Daily Respiratory Research Analysis
Three impactful respiratory studies stand out today: a Nature Communications mechanistic study reveals that the CXCL8/MAPK/hnRNP-K axis is hijacked by EV-D68, rhinovirus, and influenza to enhance replication; a multicenter pragmatic RCT in Intensive Care Medicine shows rapid syndromic PCR improves antibiotic stewardship in HAP/VAP though non-inferiority for clinical cure was not demonstrated; and a Respiratory Research methods paper establishes TiProtec-based cold storage preserving human precis
Summary
Three impactful respiratory studies stand out today: a Nature Communications mechanistic study reveals that the CXCL8/MAPK/hnRNP-K axis is hijacked by EV-D68, rhinovirus, and influenza to enhance replication; a multicenter pragmatic RCT in Intensive Care Medicine shows rapid syndromic PCR improves antibiotic stewardship in HAP/VAP though non-inferiority for clinical cure was not demonstrated; and a Respiratory Research methods paper establishes TiProtec-based cold storage preserving human precision-cut lung slices up to 14 days, enabling on-demand lung research.
Research Themes
- Host–virus interaction mechanisms in respiratory infections
- Rapid diagnostics and antibiotic stewardship in ICU pneumonia
- Advanced ex vivo human lung models and tissue preservation
Selected Articles
1. The CXCL8/MAPK/hnRNP-K axis enables susceptibility to infection by EV-D68, rhinovirus, and influenza virus in vitro.
This mechanistic study shows that CXCL8 engagement of CXCR1/2 activates MAPK signaling, driving hnRNP‑K cytoplasmic translocation and enhanced recognition of viral RNA, thereby promoting EV‑D68 replication, with similar effects in influenza and rhinovirus. Genetic or pharmacologic disruption of CXCL8/CXCR1/2 reduces viral replication in vitro, positioning the axis as a potential pan‑respiratory antiviral target.
Impact: It identifies a conserved host signaling axis co‑opted by multiple respiratory viruses, offering a unifying mechanism and a druggable target with broad antiviral potential.
Clinical Implications: CXCL8/CXCR1/2 or downstream MAPK/hnRNP‑K modulation could be explored as host-directed antivirals against diverse respiratory viruses. Caution is needed to balance anti-inflammatory effects with essential immune functions when targeting CXCL8 signaling.
Key Findings
- Silencing CXCL8 or CXCR1/2 significantly reduced EV‑D68 replication in vitro.
- CXCL8 signaling activated MAPK and drove nuclear-to-cytoplasmic translocation of hnRNP‑K, enhancing viral RNA recognition and 5′UTR function.
- The CXCL8/MAPK/hnRNP‑K axis also facilitated replication of influenza virus and rhinovirus, indicating a conserved pro‑viral pathway.
Methodological Strengths
- Mechanistic dissection across multiple respiratory viruses demonstrating pathway conservation
- Use of genetic knockdown and receptor targeting to validate causality
Limitations
- In vitro cell-based experiments without in vivo validation
- Potential off-target or pleiotropic effects when modulating CXCL8/MAPK pathways not fully characterized
Future Directions: Evaluate CXCR1/2 or MAPK inhibitors for antiviral efficacy in vivo; investigate tissue-specific roles and safety of CXCL8-axis modulation; assess synergy with direct-acting antivirals.
Respiratory viruses pose an ongoing threat to human health with excessive cytokine secretion contributing to severe illness and mortality. However, the relationship between cytokine secretion and viral infection remains poorly understood. Here we elucidate the role of CXCL8 as an early response gene to EV-D68 infection. Silencing CXCL8 or its receptors, CXCR1/2, impedes EV-D68 replication in vitro. Upon recognition of CXCL8 by CXCR1/2, the MAPK pathway is activated, facilitating the translocation of nuclear hnRNP-K to the cytoplasm. This translocation increases the recognition of viral RNA by hnRNP-K in the cytoplasm, promoting the function of the 5' untranslated region in the viral genome. Moreover, our investigations also reveal the importance of the CXCL8 signaling pathway in the replication of both influenza virus and rhinovirus. In summary, our findings hint that these viruses exploit the CXCL8/MAPK/hnRNP-K axis to enhance viral replication in respiratory cells in vitro.
2. INHALE WP3, a multicentre, open-label, pragmatic randomised controlled trial assessing the impact of rapid, ICU-based, syndromic PCR, versus standard-of-care on antibiotic stewardship and clinical outcomes in hospital-acquired and ventilator-associated pneumonia.
In a pragmatic, multicenter RCT (n=554), rapid ICU-based syndromic PCR with optional guidance increased appropriate and proportionate antibiotic use at 24 hours by 21% versus standard care, but did not demonstrate non-inferiority for 14-day clinical cure. Secondary outcomes (mortality, ΔSOFA) modestly favored standard care without statistical significance.
Impact: This trial provides high-quality evidence on real-world implementation of rapid multiplex PCR in ICU pneumonia, quantifying stewardship benefits while highlighting unresolved questions about clinical cure.
Clinical Implications: Rapid PCR can be incorporated to improve early antibiotic appropriateness in HAP/VAP, but clinicians should monitor patient trajectories closely and avoid overreliance on diagnostics for de-escalation until clinical effectiveness on cure is clarified.
Key Findings
- Appropriate and proportionate antibiotic use at 24 h improved to 76.5% with rapid PCR versus 55.9% with standard care (difference 21%; 95% CI 13–28%).
- Non-inferiority for 14-day clinical cure was not demonstrated (56.7% vs 64.5%; difference −6%, 95% CI −15 to 2%).
- Secondary outcomes (mortality, ΔSOFA) trended in favor of standard care but without clear statistical significance.
