Search Results (656)

Background/Objectives: The gut microbiome has an important role in immune regulation, and dietary interventions that support a balanced microbiota may help to prevent the development of allergic asthma. Dietary fibers can beneficially affect the intestinal microbiome, but due to the diversity of fiber types, the effects differ. In this study, we investigate the preventive effects of two mixes of short-chain and long-chain (1:1 and 9:1 ratio) fructo-oligosaccharides (FOS) in a mouse model of house dust mite (HDM)-induced allergic asthma. Methods: BALB/c mice received FOS-supplemented (1% w/w) diets before and during intranasal exposures to HDM. Endpoint airway hyperreactivity measurements were performed, followed by the collection of bronchoalveolar lavage fluid (BALF), lung, serum and cecum content. Fecal microbiome composition was determined by DNA sequencing and short-chain fatty acid (SCFA) levels were determined in the cecum, serum and lung. Results: Fecal microbiome analyses revealed an increased abundance of Prevotellaceae after FOS1:1 supplementation in HDM-allergic mice. Additionally, FOS1:1 protected against an HDM-induced increase in basal airway resistance. Both FOS1:1 and FOS9:1 restored the systemic acetate levels in HDM-allergic mice. The two FOS supplementations did not affect HDM-induced inflammatory cell influx in the BALF. However, FOS1:1 increased the frequency of Th1-cells and prevented an HDM-induced increase in the Th2/Th1 balance. Upon ex vivo restimulation with HDM, lung cell suspensions of FOS1:1-fed mice produced less type 2-related cytokines compared to control-supplemented mice, and FOS9:1 followed a similar pattern. Conclusions: Specific short-chain and long-chain FOS ratios differentially affect the microbiome and immune system in a mouse model with HDM-induced allergic airway inflammation. Dietary supplementation with FOS1:1 shifts the immune response away from type 2, suggesting that dietary fibers like FOS1:1 may contribute as a part of a broader strategy to modulate HDM-induced allergic asthma. Full article

Exposure to hypoxia may cause lung injury characterized by hydrostatic pulmonary edema (PE), inflammation and oxidative stress. Norepinephrine (NE) infusion can also induce lung injury with similar pathogenetic characteristics. The main questions of this study were (i) whether NE infusion aggravates hypoxia-induced pulmonary injury; (ii) whether inflammation and oxidative stress deteriorate the hypoxic PE; and (iii) whether PE and inflammation recede after three days of normoxic recovery. Ninety-eight female rats were exposed for 72 h to normoxia or normobaric hypoxia and received infusions with NaCl or NE. Some of these animals were transferred to a three-day normoxic recovery period thereafter. We performed histological and immunohistochemical analyses of the lung, determined protein concentrations in pleural fluid (PF) and bronchoalveolar lavage fluid (BALF), and evaluated hemodynamic parameters. While inflammation and oxidative stress receded after 3 days of normoxic recovery, PE did not resolve. Increased protein concentrations in PF and BALF indicated that capillary stress failure increased even further during the normoxic recovery phase, particularly in animals that had previously received an NE infusion. These results highlight the fact that inflammation does not play a causal role in the development of hypoxic PE. Full article

