title: Ultraviolet irradiation induces CYR61/CCN1, a mediator of collagen homeostasis, through activation of transcription factor AP-1 in human skin fibroblasts.
abstract: UV irradiation from the sun elevates the production of collagen-degrading matrix metalloproteinases (MMPs) and reduces the production of new collagen. This imbalance of collagen homeostasis impairs the structure and function of the dermal collagenous extracellular matrix (ECM), thereby promoting premature skin aging (photoaging). We report here that aberrant dermal collagen homeostasis in UV-irradiated human skin is mediated in part by a CCN-family member, cysteine-rich protein-61 (CYR61/CCN1). CYR61 is significantly elevated in acutely UV-irradiated human skin in vivo, and UV-irradiated human skin fibroblasts. Knockdown of CYR61 significantly attenuates UV irradiation-induced inhibition of type-I procollagen and upregulation of MMP-1. Determination of CYR61 mRNA and protein indicates that the primary mechanism of CYR61 induction by UV irradiation is transcriptional. Analysis of CYR61 proximal promoter showed that a sequence conforming to the consensus binding site for transcription factor activator protein-1 (AP-1) is required for promoter activity. UV irradiation increased the binding of AP-1-family members c-Jun and c-Fos to this AP-1 site. Furthermore, functional blockade of c-Jun or knockdown of c-Jun significantly reduced the UV irradiation-induced activation of CYR61 promoter and CYR61 gene expression. These data show that CYR61 is transcriptionally regulated by UV irradiation through transcription factor AP-1, and mediates altered collagen homeostasis that occurs in response to UV irradiation in human skin fibroblasts.
authors.affiliation: Department of Dermatology, University of Michigan Medical School, 1301 E. Catherine, Ann Arbor, MI 48109, USA. thquan@umich.edu
authors.forename: Taihao
authors.initials: T
authors.lastname: Quan
authors.forename: Zhaoping
authors.initials: Z
authors.lastname: Qin
authors.forename: Yiru
authors.initials: Y
authors.lastname: Xu
authors.forename: Tianyuan
authors.initials: T
authors.lastname: He
authors.forename: Sewon
authors.initials: S
authors.lastname: Kang
authors.forename: John J
authors.initials: JJ
authors.lastname: Voorhees
authors.forename: Gary J
authors.initials: GJ
authors.lastname: Fisher
mesh_terms: D000328:Adult; D001706:Biopsy; D002478:Cells, Cultured; D003094:Collagen / Q000378:metabolism*; D055515:Cysteine-Rich Protein 61 / Q000378:metabolism*; D005347:Fibroblasts / Q000378:metabolism* / Q000473:pathology / Q000528:radiation effects; D006706:Homeostasis / Q000528:radiation effects*; D006801:Humans; D020781:Matrix Metalloproteinase 1 / Q000378:metabolism; D016760:Proto-Oncogene Proteins c-fos / Q000378:metabolism; D016755:Proto-Oncogene Proteins c-jun / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D012867:Skin / Q000378:metabolism* / Q000473:pathology / Q000528:radiation effects; D018808:Transcription Factor AP-1 / Q000378:metabolism*; D014466:Ultraviolet Rays
chemical_list: C501848:CCN1 protein, human; D055515:Cysteine-Rich Protein 61; D016760:Proto-Oncogene Proteins c-fos; D016755:Proto-Oncogene Proteins c-jun; D012333:RNA, Messenger; D018808:Transcription Factor AP-1; D003094:Collagen; D020781:Matrix Metalloproteinase 1