Daily Respiratory Research Analysis
Analyzed 122 papers and selected 3 impactful papers.
Summary
Three impactful respiratory studies span translational mechanisms, advanced imaging, and biomarker-driven precision care. A multicohort analysis identifies azurocidin-1 as a mediator and marker of bronchiectasis severity and a downstream target of DPP-1 inhibition; a prospective Radiology study shows PREFUL MRI-derived ventilation/perfusion metrics predict CTD-ILD progression; and a Nature Communications study reveals an epithelial SLC39A1 zinc–autophagy axis protecting against ALI/ARDS.
Research Themes
- Neutrophil-driven airway disease: AZU1 as mediator/biomarker and DPP-1 inhibition
- Functional lung MRI (PREFUL) for prognostication in interstitial lung disease
- Zinc–autophagy signaling in epithelial defense against ALI/ARDS
Selected Articles
1. Azurocidin-1 as a mediator of bronchiectasis severity, epithelial defence, and target of dipeptidyl peptidase-1 inhibition: an international, multicohort study.
Across two bronchiectasis cohorts, higher sputum AZU1 associated with worse disease severity, lower FEV1, more exacerbations, radiologic burden, symptoms, and bacterial infection (notably Pseudomonas). AZU1 rose during bacterial/viral exacerbations and after experimental rhinovirus challenge. In vitro, AZU1 impaired ciliary function/epithelial integrity, and in WILLOW, DPP-1 inhibition produced the largest reduction in AZU1 among measured proteins.
Impact: Defines AZU1 as both a mechanistic driver and biomarker of bronchiectasis and links it to a modifiable pathway targeted by approved DPP-1 inhibition, bridging pathophysiology with therapy.
Clinical Implications: AZU1 could stratify risk and serve as a pharmacodynamic marker in bronchiectasis. Findings support DPP-1 inhibitors to reduce exacerbations and suggest monitoring AZU1 to guide precision therapy, particularly in Pseudomonas-infected patients.
Key Findings
- Higher sputum AZU1 correlated with greater bronchiectasis severity, lower %FEV1, and higher exacerbation frequency.
- AZU1 levels associated with radiologic burden, symptoms, and bacterial infection; highest with Pseudomonas aeruginosa.
- AZU1 increased during bacterial/viral exacerbations and after experimental rhinovirus A16 challenge.
- In vitro, AZU1 impaired ciliary function and epithelial integrity.
- Post-hoc WILLOW analysis: brensocatib significantly reduced airway AZU1 over 24 weeks, the most downregulated protein.
Methodological Strengths
- International multicohort design with replication across disease states (bronchiectasis, COPD) and experimental viral challenge.
- Integration of clinical, microbiome, proteomic (post-hoc RCT) and mechanistic in vitro assays.
Limitations
- Observational associations are subject to confounding; causality cannot be fully established.
- WILLOW findings are post-hoc and not powered for AZU1-centered outcomes; rhinovirus challenge sample size was small.
Future Directions: Prospective validation of AZU1-guided treatment strategies, head-to-head comparison of DPP-1 inhibitors with macrolides, and interventional studies testing whether AZU1 reduction mediates clinical benefit.
BACKGROUND: Dipeptidyl peptidase-1 (DPP1) inhibitors prevent the activation of neutrophil serine proteases and reduce exacerbations in people with bronchiectasis. We previously identified a novel effect of DPP1 inhibitors in reducing the neutrophil pseudoenzyme azurocidin-1 (AZU1). The aim of this study was to investigate the role of AZU1 in the pathophysiology of bronchiectasis. METHODS: Sputum AZU1 concentrations were analysed in multiple cohorts. These consisted of two observational cohorts of patients with bronchiectasis (EMBARC BRIDGE cohort 1 and cohort 2) and a c
2. Quantitative Phase-resolved Functional Lung MRI Prediction of Disease Progression in Connective Tissue Disease-associated Interstitial Lung Disease.
In a prospective cohort of 172 participants (predominantly female), PREFUL MRI quantified ventilation and perfusion abnormalities in CTD-ILD versus controls and predicted 1-year progression defined by physiologic, imaging, and symptom criteria. LASSO-selected functional parameters achieved meaningful AUCs, supporting PREFUL as a noninvasive prognostic tool.
