Neutrophil Serine Proteases Research Articles

Pharmacological inhibition of the cysteine protease cathepsin C improves graft function after heart transplantation in rats

BackgroundHeart transplantation (HTX) is the standard treatment for end-stage heart failure. However, reperfusion following an ischemic period can contribute to myocardial injury. Neutrophil infiltration, along with the subsequent release of tissue-degrading neutrophil elastase (NE)-related serine proteases and oxygen-derived radicals, is associated with adverse graft outcomes. The inhibition of cathepsin C (CatC) has been shown to block NE-related protease activation. We hypothesized that the CatC inhibitor BI-9740 improves graft function after HTX.MethodsIn a rat model of HTX, the recipient Lewis rats were orally administered with either a placebo (n = 12) or BI-9740 (n = 11, 20 mg/kg) once daily for 12 days. Donor hearts from untreated Lewis rats were explanted, preserved in a cardioplegic solution, and subsequently heterotopically implanted. In vivo left-ventricular (LV) graft function was assessed after 1 h of reperfusion. The proteolytic activity of neutrophil serine proteases was determined in bone marrow lysates from BI-9740-treated and control rats. Additionally, myocardial morphological changes were examined, and heart samples underwent immunohistochemistry and western blot analysis.ResultsThe NE-related proteolytic activity in bone marrow cell lysates was markedly decreased in the BI-9740-treated rats compared to those of the placebo group. Histopathological lesions, elevated CatC and myeloperoxidase-positive cell infiltration, and nitrotyrosine immunoreactivity with an increased number of poly(ADP-ribose) polymerase (PARP)-1-positive cells were lowered in the hearts of animals treated with BI-9740 compared to placebo groups. Regarding the functional parameters of the implanted graft, improvements were observed in both systolic function (LV systolic pressure 110 ± 6 vs 74 ± 6 mmHg; dP/dtmax 2782 ± 149 vs 2076 ± 167 mmHg/s, LV developed pressure, at an intraventricular volume of 200 µl, p < 0.05) and diastolic function in the hearts of BI-9740 treated animals compared with those receiving the only placebo. Furthermore, the administration of BI-9740 resulted in a shorter graft re-beating time compared to the placebo group. However, this study did not provide evidence of DNA fragmentation, the generation of both superoxide anions and hydrogen peroxide, correlating with the absence of protein alterations related to apoptosis, as evidenced by western blot in grafts after HTX.ConclusionsWe provided experimental evidence that pharmacological inhibition of CatC improves graft function following HTX in rats.

In-silico Screening of Potential Phytochemicals against Extracellular Adherence (Eap) Protein of Staphylococcus aureus from Indian Medicinal Plants

Background: Staphylococcus aureus is a threat to human health, it colonizes one-third of the human population via skin or nose and deeper intrusions into tissues have catastrophic consequences. The bacterium secretes virulence proteins like CHIP and SCIN and extracellular adhesins like extracellular adherence (Eap) proteins. Eap and its functionally orphan homologs, EapH1 and EapH2; are a class of secreted proteins that inhibit neutrophil serine proteases such as neutrophil elastase (HNE) that is linked to tissue degradation in a variety of disease conditions including inflammatory disorders. Commercial drugs used against S.aureus such as Nafcillin, Pefloxacin, etc. have been known to have negative effects and are not recommended for children, the elderly, or pregnant women. Objective: The current research focuses on discovering phytochemicals found in Indian medicinal herbs that have been used as spices for ages and are already beneficial against a variety of illnesses and ailments to be used against Eap proteins. Method: Molecular docking;absorption, distribution, metabolism, excretion, toxicity (ADMET) analysis and Simulation were performed to see if these phytochemicals interact with the active site residues of Eap proteins and function as competitive inhibitors of NE and to know their drug like properties and gather information about the system dynamics. 19 phytochemicals were selected from receptor-ligand docking. The selected molecules were pharmacologically tested through Lipinski’s analysis; to know their ability for being formulated into drugs. ADMET analysis was carried out to define the biological characteristic of phytochemicals inside the living body. The phytochemicals with the best docking score and drug likeliness were analysed by Molecular Simulation to observe the fluctuation of participating and interacting amino acids with Eaph1 and Eaph2 respectively. Result: Among the nineteen phytochemicals that were chosen for docking only the best eleven interactions were chosen for ADMET analysis. The top hit phytochemicals for Eaph1 and Eaph2 were Curcumin and Eugenol respectively, which was well demonstrated by Molecular dynamic simulation. Conclusion: The present study has established the hypothesis that phytochemicals have a scope to replace commercial drugs against the Eap virulence system of Staphylococcus aureus

Brensocatib (an oral, reversible inhibitor of dipeptidyl peptidase-1) attenuates disease progression in two animal models of rheumatoid arthritis.