Airborne particulate matter (PM), particularly PM_2.5, contributes to pulmonary injury by inducing oxidative stress and inflammation. Thyme (Thymus vulgaris L.) contains bioactive compounds with anti-inflammatory, antioxidant, and expectorant properties. Here, we evaluated the dose-dependent protective effects of thyme extract (TV) against PM_2.5-induced pulmonary injury in mice, using dexamethasone (DEXA) as a reference anti-inflammatory drug. Subacute pulmonary injury was induced in male Balb/c mice via intranasal administration of PM_2.5 (1 mg/kg, twice at 48 h intervals). Mice received oral TV (50, 100, or 200 mg/kg) or DEXA (0.75 mg/kg) daily for 10 days. Assessments included lung weight, serum AST/ALT, bronchoalveolar lavage fluid (BALF) leukocyte counts, cytokines (TNF-α, IL-6), chemokines, oxidative stress markers (ROS, lipid peroxidation, antioxidant enzymes), histopathology, and mRNA expression of genes related to inflammation (PI3K/Akt, MAPK, and NF-κB), mucus production (MUC5AC, MUC5B), and apoptosis (Bcl-2, Bax). Exposure to PM_2.5 caused oxidative stress, pulmonary inflammation, mucus hypersecretion, and histopathological changes. TV treatment dose-dependently reduced leukocyte infiltration, cytokine/chemokine release, ROS generation, and mucus overproduction, while enhancing antioxidant defenses and improving tissue pathology. Effects were comparable but slightly less potent than DEXA. Notably, unlike DEXA, TV reduced mucus hyperplasia and enhanced expectorant activity. No hepatotoxicity was observed. These results indicate that thyme extract could serve as a promising natural candidate for alternative respiratory therapeutics or functional food development. Full article

Centella asiatica, a widely used medicinal herb in Oriental and increasingly Western medicine, is applied for wound healing, dermatological disorders, and gastrointestinal illness. We investigated the effects of fermented C. asiatica extract (FCAE), prepared with Lactobacillus, on airway inflammation in a murine model of chronic obstructive pulmonary disease (COPD) induced by cigarette smoke extract (CSE) and lipopolysaccharide (LPS). CSE/LPS stimulation caused marked immune cell infiltration in airways. FCAE (100 and 200 mg/kg) reduced neutrophils in the bronchoalveolar lavage fluid (BALF) by 26.03% and 70.11%, respectively, and decreased activated T cells and B cells in the lung, mediastinal lymph nodes, and Peyer’s patches, while inhibiting collagen fibrosis. FCAE significantly reduced IL-1α (32.51%), CXCL1 (47.63%), CXCL2 (45.37%), and TNF-α (39.51%) levels in the BALF compared with the control group. It also downregulated the expression of muc5ac (58.39%), CXCL1 (67.32%), CXCL2 (57.60%), and TNF-α (54.61%) and suppressed p-STAT3 activation by 50.22%. Furthermore, FCAE enhanced tracheal phenol red secretion by 229.62%, indicating expectorant activity. UPLC analysis identified nine components, which, together with FCAE, inhibited RANTES, TNF-α, and IL-6 in inflammation-induced BEAS-2B cells. Overall, FCAE attenuates immune activation and airway inflammation, supporting its potential as a candidate therapy or functional food for respiratory diseases. Full article

Der p 23 induces a high-frequency sensitization in allergic individuals. However, its allergenic activity and clinical impact are scarce. We aimed to evaluate the ability of rDer p 23 to induce allergic inflammation in a mouse model and to test IgE reactivity in humans. Female Balb/c mice were sensitized and challenged with rDer p 23 and Dermatophagoides pteronyssinus extract. Specific antibodies were determined by ELISA, inflammatory cell infiltration and goblet cells hyperplasia were evaluated by lung histology, and bronchial hyperreactivity (BHR) was assessed by the FinePoint RC System^TM and whole-body plethysmography (WBP). IgE reactivity was evaluated by ELISA, the basophils activation test (BAT) and the skin pick test (SPT) in humans. rDer p 23, produced in Escherichia coli, adopts a random coil structure, predominantly exists in a monomeric state, and exhibits high stability. rDer p 23-treated mice showed a significant increase in lung resistance and bronchial hyperreactivity, as well as in eosinophils, neutrophils, and T cell count in bronchoalveolar lavage fluid (BALF). Cytokine and antibodies profiles were biased to a Type-2 response. No significant difference was observed in group 2 Innate Lymphoid Cells (ILC-2s) in lung and regulatory T cells (Treg) in the spleen. In asthmatic individuals sensitized to D. pteronyssinus, serum IgE reactivity to rDer p 23 was 67.5%. BAT and SPT results were significantly higher in allergic patients. Our findings support the pro-allergenic role of rDer p 23 in the development of the pathological features of asthma. Full article

