Mechanism of TFEB-mediated proviral and antiviral autophagy during EV-D68 infection

Abstract Enterovirus D68 (EV-D68) is a reemerging pathogen and a significant cause of acute respiratory illness in infants. Recently, infection with EV-D68 has been associated with severe respiratory disease and a neurological condition known as acute flaccid myelitis. There is no prophylactic vaccine or specific antiviral to treat EV-D68 infection. Like other enteroviruses, EV-D68 uses autophagic membranes for RNA replication and non-lytic release. While autophagy is often proviral for EV-D68 and other enteroviruses, our recent finding that the cellular process can also be antiviral by degrading the autophagic membranes before the virus subverts them suggests that manipulating autophagy could constitute a plausible antiviral strategy. We found that through a phenomenon called Nuclear Evacuation of Autophagic Regulators (NEAR), transcription factor EB, the master transcriptional regulator of autophagy and lysosomal biogenesis, controls antiviral autophagy. Despite regulating antiviral autophagy, TFEB is also essential for EV-D68 infection, since TFEB knockdown reduces EV-D68 titers. Interestingly, the viral 3C protease cleaves TFEB late during infection. These findings suggest that TFEB acts as a double-edged sword during EV-D68 infection. Here, we propose three aims to mechanistically characterize how TFEB regulates proviral and antiviral autophagy during EV-D68 infection and identify the specific TFEB target proteins that mediate these processes. We hypothesize that the TFEB target proteins mediating antiviral autophagy will be distinct from those orchestrating proviral autophagy. The objective of this proposal is to conduct experiments that will not only enhance our understanding of viral manipulation of autophagy but also provide new insights into the regulation of autophagy at the molecular level. With solid mentorship, collaboration, and institutional support, the experiments outlined in this proposal will help develop the necessary skills to transition into a successful independent investigator.