The role of ion channels and transporters in B cell function

项目总结/摘要 B细胞是体液免疫应答中的核心参与者，该应答由分化的抗体-T细胞引起。 产生称为浆细胞（PC）的B细胞类型。在病毒感染如流感或SARS-CoV 2期间， PC产生中和病毒活性的抗体。此外，PC已被牵连的发病机制 包括多发性硬化症（MS）在内的许多自身免疫性疾病。因此，调节B细胞功能的能力， 特别是PC分化和活性，具有广泛的临床意义。针对特定调节的领先疗法 B细胞功能的一个关键因素是靶向CD 20的单克隆抗体，导致几乎所有B细胞亚群的快速耗竭 并导致各种副作用。因此，临床上需要影响B细胞功能的分子靶标 以更精致和精确的方式 离子通道和转运蛋白（ICTs）介导离子穿过脂质双层的通量，这可以进一步调节 胞内信号传导ICT是理想的临床靶点，因为1）许多是可接近的表面蛋白， 生物制剂和2）多种小分子ICT调节剂已经被开发出来。但不幸 有大量证据表明，不同的信息和通信技术可以促进B功能的不同方面，这种交叉 仍然没有得到很好的调查。为了解决这一差距，我将利用转录组学分析和功能 基因组学，再加上实验验证。基于RNA-seq和CRISPR筛选， SLC 4A 7，已知调节细胞内pH的Na+/HCO 3-共转运蛋白。B细胞中SLC 4A 7的选择性缺失 体外和体内PC分化受损。在目标1中，我将进一步描述SLC 4A 7如何影响PC 分化信号传导途径、细胞内pH和自噬途径。在目标2中，我将确定如何 B细胞中SLC 4A 7的缺失会影响针对流感感染的免疫应答， 总的来说，这个项目将阐明新的机制， 细胞内pH调节PC分化并揭示B细胞功能新靶点（SLC 4A 7） 可以被调节，特别是在MS的情况下。

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.