Daily Sepsis Research Analysis
Analyzed 28 papers and selected 3 impactful papers.
Summary
Three studies advance sepsis science across mechanistic, translational, and population levels: circadian hormones bidirectionally control endotoxin-induced inflammation with human biomarker parallels; a gut microbiota–PXR–YAP axis mediates hepatoprotection in sepsis; and neonatal UBASH3A promoter methylation links T-lymphocyte ontogeny to reduced early-onset sepsis risk. Together, they identify candidate biomarkers, therapeutic targets, and biological timing considerations.
Research Themes
- Circadian immunology and hormonal biomarkers in sepsis
- Microbiome–nuclear receptor signaling (PXR) and organ protection via YAP
- Epigenetic regulation of neonatal sepsis susceptibility (UBASH3A)
Selected Articles
1. Diurnally-Regulated Corticosterone and Melatonin Inversely Control Endotoxin-Induced Acute Immune Responses.
In mice, afternoon LPS provoked stronger neutrophil-driven inflammation and higher mortality than midnight challenges. Cyclic corticosterone amplified hyperinflammation, whereas melatonin constrained it; septic patients exhibited high cortisol/low melatonin profiles mirroring these patterns, suggesting biomarker and chronobiological implications.
Impact: Reveals a mechanistic link between circadian hormones and the magnitude of endotoxin-induced inflammation with cross-species corroboration, opening avenues for prognostication and time-of-day–aware therapies in sepsis.
Clinical Implications: Cortisol and melatonin profiling could aid risk stratification; timing of interventions and potential melatonin adjuncts warrant evaluation to mitigate hyperinflammation in sepsis.
Key Findings
- Afternoon LPS challenge increased neutrophil activation, cytotoxic mediator release, and mortality versus midnight challenge.
- Corticosterone peaks associated with enhanced LPS-induced hyperinflammation; melatonin peaks restrained inflammatory magnitude.
- Septic patients showed high cortisol and low melatonin profiles paralleling murine patterns, suggesting a prognostic marker.
Methodological Strengths
- Integrative mechanistic design linking circadian timing to immune responses in vivo.
- Cross-species validation with human biomarker profiles paralleling murine findings.
Limitations
- Human data are correlational; causality and optimal clinical intervention timing remain untested.
- LPS models may not fully recapitulate polymicrobial sepsis pathophysiology.
Future Directions: Prospective clinical validation of cortisol/melatonin as prognostic biomarkers and randomized trials of time-of-day–guided interventions or melatonin adjuncts in sepsis.
The timing of endotoxin administration in mice matters and is associated with diurnal variation in survival; however, underlying mechanisms remain poorly understood. Here, we report that afternoon LPS challenges in mice induce a robust inflammatory response involving increased neutrophil activation and release of cytotoxic mediators, causing higher mortality compared with challenges at midnight. Mechanistically, the cyclic patterns of corticosterone and melatonin hormones differentially modulate neutrophil responses. The afternoon corticosterone peak was associated with heightened incidence and severity of LPS-induced hyperinflammation. Conversely, higher melatonin levels at midnight conferred protection to challenged mice by restraining the magnitude of inflammation. High cortisol and low melatonin profiles detected in septic patients mirror those observed in mice and suggest a novel prognostic marker for sepsis. Our study unveils a regulatory network that links light/dark signals and circadian-regulated hormones to the intensity of the host's inflammatory response to infection.
2. Gut microbiota affects the role of mPXR agonist PCN in alleviating sepsis-induced liver injury by regulating YAP activation.
In CLP and LPS sepsis models, PCN pretreatment protected the liver via PXR activation, but this effect was lost after microbiota depletion and restored by FMT from PCN-treated donors. Mechanistically, the gut microbiota facilitated YAP pathway activation, positioning a microbiota–PXR–YAP axis as a driver of hepatoprotection.
Impact: Defines a causal microbiota–nuclear receptor–effector pathway (PXR–YAP) for organ protection in sepsis, using ABX depletion and FMT for mechanistic inference, highlighting translational targets.
Clinical Implications: Suggests therapeutic strategies combining PXR modulation with microbiota-directed interventions (e.g., tailored probiotics/FMT) and YAP pathway targeting to mitigate sepsis-induced liver injury; human-relevant PXR agonists and safety need evaluation.
Key Findings
- Antibiotic-mediated microbiota depletion abrogated PCN’s hepatoprotective effects in septic mice.
- FMT from PCN-treated donors restored liver protection and enhanced YAP activation in recipient septic mice.
- PCN-activated PXR reshaped gut microbiota composition and promoted YAP signaling in sepsis models.
Methodological Strengths
- Use of both CLP and LPS models increases external validity across sepsis paradigms.
- Causal inference strengthened by ABX depletion and donor-to-recipient FMT experiments.
