Lipid domain coarsening and fluidity in multicomponent lipid vesicles: A continuum based model and its experimental validation

Wang, Y.; Palzhanov, Yerbol; Quaini, Annalisa; Olshanskii, Maxim A.; Majd, Sheereen

doi:10.1016/j.bbamem.2022.183898

Cited by 6 publications

(14 citation statements)

References 44 publications

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“…Examining the phase-separated GUVs of 1:2:1 composition revealed a similar effect for DOPA and DOTAP on the L o domain area fraction (Figure B). In the absence of these charged lipids, the average area fraction of L o phase on GUVs with this ternary composition was 0.69, which is in agreement with the theoretically estimated value of 0.70 based on phase-diagrams, as detailed in our previous study . Partial replacement of DOPC with DOPA or DOTAP led to an increase in L o domain area fraction where, for instance, it reached ∼ 0.85 for 15 mol % DOPA and ∼0.77 for 15 mol % DOTAP.…”

Section: Results and Discussionsupporting

confidence: 91%

“…In the absence of these charged lipids, the average area fraction of L o phase on GUVs with this ternary composition was 0.69, which is in agreement with the theoretically estimated value of 0.70 based on phasediagrams, as detailed in our previous study. 11 Partial replacement of DOPC with DOPA or DOTAP led to an increase in L o domain area fraction where, for instance, it reached ∼ 0.85 for 15 mol % DOPA and ∼0.77 for 15 mol % DOTAP. It should be noted that area fraction measurements proved to be challenging for this composition as the green fluorescence signal was weak and the area fraction analysis was performed based on the red fluorescence signal, which labeled the minority phase in this composition, resulting in higher levels of variations.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

“…GUVs imaging and analysis were performed as described before. , In brief, an imaging chamber was created by sandwiching a frame of double-sided tape between a clean microscope glass slide and a coverslip; 12 μL of GUV solution was sealed in the chamber for imaging. An inverted Zeiss microscopy, Zeiss LSM 800 confocal laser scanning microscope (Zeiss, Germany) equipped with epifluorescence, was used to monitor and image the membrane phase-behavior in GUVs.…”

Section: Methodsmentioning

confidence: 99%

“…For domain area fraction calculations, we assumed that the GUVs were spherical in shape and their domains were in the form of spherical caps. Confocal images of GUVs were analyzed to find the diameter and area of domains as detailed in our previous studies. , The analysis was performed on at least 10 GUVs from 3 independent experiments for all compositions except 25 mol % DOTAP, 50 mol % DPPC, and 25 mol % Chol with 0.3 mol % Rho-PE and 0.5 mol % NAP.…”

Section: Methodsmentioning

confidence: 99%

“…Phase separation affects the organization of membrane molecules and is thus, involved in a wide range of cellular functions such as vesicle trafficking, , cell adhesion, and metabolic processes . As a result, membrane phase separation has been the subject of much research using variety of model membranes. − These studies have revealed that factors such as lipid chain-length, sterol concentration, and concentration of membrane proteins and membrane-bound polymers can influence the lipid phase separation in membranes. Moreover, few studies have demonstrated that negatively charged lipids can impact the membrane phase behavior. − For instance, Dimova and her colleagues reported that in a ternary composition of DOPC:eSM:Chol, replacement of DOPC with negatively charged DOPG led to changes in its phase diagram and shifted the miscibility transition temperature of this mixture to lower temperatures.…”

Section: Introductionmentioning

confidence: 99%

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Charged Lipids Modulate the Phase Separation in Multicomponent Membranes

Wang

Majd

2023

Langmuir

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Phase separation in lipid membranes controls the organization of membrane components and thus regulates membrane-mediated processes. Membrane phase behavior is influenced by the molecular properties of its components and their relative concentrations. Charged lipid species are among the most essential components of lipid membranes, and their impact on the membrane phase behavior is yet to be fully understood. Aiming to provide insight into this impact, this paper investigates how the presence and amount of anionic and cationic lipids affect the phase behavior of multicomponent membranes. Membranes of ternary composition DOPC:DPPC:Chol with two distinct molar ratios were used to test the hypothesis that inclusion of charged lipids with saturated tails, beyond a certain concentration, would impede phase separation in an otherwise phase-separating membrane. Fluorescence microscopy examination of electroformed giant liposomes revealed that when more than half of DOPC in the examined mixtures was replaced with DOPA or DOTAP, phase separation in liposomes was somewhat suppressed, and this effect increased with increasing charged lipid content. This effect depended on the membrane surface charge density as the half-maximal effect was observed at around 0.0072 C Å −2 in all examined cases. The phase-separation suppressing effect of DOPA was neutralized when oppositely charged lipid DOTAP was included in the mixture. Likewise, presence of divalent cation Ca 2+ in the solution neutralized the impact of negatively charged DOPA. These results underline the detrimental influence of surface charge density on membrane phase behavior. More importantly, these findings suggest that the charged lipid content in membranes may be a regulator of their phase behavior and open new opportunities for the design of synthetic lipid membranes.

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Section: Results and Discussionsupporting

confidence: 91%

Section: ■ Results and Discussionmentioning

confidence: 99%