Protease inhibitors elicit anti-inflammatory effects in CF mice with Pseudomonas aeruginosa acute lung infection

Green Biosynthesis of Bimetallic Copper Oxide-Selenium Nanoparticles Using Leaf Extract of Lagenaria Siceraria: Antibacterial, Anti-Virulence Activities Against Multidrug-Resistant Pseudomonas Aeruginosa

Introduction

Clinical isolates of Pseudomonas aeruginosa (P. aeruginosa) are among the most recovered bacteria with phenotypic antimicrobial resistance. Bimetallic nanoparticles (BNPs) have received much attention for antimicrobial activity in the last decade. This research aimed to biosynthesize bimetallic copper oxide-selenium nanoparticles (CuO-Se BNPs) and to assess its bioactivity on various P. aeruginosa clinical isolates.

Methodology

Based on the possible synergistic effects, CuO-Se BNPs were selected and biosynthesized using leaf extract of Lagenaria siceraria (L. siceraria) for the first time. The obtained BNPs were characterized using UV-vis spectroscopy, X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDX), and transmission and scanning electron microscopes. The capability of Cu-Se BNPs to cease the growth of P. aeruginosa isolates and to reduce their virulence characters was evaluated. Also, different cell lines were used to assess its cytotoxicity and anticancer activity.

Results

The elemental composition of CuO and Se was revealed by the UV, XRD, and EDX data, indicating the synthesis of CuO-Se core shell BNPs with a size of 50 nm. In well diffusion assay, CuO-Se BNPs P. aeruginosa growth with 10-21 mm inhibition zone diameter and 38-95% inhibition. Also, the minimum inhibitory concentration and minimum bactericidal concentration were in a relatively wide range of 7.8-250 μg/mL and 31.2-500 μg/mL, respectively, with tolerance level range of 2-16. Additionally, CuO-Se BNPs shown anti-pyocyanin activity of 4.35-63.21% inhibition while the anti-proteolytic activity was in a range of 4.96-12.59% and anti-pyoverdine effect was in a range of 0.24-83.41%. The IC50 against Wi-38 normal cells was 267.2 µg/mL while the IC50 were 31.1 and 83.4 µg/mL against MCF-7 and Hep-G2, respectively, indicating promising anticancer activity.

Conclusion

This research demonstrates the promising antibacterial, anti-virulence, and antitumor properties with safe low concentrations of CuO-Se NPs, synthesized via an eco-friendly green synthesis method without the use of toxic chemicals, offering a sustainable and cost-effective alternative.

Synergistic therapeutic effect of parecoxib and ilomastat combination in osteoarthritis via inhibition of IL-17/PI3K/AKT/NF-κB activity

BACKGROUND

Osteoarthritis is a degenerative disease, and current drug treatment is to give nonsteroidal anti-inflammatory drugs to relieve symptoms. The anti-inflammatory ability of parecoxib and ilomastat has been confirmed, but the synergistic effect of combined administration in osteoarthritis has not been clear.

METHODS

Mouse primary chondrocytes stimulated with IL-1β were cultured. The expression levels of inflammatory cytokines and matrix metalloproteinases were investigated by western blotting, quantitative real-time polymerase chain reaction and ELISA. The effects of parecoxib and ilomastat on chondrocyte apoptosis were evaluated by flow cytometry. In addition, the rat model of osteoarthritis was established by meniscal instability, and the morphological changes of cartilage and the expression levels of related molecules were monitored using Safranin O-Fast green and immunohistochemical staining after intra-articular injection of parecoxib, ilomastat, and the combination of the two.

RESULTS

In vitro experiments showed that the combined administration of parecoxib and ilomastat more effectively inhibited the expression of proinflammatory factors and matrix metalloproteinases compared with single drug administration. The combined drug treatment could more effectively inhibit IL-1β-induced chondrocyte apoptosis. The combined drug treatment alleviated the progression of osteoarthritis by inhibiting the IL-17/PI3K/AKT/NF-κB pathway. In addition, in vivo experiments showed that the combined administration could improve the further deterioration of the osteoarthritis rat model.

CONCLUSIONS

The combined administration of parecoxib and ilomastat to inhibit IL-17/PI3K/AKT/NF-κB transduction is beneficial to reduce the infiltration of inflammatory factors and matrix metalloproteinases in osteoarthritis.

