KSHV is etiologically associated with chronic inflammation associated Kaposi's sarcoma (KS) and primary effusion B-cell lymphoma (PEL) in oral and other body sites that occur in HIV-1 infected patients. The inflammatory response is one of the key elements of KSHV pathogenesis. KS lesions are characterized by inflammatory cells and cytokines. The KS lesion endothelial cells and B-cell lines from PEL carry multiple copies of the KSHV genome in a latent state. Our long term goals are to elucidate KSHV's interactions with the host innate response during primary infection and latency, the pathways of cytokine induction and to define their role in KSHV pathogenesis. Our rationale is that such detailed knowledge is crucial for designing therapeutic strategies to control KSHV infection, inflammation and the associated malignancies. KSHV infected cells secrete multi-functional IL-1 and IL-18 cytokines into the supernatants. IL-1 and IL-18 are synthesized as inactive proIL-1 and proIL-18 and then undergo processing by activated caspase-1. However, caspase-1 itself is synthesized as a procaspase-1 and undergoes activation leading into an auto- proteolytic cleavage. Procaspase-1 activation is mediated by a molecular platform called an inflammasome that is formed by homotypic interactions of a sensor protein recognizing the danger trigger, an adaptor ASC molecule, and procaspase-1. Our studies have demonstrated that the pathogen sensing functions of the inflammasome also extends into the nucleus. During de novo KSHV infection of human microvascular dermal endothelial (HMVEC-d) cells, gamma-interferon-inducible protein (IFI16) is colocalized with the KSHV genome in the infected endothelial cell nucleus, and interacted with ASC and procaspase-1 to form an inflammasome complex. IFI16 also colocalized with the KSHV genome in the nuclei of latently infected endothelial and PEL cells, and only the IFI16 dependent inflammasome is constitutively activated in KSHV latently infected cells. Human KS and PEL lesions showed evidence of IFI16-ASC inflammasome activation. Constitutive induction of the IFI16-inflammasome was also observed in ?1-EBV latency I, II and III cells. Together with the ability of KSHV and EBV latency in the presence of the IFI16-inflammasome and association of IFI16 with KSHV and EBV genome in the latently infected cells, we hypothesize that IFI16 is involved in the innate sensing of foreign episomal DNA in the nucleus and KSHV utilizes IFI16 for its latency. This hypothesis will be tested by three innovative and interlinked specific aims. These studies are significant since such elucidation wil lead into designing therapeutic strategies to control KSHV induced inflammation and the associated malignancies. These will also profoundly enhance the current concepts of innate sensing in the nucleus and will lead into new technologies and treatments that will benefit not only the KSHV area of research but also other fields.

Public Health Relevance

Kaposi's sarcoma associated herpesvirus (KSHV) is etiologically associated with Kaposi's sarcoma and primary effusion lymphoma. The proposed studies will investigate innate sensing of the KSHV genome in the infected cell nucleus. These studies are significant since such comprehensive understanding of nuclear innate responses will provide novel targets to block latent KSHV infection and the associated diseases.

Agency
National Institute of Health (NIH)
Institute
National Cancer Institute (NCI)
Type
Research Project (R01)
Project #
5R01CA180758-03
Application #
8997479
Study Section
AIDS-associated Opportunistic Infections and Cancer Study Section (AOIC)
Program Officer
Read-Connole, Elizabeth Lee
Project Start
2014-02-07
Project End
2019-01-31
Budget Start
2016-02-01
Budget End
2017-01-31
Support Year
3
Fiscal Year
2016
Total Cost
Indirect Cost
Name
Rosalind Franklin University
Department
Microbiology/Immun/Virology
Type
Schools of Medicine
DUNS #
069501252
City
North Chicago
State
IL
Country
United States
Zip Code
60064
Kumar, Binod; Roy, Arunava; Veettil, Mohanan Valiya et al. (2018) Insight into the Roles of E3 Ubiquitin Ligase c-Cbl, ESCRT Machinery, and Host Cell Signaling in Kaposi's Sarcoma-Associated Herpesvirus Entry and Trafficking. J Virol 92:
Iqbal, Jawed; Ansari, Mairaj Ahmed; Kumar, Binod et al. (2016) Histone H2B-IFI16 Recognition of Nuclear Herpesviral Genome Induces Cytoplasmic Interferon-? Responses. PLoS Pathog 12:e1005967
Roy, Arunava; Dutta, Dipanjan; Iqbal, Jawed et al. (2016) Nuclear Innate Immune DNA Sensor IFI16 Is Degraded during Lytic Reactivation of Kaposi's Sarcoma-Associated Herpesvirus (KSHV): Role of IFI16 in Maintenance of KSHV Latency. J Virol 90:8822-41
Ansari, Mairaj Ahmed; Dutta, Sujoy; Veettil, Mohanan Valiya et al. (2015) Herpesvirus Genome Recognition Induced Acetylation of Nuclear IFI16 Is Essential for Its Cytoplasmic Translocation, Inflammasome and IFN-? Responses. PLoS Pathog 11:e1005019
Dutta, Dipanjan; Dutta, Sujoy; Veettil, Mohanan Valiya et al. (2015) BRCA1 Regulates IFI16 Mediated Nuclear Innate Sensing of Herpes Viral DNA and Subsequent Induction of the Innate Inflammasome and Interferon-? Responses. PLoS Pathog 11:e1005030
Johnson, Karen E; Bottero, Virginie; Flaherty, Stephanie et al. (2014) IFI16 restricts HSV-1 replication by accumulating on the hsv-1 genome, repressing HSV-1 gene expression, and directly or indirectly modulating histone modifications. PLoS Pathog 10:e1004503
Singh, Vivek Vikram; Dutta, Dipanjan; Ansari, Mairaj Ahmed et al. (2014) Kaposi's sarcoma-associated herpesvirus induces the ATM and H2AX DNA damage response early during de novo infection of primary endothelial cells, which play roles in latency establishment. J Virol 88:2821-34
Ansari, Mairaj Ahmed; Singh, Vivek Vikram; Dutta, Sujoy et al. (2013) Constitutive interferon-inducible protein 16-inflammasome activation during Epstein-Barr virus latency I, II, and III in B and epithelial cells. J Virol 87:8606-23
Johnson, Karen E; Chikoti, Leela; Chandran, Bala (2013) Herpes simplex virus 1 infection induces activation and subsequent inhibition of the IFI16 and NLRP3 inflammasomes. J Virol 87:5005-18