Novel Sulfonamide Analogs of Sivelestat as Potent Human Neutrophil Elastase Inhibitors

Efficacy of sivelestat in alleviating postoperative pulmonary injury in patients with acute aortic dissection undergoing total arch replacement: a retrospective cohort study

OBJECTIVE

Sivelestat may reduce postoperative pulmonary injury after total arch replacement (TAR). This study aimed to evaluate whether the preoperative PaO2/FiO2 (P/F) ratio affects the efficacy of sivelestat in reducing postoperative pulmonary injury in patients with acute aortic dissection (AAD) who underwent TAR using deep hypothermic circulatory arrest (DHCA).

METHODS

Data of patients with AAD who underwent TAR using DHCA in a tertiary hospital between February 1, 2022, and December 30, 2022, were retrospectively reviewed. The patients were divided into the sivelestat and control groups. Three subgroup analyses were performed based on the postoperative P/F ratio. The primary clinical outcomes were assessed to determine the efficacy and safety of sivelestat in managing postoperative pulmonary dysfunction in patients undergoing cardiopulmonary bypass.

RESULTS

A total of 187 patients were included, with 95 in the sivelestat group and 92 in the control group. No significant differences were found in the clinical variables between the two groups (all P > 0.05), except for some improvements in the inflammatory biomarker levels (including white blood cell count, neutrophil count, and C-reactive protein). Subgroup analysis revealed that sivelestat treatment significantly increased the P/F ratio on the 4th day and 3rd day after TAR in patients with mild lung injury (P = 0.02) and moderate lung injury (P = 0.03), respectively. Additionally, sivelestat reduced the levels of several postoperative inflammatory biomarkers in both subgroups.

CONCLUSIONS

Among patients with AAD with mild or moderate preoperative lung injury, defined by a low P/F ratio, sivelestat significantly improved the postoperative P/F ratio and attenuated inflammatory responses after TAR. These findings suggest an important avenue for further research.

Sensitive quantification of fibroblast activation protein and high-throughput screening for inhibition by FDA-approved compounds

Fibroblast activation protein (FAP) has been extensively studied as a cancer biomarker for decades. Recently, small-molecule FAP inhibitors have been widely adopted as a targeting moiety of experimental theranostic radiotracers. Here we present a fast qPCR-based analytical method allowing FAP inhibition screening in a high-throughput regime. To identify clinically relevant compounds that might interfere with FAP-targeted approaches, we focused on a library of FDA-approved drugs. Using the DNA-linked Inhibitor Antibody Assay (DIANA), we tested a library of 2667 compounds within just a few hours and identified numerous FDA-approved drugs as novel FAP inhibitors. Among these, prodrugs of cephalosporin antibiotics and reverse transcriptase inhibitors, along with one elastase inhibitor, were the most potent FAP inhibitors in our dataset. In addition, by employing FAP DIANA in the quantification mode, we were able to determine FAP concentrations in human plasma samples. Together, our work expands the repertoire of FAP inhibitors, analyzes the potential interference of co-administered drugs with FAP-targeting strategies, and presents a sensitive and low-consumption ELISA alternative for FAP quantification with a detection limit of 50 pg/ml.

Curcumol derivatives exhibit ameliorating effects on lipopolysaccharide-induced acute lung injury: Synthesis, biological evaluation, structure-activity relationship and action mechanism

Acute lung injury (ALI) is an intricate clinical disease marked by high mortality and a sudden start. Currently, although there are no specific therapeutics for ALI, the administration of anti-inflammatory drugs is a promising treatment strategy. Curcumol, a terpenoid natural product, has demonstrated significant anti-inflammatory activity. Herein, we designed and synthesised 42 curcumol derivatives using curcumol as the core scaffold. These derivatives underwent in vitro screening for anti-inflammatory activity, and their structure-activity relationship was assessed. Among them, derivative 2 exhibited potent anti-inflammatory potential, inhibiting the expression of inflammatory markers at the nanomolar level. In addition, its water solubility was considerably improved, thereby laying the foundation for enhanced druggability. Derivative 2 also ameliorated lipopolysaccharide (LPS)-induced ALI and reduced pulmonary inflammation at a dose of 5 mg/kg. Proteomics analysis revealed that the anti-inflammatory effect of this compound primarily involved the mTOR signalling pathway. Furthermore, molecular docking and cellular thermal shift assays indicated that GSK3β is a critical target of action of derivative 2, as verified via western blotting. These findings suggest that derivative 2 can be a lead therapeutic compound for ALI, with GSK3β emerging as a promising novel target for the development of specific anti-ALI drugs.

