Interleukin-11-induced heat shock protein 25 confers intestinal epithelial-specific cytoprotection from oxidant stress.
OBJECTIVE
The mechanisms of interleukin-11 (IL-11) cytoprotection in intestinal epithelial injury are largely unknown. IL-11 protects barrier integrity during oxidant stress, a common endpoint of numerous types of intestinal injury including ischemia and immune-mediated inflammation. Because heat shock proteins (hsp) are cytoprotective in intestinal epithelia, we hypothesized that IL-11-conferred cytoprotection is mediated by inducible hsps.


METHODS
IL-11 receptor (IL-11R) activation was determined using phospho-specific antibodies to STAT3. IL-11 induction of hsp72 and hsp25 was determined by immunoblot in IEC-18 crypt and young adult mouse colon colonic epithelial cells. Epithelial resistance to oxidant injury by monochloramine was determined by (51)Cr release. Stable hsp anti-sense IEC-18 cell clones were obtained by electroporation and hygromycin B selection. The IL-11 effect on hsp25 distribution was characterized by analysis of Triton x-100 insoluble fractions, 2-D isoelectric focusing gels, and confocal microscopy.


RESULTS
IL-11R signaling was detected in all cells under study. IL-11 induces hsp25 in an intestinal epithelial-specific manner that significantly preserves cellular viability in the presence of monochloramine. This effect was significantly reversed in intestinal epithelia stably expressing anti-sense to hsp25. IL-11 induced a shift of hsp25 to Triton x-100 insoluble fractions containing cytoskeletal elements, which was not associated with altered hsp25 phosphorylation. The shift was not paralleled by increased hsp25 co-localization with F-actin by confocal microscopy.


CONCLUSIONS
The induction of hsp25 by IL-11 confers epithelial-specific cytoprotection that is independent of phosphorylation-dependent co-localization of hsp25 to F-actin, thereby contributing to the protective effects of IL-11 in models of intestinal epithelial injury.
Ropeleski
Mark J
MJ
Department of Medicine, University of Chicago, Illinois 60637, USA.
Tang
Jun
J
Walsh-Reitz
Margaret M
MM
Musch
Mark W
MW
Chang
Eugene B
EB
D016475:3T3 Cells; D000199:Actins / Q000378:metabolism; D000818:Animals; D000906:Antibodies; D002460:Cell Line; D002700:Chloramines / Q000494:pharmacology; D003599:Cytoskeleton / Q000378:metabolism; D016373:DNA, Antisense / Q000235:genetics; D003902:Detergents; D004305:Dose-Response Relationship, Drug; D055551:HSP27 Heat-Shock Proteins; D006360:Heat-Shock Proteins; D018869:Heat-Shock Response / Q000502:physiology; D015151:Immunoblotting; D017370:Interleukin-11 / Q000494:pharmacology*; D053703:Interleukin-11 Receptor alpha Subunit; D007413:Intestinal Mucosa / Q000166:cytology / Q000378:metabolism*; D051379:Mice; D018832:Molecular Chaperones; D009363:Neoplasm Proteins / Q000235:genetics* / Q000276:immunology; D017830:Octoxynol; D018384:Oxidative Stress / Q000187:drug effects* / Q000502:physiology; D010766:Phosphorylation; D051381:Rats; D018123:Receptors, Interleukin / Q000235:genetics; D053702:Receptors, Interleukin-11; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology; D012995:Solubility; D014162:Transfection
D000199:Actins; D000906:Antibodies; D002700:Chloramines; D016373:DNA, Antisense; D003902:Detergents; D055551:HSP27 Heat-Shock Proteins; D006360:Heat-Shock Proteins; C486113:Hsbp1 protein, mouse; C486114:Hspb1 protein, rat; C508429:Il11ra1 protein, mouse; C508430:Il11ra1 protein, rat; D017370:Interleukin-11; D053703:Interleukin-11 Receptor alpha Subunit; D018832:Molecular Chaperones; D009363:Neoplasm Proteins; D018123:Receptors, Interleukin; D053702:Receptors, Interleukin-11; D017830:Octoxynol; C030816:chloramine