Daily Sepsis Research Analysis
Analyzed 23 papers and selected 3 impactful papers.
Summary
Three high-impact studies advanced sepsis science across endothelial, cardiac, and perinatal domains. Mechanistic papers revealed endothelial LRG1-driven VE-cadherin ubiquitination as a tractable target in septic lung injury and identified STIM1-mediated calcium overload–mitochondria–inflammasome coupling in sepsis-induced cardiomyopathy. A large meta-analysis mapped non-linear infection risk thresholds after premature rupture of membranes, informing neonatal sepsis prevention.
Research Themes
- Endothelial barrier integrity and vascular leakage in sepsis
- Calcium homeostasis–mitochondria–inflammasome axis in sepsis-induced cardiomyopathy
- Perinatal infection risk thresholds after premature rupture of membranes
Selected Articles
1. Intracellular LRG1 recruits MARCH2 to ubiquitinate and degrade endothelial VE-cadherin in septic lung injury.
This mechanistic study reveals that endothelial intracellular LRG1 drives VE-cadherin K48-linked polyubiquitination via MARCH2, promoting proteasomal degradation and barrier failure in septic ALI. Genetic Lrg1 deletion and a PROTAC-based approach preserved VE-cadherin, reduced hyperpermeability, and mitigated lung injury in septic mice, highlighting LRG1/MARCH2 as a therapeutic axis.
Impact: Identifies a previously unrecognized, druggable pathway controlling endothelial junction stability in sepsis and demonstrates in vivo rescue using a targeted protein degradation strategy.
Clinical Implications: Targeting LRG1 or its interaction with MARCH2 could preserve VE-cadherin and reduce vascular leakage in sepsis-induced ALI/ARDS, motivating translational development of inhibitors or degraders.
Key Findings
- Endothelial intracellular LRG1 is upregulated in septic ALI and promotes VE-cadherin degradation.
- LRG1 recruits MARCH2 to catalyze K48-linked polyubiquitination of VE-cadherin at lysine 633.
- Genetic Lrg1 deletion or PROTAC-based intervention preserves VE-cadherin, reduces hyperpermeability, and mitigates lung injury in septic mice.
Methodological Strengths
- Multi-level mechanistic validation (biochemistry, genetics, and in vivo septic mouse models).
- Target engagement demonstrated with a PROTAC-based strategy in addition to genetic deletion.
Limitations
- Preclinical models; human validation of the LRG1–MARCH2–VE-cadherin axis remains to be established.
- Potential off-target effects and pharmacokinetics of PROTACs in sepsis are not addressed.
Future Directions: Validate LRG1/MARCH2 pathway activity and biomarkers in human sepsis cohorts; optimize LRG1 inhibitors/PROTACs and assess efficacy and safety in large-animal models toward early-phase trials.
Endothelial barrier dysfunction and consequent vascular injury are central contributors to acute lung injury (ALI) during sepsis. However, the underlying mechanisms remain incompletely understood, and effective therapeutic strategies targeting endothelial repair are still lacking. Here, we identify that intracellular leucine-rich α2-glycoprotein 1 (LRG1) in endothelial cells (EC) is significantly upregulated and directly promotes the degradation of vascular endothelial cadherin (VE-cadherin), a core adherens junction protein essential for maintaining vascular barrier integrity in septic ALI. Mechanistically, LRG1 recruits the E3 ubiquitin ligase membrane-associated ring-CH-type finger 2 (MARCH2) to catalyze K48-linked polyubiquitination of VE-cadherin at lysine 633, leading to its proteasomal degradation and subsequent endothelial barrier disruption. Genetic deletion of Lrg1 or pharmacological intervention with a proteolysis targeting chimera (PROTAC)-based degradation strategy significantly reduced VE-cadherin loss, alleviated endothelial hyperpermeability, and mitigated ALI in septic mice. Collectively, our study elucidates a previously unrecognized role of endothelial LRG1 in disrupting EC adherens junctions, providing novel insights into the pathogenesis of sepsis-associated injury and proposing a potential therapeutic strategy for sepsis-induced ALI and acute respiratory distress syndrome (ARDS).
2. Targeting STIM1 attenuates LPS-induced cardiac dysfunction by reshaping calcium homeostasis and mitochondrial function.
In LPS-induced sepsis models, STIM1 upregulation drives excessive store-operated Ca2+ entry, mitochondrial Ca2+ overload, Drp1-mediated fission, ROS, and NLRP3-dependent pyroptosis, culminating in cardiac dysfunction. Myocardial-specific STIM1 knockdown and BTP2 treatment ameliorated dysfunction, positioning STIM1 as a viable target in sepsis-induced cardiomyopathy.
Impact: Defines a mechanistic Ca2+–mitochondria–inflammasome axis in sepsis cardiomyopathy and demonstrates targetability via genetic and pharmacologic interventions.
Clinical Implications: Therapies dampening STIM1-mediated Ca2+ influx or downstream mitochondrial/pyroptotic signaling could mitigate cardiac dysfunction in sepsis, meriting translational studies.
Key Findings
- STIM1 is upregulated in LPS-induced sepsis and contributes to sepsis-induced cardiomyopathy.
- STIM1 enhances store-operated Ca2+ entry, causing mitochondrial Ca2+ overload, Drp1-dependent fission, ROS elevation, and NLRP3-mediated pyroptosis.
- Cardiac function improved with myocardial-specific STIM1 knockdown and with the Ca2+ influx inhibitor BTP2.
Methodological Strengths
- Integrated in vivo (rat) and in vitro cardiomyocyte experiments linking molecular mechanisms to organ function.
