Biology subjects

Nahori, M.-A.

Publications and source records attributed to Nahori, M.-A..

3 recordsLinked to original sources

bioRxiv2019

Specific targeting of intestinal Prevotella copri by a Listeria monocytogenes bacteriocin

Deciphering the specific function of every microorganism in microbial gut communities is a key issue to interrogate their role during infection. Here, we report the discovery of a Listeria bacteriocin, Lmo2776, that specifically targets the abundant gut commensal Prevotella copri and affects Listeria infection. Oral infection of conventional mice with a {Delta}lmo2776 mutant leads to a thinner intestinal mucus layer and higher Listeria loads both in the intestinal content and deeper tissues compared to WT Listeria, while no difference is observed in germ-free mice. This microbiota-dependent effect is phenocopied by precolonization of germ-free mice before Listeria infection, with P. copri, but not with other commensals. Together, these data unveil a role for Prevotella in controlling intestinal infection, highlighting that pathogens may selectively deplete microbiota to avoid excessive inflammation.

microbiology↗

bioRxiv2019

An RNA-binding protein secreted by Listeria monocytogenes activates RIG-I signaling

Recent studies have reported on the presence of bacterial RNA within or outside extracellular membrane vesicles, possibly as ribonucleoprotein complexes. Proteins that bind and stabilize bacterial RNAs in the extracellular environment have not been reported. Here, we show that the bacterial pathogen Listeria monocytogenes secretes a small RNA binding protein that we named Zea. We show that Zea binds and stabilizes a subset of L. monocytogenes RNAs causing their accumulation in the extracellular medium. Furthermore, Zea binds RIG-I, the vertebrate non-self-RNA innate immunity sensor and potentiates RIG-I-signaling leading to interferon {beta} production. By performing in vivo infection, we finally show that Zea modulates L. monocytogenes virulence. Together, this study reveals that bacterial extracellular RNAs and RNA binding proteins can affect the host-pathogen crosstalk.

cell biology↗

bioRxiv2018

A role for gut microbiota in m6A epitranscriptomic mRNA modifications in different host tissues

The intestinal microbiota modulates host physiology and gene expression via mechanisms that are not fully understood. A recently discovered layer of gene expression regulation is N6-methyladenosine (m6A) modification of mRNA. To unveil if this epitranscriptomic mark in part mediates the impact of the gut microbiota on the host, we analyzed m6A-modifications in transcripts of mice displaying either a conventional, or a modified, or no gut flora. We discovered that the microbiota has a strong influence on m6A-modifications in the cecum, and also, albeit to a lesser extent, in the liver. We furthermore show that a single commensal bacterium, Akkermansia muciniphila, can affect specific m6A modifications. Together, we report here epitranscriptomic modifications as an unexpected level of interaction in the complex interplay between commensal bacteria and their host.

molecular biology↗