Proprotein convertase 1/3 (PC1/3) in the rat alveolar macrophage cell line NR8383: localization, trafficking and effects on cytokine secretion

PLoS One. 2013 Apr 24;8(4):e61557. doi: 10.1371/journal.pone.0061557. Print 2013.

Abstract

The proprotein convertase 1/3 (PC1/3) is an important post-translational processing enzyme for the activation of precursor proteins within the regulated secretory pathway. Well characterized for its role in the neural and endocrine systems, we recently reported an unconventional role of PC1/3 as a modulator of the Toll-like receptor innate immune response. There are only a few reports that have studied PC1/3 expression in macrophages, and more investigation is needed to better characterize its function. These studies would greatly benefit from model cell lines. Our study aims to identify and characterize PC1/3 in a relevant model macrophage cell line and to determine the links between PC1/3 and innate immune cellular responses. We describe the rat alveolar cell line, NR8383, as expressing PC1/3 and the most common Toll-like receptors. In NR8383 cells, PC1/3 is localized at the Trans-Golgi network and traffics to lysosome related vesicles upon lipopolysaccharide stimulation. Moreover, we report the co-localization of PC1/3 and Toll-like receptor 4 upon lipopolysaccharide stimulation. Down regulation of PC1/3 by shRNA produce a similar phenotype in NR8383 to what we previously reported in isolated peritoneal macrophages. PC1/3 shRNA induced changes in the cellular organization and expression of the specific trafficking regulator RAB GTPase. As a consequence, NR8383 down-regulated for PC1/3, present an abnormal cytokine secretion profile. We conclude that the NR8383 cell line represents a good model to study PC1/3 in macrophages and we present PC1/3 as an important regulator of vesicle trafficking and secretion in macrophages.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cell Line
  • Cytokines / metabolism
  • Gene Expression
  • Gene Expression Regulation
  • Lipopolysaccharides / pharmacology
  • Macrophages, Alveolar / metabolism*
  • Macrophages, Alveolar / ultrastructure
  • Proprotein Convertase 1 / genetics
  • Proprotein Convertase 1 / metabolism*
  • Protein Processing, Post-Translational
  • Protein Transport / drug effects
  • RNA Interference
  • Rats
  • Toll-Like Receptors / genetics
  • Toll-Like Receptors / metabolism
  • Transport Vesicles / metabolism

Substances

  • Cytokines
  • Lipopolysaccharides
  • Toll-Like Receptors
  • Proprotein Convertase 1

Grants and funding

This work was supported by the Canadian Institutes of Health Research (CIHR to Robert Day), the Ministère du Développement Économique de l’Innovation et de l’Exportation (MDEIE to Robert Day) and the Fond de recherche du Québec-Santé (FRQ-S to Robert day). Additional support was received from grants from Ministère de L’Education Nationale, de L’Enseignement Supérieur (to Michel Salzet) and the CNRS (to Michel Salzet). Robert Day is a member of the Centre de Recherche Clinique Etienne-LeBel (Sherbrooke, Qc, Canada). Hugo Gagnon holds a bursary from CNRS and received the Frontenac mobility grant for a joint thesis (Franco-Quebec) from FQRNT and the French consulate. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.