Parkinson’s disease (PD) is a chronic neurodegenerative condition characterized by motor symptoms such as bradykinesia, resting tremor, and rigidity. PD diagnosis is based on medical history, review of signs, symptoms, neurological and physical examinations. Unfortunately, by the time the disease is diagnosed, dopamine (DA) neuronal loss is often extended, thereby resulting in ineffective therapies. Recent evidence suggests that neuroinflammation may be pivotal during PD onset and progression. However, suitable cellular models and biomarkers to detect early signs of neuroinflammation are still missing. In this study, we developed a well-differentiated DAergic neuronal cell line where we triggered a neuroinflammatory response to assess the temporal expression of the tissue- and urokinase plasminogen activators (tPA and uPA) and their endogenous inhibitor (PAI-1) along with that of pro-inflammatory mediators and the neuronal marker nNOS. Human neuroblastoma cells SH-SY5Y were differentiated into DAergic neuronal-like cells using a combination of 12-O-tetradecanoylphorbol-13-acetate (TPA) and serum depletion. Terminally-differentiated neurons were then exposed to lipopolysaccharide (LPS) for short (up to 24 h) or long term (up to 10 days) to mimic acute or chronic inflammation. Results demonstrated that uPA protein expression was stably upregulated during chronic inflammation, whereas the expression of nNOS protein better reflected the cellular response to acute inflammation. Additional studies revealed that the temporal induction of uPA was associated with increased AKT phosphorylation, but did not seem to involve cAMP-responsive element-binding protein (CREB) activation, nor the mitogen-activated protein kinase (MAPK) pathway. In conclusion, our in vitro data suggests that nNOS and uPA may serve as viable candidate biomarkers of acute and chronic neuroinflammation.

帕金森氏病（PD）是一种慢性神经退行性疾病，其特征在于运动症状，例如运动迟缓，静息性震颤和僵硬。PD诊断的依据是病史，体征，症状，神经和身体检查。不幸的是，在诊断出该疾病时，多巴胺（DA）神经元损失通常会扩大，从而导致无效的治疗。最近的证据表明，神经炎症可能在PD发作和进展过程中起关键作用。但是，仍然缺少用于检测神经炎症早期迹象的合适的细胞模型和生物标记。在这个研究中，我们开发了高度分化的DAergic神经元细胞系，在其中触发了神经炎症反应，以评估组织和尿激酶纤溶酶原激活物（tPA和uPA）及其内源性抑制剂（PAI-1）和促炎性物质的时间表达介体和神经元标记物nNOS。使用12-O-十四烷酰佛波醇13-乙酸盐（TPA）和血清耗竭的组合，将人神经母细胞瘤细胞SH-SY5Y分化为DA能神经元样细胞。然后将终末分化的神经元短期（长达24小时）或长期（长达10天）暴露于脂多糖（LPS），以模拟急性或慢性炎症。结果表明，uPA蛋白的表达在慢性炎症过程中稳定上调，而nNOS蛋白的表达更好地反映了细胞对急性炎症的反应。进一步的研究表明，uPA的暂时诱导与AKT磷酸化增加有关，但似乎不涉及cAMP反应元件结合蛋白（CREB）激活，也不涉及丝裂原激活的蛋白激酶（MAPK）途径。总之，我们的体外数据表明，nNOS和uPA可以作为急性和慢性神经炎症的可行候选生物标记。