Rheumatoid arthritis (RA) is a painful and incurable disease characterized by chronic joint inflammation and a progressive destruction of cartilage and bone. Although current treatments have improved clinical outcomes for some patients, the high relapse rates and sizeable proportion of non-responders emphasize the need for further research. Arthritic joints are massively infiltrated by neutrophils, which influence inflammatory and immune processes by releasing cytokines, chemokines, eicosanoids, and neutrophil serine proteases (NSPs) - all of which are known to contribute to RA initiation and progression. Active NSPs are generated from zymogens at the promyelocytic stage of neutrophil differentiation under the action of dipeptidyl peptidase 1 (DPP-1) and DPP-1 knockout mice are resistant to the development of arthritis. Thus, DPP-1 inhibition represents a promising therapeutic approach in RA. In this study, we assessed the efficacy of a potent and highly selective DPP-1 inhibitor, brensocatib, in two well established RA models - rat collagen-induced arthritis (CIA) and mouse collagen antibody-induced arthritis (CAIA). In both models, brensocatib at 3 and 30 mg/kg/day significantly reduced bone marrow NSP levels, in keeping with prior pharmacodynamic studies in rodents. More importantly, brensocatib treatment significantly improved disease score at both dosages in both rodent models. In the mouse CAIA model, brensocatib even proved at least as potent as anti-TNF antibodies in diminishing both the histopathological score and neutrophil infiltration into arthritic joints. Together, these results show that brensocatib alters RA disease progression in rodents and supports the need for its further evaluation as a potential therapeutic option, or to complement existing RA treatments.

E-64c-Hydrazide Based Cathepsin C Inhibitors: Optimizing the Interactions with the S1'-S2' Area.

The zymogens of the neutrophil serine proteases elastase, proteinase 3, and cathepsin G are converted proteolytically into their pro-inflammatory active forms by the action of cathepsin C. The inhibition of this cysteine protease therefore is an interesting therapeutic approach for the treatment of inflammatory disorders with a high neutrophil burden such as COPD. Based on E-64c-hydrazide as lead structure, we have recently developed a covalently acting cathepsin C inhibitor using a n-butyl residue attached at the amine nitrogen of the hydrazide moiety to efficiently address the deep hydrophobic S2 pocket. To further optimize the affinity and selectivity profile of this inhibitor, the S1'-S2' area was now investigated by a combinatorial approach, showing that Nle-tryptamide is a ligand superior to the initially used Leu-isoamylamide. Using the neutrophil precursor line U937 as a cell culture model, this optimized inhibitor blocks the intracellular cathepsin C activity and thereby suppresses the activation of neutrophil elastase.

The pharmacokinetic profile of brensocatib and its effect on pharmacodynamic biomarkers including NE, PR3, and CatG in various rodent species.

