title: AKAP-dependent modulation of BCAM/Lu adhesion on normal and sickle cell disease RBCs revealed by force nanoscopy.
abstract: Human normal and sickle red blood cells (RBCs) adhere with high affinity to the alpha5 chain of laminin (LAMA5) via the basal cell adhesion molecule/Lutheran (BCAM/Lu) receptor, which is implicated in vasoocclusive episodes in sickle cell disease and activated through the cyclic adenosine monophosphate (cAMP) signaling pathway. However, the effect of the cAMP pathway on the expression of active BCAM/Lu receptors at the single-molecule level is unknown. We established an in vitro technique, based on atomic force microscopy, which enables detection of single BCAM/Lu proteins on the RBC surface and measures the unbinding force between BCAM/Lu and LAMA5. We showed that the expression of active BCAM/Lu receptors is higher in homozygous sickle RBCs (SS-RBCs) than normal RBCs and that it is critically dependent on the cAMP signaling pathway on both normal and SS-RBCs. Of importance, we illustrated that A-kinase anchoring proteins are crucial for BCAM/Lu receptor activation. Furthermore, we found that SS-RBCs from hydroxyurea-treated patients show a lower expression of active BCAM/Lu receptors, a lower unbinding force to LAMA5, and insignificant stimulation by epinephrine as compared to SS-RBCs from untreated patients. To our knowledge, these findings may lead to novel antiadhesive targets for vasoocclusive episodes in sickle cell disease.
authors.affiliation: Department of Biomedical Engineering, University of Connecticut, Storrs, Connecticut; Department of Hematology, Division of Experimental Hematology, St. Jude Children's Research Hospital, Memphis, Tennessee.
authors.forename: Jamie L
authors.initials: JL
authors.lastname: Maciaszek
authors.affiliation: Adult Sickle Cell Center, University of Connecticut Health Center, Farmington, Connecticut.
authors.forename: Biree
authors.initials: B
authors.lastname: Andemariam
authors.affiliation: Department of Biomedical Engineering, University of Connecticut, Storrs, Connecticut.
authors.forename: Krithika
authors.initials: K
authors.lastname: Abiraman
authors.affiliation: Department of Biomedical Engineering, University of Connecticut, Storrs, Connecticut; Department of Mechanical Engineering, University of Connecticut, Storrs, Connecticut. Electronic address: gelyko@engr.uconn.edu.
authors.forename: George
authors.initials: G
authors.lastname: Lykotrafitis
mesh_terms: D054758:A Kinase Anchor Proteins / Q000378:metabolism*; D000328:Adult; D000755:Anemia, Sickle Cell / Q000378:metabolism*; D016022:Case-Control Studies; D015815:Cell Adhesion Molecules / Q000378:metabolism*; D000242:Cyclic AMP / Q000378:metabolism; D004912:Erythrocytes / Q000378:metabolism* / Q000648:ultrastructure; D006801:Humans; D007797:Laminin / Q000378:metabolism; D008188:Lutheran Blood-Group System / Q000378:metabolism*; D018625:Microscopy, Atomic Force / Q000379:methods; D011485:Protein Binding
chemical_list: D054758:A Kinase Anchor Proteins; C090228:BCAM protein, human; D015815:Cell Adhesion Molecules; D007797:Laminin; D008188:Lutheran Blood-Group System; C097043:laminin alpha5; D000242:Cyclic AMP