CALCB基因突变导致浆细胞嗜神经性富集在IgG4相关性疾病中的功能及机制研究

IgG4 related disease (IgG4-RD) is an chronic and progressive autoimmune disease involving multiple organs or tissues. There is great harm to the patients in clinic. Study about its pathogenic mechanism is almost blank. Calcitonin gene related peptide II (beta CGRP) newly discovered is a neurotransmitter with negative regulating function. As we know, beta CGRP is product expressed by the CALCB gene. We first found that CALCB gene had high frequency mutation at p.S30P existing in patients with IgG4-RD (5/26), and there were lots of plasma cells enrichment around the nerves in the patients' involved tissues. This study will focus on the relationship between CALCB mutation and plasma cells enrichment around the nerve and perform the following investigations: 1) Construction mutant CALCB transfect B precursor cell , and then detect the synthesis and position of beta CGRP with combination of chemotaxis and proliferation experiment, so as to explain the mechanism why plasma cells enriched around the nerves. 2) To construct the autoimmune pancreatitis model with WBN/Kob mice and inject CGRP receptor antagonist from tail vein, then we observe whether neurotropic phenomenon of plasma cells become more serious or not. 3) To upregulate expression of CGRP in B precursor cells, then transfer these B precursor cells back to the model mice ,in order to observe whether neurotropic phenomenon of plasma cells become alleviate or not. In brief, this research will probably not only find a new pathogesis of IgG4-RD, but also clarify the new targets for the therapy of IgG4-RD.

IgG4相关性疾病（IgG4-RD）是累及多器官或组织的慢性、进行性、自身免疫性疾病，临床危害极大，但其触发机制的研究近乎空白。降钙素基因相关肽II（βCGRP）是新近发现的具有负向调节功能的神经递质。我们首先发现IgG4-RD患者中存在βCGRP的表达基因—CALCB基因p.S30P高频突变（5/26），而且受累的组织呈现浆细胞嗜神经性富集。本课题将聚焦于CALCB突变与浆细胞嗜神经性富集的关系展开系列研究：1）用突变型CALCB转染鼠B前体细胞，检测βCGRP的合成、定位情况，并结合趋化和增殖实验，解释浆细胞富集和嗜神经机制；2）构建WBN/Kob自身免疫性胰腺炎大鼠模型，尾静脉注射CGRP受体阻滞剂，观察浆细胞嗜神经现象是否加重；3)上调B前体细胞βCGRP的表达，回输模型鼠，观察嗜神经现象是否减轻。本课题将不仅发现IgG4-RD的致病新机制，而且将阐明IgG4-RD治疗的新靶标。

在国家自然科学基金No.81571613支持下，课题组针对自身免疫性胰腺炎等IgG4-相关性疾病的发病机制进行深入研究，共发表基金标注论文13篇，其中SCI收录12篇，影响因子大于5的3篇，二区4篇，包括自然出版集团的《Cell Death﹠Disease》2篇、柳叶刀新子刊《EBioMedicine》、英国皇家学会会刊《Open Biology》、《Inflammation》等，而且多篇论文都已经被正面引用。主要成果体现在以下几点：1.IgG4-RILD疾病特征的临床研究。2.发现神经因子（降钙素基因相关肽基因—CALCB）突变或者异常剪切，导致βCGRP细胞内定位和合成异常，引发神经周围炎和自身免疫性胰腺炎（典型的IgG4-RD）。3.低adropin或者adropin缺乏可造成胰腺脂肪化和DM，并且证明adropin参与脂肪免疫。4.发现了ACIVAbs（胶原IV抗体），为解释自身免疫性胰腺炎等IgG4-RD病理组织中炎症细胞噬神经以及闭塞性血管炎提供有力证据。5.发现ENHO基因变异是导致MPO-ANCA血管炎相关的肺损害的根本原因，从而从分子学角度将MPO-ANCA和PR3-ANCA两个亚型鉴别开来。6.成功建立CGRP-KO动物模型。