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Serine Protease Activity (serine + protease_activity)

Distribution by Scientific Domains

Medical Sciences	50%
Life Sciences	50%

Selected Abstracts

Inhibition of fibroblast activation protein and dipeptidylpeptidase 4 increases cartilage invasion by rheumatoid arthritis synovial fibroblasts

ARTHRITIS & RHEUMATISM, Issue 5 2010
Caroline Ospelt
Objective Since fibroblasts in the synovium of patients with rheumatoid arthritis (RA) express the serine proteases fibroblast activation protein (FAP) and dipeptidylpeptidase 4 (DPP-4)/CD26, we undertook the current study to determine the functional role of both enzymes in the invasion of RA synovial fibroblasts (RASFs) into articular cartilage. Methods Expression of FAP and DPP-4/CD26 by RASFs was analyzed using fluorescence-activated cell sorting and immunocytochemistry. Serine protease activity was measured by cleavage of fluorogenic substrates and inhibited upon treatment with L-glutamyl L-boroproline. The induction and expression of matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMPs) in RASFs were detected using real-time polymerase chain reaction. Densitometric measurements of MMPs using immunoblotting confirmed our findings on the messenger RNA level. Stromal cell,derived factor 1 (SDF-1 [CXCL12]), MMP-1, and MMP-3 protein levels were measured using enzyme-linked immunosorbent assay. The impact of FAP and DPP-4/CD26 inhibition on the invasiveness of RASFs was analyzed in the SCID mouse coimplantation model of RA using immunohistochemistry. Results Inhibition of serine protease activity of FAP and DPP-4/CD26 in vitro led to increased levels of SDF-1 in concert with MMP-1 and MMP-3, which are downstream effectors of SDF-1 signaling. Using the SCID mouse coimplantation model, inhibition of enzymatic activity in vivo significantly promoted invasion of xenotransplanted RASFs into cotransplanted human cartilage. Zones of cartilage resorption were infiltrated by FAP-expressing RASFs and marked by a significantly higher accumulation of MMP-1 and MMP-3, when compared with controls. Conclusion Our results indicate a central role for the serine protease activity of FAP and DPP-4/CD26 in protecting articular cartilage against invasion by synovial fibroblasts in RA. [source]

Influenza virus RNA polymerase PA subunit is a novel serine protease with Ser624 at the active site

GENES TO CELLS, Issue 2 2001
Koyu Hara
Background Influenza virus RNA polymerase is a multifunctional enzyme that catalyses both transcription and replication of the RNA genome. The function of the influenza virus RNA polymerase PA subunit in viral replication is poorly understood, although the enzyme is known to be required for cRNA , vRNA synthesis. The protease related activity of PA has been discussed ever since protease-inducing activity was demonstrated in transfection experiments. Results PA protein was highly purified from insect cells infected with the recombinant baculovirus carrying PA cDNA, and a novel chymotrypsin-type serine protease activity was identified with the synthetic peptide, Suc-LLVY-MCA, in the PA protein. [3H]DFP was crosslinked with PA and a mutational analysis revealed that serine624 was as an active site for the protease activity. Conclusions These results constitute the demonstration of protease activity in PA subunit of the influenza virus RNA polymerase complexes. [source]

Expression of plasminogen activator inhibitor-1 and protease nexin-1 in human astrocytes: Response to injury-related factors

JOURNAL OF NEUROSCIENCE RESEARCH, Issue 11 2010
Karin Hultman
Abstract Astrocytes play a diverse role in central nervous system (CNS) injury. Production of the serine protease inhibitors (serpins) plasminogen activator inhibitor-1 (PAI-1) and protease nexin-1 (PN-1) by astrocytes may counterbalance excessive serine protease activity associated with CNS pathologies such as ischemic stroke. Knowledge regarding the regulation of these genes in the brain is limited, so the objective of the present study was to characterize the effects of injury-related factors on serpin expression in human astrocytes. Native human astrocytes were exposed to hypoxia or cytokines, including interleukin-6 (IL-6), IL-1,, tumor necrosis factor-, (TNF-,), IL-10, transforming growth factor-, (TGF-,), and TGF-, for 0,20 hr. Serpin mRNA expression and protein secretion were determined by real-time RT-PCR and ELISA, respectively. Localization of PAI-1 and PN-1 in human brain tissue was examined by immunohistochemistry. Hypoxia and all assayed cytokines induced a significant increase in PAI-1 expression, whereas prolonged treatment with IL-1, or TNF-, resulted in a significant down-regulation. The most pronounced induction of both PAI-1 and PN-1 was observed following early treatment with TGF-,. In contrast to PAI-1, the PN-1 gene did not respond to hypoxia. Positive immunoreactivity for PAI-1 in human brain tissue was demonstrated in reactive astrocytes within gliotic areas of temporal cortex. We show here that human astrocytes express PAI-1 and PN-1 and demonstrate that this astrocytic expression is regulated in a dynamic manner by injury-related factors. © 2010 Wiley-Liss, Inc. [source]

Mite serine protease activates protease-activated receptor-2 and induces cytokine release in human keratinocytes

