Transciption-independent Signaling by IL1 in Neurons

描述（由申请人提供）：促炎细胞因子白细胞介素1- β (il -1 β)在体内和体外均可抑制下丘脑温敏神经元的活性，这一作用似乎是其作为热原（发烧诱导剂）活性的基础。il -1 β的抑制作用发生在100-300毫秒内，信号机制尚不清楚。影响的速度表明，NFKB介导的转录变化是il -1 β作用的研究最多的信号通路，不太可能是il -1 β快速作用的原因。本研究以热敏下丘脑神经元为模型，探讨il -1 β快速信号转导的分子机制。我们将使用生化和分子生物学、细胞、电生理学和体内遥测方法来确定参与il -1 β对下丘脑温敏神经元的快速作用的第二信使系统，并随后对发热反应产生影响。我们有初步的数据表明，IL-1 β通过1型IL-1受体刺激鞘磷脂酶活性可能参与了IL-1 β的快速信号传导。鞘磷脂酶产物C2神经酰胺的细胞穿透类似物引起快速发热反应，使人想起il -1 β诱导发热的早期阶段。C2神经酰胺在体外激活下丘脑神经元ERK的磷酸化，类似于il -1 β。我们将验证以下假设：il -1 β的快速效应涉及神经酰胺介导的蛋白质磷酸化依赖性神经元活性变化，神经酰胺作为il -1 β快速非转录依赖性作用的第二信使。由于IL-1受体在下丘脑中组成性表达，定义它们的分子作用机制将有助于更好地理解IL-1 β在下丘脑中的神经元作用，在下丘脑中它调节HPA轴、温度设定值和发热反应

DESCRIPTION (provided by applicant): The pro-inflammatory cytokine interleukin 1-Beta (IL-1Beta) suppresses the activity of warm sensitive neurons in the hypothalamus in vivo and in vitro, and this action appears to underlie its activity as a pyrogen (fever-inducing agent). The suppression occurs within 100-300 milliseconds after application of IL-1Beta, and the signaling mechanisms are not known. The speed of the effects suggest that NFKB mediated transcriptional changes, which are the most studied signaling pathways for IL-1Beta action, are not likely to be responsible for this rapid action of IL-1Beta. The goal of this study is to identify the molecular mechanisms of rapid IL-1Beta signaling, using thermosensitive hypothalamic neurons as a model. We will use biochemical and molecular biological, cellular, electrophysiological, and in vivo telemetrical approaches to identify the second messenger system involved in the rapid IL-1Beta effects on hypothalamic warm-sensitive neurons, and subsequently on the fever response. We have preliminary data indicating that IL-1Beta stimulation of sphingomyelinase activity through the type 1 IL-1 receptor may be involved in the rapid signaling of IL-1Beta. The cell penetrating analog of the sphingomyelinase product C2 ceramide causes rapid fever response reminiscent of the early phase of IL-1Beta induced fever. In vitro C2 ceramide activates phosphorylation of ERK in hypothalamic neurons similar to IL-1Beta. We will test the hypothesis that rapid effects of IL-1Beta involve ceramide-mediated protein phosphorylation-dependent changes in neuronal activity and that ceramide acts as second messenger of the rapid non-transcription dependent actions of IL-1Beta. Since IL-1 receptors are constitutively expressed in the hypothalamus, defining their molecular mechanisms of action will contribute to a better understanding of the neuronal effects of IL-1Beta in the hypothalamus, where it regulates the HPA axis, the temperature setpoint, and fever response