Role of the Lysosome in the Pathogenesis and Therapy of LAM

摘要 淋巴管平滑肌瘤病（LAM）是一种进行性，破坏性的肺部疾病的妇女，可导致氧气 依赖与死亡LAM细胞含有双等位基因失活TSC 2基因突变。的原因 LAM的女性优势和囊性肺破坏的潜在机制尚不清楚， 代表本提案中将解决的关键知识差距。 TSC 1/TSC 2蛋白复合物抑制mTORC 1。TSC信令网络的多个组件可以 定位于溶酶体膜，包括mTOR、Rheb、TSC 1和TSC 2。溶酶体是高度动态的 具有降解和信号传导功能的细胞器，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的“主调节剂”。我们发现TFEB是 在TSC 2缺陷型细胞和人LAM细胞的细胞核中显著升高。溶酶体数量也是 在TSC 2缺陷型细胞中增加，并且LAM细胞具有包括NPC 1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， 基质，可能是LAM肺破坏的原因。我们还发现雌激素强烈地 增加LAM患者来源的细胞中的溶酶体基因表达。 我们的中心假设是LAM细胞中TFEB升高导致溶酶体含量增加， 溶酶体酶进入细胞外间隙，导致肺破坏。我们进一步假设， 雌激素会增强这种作用。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。我们的假设将在四个目标中进行测试： 目标1。确定TFEB如何影响溶酶体胞吐作用和TSC 2缺陷细胞的侵袭潜力。 目标二。确定雌激素影响溶酶体含量和溶酶体胞吐作用的机制 在TSC和LAM中。 目标3：鉴定抑制TSC和LAM中TFEB活性的小分子。 目标4。为了确定TFEB的抑制和/或溶酶体胞吐的抑制如何影响肺损伤， LAM的小鼠模型。 我们预计该项目将通过阐明其机制来产生科学和临床前影响 LAM细胞诱导肺破坏和LAM显著女性优势的原因。

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.