Elucidating IKK1 function in germinal center B cell differentiation

描述（由申请人提供）：NF-κ B信号传导受由IKK 1、IKK 2和NEMO组成的IkB激酶复合物调节。然而，最近的研究表明IKK 1和IKK 2具有很大的不同功能。在本研究中，我们将确定IKK 1在GC B细胞中的内在功能。我们最近报道了表达不能被NIK磷酸化的突变IKK 1分子（IKK 1AA）的B细胞不形成GC。在此，我们将通过检测IKK 1在GC中通过CD 40/BAFF-R/TNF-R2信号传导和T细胞共刺激的依赖性功能来确定这一发现的基础。我们还将使用免疫组织化学方法原位评估IKK 1通路的激活。为了补充这些研究，将产生表达条件IKK 1 flox/flox等位基因的小鼠，以与诱导型B细胞特异性Cre表达小鼠杂交，从而使我们能够在GC反应之前和期间/之后鉴定IKK 1依赖性B细胞功能。这些小鼠将与携带突变条件IKK 1等位基因的小鼠杂交，以探测IKK 1的结构域特异性功能。总之，拟议的研究将提供明确的机制深入了解IKK 1在体内的功能。 公共卫生相关性：老年中心是感染或免疫后在次级淋巴组织中形成的微环境。正是在这里，选择B淋巴细胞作为高亲和力记忆B细胞或抗体产生细胞。因此，了解引导生发中心B细胞发育的分子线索对于了解体液免疫的基础至关重要。

DESCRIPTION (provided by applicant): NF-kB signaling is regulated by the IkB kinase complex, consisting of IKK1, IKK2 and NEMO. However, recent studies have shown that IKK1 and IKK2 have largely distinct functions. In the proposed work, we will determine the intrinsic functions of IKK1 in GC B cells. We have recently reported that B cells expressing a mutant IKK1 molecule that cannot be phosphorylated by NIK (IKK1AA) do not form GCs. Herein we will determine the basis for this finding by examining IKK1- dependent functions in the GC via CD40/BAFF-R/TNF-R2 signaling and T cell costimulation. We will also assess activation of the IKK1 pathway in situ using immunohistochemical approaches. To complement these studies, mice will be generated expressing conditional IKK1flox/flox alleles to intercross with inducible B cell-specific Cre-expressing mice, thus allowing us to identify IKK1-dependent B cell functions prior to and during/after the GC reaction. These mice will be intercrossed with mice bearing mutant conditional IKK1 alleles to probe domain-specific functions of IKK1. Together, the proposed studies will provide definitive mechanistic insight into IKK1 function in vivo. PUBLIC HEALTH RELEVANCE: Germinal centers are microenvironments that form in the secondary lymphoid tissues following infection or immunization. It is here where B lymphocytes are selected to be high-affinity memory B cells or antibody-producing cells. Thus, understanding the molecular cues that guide germinal center B cell development is critical to understanding the basis of humoral immunity.