Activation of the intrinsic fibroinflammatory program in adult pancreatic acinar cells triggered by Hippo signaling disruption

PLoS Biol. 2019 Sep 12;17(9):e3000418. doi: 10.1371/journal.pbio.3000418. eCollection 2019 Sep.

Abstract

Damaged acinar cells play a passive role in activating pancreatic stellate cells (PSCs) via recruitment of immune cells that subsequently activate PSCs. However, whether acinar cells directly contribute to PSC activation is unknown. Here, we report that the Hippo pathway, a well-known regulator of proliferation, is essential for suppression of expression of inflammation and fibrosis-associated genes in adult pancreatic acinar cells. Hippo inactivation in acinar cells induced yes-associated protein 1 (YAP1)/transcriptional coactivator with PDZ binding motif (TAZ)-dependent, irreversible fibrosis and inflammation, which was initiated by Hippo-mediated acinar-stromal communications and ameliorated by blocking YAP1/TAZ target connective tissue growth factor (CTGF). Hippo disruption promotes acinar cells to secrete fibroinflammatory factors and induce stromal activation, which precedes acinar proliferation and metaplasia. We found that Hippo disruption did not induce cell-autonomous proliferation but primed acinar cells to exogenous pro-proliferative stimuli, implying a well-orchestrated scenario in which Hippo signaling acts as an intrinsic link to coordinate fibroinflammatory response and proliferation for maintenance of the tissue integrity. Our findings suggest that the fibroinflammatory program in pancreatic acinar cells is suppressed under normal physiological conditions. While transient activation of inflammatory gene expression during tissue injury may contribute to the control of damage and tissue repair, its persistent activation may result in tissue fibrosis and failure of regeneration.

Publication types

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

MeSH terms

  • Acinar Cells / metabolism*
  • Acyltransferases
  • Adaptor Proteins, Signal Transducing / metabolism
  • Animals
  • Cell Cycle Proteins / metabolism
  • Fibrosis
  • Hippo Signaling Pathway
  • Mice
  • Pancreas / metabolism*
  • Pancreas / pathology
  • Pancreatic Stellate Cells / physiology
  • Pancreatitis / etiology*
  • Pancreatitis / metabolism
  • Pancreatitis / pathology
  • Protein Serine-Threonine Kinases / metabolism*
  • Signal Transduction
  • Transcription Factors / metabolism
  • YAP-Signaling Proteins

Substances

  • Adaptor Proteins, Signal Transducing
  • Cell Cycle Proteins
  • Transcription Factors
  • YAP-Signaling Proteins
  • Yap1 protein, mouse
  • Acyltransferases
  • tafazzin protein, mouse
  • Protein Serine-Threonine Kinases