title: Morphologically homogeneous red blood cells present a heterogeneous response to hormonal stimulation.
abstract: Red blood cells (RBCs) are among the most intensively studied cells in natural history, elucidating numerous principles and ground-breaking knowledge in cell biology. Morphologically, RBCs are largely homogeneous, and most of the functional studies have been performed on large populations of cells, masking putative cellular variations. We studied human and mouse RBCs by live-cell video imaging, which allowed single cells to be followed over time. In particular we analysed functional responses to hormonal stimulation with lysophosphatidic acid (LPA), a signalling molecule occurring in blood plasma, with the Ca(2+) sensor Fluo-4. Additionally, we developed an approach for analysing the Ca(2+) responses of RBCs that allowed the quantitative characterization of single-cell signals. In RBCs, the LPA-induced Ca(2+) influx showed substantial diversity in both kinetics and amplitude. Also the age-classification was determined for each particular RBC and consecutively analysed. While reticulocytes lack a Ca(2+) response to LPA stimulation, old RBCs approaching clearance generated robust LPA-induced signals, which still displayed broad heterogeneity. Observing phospatidylserine exposure as an effector mechanism of intracellular Ca(2+) revealed an even increased heterogeneity of RBC responses. The functional diversity of RBCs needs to be taken into account in future studies, which will increasingly require single-cell analysis approaches. The identified heterogeneity in RBC responses is important for the basic understanding of RBC signalling and their contribution to numerous diseases, especially with respect to Ca(2+) influx and the associated pro-thrombotic activity.
authors.affiliation: Institute for Molecular Cell Biology and Research Centre for Molecular Imaging and Screening, Saarland University, Homburg/Saar, Germany.
authors.forename: Jue
authors.initials: J
authors.lastname: Wang
authors.forename: Lisa
authors.initials: L
authors.lastname: Wagner-Britz
authors.forename: Anna
authors.initials: A
authors.lastname: Bogdanova
authors.forename: Sandra
authors.initials: S
authors.lastname: Ruppenthal
authors.forename: Kathrina
authors.initials: K
authors.lastname: Wiesen
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Kaiser
authors.forename: Qinghai
authors.initials: Q
authors.lastname: Tian
authors.forename: Elmar
authors.initials: E
authors.lastname: Krause
authors.forename: Ingolf
authors.initials: I
authors.lastname: Bernhardt
authors.forename: Peter
authors.initials: P
authors.lastname: Lipp
authors.forename: Stephan E
authors.initials: SE
authors.lastname: Philipp
authors.forename: Lars
authors.initials: L
authors.lastname: Kaestner
mesh_terms: D000814:Aniline Compounds / Q000494:pharmacology; D000818:Animals; D002118:Calcium / Q000378:metabolism; D004912:Erythrocytes / Q000187:drug effects* / Q000378:metabolism / Q000502:physiology*; D006801:Humans; D008246:Lysophospholipids / Q000494:pharmacology; D051379:Mice; D012156:Reticulocytes / Q000187:drug effects / Q000378:metabolism; D059010:Single-Cell Analysis / Q000379:methods; D014966:Xanthenes / Q000494:pharmacology
chemical_list: D000814:Aniline Compounds; C409648:Fluo 4; D008246:Lysophospholipids; D014966:Xanthenes; C032881:lysophosphatidic acid; D002118:Calcium