Regulation of serotonin-induced trafficking and migration of eosinophils.
Association of the neurotransmitter serotonin (5-HT) with the pathogenesis of allergic asthma is well recognized and its role as a chemoattractant for eosinophils (Eos) in vitro and in vivo has been previously demonstrated. Here we have examined the regulation of 5-HT-induced human and murine Eos trafficking and migration at a cellular and molecular level. Eos from allergic donors and bone marrow-derived murine Eos (BM-Eos) were found to predominantly express the 5-HT2A receptor. Exposure to 5-HT or 2,5-dimethoxy-4-iodoamphetamine (DOI), a 5-HT2A/C selective agonist, induced rolling of human Eos and AML14.3D10 human Eos-like cells on vascular cell adhesion molecule (VCAM)-1 under conditions of flow in vitro coupled with distinct cytoskeletal and cell shape changes as well as phosphorylation of MAPK. Blockade of 5-HT2A or of ROCK MAPK, PI3K, PKC and calmodulin, but not G(αi)-proteins, with specific inhibitors inhibited DOI-induced rolling, actin polymerization and changes in morphology of VCAM-1-adherent AML14.3D10 cells. More extensive studies with murine BM-Eos demonstrated the role of 5-HT in promoting rolling in vivo within inflamed post-capillary venules of the mouse cremaster microcirculation and confirmed that down-stream signaling of 5-HT2A activation involves ROCK, MAPK, PI3K, PKC and calmodulin similar to AML14.3D10 cells. DOI-induced migration of BM-Eos is also dependent on these signaling molecules and requires Ca(2+). Further, activation of 5-HT2A with DOI led to an increase in intracellular Ca(2+) levels in murine BM-Eos. Overall, these data demonstrate that 5-HT (or DOI)/5-HT2A interaction regulates Eos trafficking and migration by promoting actin polymerization associated with changes in cell shape/morphology that favor cellular trafficking and recruitment via activation of specific intracellular signaling molecules (ROCK, MAPK, PI3K and the PKC-calmodulin pathway).
Laboratory of Allergic Diseases and Inflammation, Department of Veterinary and Biomedical Sciences, University of Minnesota, St Paul, Minnesota, United States of America.
Bit Na
BN
Kang
Sung Gil
SG
Ha
Nooshin S
NS
Bahaie
M Reza
MR
Hosseinkhani
Xiao Na
XN
Ge
Malcolm N
MN
Blumenthal
Savita P
SP
Rao
P
P
Sriramarao
D000818:Animals; D002147:Calmodulin / Q000378:metabolism; D002478:Cells, Cultured; D002634:Chemotaxis, Leukocyte / Q000187:drug effects*; D004804:Eosinophils / Q000187:drug effects* / Q000276:immunology* / Q000378:metabolism; D006801:Humans; D036904:Leukocyte Rolling / Q000187:drug effects; D008297:Male; D051379:Mice; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D011493:Protein Kinase C / Q000378:metabolism; D012701:Serotonin / Q000494:pharmacology*; D015398:Signal Transduction; D054460:rho-Associated Kinases / Q000378:metabolism
D002147:Calmodulin; D012701:Serotonin; D019869:Phosphatidylinositol 3-Kinases; D054460:rho-Associated Kinases; D011493:Protein Kinase C; D020928:Mitogen-Activated Protein Kinases