A detailed view of the intracellular transcriptome of Listeria monocytogenes in murine macrophages using RNA-seq

Abstract

Listeria monocytogenes is a bacterial pathogen and causative agent for the foodborne infection listeriosis, which is mainly a threat for pregnant, elderly, or immunocompromised individuals. Due to its ability to invade and colonize diverse eukaryotic cell types including cells from invertebrates, L. monocytogenes has become a well-established model organism for intracellular growth. Almost 10 years ago, we and others presented the first whole-genome microarray-based intracellular transcriptome of L. monocytogenes. With the advent of newer technologies addressing transcriptomes in greater detail, we revisit this work, and analyze the intracellular transcriptome of L. monocytogenes during growth in murine macrophages using a deep sequencing based approach. We detected 656 differentially expressed genes of which 367 were upregulated during intracellular growth in macrophages compared to extracellular growth in Brain Heart Infusion broth. This study confirmed ∼64% of all regulated genes previously identified by microarray analysis. Many of the regulated genes that were detected in the current study involve transporters for various metals, ions as well as complex sugars such as mannose. We also report changes in antisense transcription, especially upregulations during intracellular bacterial survival. A notable finding was the detection of regulatory changes for a subset of temperate A118-like prophage genes, thereby shedding light on the transcriptional profile of this bacteriophage during intracellular growth. In total, our study provides an updated genome-wide view of the transcriptional landscape of L. monocytogenes during intracellular growth and represents a rich resource for future detailed analysis.

Transcriptome Sequencing of Listeria monocytogenes Reveals Major Gene Expression Changes in Response to Lactic Acid Stress Exposure but a Less Pronounced Response to Oxidative Stress

“…Previous studies have demonstrated that the presence of lysogenic prophages in a genome can confer beneficial effects (Edlin et al, 1977;Burns et al, 2015) including tolerance to acid stress (Wang et al, 2010). In L. monocytogenes, an induction of prophage gene expression has recently been reported during intracellular replication (Hain et al, 2012;Schultze et al, 2015) and for the L. monocytogenes 10403S A118 prophage after acid stress exposure (Ivy et al, 2012). The tRNA-Arg-TCT prophage is found in both 6179 and R479a.…”

Listeria monocytogenesencodes a functional ESX-1 secretion system whose expression is detrimental toin vivoinfection

“…Regarding the expression of ESX-1 genes in different conditions, no change was observed when bacteria were grown at 37 C, 25 C or 7 C, 29,30 nor in presence of 6% NaCl, 29 nor when grown at pH 5, 31 nor when grown in culture media supplemented with glucose, cellobiose or glycerol. 32,33 In addition, as compared to bacteria grown in BHI at 37 C, the expression of the ESX-1 locus appears also unchanged in Listeria recovered from infected murine macrophages, 34,35 or from mouse intestinal lumen 36 and spleens. 37 Interestingly, the entire ESX-1 locus was shown as up-regulated after incubation of Lm in human blood, and essC and esxC were also shown as upregulated during cell infection.…”

Proyectos relacionados con diversidad, ecología, desplazamiento, virulencia y potencial biotecnológico de cepas de Listeria spp. aisladas en Costa Rica a partir de muestras alimentarias, clínicas y ambientales

“…Además de su importancia clínica, L. monocytogenes ha sido mundialmente estudiada como un modelo de patogénesis intracelular, lo cual ha permitido descifrar información importante sobre el comportamiento del patógeno, como es el caso de la respuesta a la actividad antibiótica intracelular, transcripción de genes durante la vida intracelular [7] y desarrollo de modelos in vivo para el estudio de infecciones [8]. Desde finales de 1980, los estudios realizados en biología celular combinado con biología molecular y genómica han elucidado la estrategia utilizada por L. monocytogenes para ingresar al hospedero, multiplicarse y propagarse entre célula-célula.…”