Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

---

Query: EC:3.1.1.79 (hormone-sensitive lipase)
2,163 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Chronic Pseudomonas aeruginosa infections lead to progressive lung tissue destruction in cystic fibrosis (CF) patients. Two bacterial cell-to-cell signals, 3-oxo-C(12)-HSL and C(4)-HSL are required for the production of several extracellular virulence factors. 3-oxo-C(12)-HSL is also required for the development of a differentiated biofilm, induces IL-8 production by epithelial cells and possesses immunomodulatory activities. These two signalling molecules are therefore believed to play a role in the pathogenesis of P. aeruginosa infections, but have never been isolated from infected human tissues. We extracted and quantified the two P. aeruginosa cell-to-cell signals from lung tissues of two CF patients infected by P. aeruginosa. 3-oxo-C(12)-HSL and C(4)-HSL were detected in the lung tissues in fmol/gram, respectively pmol/gram concentrations; the ratio C(4)-HSL/3-oxo-C(12)-HSL exceeded 100 in all tissue samples. Random Amplified Polymorphism DNA genotyping revealed that one genotype was present per lung. In vitro the P. aeruginosa isolates from the two lungs produced 3-oxo-C(12)-HSL, whereas some isolates did not produce detectable C(4)-HSL. Our results suggest that both P. aeruginosa cell-to-cell signals were produced in the lung tissue of these two cystic fibrosis patients.
...
PMID:Detection of Pseudomonas aeruginosa cell-to-cell signals in lung tissue of cystic fibrosis patients. 1185 45

Individuals with cystic fibrosis (CF) are commonly colonized with Pseudomonas aeruginosa. The chronic infections caused by P. aeruginosa are punctuated by acute exacerbations of the lung disease, which lead to significant morbidity and mortality. As regulators of virulence determinants, P. aeruginosa quorum-sensing systems may be active in the chronic lung infections associated with CF. We have examined the levels of autoinducer molecules and transcript accumulation from the bacterial populations found in the lungs of patients with CF. We detected biologically active levels of N-(3-oxododecanoyl)-L-homoserine (3-oxo-C12-HSL) and N-butyryl-L-homoserine lactone (C4-HSL) in sputum from CF patients. Interestingly, it appears that C4-HSL is less frequently detected than 3-oxo-C12-HSL in the lungs of patients with CF. We also examined the transcription of the autoinducer synthase gene lasI and showed that it is frequently expressed in the lungs of patients with CF. We observed a significant correlation between the expression of lasI and four target genes of the Las quorum-sensing system. Taken together, our results indicate that quorum-sensing systems are active and may control virulence factor expression in the lungs of patients with CF.
...
PMID:Pseudomonas aeruginosa quorum-sensing systems may control virulence factor expression in the lungs of patients with cystic fibrosis. 1189 39

Pseudomonas aeruginosa causes lethal lung infections in immunocompromised individuals such as those with cystic fibrosis. The lethality of these infections is directly associated with inflammation and lung tissue destruction. P. aeruginosa produces several acylated homoserine lactones (AHL) that are important in the regulation of bacterial virulence factors. Little is known about the effects of AHLs on human cells. In this work we report that the AHL N-(3-oxododecanoyl) homoserine lactone (3O-C(12)-HSL) from P. aeruginosa induces cyclooxygenase (Cox)-2, a seminal proinflammatory enzyme. When primary normal human lung fibroblasts were exposed to 3O-C(12)-HSL, an 8-fold induction in mRNA and a 35-fold increase in protein for Cox-2 were observed. In contrast, there was no substantial change in the expression of Cox-1. We also demonstrated that the induction of Cox-2 was regulated by 3O-C(12)-HSL activation of the transcription factor NF-kappaB. 3O-C(12)-HSL also stimulated an increase in the newly discovered inducible membrane-associated PGE synthase but had no effect on the expression of the cytosolic PGE synthase. We also demonstrate that 3O-C(12)-HSL stimulated the production of PGE(2). PGE(2) is known to induce mucus secretion, vasodilation, and edema, and acts as an immunomodulatory lipid mediator. We propose that 3O-C(12)-HSL induction of Cox-2, membrane-associated PGE synthase, and PGE(2) likely contributes to the inflammation and lung pathology induced by P. aeruginosa infections in the lung. These studies further reinforce the concept that bacterial AHLs not only regulate bacterial virulence but also stimulate the activities of eukaryotic cells important for inflammation and immune defenses.
...
PMID:The Pseudomonas autoinducer N-(3-oxododecanoyl) homoserine lactone induces cyclooxygenase-2 and prostaglandin E2 production in human lung fibroblasts: implications for inflammation. 1219 35

