SEMA-gene modulation as a strategy to identify druggable targets for the treatment of CHARGE syndrome

CHARGE syndrome (CS) is a rare genetic disease, mainly due to mutations in the chromatin remodeler gene CHD7 and characterized by multiple neuronal dysfunctions and malformations of neural-crest derived organs, for which no pharmacological treatments are available. CS high phenotypic variability could be explained by mutations in genes with an epistatic relationship to CHD7, that may alter the expressivity of disease traits. In this context, recent evidence revealed that genes encoding semaphorins (SEMA) and their receptors might be good candidates as CHD7 genetic interactors. Thus, we generated a tailored pipeline that combines the power of a Caenorhabditis elegans (C. elegans) chd-7 mutant with a genome-edited neuronal line to identify drugs able to bypass CHD7 deficiency and modulate target SEMA genes. In vivo, several developmental phenotypes of C. elegans chd-7deletion mutants were evaluated to set-up an epi-drug pharmacological screening, that preliminary revealed hits able to rescue the aberrant reproductive phenotype of mutant worms. Candidate hits will be further tested to identify molecules able to restore physiological levels of Sema-genes expression, altered in mutants. In vitro, we generated a Chd7-knock-out (KO) mouse neuronal CS model applying CRISPR/Cas9 technique. KO clones interestingly revealed cellular and genetic signatures related to altered cell migration and proliferation pathways. The identified biological behaviors and gene expression patterns will be next employed as read-out end points in future pharmacological screenings with hit compounds identified in vivo. Overall, these results will highlight molecules potentially able to target deregulated downstream genes in CS patients, by-passing CHD7 haploinsufficiency.