- Use of both genetic knockdown and pharmacologic inhibition to establish causality.
Limitations
- LPS models may not fully recapitulate polymicrobial or CLP sepsis.
- Off-target effects of BTP2 and lack of long-term survival outcomes were not addressed.
Future Directions: Validate STIM1 pathway biomarkers in human SICM, test selective STIM1/SOCE modulators, and assess effects on arrhythmia, hemodynamics, and survival in clinically relevant sepsis models.
Dysregulated calcium homeostasis and mitochondrial impairment are critical factors in the pathogenesis of sepsis-induced cardiomyopathy (SICM). STIM1 is crucial for maintaining calcium homeostasis. However, whether improving STIM1-mediated calcium handling can alleviate SICM remains unknown. This study aims to clarify the mechanism and the role of STIM1 in SICM. In this study, we first established a rat model of sepsis induced by LPS and clarified that the upregulation of STIM1 protein is associated with sepsis-induced cardiomyopathy (SICM). Myocardial-specific knockdown of STIM1 significantly improved cardiac function in septic rats. Moreover, using the calcium influx inhibitor BTP2, we elucidated that BTP2 could alleviate LPS-induced cardiomyopathy by improving calcium handling and mitochondrial function. Subsequently, we treated cardiomyocytes with LPS to explore the mechanism by which STIM1 promotes SICM. The results demonstrated that STIM1 amplifies store-operated calcium entry, triggering concomitant cytosolic and mitochondrial calcium overload. This induces Drp1-dependent mitochondrial fragmentation and dysfunction, resulting in elevated ROS production and subsequent activation of the NLRP3 inflammasome-mediated pyroptosis in cardiomyocytes, ultimately leading to LPS-induced cardiomyopathy. In conclusion, this study indicate that STIM1 promotes calcium overload, thereby facilitating mitochondrial dysfunction and ultimately resulting in pyroptosis. Targeting STIM1 may thus represent a promising therapeutic strategy for SICM.
3. Time-Threshold Dose-Response Relationship Between Duration of Premature Rupture of Membranes and Maternal, Neonatal, and Laboratory Evidence of Infection: A Systematic Review and Meta-Analysis.
Synthesizing >70,000 mother–neonate pairs, this meta-analysis demonstrates a non-linear rise in infection risks with PROM duration, with early signals at 16–18 hours and a marked inflection around 37 hours; >48 hours confers the highest risk for culture-proven neonatal sepsis. Findings argue for time-sensitive management thresholds to reduce neonatal sepsis and maternal complications.
Impact: Defines practical, data-driven time thresholds linking PROM latency to neonatal culture-proven sepsis, with clear implications for obstetric decision-making and neonatal sepsis prevention.
Clinical Implications: Consider earlier delivery or intensified surveillance once PROM exceeds 18 hours, with strong consideration for expedited management between 37–48 hours to prevent neonatal sepsis; tailor to gestational age given heterogeneity.
Key Findings
- Risk of infection increases non-linearly with PROM duration, with early-onset pneumonia risk elevated from 16 hours (AOR 1.86).
- At 18 hours, neonatal culture-proven sepsis incidence is 4.0% and maternal fever risk is markedly higher (AOR 36.6).
- A pivot at ~37 hours precedes exponential risk escalation; >48 hours is the strongest predictor of culture-proven neonatal sepsis (risk increase 8.2; p<0.001).
- Histologic chorioamnionitis was present in 39% and often clinically silent; heterogeneity (I2>60%) was driven by gestational age differences.
Methodological Strengths
- Large aggregated sample (>70,000 pairs) enabling robust dose-response modeling with restricted cubic splines.
- Two-step random-effects approach estimating continuous risk thresholds enhances clinical interpretability.
Limitations
- Substantial heterogeneity (I2>60%) driven by gestational age strata and study-level differences.
- Observational meta-analysis susceptible to residual confounding and variable definitions of infection outcomes.
Future Directions: Prospective, gestational age–stratified studies to validate thresholds; decision-analytic models balancing neonatal sepsis risk against prematurity-related harms; update guidelines incorporating non-linear risk.
OBJECTIVE: To identify the continuous dose-response relationship between the duration of premature rupture of membranes (PROM) and the probability of neonatal and maternal infectious morbidity. METHODS: This meta-analysis and systematic review synthesise data from 15 studies worldwide involving more than 70,000 mother-neonate pairs. A two-step random-effects model of PROM duration as a continuous dose, using restricted cubic splines, was used to estimate specific risk thresholds. RESULTS: The analysis established a progressive, non-linear escalation of risk. The onset of statistical risks at 16 hours is the early-onset pneumonia (Adjusted OR 1.86, 95% CI: 1.152.99). At the age of 18 hours, the incidence of culture-proven sepsis in neonates was 4.0%, and the odds ratio for maternal fever was significantly higher (AOR 36.6). The analysis of the ROC curves revealed a critical mathematical pivot point at 37 hours, after which complications escalate exponentially. Latency greater than 48 hours was the most significant independent predictor of culture-proven sepsis, with an increased risk of 8.2 (p < 0.001). Histologic chorioamnionitis was detected in 39% of mothers, and in many cases, they are clinically silent. Considerable heterogeneity (I2 > 60%) was mainly caused by gestational age disparities in cohorts of extremely preterm and term babies. CONCLUSION: PROM latency risk is not a threat but accelerates with time. Although 18 hours will be an acceptable early warning level, the range of 37 to 48 hours is a high-risk period that needs aggressive treatment. International guidelines need to be reviewed to reflect this non-linear trend, especially regarding pregnancy, where the risks of delivery are low compared to the rising risk of latency.