Proteus mirabilis Urease: Unsuspected Non-Enzymatic Properties Relevant to Pathogenicity.
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ABSTRACT:
SUBMITTER: Grahl MVC
PROVIDER: S-EPMC8268090 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:Catheter-associated urinary tract infections (CAUTIs) account for over 30% of acute nosocomial infections in the U.S. and generate $340 million in healthcare costs annually. A major causative agent of CAUTIs is Proteus mirabilis, an understudied Gram-negative pathogen noted for its ability to form urinary stones via the activity of urease. Urease mutants cannot induce stones and are attenuated in a murine UTI model, indicating this enzyme is essential to P. mirabilis pathogenesis. The ability to induce urinary stone formation requires an active urease, a nickel metalloenzyme that hydrolyzes urea. This reaction produces ammonia as a byproduct, which can serve as a nitrogen source and weak base that raises the local pH. The resulting alkalinity induces the precipitation of polyvalent cations and anions to form stones. Expression of urease genes is activated by transcriptional regulator UreR in a urea-dependent manner. Thus, urease genes are highly expressed in the urinary tract where urea is abundant (~400 mM in human urine). Production of mature urease also requires the import of nickel into the cytoplasm and its incorporation into the urease apoenzyme. Urease accessory proteins primarily acquire nickel from the Ynt transporter and facilitate the incorporation of nickel to form mature urease. P. mirabilis encodes a second, low-affinity transport system (Nik) that can provide nickel when this metal is abundant. In this study, we identified UreR as the first defined regulator of nickel transport in P. mirabilis. We also offer evidence for direct regulation of the ynt promoter by UreR. Using bioinformatics, we identified UreR-regulated urease loci in 15 Morganellaceae family species across three genera. Additionally, we located two mobilized UreR-regulated urease loci that also encode the ynt transporter, implying that UreR regulation of ynt is a conserved regulatory relationship. Our study demonstrates that UreR regulates all genes required to produce mature urease, an essential virulence factor for P. mirabilis uropathogenesis.
2024-03-25 | GSE254779 | GEO
Project description:Proteus mirabilis urease catalyzes the hydrolysis of urea, initiating the formation of urinary stones. The enzyme is critical for kidney colonization and the development of acute pyelonephritis. Urease is induced by urea and is not controlled by the nitrogen regulatory system (ntr) or catabolite repression. Purified whole-cell RNA from induced and uninduced cultures of P. mirabilis and Escherichia coli harboring cloned urease sequences was probed with a 4.2-kb BglI fragment from within the urease operon. Autoradiographs of slot blots demonstrated 4.2- and 5.8-fold increases, respectively, in urease-specific RNA upon induction with urea. Structural and accessory genes necessary for urease activity, ureD, A, B, C, E, and F, were previously cloned and sequenced (B. D. Jones and H. L. T. Mobley, J. Bacteriol. 171:6414-6422, 1989). A 1.2-kb EcoRV-BamHI restriction fragment upstream of these sequences confers inducibility upon the operon in trans. Nucleotide sequencing of this fragment revealed a single open reading frame of 882 nucleotides, designated ureR, which is transcribed in the direction opposite that of the urease structural and accessory genes and encodes a 293-amino-acid polypeptide predicted to be 33,415 Da in size. Autoradiographs of sodium dodecyl sulfate-polyacrylamide gels of [35S]methionine-labeled polypeptides obtained by in vitro transcription-translation of the PCR fragments carrying only ureR yielded a single band with an apparent molecular size of 32 kDa. Fragments carrying an in-frame deletion within ureR synthesized a truncated product. The predicted UreR amino acid sequence contains a potential helix-turn-helix motif and an associated AraC family signature and is similar to that predicted for a number of DNA-binding proteins, including E. coli proteins that regulate acid phosphatase synthesis (AppY), porin synthesis (EnvY), and rhamnose utilization (RhaR). These data suggest that UreR governs the inducibility of P. mirabilis urease.
