Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:1.17.3.2 (xanthine oxidase)
 8,383 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Hypoxia-inducible factor-1 alpha (HIF-1 alpha) is a master regulator to sense decreased oxygen partial pressure. HIF-1 alpha stability regulation initiates a complex biological response that allows cells to act appropriately to meet patho-physiological situations of decreased oxygen availability. Recently, nitric oxide emerged as a messenger with the ability to stabilize HIF-1 alpha and to transactivate HIF-1 under normoxia. Considering that reactive nitrogen species are recognized for post-translation protein modifications, among others S-nitrosation, we asked whether HIF-1 alpha is a target for S-nitrosation. In vitro NO+ donating NO donors such as GSNO and SNAP provoked massive S-nitrosation of purified HIF-1 alpha. All 15 free thiol groups found in human HIF-1 alpha are subjected to S-nitrosation. Thiol modification is not shared by spermine-NONOate, a NO radical donating compound. However, spermine-NONOate in the presence of O(2)(-), generated by xanthine/xanthine oxidase, regained S-nitrosation, most likely via formation of a N(2)O(3)-like species. In vitro, S-nitrosation of HIF-1 alpha was attenuated by the addition of GSH or ascorbate. In RCC4 and HEK293 cells GSNO or SNAP reproduced S-nitrosation of HIF-1 alpha, however with a significantly reduced potency that amounted to modification of three to four thiols, only. Importantly, endogenous formation of NO in RCC4 cells via inducible NO synthase elicited S-nitrosation of HIF-1 alpha that was sensitive to inhibition of inducible NO synthase activity with N-monomethyl-L-arginine. NO-stabilized HIF-1 alpha was susceptible to the addition of N-acetyl-cysteine that destabilized HIF-1 alpha in close correlation to the disappearance of S-nitrosated HIF-1 alpha. In conclusion, HIF-1 alpha is a target for S-nitrosation by exogenously and endogenously produced NO.
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PMID:HIF-1 alpha protein as a target for S-nitrosation. 1256 87

Endometrial hyperplasia (EH) is a medical condition that affects many females as it increases their uterine carcinogenic potential. EH results from entangling hormonal imbalance and inflammatory response. The study examined the role of a xanthine oxidase inhibitor, febuxostat, in a rat model of EH. Adult female Wistar albino rats were subjected to estradiol valerate (EV) 2 mg/kg for 10 days to induce EH. Another group was treated concomitantly with febuxostat 10 mg/kg for the same period. The uterine malondialdehyde, reduced glutathione (GSH), and superoxide dismutase (SOD) were assessed by chemical methods. Gene expressions of phosphatidylinositol-3-kinase (PI3K), Akt, and hypoxia-inducible factor 1 alpha were assessed by the quantitative real-time polymerase chain reaction. Moreover, the vascular endothelial growth factor (VEGF) and interleukin-6 (IL-6) were measured by enzyme-linked immunosorbent assay. Histopathology and immunohistochemical techniques were used for the detection of phosphatase and tensin homolog (PTEN). The results revealed that EV administration induced complex EH with focal atypia and loss of PTEN expression by the histological examination. Uteri of the EV group showed a significant drop in GSH content and SOD activity and rise in the expressions of PI3K, Akt, VEGF, and IL-6. Febuxostat administration significantly improved the uterine GSH and SOD levels. It decreased the expressions of PI3K, Akt, VEGF, and IL-6. The endometrium showed a regression of the proliferative epithelium with the restoration of PTEN expression and the absence of the atypical features. In conclusion, febuxostat protected the endometrium against estrogen-induced EH and may be beneficial in the management along with the hormonal therapy.
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PMID:PTEN/PI3K/VEGF signaling pathway involved in the protective effect of xanthine oxidase inhibitor febuxostat against endometrial hyperplasia in rats. 3222 92