Laboratory for Molecular Biodiscovery, Department of Pharmaceutical and Pharmacological Sciences, University of Leuven, Leuven, Belgium.
Department of (Neuro) Pathology, Academic Medical Center and Swammerdam Institute for Life Sciences, Center for Neuroscience, University of Amsterdam, Amsterdam, Stichting Epilepsie Instellingen Nederland (SEIN), The Netherlands.
Neurobiol Dis. 2017 Dec;108:225-237. doi: 10.1016/j.nbd.2017.09.004. Epub 2017 Sep 6.
Tuberous sclerosis complex (TSC) is a rare, genetic disease caused by loss-of-function mutations in either TSC1 or TSC2. Patients with TSC are neurologically characterized by the presence of abnormal brain structure, intractable epilepsy and TSC-associated neuropsychiatric disorders. Given the lack of effective long-term treatments for TSC, there is a need to gain greater insight into TSC-related pathophysiology and to identify and develop new treatments. In this work we show that homozygous tsc2 mutant zebrafish larvae, but not tsc2 and WT larvae, display enlarged brains, reduced locomotor behavior and epileptiform discharges at 7dpf. In addition, we pharmacologically validated the TSC model by demonstrating the dramatic rescue effect of pericardially injected rapamycin, a well-known mTOR inhibitor, on selected behavioral read-outs and at the molecular level. By means of trancriptome profiling we also acquired more insight into the neuropathology of TSC, and as a result were able to highlight possible new treatment targets. The gene expression profiles of WT and tsc2 larvae revealed 117 differentially expressed genes (DEGs), while between WT and tsc2 larvae and tsc2 and tsc2 larvae there were 1414 and 1079 DEGs, respectively. Pathway enrichment analysis from the WT and tsc2 DEGs, identified 14 enriched pathways from the up-regulated genes and 6 enriched pathways from the down-regulated genes. Moreover, genes related to inflammation and immune response were up-regulated in the heads of tsc2 larvae, in line with the findings in human brain tissue where inflammatory and immune responses appear to be major hallmarks of TSC. Taken together, our phenotypic, transcriptomic and pharmacological analysis identified the tsc2 zebrafish as a preclinical model that mirrors well aspects of the human condition and delineated relevant TSC-related biological pathways. The model may be of value for future TSC-related drug discovery and development programs.
结节性硬化症（TSC）是一种罕见的遗传性疾病，由 TSC1 或 TSC2 的功能丧失性突变引起。TSC 患者的神经特征为异常的大脑结构、难治性癫痫和 TSC 相关的神经精神障碍。鉴于缺乏有效的 TSC 长期治疗方法，因此需要更深入地了解 TSC 相关的病理生理学，并确定和开发新的治疗方法。在这项工作中，我们发现纯合 tsc2 突变的斑马鱼幼虫，而不是 tsc2 和 WT 幼虫，在 7dpf 时表现出大脑增大、运动行为减少和癫痫样放电。此外，我们通过证明心包内注射雷帕霉素（一种众所周知的 mTOR 抑制剂）对选定的行为读数和分子水平具有显著的挽救作用，从而对 TSC 模型进行了药理学验证。通过转录组谱分析，我们还更深入地了解了 TSC 的神经病理学，并因此能够突出可能的新治疗靶点。WT 和 tsc2 幼虫的基因表达谱显示 117 个差异表达基因（DEGs），而 WT 和 tsc2 幼虫之间以及 tsc2 和 tsc2 幼虫之间分别有 1414 个和 1079 个 DEGs。WT 和 tsc2 DEGs 的通路富集分析，从上调基因中鉴定出 14 个富集通路，从下调基因中鉴定出 6 个富集通路。此外，在 tsc2 幼虫的头部上调了与炎症和免疫反应相关的基因，这与人类脑组织中的发现一致，在人类脑组织中，炎症和免疫反应似乎是 TSC 的主要特征。总之，我们的表型、转录组和药理学分析将 tsc2 斑马鱼鉴定为一种临床前模型，很好地反映了人类疾病的某些方面，并阐明了相关的 TSC 相关生物学途径。该模型可能对未来的 TSC 相关药物发现和开发计划具有价值。
