Roles for DevelopmentallyRegulated microRNAs in Neonatal Immunity

项目摘要/摘要 新生儿很容易受到感染，对疫苗的反应不佳，原因并不是很好。 明白了。根据我们公布的数据，我们认为新生儿特别容易复发 感染是因为他们幼稚的CD8T细胞在分化为记忆性CD8T细胞方面存在内在缺陷。 这项拨款的一个主要目标是确定构成细胞内在差异的关键基因调控网络。 新生儿和成人CD8 T细胞之间的差异。由于microRNAs(MiRNAs)受发育调节和 CD8 T细胞功能所必需的，我们假设在生命早期有缺陷的CD8 T细胞记忆形成可能 可能是由于新生儿和成人CD8 T细胞miRNA表达模式的差异。测试我们的 假设，我们使用下一代测序来识别小鼠miRNAs，这些miRNA在 新生儿和成人的CD8T细胞对感染的反应贯穿始终。令人惊讶的是，我们的结果表明 MiRNA表达谱的差异在免疫学攻击之前最为明显，这表明 发育调节的miRNA不是通过改变效应细胞在细胞生长高峰期的命运来运作的 回应。相反，这些miRNAs似乎在感染之前设置了激活阈值，从而导致新生儿 CD8 T细胞更快分化为效应细胞并使其远离记忆前体 命运。我们对两个miRNAs(miR-29和miR-130)特别感兴趣，我们认为它们在 小鼠和人的新生儿和成人CD8 T细胞之间存在的细胞固有差异。MIR-130是 在新生儿CD8 T细胞中优先表达，并针对一些参与负调控的基因 T细胞增殖或凋亡的可能性。另一方面，MIR-29在成人CD8 T细胞中含量更高， 调节参与效应和记忆细胞分化的转录因子的表达。我们建议 MiR-29/miR-130轴作为发育变阻器调节CD8T的激活阈值 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。这个 这项建议的主要目标是确定miR-29和miR-130表达的年龄相关变化 改变CD8T细胞对感染的反应能力(目标1)；确定由miR-1调控的关键靶基因 29和miR-130在激活前(目标2)；并确定miR-29和miR-130是否可以预测疫苗- 新生儿特异性CD8 T细胞反应(目标3)。实现这些目标将为新的 描述miRNAs如何调节CD8T细胞对感染的反应的模型，这可能导致新的 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.