Comprehensive Measurement of Inter-Individual Variation in DNA Repair Capacity in Healthy Individuals

Abstract Rare genetic DNA repair deficiency syndromes can lead to immunodeficiency, neurological disorders, and cancer. In the general population, inter-individual variation in DNA repair capacity (DRC) influences susceptibility to cancer and several age-related diseases. Genome wide association studies and functional analyses show that defects in multiple DNA repair pathways jointly increase disease risk, but previous technologies did not permit comprehensive analyses of DNA repair in populations. To overcome these limitations, we used fluorescence multiplex host cell reactivation (FM-HCR) assays that directly quantify DRC across six major DNA repair pathways. We assessed DRC in phytohemagglutinin-stimulated primary lymphocytes from 56 healthy individuals and validated assay reproducibility in 10 individuals with up to five independent blood draws. We furthermore developed generalized analytical pipelines for systematically adjusting for batch effects and both experimental and biological confounders. Our results reveal significant inter-individual variation in DRC for each of 10 reporter assays that measure the efficiency of distinct repair processes. Our data also demonstrate that correlations between the activities of different DNA repair pathways are relatively weak. This finding suggests that each pathway may independently influence susceptibility to the health effects of DNA damage. We furthermore developed a pipeline for analyzing comet repair kinetics and related our new functional data to previously reported comet assay data for the same individuals. Our pioneering analysis underscores the sensitivity of FM-HCR assays for detecting subtle biological differences between individuals and establishes standardized methodologies for population studies. Our findings and open source analytical tools advance precision medicine by enabling comprehensive exploration of genetic, demographic, clinical, and lifestyle factors and supporting targeted interventions to enhance DNA repair and maintain genomic integrity, thereby promoting personalized healthcare and disease prevention. Competing Interest Statement Z.D.N., I.A.C., and L.D.S. are co-inventors on a related patent (US 9,938,587 B2). Z.D.N. reports past unrelated sponsored research agreements with Pfizer Inc., Ensoma, Agios, and Intellia Therapeutics. Funding Statement The authors acknowledge funding that supported this work from the National Institute of Environmental Health Sciences (U01ES029520 to Z.D.N. and DP1ES022576 to L.D.S). Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: The Committee on the Use of Humans as Experimental Subjects at Massachusetts Institute of Technology gave ethical approval for this work. I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable. Yes Data Availability The data supporting the findings of this study are available within the published article, supplementary information, or source data file.