Do estrogen receptors in B cells and DC mediate sex bias in murine lupus?

描述（申请人提供）：系统性红斑狼疮（SLE）是一种优先影响育龄期女性（9:1）的自身免疫性疾病，表明包括性激素雌二醇在内的性别特异性因素在狼疮发病中起重要作用。狼疮小鼠模型在雌性小鼠中表现出疾病的自然早期表达和随之而来的死亡。在NZM2410小鼠中存在的Sle1和Sle3狼疮易感位点直接增加了女性疾病的外显率，这与研究表明全身雌二醇升高或暴露于雌激素环境化合物加速狼疮发展的研究一致。为了理解女性SLE优势的机制，我们需要精确地确定内源性雌激素和雌激素受体（ER）如何调节免疫细胞（如B淋巴细胞和树突状细胞（DC））的功能，这些细胞表达ER并与狼疮的发病机制有关。然而，目前研究雌激素对免疫细胞影响的模型通常涉及全身暴露于超过生理水平的雌二醇或雌激素受体的整体损失，这导致激素失衡。全身雌二醇水平升高导致造血祖细胞的严重耗竭，导致B细胞和DC的数量和表型改变。为了规避内质网配体对免疫细胞发育的这些影响，我们建议开发和使用一种新的小鼠狼疮模型，在这种模型中，内质网α的表达可能在分化的B细胞或DC中被特异性地消融。我们将使用慢病毒转基因将CD19或CD11c启动子驱动的Cre重组酶传递到狼疮易发B6。携带条件erα等位基因的Sle13双基因小鼠。这种方法将使我们能够确定与性别敏感的Sle1和Sle3位点相关的异常DC或骨髓后B细胞表型是否由内源性雌激素对B细胞或DC的直接作用介导。在目的1中，我们将确定是否升高的DC数量或过度激活的DC表型导致雌性B6中促炎细胞因子的产生。Sle13双基因小鼠是内源性雌激素直接作用于DC的结果。在目的2中，我们将确定女性B6中移行性B细胞亚群的扰动和随后的血清学耐受性丧失是否增强。Sle13双基因小鼠是内源性雌激素对承诺B细胞和/或DC直接作用的结果。这种在特定细胞类型中删除erα的慢病毒转基因策略的成功实施将建立一个通用模型，可用于研究狼疮性肾炎发展过程中erα信号在任何细胞类型中的作用。人类和小鼠免疫系统的细胞能够对雌激素、植物雌激素和用于治疗乳腺癌和骨质疏松症的药物产生反应。我们试图了解在自身免疫性疾病系统性红斑狼疮期间，雌激素如何控制免疫系统的关键调节细胞（称为树突状细胞和B细胞）的发育和功能。这一知识将有助于理解为什么自身免疫性疾病优先折磨女性。

DESCRIPTION (provided by applicant): Systemic lupus erythematosus (SLE) is an autoimmune disease that preferentially affects women (9:1) in their reproductive years, indicating that sex specific factors including the sex hormone estradiol play an important role in lupus pathogenesis. Murine models of lupus show natural earlier expression of disease and ensuing mortality in female mice. The Sle1 and Sle3 lupus susceptibility loci present in NZM2410 mice direct increased penetrance of disease in females, which is consistent with studies showing that elevation of systemic estradiol or exposure to estrogenic environmental compounds accelerate lupus development. An understanding of the mechanisms underlying the female preponderance of SLE requires that we precisely determine how endogenous estrogens and estrogen receptors (ER) regulate the function of immune cells such as B lymphocytes and dendritic cells (DC), which express ER and have been implicated in lupus pathogenesis. However, current models for the study of estrogen effects on immune cells often have involved systemic exposure to supra-physiological levels of estradiol or global loss of ER, which creates hormonal imbalances. Elevated systemic levels of estradiol result in a profound depletion of hematopoietic progenitors, leading to alterations in numbers and phenotype of B cells and DC. To circumvent these effects of ER ligands on immune cell development, we propose to develop and use a novel model of murine lupus in which ERalpha expression may be specifically ablated in differentiated B cells or DC. We will use lentiviral transgenesis to deliver Cre recombinase driven by the CD19 or CD11c promoters to lupus prone B6.Sle13 bicongenic mice bearing a conditional ERalpha allele. This approach will allow us to determine whether aberrant DC or post-bone marrow B cell phenotypes associated with the sex sensitive Sle1 and Sle3 loci are mediated by direct effects of endogenous estrogens on B cells or DC. In Aim 1, we will determine if the elevated DC numbers or hyper-activated DC phenotypes leading to pro-inflammatory cytokine production in female B6.Sle13 bicongenic mice are a result of the direct action of endogenous estrogen on DC. In Aim 2, we will determine whether perturbations in transitional B cell subsets and subsequent enhanced loss of serologic tolerance in female B6.Sle13 bicongenic mice are a result of the direct action of endogenous estrogen on committed B cells and/or DC. The successful implementation of this lentiviral transgenesis strategy to delete ERalpha in specific cell types will establish a versatile model that could be used to study the role of ERalpha signaling in any cell type during the development of lupus nephritis. PUBLIC HEALTH RELEVANCE Cells of the human and murine immune systems are capable of responding to estrogens, phytoestrogens and drugs used for treatment of breast cancer and osteoporosis. We seek to understand how estrogens control the development and function of key regulatory cells of the immune system, termed dendritic cells and B cells, during the autoimmune disease Systemic Lupus Erythematosus. This knowledge will help to understand why autoimmune diseases preferentially afflict women.