Engineering novel designer biologics in plant cells for oral treatment of ulcerative colitis

项目概要/摘要 炎症性肠病（IBD），包括两种最常见的亚型：克罗恩病（CD）和 溃疡性结肠炎（UC）代表一组肠道疾病，其引起肠粘膜的长期炎症。 消化道目前的治疗策略，包括传统的抗炎药物和 靶向促炎细胞因子肿瘤坏死因子α（TNFα）的新生物药物， 治疗效果和全身给药引起的药物不良反应。结肠靶向口服 抗TNF α药物的递送对于IBD的治疗是高度期望的，因为它提高了药物的功效， 降低全身毒性。植物细胞培养已成为一种安全且具有成本效益的生物生产平台 用于治疗性蛋白质植物细胞的一个独特之处在于，它们不仅可以作为“生物工厂”， 而且是重组生物制剂的口服递送载体。最近的研究表明，植物细胞 主要由纤维素微纤维制成的壁可以作为用于口服递送 生物药物该项目旨在利用两种独特的翻译后修饰-“糖基化”- 磷脂酰肌醇（GPI）锚”和“植物特异性羟脯氨酸（Hyp）-O-糖基化”-战略上 在植物细胞中设计和改造新型抗TNF α生物分子，以开发一类新型口服生物药物 用于UC的治疗。设计的抗TNF α生物分子由三个功能结构域组成： 抗TNF α抗体的单链可变片段（scFv），一种专有的Hyp-O-糖基化模块 由“Ser-Pro”基序或（SP）n（n= 5 - 30）的串联重复序列和C-末端GPI锚组成。而 GPI锚将在植物细胞表面“展示”所表达的抗TNF α生物分子（但仍然 包封在细胞壁内），从而可能产生高局部浓度的生物制剂，即（SP）n 糖基化酶将稳定蛋白质，使其在生物生产和口服递送过程中免于降解。 同时，修饰在（SP）n糖基化酶上的带负电荷的聚糖将靶向抗TNF α， 带正电荷的蛋白质总是在发炎的上皮细胞中聚集。设计师反 将研究由不同大小的（SP）n糖模块组成的TNFα生物分子的蓄积 在烟草BY-2细胞中，生物活性和在模拟胃液中的稳定性，这将确定最佳的 设计生物分子。为了改善植物细胞口服制剂的药代动力学行为， 生物药物，策略将开发，以加强植物细胞壁基质填充在细胞壁 孔/通道与聚合物分子，如聚乙二醇（PEG），以增加其容量， 保护被包裹的蛋白质。最后，口服设计者的治疗效果 将在葡聚糖硫酸钠中评估抗TNF α生物制剂（最佳设计）缓解UC症状的作用 （DSS）诱导的结肠炎小鼠模型。抗TNF α生物制剂的免疫调节作用将在 通过组织病理学分析和炎性标志物测定来确定。拟议的研究将 可能开发一个新的平台，生产有效的口服生物药物，用于治疗UC和其他疾病。 结肠炎性疾病。

Project Summary/Abstract Inflammatory bowel disease (IBD), including the two most common subtypes: Crohn’s disease (CD) and ulcerative colitis (UC), represents a group of intestinal disorders that cause prolonged inflammation of the digestive tract. The current therapeutic strategies, including the conventional anti-inflammatory medications and the new biologic drugs targeting the pro-inflammatory cytokine tumor necrosis factor alpha (TNFα), have limited therapeutic efficacy and adverse drug reactions resulting from systemic administration. Colon-targeted oral delivery of anti-TNFα agents is highly desirable for the treatment of IBD, as it improves the drugs’ efficacy while reducing the systemic toxicity. Plant cell culture has emerged as a safe and cost-effective bioproduction platform for therapeutic proteins. A unique feature of the plant cells is that they could serve not only as the “bio-factory,” but also the oral delivery vehicle for recombinant biologics. Recent advances have demonstrated that plant cell walls, made primarily of cellulose microfibrils, can act as an excellent natural capsule for the oral delivery of biologic drugs. This project aims to leverage two unique posttranslational modifications – “glycosyl- phosphatidylinositol (GPI) anchor” and “plant-specific hydroxyproline (Hyp)-O-glycosylation” – to strategically design and engineer novel anti-TNFα biomolecules in plant cells to develop a new class of oral biologic drugs for the treatment of UC. The designer anti-TNFα biomolecules consist of three functional domains: a N-terminal single-chain fragment variable (scFv) of an anti-TNFα antibody, a proprietary Hyp-O-glycosylation module comprised of tandem repeats of the “Ser-Pro” motif, or (SP)n (n= 5 to 30), and a C-terminal GPI anchor. While the GPI anchor will “display” the expressed anti-TNFα biomolecules at the plant cell surface (but still encapsulated within the cell wall) to presumably create a high local concentration of the biologics, the (SP)n glycomodule will stabilize the protein from degradation during both the bioproduction and oral delivery processes. Meanwhile, the negatively charged glycans decorated on the (SP)n glycomodule will target the anti-TNFα biomolecules to the inflamed epithelium where positively charged proteins are always built up. Designer anti- TNFα biomolecules consisting of different sized (SP)n glycomodules will be investigated for their accumulation in tobacco BY-2 cells, biological activity, and stability in a simulated gastric fluid, which will determine an optimal design for the biomolecules. In order to improve the pharmacokinetic behavior of the plant cell produced oral biologic drugs, strategies will be developed to reinforce the plant cell wall matrices by filling in the cell wall pores/channels with polymeric molecules, such as polyethylene glycol (PEG), to increase their capacity for protecting the encapsulated proteins. Finally, the therapeutic effectiveness of the orally administrated designer anti-TNFα biologic (optimal design) in mitigating UC symptoms will be assessed in a dextran sulfate sodium (DSS)-induced colitis mouse model. The immune-modulatory effects of the anti-TNFα biologics will be determined by a histopathological analysis and assay of the inflammatory markers. The proposed research will potentially develop a new platform to produce effective oral biologic drugs for the treatment of UC and other inflammatory diseases in the colon.