👤 Stephanie Teal

To identify novel genetic loci associated with differences in serum etonogestrel concentrations among contraceptive implant users. We conducted a cross-sectional analysis in which we enrolled healthy, reproductive-aged (age 18-45 years) participants who had been using etonogestrel implants for 12-48 months. Participants underwent a single-time blood draw for measurement of serum etonogestrel concentrations by liquid chromatography-tandem mass spectrometry and the extraction of DNA from whole blood. We genotyped participants using the Illumina Infinium Global Diversity Array with Enhanced PGx and imputed genotyping results using the TOPMed imputation server. We performed genome-wide complex trait analysis using a linear mixed model leave-one-chromosome-out association analysis to identify genetic variants associated with serum etonogestrel concentrations. We enrolled 900 etonogestrel implant users, with a median age of 22.3 years (range 18.0-41.5 years), median body mass index (BMI) 26.0 (range 18.5-52.0), and median duration of implant use 27 months (range 12-48 months). Most participants self-reported their race as White (49.3%) and ethnicity as Hispanic or Latina (52.9%). Participants had a median serum etonogestrel concentration of 126.9 pg/mL (range 39.4-695.1 pg/mL). Including BMI, duration of implant use, and three principal components as covariates in the genome-wide complex trait analysis, we identified no genetic variants with minor allele frequencies at or above 5% that were associated with serum etonogestrel concentrations at genome-wide significance ( Despite enhanced coverage for known pharmacogenomic variants, we found no significant associations between interindividual variability in contraceptive implant pharmacokinetics and genetic loci directly involved in exogenous steroid hormone metabolism. ClinicalTrials.gov, NCT03092037. Show less

Epstein Barr virus (EBV), like other oncogenic viruses, modulates the activity of cellular DNA damage responses (DDR) during its life cycle. Our aim was to characterize the role of early lytic proteins and viral lytic DNA replication in activation of DNA damage signaling during the EBV lytic cycle. Our data challenge the prevalent hypothesis that activation of DDR pathways during the EBV lytic cycle occurs solely in response to large amounts of exogenous double stranded DNA products generated during lytic viral DNA replication. In immunofluorescence or immunoblot assays, DDR activation markers, specifically phosphorylated ATM (pATM), H2AX (γH2AX), or 53BP1 (p53BP1), were induced in the presence or absence of viral DNA amplification or replication compartments during the EBV lytic cycle. In assays with an ATM inhibitor and DNA damaging reagents in Burkitt lymphoma cell lines, γH2AX induction was necessary for optimal expression of early EBV genes, but not sufficient for lytic reactivation. Studies in lytically reactivated EBV-positive cells in which early EBV proteins, BGLF4, BGLF5, or BALF2, were not expressed showed that these proteins were not necessary for DDR activation during the EBV lytic cycle. Expression of ZEBRA, a viral protein that is necessary for EBV entry into the lytic phase, induced pATM foci and γH2AX independent of other EBV gene products. ZEBRA mutants deficient in DNA binding, Z(R183E) and Z(S186E), did not induce foci of pATM. ZEBRA co-localized with HP1β, a heterochromatin associated protein involved in DNA damage signaling. We propose a model of DDR activation during the EBV lytic cycle in which ZEBRA induces ATM kinase phosphorylation, in a DNA binding dependent manner, to modulate gene expression. ATM and H2AX phosphorylation induced prior to EBV replication may be critical for creating a microenvironment of viral and cellular gene expression that enables lytic cycle progression. Show less