Elastinolytic Activity Research Articles

Phylogenomic characterization of Flavobacterium psychrophilum isolates retrieved from Turkish rainbow trout farms.

Flavobacterium psychrophilum, a devastating fish pathogen, is responsible for bacterial cold-water disease (BCWD), also known as rainbow trout fry syndrome. F. psychrophilum is the main causative agent of outbreaks in rainbow trout farms, especially at early live stages. In the present study, we aimed to characterize F. psychrophilum Turkish isolates. Eighteen isolates were retrieved from BCWD outbreaks between 2014 and 2021. Invitro phenotypic characterization showed gelatin and casein hydrolysis capacities and invitro adhesion for all isolates, whereas elastinolytic activity was present for 16 of 18 isolates. We used complete genome sequencing to infer MLST-type, serotype and phylogenetic reconstruction. Strikingly, one strain isolated from Coruh trout (FP-369) belongs to ST393, a previously undescribed ST, and is phylogenetically distant from the other isolates. However, all strains retrieved from rainbow trout belong to the well-characterized clonal complex CC-ST10, 12 of 17 were tightly connected in a single cluster. Several serotypes (Types -1, -2 and -3) were represented among isolates, but no correlation was observed with geographic origins. This analysis suggests a regional dissemination of an epidemic, disease-producing bacterial population. This study provides a basis for epidemiological surveillance of isolates circulating in Turkey and phenotypic data for future molecular studies of virulence traits of this important fish pathogen.

Identification and characterization of aptameric inhibitors of human neutrophil elastase

Human neutrophil elastase (HNE) plays a pivotal role in innate immunity, inflammation and tissue remodelling. Aberrant proteolytic activity of HNE contributes to organ destruction in various chronic inflammatory diseases including emphysema, asthma, and cystic fibrosis. Therefore, elastase inhibitors could alleviate the progression of these disorders. Here, we used systematic evolution of ligands by exponential enrichment (SELEX) to develop single-stranded DNA aptamers that specifically target HNE. We determined the specificity of the designed inhibitors and their inhibitory efficacy against HNE using biochemical and in vitro methods, including an assay of neutrophil activity. Our aptamers inhibit the elastinolytic activity of HNE with nanomolar potency, and are highly specific for HNE and do not target other tested human proteases. As such, this study provides lead compounds suitable for the evaluation of their tissue-protective potential in animal models.

Altération de la perméabilité épithéliale pulmonaire par la cathepsine S au cours de la bronchopneumopathie chronique obstructive

Smoking is accountable for most of the chronic obstructive pulmonary disease (COPD) cases. COPD, which is characterized by the development of chronic bronchitis, could be associated with emphysema. In active smokers, there is an overexpression of cathepsin S, a cysteine protease, which participates in the development of emphysema via its elastinolytic activity. Likewise, we demonstrated that cathepsin S could degrade one or more protein constituents of cell junctions. This deleterious proteolytic activity leads to an alteration of the integrity of the lung epithelial barrier, which in turn could aggravate chronic inflammation and promote the exacerbation phases associated with infections.

CLINICAL AND PATHOGENESIS OVERVIEW OF MYROIDES SPP. INFECTION

The genus Myroides classified as Flavobacterium odoratum comprises non- motile ,aerobic, yellow –pigmented .They are non hemolytic on blood agar while it show a good growth on MacConkey and nutrient agar with salt tolerant up to 5% of NaCl also non fermented gram-negative rods .Members of the genus are cause many infectious disease in severely immunocompromised patient includes endocarditics urinary tract infection ,cuteneous infection ,and ventriculitis that behave as low grade opportunistic pathogens and widely distributed in the environment specially in water. Myroides spp. should be attribute among pathogens in hospitalized ,catheterized patients with wide resistant to antibiotic specially Minocycline is useful treating UTI caused by the genus . 16S ribosomal RNA(rRNA) sequencing can identified accurately the species level .In this reviews which description of dangerous infection duo to by Myroides in an immunocompromise host ,moreover reviewed the antibiotic resistance and pathogenesis. Many species of the genus Myroides were primarily taking from intestine of human. The genus Myroides includes five species : M. odoratus. , M. pelagicus, M. profundi , M. odoratimimus and M. marinus , by susceptibility to desferrioxamine . M. profundi has produced a protease Myroilysin ,with characterized as playing a role in hydrolysis of collagen through collagenase production and elastinolytic activity displaying by metalloprotease and playing important role with collagenase for hydrolysis of collagen that proven virulence of genus.

