Daily Respiratory Research Analysis
Analyzed 80 papers and selected 3 impactful papers.
Summary
Analyzed 80 papers and selected 3 impactful articles.
Selected Articles
1. SIRT7-mediated desuccinylation of FOXO4 suppresses ferroptosis to alleviate LPS-induced acute lung injury.
This study defines a SIRT7–FOXO4 desuccinylation mechanism that stabilizes nuclear FOXO4, upregulates GPX4, and suppresses LPS-induced ferroptosis in alveolar epithelial cells, thereby mitigating acute lung injury in vivo. Genetic rescue (FOXO4-K139R) and pharmacologic activation (trilobatin) establish a tractable SIRT7–FOXO4 therapeutic axis.
Impact: Reveals a previously unrecognized PTM-based control of ferroptosis in ALI with both genetic and pharmacologic validation, opening a druggable axis for lung injury.
Clinical Implications: While preclinical, targeting the SIRT7–FOXO4–GPX4 pathway could inspire therapies for ALI and potentially ARDS by reducing epithelial ferroptosis and lung injury.
Key Findings
- SIRT7 desuccinylates FOXO4 at K139, blocks MDM2-mediated K48 polyubiquitination, stabilizing nuclear FOXO4.
- FOXO4 activation upregulates GPX4 and suppresses LPS-induced ferroptosis in alveolar epithelial cells.
- SIRT7 knockout worsens LPS-induced ALI in vivo; AAV6-delivered FOXO4-K139R and trilobatin-mediated SIRT7 activation ameliorate pulmonary ferroptosis and pathology.
Methodological Strengths
- Multi-tier validation including in vitro AECs, SIRT7 knockout mice, viral rescue, and pharmacologic activation.
- Site-specific PTM mapping (K139) with mechanistic linkage to ubiquitination and nuclear retention.
Limitations
- ALI was modeled with LPS; translatability to heterogeneous human ALI/ARDS phenotypes is uncertain.
- Selectivity and pharmacokinetics of trilobatin as a SIRT7 activator in the lung were not fully characterized.
Future Directions: Validate the SIRT7–FOXO4 axis in human lung tissues/biomarkers, optimize selective SIRT7 activators, and test efficacy across diverse ALI/ARDS models and infection-relevant settings.
Protein succinylation, an emerging post-translational modification (PTM), assumes a crucial role in the initiation and advancement of inflammatory diseases. Ferroptosis, propelled by lethal lipid peroxidation, is intricately associated with the pathogenesis of inflammation. Targeting ferroptosis has recently emerged as a promising therapeutic approach for acute lung injury (ALI). Nevertheless, the crosstalk between protein succinylation and ferroptosis in the regulation of ALI remains ambiguous. FOXO4, a key regulator of oxidative stress responses, is dynamically regulated by various PTMs. We identify SIRT7 as the desuccinylase essential for FOXO4 activation and nuclear localization. Mechanistically, SIRT7 desuccinylates FOXO4 at lysine 139 (K139), thereby inhibiting MDM2-mediated K48-linked polyubiquitination, which stabilizes FOXO4 and maintains FOXO4 nuclear retention. This consequently upregulates glutathione peroxidase 4 (GPX4) and suppresses lipopolysaccharide (LPS)-induced ferroptosis in alveolar epithelial cells (AECs). In vivo experiments demonstrated that SIRT7-knockout (SIRT7-KO) exacerbates LPS-induced ALI. Furthermore, the delivery of a FOXO4-K139R (mimicking desuccinylation) via adeno-associated virus 6 (AAV6) significantly alleviated pulmonary ferroptosis and histopathological damage in SIRT7-KO mice. Notably, pharmacological activation of SIRT7 with trilobatin (TLB) significantly attenuates ALI in LPS-challenged mice, establishing a potential therapeutic pathway for this pathology. Collectively, these findings delineate a previously unrecognized mechanism through which SIRT7 governs the nuclear retention and activation of FOXO4 via desuccinylation, establishing the SIRT7-FOXO4 axis as a potential therapeutic target and theoretical basis for ALI intervention.
2. Dysregulated MUC5B and MUC5AC impair epithelial barrier function and alter granulocyte frequency and activation in the lung and distal sites.
Airway gel-forming mucins MUC5B and MUC5AC have complementary, nonredundant roles in immune homeostasis: MUC5B limits bacterial load and neutrophilia, while both mucins are necessary to prevent eosinophilia and maintain epithelial barrier integrity. Disruption alters alarmins and innate lymphoid cell activation, reframing mucus as an immunomodulator in asthma/COPD.
Impact: Clarifies how specific airway mucins shape barrier function and granulocyte dynamics, offering mechanistic insight into mucus-driven inflammation in asthma and COPD.
Clinical Implications: Suggests that restoring balanced MUC5B/MUC5AC expression and barrier integrity could be a therapeutic angle in phenotypes with mucus-driven inflammation.
Key Findings
- In WT mice, Muc5b is ~40-fold more abundant than Muc5ac and increases with age; single-mucin deficiency induces compensatory upregulation of the other.
- MUC5B protects against increased airway bacterial load and neutrophil infiltration, while both MUC5B and MUC5AC are needed to prevent eosinophilia in lungs and distal compartments.
- Mucin disruption is linked to epithelial shedding, barrier gene dysregulation, increased epithelial permeability, altered alarmins, ILC activation; IL-33 challenge requires both mucins for normal granulocyte recruitment.
Methodological Strengths
- Use of genetically engineered mouse models with comprehensive immunophenotyping across airway and distal tissues.
