Louise Conrard1, Amaury Stommen1, Anne-Sophie Cloos1, Jan Steinkühler2, Rumiana Dimova2, Hélène Pollet1, Donatienne Tyteca3. 1. CELL Unit, de Duve Institute & Université catholique de Louvain, Brussels, Belgium. 2. Theory and Bio-Systems, Max Planck Institute of Colloids and Interfaces, Science Park Golm, Potsdam, Germany. 3. CELL Unit, de Duve Institute & Université catholique de Louvain, Brussels, Belgiumdonatienne.tyteca@uclouvain.be.
Abstract
BACKGROUND/AIMS: Red blood cells (RBC) have been shown to exhibit stable submicrometric lipid domains enriched in cholesterol (chol), sphingomyelin (SM), phosphatidylcholine (PC) or ganglioside GM1, which represent the four main lipid classes of their outer plasma membrane leaflet. However, whether those lipid domains co-exist at the RBC surface or are spatially related and whether and how they are subjected to reorganization upon RBC deformation are not known. METHODS: Using fluorescence and/or confocal microscopy and well-validated probes, we compared these four lipid-enriched domains for their abundance, curvature association, lipid order, temperature dependence, spatial dissociation and sensitivity to RBC mechanical stimulation. RESULTS: Our data suggest that three populations of lipid domains with decreasing abundance coexist at the RBC surface: (i) chol-enriched ones, associated with RBC high curvature areas; (ii) GM1/PC/chol-enriched ones, present in low curvature areas; and (iii) SM/PC/chol-enriched ones, also found in low curvature areas. Whereas chol-enriched domains gather in increased curvature areas upon RBC deformation, low curvature-associated lipid domains increase in abundance either upon calcium influx during RBC deformation (GM1/PC/chol-enriched domains) or upon secondary calcium efflux during RBC shape restoration (SM/PC/chol-enriched domains). Hence, abrogation of these two domain populations is accompanied by a strong impairment of the intracellular calcium balance. CONCLUSION: Lipid domains could contribute to calcium influx and efflux by controlling the membrane distribution and/or the activity of the mechano-activated ion channel Piezo1 and the calcium pump PMCA. Whether this results from lipid domain biophysical properties, the strength of their anchorage to the underlying cytoskeleton and/or their correspondence with inner plasma membrane leaflet lipids remains to be demonstrated.
BACKGROUND/AIMS: Red blood cells (RBC) have been shown to exhibit stable submicrometric lipid domains enriched in cholesterol (chol), sphingomyelin (SM), phosphatidylcholine (PC) or gangliosideGM1, which represent the four main lipid classes of their outer plasma membrane leaflet. However, whether those lipid domains co-exist at the RBC surface or are spatially related and whether and how they are subjected to reorganization upon RBC deformation are not known. METHODS: Using fluorescence and/or confocal microscopy and well-validated probes, we compared these four lipid-enriched domains for their abundance, curvature association, lipid order, temperature dependence, spatial dissociation and sensitivity to RBC mechanical stimulation. RESULTS: Our data suggest that three populations of lipid domains with decreasing abundance coexist at the RBC surface: (i) chol-enriched ones, associated with RBC high curvature areas; (ii) GM1/PC/chol-enriched ones, present in low curvature areas; and (iii) SM/PC/chol-enriched ones, also found in low curvature areas. Whereas chol-enriched domains gather in increased curvature areas upon RBC deformation, low curvature-associated lipid domains increase in abundance either upon calcium influx during RBC deformation (GM1/PC/chol-enriched domains) or upon secondary calcium efflux during RBC shape restoration (SM/PC/chol-enriched domains). Hence, abrogation of these two domain populations is accompanied by a strong impairment of the intracellular calcium balance. CONCLUSION:Lipid domains could contribute to calcium influx and efflux by controlling the membrane distribution and/or the activity of the mechano-activated ion channel Piezo1 and the calcium pump PMCA. Whether this results from lipid domain biophysical properties, the strength of their anchorage to the underlying cytoskeleton and/or their correspondence with inner plasma membrane leaflet lipids remains to be demonstrated.
Authors: Anne-Sophie Cloos; Marine Ghodsi; Amaury Stommen; Juliette Vanderroost; Nicolas Dauguet; Hélène Pollet; Ludovic D'Auria; Eric Mignolet; Yvan Larondelle; Romano Terrasi; Giulio G Muccioli; Patrick Van Der Smissen; Donatienne Tyteca Journal: Front Physiol Date: 2020-07-03 Impact factor: 4.566
Authors: Anne-Sophie Cloos; Laura G M Daenen; Mauriane Maja; Amaury Stommen; Juliette Vanderroost; Patrick Van Der Smissen; Minke Rab; Jan Westerink; Eric Mignolet; Yvan Larondelle; Romano Terrasi; Giulio G Muccioli; Andra C Dumitru; David Alsteens; Richard van Wijk; Donatienne Tyteca Journal: Front Physiol Date: 2021-02-23 Impact factor: 4.566