Effects of TBCK deficiency, responsible for IHPRF3 Neurodegenerative Syndrome, on the neural differentiation process

• Grant number: 23/02551-6
• Support Opportunities: Scholarships in Brazil - Doctorate (Direct)
• Start date: October 01, 2023
• End date: May 31, 2027
• Field of knowledge: Biological Sciences - Genetics - Human and Medical Genetics
• Principal Investigator: Maria Rita dos Santos e Passos Bueno
• Grantee: Igor Cabreira Ramos
• Host Institution: Instituto de Biociências (IB). Universidade de São Paulo (USP). São Paulo , SP, Brazil
• Associated research grant: 13/08028-1 - CEGH-CEL - Human Genome and Stem Cell Research Center, AP.CEPID

Abstract

TBCK (TBC1 domain-containing kinase) codes for a kinase protein allegedly associated to vesicle transport (autophagic-lysosomic pathway), cellular growth, actin cytoskeleton organization, transcriptional mTOR regulation and axonal transport of mRNA and translation machinery. Biallelic loss-of-function variants in TBCK are causative of the Infantile Hypotonia with Psychomotor Retardation and Characteristic Facies 3 (IHPRF3), frequently characterized by neurodegeneration and premature death. Previous work with fibroblasts and neural cells harboring homozygous TBCK variants report alterations in the mTOR pathway, in intracellular transport, autophagosome biogenesis, cell proliferation and migration. Preliminary data from our lab suggest that TBCK-defficient cells present altered expression of neurodevelopment markers. Our hypothesis is that TBCK defficiency contributes to the dysregulation of neuroprogenitor populations, resulting in altered neural differentiation and skewed proportion ou neural subpopulations. In order to assess how the absence of TBCK affects the neural differentiation, control and mutant cell lines, induced with CRISPR-Cas9 will be cultured in 2D and 3D (organoid) systems. Our experiments intend to evaluate progenitor proliferation, cell fate proportions, electrophysiological alterations and differentially expressed genes. After analyzing our results, we hope to contribute in the elucidation of the underlying molecular mechanisms of disorders as IHPRF3. (AU)