Expression of soluble and functional full-length human matrix metalloproteinase-2 in Escherichia coli

Characterization of the matrix metalloproteinase-2 (MMP-2) substrates and understanding of its function remain difficult because up to date preparations containing minor amounts of other eukaryotic proteins that are co-purified with MMP-2 are still used. In this work, the expression of a soluble and functional full-length recombinant human MMP-2 (rhMMP-2) in the cytoplasm of Escherichia coli is reported, and the purification of this metalloproteinase is described. Culture of this bacterium at 18 degrees C culminated in maintenance of the soluble and functional rhMMP-2 in the soluble fraction of the E. coli lysate and its purification by affinity with gelatin-sepharose yielded approximately 0.12 mg/L of medium. Western Blotting and zymographic analysis revealed that the most abundant form was the 72-kDa MMP-2, but some gelatinolytic bands corresponding to proteins with lower molecular weight were also detected. The obtained rhMMP-2 was demonstrated to be functional in a gelatinolytic fluorimetric assay, suggesting that the purified rhMMP-2 was correctly folded. The method described here involves fewer steps, is less expensive, and is less prone to contamination with other proteinases and MMP inhibitors as compared to expression of rhMMP-2 in eukaryotic tissue culture. This protocol will facilitate the use of the full-length rhMMP-2 expressed in bacteria and will certainly help researchers to acquire new knowledge about the substrates and biological activities of this important proteinase. (C) 2011 Elsevier B.V. All rights reserved.

Bacteriocinogenic and virulence potential of Enterococcus isolates obtained from raw milk and cheese

Aims To provide molecular and phenotypical characterization of Enterococcus isolates obtained from raw milk and cheese, regarding their bacteriocinogenic and virulence activity. Methods and Results Forty-three bacteriocinogenic enterococci isolates were identified by 16s rDNA, fingerprinted by RAPD-PCR analysis and tested by PCR for the presence of genes for lantibiotics (lanM, lanB and lanC) and enterocins (entA, entB, entP, entL50AB and entAS48) and by phenotypical methods for bacteriocin production and inhibitory spectrum. Also, the virulence of the isolates was evaluated by PCR for genes gelE, hyl, asa1, esp, cylA, efaA, ace, vanA, vanB, hdc1, hdc2, tdc and odc and by phenotypical tests for gelatinase, lipase, DNAse and a- and beta-haemolysis. Most isolates (93.0%) harboured at least one lantibiotic or enterocin gene and were positive for several tested virulence genes, mainly asa1 (100%), gelE (93.0%) and efaA (83.7%). 53.5% of the isolates presented beta-haemolysis. Conclusions Enterococcus spp. isolates presented an interesting potential application for food preservation because of bacteriocin production; however, virulence-related genes were identified in all RAPD profiles. Significance and Impact of the Study The study demonstrated the contradictory characteristics of the tested Enterococcus isolates: they presented a good potential for application in food biopreservation but contained several virulence factors.

A novel set of ss-N-biaryl ether sulfonamide hydroxamates as potential MMPs inhibitors: Molecular dynamics simulations and molecular properties evaluation

Matrix metalloproteinases (MMPs) constitute a family of zinc-dependent proteases involved in the extracellular matrix degradation. MMP-2 and MMP9 are overexpressed in several human cancer types, including melanoma, thus the development of new compounds to inhibit MMPs' activity is desirable. Molecular dynamic simulation and molecular properties calculations were performed on a set of novel beta-N-biaryl ether sulfonamide-based hydroxamates, reported as MMP-2 and MMP-9 inhibitors, for providing data to develop an exploratory analysis. Thermodynamic, electronic, and steric descriptors have significantly discriminated highly active from moderately and less active inhibitors of MMP-2 whereas apparent partition coefficient at pH 1.5 was also significant for the MMP-9 data set. Compound 47 was considered an outlier in all analysis, indicating the presence of a bulky substituent group in R3 is crucial to this set of inhibitors for the establishment of molecular interactions with the S1 subsite of both enzymes, but there is a limit. (C) 2012 Wiley Periodicals, Inc.

