Dr. Cronstein has received consulting fees (less than $10,000 each) from King Pharmaceuticals, CanFite Biopharmaceuticals, Bristol-Myers Squibb, Cellzome, Tap Pharmaceuticals, Prometheus Laboratories, Regeneron (data safety and monitoring [Westat]), Sepracor, Amgen, Endocyte, and Protalex and has received honoraria or speaking fees (less than $10,000 each) from Tap Pharmaceuticals and Amgen. He owns stock in CanFite Biopharmaceuticals. He holds patents on use of adenosine A2A receptor antagonists to promote wound healing and to inhibit fibrosis, on testing for single-nucleotide polymorphisms in the adenosine A1 receptor to treat fibromyalgia, and on use of the adenosine A1 receptor to treat osteoporosis and other diseases of bone.
The antiinflammatory mechanism of methotrexate depends on extracellular conversion of adenine nucleotides to adenosine by ecto-5′-nucleotidase: Findings in a study of ecto-5′-nucleotidase gene–deficient mice
Version of Record online: 27 APR 2007
Copyright © 2007 by the American College of Rheumatology
Arthritis & Rheumatism
Volume 56, Issue 5, pages 1440–1445, May 2007
How to Cite
Montesinos, M. C., Takedachi, M., Thompson, L. F., Wilder, T. F., Fernández, P. and Cronstein, B. N. (2007), The antiinflammatory mechanism of methotrexate depends on extracellular conversion of adenine nucleotides to adenosine by ecto-5′-nucleotidase: Findings in a study of ecto-5′-nucleotidase gene–deficient mice. Arthritis & Rheumatism, 56: 1440–1445. doi: 10.1002/art.22643
- Issue online: 27 APR 2007
- Version of Record online: 27 APR 2007
- Manuscript Accepted: 16 FEB 2007
- Manuscript Received: 28 NOV 2006
- Ramón y Cajal Program of the Spanish Ministry of Education and Science
- Valencian Government (Conselleria d'EmpresaUniversitat i Ciència). Grant Number: GV05/031
- Instituto de Salud Carlos III. Grant Number: FIS 05/1659
- NIH. Grant Numbers: AI-18220, AR-41911, GM-56268, AA-13336
- Spanish Ministry of Education and Science
- General Clinical Research Center. Grant Number: M01-RR-00096
- King Pharmaceuticals
- Kaplan Cancer Center
Evidence from in vitro, in vivo, and clinical studies indicates that adenosine mediates, at least in part, the antiinflammatory effects of methotrexate (MTX), although the biochemical events involved have not been fully elucidated. This study was undertaken to investigate whether MTX exerts antiinflammatory effects in mice that lack ecto-5′-nucleotidase (ecto-5′-NT) (CD73) and are unable to convert AMP to adenosine extracellularly, in order to determine whether adenosine is generated intracellularly and transported into the extracellular space or is generated from the extracellular dephosphorylation of AMP to adenosine.
Male CD73 gene–deficient mice and age-matched wild-type mice received intraperitoneal injections of saline or MTX (1 mg/kg/week) for 5 weeks. Air pouches were induced on the back by subcutaneous injection of air; 6 days later, inflammation was induced by injection of carrageenan.
Fewer leukocytes, but higher levels of tumor necrosis factor α (TNFα), accumulated in the air pouches of vehicle-treated CD73-deficient mice compared with those of wild-type mice. As expected, MTX treatment reduced the number of leukocytes and TNFα levels in the exudates and increased exudate adenosine concentrations in wild-type mice. In contrast, MTX did not reduce exudate leukocyte counts or TNFα levels or increase exudate adenosine levels in CD73-deficient mice.
These results demonstrate that the antiinflammatory actions of MTX are mediated, at least in part, by increased release of adenine nucleotides that are hydrolyzed extracellularly to adenosine via an ecto-5′-NT–dependent pathway.