Robustaflavone as a novel scaffold for inhibitors of native and auto-proteolysed human neutrophil elastase

Human neutrophil elastase (HNE) plays a key role in initiating inflammation in the cardiopulmonary and systemic contexts. Pathological auto-proteolysed two-chain (tc) HNE exhibits reduced binding affinity with inhibitors. Using AutoDock Vina v1.2.0, 66 flavonoid inhibitors, sivelestat and alvelestat were docked with single-chain (sc) HNE and tcHNE. Schrodinger PHASE v13.4.132 was used to generate a 3D-QSAR model. Molecular dynamics (MD) simulations were conducted with AMBER v18. The 3D-QSAR model for flavonoids with scHNE showed r2 = 0.95 and q2 = 0.91. High-activity compounds had hydrophobic A/A2 and C/C2 rings in the S1 subsite, with hydrogen bond donors at C5 and C7 positions of the A/A2 ring, and the C4' position of the B/B1 ring. All flavonoids except robustaflavone occupied the S1'-S2' subsites of tcHNE with decreased AutoDock binding affinities. During MD simulations, robustaflavone remained highly stable with both HNE forms. Principal Component Analysis suggested that robustaflavone binding induced structural stability in both HNE forms. Cluster analysis and free energy landscape plots showed that robustaflavone remained within the sc and tcHNE binding site throughout the 100 ns MD simulation. The robustaflavone scaffold likely inhibits both tcHNE and scHNE. It is potentially superior to sivelestat and alvelestat and can aid in developing therapeutics targeting both forms of HNE.

The Multifaceted Role of Neutrophils in NSCLC in the Era of Immune Checkpoint Inhibitors

Lung cancer is the most common cause of cancer-related death in both males and females in the U.S. and non-small-cell lung cancer (NSCLC) accounts for 85%. Although the use of first- or second-line immune checkpoint inhibitors (ICIs) exhibits remarkable clinical benefits, resistance to ICIs develops over time and dampens the efficacy of ICIs in patients. Tumor-associated neutrophils (TANs) have an important role in modulating the tumor microenvironment (TME) and tumor immune response. The major challenge in the field is to characterize the TANs in NSCLC TME and understand the link between TAN-related immunosuppression with ICI treatment response. In this review, we summarize the current studies of neutrophil interaction with malignant cells, T-cells, and other components in the TME. Ongoing clinical trials are aimed at utilizing reagents that have putative effects on tumor-associated neutrophils, in combination with ICI. Elevated neutrophil populations and neutrophil-associated factors could be potential therapeutic targets to enhance anti-PD1 treatment in NSCLC.

Ebselen analogues with dual human neutrophil elastase (HNE) inhibitory and antiradical activity

Human neutrophil elastase (HNE) plays an essential role in host defense against bacteria but is also involved in several respiratory diseases. Recent reports suggest that compounds exhibiting a combination of HNE inhibitory activity with antiradical properties may be therapeutically beneficial for the treatment of respiratory diseases involving inflammation and oxidative stress. We report here the synthesis and biological evaluation of novel ebselen analogues exhibiting HNE inhibitory and antiradical activities. HNE inhibition was evaluated in an enzymatic system using human HNE, whereas antiradical activity was evaluated in a cell-based assay system using phorbol 12-myristate 13-acetate (PMA)-stimulated murine bone marrow leukocytes as the source of reactive oxygen species (ROS). HNE inhibition was due to the N-CO group targeting Ser195-OH at position 2 of the scaffold, while antiradical activity was due to the presence of the selenium atom. The most active compounds 4d, 4f, and 4j exhibited a good balance between anti-HNE (IC50 = 0.9-1.4 μM) and antiradical activity (IC50 = 0.05-0.7 μM). Additionally, the solid-state structure of 4d was determined and compared to that of the similar compound N-propionyl-1,2-benzisoselenazol-3(2H)-one.

Safety, tolerability, pharmacokinetics and neutrophil elastase inhibitory effects of Sivelestat: A randomized, double-blind, placebo-controlled single- and multiple-dose escalation study in Chinese healthy subjects

BACKGROUND AND OBJECTIVE

Neutrophil elastase has been identified as a potential therapeutic target for acute lung injury or acute respiratory distress syndrome, and Sivelestat is a selective, reversible and competitive neutrophil elastase inhibitor. This study was designed to investigate the safety, tolerability, pharmacokinetics and neutrophil elastase inhibitory effects of Sivelestat in healthy Chinese subjects.

