Kirby D A, Koerber S C, May J M, Hagaman C, Cullen M J, Pelleymounter M A, Rivier J E
Clayton Foundation Laboratories for Peptide Biology, Salk Institute, La Jolla, California 92037, USA.
J Med Chem. 1995 Oct 27;38(22):4579-86. doi: 10.1021/jm00022a024.
Neuropeptide Y (NPY), a 36-residue polypeptide produced abundantly in both nervous and peripheral tissues, appears to play a significant role in the regulation of diverse biological processes, including feeding behavior and cardiovascular and psychotropic functions. The actions of NPY are mediated through effective binding to specific receptors of which two, designated Y1 and Y2, have been well characterized. A shortened cyclic analogue of NPY, des-AA10-17-cyclo-7/21[Cys7,21]NPY, was shown to retain high affinity for both human neuroblastoma SK-N-MC and SK-N-BE2 cell types (expressing Y1 and Y2 receptors, respectively). Increasing the size of the ring (des-AA10-17-cyclo-2/27[Cys2,27]NPY) in the present study produced a high-affinity analogue (Ki = 3.0 vs 0.3 nM for NPY) that bound exclusively to Y2 receptors. Using the feedback from structure-activity relationships, we also describe the optimization of specific substitutions and bridging arrangements leading to the production of other truncated, high-affinity Y1 selective analogues which bind, as does NPY itself, in the low-nanomolar range. Of greatest significance, des-AA10-17-cyclo-7/21[Cys7,21,Pro34]NPY (11) was found to possess agonistic properties with an affinity comparable to that of the native NPY molecule when tested for its ability to inhibit norepinephrine-stimulated cAMP release in SK-N-MC human neuroblastoma cells. Compound 11 also caused an increase in blood pressure in anesthetized rats. However, in two central nervous system models of Y1 receptor function, stimulation of feeding and anxiolytic activity, this analogue was inactive, which suggests the presence of a new subclass of receptors. In summary, the present results demonstrate that residues 10-17 of NPY are not directly involved in either Y1 or Y2 receptor recognition or activation. This suggests that the selectivity of NPY receptors is highly dependent on subtle conformational changes such as the substitution of residue 34 to a proline or the introduction of intramolecular constraints. Additionally, we have produced an analogue of NPY that selectively activates peripheral NPY Y1 receptors.
神经肽Y（NPY）是一种在神经组织和外周组织中大量产生的36个氨基酸残基的多肽，似乎在多种生物过程的调节中发挥重要作用，包括摄食行为、心血管功能和精神功能。NPY的作用是通过与特定受体的有效结合介导的，其中两种受体，即Y1和Y2，已得到充分表征。一种缩短的NPY环类似物，des-AA10-17-cyclo-7/21[Cys7,21]NPY，对人神经母细胞瘤SK-N-MC和SK-N-BE2细胞类型（分别表达Y1和Y2受体）均显示出高亲和力。在本研究中，增大环的大小（des-AA10-17-cyclo-2/27[Cys2,27]NPY）产生了一种高亲和力类似物（NPY的Ki = 3.0对0.3 nM），该类似物仅与Y2受体结合。利用构效关系的反馈，我们还描述了特定取代和桥连排列的优化，从而产生了其他截短的、高亲和力的Y1选择性类似物，这些类似物与NPY本身一样，在低纳摩尔范围内结合。最重要的是，当测试des-AA10-17-cyclo-7/21[Cys7,21,Pro34]NPY（11）抑制SK-N-MC人神经母细胞瘤细胞中去甲肾上腺素刺激的cAMP释放的能力时，发现它具有激动特性，其亲和力与天然NPY分子相当。化合物11还导致麻醉大鼠血压升高。然而，在Y1受体功能的两种中枢神经系统模型中，即刺激摄食和抗焦虑活性方面，该类似物无活性，这表明存在一种新的受体亚类。总之，目前的结果表明，NPY的10-17位氨基酸残基不直接参与Y1或Y2受体的识别或激活。这表明NPY受体的选择性高度依赖于细微的构象变化，如将34位残基替换为脯氨酸或引入分子内限制。此外，我们已经产生了一种选择性激活外周NPY Y1受体的NPY类似物。
