Among the mutations of the Cystic Fibrosis Transconductance Regulator (CFTR) gene, causing cystic fibrosis (CF), nonsense mutations are the second most diffuse mutations. In particular, in Italy, about 20,5% of people with CF have a stop mutation. A proposed approach restoring the nonsense mutated CFTR gene is translational readthrough of premature termination codons (PTCs) by Translational Read-Through-Inducing Drugs (TRIDs). 

Based on the results of the projects FFC#1/2014 and FFC#3/2017, by computational and biological screening, the researchers identified three new small molecules showing high readthrough activity and low toxicity in vitro and in vivo (zebrafish). 

The main scope of this project was to assess the molecules toxicity and the biodistribution in vivo, to evaluate CFTR expression and functionality after treatment with TRIDs in vivo and in CF organoids. A side objective was to study the possible mechanism of action.
An acute toxicological study for the three TRIDs was conducted in vivo on CFTR-wild type mice. Their biodistribution was also assessed.
Analysis of CFTR expression and functionality after treatment with NV TRIDs was conducted in CFTR-stop mutations mouse model and in human CF intestinal organoids carrying nonsense CFTR mutations. A computational evaluation of the TRIDs biological targets and MOA was performed.
The results showed a good metabolic stability and biodistribution of the three molecules. Moreover, a moderate rescue of the CFTR activity was observed in CF organoids with W1282X-CFTR in combination with CFTR modulators. Finally, a possible biological target of the NV molecules was explored, indicating that the FTSJ1 protein could be involved in the readthrough process induced by our TRIDs.
These findings have translational potential and provide the validation of molecules with readthrough activity for the rescue of the CFTR function.