Our Research

The Ambrose Lab investigates the post-entry events in HIV infection of different cell types as part of the Pittsburgh Center for HIV Protein Interactions. Specifically, we study HIV capsid uncoating, reverse transcription, and nuclear entry using molecular and cellular biology, including innovative imaging techniques. We have characterized capsid mutations (i.e. N74D, N57A, etc.) that disrupt HIV interactions with host proteins, impacting 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 in different cell types. Understanding mechanisms of HIV infection may lead to novel therapeutics to inhibit virus replication. In addition, we study HIV resistance to novel capsid, reverse transcriptase, and integrase inhibitors to understand both the mechanisms of action of these drugs as well as understand basic HIV biology. Recently we began work studying SARS-CoV-2 post-entry biology research as part of the Pittsburgh Center for Vaccine Research.

Daily oral pre-exposure prophylaxis (PrEP) using two antiretroviral drugs is effective at preventing HIV transmission in high-risk populations. The Ambrose Lab evaluates nanoparticle formulations of antiretroviral inhibitors as PrEP and HIV treatment. 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 during PrEP. The Ambrose Lab studies the efficacy of long-acting PrEP in preventing transmission of drug-resistant HIV. In addition, we evaluate whether long-acting PrEP can lead to development of drug-resistant mutations, using single-genome sequencing methods. If resistant HIV develops or is transmitted, we investigate how this impacts subsequent antiretroviral therapy (ART) and composition of viral tissue reservoirs. In a recent collaboration with the Gummuluru and Reinhard Labs, we are evaluating novel antiretroviral nanoparticle formulations for improved delivery of drugs into lymphoid and mucosal tissues where most HIV-infected cells reside.

As part of the Pittsburgh Center for Evolutionary Biology and Medicine (CEBaM), the Ambrose Lab studies diversity of HIV/SIV that develops in the blood and in tissues before, during, and after antiretroviral therapy to identify the nature and dynamic properties of persistent viral reservoirs at different anatomical sites. We showed that evolution and compartmentalization of drug-resistant viruses are 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 over time. However, the viral DNA population in the gastrointestinal (GI) tract becomes dominated by mutant viruses, suggesting higher turnover of infected cells in the GI tract compared to the blood. In a  collaboration with the Lin Lab and as part of the Pittsburgh Center for Vaccine Research (CVR), we are also investigating the influence of M. tuberculosis infection and immunity on SIV replication during co-infection, focusing on the blood and lung using MiSeq deep sequencing.