Regulation of plasma cell homeostasis and antibody secretion through modulation of autophagy and endoplasmic reticulum stress by Trk-fused-gene (TFG)

Trk 融合基因 (TFG) 通过调节自噬和内质网应激来调节浆细胞稳态和抗体分泌

• 批准号: 503852185
• 负责人: Professor Dr. Dirk Mielenz
• 金额: --
• 依托单位: Abteilung für Molekulare Immunologie /MED III
• 依托单位国家: 德国
• 项目类别: Research Grants
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/503852185?language=en
• 关键词: Regulation; plasma; cell; homeostasis; antibody

Antibodies (Ab) are secreted by plasma blasts and plasma cells that are generated in secondary lymphatic organs. Endoplasmic reticulum (ER) quality control and autophagy are essential for plasma cell differentiation and maintenance, Ab assembly and secretion. We have previously demonstrated that TFG (Tropomyosin receptor kinase fused gene), a scaffold protein that is up-regulated in plasma cells, prevents ER stress and supports autophagy flux in CH12 B cells. Proteomic analyses of CH12 B cells suggest a role for TFG in the regulation of intracellular transport, mitochondrial metabolism and JCHAIN abundance. We therefore hypothesize that TFG is important for plasma cell homeostasis in vivo. To test this hypothesis, we have generated mice carrying a floxed tfg allele (tfgfl/fl) that were crossed to mb1-Cre mice (TFG_BKO). Preliminary data from non-immunized tfgB mice show reduced plasma cell numbers. Serum IgM and IgG were reduced while IgA was not. However, there is no dimeric serum IgA in tfgB mice in steady state and IgA in feces is strongly diminished. In this project we will extend these preliminary data by eliciting T cell dependent and independent immunity and explore the IgM, IgG and IgA responses in TFG_BKO mice. Owing to the effects of TFG on JCHAIN and IgA we will specifically analyze B cell and plasma cell subsets in spleen, bone marrow as well as gut associated lymphoid tissue (GALT) in depth, along with resolution of GALT structure. To explore the TFG-dependent JCHAIN amount, JCHAIN will be quantified in plasma cell subsets of TFG_BKO mice in steady state, after immunization and in overexpression experiments. Furthermore, we will resolve Ig assembly and homeostasis. The effect of tfg-deletion on ER homeostasis, autophagy and metabolic signaling will be determined in primary activated B cells from tfgB mice. Elucidation of the role of TFG in B cells and plasma cells will help to understand the cell biology of plasma cells that is required to support antibody synthesis and humoral immunity.

抗体（Ab）由次级淋巴器官中产生的浆母细胞和浆细胞分泌。内质网（ER）的质量控制和自噬是浆细胞分化和维持、抗体组装和分泌所必需的。我们以前已经证明，TFG（原肌球蛋白受体激酶融合基因），一种支架蛋白，在浆细胞中上调，防止ER应激，并支持自噬流量在CH 12 B细胞。CH 12 B细胞的蛋白质组学分析表明TFG在调节细胞内转运、线粒体代谢和JCHAIN丰度中的作用。因此，我们假设TFG对体内浆细胞稳态很重要。为了检验这一假设，我们产生了携带floxed tfg等位基因（tfgfl/fl）的小鼠，将其与mb 1-Cre小鼠（TFG_BKO）杂交。来自未免疫的tfg β B小鼠的初步数据显示浆细胞数量减少。血清IgM和IgG降低，而伊加不降低。然而，在稳态的tfg β B小鼠中没有二聚体血清伊加，并且粪便中的伊加强烈减少。在本项目中，我们将通过引发T细胞依赖性和非依赖性免疫来扩展这些初步数据，并探索TFG_BKO小鼠中的IgM、IgG和伊加应答。由于TFG对JCHAIN和伊加的影响，我们将具体分析脾脏、骨髓以及肠道相关淋巴组织（GALT）中的B细胞和浆细胞亚群，沿着GALT结构的解析。为了探索TFG依赖性JCHAIN量，将在稳态、免疫后和过表达实验中在TFG_BKO小鼠的浆细胞亚群中定量JCHAIN。此外，我们将解决IG组装和稳态。将在来自tfg β B小鼠的原代活化B细胞中确定tfg缺失对ER稳态、自噬和代谢信号传导的影响。阐明TFG在B细胞和浆细胞中的作用将有助于理解支持抗体合成和体液免疫所需的浆细胞的细胞生物学。