METHODS

A randomized, double-blind, placebo-controlled single- and multiple-dose escalation clinical trial was carried out. Briefly, healthy volunteers in twelve cohorts with 8 per cohort received 1.0-20.2 mg/kg/h Sivelestat or placebo in an intravenous infusion manner for two hours, and healthy volunteers in four cohorts received two hours intravenous infusion of 2.0-5.0 mg/kg/h Sivelestat or placebo with an interval of twelve hours for seven times. The safety and tolerability were evaluated and serial blood samples were collected for pharmacokinetics and neutrophil elastase inhibitory effects analysis at the specified time-point.

RESULTS

A total of 128 subjects were enrolled and all participants completed the study except one. Sivelestat exhibited satisfactory safety and tolerability up to 20.2 mg/kg/h in single-dose cohorts and 5.0 mg/kg/h in multiple-dose cohorts. Even so, more attention should be paid to the safety risks when using high doses. The Cmax and AUC of Sivelestat increased in a dose dependent manner, and Tmax was similar for different dose cohorts. In multiple-dose cohorts, the plasma concentrations reached steady state 48 h after first administration and the accumulation of Cmax and AUC was not obvious. Furthermore, the Cmin_ss of 5.0 mg/kg/h dose cohort could meet the needs of clinical treatment. For some reason, the pharmacodynamics data revealed that the inhibitory effect of Sivelestat on neutrophil elastase content in healthy subjects was inconclusive.

CONCLUSION

Sivelestat was safe and well tolerated with appropriate pharmacokinetic parameters, which provided support for more diverse dosing regimen in clinical application.

CLINICAL TRIAL REGISTRATION

www.chinadrugtrials.org.cn identifier is CTR20210072.

Human neutrophil elastase inhibitors: Classification, biological-synthetic sources and their relevance in related diseases

BACKGROUND

Human neutrophil elastase is a multifunctional protease enzyme whose function is to break the bonds of proteins and degrade them to polypeptides or amino acids. In addition, it plays an essential role in the immune mechanism against bacterial infections and represents a key mediator in tissue remodeling and inflammation. However, when the extracellular release of this enzyme is dysregulated in response to low levels of its physiological inhibitors, it ultimately leads to the degradation of proteins, in particular elastin, as well as other components of the extracellular matrix, producing injury to epithelial cells, which can promote sustained inflammation and affect the innate immune system, and, therefore, be the basis for the development of severe inflammatory diseases, especially those associated with the cardiopulmonary system.

OBJECTIVE

This review aims to provide an update on the elastase inhibitory properties of several molecules, either synthetic or biological sources, as well as their classification and relevance in related pathologies since a clear understanding of the function of these molecules with the inhibitory capacity of this protease can provide valuable information for the development of pharmacological therapies that manage to modify the prognosis and survival of various inflammatory diseases.

METHODS

Collected data from scientific databases, including PubMed, Google Scholar, Science Direct, Nature, Wiley, Scopus, and Scielo. Articles published in any country and language were included.

RESULTS

We reviewed and included 132 articles conceptualizing neutrophil elastase activity and known inhibitors.

CONCLUSION

Understanding the mechanism of action of elastase inhibitors based on particular aspects such as their kinetic behavior, structure-function relationship, chemical properties, origin, pharmacodynamics, and experimental progress has allowed for a broad classification of HNE inhibitors.

Enzyme targeted delivery of sivelestat loaded nanomicelle inhibits arthritic severity in experimental arthritis

AIMS

Rheumatoid arthritis (RA) is chronic inflammatory disorder mainly affects the lining of articular cartilage of synovial joints characterized by severe inflammation and joint damage. The expression of proteolytic enzymes like MMP-2 and Neutrophil Elastase (NE) worsens the RA condition. To address this concern, we have synthesized dual enzyme targeted chlorotoxin conjugated nanomicelles loaded with sivelestat as broad spectrum treatment for RA.

MATERIALS AND METHODS

Conjugation of the chlorotoxin over nanomicelle and incorporation of sivelestat in nanomicelle provide it dual targeting potential. The sivelestat loaded nanomicelle (SLM) evaluated for the drug release and in-vitro cytocompatibility. Further, investigated its in-vivo anti-arthritic potential on collagen-induced arthritis in wistar rats.

KEY FINDINGS

The microscopic observation of SLM showed spherical ball like appearance with size ranging from 190 to 230 nm. SLM showed good drug loading and encapsulation efficiency along with no cytotoxicity against healthy cell lines. In-vivo therapeutic assessment on collagen induced arthritis rat model showed potential chondroprotection. The microscopic visualization of articular cartilage by staining showed that it restores the cartilage integrity and lowers the expression of pro-inflammatory enzymes showed by Immunohistochemistry and Immunofluorescence. We observed that, it restrain the mediators of synovial inflammation by simultaneous inhibition of the proteolytic enzymes involved in swelling, cartilage destruction and joint damage which provides strong chondroprotection.

