• 【腹侧前额叶皮层的局部电场电势和峰值活动中信号新颖性的差异表示模型。】 复制标题 收藏 收藏
    DOI:10.1162/NECO_a_00388 复制DOI
    作者列表:Lee JH,Tsunada J,Cohen YE
    BACKGROUND & AIMS: :Local field potentials (LFPs) and spiking activity reflect different types of information procssing. For example, neurophysiological studies indicate that signal novelty in the ventrolateral prefrontal cortex is differentially represented by LFPs and spiking activity: LFPs habituate to repeated stimulus presentations, whereas spiking activity does not. The neural mechanisms that allow for this differential representation between LFPs and spiking activity are not clear. Here, we model and simulate LFPs and spiking activity of neurons in the ventrolateral prefrontal cortex in order to elucidate potential mechanisms underlying this differential representation. We demonstrate that dynamic negative-feedback loops cause LFPs to habituate in response to repeated presentations of the same stimulus while spiking activity is maintained. This disassociation between LFPs and spiking activity may be a mechanism by which LFPs code stimulus novelty, whereas spiking activity carries abstract information, such as category membership and decision-related activity.
    背景与目标: :局部场电势(LFP)和尖峰活动反映了不同类型的信息处理。例如,神经生理学研究表明,腹侧前额叶皮层的信号新颖性由LFP和加标活动差异表示:LFP习惯于重复刺激,而加标活动则没有。 LFP和加标活性之间存在差异的神经机制尚不清楚。在这里,我们建模和模拟腹侧前额叶皮层的LFP和神经元的突波活动,以阐明这种差异表示的潜在机制。我们证明动态负反馈循环导致LFP习惯于响应相同刺激的重复呈现,同时维持尖峰活动。 LFP和加标活动之间的这种分离可能是LFP编码刺激新颖性的机制,而加标活动携带抽象信息,例如类别成员资格和与决策相关的活动。
  • 【在Raf / MEK /细胞外信号调节激酶的肿瘤抑制信号传导中,由mortalin / HSPA9介导的开关。】 复制标题 收藏 收藏
    DOI:10.1128/MCB.00021-13 复制DOI
    作者列表:Wu PK,Hong SK,Veeranki S,Karkhanis M,Starenki D,Plaza JA,Park JI
    BACKGROUND & AIMS: :Dysregulated Raf/MEK/extracellular signal-regulated kinase (ERK) signaling, a common hallmark of tumorigenesis, can trigger innate tumor-suppressive mechanisms, which must be inactivated for carcinogenesis to occur. This innate tumor-suppressive signaling may provide a potential therapeutic target. Here we report that mortalin (HSPA9/GRP75/PBP74) is a novel negative regulator of Raf/MEK/ERK and may provide a target for the reactivation of tumor-suppressive signaling of the pathway in cancer. We found that mortalin is present in the MEK1/MEK2 proteome and is upregulated in human melanoma biopsy specimens. In different MEK/ERK-activated cancer cell lines, mortalin depletion induced cell death and growth arrest, which was accompanied by increased p21(CIP1) transcription and MEK/ERK activity. Remarkably, MEK/ERK activity was necessary for mortalin depletion to induce p21(CIP1) expression in B-Raf(V600E)-transformed cancer cells regardless of their p53 status. In contrast, in cell types exhibiting normal MEK/ERK status, mortalin overexpression suppressed B-Raf(V600E)- or ΔRaf-1:ER-induced MEK/ERK activation, p21(CIP1) expression, and cell cycle arrest. Other HSP70 family chaperones could not effectively replace mortalin for p21(CIP1) regulation, suggesting a unique role for mortalin. These findings reveal a novel mechanism underlying p21(CIP1) regulation in MEK/ERK-activated cancer and identify mortalin as a molecular switch that mediates the tumor-suppressive versus oncogenic result of dysregulated Raf/MEK/ERK signaling. Our study also demonstrates that p21(CIP1) has dual effects under mortalin-depleted conditions, i.e., mediating cell cycle arrest while limiting cell death.
