Department of Pharmacology and Toxicology, University of Arkansas for Medical Sciences, Little Rock, AR, USA; Department of Clinical Pharmacy, Faculty of Pharmacy, Cairo University, Cairo, Egypt.
Vascular Biology Center, Augusta University, Augusta, GA, USA.
Exp Neurol. 2022 Feb;348:113923. doi: 10.1016/j.expneurol.2021.113923. Epub 2021 Nov 12.
Arginase 1 (A1) is the enzyme that hydrolyzes the amino acid, L-arginine, to ornithine and urea. We have previously shown that A1 deletion worsens retinal ischemic injury, suggesting a protective role of A1. In this translational study, we aimed to study the utility of systemic pegylated A1 (PEG-A1, recombinant human arginase linked to polyethylene glycol) treatment in mouse models of acute retinal and brain injury. Cohorts of WT mice were subjected to retinal ischemia-reperfusion (IR) injury, traumatic optic neuropathy (TON) or brain cerebral ischemia via middle cerebral artery occlusion (MCAO) and treated with intraperitoneal injections of PEG-A1 or vehicle (PEG only). Drug penetration into retina and brain tissues was measured by western blotting and immunolabeling for PEG. Neuroprotection was measured in a blinded fashion by quantitation of NeuN (neuronal marker) immunolabeling of retina flat-mounts and brain infarct area using triphenyl tetrazolium chloride (TTC) staining. Furthermore, ex vivo retina explants and in vitro retina neuron cultures were subjected to oxygen-glucose deprivation (OGD) followed by reoxygenation (R) and treated with PEG-A1. PEG-A1 given systemically did not cross the intact blood-retina/brain barriers in sham controls but reached the retina and brain after injury. PEG-A1 provided neuroprotection after retinal IR injury, TON and cerebral ischemia. PEG-A1 treatment was also neuroprotective in retina explants subjected to OGD/R but did not improve survival in retinal neuronal cultures exposed to OGD/R. In summary, systemic PEG-A1 administration is neuroprotective and provides an excellent route to deliver the drug to the retina and the brain after acute injury.
精氨酸酶 1（A1）是一种酶，可将氨基酸 L-精氨酸水解为鸟氨酸和尿素。我们之前的研究表明，A1 缺失会加重视网膜缺血性损伤，表明 A1 具有保护作用。在这项转化研究中，我们旨在研究系统给予聚乙二醇化 A1（PEG-A1，与聚乙二醇连接的重组人精氨酸酶）治疗在急性视网膜和脑损伤的小鼠模型中的效用。WT 小鼠分为几组，进行视网膜缺血再灌注（IR）损伤、创伤性视神经病变（TON）或大脑中动脉闭塞（MCAO）导致的脑缺血，并用腹腔注射 PEG-A1 或载体（仅 PEG）治疗。通过 Western blot 和 PEG 免疫标记测量药物穿透视网膜和脑组织的程度。通过对视网膜平面标本和脑梗死面积的 NeuN（神经元标志物）免疫标记的定量，以盲法测量神经保护作用，使用氯化三苯基四氮唑（TTC）染色。此外，对离体视网膜外植体和体外视网膜神经元培养物进行氧葡萄糖剥夺（OGD），然后再进行复氧（R），并用 PEG-A1 处理。系统给予的 PEG-A1 在假手术对照中不会穿过完整的血视网膜/脑屏障，但在损伤后可到达视网膜和大脑。PEG-A1 在视网膜 IR 损伤、TON 和脑缺血后提供神经保护作用。PEG-A1 治疗在 OGD/R 后也对视网膜外植体具有神经保护作用，但不能改善暴露于 OGD/R 的视网膜神经元培养物的存活。总之，系统给予 PEG-A1 具有神经保护作用，并为急性损伤后将药物递送至视网膜和大脑提供了极好的途径。
