The genetic modification technique, CRISPR-Cas9 which is benefiting the DNA sequence linked to Cas9 protein, may soon be used to eradicate HIV in those who are already infected.
Today, a research group coordinated by Temple University has studied, on animal models, a combined treatment consisting of an antiretroviral therapy together with the CRISPR-Cas9 technique which is used to clean the cells affected by the DNA of the virus.
Currently, the preferred therapy against HIV infections Antiretroviral Therapy (ART) which suppresses self-replication of the virus even if it does not completely eliminate it from the body and it must be taken throughout life. If the treatment is interrupted, the infection regains strength through the replication of the virus and can lead to the development of AIDS.
This recovery is directly attributed to the virus's ability to integrate its DNA into the genome of immune system cells where it remains silent and cannot be reached by antiretrovirals.
CRISPR-Cas9 against HIV
Previously, the Temple University research group had developed a CRISPR-Cas9 based technology, with a system that carries gene therapy aiming at removing the DNA of HIV from the genome of these cells in which it lurks.
The authors have shown that in rats and mice CRISPR might be able to effectively remove large DNA fragments of HIV from infected cells, significantly modifying the composition of the virus gene. However, just like antiretroviral therapy, genetic editing has failed to completely eliminate HIV from animals.
It have been made possible thanks to pharmacological variations of the chemical structure of antiretroviral drugs. The drugs were packaged in nanocrystals (nanometer-sized crystals, millionths of a millimeter) to improve distribution in tissues that most likely contain the hidden virus. "We wanted to see if Laser-ART can suppress the replication of HIV," said co-author Kamel Khalili, who coordinated the study, "so as to allow CRISPR-Cas9 to completely clean the cells from the DNA of the virus."
To test this approach, the authors used engineered mice that produced human T lymphocytes susceptible to HIV infection. Once the virus was contracted, the animals were treated with Laser-ART and then with the CRISPR-Cas9 technique.
By combining these two strategies, the researchers were able to reach the goal. At the end of the treatment, in fact, in about a third of the infected mice, the virus had been completely eradicated. The study shows that a treatment to suppress the self-replication of HIV followed by a therapy based on genetic editing, when applied in this sequence, can eliminate HIV from the cells and organs of the infected animals.
Now we have a clear path in which to move to carry out trials in non-human primates and possibly clinical trials in patients within a year.