Brensocatib is a novel, oral, selective, reversible inhibitor of dipeptidyl peptidase 1 (DPP1), which activates several neutrophil serine proteases (NSPs), including neutrophil elastase (NE), proteinase 3 (PR3), and cathepsin G (CatG) in the bone marrow during the early stage of neutrophil maturation. These NSPs are associated with pathogen destruction and inflammatory mediation; their dysregulated activation can result in excess secretion of active NSPs causing damaging inflammation and contributing to neutrophil-mediated inflammatory and autoimmune diseases. Pharmacological inhibition of DPP1 in the bone marrow could therefore represent an attractive strategy for these neutrophil-driven diseases. A completed Phase 2 trial in non-cystic fibrosis bronchiectasis patients (ClinicalTrials.gov number NCT03218917; EudraCT number: 2017-002533-32) indeed demonstrated that administration of brensocatib attenuated the damaging effects of chronic inflammation by inhibiting the downstream activation of NSPs. To support a range of preclinical programs and further understand how rodent species and strains may affect brensocatib's pharmacokinetic (PK) profile and its pharmacodynamic (PD) effects on NE, PR3, and CatG, an extensive naïve dosing study with brensocatib at different dosing levels, frequencies, and durations was undertaken. Dose-dependent PK exposure responses (AUC and Cmax) were observed regardless of the rodent species and strain. Overall, mice showed greater reduction in NSP activities compared to rats. Both mice and rats dosed once daily (QD) had equivalent NSP activity reduction compared to BID (twice a day) dosing when the QD dose was 1.5-times the BID daily dose. For both mouse strains, CatG activity was reduced the most, followed by NE, then PR3; whereas, for both rat strains, PR3 activity was reduced the most, followed by CatG, and then NE. Maximum reduction in NSP activities was observed after ∼7 days and recoveries were nearly symmetrical. These results may facilitate future in vivo brensocatib study dosing considerations, such as the timing of prophylactic or therapeutic administration, choice of species, dosage and dosing frequency.

Brensocatib, an oral, reversible inhibitor of dipeptidyl peptidase 1, mitigates interferon-α-accelerated lupus nephritis in mice.

Neutrophils have been implicated in initiating and perpetuating systemic lupus erythematosus and the resultant kidney damage in lupus nephritis (LN) patients, in part through an excessive release of neutrophil serine proteases (NSPs). NSP zymogens are activated by dipeptidyl peptidase 1 (DPP1) during neutrophil maturation and released by mature neutrophils in response to inflammatory stimuli. Thus, a potential strategy to attenuate disease progression in LN would be to inhibit DPP1. We tested whether brensocatib, a highly selective and reversible DPP1 inhibitor, could mitigate LN progression in an interferon-alpha (IFNα)-accelerated NZB/W F1 mouse model. To confirm brensocatib's pharmacodynamic effect on NSPs in this mouse strain, repeated dose studies were conducted for 7 and 14 days in naïve NZB/W F1 mice via oral gavage twice a day. Brensocatib at 2 and 20 mg/kg/day achieved a significant reduction in bone marrow NSP activities after 7 days of daily administration. To initiate LN disease progression, the mice were injected with an IFNα-expressing adenovirus. After 2 weeks, three brensocatib doses (or vehicle) were administered for 6 more weeks. Throughout the 8-week study, brensocatib treatment (20 mg/kg/day) significantly reduced the occurrence of severe proteinuria compared to the vehicle control. Brensocatib treatment also entailed a significant reduction in the urine albumin-to-creatinine ratio, indicating decreased kidney damage, as well as a significant reduction in blood urea nitrogen level, suggesting improved renal function. Based on kidney histopathology analysis, brensocatib treatment significantly lowered both the renal tubular protein score and the nephropathy score compared to the vehicle group. A trend towards reduced glomerulonephritis score with brensocatib treatment was also observed. Lastly, brensocatib significantly reduced LN mouse kidney infiltration by various inflammatory cells. In conclusion, these results suggest that brensocatib alters disease progression in LN mice and warrant further evaluation of DPP1 inhibition in LN.

Preservation solution Custodiol containing human alpha-1-antitrypsin improves graft recovery after prolonged cold ischemic storage in a rat model of heart transplantation.

The shortage of available donor hearts and the risk of ischemia/reperfusion injury restrict heart transplantation (HTX). Alpha-1-antitrypsin (AAT), a well-characterized inhibitor of neutrophil serine protease, is used in augmentation therapy to treat emphysema due to severe AAT deficiency. Evidence demonstrates its additional anti-inflammatory and tissue-protective effects. We hypothesized that adding human AAT in a preservation solution reduces graft dysfunction in a rat model of HTX following extended cold ischemic storage. The hearts from isogenic Lewis donor rats were explanted, stored for either 1h or 5h in cold Custodiol supplemented with either vehicle (1h ischemia, n=7 or 5h ischemia, n=7 groups) or 1 mg/ml AAT (1h ischemia+AAT, n=7 or 5h ischemia+AAT, n=9 groups) before heterotopic HTX. Left-ventricular (LV) graft function was evaluated in vivo 1.5h after HTX. Immunohistochemical detection of myeloperoxydase (MPO) was performed in myocardial tissue and expression of 88 gene quantified with PCR was analyzed both statistical and with machine-learning methods. After HTX, LV systolic function (dP/dtmax 1h ischemia+AAT 4197 ± 256 vs 1h ischemia 3123 ± 110; 5h ischemia+AAT 2858 ± 154 vs 5h ischemia 1843 ± 104mmHg/s, p<0.05) and diastolic function (dP/dtmin 5h ischemia+AAT 1516 ± 68 vs 5h ischemia 1095 ± 67mmHg/s, p<0.05) at an intraventricular volume of 90µl were improved in the AAT groups compared with the corresponding vehicle groups. In addition, the rate pressure product (1h ischemia+AAT 53 ± 4 vs 1h ischemia 26 ± 1; 5h ischemia+AAT 37 ± 3 vs 5h ischemia 21 ± 1mmHg*beats/min at an intraventricular volume of 90µl; p<0.05) was increased in the AAT groups compared with the corresponding vehicle groups. Moreover, the 5h ischemia+AAT hearts exhibited a significant reduction in MPO-positive cell infiltration in comparison to the 5h ischemia group. Our computational analysis shows that ischemia+AAT network displays higher homogeneity, more positive and fewer negative gene correlations than the ischemia+placebo network. We provided experimental evidence that AAT protects cardiac grafts from prolonged cold ischemia during HTX in rats.

Simultaneous inhibition of two neutrophil serine proteases by the S. aureus innate immune evasion protein EapH2

Extracellular adherence protein domain (EAP) proteins are high-affinity, selective inhibitors of neutrophil serine proteases (NSP), including cathepsin-G (CG) and neutrophil elastase (NE). Most Staphylococcus aureus isolates encode for two EAPs, EapH1 and EapH2, that contain a single functional domain and share 43% identity with one another. Although structure/function investigations from our group have shown that EapH1 uses a globally similar binding mode to inhibit CG and NE, NSP inhibition by EapH2 is incompletely understood due to a lack of NSP/EapH2 cocrystal structures. To address this limitation, we further studied NSP inhibition by EapH2 in comparison with EapH1. Like its effects on NE, we found that EapH2 is a reversible, time-dependent, and low nanomolar affinity inhibitor of CG. We characterized an EapH2 mutant which suggested that the CG binding mode of EapH2 is comparable to EapH1. To test this directly, we used NMR chemical shift perturbation to study EapH1 and EapH2 binding to CG and NE in solution. Although we found that overlapping regions of EapH1 and EapH2 were involved in CG binding, we found that altogether distinct regions of EapH1 and EapH2 experienced changes upon binding to NE. An important implication of this observation is that EapH2 might be capable of binding and inhibiting CG and NE simultaneously. We confirmed this unexpected feature by solving crystal structures of the CG/EapH2/NE complex and demonstrating their functional relevance through enzyme inhibition assays. Together, our work defines a new mechanism of simultaneous inhibition of two serine proteases by a single EAP protein.

Dipeptidyl peptidase-1 inhibition with brensocatib reduces the activity of all major neutrophil serine proteases in patients with bronchiectasis: results from the WILLOW trial

