Structural differences of neutrophil extracellular traps induced by biochemical and microbiologic stimuli under healthy and autoimmune milieus.

Neutrophil extracellular traps (NETs) are networks of decondensed chromatin loaded with antimicrobial peptides and enzymes produced against microorganisms or biochemical stimuli. Since their discovery, numerous studies made separately have revealed multiple triggers that induce similar NET morphologies allowing to classify them as lytic or non-lytic. However, the variability in NET composition depending on the inducer agent and the local milieu under similar conditions has been scarcely studied. In this work, a comparative study was conducted to evaluate structural and enzymatic divergences in NET composition induced by biochemical (phorbol myristate acetate [PMA] and hypochlorous acid [HOCl]) and microbiologic (Candida albicans, Staphylococcus aureus, and Pseudomonas aeruginosa) stimuli, along with the presence of plasma from healthy donors or patients with systemic lupus erythematosus (SLE). The results showed a differential composition of DNA and the antimicrobial peptide cathelicidin (LL37) and a variable enzymatic activity (neutrophil elastase, cathepsin G, myeloperoxidase) induced by the different stimuli despite showing morphologically similar NETs. Additionally, SLE plasma´s presence increased DNA and LL37 release during NET induction independently of the trigger stimulus but with no enzymatic activity differences. This work provides new evidence about NET composition variability depending on the inducer stimulus and the local milieu.

Cervical fluid calreticulin and cathepsin-G in pregnancies complicated by preterm prelabor rupture of membranes.

OBJECTIVE: The study aimed to determine the cervical calreticulin and cathepsin-G concentrations in pregnancies complicated by preterm prelabor rupture of membranes (PPROM) with respect to the presence of microbial invasion of the amniotic cavity (MIAC) and intra-amniotic inflammation (IAI). METHODS: Eighty women with singleton pregnancies complicated by PPROM were included in this study. Cervical and amniotic fluids were obtained at the time of admission, and concentrations of calreticulin and cathepsin-G in cervical fluid were determined using ELISA. The MIAC was defined as a positive PCR analysis for Ureaplasma species, Mycoplasma hominis, and/or Chlamydia trachomatis and/or by positivity for the 16S rRNA gene. IAI was defined as amniotic fluid bedside IL-6 concentrations ≥745 pg/mL Result: Neither women with MIAC nor with IAI had different cervical fluid concentrations of calreticulin (with MIAC: median 18.9 pg/mL vs. without MIAC: median 14.7 pg/mL, p = 0.28; with IAI: median 14.3 pg/mL vs. without IAI: median 15.6 pg/mL, p = 0.57;) or of cathepsin-G (with MIAC: median 30.7 pg/mL vs. without MIAC: median 24.7 pg/mL, p = 0.28; with IAI: median 27.3 pg/mL vs. without IAI: median 25.1 pg/mL, p = 0.80) than women without those complications. No associations between amniotic fluid IL-6 concentrations, gestational age at sampling, and cervical fluid calreticulin and cathepsin-G concentrations were found. CONCLUSIONS: Cervical fluid calreticulin and cathepsin-G concentrations did not reflect the presence of MIAC or IAI in women with PPROM.

Amniotic fluid cathepsin-G in pregnancies complicated by the preterm prelabor rupture of membranes.

OBJECTIVE: The aim of this study was to evaluate the amniotic fluid cathepsin-G concentrations in women with preterm prelabor rupture of membranes (PPROM) based on the presence of the microbial invasion of the amniotic cavity (MIAC) and/or intra-amniotic inflammation (IAI). METHODS: A total of 154 women with singleton pregnancies complicated by PPROM were included in this study. Amniotic fluid samples were obtained by transabdominal amniocentesis. Amniotic fluid cathepsin-G concentrations were assessed by ELISA. MIAC was determined using a non-cultivation approach. IAI was defined as an amniotic fluid bedside interleukin-6 concentration ≥ 745 pg/mL. RESULTS: Women with MIAC had higher amniotic fluid cathepsin-G concentrations than women without MIAC (with MIAC: median 82.7 ng/mL, versus without MIAC: median 64.7 ng/mL; p = 0.0003). Women with IAI had higher amniotic fluid cathepsin-G concentrations than women without this complication (with IAI: median 103.0 ng/mL, versus without IAI: median 66.2 ng/mL; p < 0.0001). Women with microbial-associated (with both MIAC and IAI) IAI and sterile (IAI without MIAC) IAI had higher amniotic fluid cathepsin-G concentrations than women with colonization (MIAC without IAI) and women without both MIAC and IAI (p < 0.0001). CONCLUSIONS: The presence of either microbial-associated or sterile IAI was associated with increased amniotic fluid cathepsin-G concentrations in pregnancies complicated by PPROM. Amniotic fluid cathepsin-G appears to be a potential marker of IAI.

