title: Signaling of short- and long-term regulation of intestinal epithelial type 1 Na+/H+ exchanger by interferon-gamma.
abstract: The present study evaluated the effect of interferon-gamma (IFN-gamma) on intestinal Na+/H+ exchange (NHE) activity and the intracellular signaling pathways set into motion after IFN-gamma receptor activation. Caco-2 cells express endogenous NHE1, NHE2 and NHE3 proteins, as detected by immunoblotting. Short- (0.5 h) and long- (24 h) term exposure of Caco-2 cells to IFN-gamma resulted in a concentration-dependent decrease in NHE activity. Inhibition of NHE activity by IFN-gamma was absent in cariporide-treated cells, but not in cells treated with S-3226. The long-term exposure to IFN-gamma was accompanied by a 20% increase in surface NHE1 abundance and no changes in total NHE1 abundance. Inhibition of Raf1, mitogen-activated protein kinase kinase (MAPKK/MEK) and p38 MAPK with, respectively, GW 5074, PD 98059 and SB 203580 and downregulation of protein kinase C (PKC) with phorbol-12,13-dibutyrate (100 nM for 24 h) prevented inhibition of NHE activity by IFN-gamma (0.5 and 24 h exposure). The signal transducer and activator transcription factor 1 (STAT1) inhibitor epigallocatechin-3-gallate (EGCG) prevented inhibition of NHE activity by long- but not the short-term treatment with IFN-gamma. Treatment with IFN-gamma activated phospho-p38 MAPK, this effect being detected as early as 1 h, persisting over 3 h and decreasing after 24 h. IFN-gamma produced a sustained action of phospho-STAT1 that was prevented by EGCG and partially attenuated by SB 203580 and insensitive to downregulation of PKC. In conclusion, short- and long-term inhibition of NHE1 activity by IFN-gamma involves a complex signaling pathway that includes PKC activation and STAT1 phosphorylation, respectively, but is not accompanied by downregulation of NHE1.
authors.affiliation: Faculty of Medicine, Institute of Pharmacology and Therapeutics, 4200-319 Porto, Portugal.
authors.forename: Fernando
authors.initials: F
authors.lastname: Magro
authors.forename: Sónia
authors.initials: S
authors.lastname: Fraga
authors.forename: Patrício
authors.initials: P
authors.lastname: Soares-da-Silva
mesh_terms: D018938:Caco-2 Cells; D004305:Dose-Response Relationship, Drug; D004789:Enzyme Activation; D015870:Gene Expression / Q000187:drug effects; D006801:Humans; D007371:Interferon-gamma / Q000494:pharmacology*; D007413:Intestinal Mucosa / Q000187:drug effects* / Q000378:metabolism*; D017471:Receptors, Interferon / Q000378:metabolism; D015398:Signal Transduction; D017923:Sodium-Hydrogen Exchangers / Q000037:antagonists & inhibitors* / Q000378:metabolism; D013997:Time Factors; D000096743:Interferon gamma Receptor
chemical_list: D007371:Interferon-gamma; D017471:Receptors, Interferon; D017923:Sodium-Hydrogen Exchangers; D000096743:Interferon gamma Receptor
references.citation: Am J Physiol. 1995 Feb;268(2 Pt 1):C283-96
references.pmid: 7864067
references.citation: Am J Physiol. 1999 Aug;277(2 Pt 1):G292-305
references.pmid: 10444443
references.citation: Clin Exp Immunol. 1995 Sep;101(3):428-35
references.pmid: 7664489
references.citation: J Biol Chem. 1995 Nov 17;270(46):27489-94
references.pmid: 7499206
references.citation: J Biol Chem. 1996 Mar 29;271(13):7460-4
references.pmid: 8631774
references.citation: J Biol Chem. 1996 Mar 22;271(12):6586-9
references.pmid: 8636072
references.citation: J Cell Sci. 1996 May;109 ( Pt 5):929-39
references.pmid: 8743940
references.citation: Am J Physiol. 1996 Oct;271(4 Pt 1):C1256-61
references.pmid: 8897832
references.citation: Physiol Rev. 1997 Jan;77(1):51-74
references.pmid: 9016300
references.citation: Immunol Today. 1997 May;18(5):209-11
references.pmid: 9153950
references.citation: EMBO J. 1997 Apr 15;16(8):1901-8
references.pmid: 9155016
references.citation: Am J Physiol. 1997 Aug;273(2 Pt 2):F289-99
