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Department of Medicine

Department of Medicine

   Division of Infectious Diseases

Research


Ambrose Laboratory


Ambrose Laboratory

The Ambrose laboratory takes three approaches to studying HIV infection and therapeutics. Half of the laboratory focuses on basic molecular and cellular retrovirology, while the other half uses animal models to address important questions about HIV infection and pathogenesis.

Transmission and prevention of drug-resistant HIV
Daily oral pre-exposure prophylaxis (PrEP) using two antiretroviral drugs is effective at preventing HIV transmission in high-risk populations. A concern in using antiretroviral drugs for both treatment of HIV-infected individuals and for PrEP for uninfected individuals is the potential for transmission of or development of drug-resistant HIV isolates during PrEP. The Ambrose laboratory is studying the efficacy of long-acting PrEP in preventing transmission of HIV, including against drug-resistant isolates. In addition, we are interested in whether long-acting PrEP can lead to development of drug-resistant mutations, using state of the art single-genome sequencing methods. In turn, if resistant HIV develops or is transmitted, we are interested in understanding how this impacts subsequent antiretroviral therapy (ART). We are currently evaluating long-acting non-nucleoside reverse transcriptase inhibitors as PrEP.


Diagram of our NIH-funded study design.


Relevant publications related to this work:

Establishment and persistence of HIV/SIV in tissues
The Ambrose laboratory studies diversity of HIV or SIV that develops in the blood and in different tissues before, during, and after antiretroviral therapy to identify the nature and dynamic properties of persistent viral reservoirs at different anatomical sites. Viral evolution can be measured over time in the blood and tissues using single-genome sequencing. We have shown that viral evolution and compartmentalization is unique in mucosal tissues, such as the gastrointestinal and female genital tracts that are sites of mucosal transmission, compared to the blood or lymphoid tissues. For example, the composition of the viral DNA population in the blood and lymph nodes is mostly wild type (WT) over time. However, the viral DNA population in the gastrointestinal tract becomes dominated by mutant viruses, suggesting higher turnover of infected cells in the gut compared to the blood.




More recently we have started looking at the influence of Mycobacterium tuberculosis infection and immunity on SIV replication during co-infection, focusing on the blood and lung and using MiSeq deep sequencing. This is in collaboration with Drs. Ling Lin and Pleuni Pennings.
Relevant publications related to this work:

HIV treatment and drug resistance, including identification of new therapeutic targets
We are investigating the early post-entry events in HIV infection of different cell types. Specifically we are studying HIV capsid uncoating, reverse transcription, and nuclear entry by molecular and cellular biology, including innovative imaging techniques. Understanding these cellular pathways and the host-pathogen interactions associated with them will help us to understand HIV infection better and may provide potential novel therapeutic targets for virus inhibition. Previously we identified a capsid mutation, N74D, that disrupts HIV interaction with the host protein CPSF6 and uses a different nuclear import pathway for viral DNA. CPSF6 binds to the karyopherin-b protein TNPO3 for nuclear import through the nuclear pore complex, which contains two proteins, Nup358 and Nup153, required for HIV infection. We continue to study the processes of HIV capsid uncoating and its influence on reverse transcription, trafficking and entry into the nucleus, and use of host cell factors.


HIV integrase (IN) colocalizes with host proteins TNPO3, CPSF6, and Nup153 and moves toward the nucleus. (A) A structured illumination micrographs of tagRFP-IN at the nuclear membrane of a HeLa cell stained with antibodies against Nup153. (B) Examples of tagRFP-IN colocalized with CPSF6-iRFP670 and GFP-TNPO3 (white arrows) as they traffic together towards the nucleus during live-cell imaging of HIV-infected HeLa cells.

Relevant publications related to this work: