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The Gonococcal Transcriptome during Infection of the Lower Genital Tract in Women.

McClure R, Nudel K, Massari P, Tjaden B, Su X, Rice PA, Genco CA - PLoS ONE (2015)

Bottom Line: Gonorrhea is a highly prevalent disease resulting in significant morbidity worldwide, with an estimated 106 cases reported annually.A total of 140 genes were increased in expression during natural infection compared to growth in CDM, and 165 genes were decreased in expression.Large differences were found in gene expression profiles under each condition, particularly with genes involved in DNA and RNA processing, iron, transposase, pilin and lipoproteins.

View Article: PubMed Central - PubMed

Affiliation: Department of Medicine, Section of Infectious Diseases, Boston University School of Medicine, Boston, MA, United States of America; Department of Microbiology, Boston University School of Medicine, Boston, MA, United States of America.

ABSTRACT
Gonorrhea is a highly prevalent disease resulting in significant morbidity worldwide, with an estimated 106 cases reported annually. Neisseria gonorrhoeae, the causative agent of gonorrhea, colonizes and infects the human genital tract and often evades host immune mechanisms until successful antibiotic treatment is used. The alarming increase in antibiotic-resistant strains of N. gonorrhoeae, the often asymptomatic nature of this disease in women and the lack of a vaccine directed at crucial virulence determinants have prompted us to perform transcriptome analysis to understand gonococcal gene expression patterns during natural infection. We sequenced RNA extracted from cervico-vaginal lavage samples collected from women recently exposed to infected male partners and determined the complete N. gonorrhoeae transcriptome during infection of the lower genital tract in women. On average, 3.19% of total RNA isolated from female samples aligned to the N. gonorrhoeae NCCP11945 genome and 1750 gonococcal ORFs (65% of all protein-coding genes) were transcribed. High expression in vivo was observed in genes encoding antimicrobial efflux pumps, iron response, phage production, pilin structure, outer membrane structures and hypothetical proteins. A parallel analysis was performed using the same strains grown in vitro in a chemically defined media (CDM). A total of 140 genes were increased in expression during natural infection compared to growth in CDM, and 165 genes were decreased in expression. Large differences were found in gene expression profiles under each condition, particularly with genes involved in DNA and RNA processing, iron, transposase, pilin and lipoproteins. We specifically interrogated genes encoding DNA binding regulators and iron-scavenging proteins, and identified increased expression of several iron-regulated genes, including tbpAB and fbpAB, during infection in women as compared to growth in vitro, suggesting that during infection of the genital tract in women, the gonococcus is exposed to an iron deplete environment. Collectively, we demonstrate that a large portion of the gonococcal genome is expressed and regulated during mucosal infection including genes involved in regulatory functions and iron scavenging.

No MeSH data available.


Related in: MedlinePlus

Expression of the Gonococcal mtrR / mtrCDE genes.Expression levels, reads per kilobase per million reads, (RPKM), of each of the three genes in the mtrCDE operon and the mtrR gene are shown for each of the 4 cervico-vaginal lavage samples examined as well as in the corresponding strain grown in CDM for three of subjects.
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pone.0133982.g002: Expression of the Gonococcal mtrR / mtrCDE genes.Expression levels, reads per kilobase per million reads, (RPKM), of each of the three genes in the mtrCDE operon and the mtrR gene are shown for each of the 4 cervico-vaginal lavage samples examined as well as in the corresponding strain grown in CDM for three of subjects.

Mentions: N. gonorrhoeae strains isolated recently worldwide have shown increased resistance to antibiotics [2–4]. The infecting strains in our study also were resistant to several antibiotics (S2 Table). Thus, we examined expression of genes encoding the mtrCDE efflux pump [23–26], a system that exports toxic, host-derived compounds and hydrophobic antibiotics from gonococci. MtrR, the regulatory protein which represses transcription of mtrCDE genes [27], was also examined. Expression of all genes within the mtrCDE locus was found in all 4 cervico-vaginal lavage samples (Fig 2). We observed lower levels of expression of the regulatory mtrR gene as compared to the efflux pump components for all 4 infecting strains. In Subjects 2, 3 and 4, the mtrR gene was not detected at an RPKM level of at least 10. Expression of mtrR in Subject 1 was higher than in other subjects, corresponding to a higher expression of the mtrCDE genes. Expression of the mtrA gene, which activates the mtrCDE locus [28], was also detected in Subjects 1, 2 and 4 with RPKM values of 67, 31 and 167 respectively (S1 Table—Line 262). It should be noted that many of the genes in the mtr locus also showed high expression in vitro, and that mtr genes were not specifically regulated by infection but rather showed a pattern of expression in vivo consistent with low levels of the repressor and high levels of the efflux pump genes (Fig 2).