    背景与目标: :Raf / MEK /细胞外信号调节激酶(ERK)信号失调,是肿瘤发生的常见标志,可以触发固有的肿瘤抑制机制,必须将其抑制才能发生癌变。这种先天性的肿瘤抑制信号传导可能会提供潜在的治疗靶点。在这里我们报告,mortalin(HSPA9 / GRP75 / PBP74)是Raf / MEK / ERK的新型负调节剂,可能为癌症通路中抑癌信号的重新激活提供目标。我们发现,mortalin存在于MEK1 / MEK2蛋白质组中,并在人类黑素瘤活检标本中上调。在不同的MEK / ERK激活的癌细胞系中,凡尔林耗竭诱导细胞死亡和生长停滞,并伴随着p21(CIP1)转录和MEK / ERK活性的增加。值得注意的是,MEK / ERK活性对于在B-Raf(V600E)转化的癌细胞中诱导p21(CIP1)表达的人乳清蛋白耗尽是必需的,而与p53的状态无关。相反,在表现出正常MEK / ERK状态的细胞类型中,mortalin过表达抑制了B-Raf(V600E)-或ΔRaf-1:ER诱导的MEK / ERK活化,p21(CIP1)表达和细胞周期停滞。其他HSP70家族分子伴侣不能有效替代p21(CIP1)调节中的mortalin,这提示了mortalin的独特作用。这些发现揭示了MEK / ERK激活的癌症中p21(CIP1)调节的基础的新机制,并确定了mortalin作为介导Raf / MEK / ERK信号失调的肿瘤抑制和致癌结果的分子开关。我们的研究还表明,p21(CIP1)在耗尽凡尔林的条件下具有双重作用,即在限制细胞死亡的同时介导细胞周期停滞。
  • 【天然化合物通过调节人结肠癌细胞中信号转导和miRNA表达的抗癌作用。】 复制标题 收藏 收藏
    DOI:10.1016/j.jnutbio.2013.04.006 复制DOI
    作者列表:Kumazaki M,Noguchi S,Yasui Y,Iwasaki J,Shinohara H,Yamada N,Akao Y
    BACKGROUND & AIMS: :Much evidence indicates that various naturally occurring compounds have an anti-cancer effect, but the detailed mechanisms are not well understood. In this study, we selected anti-cancer phytochemicals such as epigallocatechin-3-gallate (EGCG), resveratrol (RES) and α-mangostin (α-M), all of which are well-characterized chemopreventive agents. We sought to elucidate the mechanism of their anti-cancer effects and the synergistic effects obtained by combined treatment with the anti-cancer drug 5-fluorouracil (5-FU) in three human colon cancer cell lines. The numbers of viable cells were consistently decreased by the treatment with EGCG, RES or α-M at more than 10 μM in all three cell lines tested. All compounds mainly induced apoptosis and suppressed the PI3K/Akt signaling pathway. Additionally, α-M, which had the greatest PI3K/Akt-suppressing activity, also suppressed MAP kinase (MAPK)/Erk1/2 signaling. Importantly, the combination treatment with RES and 5-FU induced a remarkably synergistic enhancement of growth inhibition and apoptosis through the additional suppression of the MAPK/Erk1/2 signaling pathway in colon cancer DLD-1 cells. Interestingly, RES increased the intracellular expression level of miR-34a, which down-regulated the target gene E2F3 and its downstream Sirt1, resulting in growth inhibition. These findings indicate that these compounds functioned as chemosensitizers when combined with anti-cancer drugs through the modulation of apoptotic and growth-related signaling pathways. Also, RES exerted its anti-cancer activity in part through a newly defined mechanism, i.e., the miR-34a/E2F3/Sirt1 cascade.
