Lipid Hydroperoxide Compromises the Membrane Structure Organization and Softens Bending Rigidity

Author(s)

Scanavachi, Gustavo ^{[1, 2, 3]} ; Coutinho, Ana ^{[4, 5]} ; Fedorov, Alexander Andreevich ^{[4, 5]} ; Prieto, Manuel ^{[4, 5]} ; Melo, Ana M. ^{[4, 5]} ; Itri, Rosangela ^[1]

Affiliation

^[1] Univ Sao Paulo, Inst Phys, BR-05508090 Sao Paulo - Brazil

^[2] Boston Childrens Hosp, Program Cellular & Mol Med, Boston, MA 02115 - USA

^[3] Harvard Med Sch, Dept Cell Biol, Boston, MA 02115 - USA

^[4] Univ Lisbon, iBB Inst Bioengn & Biosci, Inst Super Tecn, P-1049001 Lisbon - Portugal

^[5] Univ Lisbon, Inst Super Tecn, Associate Lab I4HB, Inst Hlth & Bioecon, P-1049001 Lisbon - Portugal

• Document type: Journal article
• Source: Langmuir; v. 37, n. 33, p. 9952-9963, AUG 24 2021.
• Web of Science Citations: 0

Abstract

Lipid hydroperoxides are key mediators of diseases and cell death. In this work, the structural and dynamic perturbations induced by the hydroperoxidized POPC lipid (POPC-OOH) in fluid POPC membranes, at both 23 and 37 degrees C, were addressed using advanced small-angle X-ray scattering (SAXS) and fluorescence methodologies. Notably, SAXS reveals that the hydroperoxide group decreases the lipid bilayer bending rigidity. This alteration disfavors the bilayer stacking and increases the swelling inbetween stacked bilayers. We further investigated the changes in the apolar/ polar interface of hydroperoxide-containing membranes through timeresolved fluorescence/anisotropy experiments of the probe TMA-DPH and time-dependent fluorescence shifts of Laurdan. A shorter mean fluorescence lifetime for TMA-DPH was obtained in enriched POPC-OOH membranes, revealing a higher degree of hydration near the membrane interface. Moreover, a higher microviscosity near TMA-DPH and lower order are predicted for these oxidized membranes, at variance with the usual trend of variation of these two parameters. Finally, the complex relaxation process of Laurdan in pure POPC-OOH membranes also indicates a higher membrane hydration and viscosity in the close vicinity of the -OOH moiety. Altogether, our combined approach reveals that the hydroperoxide group promotes alterations in the membrane structure organization, namely, at the level of membrane order, viscosity, and bending rigidity. (AU)

• FAPESP's process: 14/20107-7 - Lipid oxidation in membrane and cell biophysics: from functional nanosensors to impact on amyloid formation. Application of advanced fluorescence, X-ray scattering and microscopy techniques
• Grantee: Rosangela Itri
• Support Opportunities: Regular Research Grants