EBV epigenetically suppresses the B cell-to-plasma cell differentiation pathway while establishing long-term latency.
EBV epigenetically suppresses the B cell-to-plasma cell differentiation pathway while establishing long-term latency.
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DOI：
10.1371/journal.pbio.2001992
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发表时间：
2017-08
期刊：
影响因子：
9.8
通讯作者：
Allday MJ
中科院分区：
文献类型：
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作者：
Styles CT;Bazot Q;Parker GA;White RE;Paschos K;Allday MJ
被EB病毒（EBV）感染的成熟人B细胞被激活、生长和增殖。如果细胞被离体感染，则它们被转化成持续增殖的淋巴母细胞样细胞系（LCL），其携带EBV DNA作为染色体外附加体，表达9种潜伏相关EBV蛋白，并且表型类似于抗原活化的B母细胞。体内相似的B-母细胞可以分化成为记忆B细胞（MBC），其中建立了EBV持久性。三种相关的潜伏相关病毒蛋白EBNA 3A、EBNA 3B和EBNA 3C是调节多种细胞基因的转录因子。EBNA 3B不是建立LCL所必需的，但EBNA 3A和EBNA 3C是维持增殖所必需的，部分是通过抑制肿瘤抑制基因的表达。在这里，我们表明，使用EB病毒重组体，其中EBNA 3A和EBNA 3C可以有条件地灭活或使用病毒完全缺乏EBNA 3基因座，即在一个阶段的快速增殖后，感染的原代B细胞表达与浆细胞（PC）分化相关的因子水平升高。这些包括细胞周期蛋白依赖性激酶抑制剂（CDKI）p18 INK 4c、PC分化B淋巴细胞诱导成熟蛋白-1（BIMP-1）的主要转录调节因子以及细胞表面抗原CD 38和CD 138/Syndecan-1。染色质免疫沉淀测序（ChIP-seq）和染色质免疫沉淀定量PCR（ChIP-qPCR）表明，在LCL中，CDKN 2C（p18 INK 4c）和PRDM 1（BIMP-1）转录的抑制是由于EBNA 3A和EBNA 3C与这些位点的调控元件直接结合，产生稳定的重编程。与EBNA 3A和/或EBNA 3C的结合导致不可逆的表观遗传学变化一致，细胞在感染后<12天被定型为B-母细胞命运，并且不能通过灭活EBNA 3A和EBNA 3C来去抑制p18 INK 4c或BLIMP-1-在新感染的细胞或条件性LCL中。在体外，用缺乏功能性EBNA 3A和EBNA 3C的EBV感染后约20天，细胞发展成PC样表型。总之，这些数据表明，EBNA 3A和EBNA 3C已经进化到防止分化为PC感染后的EBV，从而有利于长期潜伏期MBC和无症状的持久性。EB病毒（EBV）感染可导致与其在人类中的主要靶点（成熟B细胞）相关的几种类型的癌症。此外，EBV是迄今为止鉴定的最有效的转化剂之一，其产生体外“永生”B淋巴母细胞样细胞系（LCL），具有出色的可靠性。然而，EB病毒与其天然宿主之间的近共生关系（>95%的成年人无症状感染）提供了一个强有力的论据，即这种γ-疱疹病毒最初并没有进化成一种有害的致肿瘤病毒。与此相一致，我们在这里显示，2个潜在的致癌病毒蛋白（EBNA 3A和EBNA 3C）已演变为不促进致癌进展，但阻止浆细胞分化的EBV激活的B细胞。具体而言，它们的作用是中断驱动活化的B细胞变成终末分化的静止浆细胞的基因调控网络，从而允许病毒感染的B细胞持续再生。EBNA 3A和EBNA 3C通过表观遗传学抑制分化途径所必需的细胞基因的表达来实现这一点;这些基因包括细胞周期蛋白依赖性激酶抑制剂p18 INK 4c和转录因子BLIMP-1。这有利于在长寿记忆B细胞中建立EBV潜伏期，因此有助于在人群中维持普遍存在的、通常无症状的感染。
Mature human B cells infected by Epstein-Barr virus (EBV) become activated, grow, and proliferate. If the cells are infected ex vivo, they are transformed into continuously proliferating lymphoblastoid cell lines (LCLs) that carry EBV DNA as extra-chromosomal episomes, express 9 latency-associated EBV proteins, and phenotypically resemble antigen-activated B-blasts. In vivo similar B-blasts can differentiate to become memory B cells (MBC), in which EBV persistence is established. Three related latency-associated viral proteins EBNA3A, EBNA3B, and EBNA3C are transcription factors that regulate a multitude of cellular genes. EBNA3B is not necessary to establish LCLs, but EBNA3A and EBNA3C are required to sustain proliferation, in part, by repressing the expression of tumour suppressor genes. Here we show, using EBV-recombinants in which both EBNA3A and EBNA3C can be conditionally inactivated or using virus completely lacking the EBNA3 gene locus, that—after a phase of rapid proliferation—infected primary B cells express elevated levels of factors associated with plasma cell (PC) differentiation. These include the cyclin-dependent kinase inhibitor (CDKI) p18INK4c, the master transcriptional regulator of PC differentiation B lymphocyte-induced maturation protein-1 (BLIMP-1), and the cell surface antigens CD38 and CD138/Syndecan-1. Chromatin immunoprecipitation