title: Smad-independent transforming growth factor-beta regulation of early growth response-1 and sustained expression in fibrosis: implications for scleroderma.
abstract: Transforming growth factor-beta (TGF-beta) plays a key role in scleroderma pathogenesis. The transcription factor early growth response-1 (Egr-1) mediates the stimulation of collagen transcription elicited by TGF-beta and is necessary for the development of pulmonary fibrosis in mice. Here, we report that TGF-beta causes a time- and dose-dependent increase in Egr-1 protein and mRNA levels and enhanced transcription of the Egr-1 gene via serum response elements in normal fibroblasts. The ability of TGF-beta to stimulate Egr-1 was preserved in Smad3-null mice and in explanted Smad3-null fibroblasts. The response was blocked by a specific mitogen-activated protein kinase kinase 1 (MEK1) inhibitor but not by an ALK5 kinase inhibitor. Furthermore, MEK1 was phosphorylated by TGF-beta, which was sufficient to drive Egr-1 transactivation. Stimulation by TGF-beta enhanced the transcriptional activity of Elk-1 via the MEK-extracellular signal-regulated kinase 1/2 pathway. Bleomycin-induced scleroderma in the mouse was accompanied by increased Egr-1 accumulation in lesional fibroblasts. Furthermore, biopsies of lesional skin and lung from patients with scleroderma showed increased Egr-1 levels, which were highest in early diffuse disease. Moreover, both Egr-1 mRNA and protein were elevated in explanted scleroderma skin fibroblasts in vitro. Together, these findings define a Smad-independent TGF-beta signal transduction mechanism that underlies the stimulation of Egr-1, demonstrate for the first time sustained Egr-1 up-regulation in fibrotic lesions and suggests that Egr-1 has a role in the induction and progression of fibrosis.
authors.affiliation: Division of Rheumatology, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA.
authors.forename: Swati
authors.initials: S
authors.lastname: Bhattacharyya
authors.forename: Shu-Jen
authors.initials: SJ
authors.lastname: Chen
authors.forename: Minghua
authors.initials: M
authors.lastname: Wu
authors.forename: Matthew
authors.initials: M
authors.lastname: Warner-Blankenship
authors.forename: Hongyan
authors.initials: H
authors.lastname: Ning
authors.forename: Gabriella
authors.initials: G
authors.lastname: Lakos
authors.forename: Yasuji
authors.initials: Y
authors.lastname: Mori
authors.forename: Eric
authors.initials: E
authors.lastname: Chang
authors.forename: Chihiro
authors.initials: C
authors.lastname: Nihijima
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Takehara
authors.forename: Carol
authors.initials: C
authors.lastname: Feghali-Bostwick
authors.forename: John
authors.initials: J
authors.lastname: Varga
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000818:Animals; D001761:Bleomycin; D051766:Early Growth Response Protein 1 / Q000235:genetics* / Q000378:metabolism; D005260:Female; D005347:Fibroblasts / Q000187:drug effects / Q000201:enzymology; D005355:Fibrosis; D006801:Humans; D008168:Lung / Q000378:metabolism / Q000473:pathology; D051379:Mice; D008875:Middle Aged; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D041681:NIH 3T3 Cells; D011401:Promoter Regions, Genetic / Q000235:genetics; D012595:Scleroderma, Systemic / Q000201:enzymology / Q000235:genetics* / Q000473:pathology*; D012867:Skin / Q000378:metabolism / Q000473:pathology; D051900:Smad3 Protein / Q000378:metabolism; D014158:Transcription, Genetic; D016212:Transforming Growth Factor beta / Q000494:pharmacology*; D015854:Up-Regulation / Q000187:drug effects; D050807:ets-Domain Protein Elk-1 / Q000235:genetics / Q000378:metabolism
chemical_list: D051766:Early Growth Response Protein 1; D051900:Smad3 Protein; D016212:Transforming Growth Factor beta; D050807:ets-Domain Protein Elk-1; D001761:Bleomycin; D020928:Mitogen-Activated Protein Kinases
references.citation: Genes Dev. 2005 Dec 1;19(23):2783-810
references.pmid: 16322555
references.citation: Mol Reprod Dev. 2002 Nov;63(3):282-90
references.pmid: 12237943
references.citation: J Biol Chem. 2006 Mar 24;281(12):8161-8
references.pmid: 16439363
references.citation: Cancer Gene Ther. 2006 Feb;13(2):115-24
references.pmid: 16138117
references.citation: Exp Cell Res. 2000 Aug 1;258(2):374-83
references.pmid: 10896788
references.citation: J Cell Sci. 2005 Aug 15;118(Pt 16):3573-84
references.pmid: 16105881
references.citation: Biochem J. 2003 Mar 15;370(Pt 3):1019-25
references.pmid: 12457461
references.citation: Oncogene. 2005 Dec 8;24(55):8085-92
references.pmid: 16091742
references.citation: J Exp Med. 2004 Aug 2;200(3):377-89
references.pmid: 15289506
references.citation: J Biol Chem. 1999 Dec 10;274(50):35381-7
references.pmid: 10585406
references.citation: J Clin Invest. 2004 Nov;114(9):1308-16
