Cellular and Genetic Basis of Systemic Lupus

描述（由申请人提供）：遗传学在系统性红斑狼疮（SLE）的发病机制中起着重要作用，这是公认的。该项目的长期目标是了解这种疾病的遗传控制。在过去的几年中，我们对一种新的小鼠模型NZM2328进行了表征。该株雌雄均有循环抗核抗体（ANA）。在男性，急性肾小球肾炎（GN）是常见的，没有严重的蛋白尿。然而，女性有严重的蛋白尿，急性和慢性GN与早期死亡。在对（NZM2328XC57L/J）F1 X NZM2328的回交分析中，已经鉴定出1号染色体的一个区域控制急性和慢性肾小球肾炎（GN）。它们被命名为Agnz1和Cgnz1。此外，4号染色体上一个名为Adnz1的位点被证明与抗ana和抗dsdna抗体的产生有关。两条同源线，NZM。C57Lc1和NZM。分别用C57L/J取代NZM2328中的相关区域生成C57Lc4。NZM。与NZM相比，C57Lc1组显著降低了蛋白尿和GN。C57Lc4有严重蛋白尿和无ANA的GN。令人惊讶的是，在NZM中没有发现ANA和anti-dsDNA。提示1号染色体上的Adnz1位点也参与了ANA的产生。这些结果导致假设单独的基因控制自身抗体（ANA，抗组蛋白和抗dsdna抗体）的产生和终末器官损伤。这种竞争性更新应用主要集中在1号染色体上控制三种不同表型的遗传片段上。提出了四个具体目标：具体目标1：产生NZM。C57Lc1基因菌株和染色体内重组图谱（F1XF1）通过杂交育种精细定位了1号染色体的遗传区域，该区域包含Agnz1、Cgnz1和Adaz2，它们控制急性、慢性GN和ANA以及相关的Ab产生。这将使我们能够识别与三种表型相关的区域中的候选基因；具体目标2：鉴定一组连续重叠的基因组克隆（contigs），覆盖感兴趣的候选基因，并对这些contigs进行测序，以确定候选基因的多态性；具体目标3：确定候选基因的功能及其在形成观察到的表型中的作用；特异性目的4：通过等位基因转基因或基因敲入技术验证易感性。本研究结果可能为狼疮性肾炎的发病机制确定重要的检查点，为治疗干预提供新的靶点。

DESCRIPTION (provided by applicant): It is well established that genetics plays a major role in the pathogenesis of systemic lupus erythematosus (SLE). The long-term goal of this project is to understand the genetic control of this disease. During the past several years, we have characterized a new mouse model, NZM2328. Both males and females of this strain have circulating anti-nuclear antibodies (ANA). In the males, acute glomerulonephritis (GN) is seen frequently without severe proteinuria. However, the females have severe proteinuria, acute and chronic GN with early mortality. In a backcross analysis of (NZM2328XC57L/J)F1 X NZM2328, a region of chromosome 1 has been identified to control acute and chronic glomerulonephritis (GN). These have been designated as Agnz1 and Cgnz1. In addition, a locus designated as Adnz1 on chromosome 4 was shown to be linked to the production of anti-ANA and anti-dsDNA antibodies. Two congenic lines, NZM.C57Lc1 and NZM.C57Lc4 were generated by replacing the relevant region in NZM2328 with that of C57L/J respectively. NZM.C57Lc1 females have markedly reduced proteinuria and GN while those of NZM.C57Lc4 have severe proteinuria and GN without ANA. Surprisingly, ANA and anti-dsDNA are not seen in NZM.C57Lc1 suggesting that a locus, Adnz1 on chromosome 1 also contributes to ANA production. These results have led to the hypothesis that separate genes control autoantibody (ANA, anti- histone and anti-dsDNA antibodies) production and end organ damage. This competitive renewal application focuses on the genetic segment on chromosome 1 controlling three distinct phenotypes. Four specific aims are proposed: Specific Aim 1: To generate NZM.C57Lc1 congenic strains and a mapping panel of intrachromosomal recombinants by intercross breeding (F1XF1) to fine map the genetic region of chromosome 1, containing Agnz1, Cgnz1 and Adaz2, which control acute GN, chronic GN and ANA and related Ab production. This will enable us to identify candidate genes in the region relating to each of the three phenotypes; Specific Aim 2: To identify a set of contiguous overlapping genomic clones (contigs), which cover the candidate genes of interest and to sequence these contigs to define polymorphisms in the candidate genes; Specific Aim 3: To identify the functions of the candidate genes and their role in shaping the observed phenotypes; and Specific Aim 4: To validate susceptibility by allele transgenesis or gene knockin technology. The results of this research may identify important checkpoints for the pathogenesis of lupus nephritis, providing new targets for therapeutic intervention.