sequencing (ChIP-seq) and chromatin immunoprecipitation quantitative PCR (ChIP-qPCR) indicate that in LCLs inhibition of CDKN2C (p18INK4c) and PRDM1 (BLIMP-1) transcription results from direct binding of EBNA3A and EBNA3C to regulatory elements at these loci, producing stable reprogramming. Consistent with the binding of EBNA3A and/or EBNA3C leading to irreversible epigenetic changes, cells become committed to a B-blast fate <12 days post-infection and are unable to de-repress p18INK4c or BLIMP-1—in either newly infected cells or conditional LCLs—by inactivating EBNA3A and EBNA3C. In vitro, about 20 days after infection with EBV lacking functional EBNA3A and EBNA3C, cells develop a PC-like phenotype. Together, these data suggest that EBNA3A and EBNA3C have evolved to prevent differentiation to PCs after infection by EBV, thus favouring long-term latency in MBC and asymptomatic persistence. Epstein-Barr virus (EBV) infection can cause several types of cancer associated with its major target in humans, the mature B cell. Furthermore, EBV is one of the most potent transforming agents ever identified, producing—in vitro—‘immortal’ B lymphoblastoid cell lines (LCLs) with outstanding reliability. However, the near-symbiotic relationship between EBV and its natural host (>95% of human adults are asymptomatically infected) provides a powerful argument that this gamma-herpesvirus did not primarily evolve to be a harmful tumour-causing virus. Consistent with this, we show here that 2 of the potentially oncogenic viral proteins (EBNA3A and EBNA3C) have evolved not to facilitate oncogenic progression but to block plasma cell differentiation in EBV-activated B cells. Specifically, they act to interrupt the gene regulation network that drives activated B cells to become terminally differentiated, quiescent plasma cells, thus allowing for sustained regeneration of virally infected B cells. EBNA3A and EBNA3C achieve this by epigenetically inhibiting expression of cellular genes essential for the differentiation pathway; these include the cyclin-dependent kinase inhibitor p18INK4c and the transcription factor BLIMP-1. This favours the establishment of EBV latency in long-lived memory B cells and therefore helps maintain a ubiquitous, generally asymptomatic infection in human populations.
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影响因子：
--
作者：
Liu S;Chan HL;Bai F;Ma J;Scott A;Robbins DJ;Capobianco AJ;Zhu P;Pei XH
通讯作者：
Pei XH
DOI：
10.1084/jem.20130323
发表时间：
2013-11-18
期刊：
The Journal of experimental medicine
影响因子：
--
作者：
Deenick EK;Avery DT;Chan A;Berglund LJ;Ives ML;Moens L;Stoddard JL;Bustamante J;Boisson-Dupuis S;Tsumura M;Kobayashi M;Arkwright PD;Averbuch D;Engelhard D;Roesler J;Peake J;Wong M;Adelstein S;Choo S;Smart JM;French MA;Fulcher DA;Cook MC;Picard C;Durandy A;Klein C;Holland SM;Uzel G;Casanova JL;Ma CS;Tangye SG
通讯作者：
Tangye SG
影响因子：
6.7
作者：
Kalchschmidt JS;Gillman AC;Paschos K;Bazot Q;Kempkes B;Allday MJ
通讯作者：
Allday MJ
影响因子：
6.7
作者：
McClellan MJ;Wood CD;Ojeniyi O;Cooper TJ;Kanhere A;Arvey A;Webb HM;Palermo RD;Harth-Hertle ML;Kempkes B;Jenner RG;West MJ
通讯作者：
West MJ
影响因子：
6.7
作者：
Bazot Q;Paschos K;Skalska L;Kalchschmidt JS;Parker GA;Allday MJ
通讯作者：
Allday MJ