Background/Objectives: Obesity and hyperglycemia predispose patients to respiratory infections. Although the lung is a major organ to utilize glucose, pulmonary glucose homeostasis in type 2 diabetic (T2Dx) subjects remains poorly characterized. We hypothesized that pulmonary glucose transport would be altered during T2Dx, which would be rescued with long-term metformin treatment. Methods: T2Dx was induced by feeding mice a high-fat diet for 16 weeks, with metformin treatment administered during the final 8 weeks. Results: Glucose transporter (GLUT) protein expression and trafficking was quantified by Western blotting and the biotinylated photolabeling assay, respectively. T2Dx mice exhibited obesity, and increased glucose levels in blood and bronchoalveolar lavage (BAL) fluid. T2Dx also significantly decreased protein expression of GLUTs from Class I (i.e., GLUT-2 and -4) and class III (i.e., GLUT-10 and -12) isoforms in lung. Metformin treatment restored the protein expression of GLUT-2, -4, and -10, but not GLUT-12. Pulmonary cell surface expression of GLUT-4 and -8 was also significantly reduced in T2Dx mice and rescued by metformin. Conclusions: These findings suggest that alterations in pulmonary GLUT expression and trafficking during diabetes could contribute to the elevated airway glucose levels and severity of respiratory infections. Metformin treatment restored pulmonary glucose transport during T2Dx. Full article

Background/Objectives: Allergen-specific immunotherapy remains the only disease-modifying treatment for allergic diseases, and the use of recombinant hypoallergenic derivatives is a promising therapeutic approach. Among these, BTH2 has previously shown efficacy in an acute murine model of allergy induced by Blomia tropicalis. The present study aimed to evaluate both the efficacy and safety of BTH2 in a chronic asthma model induced by B. tropicalis. Methods: A/J male mice (n = 6) were sensitized and chronically challenged with B. tropicalis extract over four months. One group repeatedly received subcutaneous doses of BTH2 (25 µg) for three months (65 doses). Parameters of allergic airway inflammation, antibody profiles, cytokine levels, and markers of AIT success were evaluated in bronchoalveolar lavage fluid, lung tissue, serum, and splenocyte cultures. Results: Repeated BTH2 administration was well tolerated, with no signs of systemic toxicity. BTH2 significantly reduced neutrophilic and eosinophilic airway inflammation, while increasing lymphocytes and regulatory cytokines in the lungs. It suppressed IgE against B. tropicalis allergens, while inducing mucosal IgA responses and systemic IgG, which may be linked to the observed blocking antibody activity in BTH2-treated mice. The treatment also led to downregulation of Th2 cytokines and enhanced expression of regulatory and Th1-associated cytokines, especially IL-10, TGF-β and IFN-γ. Correlation matrix analyses indicated that regulatory cytokines were correlated with beneficial antibody responses and reduced inflammation. Conclusions: BTH2 shows strong therapeutic and immunomodulatory effects in a chronic asthma model induced by B. tropicalis, with a favorable safety profile. These findings support its potential for future clinical trials, including those involving patients with allergic asthma. Full article

