SARS-CoV-2 virüsüne karşı hücre bağışıklığında NLRP3 inflamazomunun rölünün belirlenmesi

A new virus named SARS-CoV-2 caused the Covid-19 pandemic. Some patients with severe Covid-19 presented an uncontrolled secretion of cytokines leading to a cytokine storm. Cytokines such as IL-1beta are molecules produced by our immune system. IL- 1beta is activated and secreted by inflammasomes that are cytosolic innate immune receptor recognizing different intracellular pathogens and triggering inflammation and pyroptosis. Recent publications suggest that SARS-CoV-2 infection activates the NLRP3 and AIM2 inflammasomes. However, the molecular mechanism of this activation is unclear. Previous results from our group identified two new SARS-CoV-2 proteins activating inflammasomes. In this thesis, we aimed to characterize whether these two proteins activate the NLRP3 inflammasome. To this aim, we adopted two experimental approaches. Firstly, the inflammasome complex was artificially reconstructed in HEK293FT cells by co-transfection of viral proteins with inflammasome components and IL-1beta activation was monitored by western blotting. Secondly, the binding of the viral proteins activating NLRP3 was predicted by molecular docking. Screening of SARS-CoV-2 proteins showed that besides the already published ORF3a protein, another viral protein activates NLRP3 inflammasome in transfected HEK293FT cells. Molecular docking analyses revealed that this viral protein interacts with the inflammasome receptor. These results indicate that a new SARS-CoV-2 protein activates the NLRP3 inflammasome in our experimental setting. Furthermore, this protein docks with the pyrin domain of the NLRP3 receptor. These findings may contribute to the understanding of the molecular mechanism of Covid-19 and the development of efficient therapies by targeting this protein and the NLRP3 inflammasome.