Impact: Introduces a radiation-free, contrast-free functional MRI approach that adds prognostic value beyond CT and PFTs in CTD-ILD, enabling earlier risk stratification.
Clinical Implications: PREFUL MRI metrics could be integrated into CTD-ILD monitoring pathways to identify progressive phenotypes earlier and inform escalation to antifibrotic or immunomodulatory therapies.
Key Findings
- CTD-ILD patients showed reduced dynamic ventilation and perfusion on PREFUL MRI versus controls.
- PREFUL-derived functional parameters independently predicted 1-year progression defined by composite physiologic, imaging, and symptom criteria.
- LASSO feature selection yielded predictive models with clinically meaningful AUCs.
Methodological Strengths
- Prospective design with predefined, multi-domain progression endpoint and 1-year follow-up.
- Advanced quantitative MRI with multivariate modeling (LASSO) against clinical comparators.
Limitations
- Single-country study with a majority of female participants may limit generalizability.
- External validation and standardization of PREFUL metrics across scanners are needed.
Future Directions: External validation, head-to-head comparison with other functional imaging (e.g., hyperpolarized gas MRI), and integration into treatment-decision algorithms.
Background Connective tissue disease-associated interstitial lung disease (CTD-ILD) is a spatially and temporally heterogeneous disease. Determining whether CTD-ILD is in a progressive stage is crucial for guiding clinical management. Purpose To determine whether CTD-ILD is associated with ventilation and perfusion parameters quantified with phase-resolved functional lung (PREFUL) MRI and whether these functional parameters can help predict CTD-ILD progression. Materials and Methods In this prospect
3. Epithelial SLC39A1 prevents acute lung injury through zinc-mediated transcriptional activation of autophagy in male mice.
Using murine ALI models and human ARDS AT2 cells, the study identifies SLC39A1 as an epithelial zinc importer that activates TFEB/TFE3/MITF-dependent autophagy, mitigating mitochondrial damage and inflammatory cell death. Zinc supplementation could not rescue Slc39a1-deficient mice, indicating SLC39A1 is essential for the protective zinc–autophagy axis.
Impact: Reveals a previously unrecognized epithelial zinc–autophagy checkpoint controlling ALI/ARDS, providing a mechanistic basis and targets (SLC39A1–TFEB/TFE3) for therapeutic development.
Clinical Implications: Supports investigating zinc homeostasis modulation and autophagy activation as therapeutic strategies in ALI/ARDS, with biomarker development around SLC39A1 activity in AT2 cells.
Key Findings
- SLC39A1 is upregulated in AT2 cells in murine ALI and human ARDS.
- AT2-specific Slc39a1 deletion or zinc chelation worsened lung injury; overexpression or zinc supplementation attenuated injury.
- Zinc directly activated TFEB/TFE3/MITF to induce autophagy, limiting mitochondrial damage and apoptosis/pyroptosis.
- Zinc supplementation failed to rescue Slc39a1-deficient mice, positioning SLC39A1 upstream of the protective zinc–autophagy axis.
- Lc3b or Tfe3 deficiency increased injury and was not rescued by zinc, establishing pathway linearity.
Methodological Strengths
- Complementary human ARDS samples with murine genetic gain- and loss-of-function models.
- Epistasis experiments (AAV-shLc3b; Tfe3/Lc3b deficiency) delineating pathway hierarchy.
Limitations
- Preclinical study predominantly in male mice; translational safety/efficacy in humans is untested.
- Therapeutic window and off-target effects of zinc/autophagy modulation remain to be defined.
Future Directions: Develop small-molecule SLC39A1 modulators, validate AT2 SLC39A1 activity biomarkers, and test zinc–autophagy axis targeting in ALI/ARDS models with clinically relevant comorbidities.
Zinc transporters regulate intracellular zinc homeostasis, but their role in acute lung injury (ALI) or acute respiratory distress syndrome (ARDS) remains underexplored. Here, we show that the zinc transporter SLC39A1 is highly upregulated in alveolar type II (AT2) cells from male murine ALI models and patients with ARDS. AT2-specific Slc39a1 deletion or zinc chelation exacerbates lung injury, whereas overexpression or zinc supplementation attenuates it. Notably, zinc supplementation fails to res