Daily Ards Research Analysis
Three ARDS-focused studies advance mechanistic and translational understanding: (1) endothelial–neutrophil Mac-1 adhesion is essential for NET formation and its blockade attenuates sepsis-driven lung injury; (2) MFGE8 restrains endothelial-to-mesenchymal transition via BMP/Smad signaling, correlating with survival in ARDS and reducing fibrosis in vivo; (3) recombinant antithrombin mitigates LPS-induced lung injury by suppressing the IL-17A/NF-κB axis. Together, they nominate actionable immunovas
Summary
Three ARDS-focused studies advance mechanistic and translational understanding: (1) endothelial–neutrophil Mac-1 adhesion is essential for NET formation and its blockade attenuates sepsis-driven lung injury; (2) MFGE8 restrains endothelial-to-mesenchymal transition via BMP/Smad signaling, correlating with survival in ARDS and reducing fibrosis in vivo; (3) recombinant antithrombin mitigates LPS-induced lung injury by suppressing the IL-17A/NF-κB axis. Together, they nominate actionable immunovascular targets for ARDS.
Research Themes
- Neutrophil extracellular traps and endothelial adhesion in sepsis-induced ARDS
- Endothelial-to-mesenchymal transition and fibrosis regulation in acute lung injury
- Immunomodulatory targeting of IL-17A/NF-κB signaling in ARDS
Selected Articles
1. MFGE8 regulates the EndoMT of HLMECs through the BMP signaling pathway and fibrosis in acute lung injury.
Serum MFGE8 is reduced in ARDS and higher levels associate with better survival. MFGE8 restrains LPS-induced EndoMT in HLMECs via BMP/Smad signaling and reduces pulmonary fibrosis and EndoMT in a mouse ALI model, nominating MFGE8 as a biomarker and therapeutic target.
Impact: This study links a measurable human biomarker to mechanistic control of EndoMT and fibrosis with in vivo efficacy, bridging pathophysiology and therapeutic potential in ARDS.
Clinical Implications: MFGE8 could aid risk stratification in ARDS and represents a candidate for anti-fibrotic therapy to limit EndoMT-driven remodeling after acute lung injury.
Key Findings
- Serum MFGE8 levels were significantly decreased in ARDS patients; higher levels correlated with better survival.
- rhMFGE8 attenuated LPS-induced EndoMT in HLMECs (↑CD31, ↓α-SMA), reducing invasion and migration.
- MFGE8 knockdown activated BMP/Smad1/5-Smad4 signaling and Snail, while rhMFGE8 inhibited these pathways.
- In vivo, rhMFGE8 ameliorated pulmonary fibrosis and EndoMT in a mouse acute lung injury model.
Methodological Strengths
- Integrated human ARDS biomarker analysis with in vitro mechanistic dissection and in vivo validation.
- Multi-platform pathway interrogation (immunofluorescence, western blot, qRT-PCR) targeting BMP/Smad and Snail.
Limitations
- Clinical cohort size and adjustment for confounders were not detailed.
- Functional outcomes were limited to surrogate markers; long-term pulmonary function was not assessed.
Future Directions: Validate MFGE8 as a prognostic biomarker in large, multicenter ARDS cohorts; optimize dosing and timing of rhMFGE8; and test efficacy in sepsis-induced ARDS models.
BACKGROUND: To investigate the effects and mechanisms of MFGE8 on LPS-induced endothelial-to-mesenchymal transition (EndoMT) and pulmonary fibrosis in human lung microvascular endothelial cells (HLMECs) and a mouse model of acute lung injury. METHODS: Serum MFGE8 levels were compared between ARDS patients and controls. In vitro, HLMECs were treated with LPS, siRNA targeting MFGE8, and recombinant human MFGE8 (rhMFGE8).HLMEC morphology, invasion, migration, and EndoMT markers (CD31, ɑ-SMA) were evaluated. BMP/Smad1/5-Smad4 signaling and Snail expression were assessed via immunofluorescence, western blotting, and qRT-PCR. In vivo, rhMFGE8 effects on pulmonary fibrosis and EndoMT were analyzed in a mouse model of acute lung injury. RESULTS: MFGE8 levels were significantly reduced in ARDS patients, with higher levels correlating to better survival. In vitro, rhMFGE8 improved HLMEC morphology, reduced invasion and migration, and attenuated LPS-induced EndoMT by increasing CD31 and decreasing α-SMA. MFGE8 knockdown increased BMP/Smad1/5-Smad4 signaling and Snail expression, while rhMFGE8 inhibited these effects. In vivo, rhMFGE8 ameliorated pulmonary fibrosis and EndoMT in mice. CONCLUSIONS: MFGE8 regulates LPS-induced EndoMT in HLMECs via the BMP/Smad1/5-Smad4 pathway and protects against pulmonary fibrosis in acute lung injury, suggesting it as a therapeutic target for ALI and ARDS.
