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NADPH oxidases (NOX) - derived reactive oxygen species (ROS) contribute to oxidative injury in hypoxia-induced pulmonary arterial hypertension. This study aims to evaluate the status of NOX in endothelial progenitor cells (EPCs) under hypoxic condition and to determine whether NOX inhibitors could attenuate hypoxia-induced dysfunctions of EPCs. EPCs were isolated from peripheral blood of SD rats and subjected to hypoxia (O 2 /N 2 /CO 2 , 1/94/5) for 24 h. The cells were collected for β-galactosidase or Hoechst staining, or for functional analysis (migration, adhesion and tube formation). The NOX expression, activity and H 2 O 2 content in EPCs were measured. The results showed that hypoxia treatment promoted EPC senescence and apoptosis, accompanied by the deteriorated functions of EPCs (the reduced abilities in adhesion, migration and tube formation), as well as an increase in NOX2 and NOX4 expression, NOX activity and H 2 O 2 production, these phenomena were attenuated by NOX inhibitors. Furthermore, administration of catalase could also improve the functions of hypoxia-treated EPCs. Based on these observations, we conclude that NOX-derived ROS contributes to the dysfunctions of EPCs under hypoxic condition. Thus, suppression of NOX may provide a novel strategy to improve endothelial functions in hypoxia-relevant diseases. [ABSTRACT FROM AUTHOR]

[Display omitted] • The 7−OH MTX was the main culprit for MTX nephrotoxicity. • PERK/CHOP mediated ER stress was screened as key pathway by RNA-seq analysis. • Nobiletin could ameliorate the nephrotoxicity of 7−OH MTX through PERK/CHOP pathway. • Nobiletin could maintain Ca2+ homeostasis and reduce the production of ROS. Drug-induced nephrotoxicity is a frequent adverse event that contributes to acute kidney injury with tubular and/or glomerular lesions. Methotrexate (MTX) is a folate analog used against a myriad of malignancies and autoimmune diseases. Unfortunately, ambiguous renal toxicology limits its safe clinical usage. Based on our previous studies, 7−OH MTX as an overlooked oxidative metabolite of MTX was proposed to be the main culprit responsible for nephrotoxicity, while nobiletin, a naturally occurring polymethoxylated flavonoid screened from our prepared total phenolic extracts of Citrus aurantium L. (TPE-CA), was employed as a therapeutic agent for drug-drug interactions. According to the present study, nobiletin can ameliorate the renal accumulation of 7−OH MTX through the interaction with aldehyde oxidase. RNA-seq analysis revealed that 7−OH MTX was mainly related to protein processing in endoplasmic reticulum (ER) stress, with the PERK/CHOP pathway selected as the most significant for metabolic nephrotoxicity. Meanwhile, the cross-linked proteins and conducted signals were investigated by western blotting and further verified by GSK inhibition analyses. These results indicated that nobiletin protected renal function from MTX-induced nephrotoxicity by modulating metabolism and ameliorated the metabolic toxicity of 7−OH MTX on ER stress-induced PERK/CHOP conduction by maintaining Ca2+ homeostasis and reducing the production of reactive oxygen species. [ABSTRACT FROM AUTHOR]

Abstract: Exposure to elevated levels of manganese has been shown to cause neuronal damage in the midbrain and the development of Parkinsonian symptoms. Activation of microglia and release of neurotoxic factors in particular free radicals are known to contribute to neurodegeneration. We have recently reported that manganese chloride (MnCl2) stimulates microglia to produce reactive oxygen species (ROS). The aim of this study is to determine the role of microglia in the MnCl2-induced degeneration of dopaminergic (DA) neurons that are particularly vulnerable to oxidative insult. MnCl2 (10–300 μM; 7 days) was markedly more effective in damaging DA neurons in the rat mesencephalic neuron–glia cultures than the neuron-enriched (microglia-depleted) cultures. In addition, the microglia-enhanced MnCl2 toxicity was found to be preferential to DA neurons. The microglial enhancement of DA neurotoxicity was further supported by the observation that replenishment of microglia to the neuron-enriched cultures significantly increased the susceptibility of DA neurons to the MnCl2-induced damage. Analysis of the temporal relationship between microglial activation and DA neurodegeneration revealed that MnCl2-stimulated microglial activation preceded DA neurodegeneration. Mechanistically, MnCl2 (10–300 μM) stimulated a concentration- and time-dependent robust production of ROS and moderate production of nitric oxide but no detectable release of tumor necrosis factor-alpha and interleukin-1beta. Application of free radical scavengers including superoxide dismutase/catalase, glutathione, N-acetyl cysteine and an inhibitor of nitric oxide biosynthesis significantly protected DA neurons against the MnCl2-induced degeneration. These results demonstrate that microglial activation and the production of reactive nitrogen and oxygen free radicals promote the MnCl2-induced DA neurodegeneration. [Copyright &y& Elsevier]