Circulating nucleic acids damage DNA of healthy cells by integrating into their genomes
Indraneel Mittra Naveen Kumar Khare Gorantla Venkata Raghuram Rohan Chaubal Fatema Khambatti Deepika Gupta Ashwini Gaikwad Preeti Prasannan Akshita Singh Aishwarya Iyer Ankita Singh Pawan Upadhyay Naveen Kumar Nair Pradyumna Kumar Mishra Amit Dutt
Whether nucleic acids that circulate in blood have any patho-physiological functions in the host have not been explored. We report here that far from being inert molecules, circulating nucleic acids have significant biological activities of their own that are deleterious to healthy cells of the body. Fragmented DNA and chromatin (DNAfs and Cfs) isolated from blood of cancer patients and healthy volunteers are readily taken up by a variety of cells in culture to be localized in their nuclei within a few minutes. The intra-nuclear DNAfs and Cfs associate themselves with host cell chromosomes to evoke a cellular DNA-damage-repair-response (DDR) followed by their incorporation into the host cell genomes. Whole genome sequencing detected the presence of tens of thousands of human sequence reads in the recipient mouse cells. Genomic incorporation of DNAfs and Cfs leads to dsDNA breaks and activation of apoptotic pathways in the treated cells. When injected intravenously into Balb/C mice, DNAfs and Cfs undergo genomic integration into cells of their vital organs resulting in activation of DDR and apoptotic proteins in the recipient cells. Cfs have significantly greater activity than DNAfs with respect to all parameters examined, while both DNAfs and Cfs isolated from cancer patients are more active than those from normal volunteers. All the above pathological actions of DNAfs and Cfs described above can be abrogated by concurrent treatment with DNase I and/or anti-histone antibody complexed nanoparticles both in vitro and in vivo. Taken together, our results that circulating DNAfs and Cfs are physiological, continuously arising, endogenous DNA damaging agents with implications to ageing and a multitude of human pathologies including initiation of cancer.
Indraneel Mittra1 Naveen Kumar Khare1 Gorantla Venkata Raghuram1 Rohan Chaubal2 Fatema Khambatti1 Deepika Gupta1 Ashwini Gaikwad1 Preeti Prasannan1 Akshita Singh1 Aishwarya Iyer1 Ankita Singh2 Pawan Upadhyay2 Naveen Kumar Nair1 Pradyumna Kumar Mishra1 Amit Dutt3
Volume 47, 2022
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