The effect of inflammation and post-inflamatory administration of n-acetylcysteine on LAG3 and TLR2 receptors of H4 cells in the cellular (in vitro) model of parkinson's disease

. Parkinson's disease is a complex, multifactorial neurodegenerative disease that has prevalence of 1% over the age of 55. Pathological hallmarks of Parkinson's disease include the loss of dopaminergic neurons in the substantia nigra pars compacta and the accumulation of inclusion bodies that contain predominantly alpha-synuclein (α-syn) and ubiquitinated proteins, called Lewy bodies. Although the formation of α-syn occurs intracellular, it can also be translocalized to extracellular space and then taken into the other cells via receptor mediated endocytosis. TLR2 is a well known receptor which detects extracellular α-syn and modulates the uptake of the protein by other cells. Uptaken α-syn is known to trigger expression and secretion of inflammatory cytokines such as TNF-α, IL-1β, IL-2 and IL-6 and induce neuroinflammation, apoptosis and mitophagy that results in cellular death. N-Acetylcysteine ​​(NAC), an anti-inflammatory and anti-carcinogenic drug, has gained some focus to circumvent the detrimental effects of neuroinflammatory response. In this thesis, we hypothesized that, NAC treatment will result in anti-inflammatory response that restrict in vitro apoptotic and neuroinflammatory response by modulating transcription and expression of TLR2 and LAG3 receptors. In order to test this hypothesis, WT α-syn overexpressing human neuroglioma (H4) cell line was treated with TNF-α to induce inflammation and NAC, as anti-inflammatory drug to recover from deleterious effects of TNF-α induced inflammation and apoptosis. α-syn protein transcription and expression were validated by q-PCR and Western Blot, respectively. Cell viability was measured by Toxilight assay, and apoptosis was evaluated by Western Blot and TUNEL methods. We observed that NAC treatment diminishes inflammation mediated toxicity and cell death by altering transcription and expression of TLR2 and LAG3 receptors. Thereby, this study demonstrates NAC to be a promising candidate to recover from neuroinflammation that occurs in Parkinson's Disease. Key Words: Parkinson's Disease, Inflammation, Alpha-synuclein (α-syn), N-Acetylcysteine (NAC), Apoptosis Supported by Hacettepe University Scientific Research Projects Coordination Unit (Project ID: THD-2019-18110)