Human collagen Krox up-regulates type I collagen expression in normal and scleroderma fibroblasts through interaction with Sp1 and Sp3 transcription factors.
Despite several investigations, the transcriptional mechanisms that regulate the expression of both type I collagen genes (COL1A1 and COL1A2) in either physiological or pathological situations, such as scleroderma, are not completely known. We have investigated the role of hc-Krox transcription factor on type I collagen expression by human dermal fibroblasts. hc-Krox exerted a stimulating effect on type I collagen protein synthesis and enhanced the corresponding mRNA steady-state levels of COL1A1 and COL1A2 in foreskin fibroblasts (FF), adult normal fibroblasts (ANF), and scleroderma fibroblasts (SF). Forced hc-Krox expression was found to up-regulate COL1A1 transcription through a -112/-61-bp sequence in FF, ANF, and SF. Knockdown of hc-Krox by short interfering RNA and decoy strategies confirmed the transactivating effect of hc-Krox and decreased substantially COL1A1 transcription levels in all fibro-blast types. The -112/-61-bp sequence bound specifically hc-Krox but also Sp1 and CBF. Attempts to elucidate the potential interactions between hc-Krox, Sp1, and Sp3 revealed that all of them co-immunoprecipitate from FF cellular extracts when a c-Krox antibody was used and bind to the COL1A1 promoter in chromatin immunoprecipitation assays. Moreover, hc-Krox DNA binding activity to its COL1A1-responsive element is increased in SF, cells producing higher amounts of type I collagen compared with ANF and FF. These data suggest that the regulation of COL1A1 gene transcription in human dermal fibroblasts involves a complex machinery that implicates at least three transcription proteins, hc-Krox, Sp1, and Sp3, which could act in concert to up-regulate COL1A1 transcriptional activity and provide evidence for a pro-fibrotic role of hc-Krox.
Kypriotou
Magdalini
M
Laboratoire de Biochimie du Tissu Conjonctif, Université de Caen/Basse-Normandie, IFR ICORE 146, FacultédeMédecine, CHU Niveau 3, Avenue de la Côte de Nacre, 14032 Caen Cedex, France.
Beauchef
Gallic
G
Chadjichristos
Christos
C
Widom
Russell
R
Renard
Emmanuelle
E
Jimenez
Sergio A
SA
Korn
Joseph
J
Maquart
François-Xavier
FX
Oddos
Thierry
T
Von Stetten
Otto
O
Pujol
Jean-Pierre
JP
Galéra
Philippe
P
D000328:Adult; D001483:Base Sequence; D002648:Child; D024042:Collagen Type I / Q000235:genetics*; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D005347:Fibroblasts / Q000378:metabolism*; D052816:Foreskin / Q000166:cytology / Q000378:metabolism; D006801:Humans; D008297:Male; D008969:Molecular Sequence Data; D034622:RNA Interference; D034741:RNA, Small Interfering; D012595:Scleroderma, Systemic; D012867:Skin / Q000166:cytology / Q000378:metabolism; D016329:Sp1 Transcription Factor / Q000378:metabolism*; D051705:Sp3 Transcription Factor / Q000378:metabolism*; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D014158:Transcription, Genetic; D015854:Up-Regulation
D024042:Collagen Type I; D004268:DNA-Binding Proteins; D034741:RNA, Small Interfering; D016329:Sp1 Transcription Factor; D014157:Transcription Factors; C484225:ZBTB7B protein, human; D051705:Sp3 Transcription Factor