dsRNA activation of endothelin-1 and markers of vascular activation in endothelial cells and fibroblasts

Ann Rheum Dis. 2011 Mar;70(3):544-50. doi: 10.1136/ard.2010.132464. Epub 2010 Nov 10.

Abstract

Background: In patients with systemic sclerosis (SSc), the relationship between innate immune activation, represented by increased expression of interferon (IFN)-regulated genes, and vascular injury/activation, manifest by increased endothelin-1 (ET-1), endothelin converting enzyme-1 (ECE1) and intercellular adhesion molecule-1, is uncertain.

Objective: To investigate the potential roles of innate immune ligands in both these pathogenic pathways.

Methods: The effect of known Toll-like receptor (TLR) ligands was tested in vitro on dermal microvascular and pulmonary arterial endothelial cells, and on dermal fibroblasts cultured from healthy controls and patients with SSc. To test the effect of double-stranded RNA (dsRNA) on vascular activation/injury in vivo, polyinosinic/polycytidylic acid (poly(I:C)) was administered continuously over 7 days by subcutaneous osmotic pump.

Results: dsRNA/poly(I:C), but not other TLR ligands, highly stimulated ET-1 protein and mRNA (EDN1), as well as intercellular adhesion molecule-1 (ICAM-1) and IFN-regulated MX2, by endothelial cells and dermal fibroblasts. Poly(I:C) induced EDN1, ECE1, and ICAM-1 mRNA expression in poly(I:C) treated skin. Poly(I:C)-induced EDN1, ECE1 and MX2 was not blocked in mice with the type I IFN receptor deleted. However, poly(I:C)-induced EDN1 and ECE1, but not poly(I:C)-induced ICAM-1 expression was blocked in mice with the TLR3 signalling protein TRIF/TICAM-1 deleted.

Conclusion: Together these data show that the dsRNA can regulate genes associated with vascular activation, as seen in SSc, that type I IFNs do not mediate these effects, and that EDN1 and ECE1 but not ICAM-1 activation is mediated by TLR3.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cells, Cultured
  • Endothelial Cells / drug effects
  • Endothelial Cells / metabolism
  • Endothelin-1 / biosynthesis*
  • Endothelin-1 / genetics
  • Endothelium, Vascular / drug effects
  • Endothelium, Vascular / metabolism
  • Fibroblasts / metabolism*
  • GTP-Binding Proteins / biosynthesis
  • GTP-Binding Proteins / genetics
  • Gene Expression Regulation
  • Humans
  • Immunity, Innate
  • Ligands
  • Mice
  • Mice, Inbred C57BL
  • Myxovirus Resistance Proteins
  • Poly I-C / pharmacology
  • Pulmonary Artery / drug effects
  • Pulmonary Artery / metabolism
  • RNA, Double-Stranded / genetics
  • RNA, Messenger / genetics
  • Scleroderma, Systemic / genetics
  • Scleroderma, Systemic / immunology
  • Scleroderma, Systemic / metabolism*
  • Skin / metabolism
  • Toll-Like Receptor 3 / metabolism

Substances

  • Endothelin-1
  • Ligands
  • Mx2 protein, mouse
  • Myxovirus Resistance Proteins
  • RNA, Double-Stranded
  • RNA, Messenger
  • TLR3 protein, human
  • Toll-Like Receptor 3
  • GTP-Binding Proteins
  • Poly I-C