title: Lysophosphatidic acid induced red blood cell aggregation in vitro.
abstract: Under physiological conditions healthy RBCs do not adhere to each other. There are indications that RBCs display an intercellular adhesion under certain (pathophysiological) conditions. Therefore we investigated signaling steps starting with transmembrane calcium transport by means of calcium imaging. We found a lysophosphatidic acid (LPA) concentration dependent calcium influx with an EC(50) of 5 μM LPA. Downstream signaling was investigated by flow cytometry as well as by video-imaging comparing LPA induced with "pure" calcium mediated phosphatidylserine exposure and concluded the coexistence of two branches of the signaling pathway. Finally we performed force measurements with holographic optical tweezers (HOT): The intercellular adhesion of RBCs (aggregation) exceeds a force of 25 pN. These results support (i) earlier data of a RBC associated component in thrombotic events under certain pathophysiological conditions and (ii) the concept to use RBCs in studies of cellular adhesion behavior, especially in combination with HOT. The latter paves the way to use RBCs as model cells to investigate molecular regulation of cellular adhesion processes.
authors: Institute for Molecular Cell Biology, School of Medicine, Saarland University, Homburg/Saar, Germany. lars_kaestner@me.com
authors: Lars
authors: L
authors: Kaestner
authors: Patrick
authors: P
authors: Steffen
authors: Duc Bach
authors: DB
authors: Nguyen
authors: Jue
authors: J
authors: Wang
authors: Lisa
authors: L
authors: Wagner-Britz
authors: Achim
authors: A
authors: Jung
authors: Christian
authors: C
authors: Wagner
authors: Ingolf
authors: I
authors: Bernhardt
mesh_terms: D002118:Calcium / Q000378:metabolism*; D020013:Calcium Signaling / Q000187:drug effects*; D002448:Cell Adhesion / Q000187:drug effects; D002449:Cell Aggregation / Q000187:drug effects; D002478:Cells, Cultured; D004912:Erythrocytes / Q000166:cytology / Q000187:drug effects*; D005434:Flow Cytometry; D006801:Humans; D017136:Ion Transport / Q000187:drug effects; D007700:Kinetics; D008246:Lysophospholipids / Q000494:pharmacology*; D008856:Microscopy, Fluorescence; D057054:Molecular Imaging; D052898:Optical Tweezers; D010718:Phosphatidylserines / Q000737:chemistry / Q000378:metabolism
chemical_list: D008246:Lysophospholipids; D010718:Phosphatidylserines; C032881:lysophosphatidic acid; D002118:Calcium