| S-EPMC196161 | biostudies-other
Project description:Infectious urolithiasis is a type of urolithiasis, that is caused by infections of the urinary tract by bacteria producing urease such as Proteus mirabilis. Lactobacillus spp. have an antagonistic effect against many pathogens by secreting molecules, including organic acids. The aim of the study was to determine the impact of Lactobacillus strains isolated from human urine on crystallization of urine components caused by P. mirabilis by measuring bacterial viability (CFU/mL), pH, ammonia release, concentration of crystallized salts and by observing crystals by phase contrast microscopy. Moreover, the effect of lactic acid on the activity of urease was examined by the kinetic method and in silico study. In the presence of selected Lactobacillus strains, the crystallization process was inhibited. The results indicate that one of the mechanisms of this action was the antibacterial effect of Lactobacillus, especially in the presence of L. gasseri, where ten times less P. mirabilis bacteria was observed, compared to the control. It was also demonstrated that lactic acid inhibited urease activity by a competitive mechanism and had a higher binding affinity to the enzyme than urea. These results demonstrate that Lactobacillus and lactic acid have a great impact on the urinary stones development, which in the future may help to support the treatment of this health problem.
| S-EPMC10781950 | biostudies-literature
Project description:Biofilms play an important role in the antibiotic resistance of encased bacteria, and biofilm formation is regulated by quorum sensing (QS). Inhibiting the QS system may, therefore, degrade the integrity of a biofilm and expose the bacterial pathogens within it to the deleterious effects of molecules such as antibiotics. Moreover, the use of QS inhibitors (QSIs) may provide a novel approach for treating bacterial infections of aquacultures. In the present study, the bacterium Proteus mirabilis was identified as a potential producer of QSIs. Varying concentrations (0.1-1.1%) of filtrates prepared from the culture of P. mirabilis inhibited biofilm formation by the pathogens Pseudomonas aeruginosa, Vibrio harveyi and Staphylococcus aureus by as much as 58.9%, 41.5% and 41.9%, respectively. These filtrates as well as the crude aqueous extracts prepared from them increased the sensitivities of pathogens to the inhibitory effects of kanamycin. The filtrates also showed pathogenicity attenuation potential in P. aeruginosa by decreasing the production of virulence factors. Moreover, the filtrates did not influence the planktonic growth of these pathogens. The results indicate that P. mirabilis may act as a non-specific (or broad-spectrum) inhibitor of biofilm formation that will help control infectious diseases that adversely affect the aquaculture industry.
| S-EPMC5936886 | biostudies-literature
Project description:Infection and blockage of indwelling urinary catheters is significant owing to its high incidence rate and severe medical consequences. Bacterial enzymes are employed as targets for small molecular intervention in human bacterial infections. Urease is a metalloenzyme known to play a crucial role in the pathogenesis and virulence of catheter-associated Proteus mirabilis infection. Targeting urease as a therapeutic candidate facilitates the disarming of bacterial virulence without affecting bacterial fitness, thereby limiting the selective pressure placed on the invading population and lowering the rate at which it will acquire resistance. We describe the design, synthesis, and in vitro evaluation of the small molecular enzyme inhibitor 2-mercaptoacetamide (2-MA), which can prevent encrustation and blockage of urinary catheters in a physiologically representative in vitro model of the catheterized urinary tract. 2-MA is a structural analogue of urea, showing promising competitive activity against urease. In silico docking experiments demonstrated 2-MA's competitive inhibition, whilst further quantum level modelling suggests two possible binding mechanisms.
| S-EPMC7881204 | biostudies-literature
Project description:This series of microarrays compares gene expression by the bacterial pathogen Proteus mirabilis when the transcriptional regulator mrpJ is deleted or induced to levels found during experimental urinary tract infection. The enteric bacterium Proteus mirabilis is associated with a significant number of catheter-associated urinary tract infections. Strict regulation of the antagonistic processes of adhesion and motility, mediated by fimbriae and flagella, respectively, is essential for successful disease progression. Previously, the transcriptional regulator MrpJ, which is encoded by the mrp fimbrial operon, has been shown to repress both swimming and swarming motility. Here we show that MrpJ affects a wide array of cellular processes beyond adherence and motility. Microarray analysis found that expression of mrpJ mimicking expression levels that occur during UTI leads to differential expression of 217 genes related to, among others, bacterial virulence, type VI secretion and metabolism. We probed the molecular mechanism of transcriptional regulation through MrpJ using reporter assays and chromatin immunoprecipitation (ChIP). Two virulence-associated target genes, the flagellar master regulator flhDC and mrp itself, appear to be regulated through a binding site proximal to the transcriptional start, complemented by a more distantly situated enhancer site. Furthermore, an mrpJ deletion mutant colonized the bladders of mice at significantly lower levels in a transurethral model of infection. Additionally, we observe that mrpJ is widely conserved in a collection of recent clinical isolates, leading us to conclude that our results elucidate an unanticipated role of MrpJ as a global regulator of P. mirabilis virulence.
