Departamento de Medicina Genómica y Toxicología Ambiental, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México.
Free Radic Res. 2013 May;47(5):404-12. doi: 10.3109/10715762.2013.783210. Epub 2013 Apr 8.
Nerve growth factor (NGF) is one of the several structurally related proteins, named neurotrophins (NTs), that regulate neuronal survival, development, function, and plasticity. Moreover, NGF is an important activator of antioxidant mechanisms. These NGF functions are mediated by tropomyosin-related kinase receptor A (TrkA). Although NTs and their receptors have been shown to be expressed in visceral tissues, the extent to which NTs are involved in the physiology of visceral tissues is less clear. NGF is the most expressed NT in adult mouse livers. Although NGF is an important modulator of antioxidant mechanisms in neural tissues, few studies describe the relationship between oxidative stress and NGF expression in the liver. In this study, we demonstrate that ngfb mRNA is positively modulated in mouse livers after oxidative injury via intraperitoneal injection of 14 mg/kg sodium arsenite, 6 mmol/kg L-buthionine-S-R-sulfoximine (BSO), or 300 mg/kg acetaminophen (APAP). In addition to the upregulation of ngfb, we observed the phosphorylation of the NGF high-affinity receptor TrkA in the liver as well as the downstream phosphorylation of Akt, NF-kB nuclear migration and iκbα and tx-1 mRNA upregulation. These effects were abolished when a neutralizing anti-NGF antibody was used. Furthermore, this anti-NGF antibody alone induced oxidative stress in the liver by decreasing the reduced glutathione, increasing the oxidized glutathione, and downregulating tx-1 mRNA. Thus, NGF plays a critical role in liver protection against oxidative stress and xenobiotic injury as well as maintains a reduced thiol state.
神经生长因子(NGF)是几种结构相关蛋白之一,被称为神经营养因子(NTs),它们调节神经元的存活、发育、功能和可塑性。此外,NGF 是抗氧化机制的重要激活剂。这些 NGF 功能是通过原肌球蛋白相关激酶受体 A(TrkA)介导的。尽管已经表明 NTs 及其受体在内脏组织中表达,但 NTs 参与内脏组织生理学的程度尚不清楚。NGF 是成年小鼠肝脏中表达最丰富的 NT。尽管 NGF 是神经组织中抗氧化机制的重要调节剂,但很少有研究描述肝脏中氧化应激与 NGF 表达之间的关系。在这项研究中,我们通过腹腔注射 14mg/kg 亚砷酸钠、6mmol/kg L-丁硫氨酸-S,R-亚砜亚胺(BSO)或 300mg/kg 对乙酰氨基酚(APAP),证明氧化损伤后小鼠肝脏中的 ngfbmRNA 呈正调节。除了 ngfb 的上调外,我们还观察到肝脏中 NGF 高亲和力受体 TrkA 的磷酸化以及 Akt、NF-κB 核迁移和 iκbα 和 tx-1mRNA 的下游磷酸化上调。当使用中和抗 NGF 抗体时,这些作用被消除。此外,这种抗 NGF 抗体本身通过降低还原型谷胱甘肽、增加氧化型谷胱甘肽和下调 tx-1mRNA 来诱导肝脏中的氧化应激。因此,NGF 在肝脏对抗氧化应激和外源性损伤的保护中起着关键作用,并且维持还原型硫醇状态。