The vast majority of people with cystic fibrosis (CF) are now eligible for CF transmembrane regulator (CFTR) modulator therapy. The remaining individuals with CF harbor premature termination codons (PTCs) or rare CFTR variants with limited treatment options. Although the clinical modulator response can be reliably predicted using primary airway epithelial cells, primary cells carrying rare CFTR variants are scarce. To overcome this obstacle, cell lines can be created by overexpression of mouse Bmi-1 and human TERT (hTERT). Using this approach, we developed 2 non-CF and 6 CF airway epithelial cell lines, 3 of which were homozygous for the W1282X PTC variant. The Bmi-1/hTERT cell lines recapitulated primary cell morphology and ion transport function. The 2 F508del-CFTR cell lines responded robustly to CFTR modulators, which was mirrored in the parent primary cells and in the cell donors’ clinical response. Cereblon E3 ligase modulators targeting eukaryotic release factor 3a (eRF3a) rescued W1282X-CFTR function to approximately 20% of WT levels and, when paired with G418, rescued G542X-CFTR function to approximately 50% of WT levels. Intriguingly, eRF3a degraders also diminished epithelial sodium channel (ENaC) function. These studies demonstrate that Bmi-1/hTERT cell lines faithfully mirrored primary cell responses to CFTR modulators and illustrate a therapeutic approach to rescue CFTR nonsense mutations.

中文翻译：

---

小分子 eRF3a 降解剂通过促进提前终止密码子通读来挽救 CFTR 无义突变

绝大多数囊性纤维化 (CF) 患者现在有资格接受 CF 跨膜调节剂 (CFTR) 调节剂治疗。其余患有 CF 的个体具有提前终止密码子 (PTC) 或罕见的CFTR变体，治疗选择有限。尽管使用初级气道上皮细胞可以可靠地预测临床调节剂反应，但携带罕见CFTR变体的初级细胞很少。为了克服这个障碍，可以通过小鼠 Bmi-1 和人类 TERT (hTERT) 的过表达来创建细胞系。使用这种方法，我们开发了 2 个非 CF 和 6 个 CF 气道上皮细胞系，其中 3 个是W1282X PTC 变体的纯合子。Bmi-1/hTERT 细胞系概括了原代细胞形态和离子转运功能。2F508del-CFTR细胞系对 CFTR 调节剂有强烈反应，这反映在亲代原代细胞和细胞供体的临床反应中。靶向真核细胞释放因子 3a (eRF3a) 的 Cereblon E3 连接酶调节剂将W1282X-CFTR功能恢复到大约 20% 的 WT 水平，当与 G418 配对时，将G542X-CFTR功能恢复到大约 50% 的 WT 水平。有趣的是，eRF3a 降解剂还降低了上皮钠通道 (ENaC) 的功能。这些研究表明，Bmi-1/hTERT 细胞系忠实地反映了原代细胞对 CFTR 调节剂的反应，并说明了一种挽救CFTR无义突变的治疗方法。