Gene/Protein Disease Symptom Drug Enzyme Compound
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Encapsulated Klebsiella pneumoniae is the predominant causative agent of pyogenic liver abscess, an emerging infectious disease that often complicates metastatic meningitis or endophthalmitis. The capsular polysaccharide on K. pneumoniae surface was determined as the key to virulence. Although the regulation of capsular polysaccharide biosynthesis is largely unclear, it was found that protein-tyrosine kinases and phosphatases are involved. Therefore, the identification and characterization of such kinases, phosphatases, and their substrates would advance our knowledge of the underlying mechanism in capsule formation and could contribute to the development of new therapeutic strategies. Here, we analyzed the phosphoproteome of K. pneumoniae NTUH-K2044 with a shotgun approach and identified 117 unique phosphopeptides along with 93 in vivo phosphorylated sites corresponding to 81 proteins. Interestingly, three of the identified tyrosine phosphorylated proteins, namely protein-tyrosine kinase (Wzc), phosphomannomutase (ManB), and undecaprenyl-phosphate glycosyltransferase (WcaJ), were found to be distributed in the cps locus and thus were speculated to be involved in the converging signal transduction of capsule biosynthesis. Consequently, we decided to focus on the lesser studied ManB and WcaJ for mutation analysis. The capsular polysaccharides of WcaJ mutant (WcaJY5F) were dramatically reduced quantitatively, and the LD(50) increased by 200-fold in a mouse peritonitis model compared with the wild-type strain. However, the capsular polysaccharides of ManB mutant (ManBY26F) showed no difference in quantity, and the LD(50) increased by merely 6-fold in mice test. Our study provided a clear trend that WcaJ tyrosine phosphorylation can regulate the biosynthesis of capsular polysaccharides and result in the pathogenicity of K. pneumoniae NTUH-K2044.
Mol Cell Proteomics 2009 Dec
PMID:Phosphoproteomics of Klebsiella pneumoniae NTUH-K2044 reveals a tight link between tyrosine phosphorylation and virulence. 1969 81

Mucopolysaccharidosis type IIIA (MPS IIIA) results from lack of functional sulfamidase (SGSH), a lysosomal enzyme. Its substrate, heparan sulfate, and other secondarily-stored compounds subsequently accumulate primarily within the central nervous system (CNS), resulting in progressive mental deterioration and early death. Presently there is no treatment. As a potential therapeutic strategy, recombinant human sulfamidase (rhSGSH) was administered into the CSF (via the cerebellomedullary cistern) of three adult MPS IIIA dogs either twice with a 4 day interval, or weekly for up to 4 weeks. The dogs were euthanased 24 h post-injection along with one untreated unaffected and two MPS IIIA controls. We have examined the three dimensional pattern of distribution of enzyme in the CNS and its ability to reduce primary substrate storage. High concentrations of rhSGSH protein, with up to 39-fold normal enzyme activity levels were detected within widespread areas of the CNS. RhSGSH protein was also detectable by immunohistochemistry in neurons and glia in all three enzyme-treated dogs. In both weekly-treated dogs, relative levels of a heparan sulfate-derived disaccharide, measured using tandem mass spectrometry, were lower in many brain regions when compared to untreated MPS IIIA controls. A moderately severe meningitis was also present as well as antibodies to rhSGSH in CSF/plasma. These findings demonstrate proof of principle that MPS IIIA can be treated by intracisternal enzyme replacement warranting further experiments in animals tolerant to rhSGSH. This enzyme delivery method may represent a means of treating neuropathology in MPS IIIA and other lysosomal storage disorders affecting the CNS.
Mol Genet Metab 2009 Dec
PMID:Effect of cisternal sulfamidase delivery in MPS IIIA Huntaway dogs--a proof of principle study. 1969 66

Streptococci readily colonize mucosal tissues in the nasopharynx; the respiratory, gastrointestinal, and genitourinary tracts; and the skin. Each ecological niche presents a series of challenges to successful colonization with which streptococci have to contend. Some species exist in equilibrium with their host, neither stimulating nor submitting to immune defenses mounted against them. Most are either opportunistic or true pathogens responsible for diseases such as pharyngitis, tooth decay, necrotizing fasciitis, infective endocarditis, and meningitis. Part of the success of streptococci as colonizers is attributable to the spectrum of proteins expressed on their surfaces. Adhesins enable interactions with salivary, serum, and extracellular matrix components; host cells; and other microbes. This is the essential first step to colonization, the development of complex communities, and possible invasion of host tissues. The majority of streptococcal adhesins are anchored to the cell wall via a C-terminal LPxTz motif. Other proteins may be surface anchored through N-terminal lipid modifications, while the mechanism of cell wall associations for others remains unclear. Collectively, these surface-bound proteins provide Streptococcus species with a "coat of many colors," enabling multiple intimate contacts and interplays between the bacterial cell and the host. In vitro and in vivo studies have demonstrated direct roles for many streptococcal adhesins as colonization or virulence factors, making them attractive targets for therapeutic and preventive strategies against streptococcal infections. There is, therefore, much focus on applying increasingly advanced molecular techniques to determine the precise structures and functions of these proteins, and their regulatory pathways, so that more targeted approaches can be developed.
Microbiol Mol Biol Rev 2009 Sep
PMID:Streptococcus adherence and colonization. 1972 Oct 85

