LPL-Deficient Cats-A Quantitative Model of Gene Delivery

描述（由申请人提供）：定量数据对于设计有效的干细胞治疗方案至关重要。我们已经确定了一种新的动物模型，脂蛋白脂酶缺陷（LPL-/-）猫，它将提供这些重要的数据。脂蛋白脂肪酶是调节血浆脂蛋白分解和脂质代谢的关键酶。lpl缺乏症是一种严重的常染色体隐性遗传病，其特征是严重的乳糜小体血症、胰腺炎、爆发性黄瘤、视网膜脂血症、记忆丧失和发育不全。这种疾病在人类中被称为“家族性乳糜微粒血症”。LPL-/-猫有相同的突变，不能水解乳糜微粒，导致它们的血浆脂质谱（PLP）相同的畸变。该项目将确定表达活性LPL的异体间充质间质细胞（MSCs）是否会纠正这种遗传缺陷。初步研究表明，同种异体间充质干细胞可以合成LPL，并能暂时纠正LPL缺陷。最初，我们将量化在LPL-/-猫中增加和多次静脉注射LPL+/+ MSCs的效果（Aim I）。我们期望供体间充质干细胞能够植入宿主骨髓并分泌活性脂蛋白脂肪酶。一旦进入循环，LPL与内皮细胞上的特定位点结合，水解乳糜微粒并纠正这种代谢缺陷。减少循环乳糜微粒和甘油三酯很容易监测。还将研究影响移植的潜在因素，如各种给药途径、受体cat的放射预处理以及注射预分化的MSCs （Aim II）。由于易于测量治疗效果，lpl缺陷猫提供了一个极好的机会来证明异体间充质干细胞纠正这种遗传缺陷的能力。这种独特的模型可以直接定量分析治疗反应，同时测量近交动物种群中MSCs的存在。该项目将提供重要的剂量-反应和时间过程数据，确定注射MSCs的组织分布，并提供其他必要的细胞动力学数据。这一信息将直接转化为设计具有类似和其他代谢紊乱的人类患者的临床试验。

DESCRIPTION (provided by applicant): Quantitative data are essential for the design of effective stem cell treatment protocols. We have identified a novel animal model, the lipoprotein lipase-deficient (LPL-/-) cat, that will provide this essential data. Lipoprotein lipase is a key enzyme regulating plasma lipoprotein breakdown and lipid metabolism. LPL-deficiency is a serious autosomal recessive disorder characterized by severe chylomicronemia, pancreatitis, eruptive xanthomata, lipemia retinalis, memory loss and failure to thrive. This disease is termed "familial chylomicronemia" in humans. LPL-/- cats share the identical mutation and cannot hydrolyze chylomicrons resulting in identical aberrations of their plasma lipid profile (PLP). This project will determine if allogeneic mesenchymal stromal cells (MSCs) expressing active LPL will correct this genetic defect. Preliminary studies demonstrate that allogeneic MSCs synthesize LPL and transiently correct this LPL deficiency. Initially, we will quantify the effects of increasing and multiple intravenous doses of LPL+/+ MSCs in LPL-/- cats (Aim I). We anticipate that donor MSCs will engraft the host's bone marrow and secrete active lipoprotein lipase. Once in circulation, LPL binds to specific sites on endothelial cells, hydrolyzes chylomicrons and corrects this metabolic defect. Decreases in circulating chylomicrons and triglycerides are easily monitored. Potential factors affecting engraftment, such as various routes of administration, pre-treatment of the recipient cat with radiation, and injection of pre-differentiated MSCs will also be investigated (Aim II). Because of the ease of measuring therapeutic effects, LPL-deficient cats offer an excellent opportunity to demonstrate the ability of allogeneic MSCs to correct this genetic defect. This unique model allows direct quantitative analyses of therapeutic responses while simultaneously measuring the presence of MSCs in an outbred animal population. This project will provide important dose-response and time- course data, identify tissue distribution of injected MSCs, and supply other essential cytokinetic data. This information will directly translate to the design of clinical trials in human patients with similar and other metabolic disorders. PUBLIC HEALTH RELEVANCE: This project will investigate the potential of allogeneic bone marrow stem cells to correct heritable metabolic errors in an out-bred strain of cats. We will isolate adult bone marrow stem cells (MSCs) from cats with normal lipoprotein lipase activity and inject them into cats lacking lipoprotein lipase activity. In this project we will investigate several different methods for increasing this response and methods to enhance engraftment of these cells and prolong these therapeutic effects.