Daily Sepsis Research Analysis
Analyzed 11 papers and selected 3 impactful papers.
Summary
Two mechanistic studies identify actionable immune regulators in sepsis—an RPSA-OLFM4 migratory checkpoint in neutrophils and CHD1 as an NF-κB-amplifying chromatin remodeler in macrophages—while a large GBD-based analysis maps shifting maternal sepsis burdens and widening health inequities in LMICs. Together, these works span bench-to-population insights pointing to novel targets and policy priorities.
Research Themes
- Immune cell trafficking checkpoints in sepsis
- Chromatin-mediated amplification of inflammatory signaling
- Global health inequalities in maternal sepsis
Selected Articles
1. RPSA-OLFM4 axis governs neutrophil migration against bacterial infection and sepsis.
Using myeloid-specific knockout mice, patient neutrophils, and in vivo therapeutic modulation, this study identifies an RPSA-OLFM4 checkpoint that enables neutrophil migration by sustaining RhoA/ROCK1/pMLC2 signaling and MYH9 localization. Targeting this axis restored migration and improved outcomes in infected and septic mice, positioning it as a tractable host-defense strategy.
Impact: Reveals a previously unrecognized migratory checkpoint with mechanistic depth and translational relevance, offering a novel immunomodulatory target in sepsis.
Clinical Implications: Although preclinical, modulating the RPSA-OLFM4 axis could augment neutrophil trafficking and bacterial clearance in sepsis; patient biomarker development (RPSA/OLFM4) may enable risk stratification for impaired neutrophil migration.
Key Findings
- Myeloid-specific Rpsa deletion reduced neutrophil infiltration and worsened Streptococcus suis serotype 2 infection.
- RPSA deficiency upregulated OLFM4, inhibited RhoA/ROCK1/pMLC2 signaling, reduced MYH9, and mislocalized MYH9 from uropods, disrupting migration.
- Neutrophils from septic patients showed decreased RPSA and increased OLFM4 associated with impaired migratory capacity.
- Therapeutic targeting of the RPSA-OLFM4 axis restored neutrophil migration and improved outcomes in infected and septic mice.
Methodological Strengths
- Use of myeloid-specific knockout, adoptive transfer, and neutrophil depletion to establish cell-intrinsic function
- Mechanistic dissection across signaling (RhoA/ROCK1/pMLC2) and cytoskeletal effectors (MYH9)
- Translational validation in human septic neutrophils and in vivo therapeutic proof-of-concept
Limitations
- Preclinical models centered on S. suis may limit pathogen generalizability
- Human data are observational without interventional validation
- Potential species-specific differences in neutrophil regulation
Future Directions: Test RPSA-OLFM4 modulation across diverse pathogens, develop clinical-grade assays for RPSA/OLFM4, and evaluate safety/efficacy in early-phase sepsis trials.
Neutrophil migration to bacterial infection sites is key for host defense. Host ribosomal protein SA (RPSA) has been recently reported to regulate the anti-infection immunity of immune cells; however, its role in neutrophil migration remains unclear. Here, using myeloid-specific Rpsa-deficient mice, we found that RPSA deletion inhibited neutrophil infiltration and markedly exacerbated Streptococcus suis serotype 2 infection. Adoptive cell transfer and neutrophil depletion assays identified RPSA as vital for the anti-infective function of neutrophils. Mechanistically, RPSA deficiency induced the overexpression of olfactomedin 4 (OLFM4), which in turn inhibited the activation of the RhoA/ROCK1/pMLC2 signaling pathway, reduced MYH9 expression, and caused aberrant MYH9 translocation from the uropod to the cytosol in migrating neutrophils. Ultimately, this disrupted cytoskeletal polarization and uropod extension, thereby abrogating migratory function. Clinically, septic patients' neutrophils exhibited reduced RPSA and elevated OLFM4 expression, a phenotype that correlated with a marked impairment of migratory capacity. Therapeutic targeting of the RPSA-OLFM4 axis restored neutrophil migration and improved disease outcomes in both S. suis 2-infected and septic mice. Thus, our findings demonstrate that RPSA promotes neutrophil migration via downregulating OLFM4 to counter bacterial infection, and establish the RPSA-OLFM4 axis as a critical immune migratory checkpoint in host antibacterial immunity.