Meningococcal disease is caused by Neisseria meningitidis which is associated with high morbidity and mortality. Recurrences of meningococcal infection have been observed in patients with terminal complement component defects, because of the inefficient formation of the lytic membrane attack complex (MAC), C5b-9. Complement component C7 is one of the five plasma proteins to form the MAC. The gene C7 may carry mutations that cause functional abnormalities or the mere absence of the C7 protein. More than 200 patients were screened for aberrant C7 protein by isoelectric focusing (C7 IEF). These were compared with patients in whom recurrent meningococcal infection had resulted in the diagnosis of complete C7 absence (C7Q0). A higher proportion of C7 IEF variants were found in meningitis cases compared to controls (p=0.03). In contrast to C7Q0 patients, recurrent meningococcal infection was never observed in C7 IEF cases. Whereas C7Q0 sera were defective in meningococcal serogroup B and W135 killing assays, the sera of patients with C7 IEF variants were only defective in complement-mediated killing when classical pathway activation by (endogenous) anti-meningococcal antibodies was blocked. Upon sequence analysis we characterized the genetic background of the C7*6 and C7*8 IEF pattern and identified three novel C7 gene mutations in 13 C7Q0 patients. In conclusion, C7 IEF variants can determine meningococcal killing in the early stage of infection when antibody-independent killing prevails. The results endorse the lack of clinical recurrences once antibodies are present, whereas in C7Q0 patients the anti-meningococcal antibodies may not suffice to protect from recurrent meningococcal infection.
Mol Immunol 2010 Jan
PMID:Complement factor 7 gene mutations in relation to meningococcal infection and clinical recurrence of meningococcal disease. 1993 14

There is growing evidence that certain antibiotics exert their beneficial effects not only by killing or inhibiting the growth of bacterial pathogens but also indirectly by immunomodulation. This review aims at giving an overview of the immunomodulatory properties of antibiotics in different diseases: The antiinflammatory properties of macrolides in chronic inflammatory pulmonary disorders were recognized more than 15 years ago and have been well documented in the last decade. Recent data suggest that several antibiotics such as tetracyclines and cephalosporins may have a beneficial immunomodulatory or neuroprotective effect on neuroimmunological and neurodegenerative diseases including multiple sclerosis and amyotrophic lateral sclerosis. Moreover, the non-bacteriolytic but bactericidal antibiotics rifampicin, clindamycin and aminoglycosides kill bacteria without releasing high quantities of proinflammtory cell wall components. The use of bactericidal, non-bacteriolytic protein synthesis inhibitors reduces mortality and long-term sequelae in experimental bacterial sepsis, plague and meningitis. Clinically, macrolides have been well established as an adjunctive treatment to beta-lactam antibiotics in pulmonary diseases. For other indications, appropriate clinical trials are necessary before using the immunomodulatory properties of antibiotics in clinical practice.
Curr Mol Pharmacol 2008 Jan
PMID:Immunomodulatory properties of antibiotics. 2002 25

Fructose-1, 6-bisphosphate aldolases (FBA) are cytoplasmic glycolytic enzymes, which despite lacking identifiable secretion signals, have also been found localized to the surface of several bacteria where they bind host molecules and exhibit non-glycolytic functions. Neisseria meningitidis is an obligate human nasopharyngeal commensal, which has the capacity to cause life-threatening meningitis and septicemia. Recombinant native N. meningitidis FBA was purified and used in a coupled enzymic assay confirming that it has fructose bisphosphate aldolase activity. Cell fractionation experiments showed that meningococcal FBA is localized both to the cytoplasm and the outer membrane. Flow cytometry demonstrated that outer membrane-localized FBA was surface-accessible to FBA-specific antibodies. Mutational analysis and functional complementation was used to identify additional functions of FBA. An FBA-deficient mutant was not affected in its ability to grow in vitro, but showed a significant reduction in adhesion to human brain microvascular endothelial and HEp-2 cells compared to its isogenic parent and its complemented derivative. In summary, FBA is a highly conserved, surface exposed protein that is required for optimal adhesion of meningococci to human cells.
Mol Microbiol 2010 May
PMID:The moonlighting protein fructose-1, 6-bisphosphate aldolase of Neisseria meningitidis: surface localization and role in host cell adhesion. 2019 2

Summary The pneumococcal cell surface protein PavA is a virulence factor associated with adherence and invasion in vitro. In this study we show in vivo that PavA is necessary for Streptococcus pneumoniae D39 colonization of the murine upper respiratory tract in a long-term carriage model, with PavA-deficient pneumococci being quickly cleared from nasopharyngeal tissue. In a pneumonia model, pavA mutants were not cleared from the lungs of infected mice and persisted to cause chronic infection, whereas wild-type pneumococci caused systemic infection. Hence, under the experimental conditions, PavA-deficient pneumococci appeared to be unable to seed from lung tissue into blood, although they survived in blood when administered intravenously. In a meningitis model of infection, levels of PavA-deficient pneumococci in blood and brain following intercisternal injection were significantly lower than wild type. Taken collectively these results suggest that PavA is involved in successful colonization of mucosal surfaces and in translocation of pneumococci across host barriers. Pneumococcal sepsis is a major cause of mortality worldwide so identification of factors such as PavA that are necessary for carriage and for translocation from tissue to blood is of clinical and therapeutic importance.
Mol Oral Microbiol 2010 Feb
PMID:Pneumococcal protein PavA is important for nasopharyngeal carriage and development of sepsis. 2033 93