Human Neutrophil Elastase Proteolytic Activity in Ulcerative Colitis Favors the Loss of Function of Therapeutic Monoclonal Antibodies.

PurposeProteases play an essential role in the pathophysiology of inflammatory bowel disease (IBD), contributing to the intestinal mucosal lesions through the degradation of the extracellular matrix and alteration of the barrier function. Ulcerative colitis (UC) is characterized by an extensive infiltrate of neutrophils into the mucosa and hence, increased proteolytic activity. Human neutrophil elastase (HNE) is a serine protease that has been reported to be increased in UC patients’ intestinal mucosa. Based on our previous studies, we hypothesized that HNE might induce proteolytic degradation and loss of function of therapeutic monoclonal antibodies in IBD patients.Patients and MethodsElastase expression and elastinolytic activity were determined in mucosal explants from ulcerative colitis patients (n=6) and cultured ex vivo in the presence or absence of recombinant elafin. Enzymatic digestions of therapeutic monoclonal antibodies were performed using recombinant HNE and elafin. The integrity of the therapeutic antibodies was evaluated by immunoblotting and protein G binding assay, whereas their TNF-neutralizing activity was assessed with a reporter cell line.ResultsWe found that HNE and its elastinolytic activity were increased in the gut mucosa of UC patients. We also demonstrated that HNE cleaved biological drugs, impairing the TNF-α neutralizing capacity of anti-TNF monoclonal antibodies. This proteolytic degradation was inhibited by the addition of the specific inhibitor, elafin.ConclusionOur results suggest that the high level of proteolytic degradation by mucosal neutrophil elastase, along with a potential imbalance with elafin, contributes to the loss of function of biologic agents, which are currently used in patients with IBD. These findings might explain the non-responsiveness of UC patients to therapeutic monoclonal antibodies and suggest the potential beneficial concomitant use of elafin in this treatment.

Oxidation of cathepsin S by major chemicals of cigarette smoke

Lung cysteine cathepsin S (CatS) that is a potent elastase plays a deleterious role in alveolar remodeling during smoke-induced emphysema. Despite the presence of a reactive nucleophilic cysteine (Cys25) within its active site, most of its elastinolytic activity is preserved after exposure to cigarette smoke extract (CSE), a major source of sulfhydryl oxidants. This result led us to decipher CatS resistance to major and representative CSE oxidants: hydrogen peroxide, formaldehyde, acrolein and peroxynitrite. CatS was inactivated by hydrogen peroxide, peroxynitrite and acrolein in a time- and dose-dependent manner, while formaldehyde was a weaker oxidant. Hydrogen peroxide, but not CSE, formaldehyde, and peroxynitrite impaired the autocatalytic maturation of pro-CatS, whereas acrolein prevented the formation of mature CatS without hindering the initial step of the two-step autocatalytic process. Far-UV CD spectra analysis supported that oxidation by CSE and hydrogen peroxide did not led to a structural alteration of CatS, despite a notable increase of protein carbonylation, a major hallmark of oxidative damage. Evaluation of the oxidation status of Cys25 by specific biotinylated redox sensing probes suggested the formation of sulfenic acid followed by a slower conversion to sulfinic acid after incubation with hydrogen peroxide. Addition of reducing reagents (dithiothreitol, glutathione and N-acetyl cysteine) led to a partial recovery of CatS activity following incubation with CSE, hydrogen peroxide and peroxynitrite. Current results provide some mechanistic evidence of CatS stability and activity in the presence of CSE, supporting its harmful contribution to the pathophysiology of emphysema.

