Research Topics

Host-Pathogen Interactions, Imaging, Virology

Disease Research Interests

Infectious Diseases

B.S. (Bacteriology; Genetics) University of Wisconsin-Madison
Ph.D. (Biochemistry) University of Utah
Post-Doctoral (Oncology) University of Utah
Post-Doctoral (Biology and Biological Engineering) Caltech

Mechanisms of HIV pathogenesis in animal models and human patient samples; development and application of multiscale tissue imaging methods

HIV, the causative agent of AIDS, was discovered over 35 years ago and remains a global health concern with an estimated 37 million individuals currently infected worldwide. Despite extensive efforts, there is currently no cure for HIV and although antiretroviral therapy allows individuals with access to medicine to lead normal lives, the presence of a reservoir of latently infected cells that rebound upon cessation of treatment requires infected individuals to remain on treatment indefinitely. My lab focuses on using advanced imaging techniques to visualize HIV pathogenesis in tissues with the goals of understanding relevant modes of virus dissemination, investigating the latent virus reservoir, and characterizing the effectiveness of anti-HIV therapies.

Relatively little is known about the mechanisms of HIV dissemination and the organization of the latent reservoir of HIV infected cells in human patients at the resolution of individual infected cells and virions within intact tissues. In order to address these limitations, my lab is utilizing a multiscale imaging approach to visualize mechanisms of HIV pathogenesis in tissues from small animal models of HIV infection at multiple levels of volume and resolution.

Mice with humanized immune systems are a tractable model for studying HIV infection in the presence of an immune response and recapitulate many aspects of disease in humans. In this model, human immune cells are introduced into immunodeficient mice and a “human-like” immune system is rapidly reconstituted within weeks to months. These “humanized” mice can be infected with HIV and be monitored longitudinally in order to understand the interactions between the virus and the immune system during specific stages of infection. For example, bioluminescence imaging allows whole animal imaging and can identify regions of active HIV replication within a living animal for further analysis with higher resolution methods.

For larger volume imaging with single-cell resolution we use tissue clearing and light microscopy. Tissue clearing involves treating tissues with chemical cocktails that remove opaque biomolecules that limit light penetration into the sample. These cleared tissues become optically transparent and can be labeled with fluorescent probes specific for actively infected cells, latently infected cells, and individual immune cell populations. Light microscopy of labeled tissues reveals the spatial distribution of individual HIV-infected cells and target cells within volumes (mm3-cm3) of intact tissue containing tens of thousands to millions of cells. For smaller volume imaging with single-virus resolution we use electron microscopy which generates higher resolution 3D information to reveal ultrastructural details of HIV-infected cells and individual viruses within tissues.

Combining these multiscale imaging techniques provides insights into mechanisms of HIV pathogenesis in tissues at previously unattainable levels of volume and resolution, reveals differences between mechanisms of infection in tissues compared to cultured cells, and can identify virus reservoirs or tissue sanctuaries at specific times during HIV infection. Importantly, this multiscale imaging approach is directly translatable to non-human primates and human patient samples that we are pursuing through established collaborations.

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