AbstractHuman immunodeficiency virus type I (HIV-1) is a global health issue affecting approximately 35 million people worldwide. Despite the success of highly active antiretroviral therapy (HAART), drug resistant viruses and adverse drug reactions raise the need for new classes of antiretroviral drugs. During HIV-1 replication, the viral frameshifting element orchestrates expression of a specific ratio of the essential Gag and Gag-Pol polyproteins from overlapping reading frames. This process is vital for viral assembly and maturation, since altering the ratio of Gag and Gag-Pol polyproteins through HIV-1 frameshifting, perturbs HIV-1 replication.
To identify modulators of HIV-1 frameshifting, a bi-cistronic fluorescent construct was designed to establish a clonally-derived cell culture model of HIV-1 Gag:Gag-Pol frameshifting. Following assay development and validation of screening parameters, a primary diversity screen with 92,071 small molecules was conducted. The initial screening triage of hit compounds led to the selection of several false positives due to auto-fluorescent compound properties. I subsequently re-designed the screening cascade to incorporate a counter-screen that was effective at eliminating false positives. Ultimately, no hit compounds were identified capable of activating or inhibiting HIV-1 frameshifting.
However, compound DDD00049811 was fortuitously discovered to inhibit the spread of HIV-1 infection, but not through the desired target of HIV-1 frameshifting. The high concentration required to elicit an antiviral response, the minimal effect in a single-cycle of HIV-1 replication and the slight cellular viability defect suggest that DDD00049811 is not a good anti-HIV-1 candidate drug. My work indicates that HIV-1 frameshifting is a challenging drug target; however, addressing limitations in the strategy used in this study could allow this critical function to be drugged successfully.
|Date of Award
|David Gray (Supervisor) & Sam Wilson (Supervisor)