- Integration of age-dependent expression analysis and IL-33 challenge to probe causality in granulocyte recruitment.
Limitations
- Findings are in murine models; direct translation to human asthma/COPD phenotypes requires validation.
- Molecular upstream regulators of mucin-driven barrier changes were not fully delineated.
Future Directions: Validate mucin–immune interactions in human airway tissues, define regulatory nodes controlling MUC5B/MUC5AC balance, and test barrier-restoring interventions in mucus-high phenotypes.
BACKGROUND: Mucus obstructs the airways in respiratory diseases where MUC5B is the major gel-forming mucin in COPD and MUC5AC-rich mucus dominates in asthma. Mucin production changes in response to inflammatory signals, but whether mucin dysregulation drives inflammation is less studied. OBJECTIVE: We sought to identify if MUC5B and MUC5AC affect immune cell composition during homeostasis and inflammation. METHODS: Immune cells in airways and distal compartments from wild type (WT), Muc5ac RESULTS: Mucin expression increased with age in WT mice, where Muc5b remained 40 times more abundant than Muc5ac, however, single-mucin deficiency resulted in compensatory increase of the other. MUC5B protected mice from increased bacterial load with neutrophil infiltration in airways, but MUC5B and MUC5AC were similarly important to prevent eosinophilia in lungs and distal compartments. Airway inflammation correlated with epithelial shedding, aberrant expression of epithelial integrity genes, increased epithelial permeability, and altered alarmins along with activation of innate lymphoid cells upon mucin disruption. Finally, IL-33 airway challenge increased Muc5b and Muc5ac where both mucins were required for normal granulocyte recruitment to lungs. CONCLUSION: MUC5B and MUC5AC play nonredundant yet complementary roles in maintaining airway immune homeostasis and regulating inflammation. Loss or imbalance of either mucin disrupts normal epithelial responses and compromises barrier integrity, potentially driving downstream changes in immune cell composition locally and systemically. It highlights an underappreciated immunomodulatory function of airway mucus which sheds new light on its role in asthma and COPD.
3. Perioperative Butorphanol for the Prevention of Postoperative Pulmonary Complications After Thoracoscopic Lung Resection: A Randomized, Double-Blind, Placebo-Controlled Trial.
In a double-blind RCT (mITT n=506), perioperative butorphanol reduced 7-day postoperative pulmonary complications after thoracoscopic lung resection (21.3% vs 32.9%; RR 0.65), mainly by lowering atelectasis and pleural effusion. Recovery quality improved with similar early safety, suggesting a pragmatic adjunct to enhance respiratory outcomes.
Impact: Provides randomized evidence for a low-cost, widely available agent to reduce PPCs after lung surgery—a common source of morbidity.
Clinical Implications: Consider perioperative butorphanol as part of enhanced recovery pathways for thoracoscopic lung resection to reduce PPCs, with attention to patient selection and multimodal analgesia.
Key Findings
- Perioperative butorphanol reduced composite 7-day PPCs versus placebo (21.3% vs 32.9%; RR 0.65; ARR 11.7%; NNT 9).
- Reductions were driven by lower incidences of atelectasis and pleural effusion.
- Secondary benefits included higher 24-h QoR-40 scores, lower opioid consumption, and slightly shorter hospital stay with similar safety.
Methodological Strengths
- Randomized, double-blind, placebo-controlled design with modified intention-to-treat analysis.
- Adequate sample size with clinically relevant, predefined composite outcome and supportive secondary endpoints.
Limitations
- Single-center study in China may limit generalizability across healthcare systems and surgical practices.
- Short follow-up window (7 days) does not capture late pulmonary complications.
Future Directions: Multicenter, registered RCTs with longer follow-up and subgroup analyses (e.g., high-risk lungs, opioid-tolerant patients) to refine indications and dosing.
PURPOSE: Postoperative pulmonary complications (PPCs) remain common after thoracoscopic lung resection. Butorphanol, a κ-opioid receptor agonist with analgesic and potential opioid-sparing properties, may influence postoperative respiratory recovery. This trial evaluated whether perioperative butorphanol reduces PPCs after elective thoracoscopic lung resection. PATIENTS AND METHODS: In this randomized, double-blind, placebo-controlled trial conducted at a tertiary teaching hospital in China from January to July 2025, adults aged 18-65 years with American Society of Anesthesiologists physical status I-III scheduled for elective thoracoscopic lung resection were assigned to receive butorphanol or placebo. The butorphanol group received an intravenous bolus of 10 μg/kg before anesthesia induction followed by 5 μg/kg/h until the end of surgery. The control group received volume-matched saline. The primary outcome was PPCs within 7 postoperative days. RESULTS: Of 520 randomized patients, 506 were included in the modified intention-to-treat analysis. PPCs occurred in 54 of 254 patients (21.3%) in the butorphanol group and 83 of 252 patients (32.9%) in the control group (relative risk, 0.65; 95% CI, 0.48-0.87; P = 0.004), corresponding to an absolute risk reduction of 11.7% and a number needed to treat of 9. The difference was mainly driven by lower rates of atelectasis and pleural effusion. Butorphanol was also associated with higher QoR-40 scores at 24 h, lower opioid consumption, and a modestly shorter hospital stay. Safety outcomes were similar between groups. CONCLUSION: Perioperative butorphanol reduced composite PPCs within 7 days after elective thoracoscopic lung resection, mainly through reductions in atelectasis and pleural effusion, without increasing early safety events.