Regulation of Lipid Catabolism by Autophagy in Neural Stem Cell of Tuberous Sclerosis Complex

结节性硬化症(TSC)是一种遗传性疾病，在美国有多达5万人受到影响。台糖公司 经常通过癫痫发作、自闭症、智力不稳定和非癌症(良性)肿瘤的生长来影响大脑。 这些缺陷持续存在于TSC患者的新生儿和成人大脑中。TSC1或TSC2基因突变的研究 导致其肿瘤抑制功能的丧失是控制mTORC1活性的基础 TSC的发病机制。MTORC1是一种公认的细胞内稳态的主调节器，并刺激 翻译的活性，但负向调节自噬，这是一种保守的分解代谢过程，可降解 溶酶体中的细胞质成分和细胞器。有趣的是，我们最近的发现揭示了 在能量应激条件下，TSC1缺陷细胞中更高的自噬活性，导致建立 一种新的缺失TSC1和FIP200(Fak相互作用蛋白)的双条件基因敲除(CKO)小鼠模型 200kD，这是自噬诱导复合体的重要组成部分)。 利用这个独特的模型，我们揭示了自噬维持mTORC1高活性的基本功能 TSC1缺陷型NSC的出生后发育异常。此外，我们发现自噬是 线粒体氧化磷酸化所需的，以抵抗能量应激条件，很可能提供 细胞内脂肪储存产生三磷酸腺苷的游离脂肪酸。这些试点调查结果构成了我们 自噬介导神经干细胞β氧化和三磷酸腺苷脂类降解的假说 生产以维持其高mTORC1活性，这为TSC提供了一个有价值的代谢靶点 病人。在本提案的目的1中，我们将检验自噬的分子和代谢机制。 脂类降解和脂噬功能调节高mTORC1活性的信号通路， 使用原始性和差别性NSC。在AIM2中，我们将使用我们新开发的FIP200条件 与Atg13结合缺陷的Knockin小鼠产生TSC1/FIP200 2cKI小鼠。这种遗传工具 将进一步阐明TSC1基因缺陷的神经干细胞的吞脂机制。我们还将采用药理学 方法靶向自噬介导的脂质分解代谢来治疗出生后TSC1缺陷的神经干细胞。在……里面 Aim3，我们将建立新的可诱导的小鼠模型，在出生后特异性地消耗TSC1和FIP200 国家安全委员会。我们还将使用这些小鼠模型来治疗现有的SEN/SEGA，这在临床上更相关， AIM2的补体研究。在这些研究结束后，我们将扩大我们对发病机制的认识 TSC缺陷的NSC，通过过度激活识别候选信号通路和代谢变化 MTORC1，并为脑治疗的持续研究开发新的治疗概念 TSC患者的发育障碍。

Tuberous sclerosis complex (TSC) is a genetic disorder affects as many as 50,000 people in US. TSC often affects brain by seizures, autism, intelligence instability and growth of noncancerous (benign) tumors. These defects persist in neonatal and adult brains of TSC patients. The mutations of Tsc1 or Tsc2 gene leading to the loss of their tumor suppressor functions to control the activity of mTORC1 underlie the pathogenesis of TSC. mTORC1 is an established master regulator of cellular homeostasis and stimulates the activity of translation but negatively regulate autophagy, a conserved catabolic process that degrades cytoplasmic constituents and organelles in the lysosome. Interestingly, ours recent findings revealed a higher autophagy activity in Tsc1-deficient cells under energy stress conditions, leading to establishment of a novel double conditional knockout (cKO) mouse model to delete TSC1 and FIP200 (Fak interaction protein of 200 KD, an essential component in autophagy induction complex) in postnatal neural stem cells (NSC). Using this unique model, we revealed the essential functions of autophagy to sustain high mTORC1 activity and in abnormal postnatal development of Tsc1-deficient NSC. In addition, we found that autophagy was required for mitochondria oxidative phosphorylation to resist energy-stress conditions, most likely providing free fatty acids to generate ATP from intracellular lipid storage. These pilot findings form the basis of our hypothesis that autophagy mediates the lipids degradation in Tsc1-deficient NSC for β-oxidation and ATP production to maintain their high mTORC1 activity, which provide a valuable metabolic target for TSC patients. In Aim1 of this proposal, we will exam the molecular and metabolic mechanisms of autophagy in lipid degradation and the functions of lipophagy to regulate signaling pathways for high mTORC1 activity, using primitive and differentiating NSC. In Aim2, we will use our newly developed FIP200 conditional knockin mouse which is defective in binding with Atg13 to generate Tsc1/Fip200 2cKI mice. This genetic tool will further clarify the mechanisms of lipophagy in Tsc1-deficient NSC. We will also adopt pharmacological methods to target autophagy mediated lipid catabolism to treat defects in postnatal Tsc1-deficient NSC. In Aim3, we will generate novel inducible mouse models to specifically deplete Tsc1 and Fip200 in postnatal NSC. We will also use these mouse models to treat existing SEN/SEGA, which is more clinically relevant, to complement studies in Aim2. At the end of these studies, we will expand our knowledge of pathogenesis in TSC-deficient NSC, identify candidate signaling pathways and metabolic alterations by hyperactivated mTORC1, and develop new therapeutic concepts for continued investigation in the treatment of brain development disorders in TSC patients.