Assessing Flavonoid-Membrane Interactions in Model Lipid Bilayers Using GUVs and Complementary Biophysical Approaches

• Grant number: 26/01483-5
• Support Opportunities: Scholarships abroad - Research Internship - Scientific Initiation
• Start date: April 20, 2026
• End date: July 19, 2026
• Field of knowledge: Biological Sciences - Biology
• Principal Investigator: Karina Alves de Toledo
• Grantee: Arissa Yonamine
• Supervisor: Jonathan Richard Brewer
• Host Institution: Faculdade de Ciências e Letras (FCL-ASSIS). Universidade Estadual Paulista (UNESP). Campus de Assis. Assis , SP, Brazil
• Institution abroad: University of Southern Denmark (SDU), Denmark
• Associated to the scholarship: 24/09875-4 - Molecular interactions of flavonoids Jaceosidin and Kaempferol 7 O-neohesperidoside in cell membrane model systems, extracted from HEp-2 cells, BP.IC

Abstract

Human Respiratory Syncytial Virus (hRSV), belonging to the Orthopneumovirus genus, is a major cause of severe acute respiratory infections, especially in children, the elderly, and immunocompromised individuals, resulting in high morbidity and mortality rates. Despite ongoing efforts, currently available prophylactic and therapeutic strategies, such as the use of Ribavirin, monoclonal antibodies, and vaccines, still have specific limitations in terms of efficacy, cost, and population coverage, particularly for the most vulnerable groups. In recent years, our research group has dedicated itself to investigating compounds with antiviral potential against hRSV, with an emphasis on natural molecules such as flavonoids. Previous studies conducted within the scope of FAPESP projects (2023/02743-2 and 2024/09875-4) revealed that the flavonoids Jaceosidin and Kaempferol-7-O-neohesperidoside were able to protect Hep-2 cells from hRSV infection in different experimental protocols. Biophysical analysis of the interaction of these compounds with model lipid monolayers revealed that both insert into the lipid interface, promoting changes in membrane packing without significantly modifying its compaction level (FAPESP 2024/09875-4). Furthermore, Jaceosidin was observed to have membrane stabilizing capacity, possibly conferring protection against oxidative damage by reactive oxygen species, while Kaempferol-7-O-neohesperidoside did not demonstrate alterations in membrane stability. However, extrapolating these results to lipid bilayer systems requires more complex and physiologically relevant experimental models. In this context, the present project aims to investigate the interaction of the flavonoids jaceosidin and kaempferol with model lipid bilayers, using giant unilamellar vesicles (GUVs) composed of DOPC and DOPS. Flavonoid-membrane interactions will be evaluated using complementary membrane biophysics techniques. Assays using the Laurdan fluorescent probe will allow the evaluation of changes in the degree of ordering and fluidity of the lipid bilayer. In addition, confocal fluorescence microscopy will be used to investigate the location, distribution, and interaction dynamics of flavonoids in the membrane, taking advantage of their intrinsic fluorescence. (AU)