Colorimetric Assay for the Detection of Typical Biomarkers for Periodontitis Using a Magnetic Nanoparticle Biosensor.

Periodontitis is a chronic disease which affects at least 10% of the population. If untreated, periodontitis can lead to teeth loss. Unfortunately, current diagnostic tests are limited in their sensitivity and specificity. In this study, a novel multiplex hand-held colorimetric diagnostic biosensor, using two typical inflammatory salivary biomarkers, Human Neutrophil Elastase (HNE) and Cathepsin-G, was constructed as proof of concept to potentially detect periodontitis. The biosensing method was based on the measurement of proteolytic activity using specific proteases probes. These probes consist of specific proteases substrates covalently bound to a magnetic bead from one end and to the gold sensor surface by the other end. When intact, this renders the golden sensor black. Upon proteolysis, the cleaved magnetic beads will be attracted by an external magnet revealing the golden color of the sensor surface observable by the naked eye. The biosensor was capable of specific and quantitative detection of HNE and Cathepsin-G in solution and in spiked saliva samples with a lower detection limit of 1 pg/mL and 100 fg/mL for HNE and Cathepsin-G, respectively. Examination of periodontitis patients' sample and a healthy control showed the potential of the multiplex biosensor to detect the presence of HNE and Cathepsin-G activity in situ. This approach is anticipated to be a useful biochip array amenable to low-cost point-of-care devices.

Rapid enzyme analysis as a diagnostic tool for wound infection: Comparison between clinical judgment, microbiological analysis, and enzyme analysis.

In clinical practice, diagnosis of wound infection is based on the classical clinical signs of infection. When infection is suspected, wounds are often swabbed for microbiological culturing. These methods are not accurate (clinical judgment in chronic wounds) or provide results after several days (wound swab). Therefore, there is an urgent need for an easy-to-use diagnostic tool for fast detection of wound infection, especially in chronic wounds. This study determined the diagnostic properties of the enzymes myeloperoxidase, human neutrophil elastase (HNE), lysozyme and cathepsin-G in detecting wound infection when compared to wound swabs. Both chronic and acute wounds of 81 patients were assessed through clinical judgment, enzyme analysis and wound swab. Three promising enzyme models for detecting wound infection were identified. A positive test was defined as: at least one enzyme positive after 30 minutes (model 1), lysozyme and HNE positive after 30 minutes (model 2), myeloperoxidase positive after 5 minutes, and HNE or lysozyme positive after 30 minutes (model 3). All models were significant (p≤0.001). There was no correlation between clinical judgment and wound swab, indicating the need for novel diagnostic systems. Enzyme analysis is fast, easy to use and superior to clinical judgment when compared to wound swabs.

Determination of cathepsin G in endometrial tissue using a surface plasmon resonance imaging biosensor with tailored phosphonic inhibitor.

OBJECTIVE: Cathepsin G is a serine peptidase whose physiological role is mainly associated with an early immune response, anti-microbial activity as well as platelet activation or hydrolysis of coagulation factors. In addition, since the activity of cathepsin G has been associated with the development of various pathological disorders, the measurement of its activity in patient samples is of high interest. Unfortunately, the usefulness of common immunological methods is limited, since they cannot distinguish between catalytically active and inactive protease. STUDY DESIGN: Here we present the application of recently developed Surface Plasmon Resonance-based biosensor for the detection of active cathepsin G in human endometrium samples. The key element of the system is based on the irreversible binding of cathepsin G to its specific phosphonic-type inhibitor immobilized on the surface of the gold chip. The concentration of cathepsin G was measured in tissue samples from the group of patients with endometriosis as well as in the control group. RESULTS: The level of cathepsin G ascertained in endometrium tissue samples was over twice as high for the group of patients suffering from endometriosis as compared to the control group, with the median values of 0.5 pmol/mg and 0.2 pmol/mg, respectively. CONCLUSION: The SPR sensor armed with a specific irreversible phosphonic inhibitor represents a highly useful tool for the determination of catalytically active cathepsin G concentration in endometrial tissue.

