The aim of this proposal was to test the efficacy of compounds that modify gene expression (histone deacetylase inhibitors) as potential treatments for Autism Spectrum Disorders (ASD). ASD comprise a very diverse group of clinical phenotypes caused by alterations in human DNA that generally trigger language impairment, intellectual disability, anxiety, communication impairments and stereotypies. To date, more than 900 different alterations in our genes have been identified causing ASD and among them, epigenetic regulators play a prominent role suggesting that compounds targeting those regulators may be potential treatments for ASD. Here, we focused on one of the best characterized ASD syndromes, caused by alterations in the number of 26-28 genes (copy number variation, CNVs) at the chromosome 7. The duplication of 7q11.23 region of chromosome 7 (patients with more than 2 gene copies; 7Dup) has been associated with language impairments, anxiety, attention deficit hyperactivity disorder (ADHD) and sociality impairments, all traits of autism spectrum. 7Dup offers unique translational opportunities because hemideletion (patients that have only one copy of the same genes duplicated above) causes Williams-Beuren syndrome (WBS), a condition characterized by symmetrically opposite behavioral phenotypes including hypersociability in the face of well-preserved language abilities, thereby providing a unique reference standard to validate treatments for the core ASD symptoms. Studies in patients and in animals have identified gene GTF2I as critical for its role in cognitive-behavioral phenotypes observed in 7Dup and WBS syndromeS. Previously, we identified a class of compounds (HDAC inhibitors) that could reduce the abnormal levels of GTF2I expression in neurons and brain organoids- 3D structures that resemble the human brain- from 7Dup patients. Here, we tested the activity of three different compounds-already under investigation in clinical studies for other pathologies-to identify the most effective compound that could potentially treat 7Dup and more broadly ASD clinical symptoms. In this regard, we measured GTF2I gene expression and its protein levels as well as the impact of the compounds on cell viability and cytotoxicit. In addition, we assessed the efficacy of compounds in patient-derived brain organoids treated for 15 days and identified SAHA as the most efficacious compound. Specifically, SAHA showed the highest efficacy in restoring normal levels of GTF2I gene expression and its protein coupled with modest effects on cell viability and cytotoxicity. Given the promising impact of SAHA on cellular models from patients, we tested its effects on a mouse model of 7Dup that similarly to 7Dup patients harbor a duplication of GTF2I. Administration of SAHA, following a previously determined dosage regiment, reversed mouse deficits in social novelty but did not show a strong effect on social preference of GTF2IDup mice, two surrogates of sociality impairments of 7Dup and ASD patients. Importantly, in order to facilitate the translation of the experimental results into potential effective therapies for the patients, we first protected the Intellectual Property arisen from the project by filing a patent application for the use of HDAC inhibitors in ASD and 7Dup. Furthermore, we conducted business exploitation activities aimed at i) seeking investments for the creation of a new vehicle focused on the development of epigenetic modulators for ASD and 7Dup; 2) establishing co-development partnerships with pharmaceutical companies owing and interested in repurposing such compounds for ASD and 7Dup. Given the unmet medical need in ASD and the significant economic and social impact of managing rare diseases like 7Dup, these exploitation outcomes will help in developing new effective therapies for autistic patients with a great benefit to economy and society.
