Investigating lactate as an inflammatory early signal in ectopic lymphoid neogenesis and its translational impact in patients with autoimmune diseases

异位淋巴样结构(ELs)是指在慢性炎症部位形成的具有次级淋巴器官表型(即T、B淋巴细胞在不同区域分离，间质来源的滤泡树突状细胞网络分化)和功能(即生发中心)特征的淋巴细胞。ELS的形成被描述为器官特异性自身免疫条件、实体肿瘤发生、慢性感染和移植物排斥反应。干燥综合征(SS)是英国第二常见的风湿性自身免疫性疾病，发病率在100,000-250,000之间，女性居多(女性与男性之比为9：1)，30/40%的患者在唾液腺发生ELS。在SS中，具有生发中心的ELs的存在与更严重的疾病和B细胞淋巴瘤的风险增加16倍有关，B细胞淋巴瘤通常发生在受影响的腺体中。ELS的形成机制很大程度上尚不清楚，但似乎是T和B细胞在慢性炎症组织中逐渐积累和组织的结果，淋巴毒素/淋巴趋化因子反馈回路的激活由促炎细胞因子触发，最明显的是IL-17和IL-17相关细胞因子，如IL-22。这些介质主要由CD4+T细胞释放，这对与B细胞的同源相互作用和异位生发中心的发展也是至关重要的。在以前的工作(以及目前正在重新审查的细胞代谢)中，我们证明了乳酸是慢性炎症组织的典型特征，它通过特定的乳酸转运体SCL5A12调节CD4+T细胞，促进Th17细胞的扩张和作为炎症部位的保留。因此，在这项由两所英国大学合作的应用中，我们计划进行一系列全面的体外、体内和体外研究，目的是：1)研究在ELS+和ELS-SS患者以及B细胞枯竭反应和无反应者中，唾液腺和外周血SLC5A12和IL-17的表达是否存在差异调节；2)评估敲除SLC5A12(遗传方法)的影响和阻断SLC5A12(药理学方法)在唾液腺ELS诱导模型和SS唾液腺器官培养中调节ELS的治疗潜力；3)剖析乳酸/SLC5A12对SS患者CD4+T细胞影响的代谢途径。总之，这项建议将强调一条连接代谢和免疫细胞功能的新的关键途径的重要性，通过阐述其对免疫病理损害的发展的影响，该损害与SS密切相关，并且在许多慢性自身免疫/炎症性疾病中常见。在短期内，预计这项工作如果成功，将为一个调查不足的领域带来新的知识，并为SS带来新的知识，SS被认为是一种孤儿疾病，具有明确的未满足的知识和临床需求。重要的是，我们的工作有可能对以ELS形成为特征的其他医疗条件产生影响，包括癌症、慢性感染和移植物排斥反应。我们还预计，通过在ELS小鼠模型和人类器官培养中显示出用我们开发的新型抗SLC512单抗阻断乳酸/SLC5A12途径的“临床”和生物学效果，从长远来看，我们将为将我们的研究转化为患者的利益铺平道路。

Ectopic lymphoid-like structures (ELS) are defined as lymphomonocytic cell clusters forming at sites of chronic inflammation which acquire phenotypic (i.e. segregation of T and B lymphocytes in discrete areas with differentiation of networks of stromal-derived follicular dendritic cells) and functional (i.e germinal centres) features of secondary lymphoid organs. The formation of ELS has been described in organ-specific autoimmune conditions, solid tumorigenesis, in chronic infections and graft rejection. In the context of Sjogren's syndrome (SS), the second most common rheumatic autoimmune disease with a prevalence between 100,000-250,000 in UK and a predominance in women (female to male ration 9:1), ELS develop in the salivary glands in 30/40% of the patients. In SS, the presence of ELS with germinal centres is associated with a more severe disease and a 16-fold higher risk of B cell lymphoma, frequently arising in the affected glands. The mechanisms of ELS formation are largely unknown but appear to be the result of the progressive accumulation and organization of T and B cells within chronically inflamed tissue whereby the activation of the lymphotoxin/lymphoid chemokine feedback loop is triggered by pro-inflammatory cytokines, most notably IL-17 and IL-17 related cytokines such as IL-22. These mediators are primarily released by CD4+ T cells which are critical also for the cognate interaction with B cells and the development of ectopic germinal centres. In previous work (as well as work currently under re-review at Cell Metabolism) we demonstrated that lactate, whose accumulation is a typical feature of chronically inflamed tissues, modulate CD4+ T cells via the specific lactate transporter SCL5A12 promoting an expansion of Th17 cells and their retention as site of inflammation. Thus, in this application, which is a Partnership between 2 UK Universities, we plan to perform a series of comprehensive ex vivo, in vivo and in vitro studies with the aim to: 1) investigate whether salivary glands and peripheral SLC5A12 and IL-17 expression in CD4+ T-cells is differentially regulated in ELS+ vs ELS- SS patients and in responders vs non-responders to B cell depletion; 2) assess the impact of knocking out SLC5A12 (genetic approach) and the therapeutic potential of blocking SLC5A12 (pharmacological approach) in modulating ELS in an inducible murine model of salivary gland ELS and in SS salivary gland organ cultures; 3) dissect the metabolic pathways underlying the observed effects of lactate/SLC5A12 on CD4+ T-cells from SS patients.Overall, this proposal will highlight the importance of a novel key pathway linking metabolism and immune cell function by addressing its impact on the development of immunopathology lesions which are extremely relevant to SS and common to many chronic autoimmune/inflammatory diseases. In the short term, it is envisaged that, if successful, this work will bring new knowledge to a poorly investigated field and to a condition, SS, which is considered an orphan disease with clear unmet knowledge and clinical needs. Importantly, our work has the potential to impact on other medical conditions characterised by the formation of ELS, including cancer, chronic infection and graft rejection. We also anticipate that by showing "clinical" and biological efficacy of blocking the lactate/SLC5A12 pathway with a novel anti-SLC512 monoclonal antibody - which we developed - in a murine model of ELS and in human organ cultures, in the long term we will pave the way towards translation of our research towards patient benefit.