Mothes, W. | Search bioRxiv

bioRxiv2019

Longitudinal bioluminescent imaging of HIV-1 infection during antiretroviral therapy and treatment interruption in humanized mice

Non-invasive bioluminescent imaging (NIBLI) of HIV-1 infection dynamics allows for real-time monitoring of viral spread and the localization of infected cell populations in living animals. In this report, we describe full-length replication-competent GFP and Nanoluciferase (Nluc) expressing HIV-1 reporter viruses from two clinical transmitted / founder (T/F) stains: TRJO.c and Q23.BG505. By infecting humanized mice with these HIV-1 T/F reporter viruses, we were able to directly monitor longitudinal viral spread at whole-animal resolution via NIBLI at a sensitivity of as few as 30-50 infected cells. Bioluminescent signal strongly correlated with HIV-1 infection and responded proportionally to virus suppression in vivo in animals treated daily with a combination antiretroviral therapy (cART) regimen. Longitudinal NIBLI following cART withdrawal visualized tissue-sites that harbored virus during infection recrudescence. Notably, we observed rebounding infection in the same lymphoid tissues where infection was first observed prior to ART treatment. Our work demonstrates the utility of our system for studying in vivo viral infection dynamics and identifying infected tissue regions for subsequent analyses.\n\nAuthor SummaryNon-invasive bioluminescent imaging (NIBLI) in small animals allows for in vivo longitudinal imaging of infection spread and pathogenesis. We have taken advantage of the small luciferase reporter protein, Nanoluciferase (Nluc), to generate a replication-competent HIV-1 reporter virus to allow for NIBLI of viral infection in humanize mice. NIBLI via Nluc enabled us to directly visualize longitudinal spreading patterns before, during, and after interruption of daily doses of combined antiretroviral therapy (cART). We observed that rebounding infection often emerged in tissue regions originally associated with infected cells prior to cART treatment. Thus, Nluc-based NIBLI of HIV-1 infection can be used as an experimental tool to study early events involved in viral dissemination and spread from initial sites of infection to draining lymphoid tissues as well as locate infected tissues for subsequent cellular characterization of HIV-1 infected cells.

microbiology↗

bioRxiv2018

SV40 polyomavirus activates the Ras-MAPK signaling pathway for vacuolization, cell death, and virus release

Polyomaviruses are a family of small, non-enveloped DNA viruses that can cause severe disease in immunosuppressed individuals. Studies with SV40, a well-studied model polyomavirus, have revealed the role of host proteins in polyomavirus entry and trafficking to the nucleus, viral transcription and DNA replication, and cell transformation. In contrast, little is known about host factors or cellular signaling pathways involved in the late steps of productive infection leading to polyomavirus release. We previously showed that cytoplasmic vacuolization, a characteristic late cytopathic effect of SV40, depends on the specific interaction between the major viral capsid protein VP1 and its cell surface ganglioside receptor GM1. Here we show that late during infection, SV40 activates a signaling cascade in permissive CV-1 monkey cells involving Ras, Rac1, MKK4 and JNK to induce SV40-specific cytoplasmic vacuolization and subsequent cell lysis and virus release. Inhibition of individual components of this signaling pathway inhibits vacuolization, lysis and virus release, even though high-level intracellular virus replication occurs. The identification of this pathway for SV40-induced vacuolization and virus release provides new insights into the late steps of non-enveloped virus infection and reveals potential drug targets for the treatment of diseases caused by these viruses.\n\nIMPORTANCEThe polyomaviruses are small DNA viruses that include important model viruses and human pathogens that can cause fatal disease, including cancer, in immunosuppressed individuals. There are no vaccines or specific antiviral agents for any polyomavirus. Here, we show that late during infection, SV40 activates a signaling cascade involving Ras, Rac, and JNK that is required for cytoplasmic vacuolization and efficient virus release. This pathway may represent a new point of intervention to control infection by these viruses.

microbiology↗