ABSTRACT
Arctiin, a lignin isolated from Arctium lappa, exhibits a variety of biological effects, including antiviral, antiinflammatory, and antiproliferative actions, in mammalian cells. In a previous study, arctiin was demonstrated to induce procollagen type I synthesis and exhibited protective effects against ultraviolet B (UVB) radiation in normal human dermal fibroblasts (nHDFs). However, the underlying molecular mechanism of arctiinmediated collagen synthesis remains unknown. In the present study, the mechanism for increased expression of collagen type 1α 1 chain (COL1A1) mRNA in arctiininduced nHDFs was identified. The expression of microRNA378b (miR378b), downregulated by arctiin, was correlated with the expression of sirtuin6 (SIRT6) mRNA, a regulator of COL1A1 mRNA. Furthermore, it was revealed that arctiin protected the UVB radiationmediated decrease in COL1A1 mRNA expression, through the miR378b/SIRT6 signaling pathway. In conclusion, these results suggest that arctiin regulates COL1A1 through the miR378bSIRT6 axis.
Subject(s)
Collagen Type I/metabolism , Fibroblasts/drug effects , Fibroblasts/metabolism , Furans/pharmacology , Gene Expression Regulation/drug effects , Glucosides/pharmacology , MicroRNAs/genetics , RNA, Messenger/genetics , Sirtuins/genetics , Cell Survival , Cells, Cultured , Collagen Type I, alpha 1 Chain , Dermis/cytology , Gene Expression Regulation/radiation effects , Humans , Plant Extracts/pharmacology , RNA Interference , Ultraviolet RaysABSTRACT
Ultraviolet (UV) light mediates skin aging and induces destruction of the dermis by modulating the expression levels of extracellular matrixassociated genes, including collagen and matrix metalloproteinases. Sirtuin 6 (SIRT6), a member of the sirtuin family of proteins, regulates collagen metabolism and is an established antiaging protein. However, the exact underlying mechanism by which SIRT6 expression is regulated in dermal fibroblasts during the aging process is unclear. The present study demonstrated that expression of microRNA378b (miR378b) is induced in UVBexposed human dermal fibroblasts (HDFs), and this was inversely associated with the mRNA expression levels of α1type 1 collagen (COL1A1). In addition, knockdown of miR378b enhanced the mRNA expression levels of COL1A1 in HDFs. A target analysis for miR378b was performed, and the results revealed that SIRT6, a regulator of COL1A1, contains a target sequence for miR378b in its 3'untranslated region. Notably, the present study demonstrated that an miR378b mimic and inhibitor may directly regulate SIRT6 expression in HDFs. In conclusion, the present study suggested that miR378b represses the mRNA expression levels of COL1A1 via interference with SIRT6 in HDFs, and may contribute to the underlying molecular mechanism by which UVB inhibits collagen I in dermal fibroblasts.
Subject(s)
Collagen Type I/genetics , Gene Expression Regulation/radiation effects , MicroRNAs/metabolism , RNA Interference , Sirtuins/metabolism , 3' Untranslated Regions/genetics , Collagen Type I/metabolism , Collagen Type I, alpha 1 Chain , Dermis/cytology , Down-Regulation/radiation effects , Fibroblasts/metabolism , Fibroblasts/radiation effects , Humans , MicroRNAs/genetics , Protein Binding/radiation effects , RNA, Messenger/genetics , RNA, Messenger/metabolism , Sirtuins/genetics , Ultraviolet RaysABSTRACT
We describe a rare conjoined twinning at 9 weeks of gestation. We compared the results of two- and three-dimensional sonography with autopsy findings after the termination of pregnancy. These results showed a thoracoomphalopagus with a shared heart and visceral organs. Three-dimensional sonography showed anencephaly in one of the embryos. Early and accurate prenatal diagnosis of this type of conjoined twins using three-dimensional sonography is critical for both parental counseling and minimizing maternal morbidity.
