Abstract
Background & AimsIntestinal ischemia-reperfusion injury is a serious and life-threatening condition. A better understanding of molecular mechanisms related to intestinal ischemia-reperfusion injury in human beings is imperative to find therapeutic targets and improve patient outcome.MethodsFirst, the in vivo dynamic modulation of mucosal gene expression of the ischemia-reperfusion–injured human small intestine was studied. Based on functional enrichment analysis of the changing transcriptome, one of the predominantly regulated pathways was selected for further investigation in an in vitro human intestinal organoid model.ResultsIschemia-reperfusion massively changed the transcriptional landscape of the human small intestine. Functional enrichment analysis based on gene ontology and pathways pointed to the response to unfolded protein as a predominantly regulated process. In addition, regulatory network analysis identified hypoxia-inducing factor 1A as one of the key mediators of ischemia-reperfusion–induced changes, including the unfolded protein response (UPR). Differential expression of genes involved in the UPR was confirmed using quantitative polymerase chain reaction analysis. Electron microscopy showed signs of endoplasmic reticulum stress. Collectively, these findings point to a critical role for unfolded protein stress in intestinal ischemia-reperfusion injury in human beings. In a human intestinal organoid model exposed to hypoxia-reoxygenation, attenuation of UPR activation with integrated stress response inhibitor strongly reduced pro-apoptotic activating transcription factor 4 (ATF4)-CCAAT/enhancer-binding protein homologous protein (CHOP) signaling.ConclusionsTranscriptome analysis showed a crucial role for unfolded protein stress in the response to ischemia-reperfusion in human small intestine. UPR inhibition during hypoxia-reoxygenation in an intestinal organoid model suggests that downstream protein kinase R-like ER kinase (PERK) signaling may be a promising target to reduce intestinal ischemia-reperfusion injury. Microarray data are available in GEO (https://www.ncbi.nlm.nih.gov/gds, accession number GSE37013).
Highlights
BACKGROUND & AIMSIntestinal ischemia-reperfusion injury is a serious and life-threatening condition
In a human intestinal organoid model exposed to hypoxia-reoxygenation, attenuation of unfolded protein response (UPR) activation with integrated stress response inhibitor strongly reduced pro-apoptotic activating transcription factor 4 (ATF4)CCAAT/enhancer-binding protein homologous protein (CHOP) signaling
Transcriptome analysis showed a crucial role for unfolded protein stress in the response to ischemiareperfusion in human small intestine
Summary
The in vivo dynamic modulation of mucosal gene expression of the ischemia-reperfusion–injured human small intestine was studied. A variable length of jejunum routinely was resected in continuity with the head of the pancreas and duodenum as part of the surgical procedure. One third (2 cm) of the isolated ischemic jejunum was resected using a linear cutting stapler (0R). Clamps were removed to allow reperfusion, which was confirmed by regaining normal pink color and restoration of gut motility. Another segment of the isolated jejunum (2 cm) was resected after 30R. A 2-cm segment of jejunum, which was not subjected to ischemia-reperfusion but underwent similar surgical handling as the isolated part of the jejunum, was resected and served as internal control tissue (C). Patients with obstructive jaundice underwent a stent procedure before surgery. All patients had normal bile flow at the time of surgery
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