Main author: Jon Johannes Jonsson
Institution or Company: Dept. of Biochemistry and Molecular Biology, University of Iceland, Dept. of Genetics and Molecular Medicine, Landspitali
Co-Authors, Institution or Company:
Bjarki Gudmundsson, Dept. of Biochemistry and Molecular Biology, University of Iceland, Dept. of Genetics and Molecular Medicine, Landspitali. Hans G. Thormar, Dept. of Biochemistry and Molecular Biology, University of Iceland, Lifeind ehf., Reykjavik, Iceland. Elsa Jonsdottir (presenter), Faculty of Medicine, University of Iceland. Hrodmar Helgason, Faculty of Medicine, University of Iceland. Kristinn Sigvaldason, Dept. of Anesthesiology and Intensive Care, Landspitali. Helgi Oskarsson, Dept. of Biochemistry and Molecular Biology, University of Iceland. Helgi Sigurdsson, Dept. of Oncology, Landspitali.is.
Introduction: The Northern Lights Assay (NLA) can detect various types of damage including single-stranded breaks, double-stranded breaks, intrastrand and interstrand DNA crosslinks (ICL), single-stranded DNA and bulky lesions in cfDNA in body fluids.
Methods: Body fluids samples have been tested from healthy subjects of various age and both sexes and patients with diseases where damage to cfDNA might be expected. DNA was isolated with gentle methods avoiding denaturation of DNA induced with chaotropic agents. Purified samples were subjected to NLA in microgels. In selected cases DNA was pretreated with fpg enzyme to detect oxidative lesions as nicks.
Results: We tested NLA on DNA isolated from whole blood, plasma, saliva, urine sediment and cell-free urine. cfDNA samples from each body fluid showed patterns that were variable between healthy individuals, but distinctive for each type of fluid. cfDNA from plasma had variable apoptosis patterns in different healthy individuals. cfDNA in salvia had very variable but extensive damage including prominent single-stranded breaks. cfDNA in cell-free urine showed predominantly a necrosis pattern. Blood cell DNA had minimal DNA damage in healthy individuals, but DNA from urinary sediment cells had both apoptosis and necrosis patterns. cfDNA from sepsis patients had specific damage patterns and platinum-treated cancer patients had detectable interstrand crosslinks.
Conclusions: NLA has implications for cfDNA biology and cfDNA-based assays. Specific disease patterns might have diagnostic value. cfDNA patterns of damage might also be used as a companion diagnostic to assess therapeutic efficiency or side effects in cancer therapy.
