Nuclear receptors: action, functions, and roles in disea

核受体：在疾病中的作用、功能和作用

• 批准号: 7327214
• 负责人: Anton M Jetten
• 金额: --
• 依托单位: NATIONAL INSTITUTE OF ENVIRONMENTAL HEALTH SCIENCES
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/7327214
• 关键词: Nuclear; receptors; action; functions; roles

I. RORgamma: The retinoid-related orphan receptor g (RORg) is a member of the nuclear receptor superfamily. To identify the physiological functions of RORg, mice deficient in RORg function were generated by targeted disruption. RORg -/- mice lack peripheral and mesenteric lymph nodes and Peyer?s patches indicating that RORg expression is indispensable for lymph node organogenesis. Although the spleen is enlarged, its architecture is normal. The number of peripheral blood CD3+ and CD4+ lymphocytes is reduced 6- and 10-fold, respectively, while the number of circulating B cells is normal. The thymus of RORg-/- mice contains 74.4+ 8.9% fewer thymocytes than that of wt mice. Flow cytometric analysis showed a decrease in the CD4+CD8+ subpopulation. TUNEL staining demonstrated a four-fold increase in apoptotic cells in the cortex of the thymus of RORg-/- mice. This was supported by the observed increase in annexin V-positive cells. RORg-/- thymocytes placed in culture exhibit a dramatic increase in the rate of "spontaneous" apoptosis. This increase is largely associated with CD4+CD8+ thymocytes and may at least in part be related to the greatly reduced level of expression of the anti-apoptotic gene Bcl-XL. Flow cytometric analysis demonstrated a six-fold rise in the percentage of cells in the S phase of the cell cycle among thymocytes from RORg-/- mice. Our observations indicate that RORg is essential for lymphoid organogenesis and plays an important regulatory role in thymopoiesis. Recently, we found that RORg-/- mice are highly susceptible to the development of T-cells lymphomas. Altered expression of ROR leads to deregulation of the differentiation of thymocytes, increased proliferation of double negative thymocytes, which in turn increases the frequency of tumor formation. Recent studies have demonstrated that ROR receptors play a regulatory role in various inflammatory respeonses. RORa mice are more susceptible to endotoxin-induced inflammation. Microarray analysis demonstarted a role for RORs in steroid and drug metabolism. II. TAK1: The nuclear orphan receptor TAK1 functions as a positive as well as a negative regulator of transcription; however little is know about factors mediating its activity. Yeast two-hybrid analysis using the ligand binding domain of TAK1 as bait identified a novel TAK1-interacting protein, referred to as TIP27. TIP27 is a 27 kD nuclear protein that contains two zinc finger motifs. Confocal microscopy using TIP27 and several deletion mutants showed that TIP27 localized to the nucleus and that the carboxyl terminus containing a putative nuclear localization signal is important for its nuclear localization. TIP27 mRNA is expressed in several adult tissues but is most highly expressed in testis where it is induced at a specific stage of spermatogenesis. Mammalian two-hybrid analysis showed that TIP27 interacts specifically with TAK1 and not with several other nuclear receptors tested. Deletion mutation analysis determined that the region between Asp39 and Lys79 of TIP27, referred to as TAK1-interaction domain (TID), is critical for its interaction with TAK1. Moreover, it demonstrated that the TAK1-LBD from H3 till the carboxyl terminus is required for optimal interaction with TIP27. Pull-down assays demonstrated that TIP27 physically interacts with TAK1 and supported the importance of the TID. TIP27 is a strong repressor of DR1-dependent transcriptional activation by TAK1. This repression does not involve inhibition of TAK1 homodimerization or DR1 binding but appears to due to an inhibition of the recruitment of co-activators. Our studies indicate that TIP27 is an effective repressor of transcriptional activation by TAK1 and, therefore, may play a critical role in the regulation of several physiological functions by TAK1. Generation of TAK1 knockout mice revealed several phenotypes that are currently being investigated. The nuclear protein RAP80 was shown to interact with the estrogen receptor alpha in an agonist dependent manner. In addition, RAP80 was implicated in DNA repair. The role of RAP80 in tumorigenesis is being investigated.

类维甲酸相关孤儿受体g （RORg）是核受体超家族的一员。为了确定RORg的生理功能，通过靶向破坏产生了RORg功能缺失的小鼠。RORg -/-小鼠缺乏外周和肠系膜淋巴结和Peyer？这表明RORg的表达对于淋巴结器官发生是不可或缺的。脾脏虽肿大，但其结构正常。外周血CD3+和CD4+淋巴细胞数量分别减少6倍和10倍，而循环B细胞数量正常。RORg-/-小鼠胸腺中胸腺细胞比wt小鼠减少74.4+ 8.9%。流式细胞分析显示CD4+CD8+亚群减少。TUNEL染色显示，RORg-/-小鼠胸腺皮层凋亡细胞增加4倍。这被观察到的膜联蛋白v阳性细胞的增加所支持。RORg-/-胸腺细胞在培养中表现出“自发”凋亡率的急剧增加。这种增加在很大程度上与CD4+CD8+胸腺细胞有关，至少部分可能与抗凋亡基因Bcl-XL的表达水平大幅降低有关。流式细胞分析显示，RORg-/-小鼠胸腺细胞处于细胞周期S期的细胞百分比增加了6倍。我们的观察结果表明，RORg对淋巴器官发生至关重要，并在胸腺生成中发挥重要的调节作用。最近，我们发现RORg-/-小鼠对t细胞淋巴瘤的发展非常敏感。ROR表达的改变导致胸腺细胞分化的失调，双阴性胸腺细胞的增殖增加，从而增加肿瘤形成的频率。最近的研究表明，ROR受体在多种炎症反应中起调节作用。RORa小鼠更容易受到内毒素引起的炎症。微阵列分析证实了RORs在类固醇和药物代谢中的作用。