Use of eukaryotic algae to deliver inexpensive human proteins for the treatment of Type 1 diabetes

该提案旨在开发一种强大的新表达系统，以生产和输送廉价和大量的人类治疗蛋白，用于治疗1型糖尿病。该表达体系是利用绿藻进行叶绿体转化的。叶绿体是在绿藻和植物细胞中发现的一种膜结合细胞器，用于进行光合作用。绿藻和高等植物的叶绿体DNA在每个细胞中都有许多拷贝，因此叶绿体转化有可能产生大量的外源蛋白质，这是由于转化DNA的高拷贝数扩增。目前还没有有效的治疗人类1型糖尿病的方法。传统的胰岛素替代可以改善血糖控制，但绝不是治愈。虽然胰岛移植可能是一种有效的治疗糖尿病的方法，但它的使用受到人类胰岛供应不足的限制。此外，胰岛移植患者仍然需要终生的亚胺抑制来防止移植物的排斥反应，这可能导致严重的副作用。通过口服给药诱导对可溶性蛋白的耐受性是治疗自身免疫性疾病（如1型糖尿病）的一种有吸引力的免疫疗法，但需要高剂量和重复的抗原，这可能非常困难和昂贵的生产。本项目的具体目标是利用衣藻叶绿体生产人胰岛蛋白谷氨酸脱羧酶（GAD）和胰岛素，以及治疗1型糖尿病的免疫调节分子白介素-4 （IL-4）。该项目的成功将导致开发出独特的、成本更低的、基于免疫的I型糖尿病治疗方法，与以前现有的治疗方案相比，其疗效更高，副作用更少。

This proposal aims to develop a powerful new expression system to produce and deliver inexpensive and high quantities of human therapeutic proteins for the treatment of Type 1 diabetes. The new expression system is based on the utilization of green algae by means of chloroplast transformation. The chloroplast is a membrane-bound organelle found in green algae and plant cells that conducts photosynthesis. There are many copies of chloroplast DNA per cell in both green algae and higher plants, and therefore chloroplast transformation has the potential to generate large amounts of foreign proteins due to the high copy number amplification of the transforming DNA.No effective therapy has been available for the treatment of type 1 diabetes in humans. Conventional insulin replacement can improve glycemic control, but is by no means a cure. While islet transplantation may be an effective treatment for diabetes, its use is limited by me short supply of human islets. Moreover, islet transplant patients still require life-long imiminosuppression to prevent rejection of the graft, which could lead to serious side effects. The induction of tolerance to a soluble protein by oral administration represents an attractive immune-based therapy for the treatment of autoimmune disease such as Type 1 diabetes, but requires the administration of high and repeated doses of antigen, which could be potentially very difficult and expensive to produce. The specific objectives of this project are to use Chlamydomonas chloroplast to produce the human islet protein glutamic acid decarboxylase (GAD) and insulin, as well as the immunoregulatory molecule interleukin-4 (IL-4) for therapy of Type 1 diabetes. The success of this project should lead to the development of unique, lower cost, immune-based therapies for Type I diabetes, with increased efficacy, and fewer side effects than previously existing treatment options.