Developing a Rat Analogue of a Human Transglutaminase 2 Inhibitory Antibody to Facilitate Preclinical Testing in Treating Kidney Fibrosis

开发人转谷氨酰胺酶 2 抑制抗体的大鼠类似物，以促进治疗肾纤维化的临床前测试

• 批准号: MR/K00770X/1
• 负责人: Timothy Johnson
• 金额: $ 68.21万
• 依托单位: University of Sheffield
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2012
• 资助国家: 英国
• 起止时间: 2012 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=MR%2FK00770X%2F1
• 关键词: Developing; Rat; Analogue; Human; Transglutaminase

Fibrosis, or scarring, is a frequent feature of a number of relatively common, usually chronic, diseases. These include many types of lung, liver and heart disease and essentially all forms of chronic kidney disease. Studies of the mechanisms underlying the scarring process is an area of intense activity given that currently there is no recognized anti-scarring / anti-fibrotic therapy available for a condition that is ultimately fatal for millions of people each year. Subsequently the potential therapeutic benefits offered by the development of agents able to block or reduce the impact of scarring are considerable. Cumulative data from a range of different groups and experimental designs have highlighted tissue transglutaminase (transglutaminase type 2 ,TG2) as a key effector of the scarring process. Transglutaminases are a family of closely related enzymes that all catalyze the crosslinking of peptide chains via covalent epsilon (gamma-glutamyl) lysine bonds. It is this peptide crosslinking activity of TG2 that acts to produce the increased deposition and stabilization of extracellular matrix observed in chronic scarring. Knockdown of TG2, either genetically, or through the use of small molecule inhibitors, has been shown to have clear beneficial effects in animal models of chronic kidney disease (CKD). Scarring & fibrosis is reduced and kidney function preserved by up to 80% over the timescale of the experiments. Translation of these results into the patient setting would have profound therapeutic application in the area of CKD, and possibly other diseases that feature chronic scarring. Prolonging kidney function and delaying the requirement for dialysis or renal transplantation would offer a substantial increase in the quality of life of CKD patients and have major cost implications for the health service. Given the clear case for the development of TG2 inhibitors, there is much interest in this area of research. Development of inhibitors have been hampered by the degree of structural conservation between the 8 different members of the TG family. The catalytic site, or 'core', is highly conserved and all existing small molecule candidates have exhibited prohibitive levels of cross reactivity with other related enzymes. This is particularly important in the case of TG1 and TG3, which are critical to maintaining integrity of the dermis, and factor XIIIa, a major component of the clotting process. Inhibition of these related TG molecules produces serious side effects that would preclude a therapeutic role for existing small molecule inhibitors. A monoclonal antibody approach to this problem offers the potential to overcome these specificity issues due to the very precise nature of antibody targeting.Using an innovative immunization approach we have successfully generated a series of TG2-specific inhibitory monoclonal antibodies. All are specific for human TG2 and show no cross reactivity to other members of the enzyme family. We have established the inhibitory potential of these mAbs in different in vitro systems and derived IC50 data. The most effective of these antibodies has been humanised, with the affinity and inhibitory activity being preserved. The next stage in the development of this potential therapeutic is to generate preclinical data in FDA approved animal models of chronic fibrosis. The most effective monoclonal, AB1, and the other candidates, are all specific for human TG2, and lack significant inhibitory action against mouse or rat TG2. Accordingly, the aim of this project is to allow us to generate orthologous inhibitory antibodies against rat and mouse TG2, in order that we can gather this crucial preclinical data, attract downstream commercial partners, and accelerate the development of this potentially new class of therapeutic agents.

纤维化或瘢痕形成是许多相对常见的、通常是慢性的疾病的常见特征。这些疾病包括许多类型的肺、肝和心脏疾病以及基本上所有形式的慢性肾脏疾病。瘢痕形成过程的机制研究是一个非常活跃的领域，因为目前还没有公认的抗瘢痕形成/抗纤维化疗法可用于每年数百万人最终致命的疾病。因此，开发能够阻断或减少瘢痕形成影响的药物所提供的潜在治疗益处是相当可观的。来自一系列不同组和实验设计的累积数据突出了组织转氨酶（2型转氨酶，TG 2）作为瘢痕形成过程的关键效应物。转氨酶是一个密切相关的酶家族，它们都通过共价的γ-谷氨酰赖氨酸键催化肽链的交联。TG 2的这种肽交联活性起到产生在慢性瘢痕形成中观察到的细胞外基质的增加的沉积和稳定的作用。通过基因或使用小分子抑制剂敲低TG 2，已显示在慢性肾病（CKD）动物模型中具有明显的有益作用。在实验的时间范围内，疤痕和纤维化减少，肾功能保留高达80%。将这些结果转化到患者环境中将在CKD领域以及可能的以慢性瘢痕形成为特征的其他疾病中具有深远的治疗应用。延长肾功能和延迟透析或肾移植的需求将大幅提高CKD患者的生活质量，并对卫生服务产生重大成本影响。鉴于TG 2抑制剂开发的明确案例，人们对这一研究领域非常感兴趣。抑制剂的开发受到TG家族8个不同成员之间结构保守程度的阻碍。催化位点或“核心”是高度保守的，并且所有现有的小分子候选物都表现出与其他相关酶的禁止水平的交叉反应性。这在TG 1和TG 3的情况下尤其重要，TG 1和TG 3对维持真皮的完整性以及凝血过程的主要成分因子XIIIa至关重要。这些相关TG分子的抑制产生严重的副作用，这将妨碍现有小分子抑制剂的治疗作用。由于抗体靶向的非常精确的性质，针对该问题的单克隆抗体方法提供了克服这些特异性问题的潜力。使用创新的免疫方法，我们成功地产生了一系列TG 2特异性抑制性单克隆抗体。所有这些都对人TG 2具有特异性，并且与酶家族的其他成员没有交叉反应性。我们已经确定了这些mAb在不同体外系统中的抑制潜力，并得出了IC 50数据。这些抗体中最有效的已经被人源化，保留了亲和力和抑制活性。开发这种潜在治疗方法的下一个阶段是在FDA批准的慢性纤维化动物模型中生成临床前数据。最有效的单克隆抗体AB 1和其他候选物都对人TG 2具有特异性，并且对小鼠或大鼠TG 2缺乏显著的抑制作用。因此，该项目的目的是使我们能够产生针对大鼠和小鼠TG 2的正向抑制性抗体，以便我们能够收集这一关键的临床前数据，吸引下游商业合作伙伴，并加速这种潜在的新型治疗药物的开发。