The Gonococcal Transcriptome during Infection of the Lower Genital Tract in Women.

McClure R, Nudel K, Massari P, Tjaden B, Su X, Rice PA, Genco CA - PLoS ONE (2015)

Expression of the Gonococcal mtrR / mtrCDE genes.Expression levels, reads per kilobase per million reads, (RPKM), of each of the three genes in the mtrCDE operon and the mtrR gene are shown for each of the 4 cervico-vaginal lavage samples examined as well as in the corresponding strain grown in CDM for three of subjects.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4526530&req=5

pone.0133982.g002: Expression of the Gonococcal mtrR / mtrCDE genes.Expression levels, reads per kilobase per million reads, (RPKM), of each of the three genes in the mtrCDE operon and the mtrR gene are shown for each of the 4 cervico-vaginal lavage samples examined as well as in the corresponding strain grown in CDM for three of subjects.
Mentions: N. gonorrhoeae strains isolated recently worldwide have shown increased resistance to antibiotics [2–4]. The infecting strains in our study also were resistant to several antibiotics (S2 Table). Thus, we examined expression of genes encoding the mtrCDE efflux pump [23–26], a system that exports toxic, host-derived compounds and hydrophobic antibiotics from gonococci. MtrR, the regulatory protein which represses transcription of mtrCDE genes [27], was also examined. Expression of all genes within the mtrCDE locus was found in all 4 cervico-vaginal lavage samples (Fig 2). We observed lower levels of expression of the regulatory mtrR gene as compared to the efflux pump components for all 4 infecting strains. In Subjects 2, 3 and 4, the mtrR gene was not detected at an RPKM level of at least 10. Expression of mtrR in Subject 1 was higher than in other subjects, corresponding to a higher expression of the mtrCDE genes. Expression of the mtrA gene, which activates the mtrCDE locus [28], was also detected in Subjects 1, 2 and 4 with RPKM values of 67, 31 and 167 respectively (S1 Table—Line 262). It should be noted that many of the genes in the mtr locus also showed high expression in vitro, and that mtr genes were not specifically regulated by infection but rather showed a pattern of expression in vivo consistent with low levels of the repressor and high levels of the efflux pump genes (Fig 2).

Bottom Line: Gonorrhea is a highly prevalent disease resulting in significant morbidity worldwide, with an estimated 106 cases reported annually.A total of 140 genes were increased in expression during natural infection compared to growth in CDM, and 165 genes were decreased in expression.Large differences were found in gene expression profiles under each condition, particularly with genes involved in DNA and RNA processing, iron, transposase, pilin and lipoproteins.

View Article: PubMed Central - PubMed

Affiliation: Department of Medicine, Section of Infectious Diseases, Boston University School of Medicine, Boston, MA, United States of America; Department of Microbiology, Boston University School of Medicine, Boston, MA, United States of America.

ABSTRACT
Gonorrhea is a highly prevalent disease resulting in significant morbidity worldwide, with an estimated 106 cases reported annually. Neisseria gonorrhoeae, the causative agent of gonorrhea, colonizes and infects the human genital tract and often evades host immune mechanisms until successful antibiotic treatment is used. The alarming increase in antibiotic-resistant strains of N. gonorrhoeae, the often asymptomatic nature of this disease in women and the lack of a vaccine directed at crucial virulence determinants have prompted us to perform transcriptome analysis to understand gonococcal gene expression patterns during natural infection. We sequenced RNA extracted from cervico-vaginal lavage samples collected from women recently exposed to infected male partners and determined the complete N. gonorrhoeae transcriptome during infection of the lower genital tract in women. On average, 3.19% of total RNA isolated from female samples aligned to the N. gonorrhoeae NCCP11945 genome and 1750 gonococcal ORFs (65% of all protein-coding genes) were transcribed. High expression in vivo was observed in genes encoding antimicrobial efflux pumps, iron response, phage production, pilin structure, outer membrane structures and hypothetical proteins. A parallel analysis was performed using the same strains grown in vitro in a chemically defined media (CDM). A total of 140 genes were increased in expression during natural infection compared to growth in CDM, and 165 genes were decreased in expression. Large differences were found in gene expression profiles under each condition, particularly with genes involved in DNA and RNA processing, iron, transposase, pilin and lipoproteins. We specifically interrogated genes encoding DNA binding regulators and iron-scavenging proteins, and identified increased expression of several iron-regulated genes, including tbpAB and fbpAB, during infection in women as compared to growth in vitro, suggesting that during infection of the genital tract in women, the gonococcus is exposed to an iron deplete environment. Collectively, we demonstrate that a large portion of the gonococcal genome is expressed and regulated during mucosal infection including genes involved in regulatory functions and iron scavenging.

No MeSH data available.


Related in: MedlinePlus