Functional MMP-9 polymorphisms modulate plasma MMP-9 levels in multiple sclerosis patients

We have described that MMP-9 C- T-1562 and (CA)(n) polymorphisms contribute to multiple sclerosis (MS). Here, we evaluate whether plasma MMP-9 levels are related to disease severity, drug therapy resistance and polymorphisms. For sub-study 1, 36 patients with MS and 35 controls were recruited. For sub-study 2, 88 individuals (53 patients and 35 controls) were included in a cross-sectional analysis. MS patients presented higher MMP-9 activity (1.4 +/- 0.18 versus 0.93 +/- 0.18 A.U. for control, P<0.05). Drug-therapy resistant individuals exhibited increased MMP-9 activity (1.96 +/- 0.25 versus 1.21 +/- 0.09 A.U. for non-resistant patients). EDSS score was also related to MMP-9 levels. The CT + TT and HH genotypes had higher MMP-9 levels as compared to patients carrying the CC and LL Drug therapy resistance, disease severity. MMP-9 plasma activity and polymorphisms are associated with MS. (C) 2012 Elsevier B.V. All rights reserved.

Functional matrix metalloproteinase (MMP)-9 genetic variants modify the effects of hemodialysis on circulating MMP-9 levels

Background: Altered levels of matrix metalloproteinases (MMPs) and their inhibitors, the tissue inhibitors of metalloproteinases (TIMPs), are involved in cardiovascular alterations associated with end stage kidney disease (ESKD). Genetic polymorphisms in MMP-9 gene affect MMP-9 levels. We examined how MMP-9 polymorphisms and haplotypes affect the changes in plasma MMP-9 and TIMP-1 levels found in patients with ESKD undergoing hemodialysis. Methods: We studied 94 ESKD patients undergoing hemodialysis for at least 3 months. MMP-9 and TIMP-1 were measured by ELISA in plasma from blood samples collected before and after a session of hemodialysis. Genotypes for three MMP-9 polymorphisms (C-1562T, rs3918242; -90 (CA)(14-24), rs2234681; and Q279R, rs17576) were determined by Taqman (R) Allele Discrimination Assay and real-time polymerase chain reaction. Haplotype frequencies were determined with the software program PHASE 2.1. Results: Hemodialysis increased MMP-9 and TIMP-1 levels (P<0.05). Genotypes had no effects on baseline MMP-9 and TIMP-1 levels (P>0.05). Hemodialysis increased MMP-9 and TIMP-1 levels in subjects with the CC (but not CT or TT) genotype for the C-1562T polymorphism (P<0.05), and increased MMP-9 levels in subjects with the QQ (but not QR or RR) genotype for the Q279R polymorphism (P<0.05), whereas the CA(n)(14-24) polymorphism had no major effects. While MMP-9 haplotypes had no effects on baseline MMP-9 levels (P>0.05), hemodialysis increased MMP-9 levels and MMP-9/TIMP-1 ratios in subjects carrying the CLQ haplotype (P = 0.0012 and P = 0.0045, respectively). Conclusion: ESKD patients with the QQ genotype for the Q279R polymorphism or with the CLQ haplotype are exposed to more severe increases in MMP-9 levels after hemodialysis. Such patients may benefit from the use of MMP inhibitors. (C) 2012 Elsevier B.V. All rights reserved.

Matrix metalloproteinase-9 polymorphisms affect plasma MMP-9 levels and antihypertensive therapy responsiveness in hypertensive disorders of pregnancy

