Genetically engineered human cortical spheroid models of tuberous sclerosis

Area of Science:

• Neuroscience
• Genetics
• Developmental Biology

Background:

• Tuberous sclerosis complex (TSC) is a genetic disorder affecting multiple organs.
• TSC is characterized by cortical tubers, linked to epilepsy.
• Mutations in TSC1 or TSC2 genes disrupt mTORC1 signaling.

Purpose of the Study:

• To investigate the developmental origin of cortical tubers in TSC.
• To create human cellular models of TSC using gene editing.
• To understand the role of genetic hits in tuber formation.

Main Methods:

• CRISPR-Cas9 gene editing in human pluripotent stem cells (hPSCs).
• Creation of heterozygous TSC2 hPSCs with conditional mutations.
• Analysis of three-dimensional cortical spheroids to model TSC.

Main Results:

• Mosaic biallelic inactivation of TSC genes during neural progenitor expansion is required for tuber cell formation.
• Dysplastic cell formation and increased glial production were observed.
• Findings support the second-hit model for cortical tuber development.

Conclusions:

• Somatic mutations in TSC genes during development contribute to cortical tuber formation.
• Variable timing of these secondary hits may explain neurological heterogeneity in TSC patients.