Park, A. H. | Search bioRxiv

bioRxiv2025

REverse-transcriptase ACTivity with CRISPR (REACTR) Assay for Ganciclovir Triphosphate Monitoring

BackgroundCytomegalovirus (CMV) can cause severe disease and death in infants and immunocompromised people. Although effective at treating CMV, the first-line drug - ganciclovir (GCV) - has high rates of pharmacokinetic variability which leads to significant rates of underexposure or toxicity. Intracellular concentrations of ganciclovir triphosphate (GCV-TP) - GCVs active anabolite - are associated with dose-dependent neutropenia and could enable dose individualization to improve treatment efficacy and reduce adverse effects. However, GCV-TP is currently measured using liquid chromatography tandem mass spectrometry (LC-MS/MS) which is impractical for routine use, especially in resource-limited settings, because of its high cost, labor-intensiveness, and need for specialized equipment. To address this gap, we adapted the REverse transcriptase ACTivity with CRISPR (REACTR) assay to measure GCV-TP. MethodsWe leveraged our earlier work using REACTR to measure reverse transcriptase (RT) inhibitors used to treat and prevent human immunodeficiency virus (HIV) because GCV-TP serendipitously also inhibits HIV RT. We designed custom DNA templates, primers, and CRISPR complexes to accurately measure GCV-TP spiked into buffer and blood. We evaluated the assays analytical performance with 40 dried blood spots from infants with congenital CMV. ResultsREACTR reproducibly measured clinically relevant GCV-TP concentrations using a simple workflow and equipment that are readily available in many clinical laboratories. REACTR measurements of clinical samples correlated with LC-MS/MS GCV-TP measurements (r = -0.7891; p<0.0001). ConclusionsThis study highlights the potential of REACTR as a rapid and accessible alternative to LC-MS/MS for therapeutic drug monitoring of GCV.

bioengineering↗

bioRxiv2022

DREADD activation of the lateral septum alters prosocial and antisocial behaviors, but not partner preferences in male prairie voles

Although much has been written on the topic of social behavior, many terms referring to different aspects of social behavior have become inappropriately conflated and the specific mechanisms governing them remains unclear. It is therefore critical that we disentangle the pro- and anti-social elements associated with different forms of social behavior to fully understand the social brain. The lateral septum (LS) mediates social behaviors, emotional processes, and stress responses necessary for individuals to navigate day-to-day social interactions. The LS is particularly important in general and selective prosocial behavior (monogamy) but its role in how these two behavioral domains intersect is unclear. Here, we investigate the effects of chemogenetic-mediated LS activation on social responses in male prairie voles when they are 1) sex-naive and generally affiliative and 2) after they become pair-bonded and display selective aggression. Amplifying neural activity in the LS augments same-sex social approach behaviors. Despite partner preference formation remaining unaltered, LS activation in pair-bonded males leads to reduced selective aggression while increasing social affiliative behaviors. These results suggest that LS activation alters behavior within certain social contexts, by increasing sex-naive affiliative behaviors and reducing pair bonding-induced selective aggression with same-sex conspecifics, but not altering bonding with opposite-sex individuals.

neuroscience↗