Project description:Giardia duodenalis is a prevalent intestinal pathogens known to cause giardiasis, a condition characterized by diarrhea and frequently linked to malnutrition and growth impairments in children. The presence of Giardiavirus (GLV) in Giardia strains has been associated with heightened immune cytokine responses in the host compared to the GLV-free strains. However, the transmission mode and biological significance of GLV remain unclear. In this study, by using G. duodenalis DH (GLV-containing) and WBC6 (GLV-free) strains, we demonstrated that the DH strain produced extracellular vesicles (EVs), which originated from unique peripheral vesicle and bead-like structures in the ventrolateral flange. Nanoparticle tracking analysis revealed that GLV infected-G. duodenalis DH strain secreted fewer EVs than the GLV-free WBC6 strain. Biochemical and electron microscopy demonstrated that GLV virions can exploit the Giardia EVs pathway to facilitate their spread among parasites. Giardia uptake of GLV-containing EVs occured through clathrin-mediated endocytosis, leading to rapid infection of trophozoites by GLV. Furthermore, GLV infection enhanced messenger RNA translation efficiency, influencing protein abundance in Giardia trophozoites. The presence of GLV also upregulated the glycolytic pathway, with Giardia enolase closely associated with GLV replication. Importantly, Giardia infected with GLV alleviated the pathogenicity of parasite compared to the GLV-freeGiardia strain. These findings highlight the pivotal role of GLV in regulating Giardia biology, suggesting its potential for informing the development of novel intervention strategies against Giardia infections.
Project description:Despite of Giardia duodenalis being one of the most commonly found intestinal pathogens in humans and animals, little is known of the host-parasite interactions in natural hosts. Therefore, the objective of this study was to investigate the intestinal response in calves following a G. duodenalis infection, using a bovine high-density oligo microarray to analyze global gene expression in the small intestine. The resulting microarray data suggested a decrease in inflammation, immune response and immune cell migration in infected animals, which was examined in more detail by quantitative real-time PCR on a panel of cytokines combined with histological analyses. The cytokine transcription levels showed a trend of down regulated expression in infected animals compared to the negative controls, best seen in jejunum for IL-6 and IL-8 and statistically significant for IL-17, IL-13 and IFN-?. No increased immune cell recruitment could be seen after infection, as well as no intestinal pathologies, such as villus shortening or increased levels of apoptosis. Key regulators in this intestinal response seem to be the nuclear peroxisome proliferator-activated receptors alpha (PPARA) and gamma (PPARG), for which an up-regulated expression was seen on microarray and qRT-PCR data. The activation of PPARs can exert an anti-inflammatory effect with inhibition of pro-inflammatory cytokines and a decrease in cell recruitment. . How the PPARs are activated during a Giardia infection still needs to be further elucidated. Eight male Holstein calves aged two to four weeks old were used for the trial. Prior to arrival, all animals were screened for the presence of Giardia cysts in their faecal samples. After confirming their negative status for all these pathogens, four of the animals were randomly chosen and placed in a G. duodenalis contaminated environment, whereas the four remaining animals were kept as negative controls in separate G. duodenalis-free stables. All calves in the study received the same commercial milk replacer. After three weeks, the presence or absence of a G. duodenalis infection was confirmed by IFA on faecal samples after which the animals were euthanized. Changes in gene expression profiles induced by Giardia duodenalis infection were compared using a high-density 60mer bovine oligo microarray.
