Homocysteine modifies extracellular ATP availability in macrophages

• Published in: Toxicology in vitro Vol. 27; no. 8; pp. 2273 - 2278
• Main Authors: Zanin, Rafael Fernandes, Bergamin, Letícia Scussel, Braganhol, Elizandra, Sévigny, Jean, de Souza Wyse, Angela Terezinha, Battastini, Ana Maria Oliveira
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.12.2013
• Subjects: adenosine; adenosine diphosphate; adenosine monophosphate; Adenosine Triphosphatases - genetics; adenosine triphosphate; Adenosine Triphosphate - metabolism; Animals; anti-inflammatory activity; Apyrase - genetics; coronary artery disease; Ecto-5′-nucleotidase; enzymes; Homocysteine; Homocysteine - pharmacology; hydrolysis; immune response; inflammation; Macrophages; Macrophages, Peritoneal - drug effects; Macrophages, Peritoneal - metabolism; Male; metabolites; Mice; Mice, Mutant Strains; NTPDase; pathogenesis; protein synthesis; Pyrophosphatases - genetics; reactive oxygen species; Receptors, Purinergic P1 - genetics; Receptors, Purinergic P2 - genetics; RNA, Messenger - metabolism; thrombosis; FBS; HHcy; CAD; ADO; Homocysteine; Macrophages; Ecto-5′-nucleotidase; NTPDase; Hcy; coronary artery disease; hyperhomocysteinemia; ectonucleoside triphosphate diphosphohydrolases; adenosine; fetal bovine serum
• ISSN: 0887-2333; 1879-3177; 1879-3177
• DOI: 10.1016/j.tiv.2013.09.001

•Increased ATP hydrolysis to adenosine by macrophages exposed to homocysteine.•Macrophages Hcy-treated decreased the inosine formation.•Adenosine generated during Hcy treatment probably is uptaken. Increased levels of plasma homocysteine (hyperhomocysteinemia-HHcy) are associated to the development of coronary artery disease (CAD), peripheral vascular disease and thrombosis. In addition, recent studies have shown that inflammation, probably mediated by macrophages, mediates the pathogenesis associated to high levels of homocysteine (Hcy). In the present study, we evaluated the Hcy effects in the ATP hydrolysis and its breakdown products in murine macrophages. The results showed that micromolar concentrations of Hcy increased the ATP, ADP and AMP hydrolysis. Additionally, our results show decreased inosine levels in the extracellular milieu of Hcy-exposed macrophages. The increasing in ATP, ADP and AMP hydrolysis are not explained by increased transcription or protein expression of NTPDases and ecto-5′-nucleotidase (ecto-5′-NT/CD73) enzymes. Moreover, the formation of reactive oxygen species did not interfere in the Hcy effects, which suggest that Hcy or Hcy metabolites act directly on the modulation of NTPDases and ecto-5′-NT/CD73 activities. In conclusion, Hcy induces the rapid breakdown of ATP, ADP and AMP to adenosine (ADO), which is classically known as an anti-inflammatory response in immune cells. However, by the action of these enzymes, the extracellular adenosine generated during Hcy treatment probably is uptaken into the cells, as evidenced by the decreased in inosine formation, and thus collaborating to the inflammatory complications associates to HHcy