Helminth induced suppression of macrophage activation is correlated with inhibition of calcium channel activity

PLoS One. 2014 Jul 11;9(7):e101023. doi: 10.1371/journal.pone.0101023. eCollection 2014.

Abstract

Helminth parasites cause persistent infections in humans and yet many infected individuals are asymptomatic. Neurocysticercosis (NCC), a disease of the central nervous system (CNS) caused by the cestode Taenia solium, has a long asymptomatic phase correlated with an absence of brain inflammation. However, the mechanisms of immune suppression remain poorly understood. Here we report that murine NCC displays a lack of cell surface maturation markers in infiltrating myeloid cells. Furthermore, soluble parasite ligands (PL) failed to induce maturation of macrophages, and inhibited TLR-induced inflammatory cytokine production. Importantly, PL treatment abolished both LPS and thapsigargin-induced store operated Ca2+ entry (SOCE). Moreover, electrophysiological recordings demonstrated PL-mediated inhibition of LPS or Tg-induced currents that were TRPC1-dependent. Concomitantly STIM1-TRPC1 complex was also impaired that was essential for SOCE and sustained Ca2+ entry. Likewise loss of SOCE due to PL further inhibited NFkB activation. Overall, our results indicate that the negative regulation of agonist induced Ca2+ signaling pathway by parasite ligands may be a novel immune suppressive mechanism to block the initiation of the inflammatory response associated with helminth infections.

Publication types

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

MeSH terms

  • Animals
  • Blotting, Western
  • Calcium Channels / metabolism*
  • Electrophysiology
  • Female
  • Fluorescent Antibody Technique
  • Helminths / pathogenicity*
  • Immunoprecipitation
  • Macrophage Activation / physiology*
  • Mice
  • Mice, Inbred BALB C
  • Neurocysticercosis / metabolism*
  • Real-Time Polymerase Chain Reaction
  • Stromal Interaction Molecule 1
  • TRPC Cation Channels / metabolism

Substances

  • Calcium Channels
  • Stim1 protein, mouse
  • Stromal Interaction Molecule 1
  • TRPC Cation Channels
  • transient receptor potential cation channel, subfamily C, member 1