ALLERGY, Issue 9 2009
T. Kato
Background:, House dust mites produce serine and cysteine proteases. Mite-derived proteases have been suggested to be involved in the pathogenesis of allergies; however, whether mite-derived serine protease activity can stimulate keratinocytes remains unknown. Methods:, We examined the activation of primary human keratinocytes by serine protease-rich extract of whole mite culture and compared with that by recombinant group 1 allergens (rDer f 1 and rDer p 1), which exclusively exhibit cysteine protease activity. Results:, Protease activity of whole mite culture extract (WCE), rDer f 1 and rDer p 1 induced the release of IL-8 and granulocyte-macrophage colony-stimulating factor. Protease activity of WCEs induced a significant upregulation of their mRNA expression but rDer f 1 had much less effect. Protease activity of the WCE stimulated intracellular Ca2+ mobilization but rDer f 1 and rDer p 1 did not. The mobilization induced by agonists for the human protease-activated receptor (PAR)-2, an agonist peptide or trypsin, was diminished by pre-incubation of keratinocytes with WCE. rDer f 1 inefficiently cleaved a synthetic N-terminal peptide of PAR-2 at different sites from trypsin, but the resultant peptides did not stimulate the release of interleukin-8. Conclusions:, The results suggest that mite-derived serine protease activity may contribute to the pathogenesis of atopic dermatitis by activating keratinocytes via PAR-2 activation but cysteine protease activity of Der f 1 and Der p 1 acts via another mechanism. [source]

Serine proteases from two cell types target different components of a complex that governs regulated intramembrane proteolysis of pro-,K during Bacillus subtilis development

MOLECULAR MICROBIOLOGY, Issue 3 2005
Ruanbao Zhou
Summary Upon starvation Bacillus subtilis undergoes a developmental process involving creation of two cell types, the mother cell and forespore. A signal in the form of a serine protease, SpoIVB, is secreted from the forespore and leads to regulated intramembrane proteolysis (RIP) of pro-,K, releasing active ,K into the mother cell. RIP of pro-,K is carried out by a membrane-embedded metalloprotease, SpoIVFB, which is inactive when bound by BofA and SpoIVFA. We have investigated the mechanism by which this complex is activated. By expressing components of the signalling pathway in Escherichia coli, we reconstructed complete inhibition of pro-,K RIP by BofA and SpoIVFA, and found that SpoIVB serine protease activity could partially restore RIP, apparently by targeting SpoIVFA. Pulse-chase experiments demonstrated that SpoIVFA synthesized early during B. subtilis sporulation is lost in a SpoIVB-dependent fashion, coincident with the onset of pro-,K RIP, supporting the idea that SpoIVB targets SpoIVFA to trigger RIP of pro-,K. Loss of BofA depended not only on SpoIVB, but also on CtpB, a serine protease secreted from the mother cell. CtpB appeared to cleave BofA near its C-terminus upon coexpression in E. coli, and purified CtpB degraded BofA. We propose that RIP of pro-,K involves a three-step proteolytic cascade in which SpoIVB first cleaves SpoIVFA, CtpB then cleaves BofA and finally SpoIVFB cleaves pro-,K. [source]

Inhibition of fibroblast activation protein and dipeptidylpeptidase 4 increases cartilage invasion by rheumatoid arthritis synovial fibroblasts

Abrogation of IFN-, mediated epithelial barrier disruption by serine protease inhibition

CLINICAL & EXPERIMENTAL IMMUNOLOGY, Issue 2 2005
L. E. M. Willemsen
Summary The intestinal barrier function is often impaired in a variety of diseases including chronic inflammatory bowel disease. Increased intestinal permeability during episodes of active disease correlates with destruction or rearrangement of the tight junction protein complex. IFN-, has been widely studied for its effect on barrier function and tight junction structures but its mode of action remains unclear. Since the claudin family of tight junction proteins is proposed to be involved in barrier maintenance we studied the effect of IFN-, on claudin expression in relation to epithelial barrier function. Cycloheximide and protease inhibitors were used to study mechanisms of IFN-, mediated barrier disruption. Intestinal epithelial cells were exposed to IFN-, and permeability was evaluated by horse radish peroxidase (HRP) and 4 kD FITC-dextran fluxes. Occludin and claudin-1, -2, -3, and -4 tight junction protein expression was determined by Western blotting. Occludin and claudin-2 protein expression was dramatically reduced after IFN-, exposure, which correlated with increased permeability for HRP and FITC-dextran. Interestingly, cleavage of claudin-2 was observed after incubation with IFN-,. Serine protease inhibitor AEBSF completely abrogated IFN-, mediated barrier disruption which was associated with preservation of claudin-2 expression. Moreover, IFN-, induced loss of barrier integrity was found to affect claudin-2 and occludin expression through different mechanisms. Since inhibition of serine protease activity abrogates IFN-, mediated barrier disruption this may be an important target for therapeutic intervention. [source]

Natural Occurring Polyphenols as Template for Drug Design.

CHEMICAL BIOLOGY & DRUG DESIGN, Issue 1 2009
Focus on Serine Proteases
Several major physio-pathological processes, including cancer, inflammatory states and thrombosis, are all strongly dependent upon the fine regulation of proteolytic enzyme activities, and dramatic are the consequences of unbalanced equilibria between enzymes and their cognate inhibitors. In this perspective, the discovery of small-molecule ligands able to modulate catalytic activities has a massive therapeutic potential and is a stimulating goal. Numerous recent experimental evidences revealed that proteolytic enzymes can be opportunely targeted, reporting on small ligands capable of binding to these biological macromolecules with drug-like potencies, and primarily with comparable (or even higher) efficiency with respect to their endogenous binding partner. In particular, natural occurring polyphenols and their derivatives recently disclosed these intriguing abilities, making them promising templates for drug design and development. In this review, we compared the inhibitory capacities of a set of monomeric polyphenols toward serine proteases activity, and finally summarized the data with an emphasis on the derivation of a pharmacophore model. [source]