The Effects of Leptin on Dendritic Cells

瘦素是一种多效性细胞因子/激素，已被证明主要在食物摄入中起关键作用 和能量消耗，但也参与免疫系统功能，包括抗原功能 提呈细胞（APC）。在构成APC的三种细胞群中，只有树突状细胞（DC） 具有启动初始T细胞应答的能力。我们的目标是评估瘦素在DC中的潜在作用， 特别是当通过瘦素受体的信号传导受损时，例如在患有 肥胖或II型糖尿病患者。我们发现，分析DC分离和富集从脾leptindeficient 小鼠（Lepob），当与来自小鼠（Lepob）的脾DC相比时，一些但不是全部的DC功能受到影响。 对照C57 B1/6小鼠。初步数据显示，DC确实表达瘦素受体的长亚型 因此可以对瘦素有反应。Leptin缺乏不改变DC表型，DC活化由 炎症刺激或抗原加工;然而，瘦素缺乏确实影响DC获得 抗原并有效地激活T细胞。我们还发现，在骨骼中加入外源性瘦素， 骨髓来源的DC改变了DC的形态，促进更多和更长的延伸， 提高了特区的生存能力我们假设瘦素缺乏小鼠的DC中瘦素信号传导减少， 正常情况下，瘦素增强DC存活和树突 形成，从而增强APC - T细胞相互作用，导致最佳的T细胞活化。我们建议 我们的假设有三个具体目标。目的1将确定在细胞中表达的 使用标准Western印迹分析和Q-PCR检测DC上瘦素受体的亚型。目标2将 通过评估DC的诱导来确定瘦素是否在与T细胞共培养时增强DC存活 并将通过大量显微镜检查来确定瘦素是否增强了DC - T细胞缀合物的形成 技术.最后，目标3将评估瘦素对DC中信号传导事件的诱导。更具体地说， 促存活信号通路的诱导将通过生物化学方法进行评估， 将通过显微镜检查和生化分析进行评估。考虑到潜在的影响， eptin对DC成熟和功能的影响（如我们的初步数据所示），对瘦素信号传导的抵抗 在肥胖和2型糖尿病中发生的tiat可能损害DC功能，因此T细胞介导的 免疫强调了了解瘦素在免疫中的作用的临床意义。

Leptin is a pleiotropic cytokine/hormone that has been shown to primarily play a critical role on food intake and energy expenditure but is also a participant in functions of the immune system, including that of antigen presenting cells (APCs). Of the three cell populations that constitute APCs, only one, dendritic cells (DC) have the ability to initiate naive T cell responses. Our goal is to assess the potential role of leptin on DC function particularly when signaling through the leptin receptor is compromised, such as in patients afflicted with obesity or Type II Diabetes. We have found, analyzing DC isolated and enriched from spleens of leptindeficient mice (Lepob), that some, but not all, of DC functions are affected when compared to splenic DC from control C57BI/6 mice. Preliminary data has shown that DC do express the long isoform of the leptin receptor and therefore can be responsive to leptin. Leptin-deficiency does not alter DC phenotype, DC activation by inflammatory stimuli, or processing of antigen; however, leptin-deficiency does affect DC ability to acquire antigen and to effectively activate T cells. We have also found that the addition of exogenous leptin to bone marrow-derived DC alters the morphology of the DC, promoting more and longer extensions and also enhances DC survival. We hypothesize that leptin signaling is reduced in DC from leptin-deficient mice due to a reduction in leptin receptor density and that normally, leptin enhances DC survival and dendrite formation thereby enhancing APC - T cell interactions leading to optimal T cell activation. We propose to address our hypothesis with three specific aims. Aim 1 will determine the relative expression levels of the ong isoform of the leptin receptor on DC using standard Western blot analysis and Q-PCR. Aim 2 will ascertain if leptin enhances DC survival when in co-culture with T cells by assessing the induction of DC apoptosis and will ascertain if leptin enhances DC - T cell conjugate formation by a number of microscopy techniques. Lastly, Aim 3 will evaluate the induction of signaling events in DC by leptin. More specifically, the induction of pro-survival signaling pathways will be evaluated biochemically and the induction of actin reorganization will be assessed via microscopy and biochemical assays. Considering the potential influence of eptin on DC maturation and function (as suggested by our preliminary data), resistance to leptin signaling tiat occurs in the obese and in type 2 diabetes may compromise DC function and thus T cell-mediated mmunity underscoring the clinical significance of understanding the role of leptin in immunity.