title: Acute murine colitis reduces colonic 5-aminosalicylic acid metabolism by regulation of N-acetyltransferase-2.
abstract: Pharmacotherapy based on 5-aminosalicylic acid (5-ASA) is a preferred treatment for ulcerative colitis, but variable patient response to this therapy is observed. Inflammation can affect therapeutic outcomes by regulating the expression and activity of drug-metabolizing enzymes; its effect on 5-ASA metabolism by the colonic arylamine N-acetyltransferase (NAT) enzyme isoforms is not firmly established. We examined if inflammation affects the capacity for colonic 5-ASA metabolism and NAT enzyme expression. 5-ASA metabolism by colonic mucosal homogenates was directly measured with a novel fluorimetric rate assay. 5-ASA metabolism reported by the assay was dependent on Ac-CoA, inhibited by alternative NAT substrates (isoniazid, p-aminobenzoylglutamate), and saturable with Km (5-ASA) = 5.8 μM. A mouse model of acute dextran sulfate sodium (DSS) colitis caused pronounced inflammation in central and distal colon, and modest inflammation of proximal colon, defined by myeloperoxidase activity and histology. DSS colitis reduced capacity for 5-ASA metabolism in central and distal colon segments by 52 and 51%, respectively. Use of selective substrates of NAT isoforms to inhibit 5-ASA metabolism suggested that mNAT2 mediated 5-ASA metabolism in normal and colitis conditions. Western blot and real-time RT-PCR identified that proximal and distal mucosa had a decreased mNAT2 protein-to-mRNA ratio after DSS. In conclusion, an acute colonic inflammation impairs the expression and function of mNAT2 enzyme, thereby diminishing the capacity for 5-ASA metabolism by colonic mucosa.
authors.affiliation: Department of Molecular and Cellular Physiology, University of Cincinnati, Cincinnati, Ohio.
authors.forename: Verónica
authors.initials: V
authors.lastname: Ramírez-Alcántara
authors.affiliation: Department of Molecular and Cellular Physiology, University of Cincinnati, Cincinnati, Ohio montromh@ucmail.uc.edu.
authors.forename: Marshall H
authors.initials: MH
authors.lastname: Montrose
mesh_terms: D000818:Animals; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000378:metabolism; D001191:Arylamine N-Acetyltransferase / Q000235:genetics / Q000378:metabolism*; D003092:Colitis / Q000139:chemically induced / Q000473:pathology*; D003106:Colon / Q000378:metabolism*; D016264:Dextran Sulfate / Q000633:toxicity; D015971:Gene Expression Regulation, Enzymologic / Q000502:physiology*; D006801:Humans; D007413:Intestinal Mucosa / Q000201:enzymology / Q000473:pathology; D008297:Male; D019804:Mesalamine / Q000378:metabolism*; D051379:Mice; D008810:Mice, Inbred C57BL
chemical_list: D000894:Anti-Inflammatory Agents, Non-Steroidal; D019804:Mesalamine; D016264:Dextran Sulfate; D001191:Arylamine N-Acetyltransferase; C524206:Nat2 enzyme, mouse
keywords: dextran sulfate sodium; drug metabolism; enzymatic assay; enzyme isoform; fluorescence; inflammatory bowel disease; kinetics; myeloperoxidase
references.citation: Biochim Biophys Acta. 1988 Aug 3;948(1):37-66
references.pmid: 3293663
references.citation: Inflamm Bowel Dis. 2003 Nov;9(6):363-71
references.pmid: 14671485
references.citation: Eur J Pharmacol. 2008 Mar 10;581(3):315-23
references.pmid: 18215658
references.citation: Biochem Biophys Res Commun. 2003 Aug 8;307(4):1059-65
references.pmid: 12878219
references.citation: Drug Discov Today. 2011 May;16(9-10):435-42
references.pmid: 21376135
references.citation: Gut. 1992 Oct;33(10):1353-7
references.pmid: 1446859
references.citation: J Chromatogr. 1991 Mar 8;564(1):296-302
references.pmid: 1860925
references.citation: J Pharmacol Exp Ther. 2006 Nov;319(2):724-8
references.pmid: 16857729
references.citation: Aliment Pharmacol Ther. 2009 Nov 15;30(10):1078-86
references.pmid: 19735230
references.citation: Gut. 1992 Oct;33(10):1338-42
references.pmid: 1446856
references.citation: Aliment Pharmacol Ther. 1999 Mar;13(3):363-72
references.pmid: 10102970
references.citation: Dig Dis Sci. 1985 Dec;30(12):1161-5
references.pmid: 2866075
references.citation: Gastroenterology. 1984 Dec;87(6):1344-50
references.pmid: 6092199
references.citation: Biochem Pharmacol. 1994 Mar 2;47(5):914-7
references.pmid: 8135868
references.citation: Gastroenterology. 2004 May;126(6):1504-17
references.pmid: 15168363
references.citation: Biochem Pharmacol. 1994 May 18;47(10):1897-902
