Endogenous Ceramide 24:1 Constrains Th17-Driven Neutrophilic Inflammation by Antagonizing EP2 Signaling.
Summary
Integrated clinical lipidomics and mouse models identify a deficiency of very-long-chain ceramide 24:1 in neutrophilic asthma that correlates with disease severity. Cer24:1 supplementation mitigates airway hyperresponsiveness and neutrophilic infiltration, mechanistically by directly antagonizing PGE2-EP2 signaling on CD4+ T cells; Smpd1 knockout exacerbates Th17 pathology.
Key Findings
- Clinical lipidomics identified reduced very-long-chain ceramides, notably Cer24:1, in neutrophilic asthma correlating with disease severity.
- Cer24:1 supplementation reduced airway hyperresponsiveness and neutrophilic infiltration in a Th17-driven murine model.
- Smpd1 knockout (impaired ceramide generation) exacerbated Th17 pathology.
- Biophysical and functional assays showed Cer24:1 directly binds and antagonizes PGE2 receptor EP2 on CD4+ T cells, constraining Th17 responses.
Clinical Implications
Cer24:1 or small-molecule EP2 modulators could be explored as therapeutics for neutrophilic, steroid-refractory asthma; Cer24:1 levels may serve as a biomarker for endotype stratification.
Why It Matters
This study uncovers a previously unrecognized endogenous lipid antagonist of EP2 that restrains the Th17–neutrophil axis, offering a mechanistic target for steroid-refractory neutrophilic asthma.
Limitations
- Preclinical and translational; human interventional data are lacking.
- Heterogeneity of neutrophilic asthma endotypes and potential safety/delivery challenges for lipid supplementation were not addressed.
Future Directions
Validate Cer24:1 as a biomarker in larger human cohorts; develop and test EP2-targeted or ceramide-modulating therapeutics in early-phase clinical trials for neutrophilic asthma.
Study Information
- Study Type
- Cohort
- Research Domain
- Pathophysiology
- Evidence Level
- V - Preclinical mechanistic evidence integrating human observational data and animal experiments
- Study Design
- OTHER