The A2B adenosine receptor protects against inflammation and excessive vascular adhesion

• Published in: The Journal of clinical investigation 2006-07, Vol.116 (7), p.1913-1923
• Main Authors: Yang, Dan, Zhang, Ying, Nguyen, Hao G, Koupenova, Milka, Chauhan, Anil K, Makitalo, Maria, Jones, Matthew R, St Hilaire, Cynthia, Seldin, David C, Toselli, Paul, Lamperti, Edward, Schreiber, Barbara M, Gavras, Haralambos, Wagner, Denisa D, Ravid, Katya
• Format: Article
• Language: English
• Subjects: Animals; Applied Geology; Blood Vessels - cytology; Blood Vessels - physiology; Bone Marrow Cells - cytology; Bone Marrow Cells - physiology; Bone Marrow Transplantation; Cell Adhesion - physiology; Cytokines - metabolism; E-Selectin - metabolism; Female; Genes, Reporter; Inflammation - metabolism; Intercellular Adhesion Molecule-1 - metabolism; Leukocyte Rolling; Mice; Mice, Knockout; P-Selectin - metabolism; Receptor, Adenosine A2B - genetics; Receptor, Adenosine A2B - metabolism; Signal Transduction - physiology; Tillämpad geologi
• ISSN: 0021-9738; 1558-8238
• DOI: 10.1172/jci27933

Adenosine has been described as playing a role in the control of inflammation, but it has not been certain which of its receptors mediate this effect. Here, we generated an A2B adenosine receptor-knockout/reporter gene-knock-in (A2BAR-knockout/reporter gene-knock-in) mouse model and showed receptor gene expression in the vasculature and macrophages, the ablation of which causes low-grade inflammation compared with age-, sex-, and strain-matched control mice. Augmentation of proinflammatory cytokines, such as TNF-alpha, and a consequent downregulation of IkappaB-alpha are the underlying mechanisms for an observed upregulation of adhesion molecules in the vasculature of these A2BAR-null mice. Intriguingly, leukocyte adhesion to the vasculature is significantly increased in the A2BAR-knockout mice. Exposure to an endotoxin results in augmented proinflammatory cytokine levels in A2BAR-null mice compared with control mice. Bone marrow transplantations indicated that bone marrow (and to a lesser extent vascular) A2BARs regulate these processes. Hence, we identify the A2BAR as a new critical regulator of inflammation and vascular adhesion primarily via signals from hematopoietic cells to the vasculature, focusing attention on the receptor as a therapeutic target.