Evaluation of the effect of amphiphilic drugs from the Alkylphospholipid family on membrane curvature

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

Rosario

Congreso; L Reunión Anual SAB; 2022

SOCIEDADA ARGENTINA DE BIOFÍSICA

Alkylphospholipids are a family of amphiphilic molecules extensively studied for theireffectiveness as antineoplastic agents, as well as for their antifungal and antimicrobialproperties. It is known that these drugs are capable of interfering with lipid dependentsurvival signaling pathways, intracellular cholesterol traffic and biosynthesis ofphosphatidylcholine (PC) without directly interacting with DNA but rather with theplasma membrane.Our hypothesis is that the amphiphilic drugs Miltefosine, Edelfosine and Perifosine, dueto their conical geometric shape are also able to modulate the spontaneous negativecurvature of membranes by geometric compensation. For this, we propose the analysisof two different artificial membrane systems.The first system consisted of using confocal microscopy to observe the effect of three ofthe drugs in Giant Unilamellar Vesicles (GUVs) obtained by electroformation from aPOPC:GM1 mixture. Under specific conditions of composition, electroformation anddilution these GUVs exhibit highly curved structures (nanotubes). This system willallow us to evaluate the ability of each drug to modulate the spontaneous negativecurvature of the membrane by observing the extent of the symmetry recovery.The second system is focused on the evaluation of the phase transition for DOPC:DOPElipid dispersions, which in the presence of each drug undergoes a transition from aninverted hexagonal phase (HII) (highly curved structure) to a more relaxed structure, aliquid disordered phase (Lα). We used General Polarization (GPex) calculation andspectral phasors to analyze the fluorescence emission spectra of the LAURDAN probe insamples with or without the presence of the drugs.Our results show that Miltefosine and Edelfosine have similar effects on the modulationof negative membrane curvature with Perifosine having the least influence asevidenced by the reduction of the number of vesicles with internal nanotubes by 17.8%, 18.3 % and 7.7 % respectively. This behavior can also be observed with the phasordiagrams, in which Miltefosine and Edelfosine are able to cause a phase transition frominverted hexagonal (HII) to liquid disordered (Lα) with relatively small amounts of bothdrugs but in the case of Perifosine a larger amount of drug was needed to achieve thetransition.