D‐Galactose‐induced accelerated aging model on human erythrocytes and role of Band 3 protein

Abstract

Aging is a physiological process that induces several changes in cells and tissues, resulting in a greater risk of disease and death. Though this process has been extensively studied both in vivo and in vitro, including human erythrocytes which are an appropriate model to study aging, the involved pathways have not been fully elucidated. D-Galactose (D-Gal) has been widely used in vitro to model the characteristics of premature aging. Nevertheless, there is few information regarding its effect on Band 3 protein (B3p) in human erythrocytes. Band 3 protein is an anion exchanger, essential to maintain homeostasis of erythrocytes and, in turn, of the whole organism. In the present study, human erythrocytes were treated with high D-Gal concentrations (25-35-50-100 mM) for 24 hours at 25°C, and the rate constant for SO42-uptake through B3p was determined to investigate anion exchange capability. As oxidative damage is associated to aging, lipid peroxidation, membrane sulfhydryl oxidation (-SH groups) and % MetHb (methemoglobin) levels after D-Gal treatment were determined. Moreover, % A1c levels (glycated hemoglobin) and expression levels of B3p have been also measured. Our results suggest that D-Gal (35-50-100 mM) reduces anion exchange capability via B3p, putatively mediated both by -SH groups oxidation and lipid peroxidation of cellular membranes; conversely, neither B3p expression levels nor % MetHb were modified. However, D-Gal increased % A1c, known to crosslink with B3p, and involved in the alteration of anion exchange capability. The present findings show that erythrocytes are a good model to study the impact of aging on cell homeostasis. The D-Gal-induced aging model provokes changes at the erythrocyte's membrane level, altering thus anion exchange capability through B3p. High D-Gal concentrations induce elevation of oxidative stress levels, and successively increase % A1c in human erythrocytes. Our findings contribute to the understanding of mechanisms underlying in vitro-induced aging and provide a useful basis for developing therapeutic strategies to counteract age-related diseases and their oxidative impact on erythrocytes. In this view, future studies are recommended to assay antioxidant molecules and their beneficial effect on B3p function during aging process.