MCP-1 targeting inhibits muscularis macrophage recruitment and intestinal smooth muscle dysfunction in colonic inflammation

Am J Physiol Cell Physiol. 2008 Feb;294(2):C391-401. doi: 10.1152/ajpcell.00056.2007. Epub 2007 Oct 31.

Abstract

Upregulation of muscularis macrophage numbers and activities plays an important role in the intestinal dysmotility associated with intestinal inflammation. The present study aimed to clarify changes in population dynamics of intestinal muscularis macrophages during colonic inflammation and to test possible inhibitory actions of agents targeting monocyte chemoattractant protein-1 (MCP-1) on muscularis macrophage dynamics and motility disorder in the colonic inflammation elicited by 2,4,6-trinitrobenzene sulfonic acid. In the inflamed muscle layer, ED1 antibody-positive monocytes and monocyte-derived macrophages were increased, followed by increasing resident macrophages positively staining for ED2 antibody. Initiation of the ED1-positive macrophage dynamic is associated with MCP-1 mRNA expression. MCP-1 was expressed in both ED1- and ED2-positive macrophages after inflammation. Electromicroscopic analysis revealed that the cell-division phase of muscularis macrophages was seen only in the early stages of inflammation. In addition, ED1 and ED2 double-positive macrophages can be detected during inflammation. Treatment with dominant negative MCP-1 or neutralizing MCP-1 antibodies markedly inhibited numbers of both ED1- and ED2-positive macrophages. Inflammation-mediated dysmotility was partially recovered by treatment with neutralizing MCP-1 antibodies. These results suggest that the inflamed muscle layer is initially infiltrated by monocytes, which then differentiate and develop into muscularis-resident macrophages. These macrophages express MCP-1 for further recruitment of monocytes. MCP-1 may be one potential therapeutic target for inhibiting intestinal motility disorders in gut inflammation.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antibodies / pharmacology
  • Cell Differentiation / drug effects
  • Cell Differentiation / immunology
  • Chemokine CCL2 / genetics
  • Chemokine CCL2 / immunology*
  • Chemokine CCL2 / metabolism
  • Chemotaxis, Leukocyte / immunology*
  • Colitis / chemically induced
  • Colitis / immunology*
  • Colitis / physiopathology
  • Fluorescent Antibody Technique
  • Inflammation Mediators / pharmacology
  • Macrophages / immunology*
  • Male
  • Microscopy, Electron, Transmission
  • Monocytes / drug effects
  • Monocytes / immunology
  • Muscle, Smooth / immunology*
  • Muscle, Smooth / pathology
  • Muscle, Smooth / physiopathology
  • Myenteric Plexus / immunology
  • Myenteric Plexus / pathology
  • Myenteric Plexus / physiopathology
  • RNA, Messenger / metabolism
  • Rats
  • Rats, Sprague-Dawley
  • Trinitrobenzenesulfonic Acid / pharmacology

Substances

  • Antibodies
  • Ccl2 protein, rat
  • Chemokine CCL2
  • Inflammation Mediators
  • RNA, Messenger
  • Trinitrobenzenesulfonic Acid