title: Proteomic analysis of the winter-protected phenotype of hibernating ground squirrel intestine.
abstract: The intestine of hibernating ground squirrels is protected against damage by ischemia-reperfusion (I/R) injury. This resistance does not depend on the low body temperature of torpor; rather, it is exhibited during natural interbout arousals that periodically return hibernating animals to euthermia. Here we use fluorescence two-dimensional difference gel electrophoresis (DIGE) to identify protein spot differences in intestines of 13-lined ground squirrels in the sensitive and protected phases of the circannual hibernation cycle, comparing sham-treated control animals with those exposed to I/R. Protein spot differences distinguished the sham-treated summer and hibernating samples, as well as the response to I/R between summer and hibernating intestines. The majority of protein changes among these groups were attributed to a seasonal difference between summer and winter hibernators. Many of the protein spots that differed were unambiguously identified by high-pressure liquid chromatography followed by tandem mass spectrometry of their constituent peptides. Western blot analysis confirmed significant upregulation for three of the proteins, albumin, apolipoprotein A-I, and ubiquitin hydrolase L1, that were identified in the DIGE analysis as increased in sham-treated hibernating squirrels compared with sham-treated summer squirrels. This study identifies several candidate proteins that may contribute to hibernation-induced protection of the gut during natural torpor-arousal cycles and experimental I/R injury. It also reveals the importance of enterocyte maturation in defining the hibernating gut proteome and the role of changing cell populations for the differences between sham and I/R-treated summer animals.
authors.affiliation: Department of Cell and Developmental Biology, University of Colorado School of Medicine, Aurora, Colorado 80045, USA. sandy.martin@uchsc.edu
authors.forename: Sandra L
authors.initials: SL
authors.lastname: Martin
authors.forename: L Elaine
authors.initials: LE
authors.lastname: Epperson
authors.forename: James C
authors.initials: JC
authors.lastname: Rose
authors.forename: Courtney C
authors.initials: CC
authors.lastname: Kurtz
authors.forename: Cécile
authors.initials: C
authors.lastname: Ané
authors.forename: Hannah V
authors.initials: HV
authors.lastname: Carey
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D020869:Gene Expression Profiling; D006605:Hibernation / Q000502:physiology*; D007410:Intestinal Diseases / Q000473:pathology / Q000662:veterinary; D007413:Intestinal Mucosa / Q000378:metabolism*; D007422:Intestines / Q000473:pathology; D010641:Phenotype; D040901:Proteomics; D015427:Reperfusion Injury / Q000473:pathology / Q000517:prevention & control; D012589:Sciuridae / Q000502:physiology*; D012621:Seasons