Acyl homoserine lactone (acyl-HSL)-mediated gene regulation has been shown to influence biofilm formation in one Burkholderia cepacia cystic fibrosis isolate, but it is not known whether this relationship is a consistent feature of the several genomic species that make up the B. cepacia complex (BCC). We screened strains belonging to genomovars I to V of the BCC for biofilm formation on an abiotic surface and for acyl-HSL synthesis. We determined that organisms from each of these genomovars were capable of biofilm formation. Similarly, acyl-HSL was synthesized by organisms from each of genomovars I to V, with most isolates producing octanoyl-HSL in greatest abundance. When biofilms were grown in Luria broth, acyl-HSL synthesis and biofilm formation appeared to be associated, but these phenotypes were independent when the biofilms were grown in basal salts containing citrate. Genomovar V strains synthesized the greatest quantities of acyl-HSL, and genomovar II and III-A strains elaborated the most abundant biofilms. Quorum sensing may play a role in BCC pathogenesis, but it may not regulate biofilm formation under all growth conditions.
...
PMID:Biofilm formation and acyl homoserine lactone production in the Burkholderia cepacia complex. 1227 Aug 26

Burkholderia cepacia and Pseudomonas aeruginosa are opportunistic pathogens that commonly cause pulmonary infections in cystic fibrosis patients and occasionally co-infect patients' lungs. Both organisms possess quorum-sensing systems dependent on N-acyl homoserine lactone (N-acyl-HSL). Cross-feeding assays demonstrated that P. aeruginosa and B. cepacia were able to utilize heterologous N-acyl-HSL signaling molecules. The ability of quorum-sensing genes from one species to complement the respective quorum-sensing mutations in the heterologous species was also examined. These studies suggest that B. cepacia CepR can use N-acyl-HSLs synthesized by RhlI and LasI and that P. aeruginosa LasR and RhlR can use N-acyl-HSLs synthesized by CepI. It is possible that a mixed bacterial population of B. cepacia and P. aeruginosa can coordinately regulate some of their virulence factors and influence the progression of lung disease due to infection with these organisms.
...
PMID:Interspecies communication between Burkholderia cepacia and Pseudomonas aeruginosa. 1238 Oct 27

Burkholderia cepacia and Pseudomonas aeruginosa often co-exist as mixed biofilms in the lungs of patients suffering from cystic fibrosis (CF). Here, we report the isolation of 13 random mini-Tn5 insertion mutants of B. cepacia H111 that are defective in biofilm formation on a polystyrene surface. We show that the screening procedure used in this study is biased towards mutants defective in the late stages of biofilm development. A detailed quantitative analysis of the biofilm structures formed by wild-type and mutant strains revealed that the isolated mutants are impaired in their abilities to develop a typical three-dimensional biofilm structure. Molecular investigations showed that the genes required for biofilm maturation fall into several classes: (i). genes encoding for surface proteins; (ii). genes involved in the biogenesis and maintenance of an integral outer membrane; and (iii). genes encoding regulatory factors. It is shown that three of the regulatory mutants produce greatly reduced amounts of N-octanoylhomoserine lactone (C8-HSL). This compound serves as the major signal molecule of the cep quorum-sensing system. As this density-dependent regulatory system is involved in the regulation of biofilm maturation, we investigated the interplay between the three regulatory genes and the quorum-sensing cascade. The results of these investigations show that the identified genes encode for regulatory elements that are positioned upstream of the cep system, indicating that the quorum-sensing system of B. cepacia is a major checkpoint for biofilm formation.
...
PMID:Genetic analysis of functions involved in the late stages of biofilm development in Burkholderia cepacia H111. 1240 18

The features of chronic airway diseases, including chronic bronchitis, cystic fibrosis, bronchiectasis, and diffuse panbronchiolitis, include chronic bacterial infection and airway obstruction by mucus. Pseudomonas aeruginosa is one of the most common pathogens in chronic lung infection, and quorum-sensing systems contribute to the pathogenesis of this disease. The quorum-sensing signal molecule [N-(3-oxododecanoyl) homoserine lactone (3O-C(12)-HSL)] not only regulates bacterial virulence but also is associated with the immune response. In this study, we investigated whether 3O-C(12)-HSL could stimulate the production of a major mucin core protein, MUC5AC. The effect of a macrolide on MUC5AC production was also studied. 3O-C(12)-HSL induced NCI-H292 cells to express MUC5AC at both the mRNA and the protein levels in time- and dose-dependent manners. A 15-membered macrolide, azithromycin, inhibited MUC5AC production that was activated by 3O-C(12)-HSL. 3O-C(12)-HSL induced extracellular signal-regulated kinase (ERK) 1/2 and I-kappa B phosphorylation in cells, and this induction was suppressed by azithromycin. 3O-C(12)-HSL-induced MUC5AC production was blocked by the ERK pathway inhibitor PD98059. Our findings suggest that the P. aeruginosa autoinducer 3O-C(12)-HSL contributes to excessive mucin production in chronic bacterial infection. Azithromycin seems to reduce this mucin production by interfering with intracellular signal transduction.
...
PMID:Azithromycin inhibits MUC5AC production induced by the Pseudomonas aeruginosa autoinducer N-(3-Oxododecanoyl) homoserine lactone in NCI-H292 Cells. 1532 11

