Cpf1-mediated inactivation of an AAV transgene

PROJECT SUMMARY The Farzan laboratory has developed what appears to be an effective way to prevent HIVinfectionThis approach combines eCDIgan exceptionally broad and potent HIVentry inhibitorwith an adenoassociated virusAAVdelivery systemFor more than a year after a one time intramuscular inoculation with AAV eCDIgrhesus macaques were protected against multiple high dose intravenous challenges with SHIV ADand SIVmacAAV vectors have the potential to persist in muscle for a lifetimeThis longevity is an important advantage of the AAV systembut also poses risksSpecificallywhile it is likely that eCDIg is safeit has not yet been expressed in large numbers of people or for long periods of timeand there is no easy way to undo AAV administration in case of adverse eventsTo that endwe seek here to develop a practical means of halting the expression of an AAV transgeneWe propose optimizing AAV vectors to be efficiently inactivated upon the administration of lipid nanoparticlesLNPscontaining a modified mRNA that encodes the CRISPR effector protein CpfThe optimized system for shutting off AAV transgene expression will then be tested in miceThis work will allow us to include an off switch in AAV vectors when they are tested in humansA practical means for turning off eCDIg expression by AAV will improve the safety of an effective approach for treating or preventing HIVinfection PROJECT NARRATIVE Expression of a potent HIVentry inhibitor by gene therapy could provide long term vaccine like protection from HIVinfectionHere we seek to develop one way of inactivating expression of this inhibitor in case of adverse eventsthereby improving the safety of a candidate HIVvaccine