Genetic and Environmental Modifiers Of Autoimmune Disease

在我们过去的研究中，我们发现了几个狼疮易感基因，它们本身或通过与各种其他遗传因素相互作用，改变了自身免疫性疾病的诱导和进展。我们先前确定IgG受体Fc γ RIIB缺陷的小鼠产生自发的抗核抗体和致命的肾小球肾炎。在Fc γ RIIB缺陷小鼠模型中，对狼疮的其他遗传修饰因子的表征使我们能够确定Tlr 7基因的单纯重复足以加重自身免疫性疾病。 我们发现，使用转基因过表达的TLR 7，TLR 7是必不可少的调节自身免疫和树突状细胞的稳态。这些小鼠提供了一个很好的例子，说明控制先天受体的表达是多么重要。 这些研究提供了一个理论框架，其中抗病毒先天反应，当没有适当的调节，可导致自身反应性和致命的炎症性疾病。 在我们对各种狼疮鼠模型的分析中，我们检测到一种不常见的亚群（鉴定为NK1.1+ CD 11 c + CD 122 +MHC-II+）的频率增加。 这些细胞与NK细胞谱系和先前描述为IKDC的细胞具有共同的特征：（1）它们依赖于IL 15并表达E4 BP 4;（2）它们具有细胞毒性并在活化后产生I型和II型干扰素;（3）它们是通过MHC-II表达和交叉呈递至⑶ 8 ε的有效抗原呈递细胞。我们发现这些非典型NK细胞对TLR刺激有反应，因此在具有高拷贝数Tlr 7基因的小鼠中最丰富。通过体内BrdU掺入评估，它们具有高度增殖性。 在过继转移实验中，它们持续大量存在数月，并保持其表面标记特征，表明该群体在发育上是稳定的。对mRNA和microRNA的基因表达分析显示了一种修改的细胞周期程序，其中各种miR 15/16家族成员上调，推测是由于生长因子、Ras和E2 F活性水平升高介导的增殖信号。 另一方面，在这些细胞中miR 150、miR 181和miR 744的低表达意味着它们的分化能力降低。这些结果表明，经历TLR刺激的NK谱系细胞可能会开启增殖程序，从而损害其完全分化为成熟NK细胞。 这些细胞的表征发表在《免疫学杂志》上（Voynova et al. 2015） 此外，我们发现，从SLE易感小鼠脾脏中纯化的非典型NK（鉴定为NK1.1+ CD 11 c + CD 122 +MHC-II+）在转移至WT小鼠时以IFN-I和CD 40 L依赖性方式诱导持续性自身免疫性疾病。 将4x 106个NK1.1+细胞从TLR 7 tg单次转移到WT中诱导血清中炎性细胞因子的2周长的波，T细胞活化和滤泡辅助细胞在随后的几个月中持续增加，以及树突状细胞、单核细胞和粒细胞的进行性扩增。此外，IL 15缺乏，这阻碍了NK细胞的发展，改善了TLR 7 tg小鼠的自身免疫病理学。这些结果表明，NK谱系的细胞可以发育成细胞因子产生/抗原呈递细胞，其影响全身性自身免疫性疾病的引发和进展。 显示通过转移非典型NK细胞诱导疾病的实验在The Journal of Immunology的前沿出版物中报道（Voynova et al，2015）。 我们期望这些研究将有助于剖析自身免疫性病理学的要求，并将解决病原体感染在自身免疫性疾病总发病率中的作用。新发现的细胞群可能会发现潜在的疾病标志物，并为改变狼疮或其他自身免疫性疾病中正在进行的疾病提供新的途径。 此外，我们与LMVR，NIAID的Su小组合作，发现了新的I型干扰素相关途径，这些途径是在感染某些疟原虫株时诱导的。 我们的小组使用从跨物种（小鼠/疟原虫）遗传筛选阵列产生的基因列表进行了信号传导潜力的系统测试。 新的干扰素相关途径被发现，目前正在调查中。 这项研究于2015年发表在Cell Reports杂志上。

In our past studies we uncovered several lupus susceptibility genes that, either by themselves or by interacting with a variety of other genetic factors, modify both the induction and progression of autoimmune disease. We previously determined that mice deficient in the IgG receptor FcgammaRIIB develop spontaneous anti-nuclear antibodies and fatal glomerulonephritis. Characterization of other genetic modifiers of lupus in the FcgammaRIIB-deficient mouse model allowed us to determine that a mere duplication of the Tlr7 gene is sufficient to agravate autoimmune disease. We showed, using transgenic overexpression of TLR7, that TLR7 is essential to regulate autoimmunity and dendritic cell homeostasis. These mice provide a prime example of how important it is to control the expression of innate receptors. These studies provide a theoretical framework in which anti-viral innate responses, when not properly regulated, can result in autoreactivity and lethal inflammatory disease. In our analysis of our various murine models of lupus, we detected increased frequency of an uncommon subset identified as NK1.1+CD11c+CD122+MHC-II+. These cells share characteristics with the NK cell lineage and with cells previously described as IKDCs: (1) they depend on IL15 and express E4BP4 (2) they are cytotoxic and produce type I and type II interferon upon activation; (3) they are efficient antigen presenting cells both through MHC-II expression and