轉錄因子Phf11 和Egr1 在漿狀樹突細胞發育中的調控

Regulation of Plasmacytoid Dendritic Cell Development by Two Transcription Factors Phf11 and Egr1

翁瑞澤(Jui-Tse Weng)

指導教授 ： 李建國

國立臺灣大學/醫學院/免疫學研究所/碩士(2017年)

https://doi.org/10.6342/NTU201703101

摘要

樹突細胞對於抗原呈現以及連結先天及後天免疫十分重要。樹突細胞主要可 以分為漿狀樹突細胞以及傳統樹突細胞。兩者產生的比例有其相對性。由於擁有非 常短的生命週期，兩者皆得持續的從骨髓系統及淋巴系統的造血前驅細胞補充。先 前的研究已經知道在Flt3 配體 (Flt3 ligand, FL)的刺激下，共同淋巴前驅細胞 (common lymphoid progenitors, CLP) 和共同髓原前驅細胞(common myeloid progneitors, CMP)可以分化出漿狀樹突細胞。然而，漿狀樹突細胞發育的分子調控 機制到目前還不十分清楚。因此，在透過基因富集分析方法(GSEA)以及基因微陣 列之比較，我們篩選到一些轉錄因子在傳統樹突細胞中具有較高的表現量且從未 被報導過參與樹突細胞的發育。在利用基因靜默(knockdown)技術降低這些轉錄因 子在iHSPC 中的表現後，在FL 的刺激下，分析其漿狀樹突細胞分化的情形，我們 發現一系列的轉錄因子能降低漿狀樹突細胞的產生。其中以Egr1 和Phf11 這兩個 分子最令人感興趣。其中，Egr1 已經被報導參與在其他免疫細胞的分化。然而， 從未有研究指出Egr1 在樹突細胞的發育扮演腳色。進一步發現在iHSPC 中，Egr1 可以被FL 刺激而迅速表現並可能透過結合啟動子的方式，調控轉錄因子Id2 的表 現，進而影響樹突細胞的分化。最重要的是，分析Egr1 基因剔除鼠後發現pDC 的 比例及數量都有顯著的下降，而其他免疫細胞則不受到影響。最後，利用Egr1 基 因剔除的小鼠骨髓經FL 刺激培養後，pDC 和cDC1 的比例也有顯著的減少，證明了Egr1 的基因剔除是在細胞內部造成pDC 的分化受到影響。總結以上，Egr1 可 能在樹突細胞的發育中扮演從未被報導過的調控角色。

關鍵字

漿狀樹突細胞發育 ； 轉錄因子 ； 共同淋巴前驅細胞 ； 共同髓原前驅細胞 ； 基因富集分析方法

並列摘要

Dendritic cells (DCs) are critical for antigen presentation and can link the innate immunity and the adaptive immunity. DCs including conventional DCs (cDCs) and plasmacytoid DCs (pDCs). Because of the short life span , they are constantly replenished from hematopoietic stem and progenitor cells (HSPC). Previously, we have shown that upon stimulation with Flt3 ligand (FL), common myeloid progenitor (CMPs) and common lymphoid progenitors (CLPs) have the potential to develop pDC at steady-state. However, the molecular mechanism of DC development from these progenitors is still unclear. Therefore, through differential expression analysis and gene set enrichment analysis (GSEA), we have identified several transcription factors (TFs) that are preferentially expression in cDC versus pDC. Using knockdown technology in an immortalized HSPC (iHSPC) line and in vitro differentiation system with FL, we have analyzed the effect of RNA silencing of TF of interests on cDC and pDC development. We found several TFs that were capable of decreasing pDC potential, including early growth response 1 (Egr1) and Phf11. Egr1 is known for determining the differentiation pathway of myeloid cell precursors. However, the role of Egr1 in DC development has not been reported before. Our preliminary data showed that Egr1 was an FL- inducible gene in iHSPC. Egr1 knockdown in iHSPC decreased pDC while increased CD11b-B220double negative (DN) population in a feeder-free system. Interestingly, Egr1 may bind to the promoter of Id2, a master regulator for cDC development. Most importantly, the frequency of pDC were decreased in Egr1 knockout mice while other immune cell population including cDC were not affected. Moreover, pDC and cDC1 also were deceased daily in vitro BM culture suggesting that there is an intrinsic requirement of Egr1 for pDC development. Together, Egr1 may represent a novel TF regulating DC development.

並列關鍵字

Egr1 ； Phf11 ； Plasmacytoid Dendritic Cell Development ； Flt3 Ligand ； GSEA

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