BackgroundBrensocatib is an oral, selective, reversible inhibitor of dipeptidyl peptidase-1 (DPP-1), responsible for activating neutrophil serine proteases (NSPs) including neutrophil elastase (NE), proteinase 3 (PR3), and cathepsin G (CatG). In chronic inflammatory lung diseases such as non-cystic fibrosis bronchiectasis (NCFBE), neutrophils accumulate in the airways resulting in excess active NSPs that cause damaging inflammation and lung destruction.MethodsThe 24-week WILLOW trial (NCT03218917) was a randomized, double-blind, placebo-controlled, parallel-group trial in patients with NCFBE conducted at 116 sites across 14 countries. In this trial, treatment with brensocatib was associated with improvements in clinical outcomes including time to first exacerbation, reduction in exacerbation frequency and a reduction in NE activity in sputum. An exploratory analysis of NE activity in white blood cell (WBC) extracts and NE, PR3 and CatG activity in sputum was conducted to further characterize brensocatib’s effect and identify potential correlated effects.ResultsNE, PR3 and CatG activities were reduced in sputum and NE activity was reduced in WBC extracts in a dose-dependent manner after four weeks of brensocatib treatment, with a return to baseline four weeks after the end of treatment. Brensocatib produced the greatest reduction in the sputum activity of CatG, followed by NE and then PR3. Positive correlations among the sputum NSPs were observed both at baseline and in response to treatment, with the strongest correlation among the sputum NSPs for NE and CatG.ConclusionsThese results suggest a broad anti-inflammatory effect of brensocatib underlying its clinical efficacy observed in NCFBE patients.Trial registration: The study was approved by the corresponding ethical review boards of all participating centers. The trial was approved by the Food and Drug Administration and registered at clinicaltrials.gov (NCT03218917) on July 17, 2017 and approved by the European Medicines Agency and registered at the European Union Clinical trials Register (EudraCT No. 2017-002533-32). An independent, external data and safety monitoring committee (comprising physicians with pulmonary expertise, a statistician experienced in the evaluation of clinical safety, and experts in periodontal disease and dermatology) reviewed all adverse events.

Complete non-proline backbone resonance assignments of the S. aureus neutrophil serine protease inhibitor, EapH1.

The S. aureus extracellular adherence protein (Eap) and its homologs, EapH1 and EapH2, serve roles in evasion of the human innate immune system. EapH1 binds with high-affinity and inhibits the neutrophil azurophilic granule proteases neutrophil elastase, cathepsin-G and proteinase-3. Previous structural studies using X-ray crystallography have shown that EapH1 binds to neutrophil elastase and cathepsin-G using a globally similar binding mode. However, whether the same holds true in solution is unknown and whether the inhibitor experiences dynamic changes following binding remains uncertain. To facilitate solution-phase structural and biochemical studies of EapH1 and its complexes with neutrophil granule proteases, we have characterized EapH1 by multidimensional NMR spectroscopy. Here we report a total of 100% of the non-proline backbone resonance assignments of EapH1 with BMRB accession number 50,304.

The intratumour microbiota and neutrophilic inflammation in squamous cell vulvar carcinoma microenvironment

BackgroundA causal link between microbiota composition (dysbiosis) and oncogenesis has been demonstrated for several types of cancer. Neutrophils play a role in both immune protection against bacterial threats and carcinogenesis. This study aimed to characterise intratumoral bacteria in vulvar squamous cell carcinoma (VSCC) and their putative effect on neutrophil recruitment and cancer progression.MethodsClinical material was obtained from 89 patients with VSCC. Next-generation sequencing (NGS) of 16S rRNA and quantitative polymerase chain reaction (qPCR) were used to detect bacterial species in VSCC. To verify neutrophil activation, CD66b expression in tumour specimens was analysed by immunohistochemistry (IHC). Subsequently, IHC was applied to detect the main neutrophil serine proteases (NSPs), cathepsin G (CTSG), neutrophil elastase (ELANE), and proteinase 3 (PRTN3) in VSCC.ResultsFusobacterium nucleatum and Pseudomonas aeruginosa were identified as tumour-promoting bacteria, and their presence was found to be associated with a shorter time to progression in VSCC patients. Furthermore, high abundance of CD66b, the neutrophil activation marker, in VSCC samples, was found to relate to poor survival of patients with VSCC. The selected NSPs were shown to be expressed in vulvar tumours, also within microabscess. The increased numbers of microabscesess were correlated with poor survival in VSCC patients.ConclusionsOur results show that neutrophilic inflammation seem to be permissive for tumour-promoting bacteria growth in VSCC. The findings provide new therapeutic opportunities, such as based on shifting the balance of neutrophil populations to those with antitumorigenic activity and on targeting NSPs produced by activated neutrophils at the inflammation sites.

Homogeneous, Synthetic, Non-Saccharide Glycosaminoglycan Mimetics as Potent Inhibitors of Human Cathepsin G.

