Daily Sepsis Research Analysis
Three impactful sepsis papers span pathophysiology, diagnostics, and prevention. A mechanistic study identifies Nogo-B as a suppressor of macrophage efferocytosis that worsens organ injury in sepsis. A MOF-encapsulated, PAM-relaxed CRISPR-Cas12a enables broad-spectrum detection of sepsis-causing bacteria at low copy numbers, while a national cohort links adolescent obesity and low fitness to higher adult sepsis risk.
Summary
Three impactful sepsis papers span pathophysiology, diagnostics, and prevention. A mechanistic study identifies Nogo-B as a suppressor of macrophage efferocytosis that worsens organ injury in sepsis. A MOF-encapsulated, PAM-relaxed CRISPR-Cas12a enables broad-spectrum detection of sepsis-causing bacteria at low copy numbers, while a national cohort links adolescent obesity and low fitness to higher adult sepsis risk.
Research Themes
- Macrophage efferocytosis and organ injury in sepsis
- Broad-spectrum CRISPR-based diagnostics for bacterial sepsis
- Lifecourse prevention: adolescent BMI/fitness and adult sepsis risk
Selected Articles
1. Nogo-B impairs efferocytosis in monocyte-derived macrophages and exacerbates septic liver injury.
Septic conditions upregulate Nogo-B in monocytes and monocyte-derived macrophages, impairing efferocytosis through OXPHOS suppression and HIF-1α/ADAM17 signaling. Myeloid-specific Nogo deletion improved efferocytosis and mitigated liver and lung injury, positioning Nogo-B as a promising target to restore efferocytosis in sepsis.
Impact: Reveals a previously unrecognized regulator of efferocytosis that directly links mitochondrial metabolism to inflammatory organ injury in sepsis. Offers a mechanistically grounded therapeutic target.
Clinical Implications: If translated, Nogo-B inhibition could restore efferocytosis and reduce sepsis-related liver and lung injury, complementing antimicrobial and organ support strategies.
Key Findings
- Septic conditions increased Nogo-B expression and impaired efferocytosis in monocytes and monocyte-derived macrophages but not in peritoneal macrophages or Kupffer cells.
- Nogo-B impaired efferocytosis via suppression of oxidative phosphorylation (OXPHOS) and activation of HIF-1α/ADAM17 signaling.
- Myeloid-specific Nogo deletion improved efferocytosis and attenuated septic liver and lung injury.
Methodological Strengths
- Use of myeloid-specific genetic deletion to establish causality.
- Multi-modal mechanistic interrogation (metabolism, mitochondrial calcium, HIF-1α/ADAM17 signaling).
Limitations
- Preclinical models predominate; human validation is limited.
- Incomplete reporting of sample sizes and therapeutic modulation outcomes within the abstract.
Future Directions: Validate Nogo-B as a biomarker and therapeutic target in human sepsis cohorts; assess pharmacologic inhibitors’ efficacy and safety; define cell-type specificity across tissues.
BACKGROUND & AIMS: Efferocytosis is essential for maintaining tissue homeostasis and resolving inflammation, but this process is compromised during sepsis. This study aimed to elucidate the role of neurite outgrowth inhibitor protein B (Nogo-B) in regulating macrophage efferocytosis under septic conditions and to evaluate its potential as a therapeutic target. METHODS: We evaluated Nogo-B expression and efferocytosis in monocytes and monocyte-derived macrophages (MDMs) under septic conditions. Myeloid-specific Nogo deletion was used to assess its impact on MDM efferocytosis and septic organ injury. Mechanistic studies examined HIF-1α/ADAM17 signaling, mitochondrial calcium dynamics, metabolic activity, and endoplasmic reticulum (ER) stress. INCB081776, a dual MerTK/AXL inhibitor, was administered RESULTS: Septic conditions upregulated Nogo-B expression and impaired efferocytosis in monocytes and MDMs, but not in peritoneal macrophages or Kupffer cells (n = 3-7, CONCLUSIONS: Nogo-B impairs MDM efferocytosis by suppressing OXPHOS and activating HIF-1α/ADAM17 signaling, thereby exacerbating septic liver and lung injury. Targeting Nogo-B offers a novel strategy to restore efferocytosis and alleviate sepsis. IMPACT AND IMPLICATIONS: Efferocytosis is compromised during sepsis, contributing to enhanced inflammation and organ damage. Our study identified Nogo-B as a critical mediator linking disrupted mitochondrial calcium uptake to impaired MDM efferocytosis. Targeting Nogo-B may represent a novel therapeutic strategy to restore efferocytosis and attenuate sepsis-related tissue injury. Further translational studies are needed to validate these findings in human disease.
2. CRISPR in MOF Formulation with Enhanced Stability, Activity, and Altered PAM Specificity for Broad-Spectrum Diagnosis of Bacterial Sepsis.
CRISPR-FLEXMO combines a PAM-relaxed Cas12a (K607R) with Mn-MOF encapsulation to enable robust, broad-spectrum detection of Gram-positive and Gram-negative sepsis pathogens. It targets a conserved TTCC PAM near the Shine-Dalgarno region and achieves a detection limit around 10 CFU/mL with enhanced stability under stress.
