bioRxiv ScienceSearch

bioRxiv · 10.1101/708750

Regulation of Hepatic MicroRNAs in Response to Early Stage Echinococcus multilocularis Egg Infection in C57BL/6 mice

Abstract

In this study, we present a comprehensive analysis of the hepatic miRNA transcriptome in mice suffering from experimental primary alveolar echinococcosis (AE), a parasitic infection caused upon ingestion of Echinococcus multilocularis (E. multilocularis) eggs. At one month post-infection, infected C57BL/6 mice, along with non-infected control mice, were euthanized. Subsequently livers were collected and used for small RNA library preparation and next-generation sequencing (NGS). The most significantly dysregulated hepatic miRNAs were validated by Stem-loop RT-qPCR. We identified 28 miRNAs with significantly altered expression levels upon infection with E. multilocularis. Of these, 9 were up-regulated (fold change (FC) [≥] 1.5) and 19 were down-regulated (FC [≤] 0.66) as compared to the non-infected controls. In infected liver tissues, mmu-miR-148a-3p and mmu-miR-101b-3p were 8- and 6-fold down-regulated, respectively, and the expression of mmu-miR-22-3p was reduced by 50%, compared to non-infected liver tissue. Conversely, significantly higher hepatic levels were noted for Mus musculus (mmu)-miR-21a-5p (FC = 2.3) and mmu-miR-122-5p (FC = 1.8). Down-regulated miRNAs were highly enriched in Reactome and KEGG pathways of angiogenesis and fatty acids biosynthesis. Moreover, relative mRNA expression levels of three pro-angiogenic (VEGFA, MTOR and HIF1-) and two lipogenic (FASN and ACSL1) genes were significantly higher in livers of E. multilocularis infected mice. Lastly, we studied the issue related to functionally mature arm selection preference (5p and/or 3p) from the miRNA precursor and showed that 9 pre-miRNAs exhibited different arm selection preferences in normal versus infected liver tissues. Our study provides first evidence of miRNA involvement in liver pathogenesis during AE. Our future research will focus on the characterization of miRNA transcriptome patterns in more advanced AE-stages towards the assessment of microRNA therapy for AE, and experimentally address functional characteristics of selected features presently found.\n\nAuthor SummaryVarious infectious diseases in humans have been associated with altered expression patterns of microRNAs (miRNAs), a class of small non-coding RNAs involved in negative regulation of gene expression. Herein, we revealed that significant alterations of miRNA expression occurred in murine liver subsequently to experimental infection with Echinococcus multilocularis (E. multilocularis) eggs when compared to non-infected controls. At the early stage of murine AE, hepatic miRNAs were mainly downregulated. Respective target genes of the most extensively downregulated miRNAs were involved in angiogenesis and fatty acid synthesis. Indeed, angiogenic and lipogenic genes were found to be significantly higher expressed in E. multilocularis infected livers relative to non-infected controls. These boosted cellular pathways are advantageous for development of the E. multilocularis metacestodes, since this larval stage is not able to undertake de novo fatty acid synthesis, and angiogenesis allows the larvae to be periparasitically supplied by oxygen and nutrients and to get rid of waste products. More research on the miRNA transcriptome at more advanced infection-stages, and on the role of angiogenesis in E. multilocularis larval growth and metastasis, is required to assess the usefulness of microRNA- and anti-angiogenic therapies against E. multilocularis infection.

Source connections

Explore related subjects

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Gottstein, B., Boubaker, G., Strempel, S., Hemphill, A., Mueller, N., Wang, J., Spiliotis, M.. 2019-07-20. Regulation of Hepatic MicroRNAs in Response to Early Stage Echinococcus multilocularis Egg Infection in C57BL/6 mice. https://doi.org/10.1101/708750

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related preprints

A conserved cysteine-histidine-glutamate metal site identifies DUF501 (Rv1025), an essential uncharacterised protein family of Mycobacterium tuberculosis, as a candidate metalloenzyme and drug target