Murine model of invasive pulmonary Aspergillosis: Follow-up of tissue injury, fungal burden and mortality with distinct elastase production strains

To study invasive pulmonary Aspergillosis (IPA), we depleted neutrophils in mice using the monoclonal antibody anti-Gr-1/Ly-6G. Immunocompetent and neutropenic mice were infected via intratracheal with conidia of Aspergillus fumigatus clinical isolates, characterized as either higher or lower elastase producers. Neutropenic animals exhibited 100% mortality in 5 days, for both strains, and were observed survival curves overlapped, lungs with angioinvasion, rupture of bronchial and vascular walls, associated with exuberance of conidia filamentation. The immunocompetent animals infected with the lower elastase producer strain presented with upregulated inflammatory processes, and a lack of conidia filamentation in the tissue. The fungal burden in the lungs was not different in the immunocompetent and neutropenic groups. These findings confirm the protective role of neutrophils against A. fumigatus and suggest that the fungal elastinolytic activity is not a critical virulence factor but may be involved in tissue injury.

Construction of New Genetic Tools as Alternatives for Protein Overexpression in Escherichia coli and Pseudomonas aeruginosa.

Background:Pseudomonas protein expression in E. coli is known to be a setback due to significant genetic variation and absence of several genetic elements in E. coli for regulation and activation of Pseudomonas proteins. Modifications in promoter/repressor system and shuttle plasmid maintenance have made the expression of stable and active Pseudomonas protein possible in both Pseudomonas sp. and E. coli. Objectives: Construction of shuttle expression vectors for regulation and overexpression of Pseudomonas proteins in Pseudomonas sp. and E. coli. Materials and Methods:Pseudomonas-Escherichia shuttle expression vectors, pCon2(3), pCon2(3)-Kan and pCon2(3)-Zeo as well as E. coli expression vectors of pCon4 and pCon5 were constructed from pUCP19-, pSS213-, pSTBlue-1- and pPICZαA-based vectors. Protein overexpression was measured using elastase strain K as passenger enzyme in elastinolytic activity assay. Results: The integration of two series of IPTG inducible expression cassettes in pCon2(3), pCon2(3)-Kan and pCon2(3)-Zeo, each carrying an E. coli lac-operon based promoter, Plac, and a tightly regulated T7(A1/O4/O3) promoter/repressor system was performed to facilitate overexpression study of the organic solvent-tolerant elastase strain K. These constructs have demonstrated an elastinolytic fold of as high as 1464.4 % in comparison to other published constructs. pCon4 and pCon5, on the other hand, are series of pCon2(3)-derived vectors harboring expression cassettes controlled by PT7(A1/O4/O3) promoter, which conferred tight regulation and repression of basal expression due to existence of respective double operator sites, O3 and O4, and lacIq. Conclusions: The constructs offered remarkable assistance for overexpression of heterogeneous genes in Pseudomonas sp. and E. coli for downstream applications such as in industries and structural biology study.

P094. Human neutrophil elastase shows increased elastinolytic activity in ulcerative colitis and contributes to loss of function of anti-TNF-alpha agents in ulcerative colitis

P094. Human neutrophil elastase shows increased elastinolytic activity in ulcerative colitis and contributes to loss of function of anti-TNF-alpha agents in ulcerative colitis

Endothelial cells and cathepsins: Biochemical and biomechanical regulation.

