THE EFFECTS OF ALPHA SYNUCLEIN OVEREXPRESSION ON NEUROTROPHIC FACTORS AND THEIR RECEPTORS IN HUMAN PRIMARY ASTROCYTE CULTURE

Abstract

Astrocytes are support cells in central nervous system (1). Together with the other neuroglial cells, these cells produce neurotransmitters, hormones, trophic and immune factors and participate in synaptic functions in various stages of development (2). α-synucleinopathies are a group of neurodegenerative disorders which are characterized with abnormal accumulation of α-synuclein protein in the cytoplasm of neurons and glia cells (3). α-synuclein has a role in dopamine release, memory formation and cognitive functions. α-synuclein may also affect the synaptic activity by acting as a chaperone and may be needed in neurotransmitter release in presynaptic nerve terminals (4). Impairment of calcium homeostasis and alterations in synthesis and utilization of neurotrophic factors take part in the most significant common pathological mechanisms of neurodegenerative disorders which also includes α-synucleinopathies (5). Present study was designed in order to determine the general profile of human astrocytes in terms of neurotrophic factor synthesis and secretion, and how this profile is altered in response to α-synuclein overexpression. In the study, the primary human astrocytes was cultured. Human SNCA gene carrying plasmid was transferred to the cells by using a lipid-based transfection agent. Levels of more than 40 intracellular and released trophic factors or their receptors in untreated and α-synuclein overexpressing astrocytes were detected with chemiluminescence-based western/dot blot method by using human growth factor antibody array. Our preliminary results shows that some of the factors from VEGF, PDGF, FGF, EGF class, TGF-β3 from TGF class and NT-4 from neurotrophin class predominately produced, while bNGF is produced low and FGF-4 has nearly no expression in untreated astrocytes. α-synuclein overexpression in astrocytes highly altered the profile described above. This is the first study that investigated the general profile of intracellular and released neurotrophic factors and their receptors in human astrocytes and how this profile is altered by α-synuclein overexpression. (The present work was supported by the Research Fund of Istanbul University, Project no: 23616 and by the Scientific and Technological Research Council of Turkey-TUBITAK, Project no: 216S887.)