance efficiency and reduce toxicity. We also summarize phytoconstituent delivery strategies to overcome renal barriers and improve bioavailability and targeting.

Nanotechnology, Nanomedicine, and the Kidney

The kidneys are vital organs performing several essential functions. Their primary function is the filtration of blood and the removal of metabolic waste products as well as fluid homeostasis. Renal filtration is the main pathway for drug removal, highlighting the importance of this organ to the growing field of nanomedicine. The kidneys (i) have a key role in the transport and clearance of nanoparticles (NPs), (ii) are exposed to potential NPs’ toxicity, and (iii) are the targets of diseases that nanomedicine can study, detect, and treat. In this review, we aim to summarize the latest research on kidney-nanoparticle interaction. We first give a brief overview of the kidney’s anatomy and renal filtration, describe how nanoparticle characteristics influence their renal clearance, and the approaches taken to image and treat the kidney, including drug delivery and tissue engineering. Finally, we discuss the future and some of the challenges faced by nanomedicine.

Pharmacokinetics, distribution and efficacy of triptolide PLGA microspheres after intra-articular injection in a rat rheumatoid arthritis model

The UPLC-MS/MS method was established with good precision, accuracy and stability to determine the concentrations of TPL in biological samples, such as heart, liver, spleen, lung, kidney, plasma and joint.After being made into microspheres, TPL can stay in the joint tissue for a long time, further reducing the number of times joint cavity administration, and its sustained release effect was significantly improved compared with the solution dosage form.The pharmacokinetic parameters, such as AUC_(0-t), AUC_(0-∞), T_1/2, T_max, MTR_(0-t), and MTR_(0-∞) of the TPL-PLGA-MS group were significantly increased compared with those of the solution group. The microsphere preparation could significantly slow the release rate of the drug from the joint cavity.TPL-PLGA-MS can significantly reduce the expression of inflammatory factors such as IL-1, IL-6, TNF-α and hs-CRP. TPL-PLGA-MS for articular cavity injection has potential as a new preparation for the treatment of RA.

Triptolide: reflections on two decades of research and prospects for the future

Covering: 2000 to 2020 Triptolide is a bioactive diterpene triepoxide isolated from Tripterygium wilfordii Hook F, a traditional Chinese medicinal plant whose extracts have been used as anti-inflammatory and immunosuppressive remedies for centuries. Although triptolide and its analogs exhibit potent bioactivities against various cancers, and inflammatory and autoimmune diseases, none of them has been approved to be used in the clinic. This review highlights advances in material sourcing, molecular mechanisms, clinical progress and new drug design strategies for triptolide over the past two decades, along with some prospects for the future course of development of triptolide.

Molecularly Engineering Triptolide with Aptamers for High Specificity and Cytotoxicity for Triple-Negative Breast Cancer

Triple-negative breast cancer (TNBC) lacks three important receptors, ER, PR, and HER2. It is more aggressive and more likely to relapse after treatment, thus has been identified as one of the most malignant breast cancer types. The development of efficient targeted TNBC therapy is an important research topic in TNBC treatment. We report the development of a new aptamer-drug conjugate (ApDC), AS1411-triptolide conjugate (ATC), as targeted therapy for the treatment of TNBC with high efficacy. The conjugate possesses excellent specificity and high cytotoxicity against the MDA-MB-231 cell line. The advantages of our newly invented ATC are further highlighted by its excellent in vivo anti-TNBC efficacy and negligible side effects toward healthy organs.

Preclinical Pharmacokinetics of Triptolide: A Potential Antitumor Drug

Background:

Triptolide, a bioactive component in Tripterygium wilfordii extracts, possess strong antiproliferative activity on all 60-National Cancer Institute (NCI) cancer cell lines. However, the widespread use of triptolide in the clinical practice is greatly limited for its multi-organ toxicity and narrow therapeutic window. All the toxic characteristics of triptolide are associated with the pharmacokinetics especially its distribution and accumulation in the target organ.

Methods:

The literature review was done using PubMed search, SciFinder and Google Scholar databases with specific keywords such as triptolide, pharmacokinetics, drug-drug interaction, transporters, metabolism, modification to collect the related full-length articles and abstracts from 2000 to 2018.

Results:

Oral triptolide is rapidly and highly absorbed. Grapefruit juice affects oral absorption, increasing the area under the concentration-time curve (AUC) by 153 % and the maximum concentration (Cmax) by 141 %. The AUC and the Cmax are not dose proportional. Triptolide distributes into the liver, heart, spleen, lung and kidney. Biotransformation of triptolide in rats includes hydroxylation, sulfate, glucuronide, N-acetylcysteine (NAC) and Glutathione (GSH) conjugation and combinations of these pathways. Less than 4 % of triptolide was recovered from the feces, bile and urine within 24 h. After repeating dosage, triptolide was eliminated quickly without accumulation in vivo. As a substrate of P-glycoprotein (P-gp) and CYP3A4, triptolide could have clinically significant pharmacokinetic interactions with those proteins substrates/inhibitors.

Conclusion:

The findings of this review confirm the importance of pharmacokinetic character for understanding the pharmacology and toxicology of triptolide.

Kidney-targeted triptolide-encapsulated mesoscale nanoparticles for high-efficiency treatment of kidney injury

Insolubility and toxicity of TP restrict clinical applications in renal diseases. Here, TP-encapsulated mesoscale nanoparticles offer a new therapeutic strategy for renal diseases due to good biocompability, kidney targeting and slow release.

Renal-targeting triptolide-glucosamine conjugate exhibits lower toxicity and superior efficacy in attenuation of ischemia/reperfusion renal injury in rats

AIM

We previously reported a novel triptolide (TP)-glucosamine conjugate (TPG) that specifically accumulated in kidneys and protected renal function from acute ischemia/reperfusion (I/R) injury in rats. In this study we further examined the molecular mechanisms underlying the renoprotective action of TPG.

METHODS

The renal-targeting of TPG was investigated in a human proximal renal tubular epithelial cell line (HK-2) by measuring cell uptake of TP or TPG. The effects of TP or TPG on cell cycle distribution and apoptosis rate of HK-2 cells were assessed, and the activities of caspase-3 and caspase-9 were also measured. SD rats were subjected to bilateral renal ischemia by temporarily clamping both renal pedicles. The rats were administered TP (4.17 μmol·kg-1·d-1, iv) or TPG (4.17 μmol·kg-1·d-1, iv) for 3 d before the renal surgery. The kidneys were harvested after 24 h of recovery from the surgery. The levels of oxidative stress, proinflammatory cytokines, chemotactic cytokines and intracellular adhesion molecules in kidneys were examined.

RESULTS

The uptake of TPG in HK-2 cells was 2-3 times higher than that of TP at the concentrations tested. Furthermore, TPG targeting the proximal tubules was mediated through interactions with megalin receptors. TP (40-160 nmol/L) concentration-dependently increased G2/M arrest, apoptosis and caspase-3/caspase-9 activity in HK-2 cells, whereas the same concentrations of TPG did not show those features when compared with the control group. In I/R-treated rats, TPG administration caused more robust down-regulation of proinflammatory cytokines (TNF-α, IL-6, IL-1, TGF-β) and chemotactic cytokines (MCP-1) in the kidneys compared with TP administration, suggesting the inhibition of the proliferation and accumulation of lymphocytes. And TPG administration also caused more prominent inhibition on the levels of oxidative stress and intracellular adhesion molecules in the kidneys, compared with TP administration.

CONCLUSION

The renal-targeting TPG is more effective and less toxic than TP, in amelioration of I/R-induced rat renal injury, which may provide a new avenue for the treatment of acute kidney injury.