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

• Published in: Acta pharmacologica Sinica Vol. 37; no. 11; pp. 1467 - 1480
• Main Authors: Fu, Yu, Lin, Qing, Gong, Tao, Sun, Xun, Zhang, Zhi-rong
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 01.11.2016; Nature Publishing Group
• Subjects: Acute Kidney Injury - drug therapy; Acute Kidney Injury - metabolism; Acute Kidney Injury - pathology; Animals; Apoptosis; Biomedical and Life Sciences; Biomedicine; Cell Adhesion; Cell Adhesion Molecules - metabolism; Cell Line; Cell Movement; Diterpenes - therapeutic use; Diterpenes - toxicity; Glucosamine - therapeutic use; Glucosamine - toxicity; Humans; Immunology; Internal Medicine; Ischemia - drug therapy; Ischemia - metabolism; Ischemia - pathology; Kidney - blood supply; Kidney - drug effects; Kidney - metabolism; Kidney - pathology; Kidney Tubules - metabolism; Kidney Tubules - pathology; Leukocytes - physiology; Lipid Peroxidation; Male; Medical Microbiology; Molecular Targeted Therapy; Necrosis; Original; original-article; Oxidative Stress; Pharmacology/Toxicology; Rats, Sprague-Dawley; Reperfusion Injury - drug therapy; Reperfusion Injury - metabolism; Reperfusion Injury - pathology; Vaccine; ischemia/reperfusion; triptolide-glucosamine conjugate; proinflammatory cytokines; M phase arrest; G; renal targeting; triptolide; apoptosis; acute kidney injury; renoprotection; oxidative stress
• ISSN: 1671-4083; 1745-7254; 1745-7254
• DOI: 10.1038/aps.2016.44

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 GJM 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.