Transforming growth factor ß-inhibitor Repsox downregulates collagen expression of scleroderma dermal fibroblasts and prevents bleomycin-induced mice skin fibrosis.

Inhibition of transforming growth factor (TGF)-ß1 signalling may be one of the most reliable approaches to treat skin fibrosis of scleroderma. Although there have been many basic researches of TGF-ß blockade reagents, few of them were proved to have inhibitory effects on fibrosis both in vitro and in vivo. In this study, we randomly chose four commercially available low molecular weight compounds (Repsox, LY2109761, LY364947 and K02288) from TGF-ß1 inhibitor library, and compared their antifibrotic effects in vitro and in vivo. We demonstrated that Repsox has the most potent inhibitory effects on TGF-ß-induced expression of CTGF and collagen of cultured normal dermal fibroblasts in vitro and their constitutive overexpression of scleroderma fibroblast in vitro. In addition, Repsox could attenuate skin fibrosis by bleomycin in vivo, via the downregulation of CTGF or collagen. Our results may facilitate clinical trial of Repsox against fibrotic diseases in future.

Dysregulated interleukin-23 signalling contributes to the increased collagen production in scleroderma fibroblasts via balancing microRNA expression.

OBJECTIVES: The overexpression of IL-12 family cytokines is implicated in the pathogenesis of SSc, but their exact role is still unclear. The aim of this study was to investigate the regulation of extracellular matrix expression by IL-23 and its contribution to the phenotype of SSc. METHODS: The mRNA expression was determined by PCR array and real-time PCR. The expression levels of proteins were determined by immunoblotting and immunohistochemical staining. The effect of IL-23 on dermal fibrosis in vivo was examined in a mouse model of SSc induced by bleomycin injection. RESULTS: Among the IL-12 family members, IL-23 decreased expression of type I collagen protein in cultured normal dermal fibroblasts. We found that miR-4458 and miR-18a mediated the reduction of collagen expression by IL-23. On the contrary, IL-23 up-regulated type I collagen expression in SSc fibroblasts. The paradoxical effects of IL-23 in SSc fibroblasts were also mediated by the balance between miR-4458 and miR-18a expression. Moreover, we revealed that injection of IL-23 into the mouse skin accelerated skin fibrosis. CONCLUSION: This is the first study to report that the balance of two miRNAs is involved in the collagen dysregulation in SSc fibroblasts. Clarification of the regulatory mechanism of tissue fibrosis by IL-23 in SSc skin may lead to a better understanding of this disease and new therapeutic approaches.

The expression of miR-124 increases in aged skin to cause cell senescence and it decreases in squamous cell carcinoma.

Skin senescence is induced by various factors including intrinsic aging and extrinsic aging. The current study compared the expression of microRNAs in young facial skin and senescent facial skin, and this study identified skin aging-related microRNAs. According to the results from a microRNA PCR Array, miR-124 was the microRNA that increased the most in senescent skin compared to young skin. Real-time PCR with a greater number of samples indicated that the increase in miR-124 levels in senescent facial skin was statistically significant. In situ hybridization was performed, and results indicated that the signal for miR-124 was evident in keratinocytes of senescent skin but not in those of young skin. The morphology of cultured normal human epidermal keratinocytes (NHEKs) transfected with a miR-124 mimic changed to an enlarged and irregular shape. In addition, the number of NHEKs positive for senescence-associated ß-galactosidase (SA-ß-gal) increased significantly as a result of the overexpression of the miR-124 mimic. The expression of miR-124 increased in UVB-irradiated NHEKs compared to controls in a dose-dependent manner. Expression of miR-124 in A431, a human cutaneous squamous cell carcinoma (SCC) cell line, decreased significantly compared to that in NHEKs. Forced overexpression of miR-124 as a result of the transfection of a miR-124 mimic in A431 resulted in the significant suppression of the proportion of cancer cells. The current results indicated that miR-124 increases as a result of cell senescence and that it decreases during tumorigenesis. The effect of supplementation of miR-124 in an SCC cell line suggests that senescence induction therapy with microRNA may be a new therapeutic approach for treatment of SCC.

NUP160-SLC43A3 is a novel recurrent fusion oncogene in angiosarcoma.

Angiosarcoma is a malignant vascular tumor originating from endothelial cells of blood vessels or lymphatic vessels. The specific driver mutations in angiosarcoma remain unknown. In this study, we investigated this issue by transcriptome sequencing of patient-derived angiosarcoma cells (ISO-HAS), identifying a novel fusion gene NUP160-SLC43A3 found to be expressed in 9 of 25 human angiosarcoma specimens that were examined. In tumors harboring the fusion gene, the duration between the onset of symptoms and the first hospital visit was significantly shorter, suggesting more rapid tumor progression. Stable expression of the fusion gene in nontransformed human dermal microvascular endothelial cells elicited a gene-expression pattern mimicking ISO-HAS cells and increased cell proliferation, an effect traced in part to NUP160 truncation. Conversely, RNAi-mediated attenuation of NUP160 in ISO-HAS cells decreased cell number. Confirming the oncogenic effects of the fusion protein, subcutaneous implantation of NUP160-SLC43A3-expressing fibroblasts induced tumors resembling human angiosarcoma. Collectively, our findings advance knowledge concerning the genetic causes of angiosarcoma, with potential implications for new diagnostic and therapeutic approaches.