HUMAN SERUM BIOMARKER FOR NEUROTOXICITY

该I期申请的目的是开发用于人类药物诱导的神经元损伤的敏感的基于血清的生物标志物。具体而言，我们将评估对乙酰氨基酚过量（OD）后观察到的血清MAP-tau水平升高是否反映了神经元损伤。MAP-tau是主要定位于神经元轴突中的细胞骨架蛋白;在神经元损伤后，MAP-tau被蛋白水解裂解。我们以前的研究表明，脑脊液和血清切割tau蛋白是严重头部创伤后神经元损伤的可靠指标。初步研究表明，对乙酰氨基酚OD患者显示血清切割的tau水平升高，表明对乙酰氨基酚导致神经元损伤。或者，对乙酰氨基酚OD患者可能发生肝毒性。据报道，肝脏MAP-tau水平较低，为脑水平的0.3%。在初步研究中，在任何肝毒性证据之前测定血清切割的tau水平，因此，在OD患者中观察到的血清切割的tau不太可能源自肝脏。我们的特定目标将评估扩大的对乙酰氨基酚OD患者组中的血清切割的tau水平，并且三个特定目标将探索血清切割的tau是否可能是肝脏来源。具体目的1：确定血清裂解tau水平是否在对乙酰氨基酚OD患者中升高，没有肝毒性的证据（N=30）。具体目标二：在因对乙酰氨基酚中毒而住院的患者中，确定血清切割tau水平是否与肝毒性相关（N=30）。具体目标3：确定急性肝衰竭患者（N=30）的血清切割tau水平。具体目标4：表征死后脑、肝和肾样品中的MAP-tau和切割的-tau。拟定商业应用：拟议的体外血清测定可用于评估药物使用、药物过量或环境神经毒素暴露后的脑损伤

The objective of this Phase I application is to develop a sensitive serum- based biomarker for drug-induced neuronal damage in humans. Specifically, we will assess whether elevated serum levels of MAP-tau observed after acetaminophen overdose (OD) reflect neuronal damage. MAP-tau is a cytoskeletal protein primarily localized in neuronal axons; after neuronal damage MAP-tau is proteolytically cleaved. Our previous research demonstrates that cerebrospinal fluid and serum cleaved-tau is a reliable measure of neuronal damage after severe head trauma. Preliminary studies indicate that acetaminophen OD patients demonstrate elevated levels of serum cleaved-tau suggesting that acetaminophen results in neuronal damage. Alternatively, acetaminophen OD patients may develop hepatotoxicity. Low liver MAP-tau levels, 0.3% of brain levels, have been reported. In Preliminary Studies, serum cleaved-tau levels were determined prior to any evidence of hepatotoxicity, therefore, it is unlikely that the serum cleaved-tau observed in OD patients originated from liver. Our Specific Aims will assess serum cleaved-tau levels in an expanded group of acetaminophen OD patients, and three Specific Aims will explore whether serum cleaved-tau may be hepatic origin. Specific Aim 1: Determine if serum cleaved-tau levels are elevated in acetaminophen OD patients with no evidence of hepatotoxicity (N=30). Specific Aim 2: In patients hospitalized with toxic acetaminophen levels determine whether serum cleaved-tau levels are correlated with hepatotoxicity (N=30). Specific Aim 3: Determine serum cleaved-tau levels in patients with acute liver failure (N=30). Specific Aim 4: Characterize MAP-tau and cleaved-tau in post mortem brain, liver and kidney samples. PROPOSED COMMERCIAL APPLICATION: The proposed in vitro serum assay may be utilized to assess brain damage after drug use, drug overdose or environmental neurotoxin exposure