guanosine-triphosphate and Arthritis--Rheumatoid

The mechanism of anti-inflammatory effects of methotrexate (MTX) at low dose may relate to a decrease in availability of the purine precursor or it may depend on accumulation of 5-aminoimidazole-4-carboxamide (AICAR) and the anti-inflammatory nucleoside adenosine. The aim of this study was to evaluate the possible mechanism of action by analysis of changes in blood concentrations of purine and pyrimidine metabolites during MTX treatment.. Venous blood samples were collected from rheumatoid arthritis patients before and at different times for up to 7 days after the start of MTX treatment. Whole blood concentrations of adenosine, uridine, hypoxanthine, uric acid and erythrocyte nucleotides were measured by HPLC.. The initial blood adenosine concentration was 0.073 +/- 0.013 microM and no differences were observed during MTX treatment. However, a decrease in uric acid concentration was observed from 205.5+/-13.5 to 160. 9+/-13.5 microM (P<0.05) within 24 h after MTX administration. The hypoxanthine concentration decreased in parallel with uric acid, while the uridine concentration decreased 48 h after MTX administration. No accumulation of AICAR-triphosphate (ZTP) was observed in the erythrocytes.. MTX decreases circulating purine and pyrimidine concentrations, and their availability for DNA and RNA synthesis, which may affect immune cell proliferation and protein (cytokine) expression. The absence of adenosine concentration changes and lack of ZTP formation is evidence against an AICAR/adenosine mechanism, although localized adenosine concentration changes cannot be excluded.

Topics: Adenosine; Adenosine Triphosphate; Adult; Aminoimidazole Carboxamide; Antirheumatic Agents; Arthritis, Rheumatoid; Chromatography, High Pressure Liquid; Chronic Disease; Cytidine Triphosphate; Erythrocytes; Female; Guanosine Triphosphate; Humans; Hypoxanthine; Methotrexate; Middle Aged; Ribonucleotides; Uric Acid; Uridine

This study investigated the impacts of SIRT1 activation on rheumatoid arthritis (RA)-related angiogenesis.. HUVECs were cultured by different human serum. Intracellular metabolites were quantified by UPLC-MS. Next, HUVECs and rat vascular epithelial cells under different inflammatory conditions were treated by a SIRT1 agonist resveratrol (RSV). Cytokines and biochemical indicators were detected by corresponding kits. Protein and mRNA expression levels were assessed by immunoblotting and PCR methods, respectively. Angiogenesis capabilities were evaluated by migration, wound-healing and tube-formation experiments. To down-regulate certain signals, gene-specific siRNA were applied.. Metabolomics study revealed the accelerated glycolysis in RA serum-treated HUVECs. It led to ATP accumulation, but did not affect GTP levels. RSV inhibited pro-angiogenesis cytokines production and glycolysis in both the cells, and impaired the angiogenesis potentials. These effects were mimicked by an energy metabolism interrupter bikini in lipopolysaccharide (LPS)-primed HUVECs, largely independent of HIF-1α. Both RSV and bikinin can inhibit the activation of the GTP-dependent pathway Rho/ROCK and reduce VEGF production. Abrogation of RhoA signaling reinforced HIF-1α silencing-brought changes in LPS-stimulated HUVECs, and overshadowed the anti-angiogenesis potentials of RSV.. Glycolysis provides additional energy to sustain Rho/ROCK activation in RA subjects, which promotes VEGF-driven angiogenesis and can be inhibited by SIRT1 activation.

Topics: Animals; Arthritis, Rheumatoid; Chromatography, Liquid; Cytokines; Glycolysis; Guanosine Triphosphate; Humans; Hypoxia-Inducible Factor 1, alpha Subunit; Lipopolysaccharides; Neovascularization, Pathologic; Rats; Resveratrol; Sirtuin 1; Tandem Mass Spectrometry; Vascular Endothelial Growth Factor A