Optimization of the potency and specificity of engineered regulatory t cells to treat inflammatory and fibrotic liver diseases

慢性肝病是英国第五大最常见的死亡原因，其患病率正在急剧上升，主要是由于病毒性肝炎、与酒精有关的肝病和非酒精性脂肪肝的负担增加。英国日益加重的肝病负担与其他慢性疾病和大多数癌症在健康和预期寿命方面取得的巨大改善形成了鲜明对比。因此，迫切需要找到新的治疗方式来预防或阻止肝病的进展，肝病的发展有增无减，会导致门静脉高压症、癌症和最终死亡等并发症。尽管肝脏疾病进展的分子和细胞事件仍然知之甚少，但局部和全身炎症反应的失调参与了放大肝脏损伤和纤维化，从而导致临床代偿失调和死亡。在这方面，晚期肝病患者已被证明表现出多种先天和获得性免疫缺陷。正如之前在自身免疫性肝炎和原发性硬化性胆管炎中所报道的那样，这包括CD4+Foxp3+调节性T细胞(Tregs)的数量和功能的减少，Tregs是维持免疫耐受所必需的淋巴细胞亚群，具有迁移到炎症部位并发挥强大的抗炎、组织修复和再生特性的能力。在改善慢性炎症性疾病的免疫病理学和在自身免疫和移植中重建耐受性的前景下，基于Treg的细胞疗法的发展引起了越来越多的兴趣。这是尽管关于炎症微环境如何控制体内Treg的运输、激活、寿命、稳定性和抑制功能的知识存在严重差距。伦敦国王学院率先使用了体外扩展的Treg收养转移。我们在肾脏(一项和两项研究，Gamechanger)和肝移植(THRIL)中使用非工程自体多克隆Treg的临床试验已经证明了体外扩展的非工程多克隆Treg移植的安全性，并为其生物学效果提供了令人鼓舞的证据。然而，对Treg的贩运、效力和寿命的有限控制意味着，这一策略不太可能实现Treg免疫疗法作为一种真正变革性的细胞疗法的承诺。嵌合抗原受体(CARS)和功能获得基因工程为重新编程Treg提供了独特的机会，以解决上述限制。我们和其他人已经产生了针对人类HLA-A2的Car人类Tregs，并显示它们被运输到表达HLA-A2的器官，与多克隆Tregs相比，具有更好的抗炎作用。这些结果引起了人们对在人类中使用CAR-Tregs的浓厚兴趣，由我们的剥离公司Quell Treeutics赞助的一项临床试验目前正在进行中，该试验使用抗人类白细胞抗原A2 CAR-Tregs进行肝移植(Liberate，NCT05234190)。然而，抗HLA-A2 CAR-Tregs只能使接受了HLA-A2阳性肝移植的阴性移植受者受益。因此，有必要产生器官特异性CAR-Tregs，而不是同种异体抗原特异性CAR-Tregs来治疗非移植肝患者。我们现在提议创造一种人类下一代模块化CAR-Treg产品，专门设计用于治疗炎症性和纤维性肝病

The prevalence of chronic liver disease, the 5th most common cause of death in the UK is rising sharply mainly due to the increasing load of viral hepatitis, alcohol- related liver disease and non-alcoholic fatty liver. This increasing burden of liver disease in the UK is in stark contrast to the vast improvements made in health and life expectancy for other chronic disorders and most cancers. There is a pressing need therefore to find novel modalities of treatment to prevent or halt liver disease progression, which unabated leads to complications such as portal hypertension, cancer and ultimately death. Although the molecular and cellular events underlying the progression of liver disease remain poorly understood, dysregulated local and systemic inflammatory responses are involved in amplifying hepatic injury and fibrogenesis, which leads to clinical decompensation and death. In this regard, patients with advanced forms of liver disease have been shown to exhibit multiple innate and adaptive immune deficits. As previously reported in autoimmune hepatitis and primary sclerosing cholangitis, this includes reductions in the number and function of CD4+Foxp3+ regulatory T cells (Tregs), which are a lymphocyte subset that is essential for the maintenance of immunological tolerance and that has the capacity to migrate to sites of inflammation and exert powerful anti-inflammatory, tissue repair and regenerative properties. The prospect of ameliorating immunopathology in chronic inflammatory diseases and re-establishing tolerance in autoimmunity and transplantation, has prompted a growing interest in the development of Treg-based cell therapies. This is despite critical gaps in knowledge regarding how the inflammatory microenvironment controls Treg trafficking, activation, longevity, stability, and suppressive function in vivo. King's College London has pioneered the use of ex vivo expanded Treg adoptive transfer. Our clinical trials using non-engineered autologous polyclonal Tregs in kidney (ONE and TWO Studies, Gamechanger) and liver transplantation (THRIL) have demonstrated the safety of ex vivo expanded non-engineered polyclonal Treg transfer and provided encouraging evidence for their biological efficacy. However, the limited control over Treg trafficking, potency and longevity means that this strategy is unlikely to fulfil the promise of Treg immunotherapy as a truly transformative cell therapy. Chimeric antigen receptors (CARs) and gain-of-function genetic engineering provide unique opportunities to reprogram Tregs to address the limitations outlined above. We and others have generated HLA-A2-specific CAR human Tregs and shown their trafficking to organs expressing HLA-A2 with superior anti-inflammatory effects as compared to polyclonal Tregs. These results have generated considerable interest in the use of CAR-Tregs in humans, and a clinical trial sponsored by our spin-off company Quell Therapeutics employing anti-HLA-A2 CAR-Tregs in liver transplantation is currently underway (LIBERATE, NCT05234190). Anti-HLA-A2 CAR-Tregs, however, can only benefit HLA-A2-negative transplant recipients who have received an HLA-A2-positive liver. There is a need therefore to generate organ- rather than allo-antigen specific CAR-Tregs to treat non-transplant liver patients. We propose now to create a human next generation modular CAR-Treg product specifically designed to treat inflammatory and fibrotic liver diseases