Epigenetic downregulation of the antibody and autoantibody response

描述（由申请人提供）：抗体和自身抗体反应的表观遗传下调表观遗传标记包括DNA甲基化，组蛋白修饰和microrna。正如我们所论述的，这些“相互作用”与基因程序来调节B细胞的功能，如类开关DNA重组（CSR）、体细胞超突变（SHM）和浆细胞分化，从而通知抗体反应。表观遗传失调可导致对外源性抗原（如病毒和细菌上的抗原）或自身抗原（如狼疮中的染色质、组蛋白和双链dna）的异常抗体反应。我们假设表观遗传调节剂组蛋白去乙酰化酶（HDAC）抑制剂（hdi）抑制B细胞内在功能CSR/SHM和浆细胞分化，从而减弱抗体和自身抗体反应。我们进一步认为hdi通过上调选定的microrna来抑制这些B细胞功能，包括miR-155， miR-181b和miR-361下调AID （Aicda基因，对CSR/SHM至关重要），以及miR-23b， miR-30a和miR-125下调Blimp1 （Prdm1基因，对浆细胞分化至关重要）。我们的假设独特地关注于B细胞，并得到了我们在体外纯化的人和小鼠B细胞的令人注目的数据的支持，在体内正常小鼠对T依赖性和T非依赖性抗原有反应，并通过HDI预防疾病和“治疗”狼疮易感小鼠。我们在B细胞生物学、分子CSR/SHM机制和自身免疫方面的优势，以及我们尖端的表观遗传学工具和方法，使我们能够独特地测试我们的假设。我们将：（目的1）分析hdi（丙戊酸、丁酸和SAHA）对CSR/SHM和浆细胞分化的影响，以及正常C57BL/6和Balb/c小鼠特异性t依赖性和t非依赖性抗体反应，以及狼疮易感小鼠MRL/Faslpr/lpr和B6.NZM/Sle1.Sle2自身抗体反应。Sle3老鼠;（Aim 2）利用分子生物学、生物化学和高通量/生物信息学工具，通过增强组蛋白乙酰化和microRNA“宿主基因”的转录，分析hdi介导的B细胞中miR-155、miR-181b、miR-361、miR-23b、miR-30a和miR-125b的上调，解决这些microRNA对AID和Blimp1的下调，并利用Ago HITS-CLIP构建Aicda和Prdm1 3'UTRs的microRNA体内靶向图谱；（Aim 3）证明了B细胞microRNA在介导HDI抑制抗体和自身抗体反应中的关键作用，使用三头合一的体内方法，包括构建在Aicda或Prdm1 3' utr中缺乏特异性microRNA靶向位点的新敲入小鼠、B细胞条件Dicer或Drosha KO小鼠，以及在B细胞中表达特异性miR-155、miR-181b和miR-361（靶向Aicda）和/或特异性miR-23b、miR-30a和miR-125b（靶向Prdm1）的“海绵”抑制剂的小鼠。我们的建议是高度创新和精湛的翻译。它将为表观遗传学和免疫调节提供机制见解和未来方向，包括B细胞microrna在抗体/自身抗体反应中的关键作用以及表观遗传学工具作为自身免疫的新治疗方法。

DESCRIPTION (provided by applicant): Epigenetic downregulation of the antibody and autoantibody response Epigenetic marks include DNA methylation, histone modifications and microRNAs. As we have contended, these "interact" with genetic programs to regulate B cell functions, such as class switch DNA recombination (CSR), somatic hypermutation (SHM) and plasma cell differentiation, thereby informing the antibody response. Epigenetic dysregulation can result in aberrant antibody responses to exogenous antigens, such as those on viruses and bacteria, or self-antigens, such as chromatin, histones and dsDNA in lupus. We hypothesize that the epigenetic modulators histone deacetylase (HDAC) inhibitors (HDIs) inhibit the B cell intrinsic functions CSR/SHM and plasma cell differentiation, thereby blunting antibody and autoantibody responses. We further argue that HDIs inhibit these B cell functions by upregulating selected microRNAs, including miR-155, miR-181b and miR-361 to downregulate AID (Aicda gene, critical for CSR/SHM), as well as miR-23b, miR-30a and miR-125 to downregulate Blimp1 (Prdm1 gene, critical for plasma cell differentiation). Our hypotheses uniquely focus on B cells and are supported by our compelling data using purified human and mouse B cells in vitro, and in vivo in normal mice responding to T-dependent and T- independent antigens, and prevention of disease and "treatment" of lupus-prone mice by HDI. Our strengths in B cell biology, molecular CSR/SHM mechanisms and autoimmunity, and our cutting-edge epigenetic tools and approaches make us uniquely poised to test our hypotheses. We will: (Aim 1) analyze the impact of HDIs (valproic acid, butyrate and SAHA) on CSR/SHM and plasma cell differentiation, and on specific T-dependent and T-independent antibody responses in normal C57BL/6 and Balb/c mice and autoantibody responses in lupus-prone MRL/Faslpr/lpr and B6.NZM/Sle1.Sle2.Sle3 mice; (Aim 2) use molecular biology, biochemistry and high-throughput/bioinformatics tools to analyze HDI-mediated upregulation of miR-155, miR-181b, miR-361, miR-23b, miR-30a and miR-125b in B cells through enhanced histone acetylation and transcription of the microRNA "host genes", address downregulation of AID and Blimp1 by these microRNAs, and construct microRNA in vivo targeting maps of Aicda and Prdm1 3'UTRs using Ago HITS-CLIP; (Aim 3) prove the critical role of B cell microRNAs in mediating HDI suppression of antibody and autoantibody responses using a three-prong integrated in vivo approach involving construction of new knockin mice lacking specific microRNA targeting sites in Aicda or Prdm1 3'UTR, B cell conditional Dicer or Drosha KO mice, and mice expressing "sponge" inhibitors specific for miR-155, miR-181b and miR-361 (targeting Aicda) and/or for miR-23b, miR-30a and miR-125b (targeting Prdm1) in B cells. Our proposal is highly innovative and exquisitely translational. It will provide mechanistic insights and future directions in epigenetics and immunoregulation, including the critical role of B cell microRNAs in antibody/autoantibody responses and epigenetic tools as new therapeutics in autoimmunity.