Transcriptome analysis of Neisseria meningitidis in human whole blood and mutagenesis studies identify virulence factors involved in blood survival

Autor: Mariagrazia Pizza, Hebert Echenique-Rivera, Rino Rappuoli, Elena Del Tordello, Alessandro Muzzi, Patrice Francois, Davide Serruto, Kate L. Seib
Jazyk: angličtina
Rok vydání: 2011
Předmět:
Male
Antigens
Bacterial/genetics
Bacteremia
Pathogenesis
Neisseria meningitidis
Serogroup B
Transcriptome
Cluster Analysis
lcsh:QH301-705.5
Whole blood
Sequence Deletion
Genetics
Regulation of gene expression
ddc:616
Genomics
Down-Regulation/genetics
Adaptation
Physiological
Host-Pathogen Interactions/genetics
Up-Regulation
Host-Pathogen Interaction
RNA
Bacterial
Host-Pathogen Interactions
Genes
Bacterial/genetics
Female
Research Article
lcsh:Immunologic diseases. Allergy
Adult
Virulence Factors/genetics
Virulence Factors
Immunology
Hypothetical protein
Virulence
Mutagenesis (molecular biology technique)
Down-Regulation
Biology
DNA-binding protein
Microbiology
Models
Biological
Neisseria meningitidis
Serogroup B/genetics/growth & development/pathogenicity/physiology
Up-Regulation/genetics
Bacterial Proteins
Bacteremia/blood/microbiology
Virology
Humans
Meningococcal Infections/blood/microbiology
Molecular Biology
Gene
Microbial Pathogens
Antigens
Bacterial
Bacterial Proteins/genetics
Gene Expression Regulation
Bacterial
Gene Expression Regulation
Bacterial/genetics
Genome
Bacterial/genetics
Meningococcal Infections
lcsh:Biology (General)
Genes
Bacterial
Parasitology
Genome Expression Analysis
lcsh:RC581-607
Genome
Bacterial
RNA
Bacterial/genetics
Zdroj: PLOS Pathogens, Vol. 7, No 5 (2011) P. e1002027
PLoS Pathogens, Vol 7, Iss 5, p e1002027 (2011)
PLoS Pathogens
ISSN: 1553-7366
Popis: During infection Neisseria meningitidis (Nm) encounters multiple environments within the host, which makes rapid adaptation a crucial factor for meningococcal survival. Despite the importance of invasion into the bloodstream in the meningococcal disease process, little is known about how Nm adapts to permit survival and growth in blood. To address this, we performed a time-course transcriptome analysis using an ex vivo model of human whole blood infection. We observed that Nm alters the expression of ≈30% of ORFs of the genome and major dynamic changes were observed in the expression of transcriptional regulators, transport and binding proteins, energy metabolism, and surface-exposed virulence factors. In particular, we found that the gene encoding the regulator Fur, as well as all genes encoding iron uptake systems, were significantly up-regulated. Analysis of regulated genes encoding for surface-exposed proteins involved in Nm pathogenesis allowed us to better understand mechanisms used to circumvent host defenses. During blood infection, Nm activates genes encoding for the factor H binding proteins, fHbp and NspA, genes encoding for detoxifying enzymes such as SodC, Kat and AniA, as well as several less characterized surface-exposed proteins that might have a role in blood survival. Through mutagenesis studies of a subset of up-regulated genes we were able to identify new proteins important for survival in human blood and also to identify additional roles of previously known virulence factors in aiding survival in blood. Nm mutant strains lacking the genes encoding the hypothetical protein NMB1483 and the surface-exposed proteins NalP, Mip and NspA, the Fur regulator, the transferrin binding protein TbpB, and the L-lactate permease LctP were sensitive to killing by human blood. This increased knowledge of how Nm responds to adaptation in blood could also be helpful to develop diagnostic and therapeutic strategies to control the devastating disease cause by this microorganism.
Author Summary Neisseria meningitidis (Nm) is an exclusively human pathogen and a leading cause of bacterial meningitis and septicemia worldwide. Characterization of the bacterial transcriptome during host-pathogen interactions is a fundamental step for understanding the infectious processes of bacterial pathogens. Despite the severity of meningococcal sepsis, little is known about how Nm adapts to permit survival and growth in human blood. In this work we report the transcriptional response of Nm after incubation in human whole blood. The gene expression results indicate that a significant part of the ORFs of the genome (≈30%) is differentially expressed after incubation in human blood, with genes involved in adaptation of Nm metabolism to blood and in virulence and subversion of the host immune system being up-regulated. Combining transcriptional analysis with the generation and characterization of deletion mutants and complementing strains, we identify new factors important for survival in human blood. This first gene expression analysis of Nm in blood significantly increases our knowledge of how this bacterium responds to human blood and causes septicemia. Our results also provide new information on gene function and may ultimately help in the development of diagnostic and therapeutic strategies to control this devastating disease.
Databáze: OpenAIRE
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