in cross-presentation to CD8s. We showed that these atypical NK cells were responsive to TLR stimulation and thus are most abundant in mice with high copy number of the Tlr7 gene. They were highly proliferative as assessed by in vivo BrdU incorporation. In adoptive transfer experiments they persisted in high numbers for months and maintained their surface marker profile, indicating that this population was developmentally stable. Gene expression analyses on both mRNA and microRNAs showed a modified cell cycle program in which various miR15/16 family members were upregulated, presumably as a consequence of the proliferative signal mediated by the increased level of growth factors, Ras and E2F activity. On the other hand, low expression of miR150, miR181 and miR744 in these cells implied a reduction in their differentiation capacity. These results suggest that cells of the NK lineage that undergo TLR stimulation might turn on a proliferative program in detriment of their full differentiation into mature NK cells. Characterization of these cells was published in the Journal of Immunology (Voynova et al. 2015) Additionally, we showed that atypical NKs purified from spleens of SLE-prone mice, and identified as NK1.1+CD11c+CD122+MHC-II+, induced persistent autoimmune disease in an IFN-I and CD40L-dependent manner when transferred to WT mice. A single transfer of 4x106 NK1.1+ cells from TLR7tg into WT induces a 2-week-long wave of inflammatory cytokines in the serum, a sustained increase in T cell activation and follicular helper cells for the following months, and a progressive expansion of dendritic cells, monocytes and granulocytes. Furthermore IL15 deficiency, which impedes development of NK cells, ameliorated the autoimmune pathology of TLR7tg mice. These results suggested that cells of the NK lineage can develop into cytokine producing/antigen-presenting cells that affect the priming and progression of systemic autoimmune disease. Experiments showing the induction of disease by transfer of atypical NK cells were reported in a Cutting Edge publication by The Journal of Immunology (Voynova et al, 2015). We expect that these studies will help dissect the requirements for autoimmune pathology and will address the effect of pathogen infections in overall incidence of autoimmune disease. Newly discovered cell populations will possibly uncover potential markers of disease and suggest new routes for modifying ongoing disease in lupus or other autoimmune diseases. In addition, we collaborated with the Su group at LMVR, NIAID to uncover new type-I interferon related pathways that are induced in infection with certain strains of the Plasmodium parasite. Our group performed a methodical testing of signaling potential using a list of genes generated from a cross-species (Mouse/Plasmodium) genetic screen array. Novel interferon-related pathways were uncovered that are now under investigation. This research was published in the journal Cell Reports in 2015.