Verma Amrisha, Xu Kang, Du Tao, Zhu Ping, Liang Zhibing, Liao Shengquan, Zhang Juantao, Raizada Mohan K, Grant Maria B, Li Qiuhong
Department of Ophthalmology, College of Medicine, University of Florida, Gainesville, FL 32610-0284, USA.
Department of Physiology & Functional Genomics, College of Medicine, University of Florida, Gainesville, FL 32610, USA.
Mol Ther Methods Clin Dev. 2019 Jul 10;14:161-170. doi: 10.1016/j.omtm.2019.06.007. eCollection 2019 Sep 13.
The angiotensin converting enzyme 2 (ACE2) catalyzes the degradation of Angiotensin II (Ang II) to generate Angiotensin-(1-7), which reduces inflammation and oxidative stress stimulated by Ang II. ACE2 has been shown to be protective in cardiovascular and metabolic diseases including diabetes and its complications. However, the challenge for its clinical application is large-scale production of high-quality ACE2 with sufficient target tissue bioavailability. We developed an expression and delivery system based on the use of probiotic species (LP) to serve as a live vector for oral delivery of human ACE2. We show that codon-optimized ACE2 can be efficiently expressed in LP. Mice treated with the recombinant LP expressing the secreted ACE2 in fusion with the non-toxic subunit B of cholera toxin, which acts as a carrier to facilitate transmucosal transport, showed increased ACE2 activities in serum and tissues. ACE2-LP administration reduced the number of acellular capillaries, blocked retinal ganglion cell loss, and decreased retinal inflammatory cytokine expression in two mouse models of diabetic retinopathy. These results provide proof of concept for feasibility of using engineered probiotic species as live vector for delivery of human ACE2 with enhanced tissue bioavailability for treating diabetic retinopathy, as well as other diabetic complications.
血管紧张素转换酶2（ACE2）催化血管紧张素II（Ang II）降解以生成血管紧张素-（1-7），后者可减轻由Ang II刺激引起的炎症和氧化应激。ACE2已被证明在包括糖尿病及其并发症在内的心血管和代谢疾病中具有保护作用。然而，其临床应用面临的挑战是大规模生产具有足够靶组织生物利用度的高质量ACE2。我们开发了一种基于益生菌（LP）的表达和递送系统，用作口服递送人ACE2的活载体。我们表明，密码子优化的ACE2可以在LP中有效表达。用表达与霍乱毒素无毒B亚基融合的分泌型ACE2的重组LP处理的小鼠，霍乱毒素B亚基作为促进跨粘膜运输的载体，其血清和组织中的ACE2活性增加。在两种糖尿病视网膜病变小鼠模型中，给予ACE2-LP可减少无细胞毛细血管数量，阻止视网膜神经节细胞丢失，并降低视网膜炎症细胞因子表达。这些结果为使用工程益生菌作为活载体递送人ACE2的可行性提供了概念验证，该载体具有增强的组织生物利用度，可用于治疗糖尿病视网膜病变以及其他糖尿病并发症。
