National Engineering Research Center for Biomaterials, College of Biomedical Engineering, Sichuan University, Chengdu, Sichuan, China.
West China Hospital, Sichuan University, Chengdu, Sichuan, China.
Diabetes. 2023 Jun 1;72(6):703-714. doi: 10.2337/db22-0860.
Genetic modification of non-β-cells to produce insulin is a promising therapeutic strategy for type 1 diabetes; however, it is associated with issues, including biosafety and precise regulation of insulin supply. In this study, a glucose-activated single-strand insulin analog (SIA) switch (GAIS) was constructed to achieve repeatable pulse activation of SIA secretion in response to hyperglycemia. In the GAIS system, the conditional aggregation domain-furin cleavage sequence-SIA fusion protein was encoded by the intramuscularly delivered plasmid and temporarily kept in the endoplasmic reticulum (ER) because it binds to the GRP78 protein; then, upon hyperglycemia, the SIA was released and secreted into the blood. In vitro and in vivo experiments systematically demonstrated the effects of the GAIS system, including glucose-activated and repeatable SIA secretion, long-term precise blood glucose control, recovered HbA1c levels, improved glucose tolerance, and ameliorated oxidative stress. Additionally, this system offers sufficient biosafety, as evidenced by the assays of immunological and inflammatory safety, ER stress, and histological evaluation. Compared with the viral delivery/expression system, the ex vivo implantation of engineered cells, and the exogenous inducer system, the GAIS system combines the advantages of biosafety, effectiveness, persistence, precision, and convenience, providing therapeutic potential for the treatment of type 1 diabetes.
We undertook this study to establish a glucose-responsive single-strand insulin analog (SIA) self-supply system in vivo. We sought to determine whether the endoplasmic reticulum (ER) can serve as a safe and temporary repository to store designed fusion proteins and release SIAs under hyperglycemic conditions for efficient blood glucose regulation. The intramuscularly expressed plasmid-encoded conditional aggregation domain-furin cleavage sequence-SIA fusion protein can be temporarily stored in the ER, and the SIA can be released under the stimulation of hyperglycemia, resulting in efficient and long-term regulation of stable blood glucose in mice with type 1 diabetes (T1D). The glucose-activated SIA switch system provides applicable potential for T1D therapy, integrating regulation and monitoring of blood glucose levels.
将非β细胞基因改造以产生胰岛素是治疗 1 型糖尿病的一种有前途的治疗策略；然而，它与包括生物安全性和胰岛素供应的精确调节在内的问题相关。在这项研究中，构建了葡萄糖激活的单链胰岛素类似物（SIA）开关（GAIS），以实现对高血糖的 SIA 分泌的可重复脉冲激活。在 GAIS 系统中，条件聚集域-弗林裂解序列-SIA 融合蛋白由肌肉内递送的质粒编码，并由于与 GRP78 蛋白结合而暂时保留在内质网（ER）中；然后，在高血糖时，SIA 被释放并分泌到血液中。体外和体内实验系统地证明了 GAIS 系统的效果，包括葡萄糖激活和可重复的 SIA 分泌、长期精确的血糖控制、恢复的 HbA1c 水平、改善的葡萄糖耐量和氧化应激的改善。此外，该系统具有足够的生物安全性，免疫和炎症安全性、ER 应激和组织学评估的检测结果证实了这一点。与病毒递送/表达系统、工程细胞的体外植入和外源性诱导剂系统相比，GAIS 系统结合了生物安全性、有效性、持久性、精确性和便利性的优点，为 1 型糖尿病的治疗提供了治疗潜力。
我们进行了这项研究，以在体内建立葡萄糖响应的单链胰岛素类似物（SIA）自供系统。我们试图确定内质网（ER）是否可以作为安全且临时的储存库，以在高血糖条件下储存设计的融合蛋白并释放 SIA，以有效调节血糖。肌肉内表达的质粒编码的条件聚集域-弗林裂解序列-SIA 融合蛋白可以暂时储存在 ER 中，并且可以在高血糖的刺激下释放 SIA，从而在 1 型糖尿病（T1D）小鼠中有效且长期调节稳定的血糖。葡萄糖激活的 SIA 开关系统为 T1D 治疗提供了应用潜力，整合了血糖水平的调节和监测。
