miR-92a regulates TGF-ß1-induced WISP1 expression in pulmonary fibrosis.

Idiopathic pulmonary fibrosis (IPF) is the most common and fatal form of idiopathic interstitial pneumonia. MicroRNAs (miRNAs), short, single-stranded RNAs that regulate protein expression in a post-transcriptional manner, have recently been demonstrated to contribute to IPF pathogenesis. We have previously identified WNT1-inducible signaling pathway protein 1 (WISP1) as a highly expressed pro-fibrotic mediator in IPF, but the underlying mechanisms resulting in increased WISP1 expression, remain elusive. Here, we investigated whether WISP1 is a target of miRNA regulation. We applied a novel supervised machine learning approach, which predicted miR-30a/d and miR-92a target sites in regions of the human WISP1 3'UTR preferentially bound by the miRNA ribonucleoprotein complex. Both miRNAs were decreased in IPF samples, whereas WISP1 protein was increased. We demonstrated further that transforming growth factor (TGF)-ß1-induced WISP1 expression in primary lung fibroblasts in vitro and lung homogenates in vivo. Notably, miR-30a and miR-92a reversed TGF-ß1-induced WISP1 mRNA expression in lung fibroblasts. Moreover, miR-92a inhibition increased WISP1 protein expression in lung fibroblasts. An inverse relationship for WISP1 and miR-92a was found in a TGF-ß1 dependent lung fibrosis model in vivo. Finally, we found significantly increased WISP1 expression in primary IPF fibroblasts, which negatively correlated with miR-92a level ex vivo. Altogether, our findings indicate a regulatory role of miR-92a for WISP1 expression in pulmonary fibrosis.

WNT1 inducible signaling pathway protein 1 (WISP1): a novel mediator linking development and disease.

WISP1 is a secreted, matricellular protein allocated to the CCN protein family. The CCN protein family consists of six, modular structured, secreted proteins. WISP1 is mainly expressed during organ development and under diseased conditions, such as fibrosis or cancer. Its expression is associated with proliferation, cytoprotection, as well as extracellular matrix production, thereby representing a highly attractive therapeutical target for future applications.

Aptazyme-mediated regulation of 16S ribosomal RNA.

Developing artificial genetic switches in order to control gene expression via an external stimulus is an important aim in chemical and synthetic biology. Here, we expand the application range of RNA switches to the regulation of 16S rRNA function in Escherichia coli. For this purpose, we incorporated hammerhead ribozymes at several positions into orthogonalized 16S rRNA. We observed that ribosomal function is remarkably tolerant toward the incorporation of large additional RNA fragments at certain sites of the 16S rRNA. However, ribozyme-mediated cleavage results in severe reduction of 16S rRNA stability. We carried out an in vivo screen for the identification of sequences acting as ligand-responsive RNA switches, enabling thiamine-dependent switching of 16S rRNA function. In addition to expanding the regulatory toolbox, the presented artificial riboswitches should prove valuable to study aspects of rRNA folding and stability in bacteria.