Umbach, A. | Search bioRxiv

bioRxiv2026

ARHGEF6-dependent cytoskeletal regulation underlies a conserved program of forebrain interneuron development

The molecular programs coordinating inhibitory interneuron migration, maturation, and survival during forebrain development remain incompletely understood. Here we investigate ARHGEF6, a RAC1/CDC42 guanine nucleotide exchange factor linked to X-linked intellectual disability (XLID46) and previously studied only at postsynaptic compartments, and reveal an earlier, conserved role in forebrain interneuron development. ARHGEF6 is selectively enriched in the inhibitory lineage during the peak of interneuron generation and migration. Its loss in mice reduces the number of cortical and hippocampal interneurons, disrupts tangential migration, increases developmental cell death, and impairs morphological and electrophysiological maturation. Strikingly, ARHGEF6-knockout human iPSC-derived organoids and assembloids mirror these deficits exhibiting increased apoptosis, reduced neuronal output, disorganized growth cones, impaired neurite branching, and disrupted migratory dynamics. These cross-species findings reframe ARHGEF6 as an early, essential orchestrator of inhibitory circuit assembly and reveal a conserved cytoskeletal program whose disruption produces the excitatory-inhibitory imbalance linked to cognitive dysfunction.

developmental biology↗

bioRxiv2024

Functional rescue of F508del-CFTR through revertant mutations introduced by CRISPR base editing

Cystic Fibrosis (CF) is a life-shortening autosomal recessive disease caused by mutations in the CFTR gene, resulting in functional impairment of the encoded ion channel. F508del mutation, a trinucleotide deletion, is the most frequent cause of CF affecting approximately 80% of patients. Even though current pharmacological treatments alleviate the F508del-CF disease symptoms there is no definitive cure. Here we leveraged revertant mutations (RMs) in cis with F508del to rescue CFTR protein folding and restore its function. We developed CRISPR base editing strategies to efficiently and precisely introduce the desired mutations in the F508del locus. Both editing and CFTR function recovery were verified in CF cellular models including primary epithelial cells derived from CF patients. The efficacy of the CFTR recovery strategy was validated in cultures of pseudostratified epithelia from patients cells showing full recovery of ion transport. Additionally, we observed an additive effect by combining our strategy with small molecules that enhance F508del activity, thus paving the way to combinatorial therapies.

bioengineering↗