title: Silibinin inhibits ICAM-1 expression via regulation of N-linked and O-linked glycosylation in ARPE-19 cells.
abstract: To evaluate the effects of silibinin on intercellular adhesion molecule-1 (ICAM-1) expression, we used ARPE-19 cells as a model in which tumor necrosis factor (TNF-α) and interferon (IFN-γ) enhanced ICAM-1 expression. This upregulation was inhibited by silibinin. In an adherence assay using ARPE-19 and THP-1 cells, silibinin inhibited the cell adhesion function of ICAM-1. The inhibitory effects of silibinin on ICAM-1 expression were mediated via the blockage of nuclear translocation of p65 proteins in TNF-α and phosphorylation of STAT1 in IFN-γ-stimulated cells. In addition, silibinin altered the degree of N-linked glycosylation posttranslationally in ARPE-19 cells by significantly enhancing MGAT3 gene expression. Silibinin can increase the O-GlcNAc levels of glycoproteins in ARPE-19 cells. In a reporter gene assay, PUGNAc, which can also increase O-GlcNAc levels, inhibited NF-κB reporter activity in TNF-α-induced ARPE-19 cells and this process was augmented by silibinin treatment. Overexpression of OGT gene was associated with reduced TNF-α-induced ICAM-1 levels, which is consistent with that induced by silibinin treatment. Taken together, silibinin inhibits ICAM-1 expression and its function through altered O-linked glycosylation in NF-κB and STAT1 signaling pathways and decreases the N-linked glycosylation of ICAM-1 transmembrane protein in proinflammatory cytokine-stimulated ARPE-19 cells.
authors.affiliation: Graduate Institute of Medical Science, National Defense Medical Center, No. 161, Section 6, Minquan East Road, Taipei 114, Taiwan ; Department of Ophthalmology, Tri-Service General Hospital, National Defense Medical Center, No. 325, Section 2, Cheng-Kong Road, Taipei 114, Taiwan.
authors.forename: Yi-Hao
authors.initials: YH
authors.lastname: Chen
authors.affiliation: Graduate Institute of Medical Science, National Defense Medical Center, No. 161, Section 6, Minquan East Road, Taipei 114, Taiwan ; Department of Ophthalmology, Tri-Service General Hospital, National Defense Medical Center, No. 325, Section 2, Cheng-Kong Road, Taipei 114, Taiwan.
authors.forename: Ching-Long
authors.initials: CL
authors.lastname: Chen
authors.affiliation: Graduate Institute of Medical Science, National Defense Medical Center, No. 161, Section 6, Minquan East Road, Taipei 114, Taiwan ; Department of Ophthalmology, Tri-Service General Hospital, National Defense Medical Center, No. 325, Section 2, Cheng-Kong Road, Taipei 114, Taiwan ; Graduate Institute of Aerospace and Undersea Medicine, National Defense Medical Center, No. 161, Section 6, Minquan East Road, Taipei 114, Taiwan.
authors.forename: Chang-Min
authors.initials: CM
authors.lastname: Liang
authors.affiliation: Department of Ophthalmology, Tri-Service General Hospital, National Defense Medical Center, No. 325, Section 2, Cheng-Kong Road, Taipei 114, Taiwan.
authors.forename: Jy-Been
authors.initials: JB
authors.lastname: Liang
authors.affiliation: Graduate Institute of Medical Science, National Defense Medical Center, No. 161, Section 6, Minquan East Road, Taipei 114, Taiwan ; Department of Ophthalmology, Tri-Service General Hospital, National Defense Medical Center, No. 325, Section 2, Cheng-Kong Road, Taipei 114, Taiwan.
authors.forename: Ming-Cheng
authors.initials: MC
authors.lastname: Tai
authors.affiliation: Department of Ophthalmology, Tri-Service General Hospital, National Defense Medical Center, No. 325, Section 2, Cheng-Kong Road, Taipei 114, Taiwan.
authors.forename: Yun-Hsiang
authors.initials: YH
authors.lastname: Chang
authors.affiliation: Graduate Institute of Medical Science, National Defense Medical Center, No. 161, Section 6, Minquan East Road, Taipei 114, Taiwan ; Department of Ophthalmology, Tri-Service General Hospital, National Defense Medical Center, No. 325, Section 2, Cheng-Kong Road, Taipei 114, Taiwan.
authors.forename: Da-Wen
authors.initials: DW
authors.lastname: Lu
authors.affiliation: Graduate Institute of Medical Science, National Defense Medical Center, No. 161, Section 6, Minquan East Road, Taipei 114, Taiwan ; Department of Ophthalmology, Tri-Service General Hospital, National Defense Medical Center, No. 325, Section 2, Cheng-Kong Road, Taipei 114, Taiwan ; Graduate Institute of Aerospace and Undersea Medicine, National Defense Medical Center, No. 161, Section 6, Minquan East Road, Taipei 114, Taiwan.
authors.forename: Jiann-Torng
authors.initials: JT
authors.lastname: Chen
mesh_terms: D000975:Antioxidants / Q000494:pharmacology*; D002448:Cell Adhesion / Q000187:drug effects; D002460:Cell Line; D005786:Gene Expression Regulation / Q000187:drug effects*; D006031:Glycosylation / Q000187:drug effects; D006801:Humans; D018799:Intercellular Adhesion Molecule-1 / Q000096:biosynthesis* / Q000235:genetics; D017351:N-Acetylglucosaminyltransferases / Q000096:biosynthesis; D016328:NF-kappa B / Q000378:metabolism; D050794:STAT1 Transcription Factor / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects*; D000077385:Silybin; D012838:Silymarin / Q000494:pharmacology*; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism
chemical_list: D000975:Antioxidants; C573420:ICAM1 protein, human; D016328:NF-kappa B; D050794:STAT1 Transcription Factor; C494079:STAT1 protein, human; D012838:Silymarin; D014409:Tumor Necrosis Factor-alpha; D018799:Intercellular Adhesion Molecule-1; D000077385:Silybin; D017351:N-Acetylglucosaminyltransferases; C054599:beta-1,4-mannosyl-glycoprotein beta-1,4-N-acetylglucosaminyltransferase