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Published on: September 25, 2019
Characterisation of macrophage migration inhibitory factor from Eimeria species infectious to chickens
Katarzyna B Miska1, Raymond H Fetterer, Hyun S Lillehoj
1USDA/ARS, Animal Parasitic Diseases Laboratory, 10300 Baltimore Ave. BARC-East, Beltsville, MD 20705, USA. kmiska@anri.barc.usdau.gov
Abstract:
Macrophage migration inhibitory factor (MIF) was the first cytokine to be identified almost 40 years ago. Homologues of MIF have been isolated recently from invertebrates, making it an interesting molecule from an evolutionary as well as functional perspective. The present study represents the first report of MIF homologues in apicomplexan parasites, belonging to the genus Eimeria. A single full-length clone was isolated from Eimeria acervulina that shared between 35 and 38% amino acid identity with MIFs of vertebrates. A MIF cDNA from Eimeria tenella shared 64% amino acid identity with E. acervulina MIF. The mRNA expression was highest in merozoites, whereas developing oocysts and sporozoites expressed low to undetectable levels. Protein expression patterns were nearly identical to that observed by reverse transcriptase polymerase chain reaction (RT-PCR), suggesting strong developmental regulation. Immunofluorescence staining and co-localisation studies of E. acervulina merozoites indicated that MIF is distributed throughout the cytosol, and appears to be concentrated in the apical end of the parasite. The presence of MIF was detected in excretory/secretory (ES) products collected from E. acervulina merozoites, and isoelectric focusing indicated that three MIF isoforms are present in this stage. Phylogenetic analysis revealed that apicomplexan MIF sequences form a sister relationship to MIF-like molecules from Arabidopsis thaliana.
Insights
This study identifies Macrophage Migration Inhibitory Factor (MIF) homologues in Eimeria parasites, revealing its presence in merozoites and excretory-secretory products. These findings offer insights into MIF evolution and function in apicomplexans.
Area of Science:
- Parasitology
- Molecular Biology
- Evolutionary Biology
Background:
- Macrophage Migration Inhibitory Factor (MIF) is a well-characterized cytokine with diverse functions.
- MIF homologues have been identified in various organisms, including invertebrates, highlighting its evolutionary significance.
- Apicomplexan parasites, such as Eimeria, are significant veterinary and human pathogens.
Purpose of the Study:
- To identify and characterize Macrophage Migration Inhibitory Factor (MIF) homologues in apicomplexan parasites of the genus Eimeria.
- To investigate the expression patterns and subcellular localization of Eimeria MIF.
- To explore the evolutionary relationships of apicomplexan MIF.
Main Methods:
- Isolation and sequencing of MIF cDNA from Eimeria acervulina and Eimeria tenella.
- Reverse transcriptase polymerase chain reaction (RT-PCR) for mRNA expression analysis.
- Immunofluorescence staining and co-localization studies for protein localization.
- Isoelectric focusing to analyze protein isoforms.
- Phylogenetic analysis to determine evolutionary relationships.
Main Results:
- Novel MIF homologues were identified in Eimeria acervulina and Eimeria tenella, sharing 35-38% amino acid identity with vertebrate MIFs.
- Eimeria MIF mRNA and protein expression were highest in merozoites, with low to undetectable levels in oocysts and sporozoites, indicating developmental regulation.
- MIF was localized to the cytosol and concentrated in the apical end of E. acervulina merozoites.
- MIF was detected in excretory/secretory (ES) products of E. acervulina merozoites, with three isoforms identified.
- Phylogenetic analysis placed apicomplexan MIF sequences as sister to MIF-like molecules from Arabidopsis thaliana.
Conclusions:
- This study provides the first report of MIF homologues in apicomplexan parasites.
- Eimeria MIF is developmentally regulated and secreted, suggesting a role in parasite-host interactions or parasite biology.
- The evolutionary analysis indicates a conserved lineage of MIF-like molecules across diverse eukaryotes.
