Chronic Trichuris muris Infection Decreases Diversity of the Intestinal Microbiota and Concomitantly Increases the Abundance of Lactobacilli.
The intestinal microbiota is vital for shaping the local intestinal environment as well as host immunity and metabolism. At the same time, epidemiological and experimental evidence suggest an important role for parasitic worm infections in maintaining the inflammatory and regulatory balance of the immune system. In line with this, the prevalence of persistent worm infections is inversely correlated with the incidence of immune-associated diseases, prompting the use of controlled parasite infections for therapeutic purposes. Despite this, the impact of parasite infection on the intestinal microbiota, as well as potential downstream effects on the immune system, remain largely unknown. We have assessed the influence of chronic infection with the large-intestinal nematode Trichuris muris, a close relative of the human pathogen Trichuris trichiura, on the composition of the murine intestinal microbiota by 16S ribosomal-RNA gene-based sequencing. Our results demonstrate that persistent T. muris infection dramatically affects the large-intestinal microbiota, most notably with a drop in the diversity of bacterial communities, as well as a marked increase in the relative abundance of the Lactobacillus genus. In parallel, chronic T. muris infection resulted in a significant shift in the balance between regulatory and inflammatory T cells in the intestinal adaptive immune system, in favour of inflammatory cells. Together, these data demonstrate that chronic parasite infection strongly influences the intestinal microbiota and the adaptive immune system. Our results illustrate the complex interactions between these factors in the intestinal tract, and contribute to furthering the understanding of this interplay, which is of crucial importance considering that 500 million people globally are suffering from these infections and their potential use for therapeutic purposes.
Laboratory of Genomics and Molecular Biomedicine, Department of Biology, University of Copenhagen, Copenhagen, Denmark.
Jacob Bak
JB
Holm
Immunology Section, Department of Experimental Medical Sciences, Medical Faculty, Lund University, Lund, Sweden.
Daniel
D
Sorobetea
Laboratory of Genomics and Molecular Biomedicine, Department of Biology, University of Copenhagen, Copenhagen, Denmark.
Pia
P
Kiilerich
INRA, UMR1313 Génétique Animale et Biologie Intégrative (GABI), Jouy-en-Josas, France.
Yuliaxis
Y
Ramayo-Caldas
INRA, UMR1313 Génétique Animale et Biologie Intégrative (GABI), Jouy-en-Josas, France.
Jordi
J
Estellé
Laboratory of Genomics and Molecular Biomedicine, Department of Biology, University of Copenhagen, Copenhagen, Denmark.
Tao
T
Ma
Laboratory of Genomics and Molecular Biomedicine, Department of Biology, University of Copenhagen, Copenhagen, Denmark; National Institute of Nutrition and Seafood Research, Bergen, Norway.
Lise
L
Madsen
Laboratory of Genomics and Molecular Biomedicine, Department of Biology, University of Copenhagen, Copenhagen, Denmark.
Karsten
K
Kristiansen
Immunology Section, Department of Experimental Medical Sciences, Medical Faculty, Lund University, Lund, Sweden.
Marcus
M
Svensson-Frej
D000818:Animals; D044822:Biodiversity; D002908:Chronic Disease; D000069196:Gastrointestinal Microbiome; D007413:Intestinal Mucosa / Q000276:immunology / Q000382:microbiology* / Q000469:parasitology*; D007778:Lactobacillus / Q000276:immunology; D008297:Male; D051379:Mice; D023421:Models, Animal; D016176:T-Lymphocyte Subsets / Q000276:immunology / Q000378:metabolism; D013997:Time Factors; D014257:Trichuriasis / Q000469:parasitology*; D014258:Trichuris