Ubc9 overexpression and SUMO1 deficiency blunt inflammation after intestinal ischemia/reperfusion

Lab Invest. 2018 Jun;98(6):799-813. doi: 10.1038/s41374-018-0035-6. Epub 2018 Feb 22.

Abstract

The intestinal epithelium constitutes a crucial defense to the potentially life-threatening effects of gut microbiota. However, due to a complex underlying vasculature, hypoperfusion and resultant tissue ischemia pose a particular risk to function and integrity of the epithelium. The small ubiquitin-like modifier (SUMO) conjugation pathway critically regulates adaptive responses to metabolic stress and is of particular significance in the gut, as inducible knockout of the SUMO-conjugating enzyme Ubc9 results in rapid intestinal epithelial disintegration. Here we analyzed the pattern of individual SUMO isoforms in intestinal epithelium and investigated their roles in intestinal ischemia/reperfusion (I/R) damage. Immunostaining revealed that epithelial SUMO2/3 expression was almost exclusively limited to crypt epithelial nuclei in unchallenged mice. However, intestinal I/R or overexpression of Ubc9 caused a remarkable enhancement of epithelial SUMO2/3 staining along the crypt-villus axis. Unexpectedly, a similar pattern was found in SUMO1 knockout mice. Ubc9 transgenic mice, but also SUMO1 knockout mice were protected from I/R injury as evidenced by better preserved barrier function and blunted inflammatory responses. PCR array analysis of microdissected villus-tip epithelia revealed a specific epithelial contribution to reduced inflammatory responses in Ubc9 transgenic mice, as key chemotactic signaling molecules such as IL17A were significantly downregulated. Together, our data indicate a critical role particularly of the SUMO2/3 isoforms in modulating responses to I/R and provide the first evidence that SUMO1 deletion activates a compensatory process that protects from ischemic damage.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, N.I.H., Intramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Chemokines / analysis
  • Intestinal Mucosa / blood supply*
  • Intestinal Mucosa / chemistry
  • Laser Capture Microdissection
  • Mice
  • Mice, Inbred C57BL
  • Mice, Knockout
  • Reperfusion Injury / prevention & control*
  • SUMO-1 Protein / deficiency
  • SUMO-1 Protein / physiology*
  • Small Ubiquitin-Related Modifier Proteins / analysis
  • Small Ubiquitin-Related Modifier Proteins / physiology
  • Ubiquitin-Conjugating Enzymes / genetics
  • Ubiquitin-Conjugating Enzymes / physiology*
  • Ubiquitins / analysis
  • Ubiquitins / physiology

Substances

  • Chemokines
  • SUMO-1 Protein
  • SUMO2 protein, mouse
  • Small Ubiquitin-Related Modifier Proteins
  • Sumo3 protein, mouse
  • Ubiquitins
  • Ubiquitin-Conjugating Enzymes
  • ubiquitin-conjugating enzyme UBC9