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

描述(申请人提供)：糖尿病已成为世界范围内的毁灭性流行病。胰岛素因其控制血糖水平的能力而被广泛用于糖尿病的治疗，在全球范围内需求量很大，但它面临着包括不良代谢副作用、体内药物寿命短和成本高等多重挑战。今天，数以百万计的人继续遭受糖尿病及其相关疾病的痛苦和死亡。因此，迫切需要开发新的、廉价的降血糖药物来治疗和阻止这种令人衰弱的疾病的快速传播。最近发现一种重组胰岛素原-转铁蛋白(ProINS-TF)融合蛋白，与胰岛素相比，在体内可以促进增强和持续的降血糖效果。虽然这种融合蛋白作为一种新型的肝特异性降糖剂具有很大的前景，可以克服胰岛素的一些缺点，但由于其在哺乳动物细胞系中的低产率和高成本，其治疗应用目前在经济上是不可行的。为了在降低供应成本的同时获得ProINS-Tf的所有好处，南加州大学的Ventria Bioscience及其合作者正在利用他们各自的专业知识，在大米中表达ProINS-Tf嵌合蛋白，然后评估其作为一种新型降糖剂的生物活性。这个拟议的项目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将ProINS与Tf融合组成的嵌合基因构建转化水稻植株，并将产生表达ProINS-Tf的转基因植株。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，文特里亚在南加州大学的合作者将通过体外细胞培养试验确定ProINS-TF的生物学活性。这些研究的目的是开发一种新的、负担得起的肝细胞前药来治疗糖尿病。这些研究对美国国立卫生研究院促进人类健康和降低医疗成本的使命意义重大。

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.