Egr-1 Mediates Transcriptional Repression of COL2A1Promoter Activity by Interleukin-1β

Tan, Lujian; Peng, Haibing; Osaki, Makoto; Choy, Bob K.; Auron, Philip E.; Sandell, Linda J.; Goldring, Mary B.

doi:10.1074/jbc.m301676200

Cited by 117 publications

(130 citation statements)

References 75 publications

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“…19 pCMV Egr-1 or pCMV Egr-2 contains the full-length Egr-1 or Egr-2 coding sequence, respectively. 20 772COL1A2-CAT harbors the truncated human COL1A2 promoter with 5= ends at Ϫ772 bp fused to chloramphenicol acetyltransferase (CAT). 21 4 -luc harbors four copies of the minimal Egr-1-responsive element linked to luc.…”

Section: Plasmids and Transient Transfection Assaysmentioning

confidence: 99%

The Early Growth Response Gene Egr2 (Alias Krox20) Is a Novel Transcriptional Target of Transforming Growth Factor-β that Is Up-Regulated in Systemic Sclerosis and Mediates Profibrotic Responses

Fang

Ooka

Bhattachyya

et al. 2011

The American Journal of Pathology

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Although the early growth response-2 (Egr-2, alias Krox20) protein shows structural and functional similarities to Egr-1, these two related early-immediate transcription factors are nonredundant. Egr-2 plays essential roles in peripheral nerve myelination, adipogenesis, and immune tolerance; however, its regulation and role in tissue repair and fibrosis remain poorly understood. We show herein that transforming growth factor (TGF)-␤ induced a Smad3-dependent sustained stimulation of Egr2 gene expression in normal fibroblasts. Overexpression of Egr-2 was sufficient to stimulate collagen gene expression and myofibroblast differentiation, whereas these profibrotic TGF-␤ responses were attenuated in Egr-2-depleted fibroblasts. Genomewide transcriptional profiling revealed that multiple genes associated with tissue remodeling and wound healing were up-regulated by Egr-2, but the Egr-2-regulated gene expression profile overlapped only partially with the Egr-1-regulated gene profile. Levels of Egr-2 were elevated in lesional tissue from mice with bleomycin-induced scleroderma. Moreover, elevated Egr-2 was noted in biopsy specimens of skin and lung from patients with systemic sclerosis.These results provide the first evidence that Egr-2 is a functionally distinct transcription factor that is both necessary and sufficient for TGF-␤-induced profibrotic responses and is aberrantly expressed in lesional tissue in systemic sclerosis and in a murine model of scleroderma. Together, these findings suggest that Egr-2 plays an important nonredundant role in the pathogenesis of fibrosis. Targeting Egr-2 might represent a novel therapeutic strategy to control fibrosis.

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Section: Plasmids and Transient Transfection Assaysmentioning

confidence: 99%

The Early Growth Response Gene Egr2 (Alias Krox20) Is a Novel Transcriptional Target of Transforming Growth Factor-β that Is Up-Regulated in Systemic Sclerosis and Mediates Profibrotic Responses

Fang

Ooka

Bhattachyya

et al. 2011

The American Journal of Pathology

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“…Consistent with its role as an immediate early gene, Egr-1 mRNA levels rise and peak early after stimulation with insulin then decline quickly, with a corresponding pattern of protein expression (Figure 1). This time course of insulin induced increase in Egr-1 mRNA levels has been observed in many tissues (Barroso and Santisteban, 1999;Tan et al, 2003;Silverman and Collins, 1999;Leung-Theung-Long et al, 2005;Garnett et al, 2005) as has its dependence on the MAP kinase pathway (Leung-Theung-Long et al, 2005;Garnett et al, 2005;Keeton et al, 2003). The GnRH mRNA level peak after one hour of insulin treatment corresponds with the time of maximal Egr-1 protein levels, suggesting that higher protein levels, rather than protein activation, promote binding of Egr-1 to the GnRH promoter.…”

Section: Discussionmentioning

confidence: 61%

“…A variety of factors can stimulate Egr-1 gene expression, including cellular injury, radiation, and growth factors (Gashler and Sukhatme, 1995). Insulin regulates Egr-1 gene expression in a variety of tissues including hepatic, bone, pancreatic beta cells and vascular endothelial tissue (Barroso and Santisteban, 1999;Tan et al, 2003;Silverman and Collins, 1999;Leung-Theung-Long et al, 2005;Garnett et al, 2005). The induction of Egr-1 gene expression by insulin is primarily mediated by the MAP kinase pathway.…”

Section: Introductionmentioning

confidence: 99%

Egr-1 binds the GnRH promoter to mediate the increase in gene expression by insulin

DiVall

Radovick

Wolfe

2007

Molecular and Cellular Endocrinology

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SUMMARYInsulin increases gonadotropin-releasing hormone (GnRH) gene expression in in vitro models of GnRH neurons. Early growth response-1 (Egr-1) is a transcription factor that mediates the effect of insulin on target genes. In the GN11 cell line-an immortalized GnRH-secreting neuronal cell line -insulin maximally increases Egr-1 mRNA after 30 minutes of treatment and Egr-1 protein and GnRH mRNA after 60 minutes of treatment. Egr-1 small interfering RNA blocks the insulin-induced increase in GnRH promoter activity, measured as luciferase expression. Chromatin immunoprecipitation using Egr-1 antibody precipitates DNA in a proximal region of the GnRH promoter but not DNA in a distal region. Mutagenesis of a putative Egr-1 binding site within the proximal region blocks the insulin-induced increase in GnRH promoter activity. Thus, Egr-1 binds the GnRH promoter at a site between −67 and −76 bp from the transcriptional start site to mediate the insulin induced increase in GnRH gene transcription.

