Defective Ca2+ signalling between B cells and regulatory T cells: connecting the dots in the emergence of impaired peripheral B cell tolerance in multiple sclerosis?

目前的建议旨在促进我们的理解的分子机制，调节控制的致病性B细胞在多发性硬化症（MS），自身免疫介导的脱髓鞘疾病的中枢神经系统（CNS）。最近的证据表明，外周B细胞耐受性受损导致MS患者中致病性B细胞的频率升高。这可能是由于T细胞非依赖性过程中B细胞调节的畸变，或通过调节性T细胞（T细胞）介导的T细胞依赖性过程引起的。正如我们和其他人以前所显示的那样，MS患者的TGFAP功能缺陷。它们的抑制特性的丧失是通过幼稚细胞的收缩和外周Treg细胞区室中记忆表型的相互扩增而沉淀的，这反过来可能由过早的免疫衰老引起。目前，对于B细胞是否是Tcl4的直接靶点以及它们如何实现对B细胞效应功能如免疫球蛋白产生、抗原呈递和细胞因子分泌的抑制知之甚少。此外，虽然已知通过B细胞调节效应T细胞应答，但B细胞是否也影响Treg活性的问题尚未解决。由于两种细胞亚群之间的双向相互作用的任何损害都可能对MS患者的自身免疫反应的发展产生有害后果，因此我们的目的是更详细地分析B细胞和TCFs之间的串扰。我们打算采用单细胞的活体成像来测量TcB调节周围各种表型的B细胞中的Ca 2+信号传导的能力，这是TcB用于赋予常规T细胞（Tcons）抑制的关键机制，如我们先前所示。通过评估钙离子振荡模式和钙离子驱动的B细胞激活下游事件之间的相关性，将补充成像实验。补充实验的目的是阐明B细胞是否直接影响T细胞的功能能力。

The present proposal intends to advance our understanding of the molecular mechanisms regulating the control of pathogenic B cells in multiple sclerosis (MS), an autoimmune-mediated demyelinating disorder of the central nervous system (CNS). Recent evidence has revealed that an impaired peripheral B cell tolerance accounts for heightened frequencies of pathogenic B cells in patients with MS. This might arise through aberrations in B cell regulation from T cell-independent processes, or through T cell-dependent processes mediated by regulatory T cells (Tregs). Tregs are functionally deficient in patients with MS as we and others have previously shown. Their loss of suppressive properties is precipitated by a contraction of naive cells and reciprocal expansion of memory phenotypes in the peripheral Treg cell compartment, which in turn, possibly arises from premature immunosenescence. At present, little is known as to whether B cells are direct targets of Tregs and how they achieve suppression of B cell effector functions such as immunoglobulin production, antigen presentation, and cytokine secretion. Furthermore, while Modulation of effector T cell responses through B cells is known to occur, the question whether B cells also impact Treg activity has not been addressed. Since any impairment in the bi-directional interaction between the two cell subsets might have harmful consequences on developing autoimmune responses in patients with MS, we aim to analyze the cross-talk between B cells and Tregs in more detail. We intend to employ live Imaging of single cells to measure the capacity of Tregs to modulate Ca2+ signaling in surrounding B cells of various phenotypes, which is a key mechanism utilized by Tregs to confer suppression in conventional T cells (Tcons) as we have previously shown. The imaging experiments will be complemented by assessing the correlation between Ca2+ oscillation patterns and Ca2+-driven downstream events of B cell activation. Complementary experiments aim to clarify whether B cells directly influence the functional capacity of Tregs.