Exploring Proteases as Alternative Molecular Targets to Tackle Inflammation in Cystic Fibrosis Respiratory Infections

Cystic fibrosis (CF) is characterized by chronic respiratory infections and excessive inflammation, driven by both host- and pathogen-derived proteases. The dysregulated activity of proteolytic enzymes such as neutrophil elastase (NE), cathepsin G, and matrix metalloproteases (MMPs) degrades lung tissue, exacerbates airway remodeling, and perpetuates inflammatory cycles. Concurrently, bacterial proteases from pathogens such as Pseudomonas aeruginosa and Staphylococcus aureus contribute to immune evasion and tissue destruction, compounding disease severity. Despite advances in antimicrobial and anti-inflammatory therapies, protease-driven lung damage remains a critical challenge. This review examines the dual role of host and bacterial proteases in CF pathophysiology, highlighting emerging protease-targeted therapies aimed at mitigating lung damage and inflammation. Strategies explored include the inhibition of NE, MMPs, and bacterial proteases, with a focus on innovative therapeutic approaches such as dual-function inhibitors, biologics, and advanced drug delivery systems. By restoring the protease-antiprotease balance, these interventions offer the potential to improve clinical outcomes and quality of life for CF patients.

Cystic Fibrosis Mice Are Highly Susceptible to Repeated Acute Pseudomonas aeruginosa Pneumonia after Intranasal Inoculation

Cystic fibrosis (CF) is a genetic disorder caused by mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) that controls chloride current. A number of different CFTR transgenic mouse lines have been developed and subjected to both acute and chronic infection models. However, prior studies showed no substantial differences in bacterial clearance between CF and non-CF mice after single inoculations. Here, using F508del transgenic CF mice, we examined the role of repeated acute Pseudomonas aeruginosa (PA) infection, with the second inoculation 7 days after the first. We found that CF mice were more susceptible to PA infection than non-CF mice following the second inoculation, with non-CF mice showing better neutrophil recruitment and effector functions. We further investigated the characteristics of lung immune cells using single-cell RNA sequencing, finding that non-CF lung neutrophils had more prominent upregulation of adhesion molecules including intercellular adhesion molecule-1 (ICAM-1) compared to CF lung neutrophils. Although people with CF are often colonized with bacteria and have high numbers of neutrophils in the airways during chronic infection, these data suggest that CF neutrophils have deficient effector functions in the setting of repeated acute infection.

Polymyxin B sulfate inhalable microparticles with high-lectin-affinity sugar carriers for efficient treatment of biofilm-associated pulmonary infections

Pulmonary infections caused by multidrug-resistant bacteria have become a significant threat to human health. Bacterial biofilms exacerbate the persistence and recurrence of pulmonary infections, hindering the accessibility and effectiveness of antibiotics. In this study, a dry powder inhalation (DPI) consisting of polymyxin B sulfate (PMBS) inhalable microparticles and high-lectin-affinity (HLA) sugar (i.e., raffinose) carriers was developed for treating pulmonary infections and targeting bacterial lectins essential for biofilm growth. The formulated PMBS-HLA DPIs exhibited particle sizes of approximately 3 μm, and surface roughness varied according to the drug-to-carrier ratio. Formulation F5 (PMBS: raffinose = 10:90) demonstrated the highest fine particle fraction (FPF) value (64.86%), signifying its substantially enhanced aerosol performance, potentially attributable to moderate roughness and smallest mass median aerodynamic particle size. The efficacy of PMBS-HLA DPIs in inhibiting biofilm formation and eradicating mature biofilms was significantly improved with the addition of raffinose, suggesting the effectiveness of lectin-binding strategy for combating bacterial biofilm-associated infections. In rat models with acute and chronic pulmonary infections, F5 demonstrated superior bacterial killing and amelioration of inflammatory responses compared to spray-dried PMBS (F0). In conclusion, our HLA carrier-based formulation presents considerable potential for the efficient treatment of multidrug-resistant bacterial biofilm-associated pulmonary infections.

