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Fibronectin stabilization and Fibronectin‐Integrin signaling via MAPK are required in L‐Glutamine‐mediated protection against gut injury
Author(s) -
Niederlechner Stefanie,
Klawitter Jelena,
Baird Christine,
Kallweit Alyssa,
Christians Uwe,
Wischmeyer Paul
Publication year - 2012
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.26.1_supplement.1064.13
Subject(s) - glutamine , fibronectin , integrin , phosphorylation , western blot , heat shock protein , chemistry , microbiology and biotechnology , hsp70 , biology , biochemistry , cell , amino acid , gene
We assessed if Fibronectin (FN) expression and FN‐Integrin pathways, which play a protective role after gut injury, are involved in L‐Glutamine's (GLN) protective mechanism in the intestine after heat stress (HS). IEC‐6 cells were treated with 0mM or 10mM GLN with or without FN siRNA (20nM), integrin inhibitor GRGDSP (50μM), control peptide GRGESP (50μM), or ERK1/2 inhibitor PD98059 (50μM). Cell survival was measured via MTS assay 24h post‐HS (44ºCx50min). Total ERK1/2 and HSF‐1, [T(P)202/Y(P)204]ERK1/2, [S(P)303]HSF‐1, HSP32, HSP70, FN, cleaved caspase‐3 and PARP levels were determined via Western blot, and GLN‐transport via LC‐MS/MS after non‐lethal HS (43ºCx45min). GLN prevented the decrease in FN levels after HS and GLN's protection decreased after FN siRNA treatment (p<0.05; n=3). Thus, GRGDSP did not affect GLN transport into the cells (p<0.05; n=3), GRGDSP and PD98059 attenuated GLN‐mediated protection, shown by MTS, cleaved caspase‐3 and PARP levels (p<0.05; n=5). GRGDSP abolished GLN‐mediated Erk1/2 activation after HS (p<0.05; n=4). GLN activated HSF‐1 by attenuating its’ phosphorylation at serine 303 (p<0.05; n=3), but HS, HS+GRGDSP+GLN and HS+PD98059+GLN repressed HSF‐1 by its’ phosphorylation (p<0.05; n=3). GLN‐mediated increases in HSP70 and HSP32 were attenuated by GRGDSP after HS (p<0.05; n=4). FN stabilization and FN‐Integrin signaling via MAPK by GLN seem to be vital after gut injury.