Glycogen metabolism plays a key role in bacterial adaptation. In Streptococcus pneumoniae, the glycogen-degrading enzyme SpuA is widely conserved, but its physiological significance remains unclear. In this study, we investigated how SpuA affects bacterial growth and response to acid stress. We found that the spuA deletion strain (ΔspuA) produced more acidic metabolites under anaerobic conditions than the wild-type strain. In a mouse infection model, bronchoalveolar lavage fluid (BALF) from ΔspuA-infected mice was more acidic on day 1 post-infection, showing a lower bacterial load than wild-type infection—a finding consistent with the early growth delay observed in vitro—but the mutant later exhibited enhanced persistence at 72 h. ΔspuA strains also showed greater tolerance to formic acid and higher intake of serum amyloid A1 (SAA1), which may further contribute to their survival in acidic environments. Transcriptomic analysis revealed reduced utilization of certain amino acids, particularly cysteine, in ΔspuA strains. However, the addition of 0.05% (v/v) formic acid restored amino acid utilization in ΔspuA strains, and co-supplementation with formic acid and cysteine significantly enhanced ΔspuA growth in vitro. These findings suggest that in the absence of SpuA, S. pneumoniae shifts its metabolism toward formic acid production, which may act both as a metabolic signal and a stressor that influences bacterial gene expression. This shift is accompanied by increased expression of tRNAs and growth rescue, suggesting enhanced amino acid utilization capacity. Although our findings reveal a potential link between formic acid metabolism and amino acid utilization through tRNA regulation, further validation using metabolic flux analyses or targeted metabolomics will be required to confirm this relationship. These observations imply a metabolic adaptation that facilitates bacterial growth under low-oxygen, acidic conditions during infection. Our results also raise the possibility that SpuA plays a role in restraining bacterial overgrowth in the host, thereby promoting a more balanced coexistence between pathogen and host. Full article

Bacterial lysates have emerged as promising immunomodulatory agents that can enhance innate immune responses. Given the crucial role of macrophages in recognizing and controlling intracellular pathogens such as Mycobacterium tuberculosis, this study aimed to evaluate the immunological effects of selected bacterial lysates on human monocyte-derived macrophages (MDMs). We examined the ability of commercial bacterial lysates, Pulmonarom, Ismigen, Uro-Vaxom, and a lysate of M. tuberculosis H37 Ra (LMtb) to stimulate the production of key pro-inflammatory cytokines, including TNF-α, IL-1β, and IL-8. In addition, we investigated whether these lysates could modulate the expression of bactericidal/permeability-increasing protein (BPI), a critical antimicrobial effector, and assessed their ability to reduce the intracellular burden of mycobacteria and induce autophagy. The results demonstrate diverse immunostimulatory profiles among the lysates, highlighting differences in both inflammatory and antimicrobial responses that may be relevant for host-directed therapeutic strategies against tuberculosis. Notably, beyond the in vitro antimycobacterial activity observed for BPI, this protein was also found to be elevated in both serum and bronchoalveolar lavage fluid from patients with active TB, reflecting local and systemic immune activation. Furthermore, the reduction in BPI levels after treatment suggests its potential utility for following the dynamics of infection. Full article

Lower respiratory tract infections (LRTIs) represent a significant global health concern, and the accurate identification of pathogens is crucial for patient care. Culture-based methods are the gold standard, but their detection abilities are limited. Next-generation sequencing (NGS) offers a promising method for comprehensive microbial detection, providing valuable information for clinical practice. In this study, 144 bronchoalveolar lavage fluid samples were collected, culture-based diagnostics were performed, and bacterial microbiome profiles were generated by short-read sequencing of the V4 region of the 16S rRNA gene using Illumina technologies and long-read sequencing with Oxford Nanopore Technologies (ONT) to determine the full-length 16S rRNA gene. The most common genera detected by NGS included Streptococcus, Staphylococcus, Veillonella, Prevotella, Rothia, Enterococcus, and Haemophilus. Short-read sequencing detected cultured bacteria at the genus level in ~85% of cases, while long-read sequencing demonstrated agreement with cultured species in ~62% of cases. In three cases, long-read sequencing identified the uncommon potential lung pathogen Tropheryma whipplei not detected with traditional culturing techniques. The NGS results showed a partial overlap with culture as the current diagnostic gold standard in LRTI. Additionally, NGS detected a broader spectrum of bacteria, revealed fastidious potential pathogens, and offered deeper insights into the complex microbial ecosystem of the lungs. Full article