references.pmid: 8204107
references.citation: Gastroenterology. 1989 Mar;96(3):811-6
references.pmid: 2563347
references.citation: World J Gastroenterol. 2007 Dec 14;13(46):6219-25
references.pmid: 18069763
references.citation: Drug Metab Dispos. 1993 Nov-Dec;21(6):1057-63
references.pmid: 7905384
references.citation: Cancer Epidemiol Biomarkers Prev. 2000 Jan;9(1):29-42
references.pmid: 10667461
references.citation: Agents Actions. 1973 Dec;3(5):312-6
references.pmid: 4206379
references.citation: Gut. 1998 Mar;42(3):402-9
references.pmid: 9577349
references.citation: Mol Pharmacol. 2000 Mar;57(3):468-73
references.pmid: 10692486
references.citation: Aliment Pharmacol Ther. 1988 Feb;2(1):33-40
references.pmid: 2979230
references.citation: Scand J Gastroenterol. 1992 Nov;27(11):968-72
references.pmid: 1455196
references.citation: Aliment Pharmacol Ther. 1988 Jun;2(3):203-11
references.pmid: 2908754
references.citation: Clin Sci (Lond). 1990 Jan;78(1):105-11
references.pmid: 2153487
references.citation: J Exp Med. 2005 Apr 18;201(8):1205-15
references.pmid: 15824083
references.citation: Gastroenterology. 1989 Jul;97(1):38-41
references.pmid: 2566551
references.citation: Biochem Pharmacol. 1992 Jan 22;43(2):259-62
references.pmid: 1310851
references.citation: Scand J Gastroenterol. 1980;15(6):715-9
references.pmid: 7010522
references.citation: Gastroenterology. 1997 Nov;113(5):1474-9
references.pmid: 9352849
references.citation: Biochem Pharmacol. 2005 Jan 15;69(2):347-59
references.pmid: 15627487
references.citation: J Chromatogr B Analyt Technol Biomed Life Sci. 2008 Sep 1;872(1-2):99-106
references.pmid: 18691952
references.citation: Z Gastroenterol. 2008 Mar;46(3):259-65
references.pmid: 18322880
references.citation: Biochem J. 1994 Sep 1;302 ( Pt 2):347-53
references.pmid: 7545952
references.citation: J Biol Chem. 2003 Sep 12;278(37):35086-92
references.pmid: 12832400
references.citation: Cancer Lett. 1999 Sep 1;143(2):99-102
references.pmid: 10503885
references.citation: Drug Metab Dispos. 1998 May;26(5):502-5
references.pmid: 9571233
references.citation: Pharmacogenomics J. 2003;3(3):169-77
references.pmid: 12815365
references.citation: Immunopharmacology. 1988 Jan-Feb;15(1):39-46
references.pmid: 2896181
references.citation: Drug Metab Dispos. 2008 Feb;36(2):205-16
references.pmid: 18218849
references.citation: Drug Metab Rev. 2008;40(3):479-510
references.pmid: 18642144
references.citation: Gut. 1992 Jan;33(1):59-64
references.pmid: 1740279
references.citation: J Chromatogr A. 2006 Jun 30;1119(1-2):299-308
references.pmid: 16466733
references.citation: J Pharmacol Exp Ther. 1978 Jan;204(1):212-8
references.pmid: 619131
references.citation: Free Radic Biol Med. 1991;10(1):41-9
references.pmid: 1675620
references.citation: Pharmacogenetics. 1997 Apr;7(2):121-30
references.pmid: 9170149
references.citation: J Biol Chem. 1999 Sep 10;274(37):26448-53
references.pmid: 10473604
references.citation: Am J Gastroenterol. 2011 Apr;106(4):617-29
references.pmid: 21407190
references.citation: Biomed Chromatogr. 2005 Jun;19(5):350-4
references.pmid: 15586374
references.citation: Dig Dis Sci. 1994 Jan;39(1):145-51
references.pmid: 8281849
references.citation: Biochem Pharmacol. 1996 Nov 22;52(10):1613-20
references.pmid: 8937477
references.citation: Gut. 1992 Oct;33(10):1343-7
references.pmid: 1446857
references.citation: DNA Cell Biol. 1990 Apr;9(3):193-203
references.pmid: 2340091
references.citation: Mol Interv. 2007 Apr;7(2):99-111
references.pmid: 17468390
references.citation: Eur J Clin Invest. 2007 Jul;37(7):558-65
references.pmid: 17576207
references.citation: Lab Anim. 1981 Jan;15(1):57-9
references.pmid: 7022018
references.citation: J Gastroenterol. 2004 Jun;39(6):514-9
references.pmid: 15235867
references.citation: Biochem J. 1995 Apr 1;307 ( Pt 1):1-3
references.pmid: 7717963
references.citation: Biochem J. 1973 Mar;132(3):519-26
references.pmid: 4724587
references.citation: Pharmacogenomics. 2002 Jan;3(1):19-30
references.pmid: 11966400
references.citation: Am J Gastroenterol. 2002 Jul;97(7):1763-8
references.pmid: 12135032
references.citation: Aliment Pharmacol Ther. 2001 Jan;15(1):53-62
references.pmid: 11136278
references.citation: Xenobiotica. 1991 May;21(5):605-12
references.pmid: 1949893
references.citation: Agents Actions. 1987 Jun;21(1-2):191-4
references.pmid: 2888280