Oral microbiota and host innate immune response in bisphosphonate-related osteonecrosis of the jaw.

Bacterial biofilms have emerged as potential critical triggers in the pathogenesis of bisphosphonate (BP)-related osteonecrosis of the jaw (ONJ) or BRONJ. BRONJ lesions have shown to be heavily colonized by oral bacteria, most of these difficult to cultivate and presents many clinical challenges. The purpose of this study was to characterize the bacterial diversity in BRONJ lesions and to determine host immune response. We examined tissue specimens from three cohorts (n=30); patients with periodontal disease without a history of BP therapy (Control, n=10), patients with periodontal disease having history of BP therapy but without ONJ (BP, n=5) and patients with BRONJ (BRONJ, n=15). Denaturing gradient gel electrophoresis of polymerase chain reaction (PCR)-amplified 16S rRNA gene fragments revealed less bacterial diversity in BRONJ than BP and Control cohorts. Sequence analysis detected six phyla with predominant affiliation to Firmicutes in BRONJ (71.6%), BP (70.3%) and Control (59.1%). Significant differences (P<0.05) in genera were observed, between Control/BP, Control/BRONJ and BP/BRONJ cohorts. Enzyme-linked immunosorbent assay (ELISA) results indicated that the levels of myeloperoxidase were significantly lower, whereas interleukin-6 and tumor necrosis factor-alpha levels were moderately elevated in BRONJ patients as compared to Controls. PCR array showed significant changes in BRONJ patients with downregulation of host genes, such as nucleotide-binding oligomerization domain containing protein 2, and cathepsin G, the key modulators for antibacterial response and upregulation of secretory leukocyte protease inhibitor, proteinase 3 and conserved helix-loop-helix ubiquitous kinase. The results suggest that colonization of unique bacterial communities coupled with deficient innate immune response is likely to impact the pathogenesis of ONJ.

Surface plasmon resonance imaging biosensor for cathepsin G based on a potent inhibitor: development and applications.

A specific surface plasmon resonance imaging (SPRI) array biosensor for the determination of the enzymatically active cathepsin G (CatG) has been developed. For this purpose, a specific interaction between an inhibitor immobilized onto a chip surface and CatG in an analyzed solution was used. The MARS-115 CatG peptidyl inhibitor containing the 1-aminoalkylphosphonate diaryl ester moiety at the C terminus and N-succinamide with a free carboxylic function was synthesized and covalently immobilized onto the gold chip surface via the thiol group (cysteamine). Atomic force microscopy was used for the observation of surface changes during the subsequent steps of chip manufacture. Optimal detection conditions were chosen. High specificity of synthesized inhibitor to CatG was proved. The precision, as well as the accuracy, was found to be well suited to enzyme determination. The sensor application for the determination of CatG in white blood cells and saliva was shown for potential diagnosis of leukemia and oral cavity diseases during the early stages of those pathological states.

Application of a novel highly sensitive activity-based probe for detection of cathepsin G.

Cathepsins are crucial in antigen processing in the major histocompatibility complex class II (MHC II) pathway. Within the proteolytic machinery, three classes of proteases (i.e., cysteine, aspartic, and serine proteases) are present in the endocytic compartments. The combined action of these proteases generates antigenic peptides from antigens, which are loaded to MHC II molecules for CD4+ T cell presentation. Detection of active serine proteases in primary human antigen-presenting cells (APCs) is restricted because of the small numbers of cells isolated from the peripheral blood. For this purpose, we developed a novel highly sensitive α-aminoalkylphosphonate diphenyl ester (DAP) activity-based probe to detect the serine protease cathepsin G (CatG) in primary APCs and after Epstein-Barr virus (EBV) exposure. Although CatG activity was not altered after short-term exposure of EBV in primary myeloid dendritic cells 1 (mDC1s), the aspartic protease cathepsin D (CatD) was reduced, suggesting that EBV is responsible for mitigating the presentation of a model antigen tetanus toxoid C-fragment (TTCF) by reduction of CatD. In addition, CatG activity was reduced to background levels in B cells during cell culture; however, these findings were independent of EBV transformation. In conclusion, our activity-based probe can be used for both Western blot and 96-well-based high-throughput CatG detection when cell numbers are limited.

