ABNORMALITIES IN CELL SIGNALING AND RED CELL PATHOLOGIES

Red blood cells (RBCs) are enucleated cells specialized in delivering oxygen to body tissues. RBC membrane organization, which is characterized by phospholipids and cholesterol bilayer, containing integral membrane proteins such as band 3 that links RBC membrane to the alpha-beta spectrin based cytoskeleton network through two multiprotein complexes. The ankyrin and band 4.1 multiprotein complexes bridge the membrane to the skeleton ensuring the dynamic changes and membrane mechanical stability required by the permanence of RBC in the peripheral circulation. Post-translational modifications (PTMs), such as phosphorylation, might rapidly modulate protein conformational state and interactions with neighbor proteins. Changes in either tyrosine (Tyr) or serine/threonine (Ser/Thr) protein phosphorylation state, through modulation of kinases and/or phosphatases, are involved in membrane functions such as cell volume regulation, membrane mechanical stability or membrane ion transport function. The aim of the present research work is to analyze signaling pathways involved in red cell proteostasis. We studied two different models of diseased red cells: 1) Red cells from patients with chronic C hepatitis undergoing to triplice anti-viral therapy 2) Red cells from a mouse model genetically lacking Fyn, a tyrosine kinase of the Src family kinase, which recapitulate red cell features of G6PD deficient erythrocytes Our results demonstrate that: - Triplice therapy induced an acquired spherocytic like anemia with increased phosphorylation of beta-adducin, worsened by ineffective erythropoiesis due to possible toxic effect of triplice therapy on erythropoiesis. - Fyn is involved in activation of G6PD. Future studies will be design to further characterize: - The role of protease inhibitors and red cell homeostasis since anemia is a major limitation of this therapeutic approach. - The role of Fyn in G6PD/NADP/Thioredoxin reductase pathway towards Prx2 in both mouse and human red cells.