CASP-Model Sepsis Triggers Systemic Innate Immune Responses Revealed by the Systems-Level Signaling Pathways.

Area of Science:

• Immunology
• Genomics
• Sepsis Pathophysiology

Background:

• Colon ascendens stent peritonitis (CASP) surgery can lead to polymicrobial sepsis and multi-organ failure.
• The precise mechanisms driving CASP-induced sepsis and systemic syndromes remain poorly understood.

Purpose of the Study:

• To elucidate the molecular mechanisms of CASP-model sepsis.
• To identify key regulators and signaling pathways involved in innate immune responses.
• To analyze differences in sepsis progression between wildtype and MyD88-deficient mice.

Main Methods:

• Analysis of publicly available Gene Expression Omnibus (GEO) datasets (GSE24327_A, B, C) from mouse spleens 12 hours post-CASP surgery.
• Comparative analysis of gene expression in septic MyD88-deficient mice, septic wildtype mice, and untreated wildtype mice.
• Identification and characterization of differentially expressed genes and associated signaling pathways.

Main Results:

• 21 MyD88-associated signaling pathways and key regulators (ligands, receptors, transcription factors, cytokines) were identified with significant differential expression.
• Evidence of polymicrobial sepsis (viral, bacterial, parasitic) triggered by CASP surgery was observed through coordinated gene regulation.
• Phenomena such as "systemic syndrome", "cytokine storm", and "KO MyD88 attenuation" were discussed, alongside a "spleen-mediated immune-cell infiltration" hypothesis.

Conclusions:

• The study provides systems-level insights into innate immune responses during CASP-model sepsis in wildtype and MyD88-deficient mice.
• Identified pathways and regulators serve as potential biomarkers for sepsis diagnosis and therapeutic target development.
• Findings contribute to understanding sepsis pathogenesis and may guide future research strategies for early diagnosis and prevention.