Limitations
- Findings are preclinical; PCN is a mouse-selective PXR agonist, limiting direct human translatability.
- Pretreatment design may not reflect real-world therapeutic timing; microbial taxa responsible remain to be defined.
Future Directions: Test human-relevant PXR agonists and YAP modulators in humanized or translational models; identify specific microbial taxa/metabolites mediating the effect; assess safety and timing in therapeutic settings.
BACKGROUND: Sepsis severity is primarily driven by exaggerated inflammatory responses that contribute to hepatic injury. The pregnane X receptor (PXR), a nuclear receptor that regulates xenobiotic and endobiotic metabolism, plays a crucial protective role against sepsis-induced liver injury and modulates hepatic regeneration. Concurrently, the gut microbiota contributes to sepsis pathogenesis via intestinal signaling and the gut-liver axis. This study aimed to evaluate how the gut microbiota mediates the protective effects exerted by the mouse PXR (mPXR) agonist pregnenolone-16α‑carbonitrile (PCN) against sepsis-induced liver injury and to elucidate the underlying mechanisms. METHODS: Sepsis was induced by cecal ligation and puncture (CLP) or lipopolysaccharide (LPS) treatment. Mice were pretreated with PCN for three consecutive days prior to model construction. Gut microbiota depletion was achieved using a cocktail of broad-spectrum antibiotics (ABX), and fecal microbiota transplantation (FMT) was performed to restore microbial communities. RESULTS: We found that depletion of gut microbiota abrogated PCN-mediated hepatoprotection in septic mice. Conversely, FMT from PCN-treated donors attenuated sepsis-induced liver injury. Furthermore, PCN-activated PXR significantly altered the gut microbiota composition in septic mice. Mechanistically, PCN treatment enhanced activation of the Yes-associated protein (YAP) signaling pathway, an effect that was diminished upon depletion of gut microbiota. Correspondingly, FMT from PCN-treated donors enhanced YAP activation and upregulated its downstream target proteins in septic mice. CONCLUSIONS: In summary, this study demonstrated that the gut microbiota mediated the protective effects of PCN against sepsis-induced liver injury by activating the YAP pathway. These findings provide novel insights into the role of gut microbiota in PXR-mediated protection during sepsis.
3. Higher promoter methylation of the Ubiquitin Associated and SH3 domain containing A (UBASH3A) gene is associated with T-lymphocyte ontogeny and reduced susceptibility to early-onset sepsis.
In a newborn cohort integrating methylation, expression, genotype, and immune phenotyping, higher UBASH3A promoter methylation at birth correlated with lower UBASH3A expression, fewer CD3+ T cells, and reduced early-onset sepsis risk. Genetic cis-meQTLs modulated baseline methylation, linking genotype to epigenetic state and infection susceptibility.
Impact: Identifies an epigenetic biomarker and mechanistic link between T-cell ontogeny and neonatal sepsis susceptibility, with genetic architecture supporting causative pathways.
Clinical Implications: UBASH3A promoter methylation could inform early risk stratification for neonatal sepsis; integrating genetic meQTL data may refine predictive models and guide surveillance.
Key Findings
- UBASH3A promoter methylation inversely correlated with gene expression and circulating CD3+ T-cell counts (r = -0.5, p < 2.2×10^-16).
- Higher promoter methylation at birth associated with reduced early-onset sepsis risk (OR = 0.26, p = 0.015).
- Baseline methylation levels were influenced by 132 cis-meQTLs (FDR < 0.05), linking genotype to epigenetic regulation.
Methodological Strengths
- Integrated multi-omics (methylation, expression, genotype) with immune cell phenotyping in a newborn cohort.
- Identification of cis-meQTLs supports genetic control over epigenetic state and associated risk.
Limitations
- Observational design limits causal inference; external validation across diverse populations is needed.
- Sample size and cohort-specific factors may affect generalizability; mechanistic pathways beyond association require functional studies.
Future Directions: Replicate findings in independent, multi-ethnic cohorts; apply causal frameworks (e.g., Mendelian randomization); perform functional assays to delineate UBASH3A’s role in neonatal immunity and infection response.
We investigated the genetic and epigenetic regulation of the UBASH3A gene and its association with early-onset sepsis. Using matched whole blood DNA methylation, gene expression, genotypes and immune cell counts from the EPIC-HIPC newborn cohort, we report promoter methylation was negatively correlated (Pearson's r = -0.5, p < 2.2×10-16) with ontogenetic changes in UBASH3A gene expression and circulating CD3+ T-cell numbers. Higher promoter methylation at birth was associated with lower UBASH3A expression and reduced early onset sepsis risk (OR = 0.26, p = 0.015). Genetic variation significantly influenced variations in baseline UBASH3A methylation (132 cis-meQTL, FDR < 0.05).