Cathepsin G (CatG) is a pro-inflammatory neutrophil serine protease that is important for host defense, and has been implicated in several inflammatory disorders. Hence, inhibition of CatG holds much therapeutic potential; however, only a few inhibitors have been identified to date, and none have reached clinical trials. Of these, heparin is a well-known inhibitor of CatG, but its heterogeneity and bleeding risk reduce its clinical potential. We reasoned that synthetic small mimetics of heparin, labeled as non-saccharide glycosaminoglycan mimetics (NSGMs), would exhibit potent CatG inhibition while being devoid of bleeding risks associated with heparin. Hence, we screened a focused library of 30 NSGMs for CatG inhibition using a chromogenic substrate hydrolysis assay and identified nano- to micro-molar inhibitors with varying levels of efficacy. Of these, a structurally-defined, octasulfated di-quercetin NSGM 25 inhibited CatG with a potency of ~50 nM. NSGM 25 binds to CatG in an allosteric site through an approximately equal contribution of ionic and nonionic forces. Octasulfated 25 exhibits no impact on human plasma clotting, suggesting minimal bleeding risk. Considering that octasulfated 25 also potently inhibits two other pro-inflammatory proteases, human neutrophil elastase and human plasmin, the current results imply the possibility of a multi-pronged anti-inflammatory approach in which these proteases are likely to simultaneously likely combat important conditions, e.g., rheumatoid arthritis, emphysema, or cystic fibrosis, with minimal bleeding risk.

Abstract 2995: Cross-presented serine proteases as immunotherapy targets for lung cancer and osteosarcoma

Abstract Background: Immunotherapy is the standard of care for many solid tumor malignancies. However, due to a paucity of known tumor antigens in non-small cell lung cancer (NSCLC) and osteosarcoma (OS), identification of novel immunogenic antigens is needed. Our group has experience with neutrophil serine proteases (NSP) derived from the azurophilic granules of polymorphonuclear leukocytes (PMN), specifically, cathepsin (CG), proteinase 3 (P3), and neutrophil elastase (NE). We have identified two HLA-A2 (HLA-A*0201)-restricted nonameric peptides: CG1 (FLLPTGAEA), derived from CG, and PR1 (VLQELNVTV), derived from NE and P3. We have previously shown that CG1 and PR1 are effective targets in hematological malignancies and that PR1 can be a target for some solid tumor malignancies. Here, we extend our findings to demonstrate that CG1 and PR1 can be immunotherapeutic targets for NSCLC and OS. Methods: Healthy donor PMN were isolated from buffy coats using double Ficoll gradient centrifugation. To evaluate uptake, malignant cells were pulsed with PMN lysates, harvested, permeabilized, and stained with anti-CG, anti-NE or anti-P3. To evaluate cross-presentation, cells were cultured with PMN lysates, harvested and stained with CG1 TCR-like antibody, or PR1 TCR-like antibody (8F4). Flow cytometry was performed using the Fortessa X-20 Cell Analyzer. CG1- or PR1-specific cytotoxic T-lymphocyte (CTL) were expanded from healthy donor peripheral blood mononuclear cells. Standard cytotoxicity assays were used to evaluate the lysis of target cells co-cultured with CG1- or PR1-specific CTL. Results: We have previously demonstrated that NE and P3 are taken up and cross-presented by NSCLC and become targets for PR1-CTL, thus in this study, we investigate if NSCLC cells take up CG, and whether OS cells take up NE and P3, resulting in enhanced cytotoxicity by peptide-specific CTLs. We first employed The Cancer Cell Line Encyclopedia to show the absence of NSP’s in NSCLC and OS cell lines. RT-PCR confirmed lack of endogenous CG mRNA expression in NSCLC and OS, and lack of NE and P3 in OS cell lines. Next, we analyzed antigen cross-presentation and showed that NSCLC cells take up and cross-present CG, leading a 13.3-fold increase in CG1-CTL killing of NSCLC cells pulsed with CG versus non-pulsed cells. In addition, OS cells take up and cross-present NE and P3, with a 13.1-fold increase in PR1-CTL killing of OS cells that were pulsed with NE and P3 vs. non-pulsed cells. Conclusion: Our data define two novel HLA-A2 restricted peptides that can be targeted in NSCLC and OS. Specifically, CG1 and PR1 are presented on the surfaces of NSCLC and OS, increasing their susceptibility to killing by CG1 and PR1 specific CTL. Our work represents a novel link between innate and adaptive immune responses in solid tumors and identifies potential antigen targets for CTL, peptide vaccines, and TCR-like antibodies in the setting of NSCLC and OS. Citation Format: Amber Gibson, Pariya Sukhumalchandra, Celine Kerros, Na Qiao, Anne Philips, Mao Zhang, Sami Alkoutami, Scott Semelsberger, Yoshimi Lu, Lauren Byers, Ze Tian, Chunhua Shi, Jun Yan, Dongxing Zha, Alejandro Marinos, Anne Sergeeva, Hong He, Lisa St. John, Jeffrey J. Molldrem, Gheath Alatrash. Cross-presented serine proteases as immunotherapy targets for lung cancer and osteosarcoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 2995.

