Protein kinase Cδ oxidation contributes to ERK inactivation in lupus T cells.
Protein kinase Cδ oxidation contributes to ERK inactivation in lupus T cells.
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DOI：
10.1002/art.34503
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发表时间：
2012-09
影响因子：
--
通讯作者：
Richardson, Bruce C.
中科院分区：
文献类型：
--
作者：
Gorelik, Gabriela J.;Yarlagadda, Sushma;Richardson, Bruce C.
来自活动性狼疮患者的CD4+ T细胞具有受损的ERK通路信号传导，其降低DNA甲基转移酶表达，导致DNA去甲基化、免疫基因过表达和自身免疫。ERK通路缺陷是由于PKCδ激活环中T505磷酸化受损所致。然而，在狼疮T细胞中阻止PKCδ T505磷酸化的机制尚不清楚。其他人已经报道了T细胞以及血清蛋白的氧化修饰，特别是硝化与狼疮疾病活动相关。我们假设硝化作用使PKCδ失活，导致狼疮T细胞中ERK通路信号转导受损。从狼疮患者和对照中纯化CD4+ T细胞，然后用PMA刺激。信号蛋白水平，硝化和磷酸化通过免疫沉淀和免疫印迹的T细胞裂解物进行定量。通过电穿孔进行转染。用过氧亚硝酸盐硝化PKCδ处理CD4+ T细胞，阻止PKCδ T505磷酸化并抑制ERK途径信号传导，与在狼疮T细胞中观察到的类似。活动性狼疮患者的硝化T细胞PKCδ水平高于对照组，这与疾病活动直接相关，抗硝基酪氨酸免疫沉淀表明，硝化PKCδ，而不是未修饰的PKCδ，对PMA刺激的T505磷酸化是难治的，类似于过氧亚硝酸盐处理的细胞中的PKCδ。氧化应激导致PKCδ硝化，从而阻止其磷酸化并导致狼疮T细胞中ERK信号转导减少。这些结果将PKCδ确定为狼疮中氧化应激和T细胞表观遗传修饰之间的联系。
CD4+ T cells from patients with active lupus have impaired ERK pathway signaling that decreases DNA methyltransferase expression, resulting in DNA demethylation, overexpression of immune genes and autoimmunity. The ERK pathway defect is due to impaired phosphorylation of T505 in the PKCδ activation loop. However, the mechanisms preventing PKCδ T505 phosphorylation in lupus T cells are unknown. Others have reported that oxidative modifications, and nitration in particular, of T cells as well as serum proteins correlate with lupus disease activity. We hypothesized that nitration inactivates PKCδ, contributing to impaired ERK pathway signaling in lupus T cells. CD4+ T cells were purified from lupus patients and controls then stimulated with PMA. Signaling protein levels, nitration and phosphorylation were quantitated by immunoprecipitation and immunoblotting of T cell lysates. Transfections were performed by electroporation. Treating CD4+ T cells with peroxynitrite nitrated PKCδ, preventing PKCδ T505 phosphorylation and inhibiting ERK pathway signaling similar to that observed in lupus T cells. Patients with active lupus had higher nitrated T cell PKCδ levels than controls which correlated directly with disease activity, and anti-nitrotyrosine immunoprecipitations demonstrated that nitrated PKCδ, but not unmodified PKCδ, was refractory to PMA stimulated T505 phosphorylation, similar to PKCδ in peroxynitrite treated cells. Oxidative stress causes PKCδ nitration, which prevents its phosphorylation and contributes to the decreased ERK signaling in lupus T cells. These results identify PKCδ as a link between oxidative stress and the T cell epigenetic modifications in lupus.
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影响因子：
12.8
作者：
Hewagama A;Richardson B
通讯作者：
Richardson B
DOI：
10.1016/j.bbrc.2004.10.102
发表时间：
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作者：
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作者：
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