Florio Pasquale, Gazzolo Diego, Luisi Stefano, Petraglia Felice
Department of Pediatrics, Obstetrics and Reproductive Medicine, University of Siena, Siena, Italy.
Adv Clin Chem. 2007;43:117-30. doi: 10.1016/s0065-2423(06)43004-3.
Activin A is a growth factor composed of two betaA subunits belonging to the transforming growth factor beta (TGF-beta) superfamily of dimeric proteins. The biological activity of activin A is mediated by two different types of receptors, the type I (ARI and ARIB) and the type II receptors (ARII and ARIIB), and by two activin-binding proteins, follistatin and follistatin-related gene. These factors bind to activin A and thereby inhibit its biological effects. Activin A, its receptors, and binding proteins are widely distributed throughout the brain. Studies employing models of acute brain injury strongly implicate enhanced activin A expression as a common response to acute neuronal damage of various origins. Hypoxic/ischemic injury, mechanical irritation, and chemical damage of brain evoke a strong upregulation of activin A. Subsequent experimental studies have shown that activin A has a beneficial role to neuronal recovery and that, by activating different pathways, activin A has robust neuroprotective activities. Because activin A induction occurs early after brain injury, its measurement may provide a potential biochemical index of the presence, location, and extent of brain injury. This approach may also facilitate the diagnosis of subclinical lesions at stages when monitoring procedures are unable to detect brain lesion and furthermore establish a prognosis.
激活素A是一种生长因子，由两个βA亚基组成，属于二聚体蛋白的转化生长因子β（TGF-β）超家族。激活素A的生物学活性由两种不同类型的受体介导，即I型受体（ARI和ARIB）和II型受体（ARII和ARIIB），以及两种激活素结合蛋白，即卵泡抑素和卵泡抑素相关基因。这些因子与激活素A结合，从而抑制其生物学效应。激活素A、其受体和结合蛋白广泛分布于整个大脑。采用急性脑损伤模型的研究强烈表明，激活素A表达增强是对各种原因引起的急性神经元损伤的常见反应。脑缺氧/缺血损伤、机械刺激和化学损伤会引起激活素A的强烈上调。随后的实验研究表明，激活素A对神经元恢复具有有益作用，并且通过激活不同途径，激活素A具有强大的神经保护活性。由于激活素A在脑损伤后早期就会诱导产生，其检测可能为脑损伤的存在、位置和程度提供一个潜在的生化指标。这种方法还可能有助于在监测程序无法检测到脑损伤的阶段诊断亚临床病变，并进一步确定预后。
