# KCNB1 mutation impairs neuronal differentiation by disrupting gene expression temporal regulation and neuron-specific pathways

## TL;DR

A KCNB1 mutation disrupts how stem cells become neurons by altering gene activity timing and key brain pathways.

## Contribution

The study reveals how KCNB1 mutations specifically affect gene expression timing and neuron-specific pathways during differentiation.

## Key findings

- KCNB1 mutant neurons show lower KCNB1 expression compared to healthy neurons.
- Patient neurons lack synapse-related pathways and show enrichment in basic metabolism pathways.
- KCNB1 mutation disrupts temporal gene expression patterns and neuron-specific pathways during differentiation.

## Abstract

This study aims to rigorously evaluate the consistency and reliability of a pluripotent stem cell (PSC) differentiation system and explore how the KCNB1 mutation disrupts the temporal regulation of gene expression during neuronal differentiation and modulates neuron function-related pathways.

Induced pluripotent stem cells (iPSCs) derived from a patient carrying a KCNB1 variant (c.990G > T, p.Glu330Asp) and from a healthy donor were differentiated into neurons. Differentiation and RNA expression were assessed at multiple time points. Immunofluorescence, RNA sequencing, fuzzy c-means clustering, and pathway analyses were performed.

The differentiation system was successfully established, with cells exhibiting stage-appropriate morphology and maturing into neurons. RNA sequencing revealed consistent gene expression patterns at the neural progenitor cell (NPC) stage but significant differences at the neuron stage between the KCNB1 mutant patient and the healthy donor. Notably, KCNB1 expression was lower in the patient’s neurons. Genes specifically clustered in healthy neurons were enriched in synapse-related pathways, while genes clustered in patient neurons were associated primarily with basic cellular metabolism pathways and abolished neuron-specific pathways.

Low expression of KCNB1 disrupts the temporal pattern of gene expression and related neuron-specific pathways during neuronal differentiation and impairs neuronal differentiation and maturity.