O-GlcNAc-modified proteins leaked from dead cells suppress fibrosis

Tissue fibrosis is induced by chronic inflammation accompanied by repeated injuries. Chronic inflammation alters fibroblasts and stellate cells, maintaining the tissues in myofibroblasts and activating stellate cells. This activation promotes the augmentation of these cells and the abundant production of extracellular matrices, such as collagen. Fibrotic tissue dysfunction is eventually induced by expelling parenchymal cells with these abundant collagen depositions. To recover from tissue fibrosis, the activation of myofibroblasts and stellate cells is suppressed by selectively targeting these cells. Here we show that O-N-acetylglucosamine (GlcNAc)-modified proteins leaked from dead cells and GlcNAc-bearing polymers mimicking the GlcNAc moiety of these proteins suppress the activation of these cells; administration of the GlcNAc-bearing polymer into carbon tetrachloride-treated mice can improve liver fibrosis. We found that a multivalent GlcNAc moiety structure elicited antifibrotic activities in myofibroblasts by interacting with cell surface vimentin and desmin. Therefore, since these cells highly express cytoskeletal proteins, vimentin and desmin, on the cell surface and have GlcNAc-binding activity, we suggest that O-GlcNAc-modified proteins leaked from dead cells can function as suppressors of fibrosis and hyperplasia in spontaneous recovery. Moreover, we anticipate that GlcNAc-bearing polymers mimicked by O-GlcNAc-modified proteins will be useful as new therapeutic tools for fibrosis and hyperplasia. TGFb- stimulated NHDFs were control. The data showed comparison between TGFb- stimulated NHDFs and TGFb- stimulated NHDFs supplemented with AC-GlcNAc10 and comparison between TGFb- stimulated NHDFs and TGFb- stimulated NHDFs supplemented with cell debris from dead HeLa cells.