International Journal of Molecular Sciences Article Orphan Nuclear Receptor RORα Regulates Enzymatic Metabolism of Cerebral 24S-Hydroxycholesterol through CYP39A1 Intronic Response Element Activation Hiroshi Matsuoka 1,* , Miyu Katayama 1, Ami Ohishi 1, Kaoruko Miya 1, Riki Tokunaga 1, Sou Kobayashi 1, Yuya Nishimoto 1, Kazutake Hirooka 2 , Akiho Shima 1 and Akihiro Michihara 1 1 Laboratory of Genome Function and Pathophysiology, Faculty of Pharmacy and Pharmaceutical Sciences, Fukuyama University, Fukuyama, Hiroshima 729-0292, Japan;
[email protected] (M.K.);
[email protected] (A.O.);
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[email protected] (A.M.) 2 Department of Biotechnology, Faculty of Life Science and Biotechnology, Fukuyama University, Fukuyama, Hiroshima 729-0292, Japan;
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[email protected]; Tel.: +81-84-936-2111 Received: 2 April 2020; Accepted: 6 May 2020; Published: 7 May 2020 Abstract: Oxysterols, important regulators of cholesterol homeostasis in the brain, are affected by neurodegenerative diseases. Early-onset Alzheimer’s disease is associated with higher levels of circulating brain-derived 24S-hydroxycholesterol (24S-OHC). Conversion of cholesterol to 24S-OHC is mediated by cholesterol 24S-hydroxylase in the brain, which is the major pathway for oxysterol elimination, followed by oxidation through hepatic first-pass metabolism by CYP39A1. Abnormal CYP39A1 expression results in accumulation of 24S-OHC, influencing neurodegenerative disease-related deterioration; thus, it is important to understand the normal elimination of 24S-OHC and the system regulating CYP39A1, a selective hepatic metabolic enzyme of 24S-OHC.