The Protein Kinase Double-Stranded RNA-Dependent (PKR) Enhances Protection against Disease Cause by a Non-Viral Pathogen

Pauline Sebby Ogolla, Jose Andres C Portillo, Christine L. White, Krupen Patel, Bruce Lamb, Ganes C. Sen, Carlos S. Subauste

Research output: Contribution to journalArticle

20 Citations (Scopus)

Abstract

PKR is well characterized for its function in antiviral immunity. Using Toxoplasma gondii, we examined if PKR promotes resistance to disease caused by a non-viral pathogen. PKR-/- mice infected with T. gondii exhibited higher parasite load and worsened histopathology in the eye and brain compared to wild-type controls. Susceptibility to toxoplasmosis was not due to defective expression of IFN-γ, TNF-α, NOS2 or IL-6 in the retina and brain, differences in IL-10 expression in these organs or to impaired induction of T. gondii-reactive T cells. While macrophages/microglia with defective PKR signaling exhibited unimpaired anti-T. gondii activity in response to IFN-γ/TNF-α, these cells were unable to kill the parasite in response to CD40 stimulation. The TRAF6 binding site of CD40, but not the TRAF2,3 binding sites, was required for PKR phosphorylation in response to CD40 ligation in macrophages. TRAF6 co-immunoprecipitated with PKR upon CD40 ligation. TRAF6-PKR interaction appeared to be indirect, since TRAF6 co-immunoprecipitated with TRAF2 and TRAF2 co-immunoprecipitated with PKR, and deficiency of TRAF2 inhibited TRAF6-PKR co-immunoprecipitation as well as PKR phosphorylation induced by CD40 ligation. PKR was required for stimulation of autophagy, accumulation the autophagy molecule LC3 around the parasite, vacuole-lysosomal fusion and killing of T. gondii in CD40-activated macrophages and microglia. Thus, our findings identified PKR as a mediator of anti-microbial activity and promoter of protection against disease caused by a non-viral pathogen, revealed that PKR is activated by CD40 via TRAF6 and TRAF2, and positioned PKR as a link between CD40-TRAF signaling and stimulation of the autophagy pathway.

Original languageEnglish (US)
Article numbere1003557
JournalPLoS Pathogens
Volume9
Issue number8
DOIs
StatePublished - Aug 2013
Externally publishedYes

Fingerprint

TNF Receptor-Associated Factor 6
TNF Receptor-Associated Factor 2
Double-Stranded RNA
Protein Kinases
Toxoplasma
Autophagy
Ligation
Macrophages
Microglia
Parasites
Binding Sites
Phosphorylation
Parasite Load
Disease Resistance
Toxoplasmosis
Brain
Vacuoles
Immunoprecipitation
Interleukin-10
Antiviral Agents

ASJC Scopus subject areas

  • Microbiology
  • Parasitology
  • Virology
  • Immunology
  • Genetics
  • Molecular Biology
  • Medicine(all)

Cite this

The Protein Kinase Double-Stranded RNA-Dependent (PKR) Enhances Protection against Disease Cause by a Non-Viral Pathogen. / Ogolla, Pauline Sebby; Portillo, Jose Andres C; White, Christine L.; Patel, Krupen; Lamb, Bruce; Sen, Ganes C.; Subauste, Carlos S.

In: PLoS Pathogens, Vol. 9, No. 8, e1003557, 08.2013.

Research output: Contribution to journalArticle

Ogolla, Pauline Sebby ; Portillo, Jose Andres C ; White, Christine L. ; Patel, Krupen ; Lamb, Bruce ; Sen, Ganes C. ; Subauste, Carlos S. / The Protein Kinase Double-Stranded RNA-Dependent (PKR) Enhances Protection against Disease Cause by a Non-Viral Pathogen. In: PLoS Pathogens. 2013 ; Vol. 9, No. 8.
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