Low-cost proinsulin-transferrin fusion protein in rice for treatment of diabetes

描述（由申请人提供）：糖尿病已成为世界范围内毁灭性的流行病。胰岛素因其控制血糖水平的能力而被广泛用作帮助控制糖尿病的治疗方法，并且在全世界范围内需求量很大，但它面临着多种挑战，包括不利的代谢副作用、体内药物寿命短和成本高。如今，数百万人继续遭受糖尿病及其相关疾病的折磨和死亡。因此，迫切需要开发新型、廉价的降血糖药来治疗和阻止这种使人衰弱的疾病的快速蔓延。最近发现，与胰岛素相比，重组胰岛素原-转铁蛋白（ProINS-Tf）融合蛋白有助于增强和持续体内降血糖功效。虽然这种融合蛋白作为一种新型肝特异性降血糖药具有巨大的前景，可以克服胰岛素的一些缺点，但由于在哺乳动物细胞系中生产其产量低且成本高，其治疗用途目前在经济上不可行。为了充分发挥 ProINS-Tf 的所有优点，同时降低其供应成本，Ventria Bioscience 及其在南加州大学的合作者正在利用各自的专业知识在大米中表达 ProINS-Tf 嵌合蛋白，然后评估其作为新型降血糖药物的生物活性。该拟议项目具有三个相关的具体目标。在目标 1 中，Ventria 将使用其专有的表达技术，用由 ProINS 与 Tf 融合组成的嵌合基因构建体转化水稻植物，并产生表达 ProINS-Tf 的转基因植物。在目标 2 中，Ventria 将进行表达筛选分析，以确定 ProINS-Tf 表达水平最高的转基因事件，然后进行蛋白质纯化。在目标 3 中，Ventria 在南加州大学的合作者将通过体外细胞培养测定来确认 ProINS-Tf 的生物活性。这些研究的目的是开发一种新型且负担得起的肝细胞前药来治疗糖尿病。这些研究意义重大，与 NIH 促进人类健康和降低医疗保健成本的使命相关。

DESCRIPTION (provided by applicant): Diabetes has become a devastating epidemic worldwide. Insulin is commonly used as a treatment to help manage diabetes because of its ability to control blood glucose levels, and is in high demand worldwide, but it faces multiple challenges including adverse metabolic side-effects, short in vivo pharmaceutical life, and high cost. Today, millions of people continue to suffer and die from diabetes and its related conditions. Therefore, there is an urgent need to develop novel, inexpensive hypoglycemic agents to treat and arrest the fast spreading of this debilitating disease. A recombinant proinsulin-transferrin (ProINS-Tf) fusion protein was recently found to facilitate an enhanced and sustained in vivo hypoglycemic efficacy compared to insulin. While this fusion protein holds great promise as a novel hepato-specific hypoglycemic agent that can overcome some of the disadvantages of insulin, its therapeutic use is currently economically unfeasible due to low yields and high costs associated with its production in mammalian cell lines. In an effort to capture all the benefits of ProINS-Tf while lowering its supply cost, Ventria Bioscience and its collaborators at the University of Southern California are building on their respective expertise t express a ProINS-Tf chimeric protein in rice, and then assess its biological activities related to its usage as a novel hypoglycemic agent. This proposed project has three related specific aims. In Aim 1, Ventria will use its proprietary expression technology to transform rice plants with a chimeric gene construct composed of ProINS fused to Tf and will produce transgenic plants expressing ProINS-Tf. In Aim 2, Ventria will perform expression screening analysis to identify the transgenic events with the highest level expression of ProINS-Tf followed by protein purification. In Aim 3, Ventria's collaborators at the University of Southern California will confim the biological activities of ProINS-Tf through in vitro cell culture assays. The aims of these studies are to develop a novel and affordable hepatocyte prodrug for the treatment of diabetes. These studies are significant and relevant to the mission of the NIH to promote human health and reduce health care costs.