YAP Triggers the Wnt/β-catenin Signalling Pathway and Promotes Enterocyte Self-Renewal, Regeneration and Tumorigenesis After DSS-induced Injury

Cell Death Dis. 2018 Feb 2;9(2):153. doi: 10.1038/s41419-017-0244-8.

Abstract

Impaired epithelial regeneration is a crucial pathophysiological feature of ulcerative colitis (UC). Yes-associated protein (YAP1) appears to control cell proliferation and differentiation. In this study, we sought to identify the roles of YAP in intestinal epithelial cell (IEC) self-renewal, regeneration and tumorigenesis. We first observed that YAP was significantly reduced in 62.5% (45/72) of human UC tissues and it was dramatically enhanced during epithelial regeneration in a murine colitis model. Using lentiviral infection, we established a YAP-overexpression (YAPWT) mouse model. We then found that after tissue injury, YAPWT mice had increased epithelial cell self-renewal capacity and drastically restored intestinal crypt structure. Strikingly, these mice were more susceptible to colitis-associated cancer (CAC) in chemically induced carcinoma. Mechanistically, YAP and β-catenin showed increased nuclear co-localization during regeneration after inflammation. Overexpressing YAP significantly improved IEC 'wound-healing' ability and increased the expression of both β-catenin and the transcriptional targets of Wnt signalling Lgr5 and cyclin D1, whereas silencing β-catenin in YAPWT cells attenuated this effect. Remarkably, we observed that YAP could directly interact with β-catenin in the nucleus and formed a transcriptional YAP/β-catenin/TCF4 complex; Lgr5 and cyclin D1 were confirmed to be the target genes of this complex. In contrast, cancer cell proliferation and tumour development were suppressed by the phospho-mimetic YAP mutant. In summary, nuclear YAP-driven IEC proliferation could control epithelial regeneration after inflammation and may serve as a potential therapeutic target in UC. However, excessive YAP activation promoted CAC development.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adaptor Proteins, Signal Transducing / metabolism*
  • Adult
  • Animals
  • Carcinogenesis / metabolism*
  • Carcinogenesis / pathology*
  • Cell Cycle Proteins
  • Cell Line, Tumor
  • Cell Proliferation
  • Cell Self Renewal
  • Colitis / chemically induced
  • Colitis / pathology
  • Colitis, Ulcerative / metabolism
  • Colitis, Ulcerative / pathology
  • Dextran Sulfate
  • Disease Models, Animal
  • Enterocytes / metabolism*
  • Enterocytes / pathology*
  • Epithelial Cells / metabolism
  • Epithelium / metabolism
  • Female
  • Humans
  • Inflammation / pathology
  • Male
  • Mice, Inbred BALB C
  • Middle Aged
  • Phosphoproteins / metabolism*
  • Regeneration*
  • Transcription Factors
  • Wnt Signaling Pathway*

Substances

  • Adaptor Proteins, Signal Transducing
  • Cell Cycle Proteins
  • Phosphoproteins
  • Transcription Factors
  • YAP1 (Yes-associated) protein, human
  • Yap protein, mouse
  • Dextran Sulfate