Neutrophils are among the first cells to be recruited to the lungs during Chlamydia pneumoniae infection in mouse models; however, their regulatory functions are not yet fully understood. This study examined the mechanisms and significance of IL-10-producing neutrophils throughout C. pneumoniae pulmonary infection in C57BL/6 mice. Our findings revealed that infection with C. pneumoniae induces IL-10 secretion in bone marrow-derived neutrophils, depending on Toll-like receptor 2 (TLR2) activation. This process involves TLR2-dependent mitochondrial reactive oxygen species (ROS) production, which triggers the endoplasmic reticulum (ER) stress pathway, including IRE1α and subsequent Xbp1 splicing. Inhibition of this pathway or depletion of neutrophils (using the 1A8 monoclonal antibody) significantly reduces IL-10 levels in bronchoalveolar lavage fluid (BALF) in vivo. Conversely, the absence of IL-10-producing neutrophils, whether through depletion or TLR2 deficiency, leads to increased IL-12p70 and IFN-γ-positive NK cells, along with decreased regulatory T cells and M2-like macrophages. This results in a lower bacterial burden in the lungs but causes more severe pulmonary damage and decreased survival rates. These findings highlight that IL-10 produced by neutrophils via the TLR2-mitochondrial ROS–ER stress pathway is essential for modulating pulmonary immune responses and maintaining immune homeostasis during C. pneumoniae infection, thereby preventing excessive inflammation and tissue damage. Full article

Idiopathic pulmonary fibrosis (IPF) is a progressive lung disease characterized by aberrant fibroblast activation, lysosomal dysfunction, and cellular senescence. Transcriptomic analyses have identified ependymin-related 1 (EPDR1) as a fibroblast-enriched gene in IPF, but its biological function remains unclear. EPDR1 expression was assessed in lung fibroblasts, lung tissues, bronchoalveolar lavage fluid (BALF), and serum from IPF patients and controls using qPCR, Western blotting, ELISA, and immunohistochemistry. Lysosomal function, autophagic flux, and senescence markers were analyzed in primary fibroblasts following siRNA-mediated EPDR1 knockdown. EPDR1 was significantly upregulated in IPF-derived fibroblasts and localized to fibrotic regions enriched with α-SMA⁺, COL1A1⁺, and FN1⁺ myofibroblasts of IPF-derived lung tissues. EPDR1 levels were markedly elevated in the BALF and serum of IPF patients and correlated with increased mortality. IPF fibroblasts exhibited reduced lysosomal acidification and impaired autophagic flux, indicated by p62 and LC3B accumulation. EPDR1 knockdown restored lysosomal function; enhanced autophagic degradation; and reduced senescence markers, including p21, p16, and SA-β-gal activity. EPDR1 drives lysosomal dysfunction and fibroblast senescence in IPF. Its elevated expression in lung tissue and biological fluids, together with its association with prognosis, highlights EPDR1 as a potential biomarker and therapeutic target in IPF. Full article

Community-acquired pneumonia (CAP) is a leading cause of death, with mortality linked to an unbalanced host response. Sirtuin (Sirt)1, a histone deacetylase, regulating metabolism and epigenetics, may be fundamental in activating the innate immune response. Sirt1 mRNA expression was significantly reduced in monocytes from CAP patients (n = 76) upon admission compared to healthy controls (n = 42), with levels returning to normal after 30 days. Pharmacological activation of Sirt1 with SRT1720 decreased LPS- and K. pneumoniae-induced IL-6 release in primary human monocytes and decreased NF-κB activation in THP1 cells. In a mouse K. pneumoniae pneumosepsis model, SRT1720 strongly reduced neutrophil influx and degranulation markers in bronchoalveolar lavage fluid, lowered pulmonary concentrations of IL-6 and TNF-α, and reduced lung pathology scores. Simultaneously, it reduced neutrophil content in liver tissue and plasma transaminase levels, alongside a trend toward reduced liver necrosis. Plasma IL-6 and TNF-α were significantly lower in SRT1720-treated mice at 42 h. Finally, while SRT1720 did not impact bacterial loads in the lungs, it reduced bacterial burden in blood, with a similar trend observed in liver homogenates. In conclusion, the Sirt1 activator SRT1720 exerts anti-inflammatory effects on human monocytes, reduces local and systemic inflammation and organ injury, and diminishes bacterial dissemination in murine pneumosepsis. Full article

