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Updated: Apr 5, 2026
Evaluation of a Reliable Biomarker in a Cecal Ligation and Puncture-Induced Mouse Model of Sepsis
Published on: December 9, 2022
Origin of Circulating Free DNA in Sepsis: Analysis of the CLP Mouse Model
Shigeto Hamaguchi1, Yukihiro Akeda2, Norihisa Yamamoto1
1Division of Infection Control and Prevention, Osaka University Graduate School of Medicine, Osaka 565-0871, Japan ; International Research Center for Infectious Diseases, Research Institute for Microbial Diseases, Osaka University, Osaka 565-0871, Japan.
Abstract:
Recently, it has been reported that circulating free DNA (cf-DNA) in the blood is increased in various infectious diseases, including sepsis. Moreover, a relationship between cf-DNA and neutrophil extracellular traps (NETs) has been suggested. However, it is still unclear what the source and physiological role of cf-DNA in sepsis are. In this study, we examined the source of cf-DNA by detecting citrullinated histone H3, a characteristic feature of NET formation, in cecal ligation and puncture- (CLP-)operated mice. In addition, neutrophil depletion using anti-Ly6G antibodies was performed to assess the association between neutrophils and cf-DNA. Increased cf-DNA levels were observed only in CLP mice and not in the control groups; the qPCR findings revealed that the cf-DNA was mainly host-derived, even in bacteremic conditions. Citrullinated histone H3 was not increased in the neutrophils upon CLP, and the depletion of neutrophils showed limited effects on decreasing the amount of cf-DNA. Taken together, these results suggested that elevated cf-DNA levels during early-phase sepsis may represent a candidate biomarker for the severity of sepsis and that, contrary to previous findings, cf-DNA is not derived from neutrophils or NETs.
Insights
Elevated circulating free DNA (cf-DNA) in early sepsis is host-derived, not from neutrophils or neutrophil extracellular traps (NETs), suggesting cf-DNA may serve as a sepsis severity biomarker.
Area of Science:
- Molecular Biology
- Immunology
- Pathophysiology
Background:
- Circulating free DNA (cf-DNA) levels rise in sepsis.
- A link between cf-DNA and neutrophil extracellular traps (NETs) has been proposed.
- The precise source and function of cf-DNA in sepsis remain unclear.
Purpose of the Study:
- To investigate the origin of cf-DNA during sepsis.
- To determine the role of neutrophils and NETs in cf-DNA generation in sepsis.
- To evaluate cf-DNA as a potential sepsis biomarker.
Main Methods:
- Cecal ligation and puncture (CLP) model in mice to induce sepsis.
- Detection of citrullinated histone H3 as a NET marker.
- Neutrophil depletion using anti-Ly6G antibodies.
- Quantitative PCR (qPCR) to analyze cf-DNA origin.
Main Results:
- cf-DNA significantly increased only in CLP-induced sepsis mice.
- qPCR confirmed cf-DNA was predominantly host-derived, even with bacteremia.
- Citrullinated histone H3 did not increase in neutrophils post-CLP.
- Neutrophil depletion had minimal impact on cf-DNA levels.
Conclusions:
- Elevated cf-DNA in early sepsis is likely host-derived and not from neutrophils or NETs.
- Contrary to prior research, neutrophils and NETs are not the primary source of cf-DNA in this sepsis model.
- Increased cf-DNA may serve as a valuable biomarker for sepsis severity.