references.pmid: 15520863
references.citation: J Cell Sci. 2007 Dec 1;120(Pt 23):4230-40
references.pmid: 18032789
references.citation: Am J Pathol. 2004 Jul;165(1):203-17
references.pmid: 15215176
references.citation: Proc Natl Acad Sci U S A. 1998 Jul 7;95(14):8298-303
references.pmid: 9653181
references.citation: Methods Mol Med. 2005;117:69-80
references.pmid: 16118446
references.citation: Proc Natl Acad Sci U S A. 2004 Oct 12;101(41):14895-900
references.pmid: 15469929
references.citation: Curr Rheumatol Rep. 2005 Apr;7(2):150-5
references.pmid: 15760595
references.citation: FASEB J. 2003 Aug;17(11):1576-8
references.pmid: 12824291
references.citation: Science. 1996 Aug 30;273(5279):1219-21
references.pmid: 8703054
references.citation: J Cell Physiol. 2002 Dec;193(3):287-92
references.pmid: 12384981
references.citation: J Invest Dermatol. 1999 Jan;112(1):49-57
references.pmid: 9886263
references.citation: J Clin Invest. 2007 Mar;117(3):557-67
references.pmid: 17332883
references.citation: Proc Natl Acad Sci U S A. 2003 Oct 14;100(21):12319-24
references.pmid: 14530402
references.citation: J Immunol. 2006 Sep 15;177(6):4141-8
references.pmid: 16951379
references.citation: J Biol Chem. 2004 Mar 26;279(13):12647-58
references.pmid: 14722058
references.citation: Proc Natl Acad Sci U S A. 1991 Aug 1;88(15):6642-6
references.pmid: 1862087
references.citation: Gene. 2003 Oct 2;315:33-41
references.pmid: 14557062
references.citation: Methods Mol Med. 2004;102:377-93
references.pmid: 15286396
references.citation: Arthritis Rheum. 2003 Jul;48(7):1964-78
references.pmid: 12847691
references.citation: Cell. 1988 Apr 8;53(1):37-43
references.pmid: 3127059
references.citation: Arthritis Rheum. 2004 Dec;50(12):4008-21
references.pmid: 15593186
references.citation: Gene. 2004 Jan 7;324:1-14
references.pmid: 14693367
references.citation: Proc Natl Acad Sci U S A. 2003 Mar 18;100(6):3233-8
references.pmid: 12629205
references.citation: Mol Cell Biol. 1996 Jul;16(7):3545-53
references.pmid: 8668170
references.citation: Am J Physiol Lung Cell Mol Physiol. 2007 Nov;293(5):L1089-91
references.pmid: 17766585
references.citation: Am J Physiol Lung Cell Mol Physiol. 2007 May;292(5):L1297-303
references.pmid: 17494953
references.citation: Proc Natl Acad Sci U S A. 1996 Oct 15;93(21):11831-6
references.pmid: 8876223
references.citation: Circ Res. 2008 Jan 4;102(1):42-50
references.pmid: 17967787
references.citation: J Heart Lung Transplant. 2005 Dec;24(12):2235-42
references.pmid: 16364876
references.citation: Am J Pathol. 2000 Oct;157(4):1311-20
references.pmid: 11021835
references.citation: Atherosclerosis. 2003 Apr;167(2):187-94
references.pmid: 12818400
references.citation: Am J Pathol. 1999 Oct;155(4):1009-12
references.pmid: 10514380
references.citation: Oncogene. 2005 Feb 17;24(8):1423-33
references.pmid: 15608673
references.citation: Ann Thorac Surg. 2005 Mar;79(3):1010-6
references.pmid: 15734424
references.citation: Prog Nucleic Acid Res Mol Biol. 1995;50:191-224
references.pmid: 7754034
references.citation: Am J Respir Cell Mol Biol. 2001 Nov;25(5):613-9
references.pmid: 11713104
references.citation: Nat Med. 2000 Dec;6(12):1355-61
references.pmid: 11100120
references.citation: FASEB J. 2007 Mar;21(3):935-49
references.pmid: 17197388
references.citation: Circ Res. 2006 Feb 3;98(2):186-91
references.pmid: 16456111
references.citation: J Dermatol Sci. 2008 Feb;49(2):103-13
references.pmid: 17628443
references.citation: J Biol Chem. 2006 Jul 28;281(30):21183-21197
references.pmid: 16702209
references.citation: Arthritis Rheum. 2005 Mar;52(3):865-76
references.pmid: 15751056
references.citation: Ann Intern Med. 2004 Jan 6;140(1):37-50
references.pmid: 14706971
references.citation: J Biol Chem. 2000 Jul 7;275(27):20315-23
references.pmid: 10783396
references.citation: Curr Opin Rheumatol. 2007 Nov;19(6):568-73
references.pmid: 17917537
references.citation: PLoS One. 2008 Jan 16;3(1):e1452
references.pmid: 18197262
references.citation: FASEB J. 2002 Dec;16(14):1861-8
references.pmid: 12468449
references.citation: Cancer Res. 2006 Jul 1;66(13):6708-13
references.pmid: 16818645
references.citation: J Clin Invest. 2000 Mar;105(5):653-62
references.pmid: 10712437
references.citation: Nat Med. 2003 Aug;9(8):1026-32
references.pmid: 12872165
references.citation: J Invest Dermatol. 2002 Apr;118(4):704-11
references.pmid: 11918720
references.citation: Am J Physiol Lung Cell Mol Physiol. 2004 Apr;286(4):L817-25
references.pmid: 15003938
references.citation: Arthritis Rheum. 2003 Feb;48(2):348-59
references.pmid: 12571843
references.citation: EMBO J. 2006 Aug 9;25(15):3534-45
references.pmid: 16858414
references.citation: FASEB J. 2000 Oct;14(13):1870-2
references.pmid: 11023970
references.citation: J Biol Chem. 2004 Sep 24;279(39):40289-95
references.pmid: 15247255