Abnormal matrix metalloproteinase (MMP)-9 levels may have a role in hypertensive disorders of pregnancy. We examined whether MMP-9 genetic polymorphisms (g.-1562C>T and g.-90(CA)(13-25)) modify plasma MMP-9 and tissue inhibitor of metalloproteinase (TIMP)-1 levels and the responses to antihypertensive therapy in 214 patients with preeclampsia (PE), 185 patients with gestational hypertension (GH) and a control group of 214 healthy pregnant (HP). Alleles for the g.-90(CA)(13-25) polymorphism were grouped L (low) (<21 CA repeats) or H (high) (>= 21 CA repeats). Plasma MMP-9 and TIMP-1 concentrations were measured by enzyme-linked immunosorbent assay. Plasma MMP-9 concentrations were not affected by genotypes or haplotypes in HP and PE groups, except for the g.-90(CA)(13-25) polymorphism: GH patients with the LH genotype for this polymorphism have higher MMP-9 levels than those with other genotypes. The T allele for the g.-1562C>T polymorphism and the H4 haplotype (combining T and H alleles) are associated with GH and lack of responsiveness to antihypertensive therapy in GH. The H2 haplotype (combining C and H alleles) was associated with lack of responsiveness to antihypertensive therapy in PE, but not in GH. In conclusion, our results show that MMP-9 genetic variants are associated with GH and suggest that MMP-9 haplotypes affect the responsiveness to antihypertensive therapy in hypertensive disorders of pregnancy. The Pharmacogenomics Journal (2012) 12, 489-498; doi: 10.1038/tpj.2011.31; published online 19 July 2011

Konditionale Modellsysteme zur Untersuchung der ERBB2-induzierten Tumorgenese

Konditionale Modellsysteme zur Untersuchung der ERBB2-induzierten Tumorgenese Die Rezeptor-Tyrosinkinase ERBB2 ist in einer Vielzahl epithelialer Tumore, wie Mamma- und Ovarialkarzinomen, überexprimiert. Diese erhöhte Expression korreliert mit aggressivem Tumorwachstum, verstärkter Metastasierung und schlechter Prognose für den Patienten. Zur genaueren Untersuchung molekularer Mechanismen, die zur Tumorentstehung infolge der ERBB2-Überexpression führen, wurden im Rahmen dieser Arbeit mit Hilfe des Tet-Systems induzierbare MCF-7 Zelllinien generiert. Diese exprimieren bei Gabe von Doxyzyklin ERBB2 bzw. die zum humanen ERBB2 homologe und durch Punktmutation onkogen aktivierte Rattenvariante NeuT. Nachdem die stringente Regulierbarkeit durch Doxyzyklin für die untersuchten Zellklone gezeigt werden konnte, stellte sich bei der Charakterisierung der Zelllinien heraus, dass die Induktion von ERBB2 erstaunlicherweise nicht zur Proliferation der Zellen, sondern zum Wachstumsarrest führt. Bei der Untersuchung verschiedener Zellzyklusregulatoren konnte dieser Zellzyklusarrest dem CDK-Inhibitor P21 zugeordnet werden, dessen Expression durch ERBB2 induziert wird. In P21-Antisense-Experimenten konnte nachgewiesen werden, dass P21 eine Schlüsselrolle beim ERBB2-induzierten Zellzyklusarrest spielt. Neben der Induktion von P21 und der daraus resultierenden Wachstumsinhibition zeigten die Zellen starke morphologische Veränderungen und waren positiv beim Nachweis der Seneszenz-assoziierten -Galaktosidase. Erstmals konnte gezeigt werden, dass die Induktion des Onkogens ERBB2 nicht zur Proliferation, sondern zur Aktivierung eines verfrühten Seneszenz-Programms führt, welches der Zelle Schutz gegen die Onkogeneinwirkung bietet. Bei der Untersuchung verschiedener Signaltransduktionskaskaden mit Inhibitormolekülen konnte die Aktivierung dieses Seneszenz-Programms der Stress-aktivierten Proteinkinase P38 zugeordnet werden. Zur Identifizierung von Genen, die für die ERBB2-induzierte Tumorgenese relevant sind, wurde die differenzielle Genexpression eines NeuT-Klons nach 8- bzw. 48-stündiger Induktion mit Doxyzyklin in einem cDNA-Array untersucht. Dabei zeigte sich eine besonders starke Induktion von Integrin 5 und Integrin 1, die zusammen den Fibronektinrezeptor bilden. Der funktionale Nachweis des Rezeptors in einem Adhäsionsassay demonstrierte ein stark erhöhtes Adhäsionsverhalten ERBB2-überexprimierender Zellen an Fibronektin. Bei der Untersuchung von Mamma-, Ovarial- und Endometriumkarzinomen konnte die Expression von ERBB2 mit der von Integrin 5 korreliert werden. Diese Ergebnisse machen Integrin 5 zu einem potenziellen neuen Tumormarker und Therapieziel in ERBB2-überexprimierenden Tumoren. Ein weiteres interessantes Gen, das sich im Array durch ERBB2 überexprimiert zeigte, war die Matrix-Metalloproteinase MMP-9. In einem Zymografieassay konnte die erhöhte Gelatinaseaktivität von MMP-9 in Dox-induzierten Zellen nachgewiesen werden. Der Einsatz verschiedener Signaltransduktionsinhibitoren ergab, dass auch die ERBB2-induzierte Expression von MMP-9 über die Aktivierung von P38 läuft. Bei der Suche nach weiteren MMPs, die für die ERBB2-induzierte Tumorgenese relevant sein könnten, wurde MMP-13 untersucht. Erstmals konnte gezeigt werden, dass diese Matrix-Metalloproteinase von ERBB2 induziert wird. Dieser interessante Befund wurde auch in einem anderen Zellmodell in NIH3T3 Mausfibroblasten verifiziert. Durch ihre Matrix-degradierenden Eigenschaften sind MMPs potente „Werkzeuge“ für Tumorzellen und stellen ein wichtiges Ziel zur Unterbindung der Invasion und Metastasierung dieser Zellen dar. Neben den Zellkulturarbeiten wurden im Rahmen dieser Dissertation transgene Responder-Mäuse generiert, die NeuT unter Kontrolle eines Tet-responsiven Promotors exprimieren. Von vier transgenen Gründerlinien zeigten zwei eine unerwünschte, basale NeuT-Expression, für die beiden anderen Linien konnte sowohl in MEF-Assays, als auch nach Kreuzung mit rtTA- bzw. tTA-Effektor-Mäusen eine Dox-abhängige Regulation des Transgens gezeigt werden. Die Tiere dieser Linien sollen in Zukunft mit Effektor-Mäusen gepaart werden, die den rtTA bzw. tTA spezifisch in für die ERBB2-Tumorgenese relevanten Geweben, wie Ovarial- oder Lungenepithelzellen, exprimieren. So können individuelle Tumormodelle für die verschiedenen epithelialen Tumore, bei denen die Überexpression von ERBB2 von Bedeutung ist, entwickelt und untersucht werden.

