The role of ion channels and transporters in B cell function

项目摘要/摘要 B细胞是体液免疫反应的中心参与者，体液免疫反应是由分化的抗体- 产生被称为浆细胞(PC)的B细胞类型。在流感或SARS-CoV2等病毒感染期间， 个人计算机产生中和病毒活性的抗体。此外，在发病机制中也涉及到pcs。 许多自身免疫性疾病，包括多发性硬化症(MS)。因此，调节B细胞功能的能力， 值得注意的是，PC的分化和活性具有广泛的临床意义。特效调控的主导疗法 B细胞功能的关键是针对CD20的单抗，导致几乎所有B细胞亚群的迅速耗尽 并导致各种副作用。因此，临床上需要寻找影响B细胞功能的分子靶点 以更精致和精确的方式。 离子通道和转运体(ICT)调节跨脂双层的离子流量，从而进一步调节 细胞内信号。ICT是理想的临床靶点，因为1)许多是表面蛋白，可与 生物制剂和2)多种小分子ICT调制器已经被开发出来。然而，不幸的是， 大量证据表明，不同的信息和通信技术可以促进B函数的不同方面，这一交集 调查仍然很少。为了解决这一差距，我将利用转录分析和功能 基因组学，加上实验验证。基于RNA-SEQ和CRISPR屏幕，我偶然发现 SLC4A7，一种已知的调节细胞内pH的Na+/HCO3-共转运体。B细胞中SLC4A7基因的选择性缺失 在体外和体内，PC分化受到损害。在目标1中，我将进一步描述SLC4A7如何影响PC 分化信号通路、细胞内pH和自噬途径。在目标2中，我将决定如何 B细胞中SLC4A7的缺失会影响对流感感染的免疫反应以及 多发性硬化小鼠模型的发病机制，本项目将阐明新的机制，通过 细胞内pH调节PC分化并揭示B细胞功能的新靶点(SLC4A7) 可以被调制，特别是在MS的背景下。

PROJECT SUMMARY/ABSTRACT B cells are a central player in the humoral immune response, which is elicited by differentiated, antibody- producing B cell-types known as plasma cells (PCs). During viral infections such as influenza or SARS-CoV2, PCs produce antibodies that neutralize viral activity. Furthermore, PCs have been implicated in the pathogenesis of many autoimmune diseases, including multiple sclerosis (MS). Thus, the capacity to modulate B cell function, notably PC differentiation and activity, has broad clinical implications. The leading therapy for specific regulation of B cell function is a monoclonal antibody targeting CD20, leading to brash depletion of virtually all B cell subsets and resulting in various side effects. Thus, there is a clinical need for molecular targets that affect B cell function in more refined and precise manners. Ion channels and transporters (ICTs) mediate the flux of ions across the lipid bilayer, which can further regulate intracellular signaling. ICTs are desirable clinical targets because 1) many are surface proteins accessible to biologics and 2) multiple small-molecule ICT modulators have already been developed. Unfortunately, though substantive evidence exists that different ICTs can contribute to different aspects of B function, this intersection remains poorly investigated. To address this gap, I will leverage transcriptomic analyses and functional genomics, coupled with experimental validations. Based on an RNA-seq and a CRISPR screen, I came across SLC4A7, a Na+/HCO3- co-transporter known to regulate intracellular pH. Deletion of SLC4A7 in B cells selectively impaired PC differentiation in vitro and in vivo. In Aim 1, I will further characterize how SLC4A7 affects PC differentiation signaling pathways, intracellular pH, and the autophagy pathway. In Aim 2, I will determine how deletion of SLC4A7 in B cells affects the immune response against influenza infection as well as the pathogenesis of a murine model for MS. Overall, this project will elucidate novel mechanisms by which intracellular pH regulates PC differentiation and reveal a novel target (SLC4A7) with which B cell function can be modulated, especially in the context of MS.