Uterine-specific genetic modification and lymphangioleiomyomatosis

描述（由申请方提供）：淋巴管平滑肌瘤病（LAM）是一种罕见疾病，主要见于女性，其特征为肺实质中非典型平滑肌细胞病变的弥漫性间质浸润，导致气道受限。该病的病因尚不清楚，但被认为与激素调节有关，因为它通常出现在月经初潮和绝经之间。此外，LAM通常在结节性硬化症（TSC）突变的患者中发现，这表明TSC的失活可能有助于其发展。我们正在研究子宫发育和相关的病理条件下删除和/或激活候选基因的途径，正常分化和功能的关键。我们通过组成性激活<$-catenin或通过表达结肠腺瘤性息肉病（APC）的截短等位基因，产生了子宫特异性平滑肌瘤（肌瘤）小鼠，我们已经显示了平滑肌瘤发展是血管扩张和随后的增生性瘢痕的结果的初步证据。苗勒管衍生的内部女性生殖道器官（子宫，输卵管，子宫颈和阴道的颅侧部分）是唯一的结构，从双能哺乳动物胚胎中没有发现在男性，这表明子宫的间充质基质细胞的生殖反应可能是肺纤维化的细胞的来源，并占LAM的女性特异性。我们假设肺LAM可能是由子宫血管病变引起的，子宫血管病变允许子宫基质细胞内渗，随后可以在肺中驻留和增殖。来自我们的具有子宫肥大和平滑肌瘤的小鼠模型的肺的组织学分析显示纤维化肺斑块类似于在人LAM中观察到的纤维化肺斑块，其也是HMB 45、aSMA和结蛋白阳性的，人LAM的标志物。我们建议进一步研究这一假设，具体目的如下：（1）证实肺部病变中的细胞来源于子宫，（2）确定外周血中是否可以检测到子宫间充质细胞，（3）测试肺部病变中平滑肌细胞的激素反应性，以及（4）评估肺部病变的标志物谱，以与人LAM进行比较。这些研究的结果将为继续研究LAM病变发展中涉及的触发因素和信号通路奠定基础，并为靶向这些通路的治疗药物的临床前研究提供体内模型系统。 公共卫生相关性：淋巴管平滑肌瘤病（LAM）研究中的一个主要未知数是浸润肺以形成纤维化病变的平滑肌细胞的起源细胞或组织。我们已经产生了子宫内伤口愈合缺陷的小鼠，这导致了子宫内膜增生、增生性瘢痕和纤维瘤。我们对肺部的初步研究结果表明，循环的创伤后子宫细胞可能是导致LAM的细胞。拟议的研究将调查子宫细胞是否是LAM中发现的纤维化细胞的来源，LAM肺部病变是否具有免疫反应，以及这些突变小鼠是否将成为研究纤维化细胞浸润肺部所涉及的机制和途径以及可能的治疗干预的临床前研究所需的模型系统。

DESCRIPTION (provided by applicant): Lymphangioleiomyomatosis (LAM) is a rare disease primarily found in females and is characterized by a diffuse interstitial infiltrate of atypical smooth muscle cell lesions in the lung parenchyma resulting in airway restriction. The etiology of the disease is unknown but is thought to involve hormonal regulation because it usually presents between menarche and menopause. Additionally, LAM is often found in patients with mutations in tuberous sclerosis complex (TSC), suggesting that inactivation of TSC can contribute to its development. We are studying uterine development and associated pathologies by conditionally deleting and/or activating candidate genes in pathways critical for normal differentiation and function. We have created mice with uterine-specific leiomyomas (fibroids) by either constitutively activating ¿-catenin or by expressing a truncated allele of adenomatous polyposis coli (APC) and we have shown preliminary evidence that the leiomyomas develop as a result of vascular hemorrhaging and subsequent hypertrophic scarring. The Mullerian duct-derived internal female reproductive tract organs (uterus, oviduct, cervix, and cranial portion of the vagina) are the only structures from the bipotential mammalian embryo not found in males, suggesting that the hormonally responsive mesenchymal stromal cells of the uterus might be the source of the cells for pulmonary fibrosis and account for the female-specificity of LAM. We hypothesized that pulmonary LAM might be caused by uterine vascular pathologies that allow intravasation of uterine stromal cells that can subsequently lodge and proliferate in the lungs. Histological analysis of the lungs from our mouse models with uterine hemorrhaging and leiomyomas showed fibrotic lung plaques similar to that observed in human LAM that were also HMB45-, aSMA- and desmin-positive, markers for human LAM. We propose to investigate this hypothesis further with the following Specific Aims: (1) confirm that cells in the lung lesions are derived from the uterus, (2) determine whether uterine mesenchymal cells can be detected in peripheral blood, (3) test the hormone responsiveness of the smooth muscle cells in the lung lesions, and (4) assess the marker profile of lung lesions for comparison with human LAM. The results from these studies will lay the foundation for continued investigation of the triggers and signaling pathways involved in the development of the LAM lesions as well as provide an in vivo model system for preclinical studies of therapeutics targeting those pathways. PUBLIC HEALTH RELEVANCE: One of the major unknowns in lymphangioleiomyomatosis (LAM) research is the cell or tissue of origin for the smooth muscle cells that infiltrate the lung to form the fibrotic lesions. We have generated mice with defective wound healing in uteri, which results in hemorrhaging, hypertrophic scarring and fibroids. Our preliminary results investigating the lungs suggest that circulating post-traumatic uterine cells might be the cells that cause LAM. The proposed studies will investigate whether the uterine cells are the source of fibrotic cells found in LAM, whether the LAM lung lesions are hormonally responsive, and whether these mutant mice will be a needed model system for investing the mechanisms and pathways involved in the infiltration of the lungs with fibrotic cells and for preclinical studies of possible therapeutic intervention.