Double-stranded DNA activates glomerular endothelial cells and enhances albumin permeability via a toll-like receptor-independent cytosolic DNA recognition pathway

Am J Pathol. 2009 Nov;175(5):1896-904. doi: 10.2353/ajpath.2009.090182. Epub 2009 Oct 15.

Abstract

Viral DNA induces potent antiviral immunity by activating dendritic cells; however, the mechanism governing viral DNA-mediated triggering or aggravation of glomerulonephritis is unknown. Glomerular endothelial cells (GEnCs) do not express toll-like receptor (TLR)9, the only DNA-specific TLR. We therefore hypothesized that DNA could activate GEnCs via the recently discovered TLR-independent viral DNA recognition pathway. Indeed, double-stranded non-CpG (B-) DNA activated GEnCs to produce interleukin-6, CCL5/RANTES, CCL2/MCP-1, CXCL10/IP10, interferon (IFN)-alpha, and IFN-beta when cationic lipids facilitated intracellular DNA uptake. This cytokine production was inhibited by chlorpromazine, suggesting that clathrin-dependent endocytosis is required for B-DNA entry. However, chloroquine and MyD88 inhibition did not affect GEnC activation, suggesting TLR-independent DNA recognition. In addition, IFN-beta activated cytokine and chemokine mRNA expression, although only CXCL10/IP10 was induced at the protein level, and type I IFN did not activate GEnC in an autocrine-paracrine auto-activation loop. B-DNA complexes induced intercellular adhesion molecule-1 expression at the GEnC surface and increased intercellular adhesion molecule-1-dependent leukocyte adhesion and microvascular extravasation in vivo. Furthermore, B-DNA complexes increased albumin permeability of GEnC monolayers in culture or microvascular dextran leakage in vivo. In addition, B-DNA complexes impaired GEnC proliferation. Thus, complexed B-DNA activates GEnC to produce cytokines, chemokines, and type I IFNs, increases leukocyte adhesion and microvascular permeability, and reduces GEnC proliferation via a MyD88-independent cytosolic DNA recognition pathway. This innate antiviral response program suggests a novel pathomechanism regulating DNA virus-mediated induction or aggravation of glomerulonephritis.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Capillary Permeability / physiology*
  • Cell Adhesion
  • Cell Communication / physiology
  • Chemokines / immunology
  • Cytokines / immunology
  • DNA / immunology*
  • DNA, Viral / immunology
  • Endocytosis / physiology
  • Endosomes / metabolism
  • Endothelial Cells / cytology
  • Endothelial Cells / immunology
  • Endothelial Cells / physiology*
  • Intercellular Adhesion Molecule-1 / metabolism
  • Interferon Type I / immunology
  • Kidney Glomerulus* / cytology
  • Kidney Glomerulus* / metabolism
  • Leukocytes / cytology
  • Leukocytes / metabolism
  • Mice
  • Myeloid Differentiation Factor 88 / metabolism
  • RNA Interference
  • Serum Albumin / metabolism*
  • Signal Transduction / physiology*
  • Toll-Like Receptors / genetics
  • Toll-Like Receptors / immunology*

Substances

  • Chemokines
  • Cytokines
  • DNA, Viral
  • Interferon Type I
  • Myeloid Differentiation Factor 88
  • Serum Albumin
  • Toll-Like Receptors
  • Intercellular Adhesion Molecule-1
  • DNA