Elucidating the differential contribution of sulfonation and glucuronidation in controlling nuclear receptor activity.

基本原理：葡萄糖醛酸化和磺化是2种酶促反应，可将各种疏水性内源性和外源性分子转化为水溶性葡萄糖醛酸苷和/或硫酸盐衍生物。这些衍生物很容易通过胆汁或尿液从活体动物中消除。相应的酶UDP-葡糖醛酸基转移酶和磺基转移酶对各种生物活性激素具有反应性，所述生物活性激素通过胞内分泌、自分泌/旁分泌或内分泌激活细胞内核（NR）或膜受体（例如肝X受体α（LXRa））来控制主要生理过程。初步数据：直到最近，葡萄糖醛酸化和磺化被认为对受体配体起着类似的失活作用。我们最近取得了令人兴奋的发现，即葡萄糖醛酸化完全消除了24 S-羟基胆固醇（24 SOH-Chol）激活LXR α的能力，而相反，磺化增强了其与受体结合的能力。这些观察结果提供了证据，磺化和葡萄糖醛酸化发挥不同的作用，在控制NR驱动的基因转录。该方案的目标：由于许多其他内-和外源性底物的磺化和葡萄糖醛酸化作为受体配体，我们目前的研究计划的首要目标是进一步阐明如何深的差异影响，这2个反应施加在核和膜受体配体活性。短期、中期和长期目标是：-短期（=申请资助期）将在分子水平上评价磺化和葡萄糖醛酸化如何影响NR配体结合和（或）激活其特异性受体的内分泌能力。 - 中期（2026-31年）和长期（>10年）将确定核/膜受体配体的自分泌和旁分泌（中期）和内分泌（长期）活性如何受到2种反应的不同影响。实验设计（短期调查：2021-2026年）：我们将首先进行体外实验，以评估磺化和葡萄糖醛酸化如何影响所选配体的能力（如多酚白藜芦醇、环境内分泌干扰物双酚A、抗雌激素他莫昔芬，以及内源性胆固醇衍生物24 SOH-Chol，CDCA和LCA）结合到它们各自的NR（TR-FRET）并在相关细胞模型中发挥它们的激动（直接或反向）或拮抗活性。然后进行体内分析，以确认体外观察到的事件仍在适当的小鼠模型中发生。结论：通过解释磺化和葡萄糖醛酸化干扰其共同底物的生物活性的不同方式，所提出的研究计划有望在细胞信号传导、代谢领域取得显著进展，并将导致从理解信号传导终止到潜在药物设计的广泛应用。

Rationale: Glucuronidation and sulfonation are 2 enzymatic reactions which turn a variety of hydrophobic endogenous and exogenous molecules into water soluble glucuronide and/or sulfate derivatives. These derivatives are easily eliminated from living animals through the bile or urine. The respective enzymes UDP-glucuronosyltransferase and sulfotransferase enzymes are reactive toward various biologically active hormones that control major physiological processes through the intracrine, auto/paracrine or endocrine activation of intracellular nuclear (NRs) or membrane receptors, such as the Liver X-Receptor alpha (LXRa). Preliminary data: Until recently, glucuronidation and sulfonation were thought to play a similar inactivation role for receptor ligands. We recently made the exciting discovery that glucuronidation totally abolishes the ability of 24S-hydroxycholesterol (24SOH-Chol) to activate LXRa, while in contrast sulfonation reinforces its ability to bind to the receptor. These observations provide evidences that sulfonation and glucuronidation exert differential roles in the control of NR-driven gene transcription. Objectives of the program: Because numerous other endo- and exogenous substrates for sulfonation and glucuronidation act as receptor ligands, the overarching aim of our present research program is to further elucidate how deep is the differential impact that the 2 reactions exert on nuclear and membrane receptor ligands activity. Short, mid and long-term objectives are: - Short term (=requested funding period) will evaluate at the molecular level, how sulfonation and glucuronidation impact the intracrine ability of NR ligands to bind to and (in)activate their specific receptor. - Mid- (2026-31) and long term (>10 years) will determine how the autocrine and paracrine (mid) and endocrine (long) activities of nuclear/membrane receptor ligands are differentially affected by the 2 reactions. Experimental design (short term investigations: 2021-2026): We will first perform in vitro experiments to evaluate how sulfonation and glucuronidation affect the ability of selected ligands (such as the polyphenol Resveratrol, the environmental endocrine disruptor Bisphenol A, the anti-estrogen Tamoxifen, as well as the endogenous cholesterol derivatives 24SOH-Chol, CDCA and LCA) to bind to their respective NR (TR-FRET) and exert their agonistic (direct or inverse) or antagonistic activities in relevant cell models. In vivo analyses will then be performed to confirm that events observed in vitro are still occurring in appropriate mice models. Conclusions: by deciphering the differential manner in which sulfonation and glucuronidation interfere with the biological activity of their common substrates, the proposed research program promises a remarkable advance in the fields of cell signalling, metabolism, and will result in a broad range of applications varying from the understanding of signalling termination to potential drug design.