Background/Objectives: The dysregulation of NLRP3 inflammasome activation has been established as a key driver of inflammatory disease pathology, which marks NLRP3 as an attractive therapeutic target. However, the clinical development of NLRP3 inhibitors such as MCC950 has been hampered by their associated toxicity profiles, highlighting an unmet clinical need. Methods: Herein, we present LMT2368, a novel urea-based NLRP3 inhibitor identified through screening of urea-based derivatives from our in-house compound library. Results: Biolayer interferometry confirmed direct binding of LMT2368 to the NLRP3 NACHT domain with a (K_D = 27.4 ± 1.2 μM which was superior to MCC950. Molecular docking studies predicted enhanced binding interactions for LMT2368, consistent with its improved biological activity. In LPS-primed macrophages, LMT2368 dose-dependently suppressed IL-1β secretion (IC50 = 0.8 μM in J774A.1 cells) and caspase-1 activation without affecting NF-κB signaling. Importantly, LMT2368 inhibited ASC oligomerization and pyroptosis while maintaining excellent safety margins (CC50 > 50 μM). In a murine model of LPS-induced acute lung injury, LMT2368 (10 mg/kg) reduced bronchoalveolar lavage fluid immune cell infiltration by 68% (p < 0.001), suppressed pro-inflammatory cytokine release (IL-1β/IL-6/TNF-α), and preserved lung histoarchitecture. Notably, LMT2368 showed selectivity for NLRP3 inhibition without affecting TNF-α/IL-6 production during TLR4 priming in monocytic cell lines. Conclusions: Together, these findings establish LMT2368 as a promising lead compound for developing safer NLRP3 inhibitors with therapeutic potential for inflammasome-driven diseases. Full article

Background: Eravacycline exhibits potent activity against multidrug-resistant pathogens and holds promise for the management of hospital-acquired and ventilator-associated pneumonia (HAP/VAP). However, sensitive and robust bioanalytical methods to quantify eravacycline in human pulmonary epithelial lining fluid (ELF) for pharmacokinetic (PK) and pulmonary penetration studies in these infections remain limited. Methodology: A simple, rapid, and sensitive LC-MS/MS method was developed for the quantification of eravacycline in bronchoalveolar lavage fluid (BALF). Using urea as a volume normalizer, ELF concentrations were calculated from the eravacycline concentrations in BALF. This method was applied in a clinical study evaluating the pulmonary penetration after intravenous infusion in patients with HAP and VAP. Results: The developed LC-MS/MS method exhibited good linearity in the range of 1–200 ng/mL for quantifying eravacycline in BALF. In BALF, intra-day precision ranged from 1.4% to 6.0%, and inter-day precision from 1.6% to 9.9%, with accuracy between 98.0% and 102.4%. Matrix effects were within 97.4% to 107.6% for BALF samples from six different individuals, with extraction recoveries ranging from 103.5% to 107.2%. Stability studies demonstrated that eravacycline remained stable under various conditions, including storage at room temperature, freeze–thaw cycles, long-term (–70 °C) storage, and post-treatment handling. The method was successfully applied to clinical samples from four HAP or VAP patients, with measured eravacycline pulmonary penetration ratios of 4.29, 17.40, 5.22 and 4.70, indicating efficient pulmonary distribution. The measured eravacycline concentrations ranged from 0.0243 to 0.0436 μg/mL in BALF. The corresponding urea-corrected ELF concentrations ranged from 0.570 to 1.617 μg/mL. Conclusions: This study described a detailed and validated method for quantifying eravacycline concentrations in ELF from patients, providing a reliable analytical approach for investigating the pulmonary distribution of eravacycline. Full article