title: Plasma microRNAs are promising novel biomarkers for the early detection of Toxoplasma gondii infection.
abstract: BACKGROUND
  MicroRNAs (miRNAs) have been shown to be present in plasma, which are remarkably stable, and have been suggested as disease biomarkers. Toxoplasma gondii (T. gondii) is a protozoan parasite that is infective to a wide range of animals and human beings. Previous studies have found that the parasite generated a large number of miRNAs during proliferation and it is known that the spectrum of miRNA expression in the infected hosts is pathogen-specific. To date, there are no reports regarding the application of microRNAs as biomarkers for the early detection of T. gondii infection.
  
  
  METHODS
  In this study, we investigated the expression patterns of 414 murine miRNAs and tested their expression levels in the plasma after T. gondii infection by real-time PCR, with an ultimate purpose of identifying infection-related miRNAs. Three miRNAs in particular, exhibiting prominently elevated expressions, were further validated in a large number of infected mice. The Toxoplasma infection-specific miRNAs were confirmed by comparing their expression levels with those of mice infected with Plasmodium berghei, P. yoelii, P. chabaudi, Cryptosporidium parvum, Mouse hepatitis virus, and Staphylococcus aureus.
  
  
  RESULTS
  Among the 414 miRNA candidates identified by a real-time PCR array, 71 were found to be up-regulated in the plasma of T. gondii infected mice. Three of those miRNAs (mmu-miR-712-3p, mmu-miR-511-5p and mmu-miR-217-5p) were prominently expressed in mice infected by both the RH and ME49 strains of T. gondii. Additionally, the elevated expression of these miRNAs was Toxoplasma-specific.
  
  
  CONCLUSIONS
  The levels of the three miRNAs, mmu-miR-712-3p, mmu-miR-511-5p and mmu-miR-217-5p miRNAs, were found specifically up-regulated in plasma of mice after T. gondii infection.
authors.forename: Boyin
authors.initials: B
authors.lastname: Jia
authors.forename: Zhiguang
authors.initials: Z
authors.lastname: Chang
authors.forename: Xiaoyan
authors.initials: X
authors.lastname: Wei
authors.forename: Huijun
authors.initials: H
authors.lastname: Lu
authors.forename: Jigang
authors.initials: J
authors.lastname: Yin
authors.affiliation: Key Laboratory of Zoonosis, Institute of Zoonosis/College of Veterinary Medicine, Jilin University, Xi An Da Lu 5333, Changchun 130062, China. jiangning@jlu.edu.cn.
authors.forename: Ning
authors.initials: N
authors.lastname: Jiang
authors.forename: Qijun
authors.initials: Q
authors.lastname: Chen
mesh_terms: D000818:Animals; D015415:Biomarkers / Q000097:blood; D004195:Disease Models, Animal; D042241:Early Diagnosis; D005260:Female; D005786:Gene Expression Regulation; D006801:Humans; D051379:Mice; D008807:Mice, Inbred BALB C; D035683:MicroRNAs / Q000097:blood* / Q000235:genetics; D014122:Toxoplasma / Q000235:genetics / Q000302:isolation & purification*; D014123:Toxoplasmosis / Q000175:diagnosis*; D015854:Up-Regulation
chemical_list: D015415:Biomarkers; C000591813:MIRN-217 microRNA, mouse; D035683:MicroRNAs; C578472:Mirn511 microRNA, mouse