Institut National de la Recherche Scientifique, Centre Armand-Frappier, Groupe de Recherche en Ingénierie des Peptides et en Pharmacothérapie (GRIPP), Université du Québec, Ville de Laval, QC, Canada; Institut National de la Recherche Scientifique, Centre Armand-Frappier, Laboratoire d'études moléculaires et pharmacologiques des peptides (LEMPP), Université du Québec, Ville de Laval, QC, Canada.
Institut National de la Recherche Scientifique, Centre Armand-Frappier, Université du Québec, Ville de Laval, QC, Canada.
Biochim Biophys Acta Gen Subj. 2019 Nov;1863(11):129398. doi: 10.1016/j.bbagen.2019.07.007. Epub 2019 Jul 12.
The pituitary adenylate cyclase-activating polypeptide (PACAP) type 1 receptor (PAC1), a class B G protein-coupled receptor (GPCR), has emerged as a promising target for treating neurodegenerative conditions. Unfortunately, despite years of research, no PAC1-specific agonist has been discovered, as activity on two other GPCRs, VPAC1 and VPAC2, is retained with current analogs. Cell signaling is related to structural modifications in the intracellular loops (ICLs) of GPCRs. Thus, we hypothesized that peptides derived from the ICLs (called pepducins) of PAC1 might initiate, as allosteric ligands, signaling cascades after recognition of the parent receptor and modulation of its conformational landscape.
Three pepducins were synthesized and evaluated for their ability to 1) promote cell survival; 2) stimulate various signaling pathways associated with PAC1 activation; 3) modulate selectively PAC1, VPAC1 or VPAC2 activation; and 4) sustain mobility and prevent death of dopaminergic neurons in a zebrafish model of neurodegeneration.
Assays demonstrated that these molecules promote SH-SY5Y cell survival, a human neuroblastoma cell line expressing PAC1, and activate signaling via Gα and Gα, with distinct potencies and efficacies. Also, PAC1-Pep1 and PAC1-Pep2 activated selectively PAC1-mediated Gα stimulation. Finally, experiments, using a zebrafish neurodegeneration model, showed a neuroprotective action with all three pepducins and in particular, revealed the ability of PAC1-Pep1 and PAC1-Pep3 to preserve fish mobility and tyrosine hydroxylase expression in the brain.
We have developed the first neuroprotective pepducins derived from PAC1, a class B GPCR.
PAC1-derived pepducins represent attractive templates for the development of innovative neuroprotecting molecules.
垂体腺苷酸环化酶激活肽（PACAP）1 型受体（PAC1）是 B 类 G 蛋白偶联受体（GPCR），已成为治疗神经退行性疾病的有希望的靶点。不幸的是，尽管经过多年的研究，仍未发现 PAC1 特异性激动剂，因为目前的类似物仍保留了对另外两种 GPCR（VPAC1 和 VPAC2）的活性。细胞信号转导与 GPCR 细胞内环（ICL）的结构修饰有关。因此，我们假设 PAC1 的 ICL 衍生肽（称为 pepducins）可能作为别构配体，在识别母体受体并调节其构象景观后，启动信号级联反应。
合成了三种 pepducin 并评估了它们的能力：1）促进细胞存活；2）刺激与 PAC1 激活相关的各种信号通路；3）选择性调节 PAC1、VPAC1 或 VPAC2 的激活；4）维持运动能力并防止神经退行性斑马鱼模型中多巴胺能神经元的死亡。
测定表明，这些分子促进了表达 PAC1 的人神经母细胞瘤细胞系 SH-SY5Y 细胞的存活，并通过 Gα 和 Gα 激活信号，具有不同的效力和效率。此外，PAC1-Pep1 和 PAC1-Pep2 选择性地激活了 PAC1 介导的 Gα 刺激。最后，使用斑马鱼神经退行性变模型进行的实验表明，所有三种 pepducin 均具有神经保护作用，特别是 PAC1-Pep1 和 PAC1-Pep3 能够保持鱼类的运动能力和脑内酪氨酸羟化酶的表达。
我们开发了第一个源自 B 类 GPCR 的 PAC1 神经保护 pepducin。
PAC1 衍生的 pepducin 代表了开发创新神经保护分子的有吸引力的模板。
