DNA viruses are responsible for extensive morbidity and mortality on a worldwide basis. Viral homologs of anti-apoptotic Bcl-2 family proteins are encoded in the genomes of several classes of DNA viruses. In Vaccinia Virus (VV), a poxvirus-family member that has served as a paradigm for investigations of many aspects of host-pathogen interactions, at least two viral Bcl-2 genes have been identified, F1L and N1L. Neither F1L nor N1L is required for VV infection or replication, but both of these genes make strong contributions to virulence in vivo. Thus, these viral Bcl-2 (vBcl-2) homologs are critically important for in vivo viral pathogenicity of VV. While the anti-apoptotic activity of F1L and N1L is an obvious candidate for explaining their contribution to viral virulence, we have discovered that F1L and N1L have additional functions that include binding to and suppressing the pro-inflammatory actions of NLR-family proteins, important mediators of innate immunity. Viral Bcl-2 proteins are also known to bind Beclin and suppress autophagy, recently recognized as a host defense mechanism against pathogens. We hypothesize the vBcl-2 homologs are multifunctional proteins that utilize 3 discrete mechanisms to thwart host defense mechanisms: (a) suppression of apoptosis;(b) inhibition of autophagy;and (c) interference with NLR-mediated innate immune responses. The hypothesis that we will test is that neutralization by vBcl-2 proteins of each of these 3 classes of host cell targets significantly contributes to virulence. Specifically, we will: (1) Produce site-specific mutations in F1L and N1L that selectively abolish their ability to interact with (a) pro-apoptotic Bcl-2 family proteins [apoptosis];(b) NLRs [inflammation];and (c) Beclin [autophagy];(2) Test the effects of the engineered vBcl-2 proteins on apoptosis, inflammation, and autophagy in cultured cells;(3) Produce recombinant vaccinia viruses with knock-in of F1L and N1L mutants;and (4) Compare the virulence of these recombinant vaccinia viruses in mice. By using VV as a model system, our results will lay a foundation for understanding the role of viral Bcl-2 homologs in viral pathogenicity, thus serving as a paradigm for other DNA viruses that contain vBcl-2 genes and that cause debilitating human diseases. Also, by learning how viruses interfere with apoptosis, autophagy, and inflammation, the information generated may reveal novel strategies for mimicking aspects of vBcl-2 function in therapeutically useful ways for addressing disorders in which excessive apoptosis, autophagy, and inflammation play central roles.

Public Health Relevance

DNA viruses are responsible for extensive morbidity and mortality on a worldwide basis, and yet few therapeutic options are available to counteract these pathogens. Viral homologs of anti-apoptotic Bcl-2 family proteins are encoded in the genomes of several classes of DNA viruses but their roles and mechanism in viral disease are largely unknown. The hypothesis that we will test is that neutralization by viral Bcl-2 proteins of specific classes of host cell proteins significantly contributes to virulence, which will lay a foundation for developing new strategies for viral therapeutics based on disrupting interactions of viral Bcl-2 proteins with their host cell targets.

National Institute of Health (NIH)
National Institute of Allergy and Infectious Diseases (NIAID)
Research Project (R01)
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Virology - B Study Section (VIRB)
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Challberg, Mark D
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Sanford-Burnham Medical Research Institute
La Jolla
United States
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Milutinovic, Snezana; Kashyap, Arun K; Yanagi, Teruki et al. (2016) Dual Agonist Surrobody Simultaneously Activates Death Receptors DR4 and DR5 to Induce Cancer Cell Death. Mol Cancer Ther 15:114-24
Godoi, Paulo H C; Wilkie-Grantham, Rachel P; Hishiki, Asami et al. (2016) Orphan Nuclear Receptor NR4A1 Binds a Novel Protein Interaction Site on Anti-apoptotic B Cell Lymphoma Gene 2 Family Proteins. J Biol Chem 291:14072-84
Yang, Zhifen; Wilkie-Grantham, Rachel P; Yanagi, Teruki et al. (2015) ATG4B (Autophagin-1) phosphorylation modulates autophagy. J Biol Chem 290:26549-61
D'Osualdo, Andrea; Anania, Veronica G; Yu, Kebing et al. (2015) Transcription Factor ATF4 Induces NLRP1 Inflammasome Expression during Endoplasmic Reticulum Stress. PLoS One 10:e0130635
Yanagi, Teruki; Krajewska, Maryla; Matsuzawa, Shu-ichi et al. (2014) PCTAIRE1 phosphorylates p27 and regulates mitosis in cancer cells. Cancer Res 74:5795-807
Gerlic, Motti; Faustin, Benjamin; Postigo, Antonio et al. (2013) Vaccinia virus F1L protein promotes virulence by inhibiting inflammasome activation. Proc Natl Acad Sci U S A 110:7808-13
Madiraju, Charitha; Welsh, Kate; Cuddy, Michael P et al. (2012) TR-FRET-based high-throughput screening assay for identification of UBC13 inhibitors. J Biomol Screen 17:163-76
Askari, Nadav; Correa, Ricardo G; Zhai, Dayong et al. (2012) Expression, purification, and characterization of recombinant NOD1 (NLRC1): A NLR family member. J Biotechnol 157:75-81
Gregory, Sean M; Davis, Beckley K; West, John A et al. (2011) Discovery of a viral NLR homolog that inhibits the inflammasome. Science 331:330-4
Yip, Kenneth W; Cuddy, Michael; Pinilla, Clemencia et al. (2011) A high-content screening (HCS) assay for the identification of chemical inducers of PML oncogenic domains (PODs). J Biomol Screen 16:251-8

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