RIG-I Detects mRNA of Intracellular <named-content content-type="genus-species">Salmonella enterica</named-content> Serovar Typhimurium during Bacterial Infection

ABSTRACT The cytoplasmic helicase RIG-I is an established sensor for viral 5′-triphosphorylated RNA species. Recently, RIG-I was also implicated in the detection of intracellular bacteria. However, little is known about the host cell specificity of this process and the bacterial pathogen-associated...

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Autores principales: Mirco Schmolke, Jenish R. Patel, Elisa de Castro, Maria T. Sánchez-Aparicio, Melissa B. Uccellini, Jennifer C. Miller, Balaji Manicassamy, Takashi Satoh, Taro Kawai, Shizuo Akira, Miriam Merad, Adolfo García-Sastre
Formato: article
Lenguaje:EN
Publicado: American Society for Microbiology 2014
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Acceso en línea:https://doaj.org/article/5c8c7580d0d14579892faa77373b07c6
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Sumario:ABSTRACT The cytoplasmic helicase RIG-I is an established sensor for viral 5′-triphosphorylated RNA species. Recently, RIG-I was also implicated in the detection of intracellular bacteria. However, little is known about the host cell specificity of this process and the bacterial pathogen-associated molecular pattern (PAMP) that activates RIG-I. Here we show that RNA of Salmonella enterica serovar Typhimurium activates production of beta interferon in a RIG-I-dependent fashion only in nonphagocytic cells. In phagocytic cells, RIG-I is obsolete for detection of Salmonella infection. We further demonstrate that Salmonella mRNA reaches the cytoplasm during infection and is thus accessible for RIG-I. The results from next-generation sequencing analysis of RIG-I-associated RNA suggest that coding bacterial mRNAs represent the activating PAMP. IMPORTANCE S. Typhimurium is a major food-borne pathogen. After fecal-oral transmission, it can infect epithelial cells in the gut as well as immune cells (mainly macrophages, dendritic cells, and M cells). The innate host immune system relies on a growing number of sensors that detect pathogen-associated molecular patterns (PAMPs) to launch a first broad-spectrum response to invading pathogens. Successful detection of a given pathogen depends on colocalization of host sensors and PAMPs as well as potential countermeasures of the pathogen during infection. RIG-I-like helicases were mainly associated with detection of RNA viruses. Our work shows that S. Typhimurium is detected by RIG-I during infection specifically in nonimmune cells.