Membrane elasticity modulated by cholesterol in model of porcine eye lens-lipid membrane

Khadka, Nawal K.; Mortimer, Max-Florian; Marosvari, Mason; Timsina, Raju; Mainali, Laxman

doi:10.1016/j.exer.2022.109131

Cited by 7 publications

(6 citation statements)

References 129 publications

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“…Approximately 360 μL of warm (~50 °C) buffer (3.6 mM HEPES, 36 mM NaCl, pH = 7.4) was added to ~75 μL chloroform mixture. The rapid solvent exchange (RSE) method [ 129 , 130 , 131 ] was used to prepare the large multilamellar vesicles (LMVs), as described previously [ 132 , 133 ]. Briefly, the glass tube containing warm buffer and chloroform mixture was placed on the vortexer and connected to the sample manifold of the RSE equipment.…”

Section: Methodsmentioning

confidence: 99%

Binding of Alpha-Crystallin to Cortical and Nuclear Lens Lipid Membranes Derived from a Single Lens

Timsina

Wellisch

Haemmerle

et al. 2022

IJMS

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Several studies reported that α-crystallin concentrations in the eye lens cytoplasm decrease with a corresponding increase in membrane-bound α-crystallin with age and cataracts. The influence of the lipid and cholesterol composition difference between cortical membrane (CM) and nuclear membrane (NM) on α-crystallin binding to membranes is still unclear. This study uses the electron paramagnetic resonance (EPR) spin-labeling method to investigate the α-crystallin binding to bovine CM and NM derived from the total lipids extracted from a single lens. Compared to CMs, NMs have a higher percentage of membrane surface occupied by α-crystallin and binding affinity, correlating with less mobility and more order below and on the surface of NMs. α-Crystallin binding to CM and NM decreases mobility with no significant change in order and hydrophobicity below and on the surface of membranes. Our results suggest that α-crystallin mainly binds on the surface of bovine CM and NM and such surface binding of α-crystallin to membranes in clear and young lenses may play a beneficial role in membrane stability. However, with decreased cholesterol content within the CM, which mimics the decreased cholesterol content in the cataractous lens membrane, α-crystallin binding increases the hydrophobicity below the membrane surface, indicating that α-crystallin binding forms a hydrophobic barrier for the passage of polar molecules, supporting the barrier hypothesis in developing cataracts.

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Section: Methodsmentioning

confidence: 99%

Binding of Alpha-Crystallin to Cortical and Nuclear Lens Lipid Membranes Derived from a Single Lens

Timsina

Wellisch

Haemmerle

et al. 2022

IJMS

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“…PC content, as normalized to the total lipid content, was also unaffected (Supplementary Figure S3 D). To further analyze the membrane properties of CM EVs, we applied AFM measurements, as cholesterol affects the rigidity, banding and elasticity of plasma membranes 26 – 28 .…”

Section: Resultsmentioning

confidence: 99%

Effect of hypercholesterolemia on circulating and cardiomyocyte-derived extracellular vesicles

Kovácsházi,

Hambalkó,

Sayour

et al. 2024

Sci Rep

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Hypercholesterolemia (HC) induces, propagates and exacerbates cardiovascular diseases via various mechanisms that are yet not properly understood. Extracellular vesicles (EVs) are involved in the pathomechanism of these diseases. To understand how circulating or cardiac-derived EVs could affect myocardial functions, we analyzed the metabolomic profile of circulating EVs, and we performed an in-depth analysis of cardiomyocyte (CM)-derived EVs in HC. Circulating EVs were isolated with Vezics technology from male Wistar rats fed with high-cholesterol or control chow. AC16 human CMs were treated with Remembrane HC supplement and EVs were isolated from cell culture supernatant. The biophysical properties and the protein composition of CM EVs were analyzed. THP1-ASC-GFP cells were treated with CM EVs, and monocyte activation was measured. HC diet reduced the amount of certain phosphatidylcholines in circulating EVs, independently of their plasma level. HC treatment significantly increased EV secretion of CMs and greatly modified CM EV proteome, enriching several proteins involved in tissue remodeling. Regardless of the treatment, CM EVs did not induce the activation of THP1 monocytes. In conclusion, HC strongly affects the metabolome of circulating EVs and dysregulates CM EVs, which might contribute to HC-induced cardiac derangements.

