Non-cell autonomous effects of second hit variants in organoids and cortical tubers in Tuberous Sclerosis Complex
Year: 2026
Type: dataset
Abstract: Structural abnormalities are common causes of refractory epilepsy, and while progress has been made in understanding the genetic changes associated with these malformations, the pathogenic mechanisms often remain unclear. Dysregulation of the mechanistic target of rapamycin (mTOR) pathway contributes to a subset of focal cortical dysplasia types, including malformations observed in patients with Tuberous Sclerosis Complex (TSC). Heterozygous inactivating variants in TSC1 or TSC2 are sufficient to cause this disease, but second hit variants in these genes have been identified in nearly all pathological lesions associated with TSC. However, most cortical malformations in TSC do not have second hit variants, and therefore, a critical question is whether these genetic changes are necessary for their development. We used organoids generated from heterozygous patient-derived induced pluripotent stem cells and isogenic stem cells with second hit variants, and we demonstrated that null cells secrete factors that impair cortical neuron differentiation of neighboring cells by inhibiting the transcriptional coactivator YAP1. Knockdown of one specific factor, AMOT, in null cells rescued neuronal differentiation and YAP1 expression. Finally, we analyzed cell type specific gene expression in malformations in patients with TSC and observed similar patterns of dysregulation to those identified in organoids. These data define a novel pathogenic mechanism underlying the development of focal brain malformations in TSC and related mTORopathies, which will aid in understanding the epileptogenicity of these lesions.
Source: Harvard Dataverse
DOI: 10.7910/dvn/cx7kfc
Author: Winden, Kellen
Institution: Harvard University
Language: English
Subfield: Genetics (clinical)
Field: Medicine
Domain: Health Sciences
Open Access status: green
OpenAlex ID: W7167494054