長鏈非編碼RNA每個月都有幾十篇高分文章見刊，機(jī)制也是多種多樣，咱們號上一期總結(jié)了5篇高分文章的高分套路，有些同學(xué)意猶未盡，今天小能手再給大家來5篇，定期給大家更新高分文章的機(jī)制研究套路，也方便大家找思路寫本子做實驗。

1. Long noncoding RNA MALAT1 releases epigenetic silencing of HIV-1 replication by displacing the polycomb repressive complex 2 from binding to the LTR promoter.

Nucleic Acids Res11.5611區(qū). 2019 Apr 8

不用多說，MALAT1這個最知名的lncRNA了，從我第一次接觸非編碼RNA的概念時，就知道MALAT1了。

分子機(jī)制：這里面有一個正反饋回路機(jī)制。作者通過RNA-seq發(fā)現(xiàn)被HIV-1病毒感染的CD4+ T免疫細(xì)胞中MALAT1上調(diào)表達(dá)，接下來的細(xì)胞實驗發(fā)現(xiàn)，過表達(dá)以及敲減（CRISPR技術(shù)）后證明，MALAT1起到促進(jìn)HIV-1感染細(xì)胞的病毒的復(fù)制，以及相關(guān)HIV-1 LTR先關(guān)驅(qū)動基因的表達(dá)。機(jī)制上：MALAT1通過與PRC2蛋白復(fù)合物的寫作，從HIV-1 LTR啟動子區(qū)域上解離了甲基化啟動蛋白EZH2，從而去除H3K27的組蛋白甲基化修飾。而HIV-1的活躍，又可促進(jìn)MALAT1的表達(dá)，形成正反饋回路機(jī)制。

基金中正反饋回路相關(guān)的課題

摘要：In HIV-1 infected CD4+ T cells, we performed RNA-Sequencing (RNA-Seq) analysis and discovered an up-regulation of MALAT1 (metastasis-associated lung adenocarcinoma transcript 1). we found that MALAT1 promoted HIV-1 transcription and infection, as its knockdown by CRISPR/Cas9 markedly reduced the HIV-1 long terminal repeat (LTR)-driven gene transcription and viral replication. Mechanistically, through an association with chromatin modulator polycomb repressive complex 2 (PRC2), MALAT1 detached the core component enhancer of zeste homolog 2 (EZH2) from binding with HIV-1 LTR promoter, and thus removed PRC2 complex-mediated methylation of histone H3 on lysine 27 (H3K27me3) and relieved epigenetic silencing of HIV-1 transcription. Moreover, the reactivation of HIV-1 stimulated with latency reversal agents (LRAs) induced MALAT1 expression in latently infected cells. 

（最知名的lncRNA，MALAT-1的發(fā)現(xiàn)：2003年，Ji等從初期非小細(xì)胞肺癌患者的腫瘤細(xì)胞中篩選出數(shù)個差異表達(dá)基因，其中包括含一個與肺癌轉(zhuǎn)移和預(yù)后相關(guān)的未知轉(zhuǎn)錄物，采用RACE法擴(kuò)增到一個長約940nt的片段，經(jīng)檢索比對，該片段定位于人染色體11q13，屬于長約8.7kb的a基因。Ji等根據(jù)其與NSCLC發(fā)生發(fā)展的關(guān)系，將a基因轉(zhuǎn)錄物重命名為肺癌轉(zhuǎn)移相關(guān)轉(zhuǎn)錄本1（MALAT-1），后來也被稱作NEAT2。MALAT-1缺乏有意義的開放性編碼框，在體外無法翻譯蛋白質(zhì)，屬長鏈非編碼RNA（lncRNA）。MALAT-1是第一個與肺癌疾病相關(guān)聯(lián)的長鏈非編碼RNA。10多年前發(fā)現(xiàn)關(guān)于MALAT-1的大量數(shù)據(jù)積累，包括MALAT-1與其他癌癥細(xì)胞或疾病的關(guān)聯(lián)、對其生物合成的見解、與其他細(xì)胞的相互作用及分子機(jī)制等。）

2.The lncRNA Neat1 promotes activation of inflammasomes in macrophages.

