Alpha-Actinin:Renal Pathogenicity of anti-DNA Antibodies

描述（由申请方提供）：抗双链（ds）抗体 DNA是SLE的血清学标志。虽然已经 证明抗dsDNA抗体在细胞凋亡中起关键作用。 狼疮性肾炎的发病机制，损伤的机制是不完全的 明白实验证据有力地表明，至少有一些 抗dsDNA抗体由于它们的直接交叉反应性而具有致病性 肾抗原我们最近证明了一种致病性抗dsDNA抗体 抗体（R4 A）结合至表达于细胞表面上的100 kD蛋白质， 系膜细胞系来源于狼疮倾向的MRL-lpr/lpr小鼠， 裂解物的DNA酶处理不影响结合。绑定非常 在来源于非自身免疫性肾小球疾病的系膜细胞系的裂解物中减少， 小鼠，这表明抗原表达和/或可用性在小鼠的水平， 靶器官可能是决定狼疮易感性的一个因素 肾炎将R4 A结合的100 kD蛋白鉴定为 在α-辅肌动蛋白中，R4 A与α-辅肌动蛋白的结合被Western印迹证实。 印迹、ELISA和抑制研究。高滴度抗α辅肌动蛋白 在狼疮小鼠的血清和肾脏洗脱液中发现了抗体， 肾炎和狼疮患者的血清中。 本提案的目的是研究是否与α-辅肌动蛋白交叉反应 可能是某些抗DNA抗体肾脏致病性的重要决定因素 抗体，如果α-辅肌动蛋白的表达是遗传调节的， 受性别和暴露于细胞因子的调节。我们将确定是否 抗α辅肌动蛋白抗体是致病性的，如果它们与 dsDNA，通过用α-辅肌动蛋白免疫小鼠，并研究 正常和自身免疫小鼠中的抗α-辅肌动蛋白抗体应答。的 α-辅肌动蛋白抗原展示水平差异的分子基础 将研究自身免疫和非自身免疫小鼠品系之间的差异， 年龄、性别和已知存在于狼疮肾中的细胞因子对 将测定α-辅肌动蛋白表达和抗体结合。最后我们 将确定α-辅肌动蛋白的表位， 抗双链DNA抗体，以了解抗α辅肌动蛋白的产生 抗体，并确定潜在的α-辅肌动蛋白肽在 狼疮性肾炎的治疗方法

DESCRIPTION (provided by applicant): Antibodies against double stranded (ds) DNA are a characteristic serologic hallmark of SLE. While it has been demonstrated that anti-dsDNA antibodies play a critical role in the pathogenesis of lupus nephritis, the mechanisms of injury are incompletely understood. Experimental evidence strongly suggests that at least some anti-dsDNA antibodies are pathogenic by virtue of their direct cross-reactivity with renal antigen. We recently demonstrated that a pathogenic anti-dsDNA antibody (R4A) binds to a 100 kD protein expressed on the cell surface of a mesangial cell line derived from a lupus-prone MRL-lpr/lpr mouse, and that DNAse treatment of the lysate does not affect binding. Binding was greatly diminished in lysates of a mesangial cell line derived from a non-autoimmune mouse, suggesting that antigen expression and/or availability at the level of the target organ may be a factor in determining susceptibility to lupus nephritis. Following identification of the 100 kD protein bound by R4A as alpha-actinin, the binding of R4A to alpha-actinin was confirmed by Western blot, ELISA, and inhibition studies. High titers of anti-alpha-actinin antibodies were found in the serum and kidney eluates of lupus mice with nephritis, and in the serum of lupus patients. The goals of this proposal are to study if cross-reactivity with alpha-actinin may be an important determinant of the renal pathogenicity of some anti-DNA antibodies, and if the expression of alpha-actinin is genetically regulated and modulated by gender and exposure to cytokines. We will determine if anti-alpha-actinin antibodies are pathogenic and if they cross-react with dsDNA, by immunization of mice with alpha-actinin and studying the anti-alpha-actinin antibody response in normal and autoimmune mice. The molecular basis for the differential levels of antigen display of alpha-actinin between autoimmune and non-autoimmune mouse strains will be studied, and the effects of age, gender, and cytokines known to be present in lupus kidneys on alpha-actinin expression and antibody binding will be determined. Finally, we will identify the epitopes of alpha-actinin that are recognized by pathogenic anti-dsDNA antibodies to understand the generation of anti-alpha-actinin antibodies, and determine the potential of alpha-actinin peptides in the treatment of acute lupus nephritis.