2015-04-13 | GSE63321 | GEO
Project description:Urease was purified 800-fold and partially characterized from Proteus mirabilis, the predominant microorganism associated with urinary stones. Boric acid is a rapid reversible competitive inhibitor of urease. The pH-dependence of inhibition exhibited pKa values of 6.25 and 9.3, where the latter value is probably due to the inherent pKa of boric acid. Three boronic acids also were shown to inhibit urease competitively.
| S-EPMC1148943 | biostudies-other
Project description:This series of microarrays compares gene expression by the bacterial pathogen Proteus mirabilis when the transcriptional regulator mrpJ is deleted or induced to levels found during experimental urinary tract infection. The enteric bacterium Proteus mirabilis is associated with a significant number of catheter-associated urinary tract infections. Strict regulation of the antagonistic processes of adhesion and motility, mediated by fimbriae and flagella, respectively, is essential for successful disease progression. Previously, the transcriptional regulator MrpJ, which is encoded by the mrp fimbrial operon, has been shown to repress both swimming and swarming motility. Here we show that MrpJ affects a wide array of cellular processes beyond adherence and motility. Microarray analysis found that expression of mrpJ mimicking expression levels that occur during UTI leads to differential expression of 217 genes related to, among others, bacterial virulence, type VI secretion and metabolism. We probed the molecular mechanism of transcriptional regulation through MrpJ using reporter assays and chromatin immunoprecipitation (ChIP). Two virulence-associated target genes, the flagellar master regulator flhDC and mrp itself, appear to be regulated through a binding site proximal to the transcriptional start, complemented by a more distantly situated enhancer site. Furthermore, an mrpJ deletion mutant colonized the bladders of mice at significantly lower levels in a transurethral model of infection. Additionally, we observe that mrpJ is widely conserved in a collection of recent clinical isolates, leading us to conclude that our results elucidate an unanticipated role of MrpJ as a global regulator of P. mirabilis virulence. Four biological replicates were analyzed for each set of arrays (P. mirabilis HI4320 wild type vs. ΔmrpJ, and vector pLX3607 vs. mrpJ plasmid pLX3805).
2015-04-13 | E-GEOD-63321 | biostudies-arrayexpress
Project description:Proteus mirabilis is a leading cause of catheter-associated urinary tract infections (UTIs) and urolithiasis. The transcriptional regulator MrpJ inversely modulates two critical aspects of P. mirabilis UTI progression: fimbria-mediated attachment to the urinary tract, and flagella-mediated motility. Chromatin immunoprecipitation followed by high-throughput sequencing (ChIP-seq) was used for the first time in a CAUTI pathogen to probe for in vivo direct targets of MrpJ. ChIP-seq revealed 81 78 direct MrpJ targets, including genes for motility, fimbriae and a type VI secretion system (T6SS), and the putative MrpJ binding sequence ACnCnnnnnnnGnGT.
2018-08-10 | GSE96042 | GEO
Project description:Swarming motility by the urinary tract pathogen Proteus mirabilis has been a long-studied but little understood phenomenon. On agar, a P. mirabilis colony grows outward in a bull's-eye pattern formed by consecutive waves of rapid swarming followed by consolidation into shorter cells. To examine differential gene expression in these growth phases, a microarray was constructed based on the completed genome sequence and annotation. RNA was extracted from broth-cultured, swarming, and consolidation-phase cells to assess transcription during each of these growth states. A total of 587 genes were differentially expressed in broth-cultured cells versus swarming cells, and 527 genes were differentially expressed in broth-cultured cells versus consolidation-phase cells (consolidate). Flagellar genes were highly upregulated in both swarming cells and consolidation-phase cells. Fimbriae were downregulated in swarming cells, while genes involved in cell division and anaerobic growth were upregulated in broth-cultured cells. Direct comparison of swarming cells to consolidation-phase cells found that 541 genes were upregulated in consolidate, but only nine genes were upregulated in swarm cells. Genes involved in flagellar biosynthesis, oligopeptide transport, amino acid import and metabolism, cell division, and phage were upregulated in consolidate. Mutation of dppA, oppB, and cysJ, upregulated during consolidation compared to during swarming, revealed that although these genes play a minor role in swarming, dppA and cysJ are required during ascending urinary tract infection. Swarming on agar to which chloramphenicol had been added suggested that protein synthesis is not required for swarming. These data suggest that the consolidation phase is a state in which P. mirabilis prepares for the next wave of swarming.
| S-EPMC2876570 | biostudies-literature