Characterization of Siva in Nervous System Development and Apoptosis

描述（由申请人提供）：中枢神经系统中凋亡程序的激活根据具体情况有不同的后果。尽管细胞凋亡对于胚胎神经系统的正常发育至关重要，但在神经损伤后和成人神经退行性疾病中发生的细胞死亡具有有害的后果。p53肿瘤抑制因子是细胞死亡的调节因子，已知在神经管适当关闭和神经元疾病的细胞凋亡中发挥作用。为了更好地了解p53诱导细胞凋亡的机制，我们对细胞死亡过程中p53选择性激活的靶基因进行了筛选，并确定了促凋亡基因Siva。我们已经证明，在培养的神经元中，Siva既足以诱导细胞死亡，也是dna损伤诱导的p53依赖性细胞凋亡所必需的。此外，初步结果表明，我们产生的Siva小鼠显示胚胎致死并伴有神经管闭合缺陷。这个项目的总体目标是更好地定义1)湿婆在神经系统发育中的作用和2)湿婆在神经元细胞死亡中的作用机制。为了了解Siva在神经管闭合和大脑发育中的发育功能，我们将对胚胎发生期间的Siva表达进行详细分析，并对与Siva缺乏相关的表型进行仔细的形态学和组织学检查。在Siva损失中观察到的缺陷的分子基础将通过检查细胞凋亡，增殖和分化标记来研究。为了阐明Siva在细胞凋亡中的作用机制，我们将描述神经元中Siva表达诱导的细胞凋亡的特征，并定义Siva诱导细胞死亡的凋亡机制的必要组成部分。鉴于p53依赖性细胞凋亡在神经元疾病中的作用，Siva可能导致以神经元丢失为特征的人类神经系统疾病，无论是在急性神经元损伤后，如缺血性中风和创伤性脑损伤，还是在神经元丢失的慢性疾病中，包括阿尔茨海默病、帕金森病和亨廷顿病。因此，我们对湿婆的分析将为先天性神经系统疾病和成人神经元疾病提供见解，湿婆可能代表着治疗以神经细胞过度死亡为特征的疾病的有希望的治疗靶点。细胞凋亡是细胞自杀的一种形式，在胚胎神经系统发育过程中起着重要作用，但在神经元损伤和成人神经退行性疾病中具有有害后果。我们对神经元细胞死亡的有效诱导剂Siva基因的分析，将为先天性神经系统疾病和成人神经元疾病提供见解。此外，由于其在神经元凋亡中的作用，Siva代表了治疗以神经细胞过度死亡为特征的疾病的有希望的治疗靶点。

DESCRIPTION (provided by applicant): Activation of an apoptotic program in the central nervous system has different consequences depending on the specific context. Whereas apoptosis is essential for proper embryonic nervous system development, cell death occurring following neuronal injury and in neurodegenerative disease in adults has detrimental consequences. The p53 tumor suppressor is a regulator of cell death known to play a role both in proper neural tube closure and in apoptosis in neuronal diseases. To better understand the mechanism of p53- induced apoptosis, we performed a screen for target genes activated by p53 selectively during cell death, and we identified the pro-apoptotic gene Siva. We have shown that Siva is both sufficient to induce cell death and necessary for DNA-damage-induced, p53-dependent apoptosis in cultured neurons. Moreover, preliminary results indicate that Siva null mice we generated display embryonic lethality accompanied by neural tube closure defects. The overall goal of this project is to better define both 1) Siva's role in nervous system development and 2) Siva's mechanism of action in neuronal cell death. To understand Siva's developmental function in neural tube closure and brain development, we will perform a detailed analysis of Siva expression during embryogenesis coupled with a careful morphological and histological examination of the phenotypes associated with Siva-deficiency. The molecular basis of the defects observed upon Siva loss will be investigated by examining apoptosis, proliferation and differentiation markers. To elucidate the mechanism of action of Siva in apoptosis, we will characterize those features of apoptosis induced by Siva expression in neurons, and define components of the apoptotic machinery essential for Siva-induced cell death. Given the role of p53-dependent apoptosis in neuronal disease, Siva may contribute to human neurological disorders characterized by neuronal loss, either after acute neuronal injury, such as following ischemic stroke and traumatic brain injury, or in chronic diseases of neuronal loss, including Alzheimer's, Parkinson's, and Huntington's. Thus, our analyses of Siva will provide insight into congenital nervous system disorders and adult neuronal diseases and Siva may represent a promising therapeutic target for treating diseases characterized by excessive neuronal cell death. Apoptosis is a form of cellular suicide that plays an important part in sculpting the embryonic nervous system during development, but has detrimental consequences following neuronal injury and in neurodegenerative disease in adults. Our analyses of the gene Siva, a potent inducer of cell death in neurons, will provide insight into both congenital nervous system disorders and adult neuronal diseases. Moreover, because of its role in neuronal apoptosis, Siva represents a promising therapeutic target for treating diseases characterized by excessive neuronal cell death.