Burkholderia cenocepacia is an opportunistic human pathogen that can aggressively colonize the cystic fibrosis lung. This organism has a LuxR/LuxI-type quorum sensing system that enables cell-cell communication via exchange of acyl homoserine lactones (AHLs). The CepR and CepI proteins constitute a global regulatory system, controlling expression of at least 40 genes, including those controlling swarming motility and biofilm formation. In this study, we isolated seven lacZ fusions in a clinical isolate of B. cenocepacia that are inducible by octanoyl-HSL. Induction of all of these genes requires CepR. The cepI promoter was tested for induction by a set of 33 synthetic autoinducers and analogues, and was most strongly induced by long-chain AHLs lacking 3-oxo substitutions. Expression of this promoter was inhibited by high concentrations of three different autoinducers, each having six-carbon acyl chains. When CepR protein was overproduced in Escherichia coli, it accumulated in a soluble form in the presence of octanoyl-HSL, but accumulated only as insoluble inclusion bodies in its absence. Purified CepR-OHL complexes bound to specific DNA sequences at the cepI and aidA promoters with high specificity. These binding sites included a 16-nucleotide imperfect dyad symmetry. Both CepR binding sites are centred approximately 44 nucleotides upstream of the respective transcription start sites.
...
PMID:Direct binding of the quorum sensing regulator CepR of Burkholderia cenocepacia to two target promoters in vitro. 1597 77

The genus Burkholderia contains over 30 species, many of which are important human pathogens. In addition to the primary pathogens Burkholderia pseudomallei and Burkholderia mallei, several species have emerged as opportunistic pathogens in persons suffering from cystic fibrosis (CF) and immunocompromised individuals. All Burkholderia species investigated so far employ quorum-sensing (QS) systems that rely on N-acyl-homoserine lactone (AHL) signal molecules to express certain phenotypic traits in a population density-dependent manner. Whilst many Burkholderia strains only contain the CepI/CepR QS system, which relies on C8-HSL, some strains, in particular isolates of B. pseudomallei and B. mallei, harbour multiple LuxI/LuxR homologues and produce numerous AHL signal molecules. Evidence has accumulated over the past few years that the QS systems operating in Burkholderia are crucial for full virulence in various animal models. However, only few QS-regulated functions required for virulence in the different infection models have so far been identified. Given the essential role of QS in the expression of pathogenic traits in Burkholderia these regulatory systems represent attractive targets for the development of novel therapeutics.
...
PMID:Quorum sensing in the genus Burkholderia. 1649 Mar 97

Pseudomonas aeruginosa is an important cause of nosocomial infections and is frequently present in the airways of cystic fibrosis patients. Quorum sensing mediates P. aeruginosa's virulence and biofilm formation through density-dependent interbacterial signaling with autoinducers. N-3-oxododecanoyl homoserine lactone (3OC12-HSL) is the major autoinducer in P. aeruginosa. We have previously shown that human airway epithelia and paraoxonases (PONs) degrade 3OC12-HSL. This study investigated the role of PON1, PON2, and PON3 in airway epithelial cell inactivation of 3OC12-HSL. All three PONs were present in murine tracheal epithelial cells, with PON2 and PON3 expressed at the highest levels. Lysates of tracheal epithelial cells from PON2, but not PON1 or PON3, knockout mice had impaired 3OC12-HSL inactivation compared with wild-type mice. In contrast, PON1-, PON2-, or PON3-targeted deletions did not affect 3OC12-HSL degradation by intact epithelia. Overexpression of PON2 enhanced 3OC12-HSL degradation by human airway epithelial cell lysates but not by intact epithelia. Finally, using a quorum-sensing reporter strain of P. aeruginosa, we found that quorum sensing was enhanced in PON2-deficient airway epithelia. In summary, these results show that loss of PON2 impairs 3OC12-HSL degradation by airway epithelial cells and suggests that diffusion of 3OC12-HSL into the airway cells can be the rate-limiting step for degradation of the molecule.
...
PMID:Paraoxonase-2 deficiency enhances Pseudomonas aeruginosa quorum sensing in murine tracheal epithelia. 1712 53


1 2 3 Next >>

---