Olivera, AnaMetcalfe, Dean D.Kastner, Daniel L.Boyden, Steven E.Komarow, Hirsh D.Tobío Ageitos, AraceliSmelkinson, Margery G.Bai, YunBandara, GeethaniNaranjo, Andrea N.2024-01-222024-01-222020Naranjo, A.N., Bandara, G., Bai, Y., Smelkinson, M.G., Tobío, A. Komarow, H.D., Boyden, S.E., Kastner, D.L., Metcalfe, D.D., Olivera, A. (2020). Critical Signaling Events in the Mechanoactivation of Human Mast Cells through p.C492Y-ADGRE2. Journal of Investigative Dermatology, 140 (11), pp 2210-2220.e50022-202Xhttp://hdl.handle.net/10347/31927A role for the adhesion G-protein coupled receptor ADGRE2 or EMR2 in mechanosensing was revealed by the finding of a missense substitution (p.C492Y) associated with familial vibratory urticaria. In these patients, friction of the skin induces mast cell hyper-degranulation through p.C492Y-ADGRE2, causing localized hives, flushing, and hypotension. We have now characterized the responses and intracellular signals elicited by mechanical activation in human mast cells expressing p.C492Y-ADGRE2 and attached to dermatan sulfate, a ligand for ADGRE2. The presence of p.C492Y-ADGRE2 reduced the threshold to activation and increased the extent of degranulation along with the percentage of mast cells responding. Vibration caused phospholipase C activation, transient increases in cytosolic calcium, and downstream activation of phosphoinositide 3-kinase and extracellular signaleregulated kinases 1 and 2 by Gbg, Gaq/11, and Gai/o-independent mechanisms. Degranulation induced by vibration was dependent on phospholipase C pathways, including calcium, protein kinase C, and phosphoinositide 3-kinase but not extracellular signaleregulated kinases 1/2 pathways, along with pertussis toxin-sensitive signals. In addition, mechanoactivation of mast cells stimulated the synthesis and release of prostaglandin D2, to our knowledge a previously unreported mediator in vibratory urticaria, and extracellular signaleregulated kinases 1/2 activation was required for this response together with calcium, protein kinase C, and to some extent, phosphoinositide 3-kinase. Our studies thus identified critical molecular events initiated by mechanical forces and potential therapeutic targets for patients with vibratory urticaria.engAttribution-NonCommercial-NoDerivs 4.0 International (CC BY-NC-ND 4.0)http://creativecommons.org/licenses/by-nc-nd/4.0/journal article10.1016/j.jid.2020.03.936open access