Predictive Ability of NGAL as a Marker of Renal Damage: evaluation of Multiple Clinical Settings

Introduction. Neutrophil Gelatinase-Associated Lipocalin (NGAL) belongs to the family of lipocalins and it is produced by several cell types, including renal tubular epithelium. In the kidney its production increases during acute damage and this is reflected by the increase in serum and urine levels. In animal studies and clinical trials, NGAL was found to be a sensitive and specific indicator of acute kidney injury (AKI). Purpose. The aim of this work was to investigate, in a prospective manner, whether urine NGAL can be used as a marker in preeclampsia, kidney transplantation, VLBI and diabetic nephropathy. Materials and methods. The study involved 44 consecutive patients who received renal transplantation; 18 women affected by preeclampsia (PE); a total of 55 infants weighing ≤1500 g and 80 patients with Type 1 diabetes. Results. A positive correlation was found between urinary NGAL and 24 hours proteinuria within the PE group. The detection of higher uNGAL values in case of severe PE, even in absence of statistical significance, confirms that these women suffer from an initial renal damage. In our population of VLBW infants, we found a positive correlation of uNGAL values at birth with differences in sCreat and eGFR values from birth to day 21, but no correlation was found between uNGAL values at birth and sCreat and eGFR at day 7. systolic an diastolic blood pressure decreased with increasing levels of uNGAL. The patients with uNGAL <25 ng/ml had significantly higher levels of systolic blood pressure compared with the patients with uNGAL >50 ng/ml ( p<0.005). Our results indicate the ability of NGAL to predict the delay in functional recovery of the graft. Conclusions. In acute renal pathology, urinary NGAL confirms to be a valuable predictive marker of the progress and status of acute injury.

