Gene Editing for HIV Therapies

Innovative novel therapy making news is always exciting, and brings with it, hope. Because while there have been great advancements in the realm of HIV treatment, but eradicating it proves to be a challenge today. HIV integrates with host T cells, white blood cells causing lifelong infection. Newer and better drugs are being introduced ever so often, and Highly Active Antiretroviral Therapy (HAART) has successfully controlled the amount of newly formed virus, preventing new cells from being infected, and effectively lowering the viral load. This has slowed down the spread of the virus, and brought about a tremendous improvement in the well-being of persons living with HIV (PLHIV). PLHIVs are living better, longer, more fulfilled lives than before.

HAART has served the community well for the last 2 decades and will continue to do so for many more to come. Yet, many people I speak to, often pray and hope for a cure, or that they do not have to rely on a daily dose of medication, that allows people like myself to continue to live our lives, our life now is largely dependent on the drugs. It’s restrictive, it serves as a daily reminder for some, and for many, an added burden on our already limited monthly income. HIV drugs, though much more affordable and accessible now, still is expensive in this part of the world. The fear of treatment failures continues to plague many too, despite many reassurance from the pharmaceutical and scientific community.

Which brings us to gene editing. With the introduction of a revolutionary tool known as CRISPR (pronoused as crisper) for editing genes, and in this case, it targets the removal of some parts (CCR5) of our T-cell and prevents the virus from attaching itself onto the cell in the first place. This helps the cell protects itself against an HIV infection. According to studies, in patients infected with HIV, mutations resulting in resistance to antiretroviral therapy (ART) was a major cause of treatment failure. It might be possible to assess these resistance mutations by using genotyping tests that could probe specific mutations in the HIV genome or in the sequencing of specific genes and edit those genes accordingly.

The main hurdle toward eradicating HIV is that it integrates into long-lived immune cells, such as memory helper T cells, which don’t actively express all HIV genes, with the HIV genome remaining relatively latent inside the cell. According to Robert Kruse of Biotechr,

An elegant solution to all these problems would be to simply cut the HIV genome out of the host cell, whereafter it forms episomal DNA that is lost with cell division. With the rise of CRISPR, one solution has been to use Cas9 to cut HIV out of the genome, as demonstrated here and here. A similar strategy has used TALENs to edit HIV from the genome. Just a couple weeks ago, a paper was published online showed in vivo administration of an AAV expressing Cas9 and gRNA could remove HIV sequences in a transgenic HIV mouse model where the target was in every chromosome, in a fraction of the lymphocytes and cells of other organs. However, the strategy has a number of limitations.

Click here to read more about research into novel HIV therapies

While we are still along way before persons living with HIV/AIDS can truly benefit from novel therapies such as gene editing, we are getting better at it with each day. Who knows what this may lead too, and new treatments are just on the horizon.

Avin is a person living with HIV and the webmaster of this awesome site and has been working with AFA to raise the awareness of living with HIV/AIDS in Singapore and assisting other persons living with HIV. Following Mr. Paddy Chew, he is only the second Singaporean living with HIV who has come out publicly.