Nat Commun12.3532區(qū). 2019 Apr 2

分子機(jī)制：已知炎癥小體在機(jī)體固有免疫發(fā)揮重要作用。本文中l(wèi)ncRNA NEAT1可在巨噬細(xì)胞中激活數(shù)種炎癥小體，包括NLRP3, NLRC4, AIM2炎癥小體。NEAT1可潛伏在paraspeckle小體中，在受到炎癥小體刺激信號時，從paraspeckle小體中釋放解離，游離到細(xì)胞質(zhì)中，NEAT1通過特異性吸附提升caspase-1的穩(wěn)定性，進(jìn)而增加了IL-1β的釋放，促進(jìn)細(xì)胞焦亡的發(fā)生。

（paraspeckle：細(xì)胞生物學(xué)中，paraspeckle小體指細(xì)胞核染色質(zhì)間隙中的一種不規(guī)則亞結(jié)構(gòu)區(qū)域，大小約0.2-1微米。這種結(jié)構(gòu)首先在Hela細(xì)胞中被發(fā)現(xiàn)，大約在每個細(xì)胞核中存在10-30個。后續(xù)研究表明，這種結(jié)構(gòu)存在于所有的人類原代細(xì)胞，轉(zhuǎn)化細(xì)胞以及組織切片中。）

摘要：The inflammasome has an essential function in innate immune, responding to a wide variety of stimuli. Here we show that the lncRNA Neat1 promotes the activation of several inflammasomes. Neat1 associates with the NLRP3, NLRC4, and AIM2 inflammasomes in mouse macrophages to enhance their assembly and subsequent pro-caspase-1 processing. Neat1 also stabilizes the mature caspase-1 to promote interleukin-1β production and pyroptosis. Upon stimulation with inflammasome-activating signals, Neat1, which normally resides in the paraspeckles, disassociates from these nuclear bodies and translocates to the cytoplasm to modulate inflammasome activation using above mechanism. Neat1 is also up-regulated under hypoxic conditions in a HIF-2α-dependent manner, mediating the effect of hypoxia on inflammasomes. Moreover, in the mouse models of peritonitis and pneumonia, Neat1 deficiency significantly reduces inflammatory responses. 

3.LncRNAs-directed PTEN enzymatic switch governs epithelial-mesenchymal transition.

Cell Res15.3931區(qū)1. 2019 Apr

分子機(jī)制：已知PTEN是抑癌基因，其具有雙特異性-磷酸酯酶的活性，但是從未有報道對其雙特異性磷酸酯酶的功能有報道。K27介導(dǎo)的PTEN的66和68賴氨酸位點的多泛素化修飾，可使其從磷酸肌醇/絡(luò)氨酸磷酸酯酶活性切換成為絲氨酸/絡(luò)氨酸磷酸酯酶活性。高糖, TGF-β, CTGF, SHH, 以及 IL-6誘導(dǎo)一個叫做lncRNA MEX3C的上調(diào)表達(dá)，其可直接介導(dǎo)K27介導(dǎo)的PTEN的66和68賴氨酸位點的多泛素化修飾，促進(jìn)了PTEN發(fā)揮ser/tyr磷酸酯酶活性。而使得TWIST1, SNAI1以及YAP1的ser氨酸殘基以及tyr氨酸殘基去磷酸化，從而使得這些EMT相關(guān)marker積累，誘導(dǎo)EMT的潛在發(fā)生。

（PTEN基因，編碼由403個氨基酸組成的蛋白質(zhì)，具有磷酸酯酶的活性。PTEN蛋白可通過拮抗酪氨酸激酶等磷酸化酶的活性而抑制腫瘤的發(fā)生發(fā)展。實驗表明，將野生型PTEN基因轉(zhuǎn)染到該基因異常的膠質(zhì)母細(xì)胞瘤后，腫瘤細(xì)胞的生長、侵襲能力受到明顯抑制，發(fā)現(xiàn)其對腫瘤細(xì)胞的酪氨酸激酶FAK（focal adhesion kinase ）的活性有明顯的抑制作用。此外，PTEN蛋白還可通過特異性地使IP3的第三位磷酸去磷酸化而間接地抑制胰島素誘導(dǎo)的磷酸肌醇-3激酶的活性，而IP3是胰島素調(diào)節(jié)細(xì)胞生長信號通路中的重要的第二信使，可見PTEN蛋白在細(xì)胞生長信號通路中起重要作用。）

摘要：Despite the structural conservation of PTEN with dual-specificity phosphatases, there have been no reports regarding the regulatory mechanisms that underlie this potential dual-phosphatase activity. Here, we report that K27-linked polyubiquitination of PTEN at lysines 66 and 80 switches its phosphoinositide/protein tyrosine phosphatase activity to protein serine/threonine phosphatase activity. Mechanistically, high glucose, TGF-β, CTGF, SHH, and IL-6 induce the expression of a long non-coding RNA, GAEA (Glucose Aroused for EMT Activation), which associates with an RNA-binding E3 ligase, MEX3C, and enhances its enzymatic activity, leading to the K27-linked polyubiquitination of PTEN. The MEX3C-catalyzed PTENK27-polyUb activates its protein serine/threonine phosphatase activity and inhibits its phosphatidylinositol/protein tyrosine phosphatase activity. With this altered enzymatic activity, PTENK27-polyUb dephosphorylates the phosphoserine/threonine residues of TWIST1, SNAI1, and YAP1, leading to accumulation of these master regulators of EMT. Animals with genetic inhibition of PTENK27-polyUb, by a single nucleotide mutation generated using CRISPR/Cas9 (PtenK80R/K80R), exhibit inhibition of EMT markers during mammary gland morphogenesis in pregnancy/lactation and during cutaneous wound healing processes. Our findings illustrate an unexpected paradigm in which the lncRNA-dependent switch in PTEN protein serine/threonine phosphatase activity is important for physiological homeostasis and disease development.

