RESUMO
The liver fluke Opisthorchis felineus is a clinically important food-borne parasite of humans. Infection with O. felineus in mammals is associated with liver morbidities such as periductal fibrosis, bile duct neoplasia, and chronic inflammation. Previously we have shown that excretory-secretory products (ESP) can stimulate the healing of skin wounds in mice, which may be due to stimulated angiogenesis and extracellular matrix remodeling. However, there are no studies analyzing the angiogenic character of O. felineus, and its effects on angiogenesis, vascularity, and vascular endothelium. The aim of this study was to evaluate the capacity of ESP and extracellular vesicles (EVs) of O. felineus to stimulate angiogenesis and the formation of pseudo-capillaries in vitro. We also aimed at the assessment of the angiogenesis during the infection in vivo, and estimation of the endothelial cell type abundances from heterogeneous bulk liver transcriptome between uninfected and infected animals with single-cell information. The study revealed significant alterations in vascularity in the hamster liver and significant involvement of portal endothelial cells at the transcriptome level. We also demonstrated that the ESP and EVs of O. felineus have the capacity to stimulate the formation of pseudo-capillaries in vitro. Both ESP and EVs appeared to have similar effects on all four parameters, increasing node formation and total master segments length, and significantly decreasing total isolated branches length and number of isolated segments of pseudo-capillaries. The liver flukes manipulate the host's angiogenic response, a fact that has been related to the pathogenesis caused by these parasites. Understanding these pathogenic mechanisms may uncover new therapeutic targets to relieve or prevent the most severe complications of opisthorchiasis.
RESUMO
BACKGROUND: Opisthorchis felineus, Opisthorchis viverrini and Clonorchis sinensis are epidemiologically significant food-borne trematodes endemic to diverse climatic areas. O. viverrini and C. sinensis are both recognized to be 1A group of biological carcinogens to human, whereas O. felineus is not. The mechanisms of carcinogenesis by the liver flukes are studied fragmentarily, the role of host and parasite microbiome is an unexplored aspect. METHODOLOGY/PRINCIPAL FINDINGS: Specific pathogen free Mesocricetus auratus hamsters were infected with C. sinensis, O. viverrini and O. felineus. The microbiota of the adult worms, colon feces and bile from the hamsters was investigated using Illumina-based sequencing targeting the prokaryotic 16S rRNA gene. The analysis of 43 libraries revealed 18,830,015 sequences, the bacterial super-kingdom, 16 different phyla, 39 classes, 63 orders, 107 families, 187 genera-level phylotypes. O. viverrini, a fluke with the most pronounced carcinogenic potential, has the strongest impact on the host bile microbiome, changing the abundance of 92 features, including Bifidobacteriaceae, Erysipelotrichaceae, [Paraprevotellaceae], Acetobacteraceae, Coriobacteraceae and Corynebacteriaceae bacterial species. All three infections significantly increased Enterobacteriaceae abundance in host bile, reduced the level of commensal bacteria in the gut microbiome (Parabacteroides, Roseburia, and AF12). CONCLUSIONS/SIGNIFICANCE: O. felineus, O. viverrini, and C. sinensis infections cause both general and species-specific qualitative and quantitative changes in the composition of microbiota of bile and colon feces of experimental animals infected with these trematodes. The alterations primarily concern the abundance of individual features and the phylogenetic diversity of microbiomes of infected hamsters.