RT Journal Article SR Electronic T1 Quantification of Total and Mutant Huntingtin Protein Levels in Biospecimens Using a Novel alphaLISA Assay JF eneuro JO eNeuro FD Society for Neuroscience SP ENEURO.0234-18.2018 DO 10.1523/ENEURO.0234-18.2018 VO 5 IS 4 A1 Barbara Baldo A1 Muhammad Umar Sajjad A1 Rachel Y. Cheong A1 Julie Bigarreau A1 Ravi Vijayvargia A1 Catriona McLean A1 Anselme L. Perrier A1 Ihn Sik Seong A1 Glenda Halliday A1 Åsa Petersén A1 Deniz Kirik YR 2018 UL http://www.eneuro.org/content/5/4/ENEURO.0234-18.2018.abstract AB The neurodegenerative Huntington’s disease (HD) is caused by a polyglutamine (polyQ) amplification in the huntingtin protein (HTT). Currently there is no effective therapy available for HD; however, several efforts are directed to develop and optimize HTT-lowering methods to improve HD phenotypes. To validate these approaches, there is an immediate need for reliable, sensitive, and easily accessible methods to quantify HTT expression. Using the AlphaLISA platform, we developed two novel sensitive and robust assays for quantification of HTT in biological samples using commercially available antibodies. The first, a polyQ-independent assay, measures the total pool of HTT, while the second, a polyQ-dependent assay, preferentially detects the mutant form of HTT. Using purified HTT protein standards and brain homogenates from an HD mouse model, we determine a lower limit of quantification of 1 and 3 pm and optimal reproducibility with CV values lower than 7% for intra- and 20% for interassay. In addition, we used the assays to quantify HTT in neural stem cells generated from patient-derived induced pluripotent stem cells in vitro and in human brain tissue lysates. Finally, we could detect changes in HTT levels in a mouse model where mutant HTT was conditionally deleted in neural tissue, verifying the potential to monitor the outcome of HTT-lowering strategies. This analytical platform is ideal for high-throughput screens and thus has an added value for the HD community as a tool to optimize novel therapeutic approaches aimed at modulating HTT protein levels.