Development and validation of CYP26A1 inhibition assay for high-throughput screening
Scientists at NCATS, EPA, and NIEHS are studying how chemicals interact with important biological systems to better predict potential risks, such as developmental toxicity. One key system involves all-trans retinoic acid, a molecule produced from vitamin A, which is crucial for regulating development and cell growth. Levels of all-trans retinoic acid are tightly controlled in the body, and the molecule is broken down by specialized enzymes called CYP26 (subtypes A1, B1, and C1) to maintain balance. This research focused on the detection of chemicals that inhibit CYP26A1, one of the enzymes involved in this process, using a new experimental method.
Researchers developed a high-throughput screening (HTS) assay using a system called P450-Glo (Sakamuru et al. 2024). This cell-free system quickly identifies chemicals that interfere with CYP26A1 activity. The assay performed well in terms of consistency, reliability, and ability to distinguish signals, with a signal-to-background ratio of 25.7 and a Z-factor of 0.7 (indicating strong performance). To validate the method, 39 chemicals were tested, including known CYP26A1 inhibitors, compounds related to retinoids, and control chemicals. The assay accurately confirmed known inhibitors and identified new ones, such as chlorothalonil, prochloraz, and SSR126768. This successful validation highlights the reliability of the new assay in the detection of chemicals that may disrupt all-trans retinoic acid balance, which is critical during development. This innovative tool could be pivotal for studying developmental toxicity and ensuring chemical exposure safety, particularly for substances that impact embryonic development.