2. CHD1 regulates the inflammatory response in macrophages and functions as a pharmacological target during sepsis.
CHD1 is induced via TLR4/MyD88 in macrophages and enhances NF-κB-dependent inflammatory transcription; its pharmacologic inhibition improves survival and organ injury in septic mice and correlates with severity in patient datasets. These data nominate CHD1 as a prognostic and therapeutic target for early sepsis.
Impact: Uncovers a previously unrecognized chromatin regulator of macrophage activation with both mechanistic clarity and therapeutic tractability in sepsis models.
Clinical Implications: If validated clinically, CHD1 inhibition could temper early hyperinflammation in sepsis. Blood CHD1 expression may aid early risk stratification and patient selection for anti-inflammatory interventions.
Key Findings
- CHD1 is induced in macrophages by LPS via the TLR4/MyD88 pathway and interacts with NF-κB to amplify pro-inflammatory cytokine production.
- Early pharmacological inhibition of CHD1 improved survival and reduced multi-organ injury in LPS-induced septic mice.
- Elevated blood CHD1 expression in early sepsis correlates with disease severity and poor prognosis in patient transcriptomic datasets.
Methodological Strengths
- Integrated bioinformatics with experimental validation across cellular and in vivo models
- Therapeutic proof-of-concept using pharmacological inhibition in a sepsis model
- Clinical relevance supported by analysis of patient transcriptomic datasets
Limitations
- Relies on an LPS-induced sepsis model which may not capture all clinical phenotypes
- Lack of human interventional data to confirm targetability and safety
- Potential context-specificity of CHD1’s role across tissues and pathogens
Future Directions: Validate CHD1 as a biomarker in prospective cohorts, define safety/PK-PD of inhibitors, and test combination strategies with antibiotics or organ support in translational models.
Inflammation is a defining feature of sepsis and a major determinant of disease progression, organ dysfunction, and mortality. Excessive inflammatory responses during the early stage not only cause direct tissue injury but also shape subsequent immune suppression. Macrophages are central orchestrators of this early immune response; however, the molecular regulators that govern macrophage activation in sepsis remain incompletely understood. In this study, integrated bioinformatic analyses of lipopolysaccharide (LPS)-stimulated macrophages combined with experimental validation were performed to identify key regulatory factors and elucidate the underlying mechanisms driving inflammatory responses. An LPS-induced mouse model of sepsis was used to evaluate the therapeutic potential of pharmacological key factor inhibition. In addition, public transcriptomic datasets from sepsis patients were analyzed to assess the clinical relevance of its expression. The results demonstrated that CHD1 was identified as a previously unrecognized regulator of macrophage-driven inflammation in sepsis. CHD1 expression was induced in macrophages following LPS stimulation through the TLR4/MyD88 signaling axis. Mechanistically, CHD1 amplified pro-inflammatory cytokine production by interacting with NF-κB. Early pharmacological inhibition of CHD1 markedly improved survival and alleviated multi-organ injury in septic mice. Furthermore, analysis of clinical transcriptome datasets revealed that elevated blood CHD1 expression in early sepsis was associated with disease severity and poor prognosis. Collectively, this study identifies macrophage-derived CHD1 as a critical driver of inflammation in sepsis by selectively enhancing NF-κB-dependent inflammatory transcription. Targeting CHD1 represents a promising strategy for early intervention in sepsis and may provide both prognostic and therapeutic value.
3. Disease burden of maternal sepsis and maternal infections in low- and middle-income countries from 1990 to 2023 and projections to 2035: An analysis based on the global burden of disease study.
In 129 LMICs, maternal sepsis/infections showed declining rates (e.g., DALYs rate EAPC −3.11) but increasing absolute incident and prevalent cases. Burdens worsened in low-income countries (driven by population growth) and inequalities widened, while projections suggest continued mortality declines but minimal incidence reductions.
