In the summer of 1981, the world first became aware of the disastrous new epidemic: HIV/AIDS. Since then, the disease has spread globally, including New York, where our team is based.
Even today, HIV remains one of the leading causes of death for adults aged 25-44 in the United States, ranking 13th overall in 2022. Beyond the cases, HIV carries decades worth of stigma, misinformation, and social impact. It is not only a scientific challenge, but also a community one, making it important for all of us.
Our project was created from the experience of one of our co-team leads, Jessy, whose research lab has been working with CRISPR-Cas9. However, her team encountered challenges with Cas9, which led them to explore CRISPR-Cas13, which targeted RNA instead of DNA. Jessy wanted to expand on its potential through iGEM. Additionally, one of our other team members, Ann, noticed that research funding for HIV had significantly decreased in recent years despite it being a global health issue. Jessy recognized this gap and realized that Cas13a’s single-stranded RNA-targeting ability could be utilized to address HIV. This idea became the foundation of our project, and inspired our substudy on understanding how recent budget cuts and grant terminations have impacted the HIV research climate.
Our project centers on utilizing Cas13a, an RNA-targeting CRISPR enzyme known for its high specificity and minimal off-target cleavage. Cas13a has the ability to recognize and cleave HIV single-stranded RNA (ssRNA). In the context of HIV infections, this cleavage disrupts the virus’s ability to create further issues within the body.
To deliver Cas13a efficiently into target cells, we have developed a protein-based delivery system using a detoxified single-chain diphtheria toxin (DTA) as a translocation carrier. This enables receptor-mediated delivery of large protein cargoes, such as Cas13a, directly into cells.
To ensure targeted delivery, we have engineered a fusion protein composed of CRISPR-Cas13a, DTA, and GP120. The GP120 fragment is a ligand derived from the HIV virus itself. It binds specifically to CD4 receptors on T-helper cells, which are the primary targets of HIV infection. Once inside the cell, the guide RNA (gRNA) directs Cas13a to the HIV ssRNA, resulting in precise cleavage and viral inhibition.
Importantly, if HIV RNA is absent, the system remains inactive, preventing unintended activity and preserving healthy cellular function.
We envision this platform as a targeted antiviral therapeutic that could be further developed and used by biomedical researchers, clinicians, and global health organizations to combat HIV infection. By combining synthetic biology with precise molecular targeting, our approach represents a step toward programmable, virus-specific treatments that minimize off-target effects and lay the groundwork for future antiviral technologies.