2. Mac-1 blockade impedes adhesion-dependent neutrophil extracellular trap formation and ameliorates lung injury in LPS-induced sepsis.
Direct adhesion of neutrophils to endothelial cells via Mac-1 is required for NET formation in response to septic stimuli. Mac-1 blockade curtails NET release and ameliorates endothelial injury and lung damage in LPS sepsis, identifying Mac-1 as a tractable therapeutic target.
Impact: Uncovers a specific endothelial–neutrophil adhesion pathway (Mac-1) that drives NETosis and lung injury, providing a precise immunovascular target for ARDS secondary to sepsis.
Clinical Implications: Therapies inhibiting Mac-1 could reduce NET-driven endothelial injury and potentially prevent or mitigate sepsis-associated ARDS, pending safety and infection-control evaluations.
Key Findings
- Neutrophil adhesion to endothelial cells is essential for NET formation in response to LPS, LTA, and septic plasma.
- Blocking Mac-1 impedes NET formation, whereas inhibiting PSGL-1 or LFA-1 does not.
- Adhesion-dependent NETosis requires extracellular Ca2+ influx and PAD4-mediated histone H3 citrullination; Mac-1 blockade does not alter Ca2+ influx.
- In LPS-induced sepsis mice, Mac-1 blockade reduced NETs, inflammatory cytokines, endothelial damage, and lung injury.
Methodological Strengths
- Combined in vitro EC–neutrophil co-culture with in vivo LPS sepsis model for convergent evidence.
- Specificity testing across adhesion molecules and mechanistic readouts (Ca2+ influx, PAD4/H3 citrullination).
Limitations
- Relies on LPS models that may not capture the heterogeneity of clinical sepsis and ARDS.
- Survival outcomes and effects on host defense against infection were not reported.
Future Directions: Evaluate Mac-1 inhibitors in polymicrobial and pneumonia models, assess survival and infection risk, and explore translational candidates or repurposed agents targeting Mac-1.
BACKGROUND: Sepsis is a common critical condition that can lead to multiple organ injury. Sepsis-induced acute respiratory distress syndrome (ARDS) is frequently an important cause of poor prognosis and is associated with high mortality rates, despite existing therapeutic interventions. Neutrophil infiltration and extracellular traps (NET) are implicated in acute lung injury (ALI) and ARDS following sepsis. As circulating neutrophils infiltrate infected tissues, they come into direct contact with vascular endothelial cells (ECs). Although the ability of NETs to induce endothelial damage is well established, the specific role of direct EC-neutrophil interactions in NET formation and lung injury during sepsis is not fully understood. METHODS: In this study, NET formation was assessed when neutrophils were co-culture with ECs or separated from them and stimulated with phorbol 12-myristate 13-acetate (PMA), lipopolysaccharide (LPS), lipoteichoic acid (LTA), or septic plasma. RESULTS: We found that adhesion of neutrophils on ECs is critical in NET formation in response to LPS, LTA, or septic plasma in vitro. Blocking the macrophage-1 antigen (Mac-1) impeded NET formation, while inhibiting P-selectin glycoprotein ligand-1 (PSGL-1) or leukocyte function-associated antigen-1 (LFA-1) did not. This adhesion-dependent NET formation was reliant on the influx of extracellular calcium and peptidylarginine deiminase 4 (PAD4)-mediated citrullination of histone H3. However, Mac-1 blockade did not alter calcium influx. In a murine model of LPS-induced sepsis, Mac-1 blockade reduced NET release, lowered inflammatory cytokine levels, mitigated endothelial damage, and attenuated lung injury. CONCLUSION: Our findings offer insights into the critical role of EC-neutrophil direct contact in NET formation during sepsis and propose Mac-1 as a potential therapeutic target.
