Two-Component Coarse-Grained Molecular-Dynamics Model for the Human Erythrocyte Membrane

Li, He; Lykotrafitis, George

doi:10.1016/j.bpj.2011.11.4012

Cited by 68 publications

(84 citation statements)

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“…Modeling the RBC membrane mechanics remains a challenging task, as multiple length and timescales are involved. Most previous composite models are hence numerical [45][46][47][48] or limited to flat geometries 43,44,[49][50][51]16 . We derive here an active composite membrane model in spherical geometry, while considering explicitly the finite elasticity of the spectrin network and its sliding relative to the bilayer.…”

Section: Main Textmentioning

confidence: 99%

Equilibrium physics breakdown reveals the active nature of red blood cell flickering

et al. 2016

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Section: Main Textmentioning

confidence: 99%

Equilibrium physics breakdown reveals the active nature of red blood cell flickering

et al. 2016

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“…The details of the applied potentials between the lipid CG particles were also discussed in [73,75]. A representation of the potential is plotted as the blue curve in Fig.…”

Section: Model and Simulation Methodsmentioning

confidence: 99%

Vesiculation of healthy and defective red blood cells

Lykotrafitis

2015

Phys. Rev. E

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Vesiculation of mature red blood cells (RBCs) contributes to removal of defective patches of the erythrocyte membrane. In blood disorders, which are related to defects in proteins of the RBC membrane, vesiculation of the plasma membrane is intensified. Several hypotheses have been proposed to explain RBC vesiculation but the exact underlying mechanisms and what determines the sizes of the vesicles are still not completely understood. In this work, we apply a twocomponent coarse-grained molecular dynamics (CGMD) RBC membrane model to study how RBC vesiculation is controlled by the membrane spontaneous curvature and by lateral compression of the membrane. Our simulation results show that the formation of small homogeneous vesicles with a diameter less than 40 nm can be attributed to a large spontaneous curvature of membrane domains. On the other hand, compression on the membrane can cause the formation of vesicles with heterogeneous composition and with sizes comparable with the size of the cytoskeleton corral. When spontaneous curvature and lateral compression are simultaneously considered, the compression on the membrane tends to facilitate formation of vesicles originated from curved membrane domains. We also simulate vesiculation of RBCs with membrane defects connected to hereditary elliptocytosis (HE) and to hereditary spherocytosis (HS). When the vertical connectivity between the lipid bilayer and the membrane skeleton is elevated, as is in normal RBCs, multiple vesicles are shed from the compressed membrane with diameters similar to the cytoskeleton corral size. In HS RBC, where the connectivity between the lipid bilayer and the cytoskeleton is reduced, larger size vesicles are released under the same compression ratio as in normal RBCs. Lastly, we find that vesicles released from HE RBCs can contain cytoskeletal filaments due to fragmentation of the membrane skeleton while vesicles released from the HS RBCs are depleted of cytoskeletal filaments.

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“…In existing whole-cell models, the membrane is usually considered as a single-component shell with effective properties (8)(9)(10) that seek to estimate the combined effects of the lipid bilayer and the spectrin network. In situations where two-component molecular models have been invoked, the computational cost is prohibitively high, such that usually only a small portion of the cell membrane is modeled, a consequence of which is that the wholecell response is not adequately and efficiently captured (11). Furthermore, such models are computationally too inefficient to be amenable to blood microrheology studies involving large numbers of RBCs in flow.…”

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Lipid bilayer and cytoskeletal interactions in a red blood cell

Peng

Pivkin

et al. 2013

Proc. Natl. Acad. Sci. U.S.A.

163

150

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We study the biomechanical interactions between the lipid bilayer and the cytoskeleton in a red blood cell (RBC) by developing a general framework for mesoscopic simulations. We treated the lipid bilayer and the cytoskeleton as two distinct components and developed a unique whole-cell model of the RBC, using dissipative particle dynamics (DPD). The model is validated by comparing the predicted results with measurements from four different and independent experiments. First, we simulated the micropipette aspiration and quantified the cytoskeletal deformation. Second, we studied the membrane fluctuations of healthy RBCs and RBCs parasitized to different intraerythrocytic stages by the malaria-inducing parasite Plasmodium falciparum. Third, we subjected the RBC to shear flow and investigated the dependence of its tank-treading frequency on shear rate. Finally, we simulated the bilayer-cytoskeletal detachment in channel flow to quantify the strength of such interactions when the corresponding bonds break. Taken together, these experiments and corresponding systematic DPD simulations probe the governing constitutive response of the cytoskeleton, elastic stiffness, viscous friction, and strength of bilayer-cytoskeletal interactions as well as membrane viscosities. Hence, the DPD simulations and comparisons with available independent experiments serve as validation of the unique two-component model and lead to useful insights into the biomechanical interactions between the lipid bilayer and the cytoskeleton of the RBC. Furthermore, they provide a basis for further studies to probe cell mechanistic processes in health and disease in a manner that guides the design and interpretation of experiments and to develop simulations of phenomena that cannot be studied systematically by experiments alone.coarse graining | worm-like chain | multiscale modeling | adhesion energy | erythrocyte T he red blood cell (RBC) membrane consists of two components: a lipid bilayer and an attached 2D spectrin network that acts as the cytoskeleton. The resistance of the lipid bilayer to bending is controlled by the bending rigidity, k c , whereas the spectrin network's resistance to shear strain is characterized by the in-plane shear modulus, μ s . Under normal conditions, the cytoskeleton is tightly attached to the lipid bilayer from the cytoplasmic side. However, under certain pathological conditions, e.g., in sickle cell disease, the cytoskeleton may become dissociated from the lipid bilayer (1). Although the biomechanics of the two-component erythrocyte membrane have been studied extensively for decades (2), the mechanical properties of the interactions between the lipid bilayer and the cytoskeleton (such as elastic stiffness, viscous friction, and strength) via the pinning connections of transmembrane proteins are still largely unknown. This is at least in part ascribed to the fact that it is difficult to measure these interactions directly from experiments, because the length scale of these connections is too small compared with the chara...

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Two-Component Coarse-Grained Molecular-Dynamics Model for the Human Erythrocyte Membrane

Cited by 68 publications

References 68 publications

Equilibrium physics breakdown reveals the active nature of red blood cell flickering

Equilibrium physics breakdown reveals the active nature of red blood cell flickering

Vesiculation of healthy and defective red blood cells

Lipid bilayer and cytoskeletal interactions in a red blood cell

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