Moving a novel gene therapy paradigm to treat  blindness to the market
At present therapies for inherited dominant disorders are not available, thus representing an urgent unmet medical and social need. The ERC Grant ALLELECHOKER enabled the PI to discover three modes to generate transcriptional repression by transcription factors (TFs) based on Zinc-finger scaffold: i- synthetic transcription factor (TF; Mussolino et al., EMBO Mol. Med. 2011 Mar;3(3):118-28; Botta S. et al. Elife. 2016 Mar 14;5), ii- synthetic DNA-binding protein (Botta S. et al. Elife. 2016 Mar 14;5) and iii- the ectopic expression of an endogenous TF (Botta S, et al. JCI Insight. 2017 Dec 21;2(24). Thus, the PI demonstrated that transcriptional repression by TFs embodies a novel therapeutically effective mode to treat the toxic effects of gain-of-function mutations causing incurable inherited dominant disorders. In particular, mutations in the RHODOPSIN gene can cause the blindness disorder autosomal dominant retinitis pigmentosa (adRP). The PI demonstrated safety and efficiency of RHODOPSIN gene transcriptional silencing in pre-clinical animal models by a specific synthetic transcriptional repressor (ZF6-DB) delivered to the retina by an adeno-associated virus (AAV) vector (AAV-ZF6-DB). Furthermore, within the ERC Grant ALLELECHOKER the PI showed that a single AAV vector containing two independent expression cassettes (AAV-ZF6-DB-hRHO), enables balanced silencing of RHODOPSIN by ZF6-DB and its simultaneous replacement with a human wild-type copy of the RHODOPSIN gene. The primary objective of the inSight ERC-PoC grant is to support AAV-ZF6-DB-hRHO clinical translation, with the final goal of bringing this therapeutic to patients suffering adRP through market authorization and commercialization.