Impact: Provides comprehensive, policy-relevant mapping of maternal sepsis burden and inequalities across LMICs over three decades with future projections, guiding targeted interventions.
Clinical Implications: Supports prioritizing resources to low-income settings, integrating equity metrics into monitoring, and strengthening prevention and obstetric infection control to curb rising absolute cases.
Key Findings
- DALYs rate declined markedly from 1990–2023 (EAPC −3.11, 95% CI −3.26 to −2.95).
- Absolute incident and prevalent cases increased by 24% and 33%, while deaths and DALYs decreased by 37% and 39%.
- Burden worsened in low-income countries (incident +126%, prevalent +109%), while upper-middle-income countries saw large decreases in deaths (−83%) and DALYs (−81%).
- Health inequalities widened (DALYs concentration index from −0.392 to −0.594; mortality from −0.395 to −0.603).
- ARIMA projections: mortality continues to decline (average −6.4%/year, 2024–2035); incidence reduction limited (−0.82%/year).
Methodological Strengths
- Use of GBD 2023 data across 129 LMICs with standardized metrics
- Joinpoint regression, decomposition, and inequality analyses to identify trends and drivers
- ARIMA forecasting to project future burden trajectories
Limitations
- Dependent on modeled estimates and data quality heterogeneity inherent to GBD sources
- Ecological analysis limits causal inference and within-country granularity
- Potential variability in maternal sepsis definitions and coding over time
Future Directions: Link country-level trends to intervention coverage data, strengthen primary data systems in low-income settings, and evaluate equity-oriented packages to reduce absolute incidence.
BACKGROUND: Maternal sepsis and maternal infections (MSMI) are significant causes of maternal mortality in low- and middle-income countries (LMICs). This study, leveraging data from the Global Burden of Disease Study 2023 (GBD 2023), intended to evaluate the trends in the disease burden of MSMI in LMICs from 1990 to 2023, along with its inequality characteristics and future trends. METHODS: Based on the GBD 2023 database, data on the incidence, prevalence, mortality, and disability-adjusted life years (DALYs) rates of MSMI in 129 LMICs from 1990 to 2023 were extracted. Joinpoint regression, decomposition analysis, and health inequality analysis were employed to evaluate changes in disease burden and their driving factors. An autoregressive integrated moving average (ARIMA) model was established to predict trends in disease burden from 2024 to 2035. RESULTS: From 1990 to 2023, the relative burden of MSMI in LMICs generally declined, and the most pronounced decrease was observed in the DALYs rate (estimated annual percentage change (estimated annual percentage change (EAPC) = -3.11, 95% confidence interval (CI): -3.26 to -2.95). However, the absolute burden showed a divergent trend. Specifically, the number of incident cases and prevalent cases increased by 24% and 33%, respectively, while the number of deaths and DALYs decreased by 37% and 39%, respectively. Stratified analysis uncovered that the burden worsened in low-income (gross national income (GNI)-L) countries (with incident cases and prevalent cases rising by 126% and 109%, respectively), whereas decreases were more significant in upper-middle-income (GNI-UM) countries (with deaths and DALYs decreasing by 83% and 81%, respectively). The increased burden in GNI-L countries was primarily driven by population growth, with relative contributions to the incidence burden and prevalence burden of 121.6% and 136.5%, respectively. In addition, widening health inequalities were observed. The concentration indexes for the DALYs rate and mortality rate decreased from -0.392 to -0.594 and from -0.395 to -0.603, respectively. ARIMA projections indicated that while the mortality rate was expected to continue to decline from 2024 to 2035 (with an average annual decrease of -6.4%), the decrease in the incidence rate was projected to be limited (with an average annual decrease of -0.82%). CONCLUSION: Over the past three decades, while the overall burden of MSMI in LMICs has decreased, the control of its absolute burden remains insufficient. GNI-L countries continue to bear a higher burden and experience widening health inequalities. Future prevention and control efforts should not only focus on continuously reducing the overall burden but also prioritize targeted resource allocation for GNI-L countries. Moreover, equity should be integrated into routine monitoring and evaluation systems.