Cho Jae Min, Park Seul-Ki, Mookherjee Sohom, Peters Emily Carolyn, Pires Paulo W, Symons J David
Department of Nutrition and Integrative Physiology, Division of Endocrinology, Metabolism and Diabetes, and Program in Molecular Medicine, University of Utah, Salt Lake City, UT, USA.
Division of Cardiology, Department of Medicine, David Geffen School of Medicine, University of California, Los Angeles, CA, USA.
Geroscience. 2025 Apr 12. doi: 10.1007/s11357-025-01650-5.
We have previously reported that when autophagy is suppressed in endothelial cells (ECs), a glycolytic defect limits shear-stress -induced ATP production to an extent that purinergic 2Y1 receptor (P2Y1R)-mediated activation of EC nitric oxide (NO) synthase (eNOS) is compromised. Subsequently we demonstrated the functional relevance of this finding in arteries from mice with genetic, pharmacological, and age-associated EC autophagy impairment. Using gain and loss of function approaches in vitro, we further revealed that p-PKCδ serves as a signaling link between P2Y1R activation and NO generation. Here we sought to discern the functional relevance of this observation. First, shear-stress- induced activating phosphorylation of eNOS (p-eNOS) that is otherwise prevented by knockdown of autophagy-related gene 3 (Atg3) in ECs was restored by the PKC agonist bryostatin-1. Next, in murine models of genetic and age-associated EC autophagy compromise, depressed vasodilation displayed by femoral and cerebral arteries was reversed by bryostatin-1 in a manner that could be prevented by concurrent NO synthase inhibition. Finally, the bryostatin-1-mediated normalization of intraluminal flow-induced vasodilation observed in femoral arteries from both models of EC autophagy disruption was mitigated by inhibiting downstream targets of p-PKCδ i.e., p-PKD and p-PKD. These findings provide evidence that stimulating PKC/PKD has strategic potential to restore compromised endothelial function in pathologies associated with suppressed EC autophagy e.g., aging.
我们之前报道过，当内皮细胞（ECs）中的自噬被抑制时，糖酵解缺陷会限制剪切应力诱导的ATP生成，以至于嘌呤能2Y1受体（P2Y1R）介导的EC一氧化氮（NO）合酶（eNOS）激活受到损害。随后，我们在具有基因、药理学和年龄相关EC自噬损伤的小鼠动脉中证明了这一发现的功能相关性。在体外使用功能获得和功能丧失方法，我们进一步揭示p-PKCδ作为P2Y1R激活与NO生成之间的信号连接。在这里，我们试图了解这一观察结果的功能相关性。首先，ECs中自噬相关基因3（Atg3）的敲低会阻止的剪切应力诱导的eNOS激活磷酸化（p-eNOS），通过PKC激动剂苔藓抑素-1得以恢复。其次，在基因和年龄相关的EC自噬受损的小鼠模型中，股动脉和脑动脉显示的血管舒张功能降低被苔藓抑素-1逆转，其方式可被同时进行的NO合酶抑制所阻止。最后，通过抑制p-PKCδ的下游靶点即p-PKD和p-PKD，苔藓抑素-1介导的在两种EC自噬破坏模型的股动脉中观察到的腔内血流诱导的血管舒张正常化得到缓解。这些发现提供了证据，表明刺激PKC/PKD在恢复与EC自噬抑制相关的病理状态（如衰老）中受损的内皮功能方面具有战略潜力。
