Dihydromyricetin attenuates cisplatin-induced acute kidney injury by reducing oxidative stress, inflammation and ferroptosis.

BACKGROUND: Cisplatin is effective against various types of cancers. However, its clinical application is limited owing to its adverse effects, especially acute kidney injury (AKI). Dihydromyricetin (DHM), a flavonoid derived from Ampelopsis grossedentata, has varied pharmacological activities. This research aimed to determine the molecular mechanism for cisplatin-induced AKI. METHODS: A murine model of cisplatin-induced AKI (22 mg/kg, I.P.) and a HK-2 cell model of cisplatin-induced damage (30 µM) were established to evaluate the protective function of DHM. Renal dysfunction markers, renal morphology and potential signaling pathways were investigated. RESULTS: DHM decreased the levels of renal function biomarkers (blood urea nitrogen and serum creatinine), mitigated renal morphological damage, and downregulated the protein levels of kidney injury molecule-1 and neutrophil gelatinase-associated lipocalin. It upregulated the expression levels of antioxidant enzymes (superoxide dismutase and catalase expression), nuclear factor-erythroid-2-related factor 2 (Nrf2) and its downstream proteins, including heme oxygenase-1 (HO-1), glutamate-cysteine ligase catalytic (GCLC) and modulatory (GCLM) subunits, thus eventually reducing cisplatin-induced reactive oxygen species (ROS) production. Moreover, DHM partially inhibited the phosphorylation of the active fragments of caspase-8 and -3 and mitogen-activated protein kinase and restored glutathione peroxidase 4 expression, which attenuated renal apoptosis and ferroptosis in cisplatin-treated animals. DHM also mitigated the activation of NLRP3 inflammasome and nuclear factor (NF)-κB, attenuating the inflammatory response. In addition, it reduced cisplatin-induced HK-2 cell apoptosis and ROS production, both of which were blocked by the Nrf2 inhibitor ML385. CONCLUSIONS: DHM suppressed cisplatin-induced oxidative stress, inflammation and ferroptosis probably through regulating of Nrf2/HO-1, MAPK and NF-κB signaling pathways.

[Study on effect of Hypericum perforatum on pharmacokinetics of zedoary turmeric oil in compound antiviral preparation].

OBJECTIVE: To study zedoary turmeric oil (ZTO) and the pharmacokinetics of its homemade compound antiviral preparation in New Zealand rabbits. METHOD: RP-HPLC was used to determinate the content of germacrone in rabbit plasma after oral administration. RESULT: After oral administration of ZTO and its homemade compound antiviral preparation, the plasma concentration-time curve of germacrone is in conformity to two-compartment open model. The pharmacokinetic parameters of ZTO: t1/2alpha, t1/2beta, Vd, CL, AUC and Ka were (1.52 +/- 0.59), (1.97 +/- 0.27) h, (47.59 +/- 2.29) L x kg(-1), (176.77 +/- 7.65) L x h(-1) x kg(-1), (5.70 +/- 0.70) mg x h x L(-1) and (0.97 +/- 0.11) h(-1), respectively, while those of compound preparation were (0.41 +/- 0.03), (1.47 +/- 0.35) h, (75.21 +/- 5.21) L x kg(-1), (287.79 +/- 6.39) L x h(-1) x kg(-1), (3.91 +/- 0.53) mg x h x L(-1) and (5.14 +/- 1.26) h(-1), respectively. There was no significant difference between the above two groups of pharmacokinetic parameters, expect that Ka of compound preparation was significantly higher than that of ZTO (P < 0.05). CONCLUSION: Hypericum perforatum in compound preparation doesn't impact the distribution and elimination of active ingredients of ZTO in New Zealand rabbits, but it improves the absorption speed, and shortens the time of drug absorption, which contributes to rapid efficacy of ZTO in rabbits.

Construction and characterization of a recombinant human beta defensin 2 fusion protein targeting the epidermal growth factor receptor: in vitro study.

The HER2/neu proto-oncogene encodes a 185-kDa trans-membrane glycoprotein kinase with extensive homology to the epidermal growth factor receptor and plays a key role in the transformation and growth of malignant tumors. To date, two antibody drugs targeting HER2/neu have been developed successfully. In order to reduce the cost and the time of clinical treatment, we produced a fusion protein composed of human beta defensin 2 (hBD2) and anti-HER2/neu single-chain variable fragment (scFv 4D5), which is capable of specifically targeting, significantly inhibiting, and promptly killing HER2/neu-positive cancer cells. The recombinant protein was expressed in Escherichia coli using the small ubiquitin-related modifier (SUMO) as the molecular chaperone, and the optimal expression level reached to 40.2 % of the total supernatant protein. After purifying by Ni-NTA affinity chromatography, the fusion protein was cleaved with a SUMO-specific protease to obtain hBD2-4D5, which was further purified by Ni-NTA affinity chromatography. The purity of hBD2-4D5 was higher than 95 %, and the yield was 19 ± 2 mg/L in flask fermentation. The cell number count and flow cytometry results showed that hBD2-4D5 exerted cytotoxic and anti-proliferative effects on HER2/neu-positive breast cancer cell line, SKBR-3. The results of scanning electron microscope and transmission electron microscope observation indicated that hBD2-4D5 could induce intracellular ultrastructure changes and cell necrosis by disrupting the cell membrane. Immunofluorescence analysis showed that hBD2-4D5 could bind to SKBR-3 cells and further be internalized into the cytoplasm. Moreover, hBD2-4D5 could also mediate apoptosis of SKBR-3 cells by up-regulating the ratio of Bax to Bcl-2.

Dihydrolipoamide dehydrogenase and cAMP are associated with cadmium-mediated Leydig cell damage.

Cadmium (Cd) directly inhibits testosterone production in Leydig cells, but its mechanism is still unclear. To further explore the signaling pathway of Cd-mediated toxicity to Leydig cells, various concentrations of Cd were cultured with R2C cells for 24h, and two-dimensional gel electrophoresis (2DE)-based proteomics profiling was used to analyze the change of protein expressions. Cd caused a concentration-dependent inhibition of cell viability with IC(25), IC(50) and IC(75) of 2.42×10(-5)M, 4.83×10(-5)M and 7.39×10(-5)M, respectively. Cd significantly reduced progesterone production and mitochondrial membrane potential (ΔΨ(m)) in a concentration-dependent manner. 2DE-based proteomics showed 34 protein spots with altered expression by 2-folds or more, and dihydrolipoamide dehydrogenase (DLD) was the hub in the network of these altered proteins. Real-time polymerase chain reaction (PCR) and Western blotting showed that Cd downregulated the expression of DLD. Cd also decreased intracellular levels of cyclic adenosine monophosphate (cAMP). The results suggest that DLD and cAMP may be key elements related to Cd toxicity to Leydig cells.