Cathepsins are mechanosensitive proteases that are regulated not only by biochemical factors, but are also responsive to biomechanical forces in the cardiovascular system that regulate their expression and activity to participate in cardiovascular tissue remodeling. Their elastinolytic and collagenolytic activity have been implicated in atherosclerosis, abdominal aortic aneurysms, and in heart valve disease, all of which are lined by endothelial cells that are the mechanosensitive monolayer of cells that sense and respond to fluid shear stress as the blood flows across the surfaces of the arteries and valve leaflets. Inflammatory cytokine signaling is integrated with biomechanical signaling pathways by the endothelial cells to transcribe, translate, and activate either the cysteine cathepsins to remodel the tissue or to express their inhibitors to maintain healthy cardiovascular tissue structure. Other cardiovascular diseases should now be included in the study of the cysteine cathepsin activation because of the additional biochemical cues they provide that merges with the already existing hemodynamics driving cardiovascular disease. Sickle cell disease causes a chronic inflammation including elevated TNFα and increased numbers of circulating monocytes that alter the biochemical stimulation while the more viscous red blood cells due to the sickling of hemoglobin alters the hemodynamics and is associated with accelerated elastin remodeling causing pediatric strokes. HIV-mediated cardiovascular disease also occurs earlier in than the broader population and the influence of HIV-proteins and antiretrovirals on endothelial cells must be considered to understand these accelerated mechanisms in order to identify new therapeutic targets for prevention.

Cathepsin G activity lowers plasma LDL and reduces atherosclerosis

Cathepsin G (CatG), a serine protease present in mast cells and neutrophils, can produce angiotensin-II (Ang-II) and degrade elastin. Here we demonstrate increased CatG expression in smooth muscle cells (SMCs), endothelial cells (ECs), macrophages, and T cells from human atherosclerotic lesions. In low-density lipoprotein (LDL) receptor-deficient (Ldlr–/–) mice, the absence of CatG reduces arterial wall elastin degradation and attenuates early atherosclerosis when mice consume a Western diet for 3months. When mice consume this diet for 6months, however, CatG deficiency exacerbates atherosclerosis in aortic arch without affecting lesion inflammatory cell content or extracellular matrix accumulation, but raises plasma total cholesterol and LDL levels without affecting high-density lipoprotein (HDL) or triglyceride levels. Patients with atherosclerosis also have significantly reduced plasma CatG levels that correlate inversely with total cholesterol (r=–0.535, P<0.0001) and LDL cholesterol (r=–0.559, P<0.0001), but not with HDL cholesterol (P=0.901) or triglycerides (P=0.186). Such inverse correlations with total cholesterol (r=–0.504, P<0.0001) and LDL cholesterol (r=–0.502, P<0.0001) remain significant after adjusting for lipid lowering treatments among this patient population. Human CatG degrades purified human LDL, but not HDL. This study suggests that CatG promotes early atherogenesis through its elastinolytic activity, but suppresses late progression of atherosclerosis by degrading LDL without affecting HDL or triglycerides.

Cathepsin G deficiency reduces periaortic calcium chloride injury-induced abdominal aortic aneurysms in mice

Cathepsin G (CatG) is a serine protease that mediates angiotensin I to angiotensin II (Ang-II) conversion and is highly expressed in human abdominal aortic aneurysms (AAAs). However, it remains untested whether this protease participates in the pathogenesis of AAA. Immunofluorescent double staining demonstrated the expression of CatG in smooth muscle cells (SMCs), macrophages, and endothelial cells in human AAA lesions (n = 12) but not in AAA-free aortas (n = 10). Whereas inflammatory cytokines induced CatG expression, high glucose concentration increased CatG activity in producing Ang-II and angiotensin-converting enzyme in SMCs, which could be fully blocked by a CatG-selective inhibitor or its small interfering RNA. To test whether CatG contributes to AAA development, we generated CatG and low-density lipoprotein receptor double deficient (Ldlr(-/-)Ctsg(-/-)) mice and their littermate controls (Ldlr(-/-)Ctsg(+/+)). Absence of CatG did not affect Ang-II infusion-induced AAAs. In contrast, in Ang-II-independent AAAs induced by periaortic CaCl2 injury (n = 12 per group), CatG deficiency significantly reduced aortic diameter increase (58.33% ± 6.83% vs 31.67% ± 5.75%; P = .007), aortic lesion area (0.35 ± 0.04 mm(2) vs 0.21 ± 0.02 mm(2); P = .005), and aortic wall elastin fragmentation grade (2.75 ± 0.18 vs 1.58 ± 0.17; P = .002) along with reduced lesion collagen content grade (2.80 ± 0.17 vs 2.12 ± 0.17; P = .009) without affecting indices of lesion inflammation, angiogenesis, cell proliferation, or apoptosis. In vitro elastin degradation assays demonstrated that CaCl2-induced AAA lesions from Ldlr(-/-)Ctsg(-/-) mice contained much lower elastinolytic activity than in those from littermate control mice. Gelatin gel zymogram assay suggested that absence of CatG in CaCl2-induced AAA lesions also reduced the activity of elastinolytic matrix metalloproteinases 2 and 9. CatG may contribute to CaCl2-induced experimental AAAs directly through its elastinolytic activity and indirectly by regulating lesion matrix metalloproteinases 2 and 9 activities. Increased expression of CatG in vascular and inflammatory cells of human AAAs and its increased activity in producing Ang-II and angiotensin-converting enzyme by SMCs suggest an additional mechanism by which CatG contributes to AAA lesion progression.