A step forwards in immunomodulation and immunetolerance knowledge. HLA-G expression in co-cultures of peripheral blood mononuclear cells and stem cells after in vitro NGAL stimulation

NGAL (Neutrophil Gelatinase-associated Lipocalin ) is a protein of lipocalin superfamily. Recent literature focused on its biomarkers function in several pathological condition (acute and chronic kidney damage, autoimmune disease, malignancy). NGAL biological role is not well elucidated. Several are the demonstration of its bacteriostatic role. Recent papers have indeed highlight NGAL role in NFkB modulation. The aim of this study is to understand whether NGAL may exert a role in the activation (modulation) of T cell response through the regulation of HLA-G complex, a mediator of tolerance. From 8 healthy donors we obtained peripheral blood mononuclear cells (PBMCs) and we isolated by centrifugation on a Ficoll gradient. Cells were then treated with four concentrations of NGAL (40-320 ng/ml) with or without iron. We performed flow cytometry analysis and ELISA test. NGAL increased the HLA-G expression on CD4+ T cells, with an increasing corresponding to the dose. Iron effect is not of unique interpretation. NGAL adiction affects regulatory T cells increasing in vitro expansion of CD4+ CD25+ FoxP3+ cells. Neutralizing antibody against NGAL decreased HLA-G expression and reduced significantly CD4+ CD25+ FoxP3+ cells percentage. In conclusion, we provided in vitro evidence of NGAL involvement in cellular immunity. The potential role of NGAL as an immunomodulatory molecule has been evaluated: it has been shown that NGAL plays a pivotal role in the induction of immune tolerance up regulating HLA-G and T regulatory cells expression in healthy donors. As potential future scenario we highlight the in vivo role of NGAL in immunology and immunomodulation, and its possible relationship with immunosuppressive therapy efficacy, tolerance induction in transplant patients, and/or in other immunological disorders.

Detection of gelatinolytic activity in developing basement membranes of the mouse embryo head by combining sensitive in situ zymography with immunolabeling

Genetic evidence indicates that the major gelatinases MMP-2 and MMP-9 are involved in mammalian craniofacial development. Since these matrix metalloproteinases are secreted as proenzymes that require activation, their tissue distribution does not necessarily reflect the sites of enzymatic activity. Information regarding the spatial and temporal expression of gelatinolytic activity in the head of the mammalian embryo is sparse. Sensitive in situ zymography with dye-quenched gelatin (DQ-gelatin) has been introduced recently; gelatinolytic activity results in a local increase in fluorescence. Using frontal sections of wild-type mouse embryo heads from embryonic day 14.5-15.5, we optimized and validated a simple double-labeling in situ technique for combining DQ-gelatin zymography with immunofluorescence staining. MMP inhibitors were tested to confirm the specificity of the reaction in situ, and results were compared to standard SDS-gel zymography of tissue extracts. Double-labeling was used to show the spatial relationship in situ between gelatinolytic activity and immunostaining for gelatinases MMP-2 and MMP-9, collagenase 3 (MMP-13) and MT1-MMP (MMP-14), a major activator of pro-gelatinases. Strong gelatinolytic activity, which partially overlapped with MMP proteins, was confirmed for Meckel's cartilage and developing mandibular bone. In addition, we combined in situ zymography with immunostaining for extracellular matrix proteins that are potential gelatinase substrates. Interestingly, gelatinolytic activity colocalized precisely with laminin-positive basement membranes at specific sites around growing epithelia in the developing mouse head, such as the ducts of salivary glands or the epithelial fold between tongue and lower jaw region. Thus, this sensitive method allows to associate, with high spatial resolution, gelatinolytic activity with epithelial morphogenesis in the embryo.

