Daily Sepsis Research Analysis
Analyzed 28 papers and selected 3 impactful papers.
Summary
Three impactful sepsis papers stood out today: a mechanistic study identifies a DAPK2–HSPA5–IRE1α pathway driving macrophage endoplasmic reticulum stress in sepsis; an integrative translational study supports a protective role of MMP-9 in sepsis-induced lung injury via fibrinogen-driven inflammation; and a multicentre cohort challenges the 14-day antifungal standard by showing no disadvantage to 7–13 days in uncomplicated candidaemia.
Research Themes
- Macrophage ER stress signaling (DAPK2–HSPA5–IRE1α) in sepsis pathophysiology
- Coagulation–inflammation crosstalk and MMP-9 as a protective mediator/biomarker in sepsis-induced lung injury
- Antimicrobial stewardship: optimizing antifungal duration for uncomplicated candidaemia
Selected Articles
1. Death-associated protein kinase 2 (DAPK2) propagates endoplasmic reticulum stress in macrophages to worsen sepsis through HSPA5-IRE1α axis.
Macrophage DAPK2 is upregulated in sepsis via TLR4–MyD88–NF-κB and drives ER stress by phosphorylating HSPA5 at Ser588, promoting its degradation and activating IRE1α. Genetic deletion of DAPK2 in macrophages ameliorated sepsis and ER stress, and pathway perturbations confirmed causality, positioning the DAPK2–HSPA5–IRE1α axis as a therapeutic target.
Impact: It uncovers a previously unrecognized kinase–chaperone mechanism linking innate immune signaling to ER stress and organ injury in sepsis, revealing a druggable axis.
Clinical Implications: Pharmacologic inhibition of DAPK2 or stabilization of HSPA5/attenuation of IRE1α signaling could mitigate macrophage ER stress and improve sepsis outcomes; DAPK2 expression may serve as a stratification biomarker.
Key Findings
- DAPK2 is elevated in sepsis macrophages and transcriptionally induced via TLR4–MyD88–NF-κB signaling.
- Macrophage-specific DAPK2 deletion reduces sepsis severity and the ER stress response in mice.
- DAPK2 binds HSPA5 and phosphorylates it at Ser588, promoting proteasomal degradation and IRE1α activation.
- Inhibiting HSPA5 worsens sepsis in DAPK2-deficient mice, an effect reversed by IRE1α deactivation.
Methodological Strengths
- Multi-layer mechanistic validation (genetic deletion, LC-MS/MS interactome, site-specific phosphorylation, pathway rescue).
- Use of patient-derived and murine macrophages to support translational relevance.
Limitations
- Preclinical study without interventional validation in humans.
- Quantitative sample sizes for individual experiments are not detailed in the abstract.
Future Directions: Evaluate DAPK2 inhibitors or HSPA5/IRE1α modulators in diverse sepsis models; assess DAPK2–HSPA5 signaling as a biomarker in clinical cohorts.
Sepsis is associated with a pronounced but poorly understood endoplasmic reticulum stress (ERS) response. In this study, we found that death-associated protein kinase 2 (DAPK2), a calcium/calmodulin-regulated serine/threonine kinase, exhibits elevated expression in macrophages from patients with sepsis and from septic mice. Macrophage DAPK2 expression is transcriptionally upregulated through the activation of the Toll-like receptor 4 (TLR4)-myeloid differentiation primary response 88 (MyD88)-nuclear factor-κB (NF-κB) pathway. Macrophage-specific deletion of DAPK2 attenuated sepsis severity and mitigated the ERS response. Using liquid chromatography-tandem mass spectrometry (LC-MS/MS), we identified heat shock protein family A member 5 (HSPA5) as a binding partner for DAPK2. Because DAPK2 function had been previously associated with the kinase activity, we speculated that it might control ERS of macrophages through HSPA5 phosphorylation. Further investigation indeed revealed that DAPK2 phosphorylates HSPA5 at serine-588, which promotes the proteasomal degradation of HSPA5 and subsequently leads to the activation of inositol-requiring enzyme 1α (IRE1α). Inhibition of HSPA5 exacerbated sepsis in mice with macrophage-specific DAPK2 deficiency; however, this effect was abrogated by the deactivation of IRE1α. In conclusion, our findings demonstrate that DAPK2 propagates macrophage ERS through the HSPA5-IRE1α axis during systemic infection, suggesting this pathway as a potential therapeutic target in sepsis.
2. Targeting inflammation and coagulation: MMP-9 deficiency exacerbates sepsis induced acute lung injury through fibrinogen-driven inflammation.
Integrative analyses (human RNA-seq, murine ALI, PPI, and Mendelian randomization) identified MMP-9 as a causally protective factor in sepsis-induced lung injury. Computational modeling supported an interaction with fibrinogen, and in vivo CLP experiments demonstrated that MMP-9 deficiency exacerbates lung injury, highlighting MMP-9 as a potential biomarker and therapeutic node at the coagulation–inflammation interface.
Impact: Combining human genomics with causal inference and animal validation advances mechanistic understanding and nominates MMP-9 for early diagnosis and pathway-targeted interventions in sepsis-related lung injury.
Clinical Implications: If validated clinically, circulating MMP-9 could aid early risk stratification in sepsis-induced lung injury and inform therapies modulating fibrin(ogen)–inflammation pathways.
Key Findings
- Cross-species integrative analysis identified MMP-9 among coagulation-related sepsis DEGs and Mendelian randomization supported a causal protective role.
