Transcriptome profiling of gene expression during immunisation trial against Fasciola hepatica: identification of genes and pathways involved in conferring immunoprotection in a murine model

Abstract

BackgroundFasciolosis remains a significant food-borne trematode disease causing high morbidity around the world and affecting grazing animals and humans. A deeper understanding concerning the molecular mechanisms by which Fasciola hepatica infection occurs, as well as the molecular basis involved in acquiring protection is extremely important when designing and selecting new vaccine candidates. The present study provides a first report of microarray-based technology for describing changes in the splenic gene expression profile for mice immunised with a highly effective, protection-inducing, multi-epitope, subunit-based, chemically-synthesised vaccine candidate against F. hepatica.MethodsThe mice were immunised with synthetic peptides containing B- and T-cell epitopes, which are derived from F. hepatica cathepsin B and amoebapore proteins, as novel vaccine candidates against F. hepatica formulated in an adjuvant adaptation vaccination system; they were experimentally challenged with F. hepatica metacercariae. Spleen RNA from mice immunised with the highest protection-inducing synthetic peptides was isolated, amplified and labelled using Affymetrix standardised protocols. Data was then background corrected, normalised and the expression signal was calculated. The Ingenuity Pathway Analysis tool was then used for analysing differentially expressed gene identifiers for annotating bio-functions and constructing and visualising molecular interaction networks.ResultsMice immunised with a combination of three peptides containing T-cell epitopes induced high protection against experimental challenge according to survival rates and hepatic damage scores. It also induced differential expression of 820 genes, 168 genes being up-regulated and 652 genes being down-regulated, p value <0.05, fold change ranging from −2.944 to 7.632. A functional study of these genes revealed changes in the pathways related to nitric oxide and reactive oxygen species production, Interleukin-12 signalling and production in macrophages and Interleukin-8 signalling with up-regulation of S100 calcium-binding protein A8, Matrix metallopeptidase 9 and CXC chemokine receptor 2 genes.ConclusionThe data obtained in the present study provided us with a more comprehensive overview concerning the possible molecular pathways implied in inducing protection against F. hepatica in a murine model, which could be useful for evaluating future vaccine candidates.Electronic supplementary materialThe online version of this article (doi:10.1186/s12879-017-2205-3) contains supplementary material, which is available to authorized users.

Characterization of dendritic cells and follicular dendritic cells in the hepatic lymph nodes and liver of sheep experimentally infected with Fasciola hepatica

“…Transcriptomic analysis of PBMCs from sheep revealed an upregulation of S100 genes at 2 weeks post-infection, and these cells were shown to be involved in leukocyte migration and the innate immune response [49]. In a murine model, the S100A8 gene was also overexpressed in F. hepatica infections [50].…”

Advances in Fasciola hepatica research using ‘omics’ technologies

“…In addition, these approaches are being used to evaluate potential vaccine candidates, identifying the genes involved in conferring protection (Wesołowska et al, 2013;Rojas-Caraballo et al, 2017).…”

Expression of free radicals by peritoneal cells of sheep during the early stages of Fasciola hepatica infection

“…The role of H 2 O 2 in F. hepatica infection remains unclear. Transcriptome studies in mice revealed production of ROS as one the most significant pathways undergoing changes during immunoprotection [ 27 ] but it has also been related to oxidative stress and pathology in chronic infection in sheep [ 20 ]. Moreover, different in vitro studies indicate that F. hepatica NEJ possess a unique ability to resist killing by reactive oxygen species released by sheep innate immune effector cells, which may involve the high expression of antioxidant enzymes such as superoxide dismutase, glutathione S-transferase (GST) or peroxiredoxin [ 28 – 31 ].…”

“…It has been hypothesised that NO and iNOS might play an important role in F. hepatica pathogenesis, possibly as an effective mechanism for killing migrating NEJ, as it has been previously shown to occur in resistant rats [ 31 ] or maybe as an expression of M1 macrophages activation which are known to be related to the development of Th1 responses required for protection [ 18 , 32 , 33 ]. Recent transcriptomic studies have revealed that modifications in the NO signalling pathway may be a necessary condition for immunoprotection in mice [ 27 ] or, on the contrary, downregulation of iNOS might be a paramount factor during the non-protective response occurring in sheep [ 34 ]. In our study, we have not detected an inhibition in NO production in the early phase of infection.…”