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Studies of the physicochemical and mechanical properties of erythrocytes membranes from healthy and with hereditary spherocytosis subjects

Grant number: 15/09948-2
Support type:Scholarships in Brazil - Post-Doctorate
Effective date (Start): October 01, 2015
Effective date (End): September 30, 2018
Field of knowledge:Biological Sciences - Biophysics - Molecular Biophysics
Principal Investigator:Karin Do Amaral Riske
Grantee:Bruna Renata Casadei Buzolin
Home Institution: Escola Paulista de Medicina (EPM). Universidade Federal de São Paulo (UNIFESP). Campus São Paulo. São Paulo , SP, Brazil

Abstract

The erythrocyte membrane is a great model for the study of biological membranes because it is easy to obtain, isolate and to monitor the destabilization (hemolysis) of its structure. Even though its composition and function are well known, there are few reports about the relationship between the organization of its components, structure stability and function. Defects in the erythrocyte membrane include hereditary spherocytosis (HS), a congenital hemolytic anemia caused by a deficiency in cytoskeletal (±- or ²- spectrin, ankyrin and protein 4.2) or integral protein (band 3). Deficiency of these proteins destabilizes the lipid bilayer and, consequently, the erythrocyte membrane assumes a spherical shape and low surface area, which reduces its traffic in the microcirculation, facilitating increased oxidative stress and hemolysis. To understand the complex behavior of proteins and lipids in membranes and their involvement in the stability and organization of its structure, we will use giant unilamellar vesicles (GUVs) and liposomal vesicles composed of erythrocyte membranes of normal individuals and HS, lipid extracts of erythrocyte membrane and biomimetic lipid compositions to obtain information on the physicochemical and mechanical properties of the membranes. Moreover, the protective effect of antioxidants (±-tocopherol and p-coumaric acid) and solubilization by detergents will be investigated. For this, we will use the biophysical techniques of optical microscopy by phase contrast and fluorescence, eletrodeformation and electroporation, light scattering (DLS), tracking of vesicles (NTA) and electron paramagnetic resonance (EPR).