Roles for DevelopmentallyRegulated microRNAs in Neonatal Immunity

项目概要/摘要 新生儿极易受到感染，并且由于不充分的原因对疫苗接种反应不佳 明白了。根据我们公布的数据，我们认为新生儿特别容易重复 感染，因为它们的幼稚 CD8 T 细胞在分化为记忆 CD8 T 细胞方面存在本质缺陷。 这笔赠款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 CD8 T 细胞之间。由于 microRNA (miRNA) 受到发育调控， CD8 T 细胞功能所必需的，我们假设生命早期有缺陷的 CD8 T 细胞记忆形成可能 这是由于新生儿和成人 CD8 T 细胞之间 miRNA 表达模式的差异所致。来测试我们的 假设，我们使用下一代测序来识别小鼠 miRNA，这些 miRNA 在 新生儿和成人 CD8 T 细胞贯穿对感染的反应。令人惊讶的是，我们的结果表明 miRNA 表达谱的差异在免疫攻击之前最为明显，表明 发育调节的 miRNA 并不是通过改变效应细胞在发育高峰期的命运来发挥作用的 回应。相反，这些 miRNA 似乎在感染前设定了激活阈值，导致新生儿 CD8 T 细胞可以更快地分化为效应细胞，并使它们远离记忆前体细胞 命运。我们对两种 miRNA（miR-29 和 miR-130）特别感兴趣，我们认为它们在 小鼠和人类的新生儿和成人 CD8 T 细胞之间存在细胞内在差异。 MiR-130 是 优先在新生儿 CD8 T 细胞中表达，并针对一些参与负调控的基因 T 细胞增殖或凋亡。另一方面，MiR-29 在成人 CD8 T 细胞中含量更高，并且 调节参与效应细胞和记忆细胞分化的转录因子的表达。我们建议 miR-29/miR-130 轴充当发育变阻器，用于调节 CD8 T 的激活阈值 细胞，控制快速效应细胞（新生儿）和长寿命记忆细胞（成人）之间的平衡。的 该提案的主要目标是确定 miR-29 和 miR-130 表达与年龄相关的变化如何 改变 CD8 T 细胞对感染的反应能力（目标 1）；鉴定miR-调控的关键靶基因 激活前的 29 和 miR-130（目标 2）；并确定 miR-29 和 miR-130 是否可以预测疫苗- 新生儿的特异性 CD8 T 细胞反应（目标 3）。实现这些目标将为新的 模型描述了 miRNA 如何调节 CD8 T 细胞对感染的反应，这可以产生新的 促进生命早期记忆 CD8 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.