references.pmid: 9277590
references.citation: Am J Physiol. 1997 Oct;273(4 Pt 1):G913-9
references.pmid: 9357835
references.citation: Semin Oncol. 1998 Feb;25(1 Suppl 1):14-22
references.pmid: 9482536
references.citation: J Pharmacol Exp Ther. 1998 May;285(2):869-75
references.pmid: 9580638
references.citation: Am J Physiol. 1998 May;274(5 Pt 1):C1261-72
references.pmid: 9612213
references.citation: J Biol Chem. 1998 Jul 24;273(30):18701-4
references.pmid: 9668040
references.citation: Pflugers Arch. 1998 Oct;436(5):797-800
references.pmid: 9716715
references.citation: Am J Physiol. 1998 Nov;275(5 Pt 1):G1085-93
references.pmid: 9815039
references.citation: Gut. 1999 Aug;45(2):191-8
references.pmid: 10403730
references.citation: Am J Physiol. 1999 Nov;277(5 Pt 2):F773-8
references.pmid: 10564242
references.citation: Bioorg Med Chem Lett. 2000 Feb 7;10(3):223-6
references.pmid: 10698440
references.citation: J Biol Chem. 2000 Dec 22;275(51):40120-7
references.pmid: 10969079
references.citation: Biochem J. 2000 Oct 1;351(Pt 1):95-105
references.pmid: 10998351
references.citation: Am J Physiol Cell Physiol. 2001 May;280(5):C1224-32
references.pmid: 11287336
references.citation: Endocr Rev. 2001 Apr;22(2):153-83
references.pmid: 11294822
references.citation: Gastroenterology. 2001 May;120(6):1393-403
references.pmid: 11313309
references.citation: FASEB J. 2001 May;15(7):1309-11
references.pmid: 11344123
references.citation: Am J Physiol Regul Integr Comp Physiol. 2001 Jul;281(1):R10-8
references.pmid: 11404273
references.citation: J Biol Chem. 2001 Dec 14;276(50):46701-6
references.pmid: 11585817
references.citation: Dig Dis Sci. 2002 Jan;47(1):216-24
references.pmid: 11837726
references.citation: J Biol Chem. 2002 Mar 1;277(9):7118-26
references.pmid: 11751911
references.citation: Am J Physiol Renal Physiol. 2002 Jun;282(6):F1084-96
references.pmid: 11997325
references.citation: J Immunol. 2002 Jun 15;168(12):5984-8
references.pmid: 12055203
references.citation: Am J Physiol Gastrointest Liver Physiol. 2002 Jul;283(1):G122-32
references.pmid: 12065299
references.citation: Am J Physiol Cell Physiol. 2002 Aug;283(2):C396-403
references.pmid: 12107048
references.citation: Cell Physiol Biochem. 2002;12(5-6):259-68
references.pmid: 12438762
references.citation: Br J Pharmacol. 2002 Dec;137(8):1305-13
references.pmid: 12466240
references.citation: N Engl J Med. 1991 Sep 26;325(13):928-37
references.pmid: 1881418
references.citation: J Biol Chem. 1991 Sep 25;266(27):18119-26
references.pmid: 1917946
references.citation: J Cell Sci. 1992 Jul;102 ( Pt 3):581-600
references.pmid: 1506435
references.citation: Immunology. 1993 Jan;78(1):127-31
references.pmid: 8436398
references.citation: J Immunol. 1993 Mar 15;150(6):2356-63
references.pmid: 8450217
references.citation: Infect Immun. 1994 Jul;62(7):2722-31
references.pmid: 7516311
references.citation: Am J Physiol. 1994 Aug;267(2 Pt 1):C402-10
references.pmid: 8074176
references.citation: Am J Physiol. 1994 Nov;267(5 Pt 1):C1398-404
references.pmid: 7526699
references.citation: Biochem J. 1995 Jan 15;305 ( Pt 2):425-31
references.pmid: 7832755
references.citation: Am J Physiol. 1995 Jan;268(1 Pt 1):C127-37
references.pmid: 7840140
references.citation: Can J Gastroenterol. 2003 Jan;17(1):31-6
references.pmid: 12560852
references.citation: Cell Physiol Biochem. 2004;14(1-2):91-100
references.pmid: 14976410
references.citation: Am J Physiol Gastrointest Liver Physiol. 2004 Aug;287(2):G370-8
references.pmid: 15075254
references.citation: Br J Pharmacol. 2004 Aug;142(8):1281-92
references.pmid: 15277314
references.citation: J Clin Invest. 1989 Feb;83(2):724-7
references.pmid: 2492310
references.citation: Gastroenterology. 1990 Jul;99(1):97-105
references.pmid: 2344946
references.citation: Am J Physiol. 1995 Jul;269(1 Pt 1):G1-11
references.pmid: 7631785