Ekzozomal miR-34a Aracılığıyla Mikroglia – Nöron Etkileşimi

Microglia are extra-embryonic yolk sac-derived myeloid cells in the Central Nervous System (CNS) playing roles in regulating brain development, repairing injuries and maintaining neuronal networks. When signaling dangers to CNS by dead cells, microbes, unnecessary synapses and soluble antigens, they remove them and maintain homeostasis. Because of being the primary source of proinflammatory cytokines, microglial cells mediate neuroinflammation and regulate cellular responses that have extensive spectrum. Exosomes are membrane-encapsulated vesicles that are released via various cell types. They have functions in regulating cell-to-cell transmission via carrying their cargo to recipient cells containing microRNAs (miRNAs), mRNAs, proteins and DNA. Microglia-derived exosomes promote neural regeneration by stimulating neurite outgrowth and might have a role in neurological disorders. MiRNAs within exosomes have functional roles when being delivered into the recipient cells and are thought to be the key functional elements. The aim of this thesis is to identify the impacts of microglial cells on neuronal cells via exosomal miR-34a. As a requirement of this purpose, SH-SY5Y neuronal cell line will be treated with different concentrations of hydrogen peroxide (H2O2) and its cytotoxicity will be evaluated via LDH (Lactate Dehydrogenase) assay and PI (Propidium Iodide) visualization. Then, the cytotoxic effect of hydrogen peroxide on neurite outgrowth will be determined by assessing the number of protrusions per cell, and neurite lengths will be analyzed and expressed as mean process length. After that, HMC3 microglial cell line will be transfected with miR-34a mimic and their exosomes will be given to SH-SY5Y cells. The impacts of miR-34a on SH-SY5Y cells in terms of neuroprotection will be determined.