Methodological Strengths
- Pragmatic multicentre randomized design including adult and pediatric ICU populations
- Clinically relevant co-primary outcomes with ITT analysis
Limitations
- Open-label design with potential performance bias
- Optional adherence to prescribing guidance and heterogeneous implementation across sites
Future Directions: Cluster-randomized or stepped-wedge effectiveness trials assessing standardized PCR-guided algorithms on patient-centered outcomes (cure, mortality) and antimicrobial resistance trajectories.
PURPOSE: INHALE investigated the impact of seeking pathogens by PCR on antibiotic stewardship and clinical outcomes in hospital-acquired and ventilator-associated pneumonia (HAP and VAP). METHODS: This pragmatic multicentre, open-label RCT enrolled adults and children with suspected HAP and VAP at 14 ICUs. Patients were randomly allocated to standard of care, or rapid in-ICU syndromic PCR coupled with optional prescribing guidance. Co-primary outcomes were superiority in antibiotic stewardship at 24 h and non-inferiority in clinical cure of pneumonia 14 days post-randomisation. Secondary outcomes included mortality, ICU length of stay and evolution of clinical scores. RESULTS: 554 eligible patients were recruited from 5th July 2019 to 18th August 2021, with a COVID-enforced pause from 16th March 2020 and 9th July 2020. Data were analysed for 453 adults and 92 children (68.4% male; 31.6% female). ITT analysis showed 205/268 (76.5%) reviewable intervention patients receiving antibacterially appropriate and proportionate antibiotics at 24 h, versus 147/263 (55.9%) standard-of-care patients (estimated difference 21%; 95% CI 13-28%). However, only 152/268 (56.7%) intervention patients were deemed cured of pneumonia at 14 days, versus 171/265 (64.5%) standard-of-care patients (estimated difference - 6%, 95% CI - 15 to 2%; predefined non-inferiority margin -13%). Secondary mortality and ΔSOFA outcomes narrowly favoured the control arm, without clear statistical significance. CONCLUSIONS: In-ICU PCR for pathogens resulted in improved antibiotic stewardship. However, non-inferiority was not demonstrated for cure of pneumonia at 14 days. Further research should focus on clinical effectiveness studies to elucidate whether antibiotic stewardship gains achieved by rapid PCR can be safely and advantageously implemented.
3. Cold storage of human precision-cut lung slices in TiProtec preserves cellular composition and transcriptional responses and enables on-demand mechanistic studies.
Using TiProtec, human precision-cut lung slices retained viability, metabolic activity, cellular composition, and transcriptomes for up to 14 days without significant senescence, while remaining responsive to fibrotic stimuli. This enables flexible scheduling and wider access to high-quality ex vivo human lung models for functional and mechanistic studies.
Impact: A scalable preservation method for human lung tissue slices lowers logistical barriers, standardizes quality, and is likely to be widely adopted across respiratory biology, fibrosis, infection, and pharmacology research.
Clinical Implications: While not directly clinical, this platform accelerates translational studies (e.g., antifibrotic and anti-infective testing) by providing stable, human-relevant ex vivo models, potentially improving preclinical-to-clinical predictability.
Key Findings
- TiProtec preserved hPCLS viability, metabolic activity, cellular composition, and transcriptomes for up to 14 days.
- Cold storage in TiProtec downregulated cell death/inflammation/hypoxia pathways and upregulated oxidative stress–protective pathways.
- Cold-stored hPCLS remained functionally responsive to fibrotic stimuli, inducing ECM genes (fibronectin, COL1) and α‑SMA.
Methodological Strengths
- Combined viability, histology, bulk RNA-seq, and functional fibrosis assays for comprehensive validation
- Comparative evaluation against common media and TiProtec variants
Limitations
- Validated mainly up to 14 days; longer storage requires further study
- Peritumor control tissue sources may vary; single-center tissue procurement
Future Directions: Standardize protocols across centers, extend to diseased lungs (e.g., IPF, COPD), and test infection models to evaluate antiviral/antibacterial interventions post-storage.
BACKGROUND: Human precision-cut lung slices (hPCLS) are a unique platform for functional, mechanistic, and drug discovery studies in the field of respiratory research. However, tissue availability, generation, and cultivation time represent important challenges for their usage. Therefore, the present study evaluated the efficacy of a specifically designed tissue preservation solution, TiProtec, complete or in absence (-) of iron chelators, for long-term cold storage of hPCLS. METHODS: hPCLS were generated from peritumor control tissues and stored in DMEM/F-12, TiProtec, or TiProtec (-) for up to 28 days. Viability, metabolic activity, and tissue structure were determined. Moreover, bulk-RNA sequencing was used to study transcriptional changes, regulated signaling pathways, and cellular composition after cold storage. Induction of cold storage-associated senescence was determined by transcriptomics and immunofluorescence (IF). Finally, cold-stored hPCLS were exposed to a fibrotic cocktail and early fibrotic changes were assessed by RT-qPCR and IF. RESULTS: Here, we found that TiProtec preserves the viability, metabolic activity, transcriptional profile, as well as cellular composition of hPCLS for up to 14 days. Cold storage did not significantly induce cellular senescence in hPCLS. Moreover, TiProtec downregulated pathways associated with cell death, inflammation, and hypoxia while activating pathways protective against oxidative stress. Cold-stored hPCLS remained responsive to fibrotic stimuli and upregulated extracellular matrix-related genes such as fibronectin and collagen 1 as well as alpha-smooth muscle actin, a marker for myofibroblasts. CONCLUSIONS: Optimized long-term cold storage of hPCLS preserves their viability, metabolic activity, transcriptional profile, and cellular composition for up to 14 days, specifically in TiProtec. Finally, our study demonstrated that cold-stored hPCLS can be used for on-demand mechanistic studies relevant for respiratory research.