Roles for DevelopmentallyRegulated microRNAs in Neonatal Immunity

项目概要/摘要 新生儿对感染高度敏感，对疫苗接种反应不佳，原因是 明白根据我们发表的数据，我们认为新生儿特别容易重复 感染，因为他们的幼稚CD 8 + T细胞在分化为记忆CD 8 + T细胞方面存在固有缺陷。 这项资助的一个主要目标是确定细胞内在差异背后的关键基因调控网络 新生儿和成人CD 8 + T细胞之间的差异。由于microRNAs（miRNAs）是发育调控的， 由于CD 8 + T细胞的功能是必需的，因此我们假设，早期生命中CD 8 + T细胞记忆形成缺陷可能 这可能是由于新生儿和成人CD 8 + T细胞之间miRNA表达模式的差异。来测试我们 假设，我们使用下一代测序来鉴定小鼠miRNAs，这些miRNAs在以下方面受到差异调节： 新生儿和成人的CD 8 + T细胞在整个感染反应。令人惊讶的是，我们的结果表明， 在免疫攻击前，miRNA表达谱的差异最明显，表明 发育调控的miRNAs并不通过改变效应细胞在发育高峰期的命运来发挥作用， 反应相反，这些miRNAs似乎在感染前设定了激活阈值，导致新生儿 CD 8 + T细胞更快地分化为效应细胞，并使它们远离记忆前体 命运我们特别感兴趣的是两种miRNAs（miR-29和miR-130），我们认为它们在 在小鼠和人类中，新生儿和成人CD 8 + T细胞之间存在细胞内在差异。MiR-130是 优先在新生儿CD 8 + T细胞中表达，并靶向参与负调控的许多基因 T细胞增殖或凋亡。另一方面，MiR-29在成人CD 8 + T细胞中含量更丰富， 调节参与效应细胞和记忆细胞分化的转录因子的表达。我们提出 miR-29/miR-130轴作为发育变阻器调节CD 8 + T细胞活化阈值， 细胞，控制快速效应细胞（新生儿）和长寿记忆细胞（成人）之间的平衡。的 本研究的主要目的是确定miR-29和miR-130表达的年龄相关变化 改变CD 8 + T细胞对感染应答的能力（Aim 1）;确定由miR-1调控的关键靶基因; 29和miR-130之间的差异（目的2）;并确定miR-29和miR-130是否可以预测疫苗的免疫应答。 新生儿中特异性CD 8 + T细胞应答（目的3）。实现这些目标将有助于建立一个新的 描述了miRNAs如何调节CD 8 + T细胞对感染的反应的模型，这可以导致新的 增强生命早期记忆性CD 8 + T细胞发育的治疗策略。

Project Summary /Abstract Neonates are highly susceptible to infection and respond poorly to vaccination for reasons that are not well understood. Based on our published data, we believe that neonates are particularly vulnerable to repeat infections because their naïve CD8+ T cells are intrinsically defective at differentiating into memory CD8+ T cells. A major goal of this grant is to identify the key gene regulatory networks that underlie cell-intrinsic differences between neonatal and adult CD8+ T cells. Since microRNAs (miRNAs) are developmentally regulated and required for CD8+ T cell function, we hypothesized that defective CD8+ T cell memory formation in early life may be due to differences in miRNA expression patterns between neonatal and adult CD8+ T cells. To test our hypothesis, we used next generation sequencing to identify mouse miRNAs that are differentially regulated in neonatal and adult CD8+ T cells throughout the response to infection. Surprisingly, our results indicated that differences in miRNA expression profiles were most pronounced prior to immunological challenge, suggesting that developmentally-regulated miRNAs do not operate by altering the fate of effector cells at the peak of the response. Instead, these miRNAs appear to set the activation threshold prior to infection, causing neonatal CD8+ T cells to differentiate more rapidly into effector cells and biasing them away from a memory precursor fate. We are particularly interested in two miRNAs (miR-29 and miR-130), which we believe play a major role in cell-intrinsic differences that exist between neonatal and adult CD8+ T cells in mice and humans. MiR-130 is preferentially expressed in neonatal CD8+ T cells and targets a number of genes involved in negative regulation of T cell proliferation or apoptosis. MiR-29, on the other hand, is more abundant in adult CD8+ T cells and regulates the expression of transcription factors involved in effector and memory cell differentiation. We propose that the miR-29/miR-130 axis acts as a developmental rheostat for adjusting the activation threshold of CD8+ T cells, controlling the balance between rapid effector cells (neonates) and long-lived memory cells (adults). The main objectives of this proposal are to determine how age-related changes in miR-29 and miR-130 expression alter the ability of CD8+ T cells to respond to infection (Aim 1); identify the key target genes regulated by miR- 29 and miR-130 prior to activation (Aim 2); and determine whether miR-29 and miR-130 can predict vaccine- specific CD8+ T cell responses in newborns (Aim 3). Accomplishing these aims will lend support for a new model describing how miRNAs regulate the CD8+ T cell response to infection, which can lead to novel therapeutic strategies for enhancing the development of memory CD8+ T cells in early life.