According to recent research from the Lewis Katz School of Medicine at Temple University and the University of Nebraska Medical Center (UNMC), a gene-editing therapy that targets two entities, namely HIV-1 (the virus responsible for causing AIDS) and CCR5 (the co-receptor that facilitates virus entry into cells), can effectively eradicate HIV infection. This marks the first time that a combination of a dual gene-editing approach and antiretroviral medications has been utilized to cure animals of HIV-1, as detailed in a publication in the journal The Proceedings of the National Academy of Sciences (PNAS).
Kamel Khalili, PhD, Laura H. Carnell Professor and Chair of the Department of Microbiology, Immunology, and Inflammation, Director of the Center for Neurovirology and Gene Editing, and Director of the Comprehensive NeuroAIDS Center at the Lewis Katz School of Medicine, explained that the inspiration for combining HIV-1 DNA excision with CCR5 inactivation using gene-editing technology came from previous observations of HIV cures in human patients. In these rare cases, the patients received bone marrow transplants to treat leukemia, and the transplanted donor cells contained mutations that inactivated the CCR5 gene.
Howard E. Gendelman, MD, Professor and Chair of the Department of Pharmacology and Experiential Neuroscience at UNMC, and Dr. Khalili served as senior investigators for the recent study. These two researchers have a longstanding history of collaboration and have combined their respective research expertise to develop a cure for HIV.
Dr. Gendelman expressed his partnership with Dr. Khalili, stating that their joint efforts were critical in achieving the study's remarkable results. He further explained that Dr. Khalili's team created the fundamental gene-editing constructs, and his team utilized those constructs in their LASER-ART mouse model at UNMC. They also determined the optimal time to administer gene-editing therapy and conducted analyses to optimize HIV-1 DNA excision, CCR5 inactivation, and suppression of viral replication.
In their earlier research, Drs. Khalili and Gendelman, along with their teams, demonstrated that HIV could be eliminated from the genomes of live, humanized mice infected with the virus, resulting in a cure in certain animals. This work involved a combination of CRISPR gene-editing technology for targeting HIV-1, developed by Dr. Kaminski and Dr. Khalili, with a therapeutic strategy called long-acting slow-effective release (LASER) antiretroviral therapy (ART), which was co-developed by Dr. Gendelman and Dr. Edagwa. LASER ART maintains low levels of HIV replication for extended periods, decreasing the need for frequent ART administration.
While HIV could be eradicated in LASER-ART mice, the scientists observed that the virus may resurface from tissue reservoirs and lead to a relapse of infection. This phenomenon resembles the relapse of infection that occurs in human subjects who discontinue or undergo an interruption in ART treatment. Because HIV integrates its genetic material into the host cells' genome, it can remain dormant in tissue reservoirs for extended periods, beyond the reach of antiretroviral drugs. Consequently, the cessation of ART reactivates HIV replication, resulting in the development of AIDS.
In order to avert relapse infection, Dr. Khalili and colleagues initiated research on advanced CRISPR technology to remove HIV, devising a novel, dual system intended to eradicate the virus permanently from animal models. Their hypothesis was based on success stories of HIV patients who underwent bone marrow transplants for leukemia and were cured of HIV; they believed that the loss of CCR5, the virus's receptor, was critical to achieving permanent elimination of HIV infection. They developed a straightforward and more convenient procedure for deactivating CCR5, which entails an intravenous administration of the CRISPR gene editing molecule.
Dr. Gendelman's team conducted experiments on humanized LASER-ART mice, which demonstrated that the constructs created at Temple achieved viral suppression, rejuvenation of human T-cells, and eradication of replicating HIV-1 in 58 percent of the infected animals when administered simultaneously. These findings reinforce the concept that CCR5 plays a critical role in enabling HIV infection.
The Temple team is planning to evaluate the dual gene-editing approach in non-human primates in the near future. To accomplish this, Dr. Khalili will collaborate with Tricia H. Burdo, PhD, a Professor and Vice Chair in the Department of Microbiology, Immunology, and Inflammation at the Katz School of Medicine, who is an established expert in using non-human primate models to investigate HIV-1. Dr. Burdo was also a co-author of the recent study. Her team is interested in comprehending the involvement of CCR5 in SIV-infected primates. In prior research, her laboratory played a crucial role in demonstrating the safety and efficacy of CRISPR-based technology in eliminating HIV DNA from primate cells.
The dual CRISPR gene-editing approach represents a highly promising treatment option for HIV in humans. According to Dr. Khalili, "It is a straightforward and cost-effective method." The bone marrow transplant procedure that has resulted in HIV cures in humans is typically reserved for individuals with leukemia, and it entails multiple rounds of radiation therapy. This approach is not feasible in regions with limited resources, where HIV infections are most prevalent. (PB/Newswise)
