Regulation of macrophage motility by the water channel aquaporin-1: crucial role of M0/M2 phenotype switch

PLoS One. 2015 Feb 26;10(2):e0117398. doi: 10.1371/journal.pone.0117398. eCollection 2015.

Abstract

The water channel aquaporin-1 (AQP1) promotes migration of many cell types. Although AQP1 is expressed in macrophages, its potential role in macrophage motility, particularly in relation with phenotype polarization, remains unknown. We here addressed these issues in peritoneal macrophages isolated from AQP1-deficient mice, either undifferentiated (M0) or stimulated with LPS to orientate towards pro-inflammatory phenotype (classical macrophage activation; M1). In non-stimulated macrophages, ablation of AQP1 (like inhibition by HgCl2) increased by 2-3 fold spontaneous migration in a Src/PI3K/Rac-dependent manner. This correlated with cell elongation and formation of lamellipodia/ruffles, resulting in membrane lipid and F4/80 recruitment to the leading edge. This indicated that AQP1 normally suppresses migration of resting macrophages, as opposed to other cell types. Resting Aqp1-/- macrophages exhibited CD206 redistribution into ruffles and increased arginase activity like IL4/IL13 (alternative macrophage activation; M2), indicating a M0-M2 shift. In contrast, upon M1 orientation by LPS in vitro or peritoneal inflammation in vivo, migration of Aqp1-/- macrophages was reduced. Taken together, these data indicate that AQP1 oppositely regulates macrophage migration, depending on stimulation or not by LPS, and that macrophage phenotypic and migratory changes may be regulated independently of external cues.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Aquaporin 1 / genetics
  • Aquaporin 1 / metabolism*
  • Arginase / metabolism
  • Cell Movement*
  • Interleukins / genetics
  • Interleukins / metabolism
  • Lectins, C-Type / genetics
  • Lectins, C-Type / metabolism
  • Macrophage Activation*
  • Macrophages, Peritoneal / immunology
  • Macrophages, Peritoneal / metabolism*
  • Macrophages, Peritoneal / physiology
  • Mannose Receptor
  • Mannose-Binding Lectins / genetics
  • Mannose-Binding Lectins / metabolism
  • Mice
  • Mice, Inbred C57BL
  • Phosphatidylinositol 3-Kinases / metabolism
  • Receptors, Cell Surface / genetics
  • Receptors, Cell Surface / metabolism
  • rac GTP-Binding Proteins / metabolism
  • src-Family Kinases / metabolism

Substances

  • Aqp1 protein, mouse
  • Interleukins
  • Lectins, C-Type
  • Mannose Receptor
  • Mannose-Binding Lectins
  • Receptors, Cell Surface
  • Aquaporin 1
  • src-Family Kinases
  • Arginase
  • rac GTP-Binding Proteins

Grants and funding

This work was supported by grants from UCL, F.R.S.-FNRS, Région wallonne, Région bruxelloise, Loterie nationale, ARC, (Actions de Recherche concertée), IUAP (The InterUniversity Attraction Poles IUAP (all Belgium), Baxter Healthcare (Extramural Grant Program) and the Sumitomo Life Social Welfare Services Foundation. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.