A MicroRNA Processing Defect in Smokers' Macrophages Is Linked to SUMOylation of the Endonuclease DICER

Despite the fact that alveolar macrophages play an important role in smoking-related disease, little is known about what regulates their pathophysiologic phenotype. Evaluating smoker macrophages, we found significant down-regulation of multiple microRNAs (miRNAs). This work investigates the hypothesis that cigarette smoke alters mature miRNA expression in lung macrophages by inhibiting processing of primary miRNA transcripts. Studies on smoker alveolar macrophages showed a defect in miRNA maturation. Studies on the miRNA biogenesis machinery led us to focus on the cytosolic RNA endonuclease, DICER. DICER cleaves the stem-loop structure from pre-miRNAs, allowing them to dissociate into their mature 20-22-nucleotide single-stranded form. DICER activity assays confirmed impaired DICER activity following cigarette smoke exposure. Further protein studies demonstrated a decreased expression of the native 217-kDa form of DICER and an accumulation of high molecular weight forms with cigarette smoke exposure. This molecular mass shift was shown to contain SUMO moieties and could be blocked by silencing RNA directed at the primary SUMOylating ligase, Ubc9. In determining the cigarette smoke components responsible for changes in DICER, we found that N-acetylcysteine, an antioxidant and anti-aldehyde, protected DICER protein and activity from cigarette smoke extract. This massive down-regulation of miRNAs (driven in part by alterations in DICER) may be an important regulator of the disease-promoting macrophage phenotype found in the lungs of smokers.

Elastinolytic and proteolytic enzymes.

Pseudomonas aeruginosa secretes into its environment at least seven extracellular proteases: pseudolysin (LasB protease; elastase), aeruginolysin (alkaline proteinase), staphylolysin (staphylolytic endopeptidase; LasA protease), lysyl endopeptidase (protease IV; PrpL), PASP (P. aeruginosa small protease), LepA (Large ExoProtease A), and an aminopeptidase. Their action on host proteins, both individually and synergistically, plays important roles in pathogenesis of P. aeruginosa infections. Methods to measure/detect their activities are fundamental for understanding their physiological functions, roles in pathogenesis, mechanisms of action, regulation, and secretion. Most assays for determination/detection of proteolytic activity employ modified/non-modified casein or gelatin as substrates. In the quantitative assay, fragments generated from azocasein are separated from undigested substrate by trichloroacetic acid precipitation and their absorbance is measured. In non-quantitative assays, proteolytic activity is detected as clearing zones around bacterial growth or samples of culture supernatants on casein containing solid media formed due to local casein degradation. In zymography, individual proteases are detected as clear bands in gelatin/casein containing gels after SDS-PAGE separation, renaturation and protein staining. The elastinolytic capacity of P. aeruginosa is reflected by clearing zones on nutrient agar plates containing insoluble elastin instead of casein. Mueller-Hinton agar plates on which S. aureus cells are grown as a lawn are used to assess the susceptibility of S. aureus isolates to staphylolysin. A clear zone around a staphylolysin-containing sample indicates inhibition of S. aureus growth. Methods for measuring the activity of individual proteases are based on their cleavage specificity. These include assays of elastinolytic activity of pseudolysin and/or staphylolysin using elastin-Congo red as a substrate, a method for determination of staphylolytic activity in which the rate of S. aureus cell lysis is determined spectrophotometrically, and methods for determination of peptidase activity of pseudolysin, staphylolysin, lysyl endopeptidase, and the aminopeptidase. The latter methods employ chromogenic or fluorogenic peptide derivatives comprising a short amino acid sequence matching the preferred cleavage site of the protease as substrates. As only one peptide bond is cleaved in each substrate, these assays permit kinetic studies.

