Role of calcium and reactive oxygen species in toxicant-induced immune failure

细胞内钙离子（Ca 2+）和活性氧（ROS）的稳态调控对细胞的生长和增殖至关重要。 生存和功能。细胞内游离Ca~（2+）和ROS水平的升高在淋巴细胞增殖中起重要作用。 对抗原刺激的反应。ROS和Ca2+相互作用，相互调节： 外源性ROS的应用导致细胞内Ca 2+动员，同时增加细胞质Ca 2 + 浓度诱导淋巴细胞产生ROS。在多环芳烃（PAH）诱导的 淋巴细胞免疫抑制，增强的ROS产生与增加的基础水平有关。 胞内Ca2+。此外，细胞内Ca2+的这些高基础水平不会进一步增加， 对抗原受体刺激的反应。因此，我假设Ca2+和 ROS对于淋巴细胞活化至关重要，并且这种串扰的破坏有助于异常抗原的产生。 PAH免疫抑制中观察到的受体信号通路。因此，我计划调查 正常B细胞受体刺激过程中Ca2 * 和ROS信号传导之间的串扰以及 在PAH的免疫抑制过程中的这种串扰。具体而言，我将追求三个具体目标：（1） 使用电生理学和Ca2+成像，定义Ca2+的药理学和生物物理学特性， 通道的B细胞被激活的外源性应用的活性氧，并决定是否成员 涉及阳离子通道TRPC家族。根据初步实验，TRPC 3和TRPC 5 在HEK293细胞中表达时形成ROS敏感性阳离子通道;（2）确定 在B淋巴细胞中ROS产生中细胞内Ca 2+升高， B细胞中有丝分裂原诱导的ROS产生所必需的;（3）测试细胞内ROS的慢性增加是否与B细胞中的ROS产生有关。 PAH诱导的Ca2+通过ROS依赖性机制和/或膜去极化维持。 初步数据显示，PA和ROS均诱导B细胞中的Ca 2+内流。我期待一段牢固的关系 ROS和Ca2+信号缺陷在PAH诱导的免疫失败之间的关系。这一努力将有助于 更好地了解正常和病理性淋巴细胞免疫以及发现新的 免疫缺陷和癌症等疾病的治疗。

Control of intracellular calcium (Ca2+) and reactive oxygen species (ROS) homeostasis is essential for cell survival and function. Elevation of intracellular free Ca2+ and ROS levels play a central role in lymphocyte activation in response to antigenic stimulation. ROS and Ca2+ exert a reciprocal regulation on each other: exogenous application of ROS leads to intracellular Ca2+ mobilization while increased cytoplasmic Ca2+ concentration induces ROS production by lymphocytes. In polycyclic aromatic hydrocarbons (PAH)-induced lymphocyte immune suppression, enhanced ROS production is associated with increased basal levels of intracellular Ca2+. Furthermore, these high basal levels of intracellular Ca2+ do not increase further in response to stimulation of the antigen receptor. Thus, I hypothesize that the crosstalk between Ca2+ and ROS is vital for lymphocyte activation and that the disruption of this crosstalk contributes to abnormal antigen receptor signaling pathways observed in immune suppression by PAH. Therefore, I plan to investigate the crosstalk between Ca2* and ROS signaling during normal B-cell receptor stimulation as well as the disruption of this crosstalk during immune suppression by PAH. Specifically, I will pursue three specific aims: (1) to define, using electrophysiology and Ca2+ imaging, the pharmacological and biophysical properties of the Ca2+ channels in B-cells that are activated by exogenous application of ROS, and determine whether members of the TRPC family of cation channels are involved. Based on preliminary experiments, TRPC3 and TRPC5 form ROS-sensitive cation channels when expressed in HEK293 cells; (2) to determine the role of intracellular Ca2+ rise in ROS production in B lymphocytes and which membrane-bound NADPH oxidase is necessary for mitogen-induced ROS production in B-cells; (3) to test if the chronic increase of intracellular Ca2+ induced by PAH is maintained by a ROS-dependent mechanism and/or by membrane depolarization. Preliminary data shows that both PAHand ROSinduce Ca2+ entry in B-cells. I excpect a strong relationship between ROS and Ca2+ signaling defects in PAH-induced immune failure. This effort will contribute to both a better understanding of normal and pathological lymphocyte immunity as well as to the discovery of new therapies for diseases such as immunodeficiency and cancer.