4.A Transforming Growth Factor-β and H19 Signaling Axis in Tumor-Initiating Hepatocytes That Regulates Hepatic Carcinogenesis.

Hepatology14.0791區(qū)1. 2019 Apr

分子機(jī)制：肝癌進(jìn)展中TGF-β信號通路發(fā)揮著不同階段的功能。作者把TGF-βR2失活后，體內(nèi)外實驗發(fā)現(xiàn)肝癌細(xì)胞TIC（tumor-initiating?cell）細(xì)胞增殖情況更加瘋狂，且小鼠體內(nèi)有更多的轉(zhuǎn)移灶。機(jī)制上，TGF-βR2失活后，一個lncRNA H19上調(diào)表達(dá)了至少5倍，而TGF-β處理后H19的表達(dá)下降了，進(jìn)一步的機(jī)制表明SOX2轉(zhuǎn)錄因子調(diào)控者H19的表達(dá)，調(diào)控著TGF-β-H19的調(diào)控信號。

（腫瘤干細(xì)胞（cancer?stem?cell,?CSC）也稱為腫瘤起源細(xì)胞（tumor-initiating?cell），是從腫瘤組織中分離或鑒定的少數(shù)細(xì)胞，具有無限的自我更新和誘導(dǎo)腫瘤發(fā)生的能力，是腫瘤產(chǎn)生的種子細(xì)胞。）

摘要：Functions of transforming growth factor-β (TGF-β) in the liver vary depending on specific cell types and their temporal response to TGF-β during different stages of hepatocarcinogenesis (HCG). Through analysis of tumor tissues from hepatocellular carcinoma (HCC) patients, we were able to cluster hepatic epithelial cell-derived TGF-β gene signatures in association with distinct clinical prognoses.  RNA sequencing (RNA-seq) analysis identified H19 as one of the most up-regulated long noncoding RNA (lncRNA) in association with Tgfbr2 inactivation in TICs. Tgfbr2 inactivation by Ad-Cre led to a 5-fold increase of H19 expression in TICs. Accordingly, TGF-β treatment reduced H19 expression. We observed that forced overexpression of Sox2 in TICs increased transcription of H19, whereas knockdown of Sox2 decreased it. Furthermore, depletion of H19 reduced the progenitor property of TICs in vitro and decreased their tumorigenic potential in vivo. Finally, we observed a low level of H19 mRNA expression in human HCC tissues from patients with the epithelial TGF-β gene signature in association with favorable prognosis. Conclusion: Our findings describe a TGF-β and H19 signaling axis by Sox2 in TICs that importantly regulates HCG.

5.LncIRS1 controls muscle atrophy via sponging miR-15 family to activate IGF1-PI3K/AKT pathway.

J Cachexia Sarcopenia Muscle12.5111區(qū). 2019 Ap

分子機(jī)制：作者研究的是肌肉萎縮課題，其首先用生信的方式構(gòu)建了ceRNA網(wǎng)絡(luò)。通過實驗驗證了lncIRS1可同時吸附家族miRNA如miR-15a, miR-15b-5p以及 miR-15c-5p，從而促進(jìn) IRS1基因的表達(dá)。而IRS1基因是IGF1 receptor的下游靶基因，同時lncIRS1還可以促進(jìn)AKT蛋白的磷酸化，激活PI3K-AKT信號通路。

摘要：We constructed a myogenesis-associated lncRNA-miRNA-gene network and identified a novel ceRNA lncRNA named lncIRS1 that is specifically enriched in skeletal muscle. LncIRS1 could regulate myoblast proliferation and differentiation in vitro, and muscle mass and mean muscle fibre in vivo. LncIRS1 increases gradually during myogenic differentiation. Mechanistically, lncIRS1 acts as a ceRNA for miR-15a, miR-15b-5p, and miR-15c-5p to regulate IRS1 expression, which is the downstream of the IGF1 receptor. Overexpression of lncIRS1 not only increased the protein abundance of IRS1 but also promoted phosphorylation level of AKT (p-AKT) a central component of insulin-like growth factor-1 pathway. Furthermore, lncIRS1 regulates the expression of atrophy-related genes and can rescue muscle atrophy.