Increased invasive potential and up-regulation of MMP-2 in MDA-MB-231 breast cancer cells expressing the beta3 integrin subunit

Integrins are a family of transmembrane adhesion receptors that might transduce signals from the extracellular matrix into the inside of cells after ligand binding. In order to investigate whether beta3 integrins expressed in tumor cells might mediate such outside-in signaling, human MDA-MB-231 breast cancer cells that were stably transfected with either beta3 integrin or mock-transfected were investigated in a matrigel degradation assay and a grafting experiment was performed on the developing chicken chorioallantoic membrane (CAM). After cultivation on matrigel for time periods between one and five days, more matrigel was digested in the wells in which beta3 integrin expressing cells were incubated than in wells of mock-transfected cells. Furthermore, extracts of beta3 integrin expressing cells contained higher levels of MMP-2 protein as determined by immunoblotting and more MMP-2 associated gelatinase activity as detected by zymography than extracts of mock-transfected cells. Matrigel degradation and gelatinase activity as well as MMP-2 expression were elevated when beta3 integrin expressing cells were incubated in the presence of the RGD peptide (mimicking an integrin ligand). After grafting on 10 day-old embryonic chicken CAM for three to five days, beta3 integrin expressing cells assembled in spheroids showed higher rates of spreading on the CAM surface and CAM invasion as well as a significant MMP-2 up-regulation compared to mock-transfected cells. The results from the in vivo and in vitro experiments allow the conclusion that the presence of beta3 integrin in MDA-MB-231 breast cancer cells induced an increased MMP-2 expression and activity that might contribute to the enhanced invasive potential observed.

Regulation of angiogenesis by interferon-beta

The purpose of these studies was to investigate the role of interferon-beta (IFN-$\beta$) in angiogenesis. IFN-$\alpha/\beta$ have been implicated in inhibiting a number of steps in the angiogenic pathway. We examined the balance of angiogenesis-regulating molecules in several systems including human infantile hemangiomas, UV-B irradiated mice, and dorsal incisional wound healing in mice. In each system, epidermal hyperplasia and cutaneous angiogenesis were directly related to the expression of positive angiogenic factors (bFGF and VEGF) and inversely related to the expression of endogenous IFN-$\beta.$ The re-expression of IFN-$\beta$ correlated with tumor regression and/or resolution of wound healing. In contrast to control mice, UV-B-induced cutaneous angiogenesis and hyperplasia persisted in IFN-$\alpha/\beta$ receptor knock-out mice. In normal mice, endogenous IFN-$\beta$ was expressed by all differentiated epithelial cells exposed to environmental stimuli. The expression of endogenous IFN-$\beta$ was necessary but insufficient for complete differentiation of epidermal keratinocytes.^ The tumor organ microenvironment can regulate angiogenesis. Human bladder carcinoma cells growing in the bladder wall of nude mice express high levels of bFGF, VEGF, and MMP-9, have higher vascular densities, and produce metastases to lymph nodes and lungs, whereas the same cells growing subcutaneously express less bFGF, VEGF, and MMP-9, have lower vascular densities, and do not metastasize. IFN-$\alpha/\beta$ was found to inhibit bFGF and MMP-9 expression both in vitro and in vivo in human bladder carcinoma cells. Systemic therapy with human IFN-$\alpha$ of human bladder cancer cells growing orthotopically in nude mice, resulted in decreased vascularity, tumorigenicity, and metastasis as compared to saline treated mice. Human bladder cancer cells resistant to the antiproliferative effects of IFN were transfected with the human IFN-$\beta$ gene. Hu-IFN-$\beta$ transfected cells expressed significantly less bFGF protein and gelatinase activity than parental or control-transfected cells and did not grow at ectopic or orthotopic sites. Collectively the data provide direct evidence that IFN-$\alpha/\beta$ can inhibit angiogenesis via down-regulation of angiogenesis-stimulating cytokines. ^

Matrix metalloproteinase inhibition lowers mortality and brain injury in experimental pneumococcal meningitis

