Microvesicle-mediated delivery of miR-1343: impact on markers of fibrosis

Stolzenburg, L. R.; Harris, A.

Cell Tissue Res. 2017 Oct 13; 371(2):325-338

Abstract

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-beta) 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-beta pathway, or the pathway as a whole. We previously identified miR-1343 as a potent repressor of TGF-beta signaling and fibrosis through the direct attenuation of both canonical TGF-beta 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-beta 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-beta 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-beta signaling and markers of fibrosis. These results highlight a role for miR-1343 in fine-tuning the TGF-beta pathway and suggest its use as a therapeutic in fibrotic disease.

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