Uterine signaling networks in the pathogenesis of pulmonary lymphangioleiomyomatosis (LAM)

项目摘要 淋巴管平滑肌瘤病（LAM）是一种影响育龄妇女的肺肿瘤，是由 结节性硬化症1（TSC 1）或TSC 2基因的功能突变。机械靶点的过度激活 雷帕霉素1导致囊性肺重塑和进行性呼吸衰竭。西罗莫司治疗稳定肺 功能并改善LAM患者的症状，但长期获益和毒性尚不清楚， 患者对治疗没有反应。LAM细胞是转移性的，但原发组织来源不明。 LAM的肺特异性转移、主要发病机制和女性患病率的未知机制 是发展新的治疗方法的障碍。我们从LAM肺单细胞的初步数据 RNA测序（scRNAseq）分析鉴定了表达子宫内膜癌的独特细胞群（LAMCORE）。 在正常肺中未检测到的特异性同源框（HOX）转录因子（TF）; LAM的TF谱 患者来源的细胞鉴定出前B细胞白血病同源框1（PBX 1）的活化，PBX 1是HOX的辅因子; LAM肺scRNAseq和乳腺癌细胞PBX 1-ChIPseq的比较分析显示， 具有阳性PBX 1结合峰的LAMCORE标记基因。总的来说，这强烈表明子宫起源 和HOX/PBX 1信号在LAM发病机制中的核心作用。本提案的目的是 确定HOX相关基因网络调节LAM发病和进展的机制。 我们的中心假设是HOX/PBX 1协调了女性生殖系统下游的细胞特异性基因网络。 调节LAMCORE细胞存活和肺转移的激素。提出了三个具体目标， 阐明HOX/PBX 1基因网络参与LAM病变的分子机制 转移、形成和进展。目的1：确定肺LAM特异性基因组和表观基因组 HOX/PBX 1介导的LAM发病机制的反应和机制。目标2：确定 HOX/PBX 1网络基因在体外和体内对LAM衍生细胞转移潜能的功能影响。 目的3：确定HOX/PBX 1拮抗剂HXR 9单独或与西罗莫司联合对HXR/PBX 1受体的作用。 雌激素促进体内肺转移潜能和肺重塑。完成这项提案 将首次提供：1）LAMCORE的高分辨率整合基因组/表观基因组蓝图 2）LAMCORE细胞特异性HOX/PBX 1基因网络，其具有预测的关键调控因子和靶点， 用于后续扰动和临床诊断测试的网络，3）对HOX/PBX 1的新机制见解 调节回路及其对LAM发病机制的功能影响，以及4）临床前原理证据 用于靶向HOX/PBX 1调节的女性乳腺癌介导的LAM进展，作为一种新的缓解诱导 LAM患者的治疗策略。我们的工作对于理解LAM具有重要的生物医学意义 发病机制，开发LAM诊断的新方法和设计替代缓解诱导 治疗策略，以最大限度地提高效益/毒性比LAM治疗。

PROJECT SUMMARY Lymphangioleiomyomatosis (LAM), a lung neoplasm affecting reproductive age women, is caused by loss-of- function mutations in tuberous sclerosis 1 (TSC1) or TSC2 genes. Hyperactivation of the mechanistic target of rapamycin 1 leads to cystic lung remodeling and progressive respiratory failure. Sirolimus therapy stabilizes lung function and improves symptoms in LAM patients, but the long-term benefit and toxicity are unknown, and some patients do not respond to therapy. LAM cells are metastatic but the primary tissue of origin is unknown. Unknown mechanisms underlying lung-specific metastasis, primary pathogenesis and female prevalence of LAM are obstacles to the development of new curative therapies. Our preliminary data from LAM lung single cell RNA sequencing (scRNAseq) analysis identified a unique population of cells (LAMCORE) expressing uterine- specific homeobox (HOX) transcription factors (TFs) that are not detected in normal lung; TF profiling of LAM patient-derived cells identified activation of Pre-B-cell leukemia homeobox 1 (PBX1), a cofactor of HOXs; comparative analysis of LAM lung scRNAseq and breast cancer cell PBX1-ChIPseq revealed overly represented LAMCORE signature genes with positive PBX1 binding peaks. Collectively, this strongly suggests a uterine origin of LAM cells and a central role of HOX/PBX1 signaling in LAM pathogenesis. The objective of this proposal is to identify mechanisms by which HOXs-associated gene networks regulate LAM pathogenesis and progression. Our central hypothesis is that HOX/PBX1 orchestrates a cell-specific gene network downstream of female hormones that regulates the survival and lung metastasis of LAMCORE cells. Three specific aims are proposed to delineate the molecular mechanisms through which HOX/PBX1 gene network contributes to LAM lesion metastasis, formation and progression. Aim 1: Determine pulmonary LAM-specific genomic and epigenomic responses and mechanisms underlying HOX/PBX1-mediated LAM pathogenesis. Aim 2: Determine the functional impacts of HOX/PBX1 network genes on metastatic potentials of LAM-derived cells in vitro and in vivo. Aim 3: Determine the effect of the HOX/PBX1 antagonist, HXR9, singly or in combination with Sirolimus, on estrogen-promoted lung metastasis potentials and lung remodeling in vivo. The completion of this proposal will provide for the first time: 1) a high-resolution integrative genomic/epigenomic blueprint of the LAMCORE cells, 2) a LAMCORE cell-specific HOX/PBX1 gene network with predicted key regulatory factors and targets within the network for follow-up perturbation and clinical diagnostic tests, 3) novel mechanistic insights into HOX/PBX1 regulatory circuits and their functional impact on LAM pathogenesis, and 4) preclinical proof-of-principle evidence for targeting HOX/PBX1-regulated female hormone-mediated LAM progression as a novel remission-inducing therapeutic strategy for LAM patients. Our work has major biomedical relevance for understanding LAM pathogenesis, developing new approaches for LAM diagnosis and designing alternative remission-inducing therapeutic strategies to maximize the benefit/toxicity ratio LAM treatment.