Multifaceted roles for STAT3 in gammaherpesvirus latency revealed through in vivo B cell knockout models
Chad H. Hogan,
Shana M. Owens,
Glennys V. Reynoso,
Yifei Liao,
Thomas J. Meyer,
Monika A. Zelazowska,
Bin Liu,
Xiaofan Li,
Anna K. Grosskopf,
Camille Khairallah,
Varvara Kirillov,
Nancy C. Reich,
Brian S. Sheridan,
Kevin M. McBride,
Benjamin E. Gewurz,
Heather D. Hickman,
J. Craig Forrest,
Laurie T. Krug
Affiliations
Chad H. Hogan
Graduate Program in Genetics, Stony Brook University, Stony Brook, New York, USA
Shana M. Owens
Department of Microbiology and Immunology, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA
Glennys V. Reynoso
Viral Immunity and Pathogenesis Unit, Laboratory of Clinical Immunology and Microbiology, National Institute of Allergy and Infectious Diseases, NIH, Bethesda, Maryland, USA
Yifei Liao
Division of Infectious Disease, Department of Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachusetts, USA
Thomas J. Meyer
CCR Collaborative Bioinformatics Resource, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, USA
Monika A. Zelazowska
Department of Epigenetics and Molecular Carcinogenesis, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA
Bin Liu
Department of Epigenetics and Molecular Carcinogenesis, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA
Xiaofan Li
HIV & AIDS Malignancy Branch, National Cancer Institute, NIH, Bethesda, Maryland, USA
Anna K. Grosskopf
HIV & AIDS Malignancy Branch, National Cancer Institute, NIH, Bethesda, Maryland, USA
Camille Khairallah
Department of Microbiology and Immunology, Renaissance School of Medicine, Stony Brook University, Stony Brook, New York, USA
Varvara Kirillov
Department of Microbiology and Immunology, Renaissance School of Medicine, Stony Brook University, Stony Brook, New York, USA
Nancy C. Reich
Department of Microbiology and Immunology, Renaissance School of Medicine, Stony Brook University, Stony Brook, New York, USA
Brian S. Sheridan
Department of Microbiology and Immunology, Renaissance School of Medicine, Stony Brook University, Stony Brook, New York, USA
Kevin M. McBride
Department of Epigenetics and Molecular Carcinogenesis, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA
Benjamin E. Gewurz
Division of Infectious Disease, Department of Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachusetts, USA
Heather D. Hickman
Viral Immunity and Pathogenesis Unit, Laboratory of Clinical Immunology and Microbiology, National Institute of Allergy and Infectious Diseases, NIH, Bethesda, Maryland, USA
J. Craig Forrest
Department of Microbiology and Immunology, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA
Laurie T. Krug
HIV & AIDS Malignancy Branch, National Cancer Institute, NIH, Bethesda, Maryland, USA
ABSTRACT Cancers associated with the oncogenic gammaherpesviruses, Epstein-Barr virus and Kaposi sarcoma herpesvirus, are notable for their constitutive activation of the transcription factor signal transducer and activator of transcription 3 (STAT3). To better understand the role of STAT3 during gammaherpesvirus latency and the B cell response to infection, we used the model pathogen murine gammaherpesvirus 68 (MHV68). Genetic deletion of STAT3 in B cells of CD19cre/+Stat3f/f mice reduced peak MHV68 latency approximately sevenfold. However, infected CD19cre/+Stat3f/f mice exhibited disordered germinal centers and heightened virus-specific CD8 T cell responses compared to wild-type (WT) littermates. To circumvent the systemic immune alterations observed in the B cell-STAT3 knockout mice and more directly evaluate intrinsic roles for STAT3, we generated mixed bone marrow chimeric mice consisting of WT and STAT3 knockout B cells. We discovered a dramatic reduction in latency in STAT3 knockout B cells compared to their WT B cell counterparts in the same lymphoid organ. RNA sequencing of sorted germinal center B cells revealed that MHV68 infection shifts the gene signature toward proliferation and away from type I and type II IFN responses. Loss of STAT3 largely reversed the virus-driven transcriptional shift without impacting the viral gene expression program. STAT3 promoted B cell processes of the germinal center, including IL-21-stimulated downregulation of surface CD23 on B cells infected with MHV68 or EBV. Together, our data provide mechanistic insights into the role of STAT3 as a latency determinant in B cells for oncogenic gammaherpesviruses.IMPORTANCEThere are no directed therapies to the latency program of the human gammaherpesviruses, Epstein-Barr virus and Kaposi sarcoma herpesvirus. Activated host factor signal transducer and activator of transcription 3 (STAT3) is a hallmark of cancers caused by these viruses. We applied the murine gammaherpesvirus pathogen system to explore STAT3 function upon primary B cell infection in the host. Since STAT3 deletion in all CD19+ B cells of infected mice led to altered B and T cell responses, we generated chimeric mice with both normal and STAT3-deleted B cells. B cells lacking STAT3 failed to support virus latency compared to normal B cells from the same infected animal. Loss of STAT3 impaired B cell proliferation and differentiation and led to a striking upregulation of interferon-stimulated genes. These findings expand our understanding of STAT3-dependent processes that are key to its function as a pro-viral latency determinant for oncogenic gammaherpesviruses in B cells and may provide novel therapeutic targets.
