Role of the Lysosome in the Pathogenesis and Therapy of LAM

摘要 淋巴管肌瘤病(LAM)是一种进行性、破坏性的女性肺部疾病，可导致氧气 依赖和死亡。LAM细胞存在双等位基因失活的TSC2基因突变。出现这种情况的原因 女性占优势的LAM和囊性肺破坏的机制尚不清楚， 代表将在本提案中解决的关键知识差距。 TSC1/TSC2蛋白复合体抑制mTORC1。TSC信令网络的多个组件可以 定位于溶酶体膜，包括mTOR、Rheb、TSC1和TSC2。溶酶体是高度动态的 细胞器既具有降解功能，又具有信号传递功能，因此参与许多细胞途径。 TFEB是溶酶体生物发生和溶酶体胞吐作用的“主调节器”。我们发现TFEB是 在TSC2缺陷细胞和人LAM细胞的细胞核中显著升高。溶酶体数也是 在TSC2缺失的细胞中增加，LAM细胞有包括NPC1在内的溶酶体蛋白的显著增加。 溶酶体酶通过溶酶体胞吐作用从溶酶体中释放出来，从而降解细胞外。 可能是LAM肺破坏的原因之一。我们还发现雌激素强烈地 增加LAM患者来源细胞中溶酶体基因的表达。 我们的中心假设是LAM细胞中TFEB的升高导致溶酶体含量增加和释放 溶酶体酶进入细胞外间隙，导致肺破坏。我们进一步假设这些 雌激素会增强效果。一个关键的翻译推论是TFEB和/或溶酶体蛋白是 LAM的潜在治疗靶点。我们的假设将从四个方面进行检验： 目的1.研究TFEB对溶酶体胞吐和TSC2缺陷细胞侵袭潜能的影响。 目的2.确定雌激素影响溶酶体含量和溶酶体胞吐作用的机制 在台湾省和林区。 目的3.鉴定TSC和LAM中抑制TFEB活性的小分子。 目的4.确定抑制TFEB和/或抑制溶酶体胞吐作用对小鼠肺损伤的影响。 LAM的老鼠模型。 我们希望这个项目能够通过阐明 LAM细胞导致肺的破坏，以及LAM以女性为主的原因。

Abstract Lymphangioleiomyomatosis (LAM) is a progressive, destructive lung disease of women that can lead to oxygen dependency and death. LAM cells contain bi-allelic inactivating TSC2 gene mutations. The reasons for the female predominance of LAM and the mechanisms underlying cystic lung destruction are not well understood, representing key knowledge gaps that will be addressed in this proposal. The TSC1/TSC2 protein complex inhibits mTORC1. Multiple components of the TSC signaling network can localize to the lysosomal membrane, including mTOR, Rheb, TSC1, and TSC2. Lysosomes are highly dynamic organelles with both degradation and signaling functions, thus participating in many cellular pathways. TFEB is a “master regulator” of lysosomal biogenesis and lysosomal exocytosis. We have found that TFEB is markedly elevated in the nucleus of TSC2-deficient cells and in human LAM cells. Lysosomal number is also increased in TSC2-deficient cells, and LAM cells have a striking increase in lysosomal proteins including NPC1. Lysosomal enzymes are released from the lysosomes through lysosomal exocytosis, which degrade extracellular matrix, and could be a cause of lung destruction in LAM. We have also discovered that estrogen strongly increases lysosomal gene expression in LAM patient-derived cells. Our central hypothesis is that elevated TFEB in LAM cells leads to increased lysosomal content and the release of lysosomal enzymes into the extracellular space, leading to lung destruction. We further hypothesize that these effects are enhanced by estrogen. A key translational corollary is that TFEB and/or lysosomal proteins are potential therapeutic targets for LAM. Our hypotheses will be tested in four Aims: Aim 1. To determine how TFEB impacts lysosomal exocytosis and the invasive potential of TSC2-deficient cells. Aim 2. To determine the mechanism through which estrogen affects lysosomal content and lysosomal exocytosis in TSC and LAM. Aim 3. To identify small molecules that inhibit the activity of TFEB in TSC and LAM. Aim 4. To determine how inhibition of TFEB and/or inhibition of lysosomal exocytosis impact lung destruction in a mouse model of LAM. We expect this project to have scientific and preclinical impact by elucidating the mechanisms through which LAM cells induce lung destruction and the reasons for the striking female predominance of LAM.