title: Cooperative role of NF-{kappa}B and poly(ADP-ribose) polymerase 1 (PARP-1) in the TNF-induced inhibition of PHEX expression in osteoblasts.
abstract: Reduced bone mass is a common complication in chronic inflammatory diseases, although the mechanisms are not completely understood. The PHEX gene encodes a zinc endopeptidase expressed in osteoblasts and contributes to bone mineralization. The aim of this study was to determine the molecular mechanism involved in TNF-mediated down-regulation of Phex gene transcription. We demonstrate down-regulation of the Phex gene in two models of colitis: naive T-cell transfer and in gnotobiotic IL-10(-/-) mice. In vitro, TNF decreased expression of Phex in UMR106 cells and did not require de novo synthesis of a transrepressor. Transfecting UMR-106 cells with a series of deletion constructs of the proximal Phex promoter identified a region located within -74 nucleotides containing NF-κB and AP-1 binding sites. After TNF treatment, the RelA/p50 NF-κB complex interacted with two cis-elements at positions -70/-66 and -29/-25 nucleotides in the proximal Phex promoter. Inhibition of NF-κB signaling increased the basal level of Phex transcription and abrogated the effects of TNF, whereas overexpression of RelA mimicked the effect of TNF. We identified poly(ADP-ribose) polymerase 1 (PARP-1) binding immediately upstream of the NF-κB sites and showed that TNF induced poly(ADP-ribosyl)ation of RelA when bound to the Phex promoter. TNF-mediated Phex down-regulation was completely abrogated in vitro by PARP-1 inhibitor and overexpression of poly(ADP-ribose) glucohydrolase (PARG) and in vivo in PARP-1(-/-) mice. Our results suggest that NF-κB signaling and PARP-1 enzymatic activity cooperatively contribute to the constitutive and inducible suppression of Phex. The described phenomenon likely contributes to the loss of bone mass density in chronic inflammatory diseases, such as inflammatory bowel disease.
authors.affiliation: Department of Pediatrics, Steele Children's Research Center, University of Arizona Health Sciences Center, Tucson, Arizona 85724, USA.
authors.forename: Pawel M
authors.initials: PM
authors.lastname: Majewski
authors.forename: Robert D
authors.initials: RD
authors.lastname: Thurston
authors.forename: Rajalakshmy
authors.initials: R
authors.lastname: Ramalingam
authors.forename: Pawel R
authors.initials: PR
authors.lastname: Kiela
authors.forename: Fayez K
authors.initials: FK
authors.lastname: Ghishan
mesh_terms: D000818:Animals; D002113:Calcification, Physiologic / Q000235:genetics; D002460:Cell Line; D003092:Colitis / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D004195:Disease Models, Animal; D015971:Gene Expression Regulation, Enzymologic; D005856:Germ-Free Life; D006801:Humans; D016753:Interleukin-10 / Q000235:genetics / Q000378:metabolism; D051379:Mice; D018345:Mice, Knockout; D010006:Osteoblasts / Q000378:metabolism* / Q000473:pathology; D053402:PHEX Phosphate Regulating Neutral Endopeptidase / Q000096:biosynthesis* / Q000235:genetics; D000071137:Poly (ADP-Ribose) Polymerase-1; D011065:Poly(ADP-ribose) Polymerases / Q000235:genetics / Q000378:metabolism*; D020218:Response Elements / Q000235:genetics; D051996:Transcription Factor RelA / Q000235:genetics / Q000378:metabolism*; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism*
chemical_list: C508609:IL10 protein, human; C498143:RELA protein, human; C498144:Rela protein, mouse; D051996:Transcription Factor RelA; D014409:Tumor Necrosis Factor-alpha; D016753:Interleukin-10; C499320:PARP1 protein, human; C499321:Parp1 protein, mouse; D000071137:Poly (ADP-Ribose) Polymerase-1; D011065:Poly(ADP-ribose) Polymerases; D053402:PHEX Phosphate Regulating Neutral Endopeptidase; C506231:PHEX protein, human; C506232:Phex protein, mouse
