UDP-glucose acting at P2Y14 receptors is a mediator of mast cell degranulation.
UDP-glucose (UDPG), a glycosyl donor in the biosynthesis of carbohydrates, is an endogenous agonist of the G protein-coupled P2Y(14) receptor. RBL-2H3 mast cells endogenously express a P2Y(14) receptor at which UDPG mediates degranulation as indicated by beta-hexosaminidase (HEX) release. Both UDPG and a more potent, selective 2-thio-modified UDPG analog, MRS2690 (diphosphoric acid 1-alpha-d-glucopyranosyl ester 2-[(2-thio)uridin-5''-yl] ester), caused a substantial calcium transient in RBL-2H3 cells, which was blocked by pertussis toxin, indicating the presence of the G(i)-coupled P2Y(14) receptor, supported also by quantitative detection of abundant mRNA. Expression of the closely related P2Y(6) receptor was over 100 times lower than the P2Y(14) receptor, and the P2Y(6) agonist 3-phenacyl-UDP was inactive in RBL-2H3 cells. P2Y(14) receptor agonists also induced [(35)S]GTPgammaS binding to RBL-2H3 cell membranes, and phosphorylation of ERK1/2, P38 and JNK. UDPG and MRS2690 concentration-dependently enhanced HEX release with EC(50) values of 1150+/-320 and 103+/-18nM, respectively. The enhancement was completely blocked by pertussis toxin and significantly diminished by P2Y(14) receptor-specific siRNA. Thus, mast cells express an endogenous P2Y(14) receptor, which mediates G(i)-dependent degranulation and is therefore a potential novel therapeutic target for allergic conditions.
Gao
Zhan-Guo
ZG
Molecular Recognition Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD 20892-0810, USA. ZhanguoG@niddk.nih.gov
Ding
Yi
Y
Jacobson
Kenneth A
KA
D000818:Animals; D002118:Calcium / Q000378:metabolism; D015550:Cell Degranulation / Q000187:drug effects*; D002460:Cell Line; D004789:Enzyme Activation; D019204:GTP-Binding Proteins; D005786:Gene Expression Regulation; D008407:Mast Cells / Q000187:drug effects*; D020929:Mitogen-Activated Protein Kinase Kinases / Q000378:metabolism; D015394:Molecular Structure; D011485:Protein Binding; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D051381:Rats; D011961:Receptors, Fc / Q000235:genetics / Q000378:metabolism; D018048:Receptors, Purinergic P2 / Q000235:genetics / Q000378:metabolism*; D058470:Receptors, Purinergic P2Y; D015398:Signal Transduction; D014532:Uridine Diphosphate Glucose / Q000031:analogs & derivatives* / Q000737:chemistry / Q000494:pharmacology*
C528912:P2Y14 receptor, rat; D012333:RNA, Messenger; D011961:Receptors, Fc; D018048:Receptors, Purinergic P2; D058470:Receptors, Purinergic P2Y; C547289:diphosphoric acid 1-glucopyranosyl ester 2-((2-thio)uridin-5'-yl) ester; D020929:Mitogen-Activated Protein Kinase Kinases; D019204:GTP-Binding Proteins; D002118:Calcium; D014532:Uridine Diphosphate Glucose