Lung fibroblasts play major roles in the lung repair/fibrosis process through synthesis and remodeling of extracellular matrix. Those aberrant activations and elevated proliferations are associated with several fibrotic lung diseases, such as idiopathic pulmonary fibrosis (IPF). Targeting fibroblasts is a promising approach for preventing aberrant remodeling of lung architecture and protect irreversible pulmonary fibrosis. In this study, we developed an aptamer that can target lung fibroblasts and explored its potential as a delivery vehicle of cytotoxic agents intracellularly. The aptamer was discovered from artificial nucleic acid libraries through cell-based systematic evolution of ligands by exponential enrichment (cell-SELEX). This indole-modified aptamer can bind to LL97A cells, a fibroblast cell line derived from IPF patients, with high affinity (K_d = 70 nM). It also showed affinity to other lung fibroblasts, while cross-reactivity to epithelial cells was minimal. An aptamer-monomethyl auristatin F (MMAF) conjugate was generated by hybridizing with complementary DNA linked to MMAF. The resulting aptamer-MMAF conjugate inhibited proliferation of fibroblasts but appeared non-toxic to non-targeted epithelial cells. Our results show that artificial nucleic acid aptamer may potentially be used for fibroblast-specific therapy and diagnostic applications.

肺成纤维细胞通过细胞外基质的合成和重塑在肺修复/纤维化过程中起主要作用。那些异常的激活和增高的增殖与几种纤维化的肺部疾病有关，例如特发性肺纤维化（IPF）。靶向成纤维细胞是防止肺结构异常重塑和保护不可逆性肺纤维化的有前途的方法。在这项研究中，我们开发了可靶向肺成纤维细胞的适体，并探讨了其作为细胞内细胞毒剂传递载体的潜力。通过基于细胞的指数富集（cell-SELEX）配体的系统进化，从人工核酸文库中发现了适体。这种吲哚修饰的适体可与LL97A细胞结合，LL97A细胞是源自IPF患者的成纤维细胞系，K _d  = 70 nM）。它也显示出对其他肺成纤维细胞的亲和力，而与上皮细胞的交叉反应极少。通过与连接至MMAF的互补DNA杂交产生适体-单甲基耳他汀F（MMAF）缀合物。所得的适体-MMAF缀合物抑制成纤维细胞的增殖，但对非靶向的上皮细胞无毒。我们的结果表明，人工核酸适体可能会用于成纤维细胞特异性治疗和诊断应用。