Role of IFI 16 in Cellular Senescence and Aging

该提案涉及研究目标#14;了解健康的衰老过程。 细胞衰老或复制性衰老是指已经耗尽其复制潜力的细胞所显示的不可逆的细胞周期停滞。基于几项研究，很明显，衰老细胞随着年龄的增长在细胞更新常见的人体组织和器官中积累。这些研究还提出了衰老细胞的缓慢生长和代谢可能导致衰老过程中的组织衰竭和退行性疾病的可能性。此外，绕过复制衰老可能导致与衰老相关的癌症。因此，识别衰老基因并清楚地了解它们在衰老中的作用， 需要衰老途径来有效地诊断和治疗与衰老有关的疾病。 虽然遗传学研究表明，人类1号染色体的长臂上含有调节衰老的基因，但这些基因的身份仍然未知。我们最近的实验表明，由来自200个基因家族的基因IFI 16（位置1 q22）编码的IFI 16蛋白质的水平在老年人成纤维细胞群体中高于年轻的成纤维细胞。基于这一观察结果和其他人，我们假设基因IFI 16是一个候选人，在文化和体内老化调节复制衰老。具体目标#1：研究IFI 16在复制性衰老中的作用。我们建议：（i）研究当人成纤维细胞在培养中接近复制性衰老时，它们中IFI 16诱导的动力学;（ii） 使用反义方法测量其中IFI 16水平降低的人成纤维细胞中复制性衰老的诱导;和（iii）测量来自互补组C（1号染色体缺陷）的人细胞系中衰老的诱导，以观察这些细胞系的细胞中IFI 16的诱导型（四环素抑制型）表达是否逆转永生表型。具体目标2：目的探讨人成纤维细胞复制性衰老诱导过程中IFI 16基因表达的分子机制。我们将测试是否转录因子KLF 6，肿瘤抑制因子的候选者，激活IFI 16基因的转录。重要性：拟议的研究将测试基因IFI 16是否是调节复制性衰老的候选基因。重要的是，这些研究将提供初步的数据和证据，我们可以执行这些技术的R 01应用。

This proposal addresses Research Objective # 14; Understand Healthy Aging Processes. Cellular senescence or replicative senescence refers to the irreversible cell cycle arrest displayed by cells that have exhausted their replicative potential. Based on several studies, it is evident that senescent cells accumulate with age in human tissues and organs where cell turnover is common. These studies also raise the possibility that the slow growth and metabolism of senescent cells can lead to tissue failure and degenerative diseases during aging. Additionally, bypassing of replicative senescence could lead to aging-related cancers. Therefore, identification of senescence genes and a clear understanding of their role in senescence pathways are needed to diagnose and treat aging-related diseases effectively. Although genetic studies have indicated that the long arm of human chromosome 1 harbors genes regulating senescence, the identities of these genes remain unknown. Our recent experiments indicated that levels of IFI 16 protein, encoded by the gene IFI 16 (location 1q22) from the 200-gene family, are higher in older populations of human fibroblasts than young fibroblasts. Based on this observation and others, we hypothesize that the gene IFI 16 is a candidate for regulating replicative senescence in culture and aging in vivo. Specific aim #1 : To investigate the role of IFI 16 in replicative senescence. We propose to: (i) study the kinetics of IFI 16 induction in human fibroblasts when they approach replicative senescence in culture; (ii) measure the induction of replicative senescence in human fibroblasts in which IFI 16 levels are decreased using an antisense approach; and (iii) measure the induction of senescence in human cell lines from the complementation group C (defective in chromosome 1) to see whether inducible (tetracycline-repressible) expression of IFI 16 in cells of these lines reverses the immortal phenotype. Specific aim #2: To elucidate the molecular mechanism(s) activating the expression of IFI 16 gene during the induction of replicative senescence in human fibroblasts. We will test whether the transcription factor KLF6, a candidate for tumor suppressor, activates transcription of the IFI 16 gene. Siqnificance: The proposed studies will test whether the gene IFI 16 is a candidate for regulating the replicative senescence. Importantly these studies will provide the preliminary data and evidence that we can perform these techniques for an R01 application.