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In JoVE (1)
Other Publications (5)
Articles by Soohwan Oh in JoVE
JoVE Immunology and Infection
Measurement of γHV68 Infection in Mice
Department of Molecular Microbiology and Immunology, University of Southern California, Los Angeles
γ-Herpesviruses (γ-HVs) establish life-long persistency in their host. Infection of mice with γ-HV68 provides a genetically tractable in vivo model for the characterization of the lifecycle/pathogenesis of γHVs. This protocol describes the detection and quantitation of γHV68 infection at acute and latent stages following infection by plaque-forming, infectious center, and qPCR assays.
Other articles by Soohwan Oh on PubMed
The Presence of CD8+ Invariant NKT Cells in Mice
Invariant natural killer T (iNKT) cells develop in the thymus upon recognition of CD1d expressed on developing thymocytes. Although CD4 and CD8 coreceptors are not directly involved in the interaction between CD1d and the T cell receptors (TCRs) of iNKT cells, a conspicuous lack of CD8(+) iNKT cells in mice raised the question of whether CD8(+) iNKT cells are excluded due to negative selection during their thymic development, or if there is no lineage commitment for the development of murine CD8(+) iNKT cells. To address this question, we analyzed iNKT cell-specific TCR V alpha 14(+) transgenic mice, where the V alpha 14 transgene forces the generation of iNKT cells. This allows detailed study of the iNKT cell repertoire. We were able to identify CD8(+) iNKT cells which respond to the NKT cell-specific glycolipid ligand alpha-galactosylceramide. Unlike conventional iNKT cells, CD8(+) iNKT cells produce predominantly IFN-gamma but not IL-4 upon antigen stimulation. We also confirmed the presence of CD8(+) iNKT cells in wild type mice. Our results suggest that CD8(+) NKT cells do exist in mice, although their population size is quite small. Their Th1-skewed phenotype might explain why the population size of this subtype needs to be controlled tightly.
Viral Bcl-2-mediated Evasion of Autophagy Aids Chronic Infection of Gammaherpesvirus 68
Gamma-herpesviruses (gammaHVs) have developed an interaction with their hosts wherein they establish a life-long persistent infection and are associated with the onset of various malignancies. One critical virulence factor involved in the persistency of murine gamma-herpesvirus 68 (gammaHV68) is the viral homolog of the Bcl-2 protein (vBcl-2), which has been implicated to counteract both host apoptotic responses and autophagy pathway. However, the relative significance of the two activities of vBcl-2 in viral persistent infection has yet to be elucidated. Here, by characterizing a series of loss-of-function mutants of vBcl-2, we have distinguished the vBcl-2-mediated antagonism of autophagy from the vBcl-2-mediated inhibition of apoptosis in vitro and in vivo. A mutant gammaHV68 virus lacking the anti-autophagic activity of vBcl-2 demonstrates an impaired ability to maintain chronic infections in mice, whereas a mutant virus lacking the anti-apoptotic activity of vBcl-2 establishes chronic infections as efficiently as the wild-type virus but displays a compromised ability for ex vivo reactivation. Thus, the vBcl-2-mediated antagonism of host autophagy constitutes a novel mechanism by which gammaHVs confer persistent infections, further underscoring the importance of autophagy as a critical host determinant in the in vivo latency of gamma-herpesviruses.
Autophagy Evasion in Herpesviral Latency
Autophagy constitutes a major catabolic process for the quality control of internal proteins and organelles of eukaryotic cells, and is emerging as an essential part of the host antiviral defense. Many studies have shed light on the importance of autophagy in homeostasis, but it is not well understood how viruses co-opt the cellular autophagic pathway to establish virulence in vivo. Our recent study presents direct in vivo evidence for the key role of the anti-autophagic aspect of the virally encoded Bcl-2 proteins in the chronic infection of oncogenic gamma-herpesviruses and proposes that cellular autophagy may have a substantial effect on viral persistence and may influence the in vivo fitness of viruses. This discovery expands upon known antiviral activities of the autophagy machinery and also suggests new approaches for treating some virally induced diseases.
Anti-autophagic Bcl-2: Not Just an Innocent Bystander
Bcl-2, originally identified as a universal inhibitor of apoptotic cell death, has since been implicated in suppressing autophagy, the cell's quality control mechanism. Our recent study demonstrates that the anti-autophagic aspect of Bcl-2 can function as a promoter of oncogenic growth, independently of its role in apoptosis signaling. It is likely that the increase in Bcl-2 often seen in breast and other cancers might render cells error-prone by blunting autophagy, while concomitantly keeping damaged cells alive. The outcome of such a 'double hit' of Bcl-2 may synergistically promote tumor growth and increase the chance of cancer development and drug resistance.
TPL2/COT/MAP3K8 (TPL2) Activation Promotes Androgen Depletion-independent (ADI) Prostate Cancer Growth
Despite its initial positive response to hormone ablation therapy, prostate cancers invariably recur in more aggressive, treatment resistant forms. The lack of our understanding of underlying genetic alterations for the transition from androgen-dependent (AD) to ADI prostate cancer growth hampers our ability to develop target-driven therapeutic strategies for the efficient treatment of ADI prostate cancer.
