Convergent and Divergent Molecular Pathways in FMR1, TSC2, and double Knockout iPSC-Derived Neurons

FXS results from the loss of FMRP, an RNA-binding protein that regulates synaptic protein synthesis, while TSC arises from mutations in TSC1 or TSC2, leading to hyperactive mTOR signaling. Although TSC2 deficiency has been shown to accelerate FMRP degradation, the extent to which these proteins converge within shared pathways remains unclear, particularly given their markedly different phenotypic outcomes.

To investigate the convergence and divergence of FMRP and TSC2 in regulating neuronal function, we generated single and double knockout (dKO) human pluripotent stem cells (hPSCs) using CRISPR/Cas9 system. Global molecular profiling revealed distinct and overlapping gene expression changes, highlighting shared dysregulation of translational control pathways, while also uncovering unique compensatory mechanisms in single knockouts.