Human Molecular Genetics Program, Lurie Children's Research Center, Chicago, IL, 60614, USA.
Department of Pediatrics, Northwestern University Feinberg School of Medicine, Chicago, IL, 60611, USA.
Cell Tissue Res. 2018 Feb;371(2):325-338. doi: 10.1007/s00441-017-2697-6. Epub 2017 Oct 11.
Tissue fibrosis, the development of fibrous connective tissue as a result of injury or damage, is associated with many common diseases and cannot be treated effectively. The complex biological processes accompanying fibrosis often involve aberrant signaling through the transforming growth factor beta (TGF-β) pathway. In the search for mechanisms to repress this signaling, microRNAs have emerged as a novel class of molecules capable of targeting single members of the TGF-β pathway, or the pathway as a whole. We previously identified miR-1343 as a potent repressor of TGF-β signaling and fibrosis through the direct attenuation of both canonical TGF-β receptors. Here, we build upon our previous findings to better characterize the function of endogenous miR-1343 in normal biology and examine the potential role of exogenous miR-1343 as a repressor of TGF-β signaling. CRISPR/Cas9-mediated deletion of miR-1343 from A549 lung epithelial cells impacts several processes and genes implicated in fibrosis and known to be TGF-β pathway effectors. Moreover, the responses are opposite to those we observed previously when miR-1343 was overexpressed in the same cell type. We also show that miR-1343 can be shuttled into exosomes, a type of extracellular vesicle that are exported by cells into the surrounding medium and can be absorbed by distant target cells. miR-1343 delivered into primary lung fibroblasts by exosomes has a measurable function in reducing TGF-β signaling and markers of fibrosis. These results highlight a role for miR-1343 in fine-tuning the TGF-β pathway and suggest its use as a therapeutic in fibrotic disease.
组织纤维化是一种由于损伤或损害导致纤维结缔组织发育的疾病，与许多常见疾病有关，且目前还无法有效治疗。纤维化伴随的复杂生物学过程通常涉及转化生长因子-β（TGF-β）途径的异常信号传导。在寻找抑制这种信号传导的机制时，miRNA 作为一类能够靶向 TGF-β 途径单个成员或整个途径的新型分子而出现。我们之前通过直接衰减两个经典 TGF-β 受体，鉴定出 miR-1343 是一种有效的 TGF-β 信号和纤维化抑制剂。在此，我们在之前的研究基础上，进一步研究内源性 miR-1343 在正常生物学中的功能，并探讨外源性 miR-1343 作为 TGF-β 信号抑制剂的潜在作用。CRISPR/Cas9 介导的 miR-1343 在 A549 肺上皮细胞中的缺失，影响了几个纤维化过程和基因，这些基因已知是 TGF-β 途径的效应物。此外，这些反应与我们之前在同一细胞类型中过表达 miR-1343 时观察到的反应相反。我们还表明，miR-1343 可以被转运到外泌体中，外泌体是一种细胞分泌到周围介质中的细胞外囊泡，并且可以被远处的靶细胞吸收。外泌体将 miR-1343 递送到原代肺成纤维细胞中，可以在降低 TGF-β 信号和纤维化标志物方面发挥可测量的功能。这些结果强调了 miR-1343 在微调 TGF-β 途径中的作用，并表明其在纤维化疾病中的治疗用途。
