Venous Malformations (VM): A Murine Mdoel to Identify Therapies to Targer Aberrant Venous Development

描述（由申请人提供）：静脉畸形（VM）是一种慢性疾病，通常在出生时或儿童时期出现。VM是由变宽的、形状异常的静脉组成的病变。平滑肌细胞在许多区域都不存在。随着年龄的增长，病变往往会扩大，并可能突然扩大，导致畸形和/或血栓形成导致疼痛。没有靶向治疗，VM的治疗非常有限，仅包括硬化疗法和重建手术。治疗后，病变经常复发。生殖系或体细胞TIE 2突变与VM相关。TIE 2是一种内皮受体酪氨酸激酶，调节血管静止的维持和血管生成的促进。我们的假设是内皮细胞中的TIE 2突变由于血管周围细胞的不正确分化和/或募集而导致异常静脉发育。因此，我们建议使用在患者中发现的表达TIE 2突变的内皮细胞来重现小鼠中的VM表型。VM的小鼠模型从未报道过。我们的初步数据表明，表达TIE 2-L914 F突变受体的HUVEC，当皮下注射到小鼠体内时，会形成血管病变，这些病变往往会随着时间的推移而生长。组织学检查显示血管过度增宽。异常通道周围的血管周围细胞数量稀少，病变处血流缓慢，主要为非搏动性。作为对照，我们使用表达TIE 2-野生型（WT）的HUVEC，这些细胞在我们的模型中不能形成血管。注射正常EC与骨髓间充质祖细胞（bmMPC）组合导致规则尺寸的血管形成。与bmMPC组合注射的HUVEC TIE 2-L914 F形成具有扩大的管腔的血管，具有稀少的血管周围细胞，并且没有明显的bmMPC分化/成熟。HUVEC TIE 2-WT的行为与正常EC相似。因此，我们假设TIE 2突变抑制了血管周围细胞的分化，以及管腔大小的正确控制。我们的研究将侧重于：目的2-确定TIE 2突变在血管周围细胞分化、管腔大小控制和运动性中的作用，我们将在鼠VM模型和3D胶原体外模型中使用bmMPC、周细胞或SMC;目的3-进行临床前研究，以确定VM的新型靶向治疗，以使病理性血管系统正常化或诱导其消退，并避免疾病反弹。

DESCRIPTION (provided by applicant): Venous malformation (VM) is a chronic condition often seen at birth or during childhood. VMs are lesions composed by widened, abnormally shaped veins. Smooth muscle cells are absent in many areas. The lesion tends to enlarge with age and can suddenly expand causing deformity and/or pain as a result of clot formation. No targeted therapies are available, and treatments for VM are very limited, including only sclerotherapy and reconstructive surgery. After treatment, lesions often recur. Germline or somatic TIE2 mutations have been associated with VMs. TIE2 is an endothelial receptor tyrosine kinase that regulates both maintenance of vascular quiescence and promotion of angiogenesis. Our hypothesis is that TIE2 mutations in the endothelial cells cause aberrant venous development due to an incorrect differentiation and/or recruitment of perivascular cells. Therefore we propose to use endothelial cells expressing the TIE2 mutations found in patients to recapitulate the VM phenotype in mouse. A murine model of VM has never been reported. Our preliminary data demonstrate that HUVECs expressing TIE2-L914F mutated receptor, when injected subcutaneously in mouse, form vascular lesions that tend to grow over time. The histology reveals excessively widened blood-filled vessels. Perivascular cells around the abnormal channels are scarce in number, and blood flow in the lesion is slow and mainly non-pulsatile. As control we used HUVECs expressing TIE2-Wild Type (WT), these cells are incapable of forming blood vessels in our model. Injection of normal ECs in combination with bone marrow mesenchymal progenitor cells (bmMPC) results in formation of regular sized blood vessels. HUVECs TIE2-L914F injected in combination with bmMPC formed instead vessels with enlarged lumen, with scarce perivascular cells, and no evident differentiation/maturation of bmMPC. HUVECs TIE2-WT behaved similarly to normal ECs. We thereby hypothesize that the TIE2 mutation inhibits perivascular cells differentiation, and the correct control of the lumen siz. Our research will focus on: Aim 1- Establishing a VM-murine model that reflects the patient's disease, with the use of EC with mutated TIE2 receptor or cells isolated from patient VMs; Aim 2- Determine the effects of TIE2 mutations in the perivascular cell differentiation, control of lumen size, and motility we will use bmMPC, pericytes or SMCs, in the murine VM model and in 3D collagen in vitro model; Aim 3- Perform pre-clinical studies to identify a novel targeted treatment for VMs, in order to normalize or induce regression of the pathological vasculature and avoid a rebound of the disease.