PWE-086 The Role of Human Neutrophil Elastase and its Inhibitor Elafin In Ulcerative Colitis

IntroductionMucosal inflammation in ulcerative colitis (UC) is characterised by an influx of neutrophils which secrete large amounts of human neutrophil elastase (HNE), causing matrix degradation. They also produce the elastase-specific...

Evaluation of the elastinolytic activity and protective effect of Leptallo I, a protein composed by metalloprotease and FA5/8C domains, from Leptospira interrogans Copenhageni

Leptospirosis is a re-emergent zoonosis, caused by pathogenic spirochetes from the genus Lepstospira. To date, there is no protein described to be involved in leptospiral hemorrhagic manifestations, although several proteases have been reported for other bacterial infections. In this study we identified 12 putative metalloproteases from the genome of Leptospira interrogans, and characterized for the first time a putative metalloprotease, here named Leptallo I, as a potential Zn2+ dependent glycylglycine protease belonging to the M23 metalloendopeptidase family. The native protein was detected in extracts from several pathogenic Leptospira species and further shown to be secreted to the culture medium. We expressed the recombinant protein and its C-terminal fragment containing the metalloprotease domain, and both presented regular secondary structures. The sera of humans with leptospirosis were able to recognize rLeptallo I, indicating that the native protein is expressed and presented to the immune system during infection. The recombinant proteins displayed a significant, though relatively low, elastinolytic activity, and the challenge of hamsters immunized with rLeptallo I conferred 33% protection, suggesting a significant importance of this protein in the pathogenesis. The elastinolytic activity may be important for leptospires–host interaction, because elastin constitutes a significant proportion of total lung and blood vessel proteins.

Sa1839 The Role of Human Neutrophil Elastase and Its Inhibitor Elafin in Ulcerative Colitis

Introduction Mucosal inflammation in ulcerative colitis (UC) is characterised by an influx of neutrophils which secrete large amounts of human neutrophil elastase (HNE), causing matrix degradation. They also produce the elastase-specific inhibitor, elafin. The aim of this study is to evaluate the relative production of elastase and elafin in active UC, and to investigate the modulatory effect of elafin on mucosal proteolytic activity ex vivo . Methods We utilised intestinal biopsies from 18 patients with active UC and 12 non-UC healthy controls. Biopsies were homogenised and lysed to extract mucosal proteins. Proteolytic activity, using elastin as a substrate, was determined. Concentrations of elafin were measured using ELISA. The effect of protease inhibitors on proteolytic activity were determined in vitro using elafin, marimastat (matrix metalloproteinase inhibitor) and the synthetic elastase inhibitor, AAPV [N-(Methoxysuccinyl)-Ala-Ala- Pro-Val Chloromethyl Ketone]. The effect of elafin on proteolytic activity ex vivo was assessed by 24 hour organ culture in the presence and absence of elafin. Unpaired Student’s t-test was used for statistical analyses. Results Mucosal protein homogenates from patients with active UC displayed higher proteolytic activity in comparison to healthy controls ( p = 0.002). Elafin levels were increased in mucosal homogenates from active UC ( p = 0.007). The addition of elafin, marimastat or AAPV, in vitro , each diminished proteolytic activity. Organ culture of UC biopsies in the presence of elafin reduces the proteolytic activity of active UC ex vivo (n.s.). Conclusion Colonic mucosal tissue from UC patients displays significantly higher elastinolytic activity in comparison to healthy controls. The addition of elafin has a restorative effect on the elastinolytic activity of UC mucosal homogenates, with the most notable effect in those tissues that had highest proteolytic activity. This occurs in the presence of significantly higher quantities of elafin in active UC mucosa. These data also show a beneficial modulatory effect of elafin on human gut tissue, suggesting a possible role for supplementary elafin in the treatment of UC. Disclosure of Interest None Declared.

