title: Toxoplasma gondii infection of fibroblasts causes the production of exosome-like vesicles containing a unique array of mRNA and miRNA transcripts compared to serum starvation.
abstract: BACKGROUND
  Until recently thought to be of little significance unless occurring during pregnancy, Toxoplasma gondii infection of human hosts is now known to play a larger role in mental health and is a growing concern in the health care community. We sought to elucidate a possible mechanism by which Toxoplasma infection may cause some of the behavioural pathology now associated with infection. We hypothesized that exosomes may be playing a role.
  
  
  METHODS
  We utilized electron microscopy to detect the presence and size of extracellular vesicles in the supernatants of Toxoplasma-infected human foreskin fibroblasts (HFF). We then utilized microarray analysis to discern mRNA and miRNA content of the vesicles isolated from supernatants of Toxoplasma-infected (Toxo) and serum-starved (SS) HFF.
  
  
  RESULTS
  We recovered extracellular vesicles with a size consistent with exosomes that we called exosome-like vesicles (ELVs) from the supernatants of SS and Toxo cultures. The mRNA and miRNA content of these ELVs was highly regulated creating specific and unique expression profiles comparing Toxo ELVs, SS ELVs and RNA isolated from whole cell homogenates. Interestingly, among the most enriched mRNA isolated from ELVs of Toxo cells are 4 specific mRNA species that have been described in the literature as having neurologic activity: Rab-13, eukaryotic translation elongation factor 1 alpha 1, thymosin beta 4 and LLP homolog. In addition, miRNA species uniquely expressed in Toxo ELVs include miR-23b, a well-known regulator of IL-17.
  
  
  CONCLUSIONS
  While the production of ELVs containing mRNAs that modify behaviour are consistent with reported Toxoplasma pathology, the mechanism of enrichment and ultimate in vivo effect of these mRNA and miRNA containing ELVs remains to be investigated.
authors.affiliation: Department of Biomedical Sciences, Marian University College of Osteopathic Medicine, Indianapolis IN, USA.
authors.forename: Samuel M
authors.initials: SM
authors.lastname: Pope
authors.affiliation: Department of Internal Medicine and Clinical Nutrition, Krefting Research Centre, University of Gothenburg, Gothenburg, Sweden.
authors.forename: Cecilia
authors.initials: C
authors.lastname: Lässer
keywords: Toxoplasma; exosomes; extracellular vesicles; mRNA; miRNA; microarray