Gene editing could provide a cure for HIV
While antiretroviral drugs do a goodjob of keeping HIV infections under control, scientists are workinghard to come up with a full cure for the condition. A team of researchers from theLewis Katz School of Medicine at Temple University is making real progress in that regard, successfullytesting a gene editing system, demonstrating its ability to eliminate the virus from DNA in human cells grown in culture.
Since it was first discovered in the1980s, HIV and AIDS has caused in excess of 25 million deaths.Antiretroviral drugs are effective at controlling the infection, butif patients stop having the treatment, the infection quickly takeshold and health deteriorates rapidly.
Finding a cure is problematic, as it'sdifficult to eradicate the virus once it's integrated into CD4+T-cells – the primary cells infected by HIV. Some recent attemptsto find a cure have focused on actually reactivating the virus toprompt a strong immune response to kill it, but no study has yet yieldedpositive results.
The Temple University team's approachis more subtle, using CRISPR/Cas9 gene editing technology to target andremove the virus from DNA. The tech is made up of a guide RNA, which is usedto locates the HIV-1 virus in the DNA, and a nuclease, which is thenable to edit it out of the sequence. Once the virus is eliminated,the cell's own mechanisms step in and tie up the loose ends of thegenome.
Working with T-cells from patientsinfected with HIV-1, grown in culture, the researchers were able todemonstrate the technology removing the virus, and continuing toprotect against further infection following the treatment.
The researchers also looked at whetherthe treatment had any off-target effects, or caused any toxicity –an essential investigation should the technology ever be widely used.Analyzing cells following the treatment, the team used ultra-deepwhole-genome sequencing to determine that no off-target effects hadoccurred, including any potential changes to the gene expression ofthe cell. Observations of the cells showed them to be growing andfunctioning in a healthy manner.
The results provide the most completeset of data on the pioneering new treatment, and while widespread useis still a long way off, the researchers can now move ahead with thetechnology, working towards a full cure for HIV.
Full details of the study werepublished online in the journal Scientific Reports.
Source: Temple University