Benefit-risk assessment of brensocatib for treatment of non-cystic fibrosis bronchiectasis.

Brensocatib is a novel anti-inflammatory therapy in development for bronchiectasis treatment. Phase 2 WILLOW trial data demonstrate a low number needed to treat and negative number needed to harm, suggesting a favourable benefit-risk profile. https://bit.ly/3SbisW3.

Association of admission neutrophil serine proteinases levels with the outcomes of acute ischemic stroke: a prospective cohort study

BackgroundNeutrophil serine proteinases (NSPs), released by activated neutrophils, are key proteins involved in the pathophysiologic processes of stroke. NSPs are also implicated in the process and response of thrombolysis. This study aimed to analyze three NSPs (neutrophil elastase, cathepsin G, and proteinase 3) in relation to acute ischemic stroke (AIS) outcomes and in relation to the outcomes of patients treated with intravenous recombinant tissue plasminogen activator (IV-rtPA).MethodsAmong 736 patients prospectively recruited at the stroke center from 2018 to 2019, 342 patients diagnosed with confirmed AIS were included. Plasma neutrophil elastase (NE), cathepsin G (CTSG), and proteinase 3 (PR3) concentrations were measured on admission. The primary endpoint was unfavorable outcome defined as modified Rankin Scale score 3–6 at 3 months, and the secondary endpoints were symptomatic intracerebral hemorrhage (sICH) within 48 h, and mortality within 3 months. In the subgroup of patients who received IV-rtPA, post-thrombolysis early neurological improvement (ENI) (defined as National Institutes of Health Stroke Scale score = 0 or decrease of ≥ 4 within 24 h after thrombolysis) was also included as the secondary endpoint. Univariate and multivariate logistic regression analyses were performed to evaluate the association between NSPs levels and AIS outcomes.ResultsHigher NE and PR3 plasma levels were associated with the 3-month mortality and 3-month unfavorable outcome. Higher NE plasma levels were also associated with the risk of sICH after AIS. After adjusting for potential confounders, plasma NE level > 229.56 ng/mL (odds ratio [OR] = 4.478 [2.344–8.554]) and PR3 > 388.77 ng/mL (OR = 2.805 [1.504–5.231]) independently predicted the 3-month unfavorable outcome. Regarding rtPA treatment, patients with NE plasma concentration > 177.22 ng/mL (OR = 8.931 [2.330–34.238]) or PR3 > 388.77 ng/mL (OR = 4.275 [1.045–17.491]) were over 4 times more likely to suffer unfavorable outcomes after rtPA treatment. The addition of NE and PR3 to clinical predictors of unfavorable functional outcome after AIS and the outcome after rtPA treatment improved discrimination as well as reclassification (integrated discrimination improvement = 8.2% and 18.1%, continuous net reclassification improvement = 100.0% and 91.8%, respectively).ConclusionsPlasma NE and PR3 are novel and independent predictors of 3-month functional outcomes after AIS. Plasma NE and PR3 also possess predictive value to identify patients with unfavorable outcomes after rtPA treatment. NE is probably an important mediator of the effects of neutrophils on stroke outcomes, which worth further investigation.

