Patients with Tuberous Sclerosis Complex (TSC) show aberrant wiring of neuronal connections formed during development which may contribute to symptoms of TSC, such as intellectual disabilities, autism, and epilepsy. Yet models examining the molecular basis for axonal guidance defects in developing human neurons have not been developed. Here, we generate human induced pluripotent stem cell (hiPSC) lines from a patient with TSC and genetically engineer counterparts and isogenic controls. By differentiating hiPSCs, we show that control neurons respond to canonical guidance cues as predicted. Conversely, neurons with heterozygous loss of TSC2 exhibit reduced responses to several repulsive cues and defective axon guidance. While TSC2 is a known key negative regulator of MTOR-dependent protein synthesis, we find that TSC2 signaled through MTOR-independent RHOA in growth cones. Our results suggest that neural network connectivity defects in patients with TSC may result from defects in RHOA-mediated regulation of cytoskeletal dynamics during neuronal development.

患有结节性硬化症 (TSC) 的患者表现出在发育过程中形成的神经元连接的异常布线，这可能导致 TSC 的症状，例如智力障碍、自闭症和癫痫。然而，尚未开发出用于检查发育中的人类神经元中轴突导向缺陷的分子基础的模型。在这里，我们从患有 TSC 的患者和基因工程对应物和同基因对照中生成人类诱导多能干细胞 (hiPSC) 系。通过区分 hiPSC，我们表明控制神经元对预测的规范指导线索做出反应。相反，TSC2 杂合缺失的神经元对几种排斥性线索和轴突引导缺陷的反应减弱。虽然 TSC2 是已知的 MTOR 依赖性蛋白质合成的关键负调节因子，我们发现 TSC2 通过生长锥中独立于 MTOR 的 RHOA 发出信号。我们的研究结果表明，TSC 患者的神经网络连接缺陷可能是由于神经元发育过程中 RHOA 介导的细胞骨架动力学调节缺陷所致。