SIGNIFICANCE

We report that significant alleviation of inflammation and inhibition of proteolytic enzymes together might provide enhanced potential for the treatment and management of RA.

Thalidomide derivatives as nanomolar human neutrophil elastase inhibitors: Rational design, synthesis, antiproliferative activity and mechanism of action

Here, we rationally designed a human neutrophil elastase (HNE) inhibitors 4a-4f derived from thalidomide. The HNE inhibition assay showed that synthesized compounds 4a, 4b, 4e and 4f demonstrated strong HNE inhibiton properties with IC50 values of 21.78-42.30 nM. Compounds 4a, 4c, 4d and 4f showed a competitive mode of action. The most potent compound 4f shows almost the same HNE inhibition as sivelestat. The molecular docking analysis revealed that the strongest interactions occur between the azetidine-2,4-dione group and the following three aminoacids: Ser195, Arg217 and His57. A high correlation between the binding energies and the experimentally determined IC50 values was also demonstrated. The study of antiproliferative activity against human T47D (breast carcinoma), RPMI 8226 (multiple myeloma), and A549 (non-small-cell lung carcinoma) revealed that designed compounds were more active compared to thalidomide, pomalidomide and lenalidomide used as the standard drugs. Additionally, the most active compound 4f derived from lenalidomide induces cell cycle arrest at the G2/M phase and apoptosis in T47D cells.

Discovery of New 3,3-Diethylazetidine-2,4-dione Based Thiazoles as Nanomolar Human Neutrophil Elastase Inhibitors with Broad-Spectrum Antiproliferative Activity

A series of 3,3-diethylazetidine-2,4-dione based thiazoles 3a–3j were designed and synthesized as new human neutrophil elastase (HNE) inhibitors in nanomolar range. The representative compounds 3c, 3e, and 3h exhibit high HNE inhibitory activity with IC₅₀ values of 35.02–44.59 nM, with mixed mechanism of action. Additionally, the most active compounds 3c and 3e demonstrate high stability under physiological conditions. The molecular docking study showed good correlation of the binding energies with the IC₅₀ values, suggesting that the inhibition properties are largely dependent on the stage of ligand alignment in the binding cavity. The inhibition properties are correlated with the energy level of substrates of the reaction of ligand with Ser195. Moreover, most compounds showed high and broad-spectrum antiproliferative activity against human leukemia (MV4-11), human lung carcinoma (A549), human breast adenocarcinoma (MDA-MB-231), and urinary bladder carcinoma (UMUC-3), with IC₅₀ values of 4.59–9.86 μM. Additionally, compounds 3c and 3e can induce cell cycle arrest at the G2/M phase and apoptosis via caspase-3 activation, leading to inhibition of A549 cell proliferation. These findings suggest that these new types of drugs could be used to treat cancer and other diseases in which immunoreactive HNE is produced.

1,5,6,7-Tetrahydro-4H-indazol-4-ones as human neutrophil elastase (HNE) inhibitors

Human neutrophil elastase (HNE) is a serine protease that is expressed in polymorphonuclear neutrophils. It has been recognized as an important therapeutic target for treating inflammatory diseases, especially related to the respiratory system, but also for various types of cancer. Thus, compounds able to inhibit HNE are of great interest in medicinal chemistry. In the present paper, we report the synthesis and biological evaluation of a new series of HNE inhibitors with an innovative 1,5,6,7-tetrahydro-4H-indazol-4-one core that was developed as a molecular modification of our previously reported indazole-based HNE inhibitors. Since the 1,5,6,7-tetrahydro-4H-indazol-4-one scaffold can occur in two possible tautomeric forms, the acylation/alkylation reactions resulted in a mixture of the two isomers, often widely unbalanced in favor of one form. Using analytical techniques and NMR spectroscopy, we characterized and separated the isomer pairs and confirmed the compounds used in biological testing. Analysis of the compounds for HNE inhibitory activity showed that they were potent inhibitors, with K_i values in the low nanomolar range (6-35 nM). They also had reasonable stability in aqueous buffer, with half-lives over 1 h. Overall, our results indicate that the 1,5,6,7-tetrahydro-4H-indazol-4-one core is suitable for the synthesis of potent HNE inhibitors that could be useful in the development of new therapeutics for treating diseases involving excessive HNE activity.