Glucuronidation et sulfatation du 24S-Hydroxycholestérol : rôles complémentaires dans le contrôle de l'homéostasie de ce marqueur du métabolisme neuronal
|Abstract:||24S-hydroxycholesterol (24S-OH) is an oxidized derivative of cholesterol detected in the human plasma. It acts as a Liver-X-Receptor (LXR) agonist and its plasmatic levels have also proposed as potential biomarkers for several neurodegenerative diseases. Circulating 24S-OH levels are influenced by its hepatic elimination but the enzymatic processes involved in its conjugation in the liver have only received limited attention. After analysis of human plasma samples by LC-MS/MS, the 24S-hydroxycholesterol-3 sulfate, 24S-hydroxycholesterol-24 glucuronide and 24S-hydroxycholesterol-3 sulfate, 24-glucuronide were identified. The enzymes responsible for their formation in the liver are identified as UGT1A4 and SULT2A1. In addition, while the sulfated derivative shows a LXR agonist activity, glucuronidated derivatives are inactive. These results indicate that 24S-OH glucuronidation and sulfation affect differently its biological activity. Since UGT1A4 is regulated by LXRα, it can be envisioned that 24S-OH hepatic metabolism is controlled by a feedback loop.|
|Document Type:||Mémoire de maîtrise|
|Open Access Date:||24 April 2018|
|Collection:||Thèses et mémoires|
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