    背景与目标: :许多证据表明,各种天然存在的化合物均具有抗癌作用,但其详细机理尚不清楚。在这项研究中,我们选择了抗癌植物化学物质,例如表没食子儿茶素-3-没食子酸酯(EGCG),白藜芦醇(RES)和α-芒果(α-M),它们都是特征明确的化学预防剂。我们试图阐明它们的抗癌作用机理以及通过与抗癌药5-氟尿嘧啶(5-FU)联合治疗在三种人结肠癌细胞系中获得的协同作用。在所有测试的所有三个细胞系中,通过以大于10μM的EGCG,RES或α-M处理,存活细胞的数量持续减少。所有化合物主要诱导细胞凋亡并抑制PI3K / Akt信号传导途径。此外,具有最大的PI3K / Akt抑制活性的α-M也抑制了MAP激酶(MAPK)/ Erk1 / 2信号传导。重要的是,通过RES和5-FU的联合治疗,通过额外抑制结肠癌DLD-1细胞中的MAPK / Erk1 / 2信号传导途径,可显着协同增强生长抑制和凋亡。有趣的是,RES增加了miR-34a的细胞内表达水平,从而下调了靶基因E2F3及其下游Sirt1,从而抑制了生长。这些发现表明,当这些化合物与抗癌药物通过调节细胞凋亡和与生长相关的信号通路结合在一起时,它们起化学增敏剂的作用。此外,RES部分通过新定义的机制即miR-34a / E2F3 / Sirt1级联发挥其抗癌活性。
  • 【猴纹状皮质中的神经元同步:眼内信号流和对尖峰频率的依赖性。】 复制标题 收藏 收藏
    DOI:10.1007/BF00248509 复制DOI
    作者列表:Aiple F,Krüger J
    BACKGROUND & AIMS: :A hypercolumn of monkey striate cortex was studied with an array of 30 closely spaced microelectrodes. Prominent broad peaks appearing in spike train correlograms are considered here. These were not due to shared stimulation, were mostly 30 to 100 ms wide, and were presumably the consequence of intraretinal lateral interactions. The correlogram peak areas were found to be predictable from the products of the spike rates, to which they were proportional. One can conclude that the correlation occurs before the overall reduction of spike rates from retina to cortex takes place. Furthermore, when a neurone dominated by one eye was stimulated via that eye, the correlogram formed with a neurone dominated by the other eye showed a displaced peak, indicating that excitation traveled from the well-responding to the unresponsive neurone in about 10 ms. When a left-eye stimulus was delivered, the same pair of neurones had a correlogram with a reversed peak displacement. This effect was only observed in layers IVb and c, indicating that in these layers the paths from the two eyes to a given cell are of unequal length, whereas in other layers, cells receive input from both eyes via similar connections differing only in strength.
    背景与目标: :研究了猴纹状皮质的一个超柱,该阵列由30个紧密排列的微电极组成。这里考虑了在尖峰列相关图中出现的突出的宽峰。这些不是由于共同的刺激,主要是30到100毫秒宽,大概是视网膜内侧向相互作用的结果。发现关联图的峰面积可以从峰值速率的乘积中预测出来,它们与峰值速率成正比。可以得出这样的结论:相关性发生在从视网膜到皮层的刺突率总体降低之前。此外,当通过一只眼睛支配一只眼睛的神经元受到刺激时,与另一只眼睛支配的神经元形成的相关图显示了一个位移峰,表明激发在大约10毫秒内从响应良好的神经元传播到了无反应的神经元。传递左眼刺激时,同一对神经元的相关图具有相反的峰值位移。仅在第IVb和c层中观察到了这种影响,表明在这些层中,从两只眼睛到给定单元格的路径长度不等,而在其他层中,单元格则通过强度仅不同的相似连接来接收来自两只眼睛的输入。
  • 【水稻和人类SRP19多肽与信号识别颗粒RNA的相互作用。】 复制标题 收藏 收藏
    DOI:10.1023/a:1005834026743 复制DOI
    作者列表:Chittenden K,Gowda K,Black SD,Zwieb C
    BACKGROUND & AIMS: The signal recognition particle (SRP) controls the transport of secretory proteins into and across lipid bilayers. SRP-like ribonucleoprotein complexes exist in all organisms, including plants. We characterized the rice SRP RNA and its primary RNA binding protein, SRP19. The secondary structure of the rice SRP RNA was similar to that found in other eukaryotes; however, as in other plant SRP RNAs, a GUUUCA hexamer sequence replaced the highly conserved GNRA-tetranucleotide loop motif at the apex of helix 8. The small domain of the rice SRP RNA was reduced considerably. Structurally, rice SRP19 lacked two small region that can be present in other SRP19 homologues. Conservative structure prediction and site-directed mutagenesis of rice and human SRP19 polypeptides indicated that binding to the SRP RNAs occurred via a loop that is present in the N-domain of both proteins. Rice SRP19 protein was able to form a stable complex with the rice SRP RNA in vitro. Furthermore, heterologous ribonucleoprotein complexes with components of the human SRP were assembled, thus confirming a high degree of structural and functional conservation between plant and mammalian SRP components.

