Unité de Radiobiologie, Département Effets Biologiques des Rayonnements, IRBA-Institut de Recherche Biomédicale des Armées, Place du Général Valérie André, 91223 Brétigny-sur-Orge, France.
Université Paris-Saclay, INSERM, Laboratory of Signalling and Cardiovascular Pathophysiology U1180, 91400 Orsay, France.
Int J Mol Sci. 2024 Feb 14;25(4):2269. doi: 10.3390/ijms25042269.
High-dose irradiation can trigger numerous endothelial dysfunctions, including apoptosis, the overexpression of adhesion molecules, and alteration of adherens junctions. Altogether, these endothelial dysfunctions contribute to the development of tissue inflammation and organ damage. The development of endothelial dysfunctions may depend on protein phosphorylation by various protein kinases, but the possible role of protein kinase A (PKA) has not been investigated so far, and efficient compounds able to protect the endothelium from irradiation effects are needed. Here we report the beneficial effects of the PKA inhibitor KT5720 on a panel of irradiation-induced endothelial dysfunctions in human pulmonary microvascular endothelial cells (HPMECs). High-dose X-irradiation (15 Gy) triggered the late apoptosis of HPMECs independent of the ceramide/P38 MAP kinase pathway or p53. In contrast, the treatment of HPMECs with KT5720 completely prevented irradiation-induced apoptosis, whether applied before or after cell irradiation. Immunostainings of irradiated monolayers revealed that KT5720 treatment preserved the overall integrity of endothelial monolayers and adherens junctions linking endothelial cells. Real-time impedance measurements performed in HPMEC monolayers confirmed the overall protective role of KT5720 against irradiation. Treatment with KT5720 before or after irradiation also reduced irradiation-induced ICAM-1 overexpression. Finally, the possible role for PKA in the development of endothelial dysfunctions is discussed, but the potency of KT5720 to inhibit the development of a panel of irradiation-induced endothelial dysfunctions, whether applied before or after irradiation, suggests that this compound could be of great interest for both the prevention and treatment of vascular damages in the event of exposure to a high dose of radiation.
高剂量照射会引发多种血管内皮功能障碍，包括细胞凋亡、黏附分子过度表达以及黏着连接改变。所有这些内皮功能障碍都有助于组织炎症和器官损伤的发展。内皮功能障碍的发展可能依赖于各种蛋白激酶的蛋白磷酸化，但到目前为止，蛋白激酶 A（PKA）的可能作用尚未被研究，并且需要有效的化合物来保护内皮免受照射效应的影响。在这里，我们报告了 PKA 抑制剂 KT5720 对人肺微血管内皮细胞（HPMEC）中一系列照射诱导的内皮功能障碍的有益作用。高剂量 X 射线照射（15 Gy）可触发 HPMEC 的晚期细胞凋亡，而与神经酰胺/P38 MAP 激酶途径或 p53 无关。相反，KT5720 处理可完全防止照射诱导的细胞凋亡，无论在细胞照射之前或之后进行处理。对照射单层细胞的免疫染色显示，KT5720 处理可维持内皮单层和连接内皮细胞的黏着连接的整体完整性。在 HPMEC 单层中进行的实时阻抗测量证实了 KT5720 对照射的整体保护作用。在照射前后用 KT5720 处理也可降低照射诱导的 ICAM-1 过表达。最后，讨论了 PKA 在血管内皮功能障碍发展中的可能作用，但 KT5720 在抑制一系列照射诱导的内皮功能障碍中的作用，无论是在照射之前还是之后进行处理，都表明该化合物在暴露于高剂量辐射时对预防和治疗血管损伤都具有重要意义。
