The p65 Subunit of NF-κB Inhibits COL1A1 Gene Transcription in Human Dermal and Scleroderma Fibroblasts through Its Recruitment on Promoter by Protein Interaction with Transcriptional Activators (c-Krox, Sp1, and Sp3)

• Published in: The Journal of biological chemistry 2012-01, Vol.287 (5), p.3462-3478
• Main Authors: Beauchef, Gallic, Bigot, Nicolas, Kypriotou, Magdalini, Renard, Emmanuelle, Porée, Benoît, Widom, Russell, Dompmartin-Blanchere, Anne, Oddos, Thierry, Maquart, François-Xavier, Demoor, Magali, Boumediene, Karim, Galera, Philippe
• Format: Article
• Language: English
• Subjects: Adult; Child; Child, Preschool; Collagen; Collagen Type I - biosynthesis; Collagen Type I - genetics; Dermis - metabolism; Dermis - pathology; DNA-Binding Proteins - genetics; DNA-Binding Proteins - metabolism; Fibroblast; Fibroblasts - metabolism; Fibroblasts - pathology; Fibrosis; Gene Expression Regulation - genetics; Gene Regulation; Gene Transcription; Humans; Life Sciences; Male; Nuclear Factor-κB; Response Elements; Scleroderma; Scleroderma, Localized - metabolism; Scleroderma, Localized - pathology; Skin; Sp1; Sp1 Transcription Factor - genetics; Sp1 Transcription Factor - metabolism; Sp3 Transcription Factor - genetics; Sp3 Transcription Factor - metabolism; Transcription Factor RelA - genetics; Transcription Factor RelA - metabolism; Transcription Factors - genetics; Transcription Factors - metabolism; Transcription Factors, Sp3, c-Krox; Transcription, Genetic; Type I Collagen
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1074/jbc.M111.286443

Transcriptional mechanisms regulating type I collagen genes expression in physiopathological situations are not completely known. In this study, we have investigated the role of nuclear factor-κB (NF-κB) transcription factor on type I collagen expression in adult normal human (ANF) and scleroderma (SF) fibroblasts. We demonstrated that NF-κB, a master transcription factor playing a major role in immune response/apoptosis, down-regulates COL1A1 expression by a transcriptional control involving the −112/−61 bp sequence. This 51-bp region mediates the action of two zinc fingers, Sp1 (specific protein-1) and Sp3, acting as trans-activators of type I collagen expression in ANF and SF. Knockdown of each one of these trans factors by siRNA confirmed the trans-activating effect of Sp1/Sp3 and the p65 subunit of NF-κB trans-inhibiting effect on COL1A1 expression. Despite no existing κB consensus sequence in the COL1A1 promoter, we found that Sp1/Sp3/c-Krox and NF-κB bind and/or are recruited on the proximal promoter in chromatin immunoprecipitation (ChIP) assays. Attempts to elucidate whether interactions between Sp1/Sp3/c-Krox and p65 are necessary to mediate the NF-κB inhibitory effect on COL1A1 in ANF and SF were carried out; in this regard, immunoprecipitation assays revealed that they interact, and this was validated by re-ChIP. Finally, the knockdown of Sp1/Sp3/c-Krox prevents the p65 inhibitory effect on COL1A1 transcription in ANF, whereas only the siRNAs targeting Sp3 and c-Krox provoked the same effect in SF, suggesting that particular interactions are characteristic of the scleroderma phenotype. In conclusion, our findings highlight a new mechanism for COL1A1 transcriptional regulation by NF-κB, and these data could allow the development of new antifibrotic strategies. Background: NF-κB regulation of COL1A1 in physiopathological situations is largely unknown. Results: NF-κB down-regulates COL1A1 in normal and scleroderma fibroblasts, through its recruitment on COL1A1 by protein interactions with the Sp1/Sp3/c-Krox trans-activators, which are different in fibrotic fibroblasts. Conclusion: Our findings highlight a new mechanism for COL1A1 regulation. Significance: These data could allow the development of new antifibrotic strategies.