Exploring how age impacts the TNF-mediated activation of monocytes

单核细胞是一种多效性髓系免疫细胞，在先天免疫和体内平衡调节过程的启动和协调中起着关键作用，也是特化免疫效应物和抗原提呈细胞的重要储存库。巨噬细胞和树突状细胞)。虽然它们可以通过各种机制被激活，但细胞因子肿瘤坏死因子(TNF)在这一过程的调节中是基本的，以旁分泌和自分泌的方式发挥作用。众所周知，单核细胞在刺激后会放大和维持反应，最近的研究表明，肿瘤坏死因子也可能通过抑制NFkB，这一机制被称为肿瘤坏死因子耐受，介导逐渐恢复到静息状态。由于在单核细胞反应中，肿瘤坏死因子既可以作为“燃料”，也可以作为“灭火剂”，因此调节肿瘤坏死因子介导的激活和耐受机制具有特别重要的意义。在许多哺乳动物物种中进行的研究表明，单核细胞的表型和功能广泛地受到年龄的影响。然而，与从童年过渡到成年再到老年的常见和过于简化的概念不同，单核细胞随着年龄的增长表现出各种变化，而细胞免疫功能总是会降低。其中一个特征是典型信号通路的失调，如前面提到的NFkB，它们通常被证明在静息状态下过度活跃，在受到刺激时反应不足；细胞因子的产生通常也是如此。肿瘤坏死因子信号如何与这些扰动有关还不得而知，但我们假设它发挥了基础性作用。因此，在下面的提案中，我们旨在研究单核细胞调节中肿瘤坏死因子介导的激活和耐受的动态，以及它如何随着年龄的变化而变化。具体地说，我们将：1)研究单核细胞对外源性肿瘤坏死因子的年龄相关反应。2)检测青年和老年单核细胞经肿瘤坏死因子预暴露后的表型和TLR反应。3)确定预先暴露的肿瘤坏死因子是否影响单核细胞向巨噬细胞的分化和随后的功能。这一全面的研究计划不仅将加深我们对单核细胞激活调控机制的了解，还将产生关于单核细胞随年龄变化的新发现。此外，它还将成为细胞和分子生物学、免疫学和生物信息学等领域的高素质人才(HQP)培训的多学科平台。总体而言，这代表了我们总体目标的一个基本组成部分，即推进单核细胞与其微环境之间的相互作用的知识，特别是免疫因素如何调节这一过程。

Monocytes are pleiotropic myeloid immune cells that play a critical role in the initiation and coordination of innate immune and homeostatic regulatory processes, as well as acting as an important reservoir for specialized immune effector and antigen presenting cells (ie. macrophages and dendritic cells). Although they can be activated through a variety of mechanisms, the cytokine tumour necrosis factor (TNF) is fundamental in the regulation of this process, acting in both a paracrine and autocrine manner. Well-known to amplify and sustain monocyte responses following stimulation, recent work indicates that TNF may also mediate the gradual return to a resting state via the repression of NFkB, a mechanism known as TNF-tolerance. Since TNF can act as both "fuel" and "extinguisher" during monocyte responses, the regulation of mechanisms governing TNF-mediated activation and tolerance is of exceptional importance. Studies performed in a number of mammalian species indicate that monocyte phenotype and function is broadly impacted by aging. However, unlike the common and oversimplified conception that transitions from childhood to adulthood to old age invariably results in a reduction in cellular immune function, monocytes exhibit a variety of alterations with age. One such feature is a dysregulation of canonical signalling pathways such as the aforementioned NFkB, which are often shown to be over-active at a resting state and under-responsive when stimulated; cytokine production generally follows suit. How TNF-signalling is related to these perturbations is very much unknown, but we hypothesize that it plays a fundamental role. Hence, in the following proposal we aim to investigate the dynamics of TNF-mediated activation and tolerance in the regulation of monocytes and how it changes with age. Specifically, we will: 1)Investigate the age-related responses of monocytes to exogenous TNF. 2)Examine the phenotype and TLR-responses of young and old monocytes following TNF pre-exposure. 3)Determine if TNF pre-exposure impacts monocyte to macrophage differentiation and subsequent function. This comprehensive research plan will not only further our knowledge of the regulatory mechanisms governing monocyte activation, it will generate novel findings regarding their evolution with age. Furthermore, it will serve as a multidisciplinary platform for highly qualified personnel (HQP) training in areas such as cellular and molecular biology, immunology, and bioinformatics. Overall, this represents a fundamental component of our overarching goal to advance knowledge of the cross-talk between monocytes and their microenvironment, and specifically, how immunological factors mediate this process.