The role of the secretin/secretin receptor axis in inflammatory cholangiocyte communication via extracellular vesicles

Sci Rep. 2017 Sep 11;7(1):11183. doi: 10.1038/s41598-017-10694-3.

Abstract

Small and large intrahepatic bile ducts consist of small and large cholangiocytes, respectively, and these cholangiocytes have different morphology and functions. The gastrointestinal peptide hormone, secretin (SCT) that binds to secretin receptor (SR), is a key mediator in cholangiocyte pathophysiology. Extracellular vesicles (EVs) are membrane-bound vesicles and cell-cell EV communication is recognized as an important factor in liver pathology, although EV communication between cholangiocytes is not identified to date. Cholangiocytes secrete proinflammatory cytokines during bacterial infection leading to biliary inflammation and hyperplasia. We demonstrate that cholangiocytes stimulated with lipopolysaccharide (LPS), which is a membrane component of gram-negative bacteria, secrete more EVs than cholangiocytes incubated with vehicle. These LPS-derived EVs induce inflammatory responses in other cholangiocytes including elevated cytokine production and cell proliferation. Large but not small cholangiocytes show inflammatory responses against large but not small cholangiocyte-derived EVs. Large cholangiocytes with knocked down either SCT or SR by short hairpin RNAs show reduced EV secretion during LPS stimulation, and EVs isolated from SCT or SR knocked down cholangiocytes fail to induce inflammatory reactions in control large cholangiocytes. This study identifies cholangiocyte EV communication during LPS stimulation, and demonstrates that the SCT/SR axis may be important for this event.

Publication types

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

MeSH terms

  • Bile Ducts / cytology*
  • Cell Communication*
  • Cell Line
  • Cell Proliferation
  • Cytokines / metabolism
  • Epithelial Cells / drug effects
  • Epithelial Cells / physiology*
  • Extracellular Vesicles / metabolism*
  • Hormones / metabolism*
  • Humans
  • Lipopolysaccharides / metabolism
  • Receptors, G-Protein-Coupled / metabolism*
  • Receptors, Gastrointestinal Hormone / metabolism*
  • Secretin / metabolism*

Substances

  • Cytokines
  • Hormones
  • Lipopolysaccharides
  • Receptors, G-Protein-Coupled
  • Receptors, Gastrointestinal Hormone
  • secretin receptor
  • Secretin