Project description:BackgroundFor most pathogens, iron (Fe) homeostasis is crucial for maintenance within the host and the ability to cause disease. The primary transcriptional regulator that controls intracellular Fe levels is the Fur (ferric uptake regulator) protein, which exerts its action on transcription by binding to a promoter-proximal sequence termed the Fur box. Fur-regulated transcriptional responses are often fine-tuned at the post-transcriptional level through the action of small regulatory RNAs (sRNAs). Consequently, identifying sRNAs contributing to the control of Fe homeostasis is important for understanding the Fur-controlled bacterial Fe-response network.ResultsIn this study, we sequenced size-selected directional libraries representing sRNA samples from Neisseria gonorrhoeae strain FA 1090, and examined the Fe- and temporal regulation of these sRNAs. RNA-seq data for all time points identified a pool of at least 340 potential sRNAs. Differential analysis demonstrated that expression appeared to be regulated by Fe availability for at least fifteen of these sRNAs. Fourteen sRNAs were induced in high Fe conditions, consisting of both cis and trans sRNAs, some of which are predicted to control expression of a known virulence factor, and one SAM riboswitch. An additional putative cis-acting sRNA was repressed by Fe availability. In the pathogenic Neisseria species, one sRNA that contributes to Fe-regulated post-transcriptional control is the Fur-repressible sRNA NrrF. The expression of five Fe-induced sRNAs appeared to be at least partially controlled by NrrF, while the remainder was expressed independently of NrrF. The expression of the 14 Fe-induced sRNAs also exhibited temporal control, as their expression levels increased dramatically as the bacteria entered stationary phase.ConclusionsHere we report the temporal expression of Fe-regulated sRNAs in N. gonorrhoeae FA 1090 with several appearing to be controlled by the Fe-repressible sRNA NrrF. Temporal regulation of these sRNAs suggests a regulatory role in controlling functions necessary for survival, and may be important for phenotypes often associated with altered growth rates, such as biofilm formation or intracellular survival. Future functional studies will be needed to understand how these regulatory sRNAs contribute to gonococcal biology and pathogenesis.
Project description:Neisseria gonorrhoeae, the etiologic agent of gonorrhea, is frequently asymptomatic in women, often leading to chronic infections. One factor contributing to this may be biofilm formation. N. gonorrhoeae can form biofilms over glass and plastic surfaces. There is also evidence that biofilm formation may occur during natural cervical infection. To further study the mechanism of this biofilm formation, transcriptional profiles of N. gonorrhoeae biofilm were compared to planktonic profiles. Biofilm RNA was extracted from N. gonorrhoeae 1291 grown for 48 hours in continuous flow chambers over glass. Planktonic RNA was extracted from the biofilm runoff. When biofilm was compared to planktonic growth, 3.8 % of the genome was differentially regulated. Genes highly up-regulated in biofilm included aniA, norB, and ccp, which play critical roles in anaerobic metabolism and oxidative stress tolerance. Down-regulated genes included the nuo gene cluster (NADH dehydrogenase) and the cytochrome bcI complex, which are involved in aerobic respiration and are thought to contribute to endogenous oxidative stress. Furthermore, we determined that aniA, ccp, and norB insertional mutants are attenuated for biofilm formation over glass and transformed human cervical epithelial cells (THCEC). This data suggests that biofilm formation could minimize oxidative stress during cervical infection and allow N. gonorrhoeae to maintain a nitric oxide steady state that may be anti-inflammatory.
Project description:Gonorrhea occurs at high incidence worldwide and has a major impact on reproductive and neonatal health worldwide. Alarmingly, with each new antibiotic introduced for gonorrhea, resistance has emerged, including resistance to penicillin, tetracycline, fluoroquinolones, and recently the third-generation cephalosporins. Treatment options are currently seriously limited and the development of a gonorrhea vaccine is a critical, longterm solution to this problem. Progress on gonorrhea vaccines has been slow, however, in part due to the high number of surface molecules in Neisseria gonorrhoeae (GC) that undergo phase or antigenic variation and a lack of understanding of protective responses. Gonorrhea vaccine development can therefore benefit from a comprehensive, unbiased approach for antigen discovery. Here we identified cell envelop proteins from Neisseria gonorrhoeae exposed to physiology relevant conditions: presence of human serum, iron limitation and anaerobic growth.
Project description:Neisseria gonorrhoeae is the causative agent of gonorrhea, a leading sexually transmitted disease with severe complications on reproductive health. The U.S. Centers for Disease Control and Prevention has categorized the public health threat induced by N. gonorrhoeae as “urgent”, due to the ease of transmission and the fast emergence of multi-drug resistant strains. The need for development of vaccines and understanding the underlying factors leading to antibiotic resistance is of utmost importance. The proteomic profiles of the 14 WHO N. gonorrhoeae reference strains have been compared to the WHO F reference strain using a mass spectrometry with tandem mass tags (TMT) labeling to analyze the cell envelope and the cytoplasmic fractions extracted from each strain. Identifying novel vaccine candidates and proteomic signatures for antimicrobial resistance will further our understanding of N. gonorrhoeae proteotypes, in relationship to their respective genotypes and phenotypes, and provide deep insights that will impact the development of preventive and therapeutic tools to combat gonorrhea.
Project description:Neisseria gonorrhoeae (GC) is a human-specific pathogen, and the agent of a sexually transmitted disease, gonorrhea. There is a critical need for new approaches to study and treat GC infections because of the growing threat of multidrug-resistant isolates and the lack of a vaccine. Despite the implied role of the GC cell envelope and membrane vesicles in colonization and infection of human tissues and cell lines, comprehensive studies have not been undertaken to elucidate their constituents. Accordingly, in pursuit of novel molecular therapeutic targets, we have applied isobaric tagging for absolute quantification coupled with liquid chromatography and mass spectrometry for proteome quantitative analyses. Mining the proteome of cell envelopes and native membrane vesicles revealed 533 and 168 common proteins, respectively, in analyzed GC strains FA1090, F62, MS11, and 1291.