Extracellular DNA (ecDNA) activates immune cells and is involved in the pathogenesis of diseases associated with inflammation such as sepsis, rheumatoid arthritis or metabolic syndrome. DNA can be cleaved by deoxyribonucleases (DNases), some of which are secreted out of cells. The aim of this experiment was to describe plasma DNase activity in relation to extracellular DNA in adult rats, to analyse potential sex differences and to prove whether they are related to endogenous testosterone. Adult Lewis rats (n=28) of both sexes were included in the experiment. Male rats were gonadectomized or sham-operated and compared to intact female rats. Plasma ecDNA and DNase activity were measured using fluorometry and single radial enzyme diffusion assay, respectively. Concentrations of nuclear ecDNA and mitochondrial ecDNA were determined using real-time PCR. Females had 60% higher plasma DNase activity than males ( p=0.03). Gonadectomy did not affect plasma DNase in males. Neither the concentration of total ecDNA, nor nuclear or mitochondrial DNA in plasma differed between the groups. No significant correlations between DNase and ecDNA were found. From previous studies on mice, it was expected, that male rats will have higher DNase activity. In contrast, our study in rats showed the opposite sex difference. This sex difference seems not to be caused by endogenous testosterone. Interestingly, no sex differences were observed in plasma ecDNA suggesting a complex or missing association between plasma ecDNA and DNase. The observed sex difference in plasma DNase should be taken into account in animal models of ecDNA-associated diseases.

• MeSH
• Deoxyribonucleases blood   MeSH
• DNA blood   MeSH
• Rats MeSH
• Orchiectomy MeSH
• Sex Characteristics * MeSH
• Rats, Inbred Lew MeSH
• Testosterone blood   MeSH
• Animals MeSH
• Check Tag
• Rats MeSH
• Male MeSH
• Female MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• Deoxyribonucleases MeSH
• DNA MeSH
• Testosterone MeSH

Circulating extracellular DNA (ecDNA) is known to worsen the outcome of many diseases. ecDNA released from neutrophils during infection or inflammation is present in the form of neutrophil extracellular traps (NETs). It has been shown that higher ecDNA concentration occurs in a number of inflammatory diseases including inflammatory bowel disease (IBD). Enzymes such as peptidyl arginine deiminases (PADs) are crucial for NET formation. We sought to describe the dynamics of ecDNA concentrations and fragmentation, along with NETosis during a mouse model of chemically induced colitis. Plasma ecDNA concentration was highest on day seven of dextran sulfate sodium (DSS) intake and the increase was time-dependent. This increase correlated with the percentage of cells undergoing NETosis and other markers of disease activity. Relative proportion of nuclear ecDNA increased towards more severe colitis; however, absolute amount decreased. In colon explant medium, the highest concentration of ecDNA was on day three of DSS consumption. Early administration of PAD4 inhibitors did not alleviate disease activity, but lowered the ecDNA concentration. These results uncover the biological characteristics of ecDNA in IBD and support the role of ecDNA in intestinal inflammation. The therapeutic intervention aimed at NETs and/or nuclear ecDNA has yet to be fully investigated.

• Keywords
• PAD4, cell-free DNA, deoxyribonuclease activity, neutrophil extracellular traps, ulcerative colitis,
• MeSH
• Biomarkers metabolism   MeSH
• Deoxyribonucleases metabolism   MeSH
• DNA blood   metabolism   MeSH
• Endoscopy MeSH
• Extracellular Traps drug effects   metabolism   MeSH
• Extracellular Space metabolism   MeSH
• Colitis blood   chemically induced   pathology   MeSH
• DNA, Mitochondrial blood   MeSH
• Mice, Inbred C57BL MeSH
• Mice MeSH
• Ornithine analogs & derivatives   pharmacology   MeSH
• Protein-Arginine Deiminase Type 4 metabolism   MeSH
• Dextran Sulfate MeSH
• Streptonigrin pharmacology   MeSH
• Intestines drug effects   pathology   MeSH
• Intestinal Mucosa drug effects   pathology   MeSH
• Severity of Illness Index MeSH
• Inflammation blood   pathology   MeSH
• Animals MeSH
• Check Tag
• Mice MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• Biomarkers MeSH
• Deoxyribonucleases MeSH
• DNA MeSH
• DNA, Mitochondrial MeSH
• N-alpha-benzoyl-N5-(2-chloro-1-iminoethyl)-L-ornithine amide MeSH Browser
• Ornithine MeSH
• Protein-Arginine Deiminase Type 4 MeSH
• peptidylarginine deiminase 4, mouse MeSH Browser
• Dextran Sulfate MeSH
• Streptonigrin MeSH