A substantial fraction of the Mycobacterium tuberculosis proteome remains functionally uncharacterised. Rv1025, a 155-residue protein carrying the domain of unknown function DUF501 (Pfam PF04417), is essential by transposon mutagenesis and vulnerable by CRISPR interference, an attractive but neglected drug target, yet has never been functionally described. The family (4,370 proteins, no Gene Ontology term, no solved structure) is uncharacterised across all organisms and essential in three Actinobacterial genera. A Foldseek search of the AlphaFold model against complete structural databases finds no significant homolog, indicating a novel fold. The operon eno-divIC-Rv1025-ppx2 is conserved across the Actinobacteria phylum, yet AlphaFold-Multimer finds no direct complex between Rv1025 and its neighbour DivIC. Instead, conservation across 8,700 homologous sequences reveals a near-invariant Cys113-His115-Glu59 cluster forming a pocket. Holo AlphaFold3 predictions with Zn, Fe and Mn confidently place a divalent metal on this triad at 2.25-2.47 A; mutating the triad relocates the metal, and an independent backbone-geometry predictor recovers the same site, confirming specificity. The triad is universal across the family: present in all 1,472 near-complete bacterial sequences of the Pfam alignment, with no non-conservative substitution among the 2,228 sequences examined, a defining feature of bacterial DUF501 rather than a mycobacterial peculiarity. We propose that DUF501 is a metal-binding protein and candidate metalloenzyme, the first functional hypothesis for this family, whose conserved, essential metal pocket is a promising drug target. As the predictions build on a conservation-defined site within a fully computational study, they are supportive rather than proof of metal occupancy and warrant experimental validation.

microbiology

Mycoplasmal endosymbionts of Trichomonas vaginalis are associated with reduced risk for Chlamydia trachomatis endometrial infection in asymptomatic, coinfected, women.

Trichomonas vaginalis is a protozoan parasite that causes trichomoniasis, the most common curable non-viral sexually transmitted infection, and Chlamydia trachomatis is a bacterial pathogen that can ascend to the upper genital tract and cause pelvic inflammatory disease, infertility, and ectopic pregnancy. T. vaginalis harbors bacterial endosymbionts, including Candidatus Malacoplasma girerdii, an obligate symbiont, and Metamycoplasma hominis, which can live freely or symbiotically. In a 16S rRNA sequencing study of the cervicovaginal microbiome of women at high risk for chlamydial infection, Ca. M. girerdii abundance was one of 13 features predicting lack of chlamydial spread to the endometrium, despite no direct association between T. vaginalis infection and reduced chlamydial ascension. Investigating the relationship between these microorganisms further, we found that T. vaginalis vaginal abundance correlated positively with chlamydial burden in women whose infection was confined to the cervix, while a nonsignificant inverse relationship was seen in women with endometrial spread. Among participants with high chlamydial burden, Ca. M. girerdii was detected exclusively in women without endometrial infection. Both endosymbionts trended toward more frequent detection, and higher abundance, in coinfected women without endometrial spread, while M. hominis abundance correlated strongly with T. vaginalis burden in this group. These findings suggest that mycoplasmal endosymbionts of T. vaginalis, rather than T. vaginalis itself, are microbial factors limiting chlamydial ascension, and point to a three-way interaction between parasite, endosymbiont, and bacterial pathogen that shapes upper genital tract C. trachomatis infection risk.

microbiology

Understanding the physiological alterations of Vibrio cholerae upon exposure to L-ascorbic acid

The scourge of cholera remains a major global public health threat. It affects up to 4 million people worldwide and causes tens of thousands of deaths each year. The disease is experiencing a concerning resurgence in many parts of Africa, the Middle East, and Asia. To effectively tackle cholera and circumvent rising antimicrobial resistance, targeted biological and preventive approaches, complementing traditional rehydration, are urgently needed. In this regard, our group has demonstrated the efficacy of L-ascorbic acid in controlling the growth and pathogenesis of Vibrio cholerae in vitro. The present work further provides a mechanistic elucidation of the L-ascorbic acid-mediated physiological changes in V. cholerae and also bolsters such a non-antibiotic approach to control cholera.

microbiology