Pseudomonas aeruginosa Possesses Two Putative Type I Signal Peptidases, LepB and PA1303, Each with Distinct Roles in Physiology and Virulence

Type I signal peptidases (SPases) cleave signal peptides from proteins during translocation across biological membranes and hence play a vital role in cellular physiology. SPase activity is also of fundamental importance to the pathogenesis of infection for many bacteria, including Pseudomonas aeruginosa, which utilizes a variety of secreted virulence factors, such as proteases and toxins. P. aeruginosa possesses two noncontiguous SPase homologues, LepB (PA0768) and PA1303, which share 43% amino acid identity. Reverse transcription (RT)-PCR showed that both proteases were expressed, while a FRET-based assay using a peptide based on the signal sequence cleavage region of the secreted LasB elastase showed that recombinant LepB and PA1303 enzymes were both active. LepB is positioned within a genetic locus that resembles the locus containing the extensively characterized SPase of E. coli and is of similar size and topology. It was also shown to be essential for viability and to have high sequence identity with SPases from other pseudomonads (≥ 78%). In contrast, PA1303, which is small for a Gram-negative SPase (20 kDa), was found to be dispensable. Mutation of PA1303 resulted in an altered protein secretion profile and increased N-butanoyl homoserine lactone production and influenced several quorum-sensing-controlled phenotypic traits, including swarming motility and the production of rhamnolipid and elastinolytic activity. The data indicate different cellular roles for these P. aeruginosa SPase paralogues; the role of PA1303 is integrated with the quorum-sensing cascade and includes the suppression of virulence factor secretion and virulence-associated phenotypes, while LepB is the primary SPase.

Plasma metalloproteinase levels are dysregulated in signal transducer and activator of transcription 3 mutated hyper-IgE syndrome

Plasma metalloproteinase levels are dysregulated in signal transducer and activator of transcription 3 mutated hyper-IgE syndrome

Cathepsin K Deficiency Reduces Elastase Perfusion–Induced Abdominal Aortic Aneurysms in Mice

Cathepsin K (CatK) is one of the most potent mammalian elastases. We have previously shown increased expression of CatK in human abdominal aortic aneurysm (AAA) lesions. Whether this protease participates directly in AAA formation, however, remains unknown. Mouse experimental AAA was induced with aortic perfusion of a porcine pancreatic elastase. Using this experimental model, we demonstrated that absence of CatK prevented AAA formation in mice 14 days postperfusion. CatK deficiency significantly reduced lesion CD4(+) T-cell content, total lesion and medial cell proliferation and apoptosis, medial smooth muscle cell (SMC) loss, elastinolytic CatL and CatS expression, and elastin fragmentation, but it did not affect AAA lesion Mac-3(+) macrophage accumulation or CD31(+) microvessel numbers. In vitro studies revealed that CatK contributed importantly to CD4(+) T-cell proliferation, SMC apoptosis, and other cysteinyl cathepsin and matrix metalloproteinase expression and activities in SMCs and endothelial cells but played negligible roles in microvessel growth and monocyte migration. AAA lesions from CatK-deficient mice showed reduced elastinolytic cathepsin activities compared with those from wild-type control mice. This study demonstrates that CatK plays an essential role in AAA formation by promoting T-cell proliferation, vascular SMC apoptosis, and elastin degradation and by affecting vascular cell protease expression and activities.