Evaluation of the effect of Miltefosine on membrane curvature

JESSICA VALDIVIA PÉREZ ; LUIS BENITO PÉREZ SOCA; AMBROGGIO, ERNESTO ESTEBAN; FANANI, MARÍA LAURA

Virtual

Congreso; XLIX Reunión Annual SAB; 2021

SOCIEDADA ARGENTINA DE BIOFÍSICA

Miltefosine is an amphiphilic drug originally conceived as an antitumor agent. Nowadays, its use is focused on the treatment of some forms of leishmaniasis and breast cancer metastasis. Although its mechanism of action is not completely known, several studies have demonstrated its influence on cholesterol homeostasis, and the physical properties of biological membranes such as the relaxation of highly curved structures.The aim of our work is to study the effect of miltefosine on highly curved membrane structures. For this, we propose the analysis of two different artificial membrane systems.The first system consisted of using confocal microscopy to observe giant unilamellar vesicles (GUVs) of POPC:GM1 (90:10) that, under specific conditions of electroformation and a ten-fold dilution in HEPES solution, spontaneously exhibit highly curved structures in their interior produced by an area excess in the GUVs? inner leaflet. This allows us to evaluate the effect of miltefosine when added from the outside of the vesicles, showing that the highly curved structures retract due to the incorporation of the drug, causing the recovery of symmetry in the bilayer.The second system is focused on the evaluation of the phase transitions of DOPC:glycerol monooleate (GMO) lipid dispersions, which, in the presence of miltefosine, undergoes a transition from a cubic phase (highly curved structure) to a hexagonal phase, a more relaxed structure. For this purpose, we used the spectral phasors approach to analyze the fluorescence emission spectra of the LAURDAN probe of several DOPC:GMO mixtures and in the presence of the drug. This probe is highly sensitive to its environment and gives information about the lipid's phase state.Overall, our results highlight the occurrence of a scarcely-studied modulation of the membrane physical properties by the incorporation of an amphiphilic drug, opening a new perspective on the manipulation of membrane-modulated cellular processes.This work was funded by SecyT-UNC, FONCyT PICT 2017-0332 and PICT 2019-02331 to MLF and PICT 2015-2575 and PICT 2018-3204 to EEA. EEA and MLF are Career Researchers at CONICET and Professors at UNC. JVP and LBPS are Assistant Professors at FCQ-UNC undergraduate students. LBPS is a fellow of CONICET.