Moudio Serge, Nuthall Hugh N, Bushell Trevor J
Strathclyde Institute of Pharmacy & Biomedical Sciences, University of Strathclyde, Glasgow, UK.
Centre Hospitalier de Luxembourg, Luxembourg City, Luxembourg.
Brain Neurosci Adv. 2025 Jun 5;9:23982128251345673. doi: 10.1177/23982128251345673. eCollection 2025 Jan-Dec.
Protease-activated receptor 2 is proposed to be a novel target for several inflammation-related diseases but its role in the central nervous system remains unclear. Protease-activated receptor 2 activation is protective in cell death and excitotoxicity assays whereas examination into the role of protease-activated receptor 2 has been hindered due to the lack of suitable pharmacological tools. Recently, a small molecule protease-activated receptor 2 activator, AC264613 (AC), was reported to be a potent and selective protease-activated receptor 2 activator that crosses the blood-brain barrier. Furthermore, peptide mimetic molecules, for example GB88, were developed that were reported to act as protease-activated receptor 2 biased antagonists. Here, we examine their signalling pathways and neuroprotective properties in central nervous system preparations. AC induced significant increases in intracellular Ca in both neurons and astrocytes of primary hippocampal cultures, whereas in contrast, GB88 induced a small but significant reduction in intracellular Ca in both cell types. However, both AC and GB88 induced receptor internalisation when examined using fluorescently tagged protease-activated receptor 2. Both AC and GB88 did not induce neurotoxicity in organotypic hippocampal slice cultures when applied alone but reduced neurotoxicity when co-applied with kainate in excitotoxicity assays. Furthermore, both AC and GB88 reduced neurotoxicity when applied post kainate insult indicating they exhibit neuroprotective properties even after excitotoxicity is induced. These data indicate that protease-activated receptor 2 activation is neuroprotective but this is independent of Gq-induced Ca activation. Given that AC crosses the blood-brain barrier, this highlights its use as a novel tool to examine the protective properties of protease-activated receptor 2 in models of central nervous system disorders.
蛋白酶激活受体2被认为是几种炎症相关疾病的新靶点，但其在中枢神经系统中的作用仍不清楚。蛋白酶激活受体2的激活在细胞死亡和兴奋性毒性试验中具有保护作用，然而由于缺乏合适的药理学工具，对蛋白酶激活受体2作用的研究受到了阻碍。最近，一种小分子蛋白酶激活受体2激活剂AC264613（AC）被报道是一种强效且选择性的蛋白酶激活受体2激活剂，可穿过血脑屏障。此外，还开发了肽模拟分子，例如GB88，据报道其可作为蛋白酶激活受体2的偏向性拮抗剂。在此，我们在中枢神经系统制剂中研究它们的信号通路和神经保护特性。AC在原代海马培养物的神经元和星形胶质细胞中均诱导细胞内Ca显著增加，而相比之下，GB88在两种细胞类型中均诱导细胞内Ca少量但显著减少。然而，当使用荧光标记的蛋白酶激活受体2进行检测时，AC和GB88均诱导受体内化。单独应用时，AC和GB88在器官型海马切片培养物中均未诱导神经毒性，但在兴奋性毒性试验中与海藻酸共同应用时可降低神经毒性。此外，在海藻酸损伤后应用AC和GB88均可降低神经毒性，表明它们即使在诱导兴奋性毒性后仍具有神经保护特性。这些数据表明蛋白酶激活受体2的激活具有神经保护作用，但这与Gq诱导的Ca激活无关。鉴于AC可穿过血脑屏障，这突出了其作为一种新工具在中枢神经系统疾病模型中研究蛋白酶激活受体2保护特性的用途。