Pneumococcal meningitis (PM) results in high mortality rates and long-lasting neurological deficits. Hippocampal apoptosis and cortical necrosis are histopathological correlates of neurofunctional sequelae in rodent models and are frequently observed in autopsy studies of patients who die of PM. In experimental PM, inhibition of matrix metalloproteinases (MMPs) and/or tumor necrosis factor (TNF)-converting enzyme (TACE) has been shown to reduce brain injury and the associated impairment of neurocognitive function. However, none of the compounds evaluated in these studies entered clinical development. Here, we evaluated two second-generation MMP and TACE inhibitors with higher selectivity and improved oral availability. Ro 32-3555 (Trocade, cipemastat) preferentially inhibits collagenases (MMP-1, -8, and -13) and gelatinase B (MMP-9), while Ro 32-7315 is an efficient inhibitor of TACE. PM was induced in infant rats by the intracisternal injection of live Streptococcus pneumoniae. Ro 32-3555 and Ro 32-7315 were injected intraperitoneally, starting at 3 h postinfection. Antibiotic (ceftriaxone) therapy was initiated at 18 h postinfection, and clinical parameters (weight, clinical score, mortality rate) were recorded. Myeloperoxidase activities, concentrations of cytokines and chemokines, concentrations of MMP-2 and MMP-9, and collagen concentrations were measured in the cerebrospinal fluid. Animals were sacrificed at 42 h postinfection, and their brains were assessed by histomorphometry for hippocampal apoptosis and cortical necrosis. Both compounds, while exhibiting disparate MMP and TACE inhibitory profiles, decreased hippocampal apoptosis and cortical injury. Ro 32-3555 reduced mortality rates and cerebrospinal fluid TNF, interleukin-1β (IL-1β) and collagen levels, while Ro 32-7315 reduced weight loss and cerebrospinal fluid TNF and IL-6 levels.

Human Urinary Composition Controls Siderocalin's Antibacterial Activity.

During Escherichia coli urinary tract infections, cells in the human urinary tract release the antimicrobial protein siderocalin (SCN; also known as lipocalin 2, neutrophil gelatinase-associated lipocalin/NGAL, or 24p3). SCN can interfere with E. coli iron acquisition by sequestering ferric iron complexes with enterobactin, the conserved E. coli siderophore. Here we find that human urinary constituents can reverse this relationship, instead making enterobactin critical for overcoming SCN-mediated growth restriction. Urinary control of SCN activity exhibits wide ranging individual differences. We used these differences to identify elevated urinary pH and aryl metabolites as key biochemical host factors controlling urinary SCN activity. These aryl metabolites are well-known products of intestinal microbial metabolism. Together, these results identify an innate antibacterial immune interaction that is critically dependent upon individualistic chemical features of human urine.

Identification and characterization of virulence factors in Enterococcus faecalis

Enterococci are one of the leading causes of nosocomial infections, and Enterococcus faecalis causes the majority of enterococcal infections. However, the mechanisms of enterococcal pathogenesis are still not yet understood. In our initial screening of E. faecalis strain OG1RF genomic libraries, autolysin and a homolog of a protein of Enterococcus faecium previously designated P54 were found to be two major antigens that reacted with human patient sera, and an antigen designated MH-1 antigen that reacted with serum from a endocarditis patient was also identified. To explore a possible role for these antigens in enterococcal infections, the genes encoding these three antigens were disrupted in Enterococcus faecalis OG1RF. ^ To explore a possible role of an E. faecalis gelatinase (encoded by gelE), which belongs to a family of Zn-metalloproteases that have been shown to be virulence factors in other organisms, in enterococcal infections, an insertion mutant was constructed in OG1RF and tested in the mouse peritonitis model. The mice infected with the gelE mutant showed a significantly prolonged survival compared to the wild type strain. To study the expression of gelE, the regions flanking gelE were sequenced. Sequence analysis of the gelE flanking regions revealed three genes (fsrA, fsrB and fsrC) upstream of gelE that show homology to the genes in a locus (agr) that globally regulates the expression of virulence factors in Staphylococcus aureus and one open reading frame (sprE) with homology to bacterial serine protease downstream of gelE. ^ In conclusion, in this study of identification of possible virulence factors in E. faecalis surface and secreted proteins, of three genes encoding antigens detected by human patient sera, none could be shown to effect virulence in the mouse peritonitis model. Inactivation of one of these antigens (autolysin) was shown to slightly increase the tolerance of E. faecalis to penicillin. A serine protease and a locus (fsr) that regulates the expression of gelE and sprE were shown to be important for enterococcal infection in the mouse peritonitis model. (Abstract shortened by UMI.)^