TY - JOUR

T1 - Cholesterol stabilization of phospholipid vesicles against bile-induced solubilization

AU - Tai, Patrick

AU - Clulow, Andrew J.

AU - Boyd, Ben J.

AU - Golding, Matt

AU - Singh, Harjinder

AU - Everett, David W.

N1 - Funding Information: This research project was funded in part by the Riddet Institute Center of Research Excellence (CoRE) through the Tertiary Education Commission of New Zealand . This research was undertaken on the SAXS/WAXS beamline at the Australian Synchrotron, part of the Australian Nuclear Science and Technology Organization (ANSTO) through merit beamtime proposal: AS2/SAXS/16276 . The shipping of samples from Palmerston North, New Zealand to Clayton, Victoria, Australia was funded by the New Zealand Synchrotron Group (NZSG). Funding Information: This research project was funded in part by the Riddet Institute Center of Research Excellence (CoRE) through the Tertiary Education Commission of New Zealand. This research was undertaken on the SAXS/WAXS beamline at the Australian Synchrotron, part of the Australian Nuclear Science and Technology Organization (ANSTO) through merit beamtime proposal: AS2/SAXS/16276. The shipping of samples from Palmerston North, New Zealand to Clayton, Victoria, Australia was funded by the New Zealand Synchrotron Group (NZSG).

PY - 2023

Y1 - 2023

N2 - Sphingomyelin (SM) and cholesterol complex to form functional liquid-ordered (Lo) domains. It has been suggested that the detergent resistance of these domains plays a key role during gastrointestinal digestion of the milk fat globule membrane (MFGM), which is rich in both SM and cholesterol. Small-angle X-ray scattering was employed to determine the structural alterations that occur when milk sphingomyelin (MSM)/cholesterol, egg sphingomyelin (ESM)/cholesterol, soy phosphatidylcholine (SPC)/cholesterol, and milk fat globule membrane (MFGM) phospholipid/cholesterol model bilayer systems were incubated with bovine bile under physiological conditions. The persistence of diffraction peaks was indicative of multilamellar vesicles of MSM with cholesterol concentrations > 20 % mol, and also for ESM with or without cholesterol. The complexation of ESM with cholesterol is therefore capable of inhibiting the resulting vesicles from disruption by bile at lower cholesterol concentrations than MSM/cholesterol. After subtraction of background scattering by large aggregates in the bile, a Guinier fitting was used to determine changes in the radii of gyration (Rgs) over time for the biliary mixed micelles after mixing the vesicle dispersions with bile. Swelling of the micelles by phospholipid solubilization from vesicles was a function of cholesterol concentration, with less swelling of the micelles occurring as the cholesterol concentration was increased. With 40% mol cholesterol, the Rgs of the bile micelles mixed with MSM/cholesterol, ESM/cholesterol, and MFGM phospholipid/cholesterol were equal to the control (PIPES buffer + bovine bile), indicating negligible swelling of the biliary mixed micelles.

AB - Sphingomyelin (SM) and cholesterol complex to form functional liquid-ordered (Lo) domains. It has been suggested that the detergent resistance of these domains plays a key role during gastrointestinal digestion of the milk fat globule membrane (MFGM), which is rich in both SM and cholesterol. Small-angle X-ray scattering was employed to determine the structural alterations that occur when milk sphingomyelin (MSM)/cholesterol, egg sphingomyelin (ESM)/cholesterol, soy phosphatidylcholine (SPC)/cholesterol, and milk fat globule membrane (MFGM) phospholipid/cholesterol model bilayer systems were incubated with bovine bile under physiological conditions. The persistence of diffraction peaks was indicative of multilamellar vesicles of MSM with cholesterol concentrations > 20 % mol, and also for ESM with or without cholesterol. The complexation of ESM with cholesterol is therefore capable of inhibiting the resulting vesicles from disruption by bile at lower cholesterol concentrations than MSM/cholesterol. After subtraction of background scattering by large aggregates in the bile, a Guinier fitting was used to determine changes in the radii of gyration (Rgs) over time for the biliary mixed micelles after mixing the vesicle dispersions with bile. Swelling of the micelles by phospholipid solubilization from vesicles was a function of cholesterol concentration, with less swelling of the micelles occurring as the cholesterol concentration was increased. With 40% mol cholesterol, the Rgs of the bile micelles mixed with MSM/cholesterol, ESM/cholesterol, and MFGM phospholipid/cholesterol were equal to the control (PIPES buffer + bovine bile), indicating negligible swelling of the biliary mixed micelles.

KW - Detergent kinetics

KW - in vitro digestion

KW - Milk fat globule membrane

KW - Phospholipid

KW - Small angle X-ray scattering

U2 - 10.1016/j.chemphyslip.2023.105289

DO - 10.1016/j.chemphyslip.2023.105289

M3 - Journal article

C2 - 36813145

AN - SCOPUS:85149267231

VL - 252

JO - Chemistry and Physics of Lipids

JF - Chemistry and Physics of Lipids

SN - 0009-3084

M1 - 105289

ER -