Roles of HDAC3 in epidermal Langerhans cell ontogeny and function

 描述(申请人提供)：朗格汉斯细胞(LCS)，皮肤中的树突状细胞(DC)，在皮肤中形成一个连续的免疫网络，参与过敏、感染、癌症和自身免疫性疾病的发展。然而，LCS的发育和功能所涉及的调控机制尚未完全阐明。组蛋白脱乙酰酶(HDACs)是一种通过去掉靶蛋白上的乙酰基或直接去乙酰化非组蛋白来改变染色质结构来调节基因表达的酶，代表着一种关键的表观遗传调控机制。HDAC抑制剂(HDI)在多种疾病中具有抗肿瘤和抗炎作用，其中LCS起着重要作用。然而，HDI临床疗效的潜在机制在很大程度上仍不清楚。我们最近报道，曲古抑菌素A(TSA)对第I/II类HDAC的抑制在体内外调节LC的动态平衡和功能，并调节LC中非编码miRNA的表达，而miRNAs也控制LC的发展和功能。我们的初步数据表明，LC表达所有I/II类HDAC。为了评估单个HDACs在LC发育和功能中的作用，我们建立了选择性缺失表皮LCS中HDAC3(Class I)或HDAC4(Class II)的敲除(KO)小鼠。有趣的是，LC-HDAC3KO小鼠的LC数量显著减少，而LC-HDAC4KO小鼠的LC数量没有受到影响。此外，LC-HDAC3KO小鼠的LC成熟和功能也发生了改变。因此，我们假设HDAC3是控制LC发育和功能的关键表观遗传学成分。在目标1中，我们将研究HDAC3在LC发育和动态平衡中的作用，使用LC-HDAC3KO小鼠进行出生后的动态平衡，并使用结构性CSF1R特异性HDAC3缺失小鼠(CSF1R-HDAC3)和诱导性CSF1R特异性HDAC3缺失(Csfr1.Mer-HDAC3)小鼠进行胚胎LC发育；目的2，我们将利用诱导型LC-ER.HDAC3KO小鼠来研究HDAC3在LC功能中的作用。在目标3中，我们将结合cDNA阵列、miRNA阵列和芯片序列技术，阐明HDAC3调控LC发育和功能的分子机制和信号通路。这些研究将揭示HDAC3在LC发育和功能中的表观遗传调控机制，并可能阐明HDI治疗的新机制。

 DESCRIPTION (provided by applicant): Langerhans cells (LCs), the skin residing dendritic cells (DCs), form a contiguous immune network in skin and are involved in allergy, infection, cancer, and autoimmune disease development. However, the regulatory mechanisms involved in the development and functions of LCs have not been completely elucidated. Histone deacetylases (HDACs) are enzymes that regulate gene expression by modifying chromatin structure through removal of acetyl groups from target histones or directly deacetylating non- histone proteins, and represent a key epigenetic regulatory mechanism. HDAC inhibitors (HDI) are shown to have anti-tumor and anti-inflammatory effects in a variety of diseases, in which LCs play an important role. However, the mechanisms underlying the clinical effectiveness of HDI remain largely unknown. We recently reported that the inhibition of Class I/II HDACs by Trichostatin A (TSA) regulates the homeostasis and function of LCs in vitro and in vivo and modulates the non-coding miRNA expressions in LCs, while miRNAs also control LC development and function. Our preliminary data indicate that LCs express all Class I/II HDACs. To evaluate the role of individual HDACs in LC development and function, we generated knockout (KO) mice with selective deletion of HDAC3 (Class I) or HDAC4 (Class II) in epidermal LCs. Interestingly, LC number was significantly reduced in LC-HDAC3KO mice, but unaffected in LC-HDAC4KO mice. Furthermore, LC maturation and function were altered in LC-HDAC3KO mice. Thus, we hypothesize that HDAC3 is a key epigenetic component that controls LC development and function. In Aim 1, we will investigate the roles of HDAC3 in LC development and homeostasis, using LC-HDAC3KO mice for homeostasis after birth and using constitutive Csf1r-specific HDAC3-deletion mice (Csf1r-HDAC3) and inducible Csf1r- specific HDAC3-deletion (Csfr1.Mer-HDAC3) mice for early embryonic LC development; Aim 2, we will investigate the roles of HDAC3 in LC function, using inducible LC- ER.HDAC3KO mice. In Aim 3, we will elucidate the molecular mechanisms and signaling pathways by which HDAC3 regulates LC development and function, by combining cDNA array, miRNA array and ChiP-Seq techniques. The proposed studies will uncover the epigenetic regulatory mechanisms of HDAC3 in LC development and function, and may also elucidate new mechanisms for HDI therapy.