Control of lymphatic endothelial differentiation program

描述（由申请人提供）： 淋巴管系统对于维持体内液体平衡、免疫防御和摄取膳食脂肪至关重要。 淋巴管缺失或受损会导致肢体水肿，这是一种慢性和毁容性的四肢肿胀。 在癌症患者中，淋巴管是肿瘤细胞扩散的主要途径。 我们的长期目标是在分子水平上了解淋巴管生长的机制，确定淋巴管内皮分化程序中的关键分子，并利用这些知识在体外产生和分化淋巴管内皮细胞，以期潜在的临床应用，如治疗水肿。 为了解决淋巴管内皮细胞分化程序的调节，在淋巴管内皮细胞（LECs）中特异性表达的转录因子，如Prox-1和我们的初步研究中鉴定的其他八种新的转录因子，LECs或它们将在血管内皮细胞（BECs）中过表达，并使用DNA微阵列监测两种细胞类型的转录程序的变化。 为了在体内证实我们的结果，将产生在血管中表达诱导型Prox-1的转基因小鼠，并研究潜在的Prox-1靶基因的表达。 将研究在BEC和LEC中启动的转录程序，分别用血管生成和淋巴管生成的主要调节因子VEGF和VEGF-C以及对三种已知VEGF受体具有特异性的配体刺激。 为了了解来自不同器官的淋巴管内皮细胞之间的差异，将分离人肠和皮肤LEC，并鉴定在两种细胞群中差异表达的分子。 将使用体内/体外噬菌体肽和cDNA展示方法研究来自皮肤和肠道的LEC中细胞表面蛋白的组织特异性表达。 这些研究将为淋巴管内皮生长和分化的机制提供新的见解。 他们还应该确定区分浅表和内脏淋巴管的分子标记物，然后可以用于开发靶向药物输送到这些血管。

DESCRIPTION (provided by applicant): The lymphatic vasculature is essential for the maintenance of fluid balance in the body, for immune defense and for the uptake of dietary fat. Absent or damage lymphatic vessels lead to lymphedema, a chronic and disfiguring swelling of the extremities. In cancer patients the lymphatic vessels serve as a major route for the spread of tumor cells. Our long-term goal is to understand, at the molecular level, the mechanisms of lymphatic vessel growth, to identify the key molecules in the lymphatic endothelial differentiation program, and to use this knowledge to generate and differentiate lymphatic endothelial cells in vitro with a view to potential clinical applications, such as treatment of lymphedema. To address the regulation of the lymphatic endothelial differentiation program, transcription factors specifically expressed in the lymphatic endothelial cells (LECs), such as Prox-1 and eight other novel transcription factors identified in our preliminary studies, LECs or they will be overexpressed in blood vascular endothelial cells (BECs), and changes in the transcriptional programs of the two cell types will be monitored using DNA microarrays. To confirm our results in vivo, transgenic mice expressing inducible Prox-1 in blood vessels will be produced, and the expression of potential Prox-1 target genes will be studied. The transcriptional programs initiated in BECs and LECs upon stimulation with major regulators of angiogenesis and lymphangiogenesis, VEGF and VEGF-C, respectively, as well as with ligands specific for the three known VEGF receptors, will be studied. To understand the differences between lymphatic endothelial from different organs, human intestinal and skin LECs will be isolated, and molecules differentially expressed in the two cell populations will be identified. The tissue-specific expression of cell surface proteins in LECs from the skin and gut will be investigated using the in vivo/in vitro phage peptide and cDNA display approach. These studies will provide fundamental new insights into the mechanisms of lymphatic endothelial growth and differentiation. They should also identify molecular markers distinguishing superficial and visceral lymphatic vessels, which could then be used to develop targeted drug delivery to these vessels.