Staphylococcus aureus is one of the most prevalent organisms responsible for nosocomial infections, and cases of community-acquired S. aureus infection have continued to increase despite widespread preventative measures. Pathologies attributed to S. aureus infection are diverse; ranging from dermal lesions to bacteremia, abscesses, and endocarditis. Reported cases of S. aureus-associated meningitis and brain abscesses have also increased in recent years, however, the precise mechanism whereby S. aureus leave the bloodstream and gain access to the central nervous system (CNS) are not known. Here we demonstrate for the first time that S. aureus efficiently adheres to and invades human brain microvascular endothelial cells (hBMEC), the single-cell layer which constitutes the blood-brain barrier (BBB). The addition of cytochalasin D, an actin microfilament aggregation inhibitor, strongly reduced bacterial invasion, suggesting an active hBMEC process is required for efficient staphylococcal uptake. Furthermore, mice injected with S. aureus exhibited significant levels of brain bacterial counts and histopathologic evidence of meningeal inflammation and brain abscess formation, indicating that S. aureus was able to breech the BBB in an experimental model of hematogenous meningitis. We found that a YpfP-deficient mutant, defective in lipoteichoic acid (LTA) membrane anchoring, exhibited a decreased ability to invade hBMEC and correlated to a reduced risk for the development of meningitis in vivo. Our results demonstrate that LTA-mediated penetration of the BBB may be a primary step in the pathogenesis of staphylococcal CNS disease.
J Mol Med (Berl) 2010 Jun
PMID:Penetration of the blood-brain barrier by Staphylococcus aureus: contribution of membrane-anchored lipoteichoic acid. 2041 83

Vancomycin is frequently added to standard therapy for pneumococcal meningitis. Although vancomycin-resistant Streptococcus pneumoniae strains have not been isolated, reports on the emergence of vancomycin-tolerant pneumococci are a cause of concern. To date, the molecular basis of vancomycin tolerance in S. pneumoniae is essentially unknown. We examined two vancomycin-tolerant clinical isolates, i.e. a purported autolysin negative (LytA(-)), serotype 23F isolate (strain S3) and the serotype 14 strain 'Tupelo', which is considered a paradigm of vancomycin tolerance. S3 was characterized here as carrying a frameshift mutation in the lytA gene encoding the main pneumococcal autolysin. The vancomycin tolerance of strain S3 was abolished by transformation to the autolysin-proficient phenotype. The original Tupelo strain was discovered to be a mixture: a strain showing a vancomycin-tolerant phenotype (Tupelo_VT) and a vancomycin-nontolerant strain (Tupelo_VNT). The two strains differed only in terms of a single mutation in the ciaH gene present in the VT strain. Most interestingly, although the vancomycin tolerance of Tupelo_VT could be overcome by increasing the LytA dosage upon transformation by a multicopy plasmid or by externally adding the autolysin, we show that vancomycin tolerance in S. pneumoniae requires the simultaneous presence of a mutated CiaH histidine kinase and capsular polysaccharide.
Mol Microbiol 2010 Aug
PMID:Vancomycin tolerance in clinical and laboratory Streptococcus pneumoniae isolates depends on reduced enzyme activity of the major LytA autolysin or cooperation between CiaH histidine kinase and capsular polysaccharide. 2059 82

Meningitis is an inflammation of the protective membranes covering the brain and spinal cord caused by bacteria, fungi, or viruses with various clinical symptoms. Although meningitis is not so prevalent, it remains the most serious contagious disease. The aim of our study was to investigate the effect of gene expressions of nitric oxide synthases (NOS) on meningitis patients. Using samples taken from 61 meningitis patients, inducible NOS, endothelial NOS (eNOS), and neuronal NOS mRNA levels were assessed in both blood and cerebrospinal fluid (CSF). A control group was constructed of 64 healthy persons. The gene expression analysis was made using real-time polymerase chain reaction method. There was no neuronal NOS expression in either group, whereas inducible NOS expression was detected in 40 blood samples and 12 CSF samples from meningitis patients. However, there were no marked differences between groups (p=0.5104). eNOS expression was detected in all blood and CSF samples, which was markedly higher in patients (p=0.0367). Because the increase in eNOS expression increases NO production, eNOS expression in meningitis patients is of great importance. This increase of eNOS in meningitis patients compared with healthy subjects may lead to novel treatments for reducing the severity of the disease.
Genet Test Mol Biomarkers 2011 Mar
PMID:mRNA expressions of inducible nitric oxide synthase, endothelial nitric oxide synthase, and neuronal nitric oxide synthase genes in meningitis patients. 2120 1


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