Understanding the role of endothelial Zeb1 in lymphatic vessels

新血管的形成在癌症和心血管系统疾病中很重要。使用从人类血管中分离并在培养中生长的细胞，我们最近发现了一种蛋白质，可以转换这些细胞的新陈代谢，使它们能够成熟并停止生长。这种蛋白质已经被证明与发育和癌细胞有关，但以前在血管细胞中没有。我们在培养细胞中的实验预测，这种蛋白质将控制血管如何生长，以应对心血管疾病，我们正在研究这一点在小鼠模型中是如何重要的。然而，我们最近发现，同样的蛋白质在淋巴管(将液体和细胞从组织返回血液的血管)中也以同样的方式受到调节。过多的组织液会导致疼痛和虚弱的情况，如淋巴水肿，淋巴管是肿瘤细胞转移的主要途径，也参与肥胖期间的脂肪沉积。因此，了解淋巴管的正常功能，以及这种功能是如何被控制的是至关重要的。淋巴管(LV)是血管系统的重要组成部分，控制着间质液体平衡、炎症过程、脂质、蛋白质和免疫细胞在全身的运输。虽然在过去一百年左右的大部分时间里，淋巴系统的衰竭与淋巴水肿有关，但最近的研究表明，淋巴生长和功能是多种疾病的基础，涉及的过程包括1)增强免疫治疗的有效性，2)减少与缺血心脏组织血运重建不良相关的炎症3)神经变性4)转移扩散5)肾功能衰竭和6)代谢性疾病。对于任何血管，包括血液，为了对其环境做出反应，内皮细胞(ECs)从静止的表型转变为激活的表型。这是最近通过使用单细胞RNAseq而产生的，它提供了关于存在的不同EC表型的信息，但关于它们是如何形成的信息有限。因此，对不同EC行为的转录控制对于理解不同表型是如何产生的至关重要。我们已经确定了一种转录因子(称为ZEB1)，它在淋巴管生长过程中受到动态调节，它的正常信号会诱导一种‘静止’而不是‘激活’的表型。这项工作将扩展我们的体内和分子特征，以确定ZEB1信号在淋巴生长的正常发育和病理模型中的影响。因此，转录因子活性可能是不同LEC表型产生的信号通路之一。我们推测，ZEB1是第一个被发现的淋巴系统转录因子，在生长过程中控制LEC的表型异质性。所有上述数据表明，ZEB1的缺失将通过减少淋巴管EC的静止而使淋巴管内皮细胞准备就绪。我们将通过实现以下目标来验证这一假设：目标1：内皮特异性ZEB1 KOAim中淋巴管的特征2：ZEB1中病理性淋巴重构的特征iECKOAim 3：确定导致ZEB1下调的信号事件

The formation of new blood vessels is important in cancer and diseases of the cardiovascular system. Using cells isolated from human blood vessels and grown in culture, we recently discovered a protein that can switch the metabolism of these cells so that they can mature and stop growing. This protein has been shown to be involved in development and in cancer cells, but not previously in blood vessel cells. Our experiments in cultured cells predict that this protein would control how blood vessels grow in response to cardiovascular disease, and we are working on how this is important in mice models. However, we recently discovered that the same protein is regulated in the same way in lymphatic vessels (vessels that return fluid and cells from the tissue back into the bloodstream). Excess tissue fluid causes painful and debilitating conditions such as lymphedema, and lymphatic vessels are the primary route of tumour cell metastasis and also involved in fat deposition during obesity. Therefore, understanding how lymphatic vessels normally function, and how that function is controlled is of essential importance. Lymphatic vessels (LV) are an essential component of the vascular system that control interstitial fluid balance, inflammatory processes, lipid, protein and immune cell transport throughout the body. While for most of the last hundred years or so failure of the lymphatic system has been associated with lymphoedema, more recently it has demonstrated that lymphatic growth and function is a underpins multiple diverse disease involved processes including 1) enhancing efficacy of immunotherapy, 2) reducing inflammation associated with poor revascularisation of ischaemic cardiac tissue 3) neurodegeneration 4) metastatic spread 5) renal failure and 6) metabolic diseases to name a few. For any vessel, including blood, to respond to its environment the endothelial cells (ECs) change their phenotype from a quiescent, to an activated. This has been born out most recently through the use of single cell RNASeq, which provides information regarding the different EC phenotypes that exist, but limited information regarding how they are made. Transcriptional control of different EC behaviour is therefore of key importance to understand how the different phenotypes arise. We have identified a transcription factor (called Zeb1) that is dynamically regulated during lymphatic vessel growth, and its normal signature induces a 'quiescent' rather than 'activated' phenotype. This work will expand on our in vivo and molecular characterisation to determine the impact of Zeb1 signalling in normal development and pathological models of lymphatic growth. Therefore, transcription factor activity is likely to be one of the signalling pathways in which different LEC phenotypes could arise. We speculate that Zeb1 is, the first identified transcription factor for the lymphatic system that controls LEC phenotypic heterogeneity during growth All the above data suggests that loss of Zeb1 will prime the lymphatic endothelium by reducing lymphatic EC quiescence. We will test this hypothesis by achieving the following aims:Aim 1: Characterisation of lymphatic vessels in an endothelial specific ZEB1 KOAim 2: Characterisation of pathological lymphatic remodelling in Zeb1 iECKOAim 3: Determination of signalling events leading to Zeb1 downregulation