Elucidating the biological effects of cell-free DNA (cfDNA) extracted from septic mice: In Vitro and In Vivo investigations and mechanistic insights

Cell-free DNA (cfDNA) is a promising biomarker for sepsis diagnosis, treatment response tracking, and prognostication. It is known that cfDNA binds to toll-like receptors (TLRs) that can cause tissue damage and inflammatory reactions.

The objective of this study is to investigate cfDNA-activated gene expression pathways and the inflammatory and oxidative stress responses that sepsis-derived cfDNA induces in macrophages and mice. In our study, macrophages RAW 264.7 cells and healthy ICR mice were given cfDNA that had been extracted from septic mice. Gene expression levels, such as reactive oxygen species (ROS), nitric oxide (NO), and inflammatory cytokines were accessed after 24 h of delivery at different doses of cfDNA (100–400 ng/mL).

In mice administered 400 ng/mL cfDNA, TNF-α levels were significantly elevated. However, macrophages treated with cfDNA exhibited reduced cell viability alongside increased levels of ROS, NO, and catalase. In addition, granulocyte colony-stimulating factor (G-CSF), tumor necrosis factor-alpha (TNF-α), interleukin-10 (IL-10), and vascular endothelial growth factor (VEGF) were among the cytokines that were significantly increased by cfDNA at 5 ng/mL. Interestingly, genes linked to TLR signaling, oxidative stress, and chemokine pathways most notably Cxc10, Ccl5, and Ptgs1 were significantly upregulated.

Sepsis-related cfDNA strongly leads to oxidative stress and pro-inflammatory gene expression via powerful immunoredox reactions. These results emphasize the importance of conducting more research on the molecular pathways activated by cfDNA in sepsis pathophysiology.