AUTHOR=Guarnieri Joseph W. , Angelin Alessia , Murdock Deborah G. , Schaefer Patrick , Portluri Prasanth , Lie Timothy , Huang Jessica , Wallace Douglas C. 

TITLE=SARS-COV-2 viroporins activate the NLRP3-inflammasome by the mitochondrial permeability transition pore

JOURNAL=Frontiers in Immunology

VOLUME=Volume 14 - 2023

YEAR=2023

URL=https://www.frontiersin.org/journals/immunology/articles/10.3389/fimmu.2023.1064293

DOI=10.3389/fimmu.2023.1064293

ISSN=1664-3224

ABSTRACT=Cytokine storm is a major cause of COVID19 death. To elucidate how SARS-CoV2 initiates this inflammatory process, we studied viroporin proteins E and Orf3a (2-E+2-3a). Expression of 2-E+2-3a in 293T cells increased cytosolic Ca++ and elevated mitochondrial Ca++, taken up through the MCUi11-sensitive mitochondrial calcium uniporter. Increased mitochondrial Ca++ stimulated NADH and mitochondrial reactive oxygen species (mROS) production, which was blocked by mitochondrially-targeted catalase or MnTBAP. To determined how mROS activates the inflammasome, we reconstituted the mitochondrially-bound NLRP3-inflammasome in 293T cells and used THP1 derived macrophages to monitor the secretion of mature interleukin (IL)-1β. This revealed that mROS activates the release of mitochondrial DNA via the NIM811-sensitive mitochondrial permeability pore (mtPTP), activating the inflammasome. Hence, interventions targeting mROS and the mtPTP may mitigate the severity of COVID19 cytokine storms.