Intercellular Integration of SCN Output Signals

在上一个项目的过程中，我们对哺乳动物昼夜节律组织的理解 由于有证据表明体内许多外周组织和 体外的成纤维细胞系也表达典型钟表机构的分子组分中的振荡。 然而，尽管有这些振荡特性，外周组织和成纤维细胞系不能起作用， 通过调节其他细胞或下游过程的昼夜节律来调节心脏起搏器。仅导出振荡器 来自视交叉上核（SCN）的神经元具有恢复行为节律的能力， 移植到SCN损伤的主机，并协调分子和生理振荡， 培养细胞SCN振荡器的起搏器功能可能来自于 它们的输出在SCN内的小区自主时钟之间调解蜂窝通信， 从SCN到下游振荡器。使用永生化大鼠SCN细胞（SCN 2.2），我们已经表明， 在其他共培养的细胞中，起搏器对昼夜节律的调节是由SCN特异性扩散因子介导的。 因素因此，本项目的长期目标是确定传播的输出， 节律性，以其他细胞类型的体外共培养物，并恢复昼夜车轮运行行为时， 移植到体内的寄生虫宿主中。实验将使用多方面的方法来确定 是否：1）反义/siRNA和/或药理学抑制昼夜节律可扩散信号的候选物 在SCN 2.2细胞或它们的受体/反应元件中， 下游细胞; 2）表达特异性输出信号的永生化SCN细胞的克隆系能够 在共培养的细胞中产生内源性振荡和协调节律;和3）克隆SCN细胞 体外具有起搏器特性的线也赋予SCN损伤的大鼠行为节律性， 具有突变昼夜节律表型的转基因小鼠。这些研究将产生新的信息，如何SCN 昼夜节律输出协调不同下游组织和细胞中的振荡， 过程区分SCN振荡器作为昼夜节律起搏器的功能。摘要：这样 信息将导致新的发展，在理解，诊断和治疗疾病， 人体健康和性能可能是由身体过程的内部去角质化引起的， 抑郁症、睡眠障碍、糖尿病、肥胖症和致癌作用。

During the course of the previous project, our understanding of the organization of the mammalian circadian system changed considerably as a result of evidence indicating that many peripheral tissues in vivo and fibroblast cell lines in vitro also express oscillations in molecular components of the canonical clockworks. Yet, despite these oscillatory properties, peripheral tissues and fibroblast cell lines cannot function as pacemakers by regulating circadian rhythms in other cells or downstream processes. Only oscillators derived from the suprachiasmatic nucleus (SCN)possess the capability to restore behavioral rhythmicity when transplanted into SCN-lesioned hosts, and to coordinate molecular and physiological oscillations in co- cultured cells. The pacemaker function of SCN oscillators is presumably derived from the distinctive nature of their outputs that mediate cellular communication between cell-autonomous clocks within the SCN and from the SCN to downstream oscillators. Using immortalized rat SCN cells (SCN2.2), we have shown that pacemaker regulation of circadian rhythms in other co-cultured cells is mediated by SCN-specific diffusible factors. Therefore, the long-term objective of this project is to identify the diffusible outputs that communicate rhythmicity to co-cultures of other cell types in vitro and restore circadian wheel-running behavior when transplanted into arrhythmic hosts in vivo. Experiments will use multi-faceted approaches to determine whether: 1) antisense/siRNA and/or pharmacological inhibition of candidates for circadian diffusible signals in SCN2.2 cells or their receptor/response elements in co-cultured cells disrupts rhythmicity in these downstream cells; 2) clonal lines of immortalized SCN cells that express a specific output signal are capable of generating endogenous oscillations and coordinating rhythms in co-cultured cells; and 3) clonal SCN cell lines with pacemaker properties in vitro also confer behavioral rhythmicity to SCN-lesioned rats and transgenic mice with mutant circadian phenotypes. These studies will yield novel information on how SCN circadian outputs coordinate oscillations in different downstream tissues and cells, and what cellular processes distinguish the function of SCN oscillators as a circadian pacemaker. Lay Summary: Such information will lead to new developments in the understanding, diagnosis and treatment of disorders in human health and performance that may result from internal desynchronization of body processes such as depression, sleep disturbances, diabetes, obesity and carcinogenesis.