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“…Once dried, ~360 µL of warm (~50 • C) buffer (0.55 mM HEPES, pH = 7.4) was added to the evaporated chloroform mixture. The rapid solvent exchange (RSE) method [162][163][164][165] was then used to prepare large multilamellar vesicles (LMVs) [165,166]. RSE is done by placing the buffer-chloroform mixture containing tube on a vortexer and connecting the tube to the sample manifold of the RSE equipment.…”

Section: Preparation Of Small Unilamellar Vesicles (Suvs) From Cortic...mentioning

confidence: 99%

Association of Alpha-Crystallin with Human Cortical and Nuclear Lens Lipid Membrane Increases with the Grade of Cortical and Nuclear Cataract

Hazen,

Trossi-Torres,

Timsina

et al. 2024

IJMS

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Eye lens α-crystallin has been shown to become increasingly membrane-bound with age and cataract formation; however, to our knowledge, no studies have investigated the membrane interactions of α-crystallin throughout the development of cataracts in separated cortical membrane (CM) and nuclear membrane (NM) from single human lenses. In this study, four pairs of human lenses from age-matched male and female donors and one pair of male lenses ranging in age from 64 to 73 years old (yo) were obtained to investigate the interactions of α-crystallin with the NM and CM throughout the progression of cortical cataract (CC) and nuclear cataract (NC) using the electron paramagnetic resonance spin-labeling method. Donor health history information (diabetes, smoker, hypertension, radiation treatment), sex, and race were included in the data analysis. The right eye lenses CM and NM investigated were 64 yo male (CC: 0), 68 yo male (CC: 3, NC: 2), 73 yo male (CC: 1, NC: 2), 68 yo female (CC: 3, NC: 2), and 73 yo female (CC: 1, NC: 3). Similarly, left eye lenses CM and NM investigated were 64 yo male (CC: 0), 68 yo male (CC: 3, NC: 2), 73 yo male (CC: 2, NC: 3), 68 yo female (CC: 3, NC: 2), and 73 yo female (CC: 1, NC: 3). Analysis of α-crystallin binding to male and female eye lens CM and NM revealed that the percentage of membrane surface occupied (MSO) by α-crystallin increases with increasing grade of CC and NC. The binding of α-crystallin resulted in decreased mobility, increased order, and increased hydrophobicity on the membrane surface in male and female eye lens CM and NM. CM mobility decreased with an increase in cataracts for both males and females, whereas the male lens NM mobility showed no significant change, while female lens NM showed increased mobility with an increase in cataract grade. Our data shows that a 68 yo female donor (long-term smoker, pre-diabetic, and hypertension; grade 3 CC) showed the largest MSO by α-crystallin in CM from both the left and right lens and had the most pronounced mobility changes relative to all other analyzed samples. The variation in cholesterol (Chol) content, size and amount of cholesterol bilayer domains (CBDs), and lipid composition in the CM and NM with age and cataract might result in a variation of membrane surface mobility, membrane surface hydrophobicity, and the interactions of α-crystallin at the surface of each CM and NM. These findings provide insight into the effect of decreased Chol content and the reduced size and amount of CBDs in the cataractous CM and NM with an increased binding of α-crystallin with increased CC and NC grade, which suggests that Chol and CBDs might be a key component in maintaining lens transparency.

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Membrane elasticity modulated by cholesterol in model of porcine eye lens-lipid membrane

Cited by 7 publications

References 129 publications

Binding of Alpha-Crystallin to Cortical and Nuclear Lens Lipid Membranes Derived from a Single Lens

Binding of Alpha-Crystallin to Cortical and Nuclear Lens Lipid Membranes Derived from a Single Lens

Effect of hypercholesterolemia on circulating and cardiomyocyte-derived extracellular vesicles

Association of Alpha-Crystallin with Human Cortical and Nuclear Lens Lipid Membrane Increases with the Grade of Cortical and Nuclear Cataract

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