The broad, long-term goal of our research program is to advance knowledge of virus-host cell interactions by characterizing cellular cofactors essential for viral infections, particularly positive-strand RNA viruses such as hepatitis C virus (HCV) and dengue virus (DENV). These viruses infect millions of people worldwide and pose major threats to human health. Understanding how these viruses interact with the host cell is of critical importance to the development of diagnostics, antiviral drugs, and a prophylactic vaccine. In preliminary studies, we have uncovered a critical role of lipid droplets and one of its associated proteins in DENV and HCV entry into host cells at the membrane fusion step. Although a role of the lipid droplets in viral assembly has been reported, a function of these organelles in viral entry and membrane fusion has not been proposed before. In this study, we will investigate the mechanism of action for lipid droplets and its associated protein, CIDEB, to facilitate the entry of diverse RNA viruses. The following specific aims are proposed: (1) to define the roles of lipid droplets and their recruitment of early endosomes in virus entry. Our working hypothesis of this aim is that LDs and the recruitment of virus-containing early endosomes to LDs are required for completing viral entry. We will use pharmacological and genetic manipulations to reduce LDs in the target cells of DENV and HCV and then determine if infection by these viruses is inhibited at specific steps such as endocytosis, membrane fusion, or capsid release. (2) to determine the function of CIDEB during the infection cycle of positive-strand RNA viruses. We have demonstrated the CIDEB knockdown (KD) with RNAi reduced DENV/HCV infection and hypothesize that CIDEB can serve as a new host target for treating infections by positive-stranded RNA viruses. We will use CIDEB knockout (KO) models, generated using TAL effector nuclease (TALEN) technology, to determine the importance of CIDEB in the life cycles of various RNA viruses. The results of the proposed studies will not only provide significant insights into the virus- and host-related functions of lipid droplets and CIDEB but also may reveal new therapeutic targets for antiviral intervention directed at medically important RNA viruses.

Public Health Relevance

Positive-strand RNA viruses are a major group of human pathogens including Dengue virus and hepatitis C virus (HCV). These viruses infect millions of people worldwide and represent a significant threat to human health. No prophylactic vaccine exists for these viruses, and both the current treatment and the drugs in the development pipeline face serious drug-resistance issues. The proposed research is based on our exciting finding that a novel cellular structure and its associated protein are critical for the entry of thse RNA viruses and will both fundamentally advance our understanding of virus-host interactions and reveal new drug targets for anti-viral therapy.

Agency
National Institute of Health (NIH)
Institute
National Institute of Allergy and Infectious Diseases (NIAID)
Type
Exploratory/Developmental Grants (R21)
Project #
1R21AI111250-01
Application #
8679468
Study Section
Virology - A Study Section (VIRA)
Program Officer
Cassetti, Cristina
Project Start
2014-04-01
Project End
2016-03-31
Budget Start
2014-04-01
Budget End
2015-03-31
Support Year
1
Fiscal Year
2014
Total Cost
$220,270
Indirect Cost
$70,270
Name
Florida State University
Department
Biology
Type
Schools of Arts and Sciences
DUNS #
790877419
City
Tallahassee
State
FL
Country
United States
Zip Code
32306