Systemic travel of damaged DNA in photosensitive autoimmune disorders

PROJECT SUMMARY/ABSTRACT The genome in human skin is routinely damaged by ultraviolet (UV) radiation and other environmental genotoxins that are known to induce systemic inflammation. My recent work demonstrates that keratinocytes exposed to UVB radiation release small extracellular vesicles (EVs) with DNA containing cyclobutane pyrimidine dimers (CPDs), or adduct-containing DNA (acDNA), that are capable of being taken up by bystander cells. My preliminary evidence indicates CPD transport to lymph nodes in mice, and others have measured CPD excretion in human urine. However, the role of extracellular environmental genotoxin-damaged DNA in systemic inflammatory responses has not previously been explored. Many patients with autoinflammatory disorders, such as lupus, have photosensitivity. Moreover, nearly two-thirds present with reduced activities of nucleases that degrade immunogenic circulating extracellular DNA. The lack of understanding about the role of extracellular acDNA in autoimmune disorders presents a major gap in the field. Thus, the objective of this application is to test my hypothesis that deficiencies in serum nuclease activity and the presence of UV photoproducts in EVs compound systemic inflammatory responses in patients with photosensitive autoimmune disorders. First, Aim 1 (K99) seeks to demonstrate CPD content in urine EVs and correlate acDNA content with lupus disease severity indicators and serum nuclease activity. To further map systemic circulation and impact of acDNA, Aim 2 (K99/R00) will measure acDNA transfer to organs and damage-dependent responses in mouse models of lupus with nuclease deficiencies. Lastly, Aim 3 (R00) will define mechanisms of release and response of acDNA in EVs in context of common autoimmune nuclease deficiencies. These findings will have broad applicability to the NIEHS because our model of UVB-damaged DNA transfer is expected to extend to other acDNA-inducing environmental genotoxins. Thus, my research findings may improve treatments for photosensitive autoimmune disorders and provide new ways of quantifying environmental genotoxin exposure. The training in this K99/R00 proposal seeks to expand upon my background in chemistry, biology, and skin explant research. I will solidify training in the use of mouse models and human subjects research so that I may establish an independent lab researching the impact of damaged DNA and EVs in photosensitive autoimmune disease. This training will be facilitated by the strong translational research environment at Wright State University. Drs Travers, Brown, and Mahoney (external) bring expertise in extracellular particle characterization and immunogenic response, while Dr. Kemp is an expert in DNA damage responses, and Dr. Crawford is an expert in epidemiology. I will also continue my education to obtain my masters in Clinical Trials Coordination and train through courses in epidemiology and biostatistics through the WSU Department of Population and Public Health Sciences. Thus, this K99/R00 award will enable my transition to an independent research faculty capable of performing strong translational research on the impact of circulating damaged DNA.