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“…C-28/I2 cells were plated at a density of 3 ϫ 10 4 /cm 2 and cultured overnight. The cells were cotransfected with the pGL4-basic vector containing Ϫ1,359 bp of the 5Ј-flanking region of the human MMP-13 promoter and pCMV-LAP, an expression vector of rat C/EBP␤-LAP directed by a cytomegalovirus promoter (29), in a dose-dependent manner (0, 0.01, 0.05, 0.1, and 0.2 g) using Lipofectamine Plus reagent (Life Technologies, Rockville, MD) as previously described (13). A green fluorescent protein (GFP) expression vector, pEGFP-C1 (BD Biosciences), was also used to adjust the total amount of transfected DNA.…”

Section: Methodsmentioning

confidence: 99%

“…These pathways lead directly to the deterioration of cartilage matrix structures. IL-1␤ and TNF␣ treatment of chondrocytes induces many transcription factors related to inflammation, such as NF-B, IKK, activator protein 1 (AP-1) (11,12), early growth response 1 (13), and members of the CCAAT/enhancer binding protein (C/EBP) family (14).…”

mentioning

confidence: 99%

CCAAT/ENHANCER binding protein β mediates expression of matrix metalloproteinase 13 in human articular chondrocytes in inflammatory arthritis

Hayashida¹,

Okazaki²,

Fukushi³

et al. 2009

Arthritis & Rheumatism

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Objective. To determine the function of CCAAT/ enhancer binding protein ␤ (C/EBP␤) in the expression of matrix metalloproteinase 13 (MMP-13) in chondrocytes in inflammatory arthritis.Methods. Cartilage obtained from patients with rheumatoid arthritis and osteoarthritis was immunostained for expression of C/EBP␤ or MMP-13. Interleukin-1␤-or tumor necrosis factor ␣ (TNF␣)-stimulated chondrocytes were subjected to Western blotting and real-time reverse transcriptase-polymerase chain reaction (RT-PCR). MMP-13 promoter assays were conducted, and the C/EBP␤ response element was characterized by deletion and mutation analysis. C-28/I2 cells were treated with TNF␣ and subjected to chromatin immunoprecipitation (ChIP) assays. Finally, C/EBP␤-liver-enriched activator protein (LAP) was overexpressed in C-28/I2 cells or cartilage tissues, and MMP-13 expression was analyzed.Results. C/EBP␤ and MMP-13 expression was colocalized in chondrocytes in arthritic cartilage. MMP-13 promoter activity was stimulated by C/EBP␤ overexpression in a dose-dependent manner. Luciferase assays revealed that a -981-bp promoter had the greatest activity, while deletion to -936 bp strongly diminished promoter activity. Luciferase activity was repressed to basal levels by mutations in potential C/EBP binding sites. The stimulatory effects of C/EBP␤ overexpression were diminished by mutation. ChIP assays revealed that TNF␣ treatment enhanced the binding of C/EBP␤ to the MMP-13 promoter. When C/EBP␤-LAP was overexpressed in C-28/I2 cells, endogenous MMP-13 expression was stimulated up to 32-fold as detected by real-time RT-PCR. Furthermore, following adenoviral overexpression of C/EBP␤-LAP in organ culture of articular cartilage, stimulation of MMP-13 was also detected by immunohistochemistry. Conclusion. C/EBP␤ directly binds to the MMP-13 promoter region and stimulates the expression of MMP-13 in chondrocytes in inflammatory arthritis.Degeneration of articular cartilage is the principal process causing disability in patients with inflammatory arthritis, including those with rheumatoid arthritis (RA) (1,2) and osteoarthritis (OA) (3,4). Normally, maintenance of the cartilage extracellular matrix (ECM) is strictly regulated by the balance of anabolic and catabolic factors secreted by synovial cells or by chondrocytes themselves. Arthritic cartilage is characterized by excessive production of proteinases, such as matrix metalloproteinases (MMPs) and aggrecanases, and reduced synthesis of new matrix by chondrocytes, which disturbs the balance of anabolic and catabolic factors. Among the proteinases, MMP-13 cleaves a broad range of substrates, including fibrillar type II collagen and type II procollagen as well as gelatin, types I, III, IV, IX, X, and XIV collagen, tenascin, fibronectin, fibronectin fragments, and aggrecan (5-8). It has been reported that MMP-13 has the highest degradation activity for type II collagen (5,9). A recent study showed that up-regulated transgenic expression of MMP-13 in mouse articular cartilage resulted in pathologic chan...

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Egr-1 Mediates Transcriptional Repression of COL2A1Promoter Activity by Interleukin-1β

Cited by 117 publications

References 75 publications

The Early Growth Response Gene Egr2 (Alias Krox20) Is a Novel Transcriptional Target of Transforming Growth Factor-β that Is Up-Regulated in Systemic Sclerosis and Mediates Profibrotic Responses

The Early Growth Response Gene Egr2 (Alias Krox20) Is a Novel Transcriptional Target of Transforming Growth Factor-β that Is Up-Regulated in Systemic Sclerosis and Mediates Profibrotic Responses

Egr-1 binds the GnRH promoter to mediate the increase in gene expression by insulin

CCAAT/ENHANCER binding protein β mediates expression of matrix metalloproteinase 13 in human articular chondrocytes in inflammatory arthritis

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