Bacterial protease alleviate chronic liver fibrosis induced by thioacetamide through suppression of hepatic stellate cells consequently decrease its proliferative index

In chronic liver diseases, liver fibrosis occurs due to excessive extracellular matrix (ECM) protein accumulation. Approximately 2 million deaths occur yearly due to liver disease, while cirrhosis is the 11th most common cause of death. Therefore, newer compounds or biomolecules must be synthesized to treat chronic liver diseases. In this aspect, the present study focuses on the assessment of the anti-inflammatory and antioxidant impact of Bacterial Protease (BP) produced by a new mutant strain of bacteria (Bacillus cereus S6-3/UM90) and 4,4'-(2,5-dimethoxy-1,4-phenylene) bis (1-(3-ethoxy phenyl)-1H-1,2,3-triazole) (DPET) in the treatment of early stage of liver fibrosis induced by thioacetamide (TAA). Sixty male rats were divided into six groups, ten rats each as follows: (1) Control group, (2) BP group, (3) TAA group, (4) TAA-Silymarin (S) group, (5) TAA-BP group, and (6) TAA-DPET group. Liver fibrosis significantly elevated liver function ALT, AST, and ALP, as well as anti-inflammatory interleukin 6 (IL-6) and VEGF. The oxidative stress parameters (MDA, SOD, and NO) were significantly increased with a marked reduction in GSH. Expression of MAPK and MCP-1 was unregulated in the TAA group, with downregulation of Nrf₂ was observed. TAA caused histopathological alterations associated with hepatic vacuolation and fibrosis, increasing collagen fibers and high immuno-expression of VEGF. On the other hand, treatment with BP successfully improved the severe effects of TAA on the liver and restored histological architecture. Our study concluded the protective potentials of BP for attenuating liver fibrosis and could be used as adjuvant therapy for treating hepatic fibrosis.

Cellular Nanodiscs Made from Bacterial Outer Membrane as a Platform for Antibacterial Vaccination

Vaccination has become an increasingly attractive strategy for protecting against antibiotic-resistant infections. Nanovaccines based on the outer membrane from Gram-negative bacteria are appealing due to their multiantigenic nature and inherent immunogenicity. Here, we develop cellular nanodiscs made of bacterial outer membrane (OM-NDs), as a platform for antibacterial vaccination. Using Pseudomonas aeruginosa as a model pathogen, the resulting OM-NDs can effectively interact with antigen-presenting cells, exhibiting accelerated uptake and an improved capacity for immune stimulation. With their small size, the OM-NDs are also capable of efficiently transporting to the lymph nodes after in vivo administration. As a result, the nanovaccine is effective at eliciting potent humoral and cellular immune responses against P. aeruginosa. In a murine model of pneumonia, immunization with OM-NDs confers strong protection against subsequent lung infection, resulting in improved survival, reduced bacterial loads, and alleviation of immune overactivation. Overall, this report illustrates the advantages of cellular nanodiscs, which can be readily generalized to other pathogens and may be applied toward other biomedical applications.

Discovery of Pyrrolidine-2,3-diones as Novel Inhibitors of P. aeruginosa PBP3

The alarming threat of the spread of multidrug resistant bacteria currently leaves clinicians with very limited options to combat infections, especially those from Gram-negative bacteria. Hence, innovative strategies to deliver the next generation of antibacterials are urgently needed. Penicillin binding proteins (PBPs) are proven targets inhibited by β-lactam antibiotics. To discover novel, non-β-lactam inhibitors against PBP3 of Pseudomonas aeruginosa, we optimised a fluorescence assay based on a well-known thioester artificial substrate and performed a target screening using a focused protease-targeted library of 2455 compounds, which led to the identification of pyrrolidine-2,3-dione as a potential scaffold to inhibit the PBP3 target. Further chemical optimisation using a one-pot three-component reaction protocol delivered compounds with excellent target inhibition, initial antibacterial activities against P. aeruginosa and no apparent cytotoxicity. Our investigation revealed the key structural features; for instance, 3-hydroxyl group (R²) and a heteroaryl group (R¹) appended to the N-pyrroldine-2,3-dione via methylene linker required for target inhibition. Overall, the discovery of the pyrrolidine-2,3-dione class of inhibitors of PBP3 brings opportunities to target multidrug-resistant bacterial strains and calls for further optimisation to improve antibacterial activity against P. aeruginosa.