Acute myocardial infarction elevates serine protease activity in saliva of patients with periodontitis.

BACKGROUND AND OBJECTIVE: There are indications that acute myocardial infarction (AMI) may have an effect on the oral environment, which is reflected in the expression of salivary and gingival proteinases. According to our knowledge, no studies have been carried out to investigate the effect of AMI on the activities of two major tissue-destructive serine protease and microbial effectors, elastase and cathepsin G, produced by oral fluid polymorphonuclear granulocytes (PMN). Therefore, we compared the activities of elastase and cathepsin G in saliva from patients with AMI and from systemically healthy subjects (non-AMI) with similar periodontal conditions. MATERIAL AND METHODS: A total of 92 patients (47 AMI and 28 non-AMI patients with gingivitis or periodontitis, and 17 systemically and periodontally healthy subjects as a control group) were recruited. Clinical periodontal measurements were recorded, and stimulated whole-saliva samples were collected. The patients with AMI were clinically examined within 3-4 d after admission to the coronary care unit. The activities of saliva neutrophil elastase and cathepsin G were measured after collection, at specific time-points during incubation (from baseline to 23 h) by specific synthetic peptide substrate assays. RESULTS: The saliva of patients with AMI and periodontitis had a significant trend for the highest elastase activities among the study groups. Elastase and cathepsin G activities correlated significantly with each other in the AMI periodontitis group (r = 0.8, p < 0.01). In a logistic regression analysis, the level of salivary elastase activity associated significantly with periodontitis. CONCLUSION: AMI may be reflected in PMN serine protease elastase activity in saliva, despite its strong association with periodontitis.

Sensor materials for the detection of human neutrophil elastase and cathepsin G activity in wound fluid.

Human neutrophil elastase (HNE) and cathepsin G (CatG) are involved in the pathogenesis of a number of inflammatory disorders. These serine proteinases are released by neutrophils and monocytes in case of infection. Wound infection is a severe complication regarding wound healing causing diagnostic and therapeutic problems. In this study we have shown the potential of HNE and CatG to be used as markers for early detection of infection. Significant differences in HNE and CatG levels in infected and non-infected wound fluids were observed. Peptide substrates for these two enzymes were successfully immobilised on different surfaces, including collagen, modified collagen, polyamide polyesters and silica gel. HNE and CatG activities were monitored directly in wound fluid via hydrolysis of the chromogenic substrates. Infected wound fluids led to significant higher substrate hydrolysis compared with non-infected ones. These different approaches could be used for the development of devices which are able to detect elevated enzyme activities before manifestation of infection directly on bandages. This would allow a timely intervention by medical doctors thus preventing severe infections.

Effects of a high-protein diet on host resistance to Paracoccidioides brasiliensis in mice.

We investigated the effects of high protein intake on host resistance to Paracoccidioides brasiliensis. Two-d fasted mice were infected with P. brasiliensis and refed on diets with three different levels (54%, 20%, and 5%) of casein. The mice refed the 54% casein diet showed reduced antifungal activity in the spleen and liver as compared with the mice refed the 5% or the 20% casein diet. After infection, increases in spleen and liver mRNA levels of myeloperoxidase, cathepsin-G, and elastase-2 were more profound in the mice refed the 54% casein diet as compared with the mice refed the 5% or the 20% casein diet. Infected mice refed the 54% casein diet exhibited greater interferon (IFN)-gamma production in the spleen and liver and higher levels of thiobarbituric acid reactive substances (TBARSs) in the liver as compared with those refed the 5% casein diet. These results indicate that high protein intake impairs host resistance to P. brasiliensis.