Intestinal Epithelial Cell-Specific Deletion of PLD2 Alleviates DSS-Induced Colitis by Regulating Occludin

Sci Rep. 2017 May 8;7(1):1573. doi: 10.1038/s41598-017-01797-y.

Abstract

Ulcerative colitis is a multi-factorial disease involving a dysregulated immune response. Disruptions to the intestinal epithelial barrier and translocation of bacteria, resulting in inflammation, are common in colitis. The mechanisms underlying epithelial barrier dysfunction or regulation of tight junction proteins during disease progression of colitis have not been clearly elucidated. Increase in phospholipase D (PLD) activity is associated with disease severity in colitis animal models. However, the role of PLD2 in the maintenance of intestinal barrier integrity remains elusive. We have generated intestinal-specific Pld2 knockout mice (Pld2 IEC-KO) to investigate the mechanism of intestinal epithelial PLD2 in colitis. We show that the knockout of Pld2 confers protection against dextran sodium sulphate (DSS)-induced colitis in mice. Treatment with DSS induced the expression of PLD2 and downregulated occludin in colon epithelial cells. PLD2 was shown to mediate phosphorylation of occludin and induce its proteasomal degradation in a c-Src kinase-dependent pathway. Additionally, we have shown that treatment with an inhibitor of PLD2 can rescue mice from DSS-induced colitis. To our knowledge, this is the first report showing that PLD2 is pivotal in the regulation of the integrity of epithelial tight junctions and occludin turn over, thereby implicating it in the pathogenesis of colitis.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Colitis / chemically induced
  • Colitis / metabolism*
  • Colitis / pathology*
  • Dextran Sulfate
  • Dinitrofluorobenzene / analogs & derivatives
  • Down-Regulation
  • Epithelial Cells / metabolism*
  • Gene Deletion*
  • HT29 Cells
  • Humans
  • Intestines / pathology*
  • Mice, Inbred C57BL
  • Mice, Knockout
  • Models, Biological
  • Occludin / metabolism*
  • Organ Specificity
  • Phospholipase D / antagonists & inhibitors
  • Phospholipase D / genetics*
  • Phospholipase D / metabolism
  • Phosphorylation
  • Proteasome Endopeptidase Complex / metabolism
  • Proteolysis
  • src-Family Kinases / metabolism

Substances

  • Occludin
  • 2,4-dinitrofluorobenzene sulfonic acid
  • Dextran Sulfate
  • Dinitrofluorobenzene
  • src-Family Kinases
  • phospholipase D2
  • Phospholipase D
  • Proteasome Endopeptidase Complex