3. Recombinant Antithrombin Alleviated Pulmonary Injury and Inflammation in LPS-Induced ARDS by Inhibiting IL17a/NF-κB Signaling.
Recombinant antithrombin reduced lung injury, permeability, inflammatory cytokines, immune infiltration, and NLRP3 activation in LPS-induced ARDS. rAT downregulated IL-17A and inhibited NF-κB; exogenous IL-17A blunted rAT efficacy, implicating the IL-17A/NF-κB axis as a key mechanism.
Impact: Identifies a tractable immunomodulatory mechanism for a repurposable agent (rAT) in ARDS, linking IL-17A suppression to NF-κB inhibition and reduced lung injury.
Clinical Implications: rAT may be repurposed for sepsis-induced ARDS to dampen IL-17A/NF-κB-driven inflammation; dosing, timing, and safety require clinical evaluation.
Key Findings
- rAT alleviated lung injury and reduced alveolar permeability in LPS-induced ARDS mice.
- rAT decreased serum inflammatory cytokines, immune cell infiltration, and NLRP3 inflammasome activation.
- rAT lowered Th17 proportions and IL-17A expression and inhibited NF-κB signaling in lung tissues.
- Exogenous IL-17A administration attenuated the protective effects of rAT, supporting IL-17A/NF-κB as the effector axis.
Methodological Strengths
- Mechanistic rescue using exogenous IL-17A strengthens causal inference for the IL-17A/NF-κB axis.
- Comprehensive immune phenotyping with pathway enrichment (GO/KEGG/GSEA) and protein-level validation.
Limitations
- Single-species, single-injury model; human translational relevance remains to be demonstrated.
- No dosing optimization, pharmacokinetics, or safety/tolerability data presented.
Future Directions: Test rAT in pneumosepsis and ventilator-induced injury models; define dose–response and timing; and consider early-phase clinical trials targeting IL-17A/NF-κB signatures.
BACKGROUND: Recombinant antithrombin (rAT) has been shown to protect lungs from ARDS and modulate immune responses, but its anti-inflammatory mechanisms remain unclear. This study aimed to explore the immunomodulatory effects and mechanisms of rAT in LPS-induced ARDS mice. METHODS: ARDS mouse model was established by intraperitoneally administration of 20 mg/kg LPS. After 3 hours of LPS administration, rAT or PBS was injected intravenously. Lung injury, alveolar permeability, serum inflammatory cytokines, immune cell infiltration in lung tissue, and the proportion of Th17 were assessed 36 hours after rAT administration. The functional roles of the differential expressed genes (DEGs), obtained from LPS-induced ARDS mice treated with or without rAT, were analyzed by GO, KEGG and GSEA enrichment analysis. The activation of NF-κB and NLRP3 inflammasome was evaluated by Western blot and immunofluorescence staining. RESULTS: We found that rAT alleviated lung injury, reduced pulmonary permeability, decreased serum inflammatory cytokines, and suppressed immune cell infiltration and NLRP3 inflammasome activation. Moreover, rAT decreased the proportion of Th17 cells in lung tissues and peripheral blood, downregulated IL17a expression, and inhibited NF-κB signaling pathway in lung tissues. Additionally, the administration of IL-17A diminished the efficacy of rAT in mitigating lung injury, suppressing the immune response, and inhibiting the activation of the NF-κB signaling pathway in LPS-induced ARDS mice. CONCLUSION: The findings of this study suggest that rAT alleviates lung injury and suppresses inflammatory responses by inhibiting the IL17a/NF-κB signaling axis, suggesting that rAT may serve as a potential therapeutic agent for mitigating pulmonary inflammation and improving the prognosis of ARDS induced by sepsis. Furthermore, this study provides important research data and theoretical basis for the clinical translation and application of rAT.