title: Epinephrine-induced activation of LW-mediated sickle cell adhesion and vaso-occlusion in vivo.
abstract: Sickle red cell (SS RBC) adhesion is believed to contribute to the process of vaso-occlusion in sickle cell disease (SCD). We previously found that the LW RBC adhesion receptor can be activated by epinephrine to mediate SS RBC adhesion to endothelial alphavbeta3 integrin. To determine the contribution of LW activation to vaso-occlusive events in vivo, we investigated whether in vitro treatment of SS RBCs by epinephrine resulted in vaso-occlusion in intact microvasculature after RBC infusion into nude mice. Epinephrine enhanced human SS but not normal RBC adhesion to murine endothelial cells in vitro and to endothelium in vivo, promoting vaso-occlusion and RBC organ sequestration. Murine sickle RBCs also responded to epinephrine with increased adhesion to postcapillary endothelium in nude mice. Epinephrine-induced SS RBC adhesion, vaso-occlusion, and RBC organ trapping could be prevented by the beta-adrenergic receptor (beta-AR) antagonist, propranolol. Infusion of soluble recombinant LW also significantly reduced adhesion and vaso-occlusion. In addition, epinephrine-treated SS RBCs induced activation of murine leukocyte adhesion to endothelium as well. We conclude that LW activation by epinephrine via beta-AR stimulation can promote both SS RBC and leukocyte adhesion as well as vaso-occlusion, suggesting that both epinephrine and LW play potentially pathophysiological roles in SCD.
authors.affiliation: Division of Hematology and Duke Comprehensive Sickle Cell Center, Department of Medicine, Duke University Medical Center, Durham, NC 27710, USA.
authors.forename: Rahima
authors.initials: R
authors.lastname: Zennadi
authors.forename: Benjamin J
authors.initials: BJ
authors.lastname: Moeller
authors.forename: Erin J
authors.initials: EJ
authors.lastname: Whalen
authors.forename: Milena
authors.initials: M
authors.lastname: Batchvarova
authors.forename: Ke
authors.initials: K
authors.lastname: Xu
authors.forename: Siqing
authors.initials: S
authors.lastname: Shan
authors.forename: Martha
authors.initials: M
authors.lastname: Delahunty
authors.forename: Mark W
authors.initials: MW
authors.lastname: Dewhirst
authors.forename: Marilyn J
authors.initials: MJ
authors.lastname: Telen
mesh_terms: D000755:Anemia, Sickle Cell / Q000378:metabolism / Q000473:pathology*; D000818:Animals; D002448:Cell Adhesion / Q000187:drug effects; D015815:Cell Adhesion Molecules / Q000378:metabolism*; D002470:Cell Survival; D002478:Cells, Cultured; D004727:Endothelium / Q000098:blood supply / Q000187:drug effects / Q000473:pathology; D004837:Epinephrine / Q000494:pharmacology*; D004912:Erythrocytes / Q000166:cytology / Q000187:drug effects; D006801:Humans; D007962:Leukocytes / Q000166:cytology / Q000187:drug effects / Q000276:immunology; D051379:Mice; D008819:Mice, Nude; D018343:Receptors, Adrenergic, beta-2 / Q000378:metabolism
chemical_list: D015815:Cell Adhesion Molecules; C095100:ICAM4 protein, human; D018343:Receptors, Adrenergic, beta-2; D004837:Epinephrine