references.citation: Eur J Endocrinol. 2002 Jan;146(1):97-105
references.pmid: 11751074
references.citation: Gastroenterology. 2004 Sep;127(3):792-801
references.pmid: 15362035
references.citation: Am J Physiol Gastrointest Liver Physiol. 2008 Nov;295(5):G1079-91
references.pmid: 18818316
references.citation: Am J Physiol Gastrointest Liver Physiol. 2000 Sep;279(3):G641-51
references.pmid: 10960365
references.citation: Gastroenterology. 2010 Apr;138(4):1384-94, 1394.e1-2
references.pmid: 20004202
references.citation: Lab Invest. 2009 Jan;89(1):7-14
references.pmid: 19029978
references.citation: Autoimmun Rev. 2009 Jan;8(3):250-5
references.pmid: 18722561
references.citation: J Bone Miner Res. 2008 Oct;23(10):1638-49
references.pmid: 18597632
references.citation: Gut. 2008 May;57(5):684-94
references.pmid: 18408105
references.citation: Immunology. 2004 Dec;113(4):509-17
references.pmid: 15554929
references.citation: J Bone Miner Res. 2010 Apr;25(4):695-705
references.pmid: 19775205
references.citation: Annu Rev Nutr. 2005;25:197-214
references.pmid: 16011465
references.citation: Am J Physiol. 1995 Sep;269(3 Pt 2):F439-48
references.pmid: 7573493
references.citation: Biochem Biophys Res Commun. 2001 Jun 22;284(4):977-81
references.pmid: 11409890
references.citation: Free Radic Biol Med. 2009 Jul 1;47(1):13-26
references.pmid: 19362586
references.citation: Am J Physiol. 1998 Oct;275(4):E700-8
references.pmid: 9755091
references.citation: J Pediatr Gastroenterol Nutr. 2002 Nov;35(5):641-8
references.pmid: 12454579
references.citation: Inflamm Bowel Dis. 2008 Jan;14(1):114-24
references.pmid: 17763472
references.citation: Bone. 2004 Aug;35(2):455-62
references.pmid: 15268897
references.citation: Biotechniques. 2000 May;28(5):938-42
references.pmid: 10818701
references.citation: Hum Mol Genet. 1997 Feb;6(2):165-71
references.pmid: 9063736
references.citation: J Pharmacol Exp Ther. 2002 Dec;303(3):1145-54
references.pmid: 12438538
references.citation: World J Gastroenterol. 2007 Dec 14;13(46):6156-65
references.pmid: 18069754
references.citation: Prog Biophys Mol Biol. 2005 May;88(1):143-72
references.pmid: 15561303
references.citation: Am J Physiol Renal Physiol. 2002 Aug;283(2):F356-63
references.pmid: 12110521
references.citation: BMC Genomics. 2007 Feb 07;8:41
references.pmid: 17286852
references.citation: J Biol Chem. 2003 Sep 26;278(39):37419-26
references.pmid: 12874285
references.citation: Eur J Pharmacol. 2007 Jun 1;563(1-3):216-23
references.pmid: 17374531
references.citation: Nat Med. 2009 Jun;15(6):682-9
references.pmid: 19448637
references.citation: J Pediatr Gastroenterol Nutr. 1997 Mar;24(3):289-95
references.pmid: 9138175
references.citation: Nucleic Acids Res. 2003 Jul 1;31(13):3576-9
references.pmid: 12824369
references.citation: Cell Signal. 2008 Jan;20(1):186-94
references.pmid: 17993261
references.citation: J Biol Chem. 2004 Nov 5;279(45):46406-14
references.pmid: 15337762
references.citation: Mol Cell. 2009 Nov 13;36(3):365-78
references.pmid: 19917246
references.citation: Gastroenterology. 2006 Aug;131(2):497-509
references.pmid: 16890604
references.citation: Bone. 2005 Oct;37(4):589-98
references.pmid: 16084134
references.citation: Endocrinology. 2008 Apr;149(4):1757-72
references.pmid: 18162525
references.citation: Circulation. 2007 May 8;115(18):2442-50
references.pmid: 17438151
references.citation: Eur J Pharmacol. 2005 Dec 19;527(1-3):163-71
references.pmid: 16310767
references.citation: Endocrinology. 2003 Nov;144(11):4876-85
references.pmid: 12960044
references.citation: Eur J Pharmacol. 2003 May 23;469(1-3):183-94
references.pmid: 12782201