- Molecular docking and 100-ns molecular dynamics suggested a biologically plausible interaction between MMP-9 and fibrinogen.
- In vivo CLP models showed that MMP-9 deficiency worsens lung injury, supporting a protective role for MMP-9 in SALI.
- Translational potential was proposed for MMP-9 as an early diagnostic biomarker integrating coagulation–inflammation crosstalk.
Methodological Strengths
- Integrative multi-omic and computational pipeline (RNA-seq, PPI, MR, docking, MD simulation) with in vivo validation.
- Use of causal inference (Mendelian randomization) to prioritize targets beyond correlation.
Limitations
- Preclinical findings require external clinical validation in independent sepsis cohorts.
- Mendelian randomization assumptions may be violated by pleiotropy; functional quantitation in humans is pending.
Future Directions: Validate circulating MMP-9 as a biomarker in prospective sepsis cohorts; test fibrinogen–MMP-9 pathway modulation in translational models and early-phase trials.
Sepsis is caused by a dysregulated host response to infection, characterized by multiorgan failure in which the lung is the primary target. Although matrix metalloproteinase-9 (MMP9), a macrophage-derived protease, is known to degrade extracellular matrix proteins during inflammation, its specific role in sepsis-induced lung injury (SALI) remains to be elucidated. This study elucidates the protective function of MMP9 in SALI and validated its translational potential as an early diagnostic biomarker that integrates coagulation-inflammation crosstalk. First, we integrated human blood bulk RNA-seq data and an in-house LPS-induced murine ALI model to extract coagulation-related sepsis DEGs (Cos-Gs), constructed a PPI network, and applied two-sample Mendelian randomization (MR), which identified MMP9 as a causal protection gene. Additionally, we performed molecular docking using the ZDOCK server and 100 ns molecular dynamics simulations with Gromacs to explore the interaction between MMP9 and fibrinogen. Next, in vivo studies using CLP-operated MMP9
3. Re-evaluating the 14-day rule: short-course antifungal therapy for uncomplicated candidaemia in a multicentre cohort study.
In 203 adults with uncomplicated candidaemia achieving clearance and source control, 7–13 days of antifungals did not increase 14-day post-EOT mortality or 90-day recurrence compared with 14–20 days, after IPTW adjustment. Findings were consistent across multivariable and subgroup analyses.
Impact: This challenges the entrenched 14-day rule and supports shorter antifungal courses in carefully selected uncomplicated candidaemia, with potential benefits in toxicity, cost, and stewardship.
Clinical Implications: Clinicians may consider 7–13 days of antifungals for uncomplicated candidaemia after clearance and source control, while awaiting prospective validation and excluding complicated foci.
Key Findings
- Among 203 patients, short-course therapy (7–13 days) showed similar EOT 14-day mortality to long-course therapy (5.6% vs 8.4%).
- Short-course therapy was not associated with increased 90-day recurrence after EOT (overall recurrence 4.4%).
- Results were consistent across crude, multivariable, IPTW-weighted analyses, Kaplan–Meier, and subgroup analyses.
- Secondary outcomes (EOT 90-day mortality, EOT 1-year recurrence) did not differ between groups.
Methodological Strengths
- Multicentre cohort with clearly defined ‘uncomplicated’ candidaemia and IPTW to address confounding.
- Multiple sensitivity and subgroup analyses supporting robustness.
Limitations
- Retrospective design with potential residual confounding and selection bias.
- Modest sample size and limited generalizability to complicated or disseminated infections.
Future Directions: Prospective, randomized trials to confirm non-inferiority of short-course regimens and to identify patient subgroups most suitable for abbreviated therapy.
OBJECTIVES: Current guidelines recommend at least 14 days of antifungal therapy for uncomplicated candidaemia after blood culture clearance, despite limited supporting evidence. We evaluated whether antifungal treatment duration was associated with clinical outcomes. METHODS: This multicentre retrospective study in Taiwan (January 2014 to June 2024) included adults with uncomplicated candidaemia (microbiological clearance within 5 days, adequate source control, and no deep-seated or metastatic infection) completing 7-20 days of antifungal therapy. Patients were classified into short-course (7-13 days) and long-course (14-20 days) groups. Primary outcomes were all-cause mortality within 14 days and recurrence within 90 days after the end of treatment (EOT) and secondary outcomes were EOT 90-day mortality and EOT 1-year recurrence. Inverse probability of treatment weighting (IPTW) was applied to adjust for confounders. RESULTS: Among 203 patients, 72 (35.5%) received short-course and 131 (64.5%) long-course therapy. Overall, EOT 14-day mortality was 7.4% (5.6% versus 8.4% in short-course and long-course groups, respectively). Short-course therapy was not associated with increased EOT 14-day mortality in crude (OR 0.64, 95% CI 0.17-1.95), multivariable (aOR 0.33, 95% CI 0.06-1.35), or IPTW-weighted analyses (aOR 0.42, 95% CI 0.11-1.55). The EOT 90-day recurrence rate was 4.4%, with no significant differences across analyses. IPTW-weighted Kaplan-Meier and subgroup analyses showed consistent findings. No significant differences were observed in secondary outcomes, including EOT 90-day mortality and EOT 1-year recurrence. CONCLUSIONS: Short-course antifungal therapy was not associated with increased mortality or recurrence compared with long-course therapy among patients with uncomplicated candidaemia who achieved adequate source control and microbiological clearance.