Manipulation of the expression of a secreted isoform of neurexin-3 in neurons derived from patients with an autism spectrum syndrome

• Grant number: 25/22941-9
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: January 01, 2026
• End date: December 31, 2026
• Field of knowledge: Biological Sciences - Biochemistry - Molecular Biology
• Principal Investigator: Fabio Papes
• Grantee: Lilian Lee Depieri
• Host Institution: Instituto de Biologia (IB). Universidade Estadual de Campinas (UNICAMP). Campinas , SP, Brazil
• Associated research grant: 22/12762-1 - Investigation of alterations in neuronal migration in an autism spectrum disorder using human cellular models and animal models, AP.TEM

Abstract

Pitt-Hopkins Syndrome (PTHS), the focus of this project, is a monogenic autism spectrum disorder (ASD) and is caused by haploinsufficiency of the TCF4 gene. In addition to the altered expression of this gene, preliminary results from our group have identified dysregulation in the expression of RBFOX1 and NOVA1, which encode RNA splicing regulatory proteins. Based on RNA-seq data obtained from neuronal cultures derived from PTHS patients and control individuals, we performed bioinformatic analyses to investigate aberrant splicing events associated with neurodevelopmental genes. These analyses identified an exon-skipping event in the NRXN3 gene, resulting in the formation of a soluble form of the neurexin-3 protein, distinct from the transmembrane protein isoform encoded by the canonical transcript of this gene. Furthermore, our analyses indicated that the soluble isoform occurs predominantly in control cells compared to patient cells. The present project aims to understand the function of this soluble neurexin-3 in the context of this type of monogenic autism, particularly regarding its possible involvement in synaptic organization. To this end, the expression of the transcript encoding the soluble isoform will be silenced in control neuronal cells, followed by molecular and physiological evaluation of synapses. Complementarily, PTHS neuronal cultures will be treated with the soluble neurexin-3 isoform to assess whether this treatment restores synaptic activity in the diseased neural tissue.