Development Of P2 Receptor Ligands

P2 受体配体的开发

• 批准号: 6810239
• 负责人: Kenneth A Jacobson
• 金额: --
• 依托单位: NATIONAL INSTITUTE OF DIABETES AND DIGESTIVE AND KIDNEY DISEASES
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/6810239
• 关键词: G protein coupled receptor kinase; adenosine; chemical group; drug receptors; inhibitor /antagonist; ligands; membrane channels; positron emission tomography; purinergic receptor; receptor binding; stimulant /agonist

The cloning of at least fifteen subtypes of P2 nucleotide receptors has presented a unique challenge to medicinal chemists: the design of selective agonists and antagonists for this multiplicity of receptors with few existing leads. These receptors regulate function of the central nervous system, the immune system, the cardiovascular system, and smooth muscles. Our laboratory is developing selective agonists and antagonists for these receptors, for use both as pharmacological tools for probing receptor function and as potential therapeutic agents. P2X receptors are ligand-gated ion channels. P2Y receptors are G protein coupled receptors linked to the phosphatidyl inositol pathway as second messenger. The human P2Y1 receptor as representative of the P2Y family of metabotropic purine and pyrimidine nucleotide receptors may be modeled based on a rhodopsin template, and the resulting model is highly consistent with pharmacological and mutagenesis results. Charged residues in both the transmembrane and extracellular domains and two disulfide bridges essential for receptor activation have been identified. Selective P2Y1 receptor antagonists such as the adenine nucleotide MRS 2179 (N-methyl-2'-deoxyadenosine-3',5'-bisphosphate) and it carbocyclic analogue are under development. We have also synthesized nucleotides containing conformationally constrained ribose-like rings, in order to freeze a conformation that provides favorable affinity and/or selectivity at P2 receptors. As a result, we have identified the conformation preference of the P2Y1 receptor for the ?Northern? ring conformation of the ribose. This conclusion applies to both agonists and antagonists. By freezing the ribose substitute in the receptor-preferred conformation, we have enhanced the potency of known agonists at the P2Y1 subtype by 200-300 fold. One ATP derivative containing a methylene carbon joining the second and third phosphate groups was qualitatively altered in its effects on the P2Y1 receptor: The ribose analogue is inactive, and the confromationally constrained analogue (Northern methanocarba) was a moderately potent agonist. The use of conformationally constrained nucleotides has also been extended to P2Y2, P2Y4, P2Y6, and P2Y11 subtypes. The Northern methanocarba ring system results in retention of high potency in agonists at all of the above subtypes, except P2Y6. The conformational requirements of the P2Y6 receptor are currently being explored in our section. Also, a relationship between this subtype and apoptosis, programmed cell death, has been discovered. Astrocytoma cells that express the P2Y6 receptor, when activated by UDP, are protected from apoptosis induced in control cells upon exposure to TNF, tumor necrosis factor. The protection involves activation of protein kinase C and subsequently the signaling kinase known as ERK. This may have relevance for degenerative and inflammatory conditions that involve TNF. A highly potent and selective antagonist of the P2Y1 subtype has been developed using a similar conformational strategy (MRS 2279, which also contains a Northern methanocarba ring system in place of ribose). This compound has been shown to inhibit the ADP-induced aggregation of both rat and human platelets. Its tritiated version is the first high affinity radioligand for the P2Y1 receptor, of general applicability, to be reported. We are continuing the explore the structure activity relationships in this series of potent and selective P2Y1 receptor antagonists. Modeling of P2X receptors has not been achieved, since no template for the extracellular nucleotide binding region exists. Nevertheless, a selective antagonist, MRS 2220, and a potentiator, MRS 2219, of this subtype have been identified. Both are based structurally on pyridoxal-5'-phosphate antagonists (such as PPADS), for which the SAR is being examined at all of the P2 receptor subtypes.

P2核苷酸受体的至少15种亚型的克隆给药物化学家提出了一个独特的挑战：为这种多样性的受体设计选择性激动剂和拮抗剂，而现有的线索很少。这些受体调节中枢神经系统、免疫系统、心血管系统和平滑肌的功能。我们的实验室正在开发这些受体的选择性激动剂和拮抗剂，用作探测受体功能的药理学工具和潜在的治疗剂。P2 X受体是配体门控离子通道。P2 Y受体是作为第二信使与磷脂酰肌醇途径连接的G蛋白偶联受体。作为P2 Y家族的代谢型嘌呤和嘧啶核苷酸受体的代表的人P2 Y1受体可以基于视紫红质模板进行建模，并且所得模型与药理学和诱变结果高度一致。已确定跨膜和细胞外结构域中的带电残基以及受体活化所必需的两个二硫桥。选择性P2 Y1受体拮抗剂，如腺嘌呤核苷酸MRS 2179（N-甲基-2 '-脱氧腺苷-3'，5 '-二磷酸）及其碳环类似物正在开发中。我们还合成了含有构象受限的核糖样环的核苷酸，以冷冻在P2受体上提供有利的亲和力和/或选择性的构象。其结果是，我们已经确定的构象偏好的P2 Y1受体的？北方？核糖的环状构象。这一结论适用于激动剂和拮抗剂。通过将核糖替代物冷冻在受体优选的构象中，我们已经将已知激动剂对P2 Y1亚型的效力提高了200-300倍。一种含有连接第二和第三磷酸基团的亚甲基碳的ATP衍生物在其对P2 Y1受体的作用方面发生了定性改变：核糖类似物无活性，构象限制类似物（北方甲烷卡巴）是一种中等效力的激动剂。构象约束核苷酸的使用也已扩展到P2 Y2、P2 Y 4、P2 Y 6和P2 Y11亚型。北方甲烷卡巴环系统导致在所有上述亚型的激动剂中保留高效力，除了P2 Y 6。P2 Y 6受体的构象要求目前正在我们的部分进行探讨。此外，这种亚型和细胞凋亡，程序性细胞死亡之间的关系已经被发现。表达P2 Y 6受体的星形细胞瘤细胞，当被UDP激活时，在暴露于TNF（肿瘤坏死因子）时，被保护免于在对照细胞中诱导的凋亡。这种保护包括激活蛋白激酶C，随后激活称为ERK的信号激酶。这可能与涉及TNF的退行性和炎症性疾病有关。已经使用类似的构象策略开发了P2 Y1亚型的高效和选择性拮抗剂（MRS 2279，其也含有代替核糖的北方甲烷碳环系统）。该化合物已显示出抑制ADP诱导的大鼠和人血小板聚集。它的氚化版本是第一个高亲和力的放射性配体的P2 Y1受体，普遍适用性，要报告。我们正在继续探索这一系列有效的和选择性的P2 Y1受体拮抗剂的构效关系。P2 X受体的建模尚未实现，因为不存在细胞外核苷酸结合区的模板。然而，已经鉴定了该亚型的选择性拮抗剂MRS 2220和增效剂MRS 2219。两者在结构上均基于吡哆醛-5 '-磷酸拮抗剂（如PPADS），目前正在检查所有P2受体亚型的SAR。