Analytical Chemistry and In-vivo Pharmacology Facility, Fondazione Istituto Italiano di Tecnologia, via Morego 30, 16163, Genova, Italy.
UOC Genetica Medica, IRCCS Istituto Giannina Gaslini, Via Gerolamo Gaslini 5, 16147, Genova, Italy.
Sci Rep. 2019 Jul 16;9(1):10310. doi: 10.1038/s41598-019-46639-1.
Deletion of phenylalanine 508 (F508del) in the cystic fibrosis transmembrane conductance regulator (CFTR) anion channel is the most frequent mutation causing cystic fibrosis (CF). F508del-CFTR is misfolded and prematurely degraded. Recently thymosin a-1 (Tα-1) was proposed as a single molecule-based therapy for CF, improving both F508del-CFTR maturation and function by restoring defective autophagy. However, three independent laboratories failed to reproduce these results. Lack of reproducibility has been ascribed by the authors of the original paper to the use of DMSO and to improper handling. Here, we address these potential issues by demonstrating that Tα-1 changes induced by DMSO are fully reversible and that Tα-1 peptides prepared from different stock solutions have equivalent biological activity. Considering the negative results here reported, six independent laboratories failed to demonstrate F508del-CFTR correction by Tα-1. This study also calls into question the autophagy modulator cysteamine, since no rescue of mutant CFTR function was detected following treatment with cysteamine, while deleterious effects were observed when bronchial epithelia were exposed to cysteamine plus the antioxidant food supplement EGCG. Although these studies do not exclude the possibility of beneficial immunomodulatory effects of thymosin α-1, they do not support its utility as a corrector of F508del-CFTR.
苯丙氨酸 508 缺失（F508del）在囊性纤维化跨膜电导调节因子（CFTR）阴离子通道中是导致囊性纤维化（CF）最常见的突变。F508del-CFTR 错误折叠并过早降解。最近，胸腺肽 α-1（Tα-1）被提议作为 CF 的单一分子治疗方法，通过恢复有缺陷的自噬来改善 F508del-CFTR 的成熟和功能。然而，三个独立的实验室未能重现这些结果。原始论文的作者将缺乏可重复性归因于 DMSO 的使用和不当处理。在这里，我们通过证明 DMSO 引起的 Tα-1 变化是完全可逆的，并且来自不同储备溶液的 Tα-1 肽具有等效的生物学活性，解决了这些潜在问题。考虑到这里报道的负面结果，六个独立的实验室未能证明 Tα-1 可纠正 F508del-CFTR。这项研究还质疑自噬调节剂半胱氨酸，因为在用半胱氨酸治疗后未检测到突变 CFTR 功能的恢复，而当用半胱氨酸加抗氧化食品补充剂 EGCG 暴露于支气管上皮时观察到有害影响。尽管这些研究不排除胸腺肽 α-1 具有有益的免疫调节作用的可能性，但它们不支持其作为 F508del-CFTR 校正物的用途。