Project description:Gibel carp (Carassius gibelio) is a cyprinid fish that originated in eastern Eurasia and is considered as invasive in European freshwater ecosystems. The populations of gibel carp in Europe are mostly composed of asexually reproducing triploid females (i.e., reproducing by gynogenesis) and sexually reproducing diploid females and males. Although some cases of coexisting sexual and asexual reproductive forms are known in vertebrates, the molecular mechanisms maintaining such coexistence are still in question. Both reproduction modes are supposed to exhibit evolutionary and ecological advantages and disadvantages. To better understand the coexistence of these two reproduction strategies, we performed transcriptome profile analysis of gonad tissues (ovaries), and studied the differentially expressed reproduction-associated genes in sexual and asexual females. We used high-throughput RNA sequencing to generate transcriptomic profiles of gonadal tissues of triploid asexual females and males, diploid sexual males and females of gibel carp, as well as diploid individuals from two closely-related species, C. auratus and Cyprinus carpio. Using SNP clustering, we showed the close similarity of C. gibelio and C. auratus with a basal position of C. carpio to both Carassius species. Using transcriptome profile analyses, we showed that many genes and pathways are involved in both gynogenetic and sexual reproduction in C. gibelio; however, we also found that 1500 genes, including 100 genes involved in cell cycle control, meiosis, oogenesis, embryogenesis, fertilization, steroid hormone signaling and biosynthesis were differently expressed in the ovaries of asexual and sexual females. We suggest that the overall downregulation of reproduction-associated pathways in asexual females, and their maintenance in sexual ones, allow for their stable coexistence, integrating the evolutionary and ecological advantages and disadvantages of the two reproductive forms. However, we showed that many sexual-reproduction-related genes are maintained and expressed in asexual females, suggesting that gynogenetic gibel carp retains the genetic toolkits for meiosis and sexual reproduction. These findings shed new light on the evolution of this asexual and sexual complex.
Project description:<p>Giardia duodenalis is a prevalent intestinal parasite that cause giardiasis, a condition characterized by diarrhea and frequently linked to malnutrition and growth impairments in children. The presence of Giardiavirus (GLV) can lead to reduced pathological damage in mice infected with Giardia and different pro-inflammatory responses in host cells stimulated by Giardia. As is well known, viruses as “non-cellular organisms” that control host proteins, metabolic resources to complete replication and transmission. However, the understanding of the impact of the Giardiavirus on the G. duodenalis itself is currently limited. Here, we found that GLV infection can reduce the mRNA and expression levels of Giardia genes, but lead to upregulation of translation efficiency in Giardia genes. Additionally, GLV infection causes Giardia's energy metabolic reprogramming, 21 significantly different energy metabolites were identified, and the most significant pathway by KEGG enrichment was Glycolysis/ Gluconeogenesis. After the viral load of GLV stabilizes, glycolysis is significantly upregulated with increasing GLV infection generations. The glycolytic enzyme enolase in Giardia is closely associated with the viral load of GLV. and it was found that knocking down the expression level of enolase also led to a decrease in the viral load of GLV. Overall, these results highlight that GLV infection can regulate the protein and energy metabolism of G. duodenalis for its own survival, and discover the potential of GLV as a novel intervention strategy for the development of drugs and vaccines for the prevention and treatment of giardiasis.</p>
Project description:Homeostatic interactions between the host and its resident microbiota is important for normal physiological functions and if altered, it could lead to dysbiosis, a change in the structure and function of the microbiota, and as a result to various pathophysiologies. Altered structure in bacterial community is associated with various pathophysiologies, but we are just beginning to understand how these structural changes translate into functional changes. Environmental factors including pathogenic infections can lead to altered interactions between the host and its resident microbiota. We used microarray analysis and a C. elegans model system to gain insights on the mechanisms of functional changes in host-commensal bacteria interaction in the presence or absence of G. duodenalis and identified expression pattern in commensal bacteria that are characteristic of homeostatic and dysbiotic interactions. E. coli HB101 exposed to C. elegans in the presence or absence of G. duodenalis conditioned S-basal complete media for 24 hours were used for RNA extraction and hybridization on Affymetrix microarrays. We collected expression data for E. coli HB101, E. coli HB101 exposed to C. elegans, E. coli HB101 exposed to Giardia conditioned media, and E. coli HB101 exposed to both C. elegans and Giardia conditioned media.