Differential expression of adenosine receptors in human endothelial cells: role of A2B receptors in angiogenic factor regulation.
Adenosine has been reported to stimulate or inhibit the release of angiogenic factors depending on the cell type examined. To test the hypothesis that differential expression of adenosine receptor subtypes contributes to endothelial cell heterogeneity, we studied microvascular (HMEC-1) and umbilical vein (HUVEC) human endothelial cells. Based on mRNA level and stimulation of adenylate cyclase, we found that HUVECs preferentially express A2A adenosine receptors and HMEC-1 preferentially express A2B receptors. Neither cells expressed A1 or A3 receptors. The nonselective adenosine agonist 5'-N-ethylcarboxamidoadenosine (NECA) increased expression of interleukin-8 (IL-8), basic fibroblast growth factor (bFGF), and vascular endothelial growth factor (VEGF) in HMEC-1, but had no effect in HUVECs. In contrast, the selective A2A agonist 2-p-(2-carboxyethyl)phenylethylamino-NECA (CGS 21680) had no effect on expression of these angiogenic factors. Cotransfection of each type of adenosine receptors with a luciferase reporter in HMEC-1 showed that A2B receptors, but not A1, A2A, or A3, activated IL-8 and VEGF promoters. These effects were mimicked by constitutively active alphaG(q), alphaG12, and alphaG13, but not alphaG(s) or alphaG(i1-3). Furthermore, stimulation of phospholipase C indicated coupling of A2B receptors to G(q) proteins in HMEC-1. Thus, differential expression of adenosine receptor subtypes contributes to functional heterogeneity of human endothelial cells. A2B receptors, predominantly expressed in human microvascular cells, modulate expression of angiogenic factors via coupling to G(q), and possibly via G12/13.
Feoktistov
Igor
I
Division of Cardiology, Vanderbilt University, Nashville, Tenn 37232-6300, USA. igor.feoktistov@mcmail.vanderbilt.edu
Goldstein
Anna E
AE
Ryzhov
Sergey
S
Zeng
Dewan
D
Belardinelli
Luiz
L
Voyno-Yasenetskaya
Tatyana
T
Biaggioni
Italo
I
D000262:Adenylyl Cyclases / Q000378:metabolism; D043925:Angiogenesis Inducing Agents / Q000378:metabolism*; D000818:Animals; D016466:CHO Cells; D006224:Cricetinae; D016228:Endothelial Growth Factors / Q000235:genetics; D004730:Endothelium, Vascular / Q000166:cytology / Q000378:metabolism*; D017930:Genes, Reporter; D020962:Heterotrimeric GTP-Binding Proteins / Q000235:genetics / Q000378:metabolism; D006801:Humans; D007295:Inositol Phosphates / Q000378:metabolism; D016209:Interleukin-8 / Q000235:genetics; D008156:Luciferases / Q000235:genetics; D008222:Lymphokines / Q000235:genetics; D008833:Microcirculation / Q000378:metabolism; D018919:Neovascularization, Physiologic / Q000502:physiology; D011401:Promoter Regions, Genetic / Q000502:physiology; D058906:Purinergic P1 Receptor Agonists; D012333:RNA, Messenger / Q000378:metabolism; D043705:Receptor, Adenosine A2A; D043704:Receptor, Adenosine A2B; D018047:Receptors, Purinergic P1 / Q000096:biosynthesis* / Q000235:genetics; D015290:Second Messenger Systems / Q000502:physiology; D014162:Transfection; D042461:Vascular Endothelial Growth Factor A; D042442:Vascular Endothelial Growth Factors; D014680:Veins / Q000378:metabolism
D043925:Angiogenesis Inducing Agents; D016228:Endothelial Growth Factors; D007295:Inositol Phosphates; D016209:Interleukin-8; D008222:Lymphokines; D058906:Purinergic P1 Receptor Agonists; D012333:RNA, Messenger; D043705:Receptor, Adenosine A2A; D043704:Receptor, Adenosine A2B; D018047:Receptors, Purinergic P1; D042461:Vascular Endothelial Growth Factor A; D042442:Vascular Endothelial Growth Factors; D008156:Luciferases; D020962:Heterotrimeric GTP-Binding Proteins; D000262:Adenylyl Cyclases