Impact: Addresses two critical bottlenecks in CRISPR diagnostics—PAM constraints and enzyme stability—enabling single-primer broad-spectrum pathogen detection relevant to time-critical sepsis care.
Clinical Implications: If clinically validated, this platform could shorten time-to-pathogen identification across diverse bacteria, guiding early targeted therapy and antimicrobial stewardship in sepsis.
Key Findings
- A PAM-relaxed Cas12a variant (K607R) exhibits enhanced cis/trans-cleavage activity.
- Mn-MOF encapsulation preserves CRISPR enzyme functionality under ambient, thermal, and chaotropic stress conditions.
- Universal targeting of a TTCC PAM in conserved 16S rRNA upstream regions enables broad-spectrum detection with a single primer pair.
- Analytical sensitivity reaches approximately 10 CFU/mL.
Methodological Strengths
- Rational enzyme engineering coupled with materials science (MOF encapsulation) to improve diagnostic robustness.
- Design of universal primers targeting a conserved genomic region to broaden pathogen coverage.
Limitations
- Clinical validation on patient samples and real-world workflows is not reported in the abstract.
- Potential challenges include sample preparation, host background interference, and contamination control in point-of-care settings.
Future Directions: Prospective clinical studies comparing against culture and PCR; integration into rapid sample-to-answer devices; assessment of multiplexing and antimicrobial resistance gene detection.
Sepsis is a life-threatening condition caused by polymicrobial infections and remains a global health emergency that requires rapid and broad-spectrum diagnostics. Existing CRISPR-based assays face two major limitations that restrict their application for sepsis: narrow protospacer adjacent motif (PAM) site compatibility and poor enzyme stability under clinical and environmental stresses. A modular diagnostic platform is presented, CRISPR-FLEXMO (CRISPR with flexible PAM in metal-organic framework encapsulation, MOF), which integrates a PAM-relaxed Cas12a variant (K607R) with a manganese-coordinated MOF (Mn-MOF) for stable and specific detection of sepsis-causing bacteria. The system targets a conserved region upstream of the Shine-Dalgarno sequence in the 16S rRNA gene containing a universal TTCC PAM, enabling broad-spectrum detection with a single universal primer pair across Gram-negative and Gram-positive pathogens. The K607R variant shows enhanced cis- and trans-cleavage activity, while Mn-MOF encapsulation maintains enzyme functionality under ambient, thermal, and chaotropic stress. The assay detects as low as 10 CFU mL
3. High BMI and low cardiorespiratory fitness in adolescence are associated with increased risk of severe bacterial infections in adulthood.
In a national cohort of nearly one million Swedish adolescents followed for about three decades, higher BMI and lower cardiorespiratory fitness at age 18 were associated with increased risks of adult bacterial pneumonia, sepsis, and infective endocarditis. Obesity conferred a threefold sepsis risk, with elevated hazards beginning at high-normal BMI.
Impact: Establishes adolescent fitness and adiposity as modifiable risk factors for adult sepsis, expanding prevention beyond acute care. The very large sample and long follow-up strengthen inference.
Clinical Implications: Supports population-level strategies to improve adolescent fitness and reduce obesity as part of long-term sepsis prevention; informs risk stratification in adult care by incorporating lifecourse factors.
Key Findings
- Obesity in late adolescence was associated with a threefold increased risk of adult sepsis (HR ~3.1, 95% CI 2.7–3.5).
- Elevated infection risk was detectable already at high-normal BMI (22.5–25 kg/m²).
- Low adolescent cardiorespiratory fitness independently increased risks of severe bacterial infections and related mortality.
Methodological Strengths
- Nationwide, registry-based cohort with nearly one million participants and decades of follow-up.
- Objective measurements of BMI and fitness at baseline; hard clinical outcomes captured via registers.
Limitations
- Generalizability may be limited by conscript population characteristics (e.g., sex distribution, health selection).
- Observational design with potential residual confounding despite large sample size.
Future Directions: Intervention trials to improve adolescent fitness and reduce obesity with infection endpoints; causal inference via Mendelian randomization; elucidation of immunometabolic mechanisms linking adiposity/fitness to sepsis.
BACKGROUND: Obesity and poor physical fitness in youth are established risk factors for future cardiovascular disease and cancer. However, their potential impact on the risk of severe bacterial infections later in life remains unclear. METHODS: This register-based cohort study followed almost 1 million Swedish conscripts (mean age 18.3 years) over a period of three decades. Measured body mass index (BMI) and cardiorespiratory fitness (CRF) at conscription to military service served as exposure variables, whereas outcomes included morbidity and mortality attributed to bacterial pneumonia, sepsis, and infective endocarditis. RESULTS: High BMI and low CRF in late adolescence were strongly associated with an increased risk of bacterial pneumonia, sepsis, and infective endocarditis in adulthood. The highest risk was seen among the obese for sepsis (hazard ratio [HR] 3.1 (2.7-3.5)), with elevated hazards observed already at high-normal BMI levels (22.5-25 kg/m CONCLUSION: High BMI and low CRF in adolescence are associated with an increased risk of contracting and dying of severe bacterial infections later in life. Hence, addressing these preventable risk factors in youths may serve as an effective measure to improve their long-term health.