Stapled Peptides with Therapeutic Potential for Ischemic Stroke by Blocking the Endocytosis of GluA2 AMPAR

Targeting the interaction between the C-terminal domain of the GluA2 subunit of AMPA receptors and BRAG2 presents a highly promising therapeutic approach for acute ischemic stroke. The membrane-permeable peptide Tat-GluA2-3Y has shown potential by competitively binding to BRAG2 to inhibit GluA2 endocytosis; however, its clinical application is limited due to poor stability in vivo. To address this limitation, we developed stapled peptides based on GluA2-3Y, leading to the identification of the lead compound P3LC7LC-P, which exhibits high-affinity binding to BRAG2. Functionally, P3LC7LC-P offers strong neuroprotection in two injury models: oxygen–glucose deprivation-induced and glutamate-induced neurotoxicity. Notably, P3LC7LC-P significantly improved plasma stability compared to Tat-GluA2-3Y, with a half-life exceeding 372.7 min. In the transient middle cerebral artery occlusion (tMCAO) model, P3LC7LC-P reduced cerebral infarction areas to 21.00% at a dose of 8 mg/kg. These findings highlight P3LC7LC-P as a promising candidate for the development of novel therapies for ischemic stroke.靶向α-氨基-3-羟基-5-甲基-4-异恶唑丙酸受体（AMPA receptors）GluA2亚基的C端结构域（C-terminal domain）与BRAG2之间的相互作用，是急性缺血性脑卒中极具潜力的治疗策略。膜通透性肽Tat-GluA2-3Y已展现出应用潜力，可通过竞争性结合BRAG2抑制GluA2内吞作用，但因其体内稳定性较差，临床应用受到限制。为解决这一局限，我们基于GluA2-3Y开发了钉合肽（stapled peptides），并筛选得到先导化合物P3LC7LC-P，该化合物可与BRAG2发生高亲和力结合。功能实验显示，P3LC7LC-P在氧糖剥夺诱导及谷氨酸诱导的两种神经损伤模型中均展现出强效神经保护作用。值得注意的是，相较于Tat-GluA2-3Y，P3LC7LC-P的血浆稳定性得到显著改善，半衰期超过372.7分钟。在短暂性大脑中动脉阻塞（transient middle cerebral artery occlusion, tMCAO）模型中，8 mg/kg剂量的P3LC7LC-P可将脑梗死面积降低至21.00%。上述研究结果表明，P3LC7LC-P是开发缺血性脑卒中新型治疗药物的极具前景的候选化合物。