Combinations of long acting antiretroviral and gene-editing therapies have effectively eliminated HIV-1 in experimental animals, with the former providing long-lasting viral suppression and the latter targeting both HIV-1, the virus that causes AIDS, and CCR5, the co-receptor that helps the virus get into cells. The new research from UNMC and the Lewis Katz School of Medicine at Temple University, which published online Monday, May 1, in the journal PNAS, is the first to use these unique combinatorial therapies to cure live, humanized HIV-infected mice of viral infection.
“We merge successes in antiretroviral drug and genetic therapies created at UNMC and Temple, respectively,” said Howard Gendelman, MD, head of the Carol J. Swarts Laboratory for Emerging Neuroscience, Margaret R. Larson Professor of Internal Medicine and Chair of the Department of Pharmacology and Experimental Neuroscience (PEN) at UNMC.
“The excision of HIV-1 DNA and the inactivation of CCR5 was brought together using gene-editing technologies built on observations from reported cures in human HIV patients,” said 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. “In the few instances of HIV cures in humans, the patients underwent bone marrow transplantation for leukemia, and the donor cells that were used carried inactivating CCR5 mutations.”
Drs. Gendelman and Khalili were senior investigators on the new study. The two researchers have been longtime collaborators and have strategically combined their research strengths to find a cure for HIV in humanized mice.
“We are true partners, and what we achieved here is really spectacular,” Dr. Gendelman said. “Dr. Khalili’s team generated the essential gene-editing constructs, and we then applied those constructs in our long-acting slow effective release antiretroviral therapy (LASER ART) treated humanized mice, figuring out when to administer gene-editing therapy and carrying out analyses to maximize HIV-1 excision, CCR5 inactivation, and suppression of viral growth was at UNMC.”
The UNMC team included Prasanta Dash, PhD, an expert in molecular virology, who led the humanized mouse studies. His precision work done in collaboration with Drs. Gendelman and Santhi Gorantla, PhD, an authority on mouse model use and development was a pivotal collaboration. The LASER ART strategies were developed by Benson Edagwa, PhD, an expert medicinal and polymer chemist. Drs. Edagwa, Gendelman and their teams collaborated in producing the antiretroviral products and used them successfully in the study. Drs. Dash and Gendelman determined when to administer gene-editing therapy and developed the means to maximize HIV-1 excision, CCR5 inactivation and viral growth suppression.
In previous work, Drs. Gendelman and Khalili and their respective teams showed that HIV can be edited out from the genomes of live, humanized HIV-infected mice, leading to a cure in some animals. For that research, Dr. Khalili and co-investigator Rafal Kaminski, PhD, assistant professor at the Center for Neurovirology and Gene Editing at Temple, whose expertise in CRISPR gene-editing technology for targeting HIV-1 joined Dr. Dash as yet another successful collaboration between institutions.
While HIV cannot be eliminated by LASER ART in infected mice, the researchers found that maximal suppression of virus for time periods measured in months could facilitate antiretroviral drug penetrance into reservoirs of viral growth. This served to safely maximize viral suppression and control secondary complications of disease. Nonetheless, stoppage of treatment would cause the eventual re-emergence from tissue reservoirs and cause new cycles of rebound infection. HIV integrates its DNA into the genome of host cells and can lie dormant in tissue reservoirs for long periods of time and despite the use of antiretroviral drugs. As a consequence, when ART is stopped even after limited therapeutic times, HIV replication renews.
To prevent rebound infection, Dr. Khalili and his colleagues began work on next-generation CRISPR technology for HIV excision, developing a new, dual system aimed at permanently eliminating HIV from the Nebraska animal model.
The new dual CRISPR gene-editing strategy holds exceptional promise for treating HIV in humans. “It is a simple and relatively inexpensive approach,” Dr. Khalili noted. “The type of bone marrow transplant that has brought about cures in humans is reserved for patients who also have leukemia. It requires multiple rounds of radiation and is not applicable in resource-limited regions, where HIV infection tends to be most common.”
Experiments in humanized LASER ART-treated mice were carried out by Dr. Gendelman’s team, showing that the constructs developed at Temple, when administered together, resulted in viral suppression, restoration of human T-cells and elimination of replicating HIV-1 in 58 percent of infected animals. The findings support the idea that CCR5 has a key role in facilitating HIV infection.
The Temple team also anticipates soon testing the dual gene-editing strategy in non-human primates. To do so, Dr. Khalili will collaborate with Tricia Burdo, PhD, professor and vice chair in the Temple Department of Microbiology, Immunology and Inflammation, an expert in the use of non-human primate models for studying HIV-1, who was also a co-author on the new study. Dr. Burdo and her team are interested in understanding the involvement of CCR5 in SIV-infected primates. Her laboratory previously played a key part in research demonstrating the effectiveness and safety of CRISPR-based technology in removing HIV DNA from primate cells.
The new dual CRISPR gene-editing strategy holds exceptional promise for treating HIV in humans. “It is a simple and relatively inexpensive,” Dr. Khalili said.
“Curing HIV is the big picture,” Dr. Gendelman said. “Through our collaboration, Temple and UNMC have carried out meaningful research that could ultimately impact the lives of many.”
“We’re proud of the research being done at UNMC by Dr. Gendelman and his colleagues,” said UNMC Chancellor Jeffrey P. Gold, MD. “We look forward to further progress in this important work.”
“There are a few different kinds of approaches being discussed and, in some cases, devised to reach a functional cure for HIV,” said Robert Gallo, MD, noted pioneer in AIDS and HIV research. “This means no further therapy needed. One such approach is the utilization of the CRISPR technology to destroy the HIV provirus or even a cellular component like the possibly unneeded cell co-receptor for HIV entry. Howard Gendelman, Kamel Khalili and their colleagues at UNMC and Temple University are deeply into this technology and begin reporting on their awaited progress in this direction. They have made substantial advances as shown in this report and following their work will be of great interest to the field.”
In addition to Dr. Dash, study co-authors included Hang Su, PhD; Brady Sillman, PhD; Chen Zhang; Sruthi Sravanam, PhD; Emiko Waight, Lili Guo, PhD; Saumi Mathews, PhD; R. Lee Mosley, PhD; and Larisa Poluektova, PhD, UNMC Department of Pharmacology and Experimental Neuroscience; and Chen Chen, Pietro Mancuso, PhD; Shuren Liao, PhD; Hong Liu, PhD; Rahsan Sariyer, Maurizio Caocci and Shohreh Amini, PhD, Department of Microbiology, Immunology and Inflammation, Center for Neurovirology and Gene Editing, Lewis Katz School of Medicine at Temple University.
Congrats to both teams – this is teamwork at its finest!
Congrats to Drs. Dash, Gendelman and other members in both teams!
congrats Prasanta and Dr. Gendelman!
Congratulations and thank you so much for the hard work you guys are doing.