Sun Yuxiao, Jin Mei-Fang, Li Lili, Liu Yueying, Wang Dandan, Ni Hong
Division of Brain Science, Institute of Pediatric Research, Children's Hospital of Soochow University, Suzhou, China.
The First Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, China.
Front Neurosci. 2022 Mar 24;16:751489. doi: 10.3389/fnins.2022.751489. eCollection 2022.
Hypoxia-ischemia (HI) is the most common acute brain threat in neonates and a leading cause of neurodevelopmental impairment. Exploring the new molecular mechanism of HI brain injury has important clinical translational significance for the next clinical intervention research. Lipid phosphatase-related proteins (PLPPRs) are regulators of mitochondrial membrane integrity and energy metabolism. We recently found that knockout exacerbated HI impairment in some aspects and partially attenuated the neuroprotective effects of melatonin, suggesting that may be a novel intervention target for HI. The present study aimed to determine the long-term effects of gene knockout of on HI brain injury, focusing on the neuronal excitability phenotype, and to determine the effect of gene silencing on neuronal zinc metabolism and mitochondrial function . 10-day-old wild type (WT) mice and -deficient ( ) mice were subjected to hypoxia-ischemia. Lesion volumes and HI-induced neuroexcitotoxic phenotypes were quantified together with ZnT1 protein expression in hippocampus. In addition, HT22 (mouse hippocampal neuronal cells) cell model was established by oxygen-glucose deprivation/reoxygenation (OGD/R) treatment and was treated with medium containing LV-sh_ or control virus. Mitochondrial oxidative stress indicator ROS, mitochondrial ZnT1 protein expression and zinc ion content were detected.
-deficient mice subjected to hypoxia-ischemia at postnatal day 10 present significantly higher cerebral infarction. -deficient mice were endowed with a more pronounced superexcitability phenotype at 4 weeks after HI, manifested as a reduced seizure threshold. ZnT1 protein was also found reduced in -deficient mice as well as in mice subjected to HI excitotoxicity. knockout exacerbates HI brain injury phenotypes, including infarct volume and seizure threshold. In addition, knockout of the gene reduced the MFS score to some extent. silencing directly interferes with neuronal zinc metabolism homeostasis and exacerbates hypoxia-induced mitochondrial oxidative stress damage. Taken together, our findings demonstrate for the first time that -deficient mouse pups exposed to neuronal hypoxia and ischemia exhibit aggravated acute brain injury and long-term brain excitability compared with the same treated WT pups, which may be related to the disruption of zinc and mitochondria-dependent metabolic pathways in the hippocampus. These data support further investigation into novel approaches targeting -mediated zinc and mitochondrial homeostasis in neonatal HIE.
缺氧缺血（HI）是新生儿最常见的急性脑损伤威胁，也是神经发育障碍的主要原因。探索HI脑损伤的新分子机制对后续临床干预研究具有重要的临床转化意义。脂质磷酸酶相关蛋白（PLPPRs）是线粒体膜完整性和能量代谢的调节因子。我们最近发现，基因敲除在某些方面加剧了HI损伤，并部分减弱了褪黑素的神经保护作用，这表明该基因可能是HI的一个新的干预靶点。本研究旨在确定该基因敲除对HI脑损伤的长期影响，重点关注神经元兴奋性表型，并确定该基因沉默对神经元锌代谢和线粒体功能的影响。对10日龄的野生型（WT）小鼠和该基因缺陷（）小鼠进行缺氧缺血处理。对损伤体积和HI诱导的神经兴奋毒性表型进行量化，并检测海马中ZnT1蛋白的表达。此外，通过氧糖剥夺/复氧（OGD/R）处理建立HT22（小鼠海马神经元细胞）细胞模型，并用含有LV-sh_或对照病毒的培养基进行处理。检测线粒体氧化应激指标ROS、线粒体ZnT1蛋白表达和锌离子含量。
出生后第10天遭受缺氧缺血的该基因缺陷小鼠出现明显更高的脑梗死。该基因缺陷小鼠在HI后4周具有更明显的超兴奋性表型，表现为癫痫阈值降低。在该基因缺陷小鼠以及遭受HI兴奋毒性的小鼠中也发现ZnT1蛋白减少。基因敲除加剧了HI脑损伤表型，包括梗死体积和癫痫阈值。此外，该基因敲除在一定程度上降低了MFS评分。该基因沉默直接干扰神经元锌代谢稳态，并加剧缺氧诱导的线粒体氧化应激损伤。综上所述，我们的研究结果首次表明，与相同处理的WT幼崽相比，暴露于神经元缺氧缺血的该基因缺陷幼鼠表现出更严重的急性脑损伤和长期脑兴奋性，这可能与海马中锌和线粒体依赖性代谢途径的破坏有关。这些数据支持进一步研究针对新生儿HIE中该基因介导的锌和线粒体稳态的新方法。
