Safeguard mechanisms can ameliorate the potential risks associated with cell therapies but currently rely on the introduction of transgenes. This limits their application owing to immunogenicity or transgene silencing. We aimed to create a control mechanism for human cells that is not mediated by a transgene. Using genome editing methods, we disrupt uridine monophosphate synthetase (UMPS) in the pyrimidine de novo synthesis pathway in cell lines, pluripotent cells and primary human T cells. We show that this makes proliferation dependent on external uridine and enables us to control cell growth by modulating the uridine supply, both in vitro and in vivo after transplantation in xenograft models. Additionally, disrupting this pathway creates resistance to 5-fluoroorotic acid, which enables positive selection of UMPS-knockout cells. We envision that this approach will add an additional level of safety to cell therapies and therefore enable the development of approaches with higher risks, especially those that are intended for limited treatment durations.

保障机制可以改善与细胞疗法有关的潜在风险，但目前依赖转基因的引入。由于免疫原性或转基因沉默，这限制了它们的应用。我们旨在为人类细胞创造一种不受转基因介导的控制机制。使用基因组编辑方法，我们破坏了尿苷单磷酸合成酶（UMPS）在细胞系，多能细胞和原代人T细胞中从头合成嘧啶。我们表明，这使增殖依赖于外部尿苷，并使我们能够通过在体外和体内移植异种移植模型后调节尿苷供应来控制细胞生长。另外，破坏该途径产生了对5-氟乳清酸的抗性，这使得能够对UMPS敲除细胞进行阳性选择。我们设想，这种方法将为细胞疗法增加更高的安全性，从而使开发具有更高风险的方法成为可能，尤其是那些旨在限制治疗时间的方法。