Characterization of two distinct neutrophil serine protease–binding modes within a Staphylococcus aureus innate immune evasion protein family

Extracellular adherence domain proteins (EAPs) are a class of innate immune evasion proteins secreted by the human pathogen Staphylococcus aureus. EAPs are potent and selective inhibitors of cathepsin-G (CG) and neutrophil elastase (NE), which are the two most abundant neutrophil serine proteases (NSPs). Previous work from our group has shown that the prototypical EAP, EapH1, relies on plasticity within a single inhibitory site to block the activities of CG and NE. However, whether other EAPs follow similar structure/function relationships is unclear. To address this question, we studied the inhibitory properties of the first (Eap1) and second (Eap2) domains of the modular Extracellular Adherence Protein of Staphylococcus aureus and determined their structures when bound to CG and NE, respectively. We observed that both Eap1 and Eap2 displayed time-dependent inhibition of CG (on the order of 10-9 M) and of NE (on the order of 10-10 M). We also found that whereas the structures of Eap1 and Eap2 bound to CG showed an overall inhibitory mode like that seen previously for EapH1, the structures of Eap1 and Eap2 bound to NE revealed a new inhibitory mode involving a distal region of the EAP domain. Using site-directed mutagenesis of Eap1 and Eap2, along with enzyme assays, we confirmed the roles of interfacial residues in NSP inhibition. Taken together, our work demonstrates that EAPs can form structurally divergent complexes with two closely related serine proteases, and further suggests that certain EAPs may be capable of inhibiting two NSPs simultaneously.

Neutrophil serine proteases

The identification and characterization of the four active neutrophil serine proteases (NSPs) have provided a better understanding of their roles in various physiological and pathological processes. The availability of appropriate tools such as substrates, inhibitors, and activity-based probes (ABPs) for studying their activity and functions in cells has become increasingly important. In this paper, the authors provide a comprehensive overview of the current state of knowledge on the tools available for studying NSPs. The substrates, inhibitors, and ABPs that have been developed to date are described, including their strengths and limitations. The authors also discuss the potential implications of these tools for future research on NSPs, including their potential use in the development of new therapeutics for various diseases. Overall, this paper highlights the importance of understanding the activity and functions of NSPs and provides valuable information on the tools available for studying these proteases.

Pathogenesis of autoimmune and hereditary pancreatitis with a focus on neutrophil granulocytes and neutrophil serine proteases

Hereditary and autoimmune pancreatitis are two rare forms of inflammatory pancreatic disorders. Both share similarities with acute, acute recurrent, and chronic pancreatitis. Regarding their pathogenesis, the premature activation of the digestive protease trypsinogen and the infiltration of inflammatory cells such as polymorphonuclear leukocytes and macrophages into the pancreas are highly relevant and can reciprocally amplify inflammation. Neutrophil serine proteases are the main components of neutrophil granulocytes and have different pro-inflammatory effects in many diseases. However, their role in pancreatitis is still limited. This section focuses on known findings regarding the role of this group of enzymes in hereditary and autoimmune pancreatitis.

Immune cell-derived serine protease as pathogenic drivers of vascular remodeling in pulmonary arterial hypertension

In recent years, accumulating evidence has shown that pulmonary arterial hypertension (PAH) has a strong underlying inflammatory component. Vascular remodeling, a common pathology observed in all forms of pulmonary hypertension (PH), is accompanied by a pronounced accumulation of leukocytes around and within the vessels. Proteolytic products of immune cells, particularly neutrophil and mast cell serine proteases, have been shown to play a central pathogenic role in vascular remodeling and PAH development. Serine proteases are involved in many aspects of the inflammatory response, such as extracellular matrix degradation, regulation of bioavailability of cytokines, chemokines, and growth factors, and dysregulation of their activity can have devastating consequences. In this review, we will focus on immune dysregulation in PAH and shed light on the pro-inflammatory role of serine proteases in vascular pathology observed in the context of this disease.

Abstract 1333: A Structural Basis for Bifunctional and Simultaneous Inhibition of Neutrophil Serine Proteases by Members of a Staphylococcal Innate Immune Evasion Protein Family

Abstract 1333: A Structural Basis for Bifunctional and Simultaneous Inhibition of Neutrophil Serine Proteases by Members of a Staphylococcal Innate Immune Evasion Protein Family