The cold shock protein YB-1 (Y-box protein-1) in chronic T cell responses and systemic lupus erythematosus (SLE)

在拟议的研究中，将评估冷休克蛋白YB-1 （Y-box蛋白-1）在调节由慢性炎症驱动的系统性红斑狼疮（SLE）中的作用。目前尚无治愈方法。t细胞稳态的改变被认为在发病机制中起关键作用。在我们之前的工作中，我们已经确定YB-1是驱动原发性和恶性T细胞增殖和凋亡的中心分子。我们发现核YB-1是诱导增殖和存活所必需的。它的蛋白磷酸化和随后的从细胞质到细胞核的易位依赖于风险激酶。使用shRNA使YB-1失活诱导细胞周期阻滞，并且至少部分地取消了细胞存活。来自SLE患者的数据显示，T细胞激活后，CD4 T细胞中的YB-1减少上调，与细胞因子合成改变、细胞凋亡增强和细胞增殖率降低相关。此外，在狼疮样小鼠模型中，cre诱导的T细胞中YB-1的耗竭导致了高滴度的抗核自身抗体。本项目将探讨YB-1对t细胞分化的影响、分子机制及其与SLE病理的相关性。利用YB-1突变体的异位表达结合YB-1 shRNA下调内源性YB-1的表达，我们将把YB-1的区域分配到不同的信号通路上，并最终阐明它们在SLE中T细胞分化中的作用，如T细胞刺激或终末分化（凋亡）时细胞因子共表达决定的多功能性。在这方面，我们将区分核和细胞质YB-1定位对SLE患者外周血T细胞的影响，通过慢病毒转导分析其分子和功能特征。使用实验性SLE的NZB/W小鼠模型，我们将使用cd4 - cre诱导的YB-1缺失小鼠使用细胞类型特异性缺失YB-1，以确定YB-1在疾病过程中在t细胞分化中的作用。结果将全面了解YB-1在t细胞稳态和分化中的作用，以验证其选择性免疫调节SLE的选择。

In the proposed study, the role of the cold shock protein YB-1 (Y-box protein-1) will be evaluated for modulating systemic lupus erythematosus (SLE) which is driven by chronic inflammation. Currently, there is no cure available. Alterations in T-cell homeostasis have been suggested to play a key role in the pathogenesis. In our previous work, we have identified YB-1 as a central molecule to drive proliferation and apoptosis of primary and malignant T cells. We showed that nuclear YB-1 is required to induce proliferation and survival. Its protein phosphorylation and subsequent translocation from the cytoplasm into the nucleus is dependent on the Rsk kinase. Inactivation of YB-1 using shRNA induced cell cycle arrest and, at least partially, abrogated cell survival. Data from SLE patients revealed that YB-1 is reduced upregulated in CD4 T cells upon T-cell activation, correlating with altered cytokine synthesis, enhanced apoptosis, and reduced cell proliferation rates. In addition, Cre-induced depletion of YB-1 in T cells led to high titers of anti-nuclear autoantibodies in a lupus-like mouse model.In the proposed project, the impact and molecular mechanisms that YB-1 has on T-cell differentiation and its relevance for SLE pathology will be addressed. Using ectopic expression of YB-1 mutants in combination with YB-1 shRNA to down-regulate the expression of endogenous YB-1, we will assign regions of YB-1 to distinct signaling pathways and, ultimately, elucidate their contributions in the context of T-cell differentiation in SLE, such as polyfunctionality determined by cytokine coexpression upon T cell stimulation or terminal differentiation (apoptosis). In this respect, we will distinguish between the impact of nuclear and cytoplasmic YB-1 localization applied to peripheral blood T cells harvested from SLE patients by using lentiviral transduction to analyze their molecular and functional characteristics. Using the NZB/W mouse model for experimental SLE, we will use cell type-specific depletion of YB-1 using CD4-Cre-inducible YB-1-deleter mice, in order to determine YB-1´s role in T-cell differentiation in the course of the disease. Results will give comprehensive insights into the roles of YB-1 in T-cell homeostasis and differentiation to validate the option to target it for the selective immune modulation of SLE.