miR-511-3p, embedded in the macrophage mannose receptor gene, contributes to intestinal inflammation

Mucosal Immunol. 2016 Jul;9(4):960-73. doi: 10.1038/mi.2015.113. Epub 2015 Nov 4.

Abstract

MiR-511-3p is embedded in intron 5 of the CD206/MRC1 gene Mrc1, expressed by macrophage and dendritic cell populations. CD206 and miR-511-3p expression are co-regulated, and their contribution to intestinal inflammation is unclear. We investigated their roles in intestinal inflammation in both mouse and human systems. Colons of CD206-deficient mice displayed normal numbers of monocytes, macrophage, and dendritic cells. In experimental colitis, CD206-deficient mice had attenuated inflammation compared with wild-type (WT) mice. However, neither a CD206 antagonist nor a blocking antibody reproduced this phenotype, suggesting that CD206 was not involved in this response. Macrophages isolated from CD206-deficient mice had reduced levels of miR-511-3p and Tlr4 compared with WT, which was associated with reduced pro-inflammatory cytokine production upon lipopolysaccharides (LPS) and fecal supernatant stimulation. Macrophages overexpressing miR-511-3p showed 50% increase of Tlr4 mRNA, whereas knockdown of miR-511-3p reduced Tlr4 mRNA levels by 60%, compared with scrambled microRNA (miRNA)-transduced cells. Response to anti-tumor necrosis factor (TNF) treatment has been associated with elevated macrophage CD206 expression in the mucosa. However, in colon biopsies no statistically significant change in miR-511-3p was detected. Taken together, our data show that miR-511-3p controls macrophage-mediated microbial responses and is involved in the regulation of intestinal inflammation.

MeSH terms

  • Animals
  • Cells, Cultured
  • Colitis / chemically induced
  • Colitis / immunology*
  • Colon / immunology*
  • Dextran Sulfate
  • Female
  • Gene Expression Regulation
  • Humans
  • Lipopolysaccharides / immunology
  • Macrophages / immunology*
  • Male
  • Membrane Glycoproteins / genetics*
  • Membrane Glycoproteins / metabolism
  • Mice
  • Mice, Inbred C57BL
  • Mice, Knockout
  • MicroRNAs / genetics*
  • Receptors, Cell Surface / genetics*
  • Receptors, Cell Surface / metabolism
  • Receptors, Immunologic
  • Toll-Like Receptor 4 / genetics
  • Toll-Like Receptor 4 / metabolism

Substances

  • Lipopolysaccharides
  • MIRN511 microRNA, human
  • MRC1 protein, mouse
  • Membrane Glycoproteins
  • MicroRNAs
  • Mirn511 microRNA, mouse
  • Receptors, Cell Surface
  • Receptors, Immunologic
  • Tlr4 protein, mouse
  • Toll-Like Receptor 4
  • Dextran Sulfate