    背景与目标: 信号识别颗粒(SRP)控制分泌性蛋白质进入和穿过脂质双层的转运。 SRP样核糖核蛋白复合物存在于所有生物体中,包括植物。我们表征了水稻SRP RNA及其主要RNA结合蛋白SRP19。水稻SRP RNA的二级结构与其他真核生物相似。但是,与其他植物SRP RNA一样,GUUUCA六聚体序列取代了螺旋8顶点的高度保守的GNRA-四核苷酸环基序。水稻SRP RNA的小结构域大大减少了。在结构上,水稻SRP19缺少两个可以在其他SRP19同源物中存在的小区域。水稻和人SRP19多肽的保守结构预测和定点诱变表明与SRP RNA的结合是通过两个蛋白质N结构域中存在的环发生的。水稻SRP19蛋白能够在体外与水稻SRP RNA形成稳定的复合物。此外,组装了具有人类SRP成分的异源核糖核蛋白复合物,从而确认了植物和哺乳动物SRP成分之间的高度结构和功能保守性。

  • 【细胞外连接依赖性CD45RB酶活性负调节脂质筏信号转导。】 复制标题 收藏 收藏
    DOI:10.1182/blood-2008-04-150987 复制DOI
    作者列表:Parikh K,Poppema S,Peppelenbosch MP,Visser L
    BACKGROUND & AIMS: :CD45 is the most prominent membrane protein on lymphocytes. The function and regulation of this protein tyrosine phosphatase remain largely obscure, mainly because of the lack of a known ligand, and it still remains unknown whether such tyrosine phosphatases are subject to extracellular control at all. We report that an anti-CD45RB antibody (Ab) that prevents rejection and induces tolerance activates CD45RB tyrosine phosphatase enzymatic activity in T lymphocytes, allowing us to directly monitor the effects of increased CD45RB activity on signal transduction. Using both kinase substrate peptide arrays as well as conventional biochemistry, we also provide evidence of the various kinases involved in bringing about the inhibitory effect of this Ab on CD3-induced T-cell receptor signaling. Furthermore, we report that activated CD45RB translocates to lipid rafts and interferes with lipid raft localization and activation state of CD45 substrate Lck. Thus, these findings indeed prove that CD45 is subject to extracellular control and also define a novel mechanism by which receptor tyrosine phosphatases control lymphocyte biology and provide further insight into the intracellular signaling pathways effected by anti-CD45RB monoclonal Ab treatment.
    背景与目标: :CD45是淋巴细胞上最突出的膜蛋白。该蛋白酪氨酸磷酸酶的功能和调节仍然很大程度上不清楚,这主要是由于缺乏已知的配体,并且仍然不清楚这种酪氨酸磷酸酶是否完全受到细胞外控制。我们报告说,一种抗CD45RB抗体(Ab)可以防止排斥并诱导耐受,从而激活T淋巴细胞中的CD45RB酪氨酸磷酸酶的酶促活性,从而使我们能够直接监测信号传导中CD45RB活性增加的影响。使用激酶底物肽阵列以及常规的生物化学,我们还提供了与导致这种Ab对CD3诱导的T细胞受体信号转导的抑制作用有关的各种激酶的证据。此外,我们报告激活的CD45RB易位到脂质筏,并干扰脂质筏的本地化和CD45底物Lck的激活状态。因此,这些发现确实证明了CD45受到细胞外控制,并且还定义了一种新的机制,受体酪氨酸磷酸酶通过该机制控制淋巴细胞生物学,并进一步揭示了抗CD45RB单克隆抗体治疗影响的细胞内信号传导途径。
  • 【肝移植受者的化脓性肝脓肿:复发和再移植风险的警告信号。】 复制标题 收藏 收藏
    DOI:10.1111/tid.13360 复制DOI
    作者列表:Lafont E,Roux O,de Lastours V,Dokmak S,Leflon V,Fantin B,Lefort A
    BACKGROUND & AIMS: BACKGROUND:Pyogenic liver abscesses in liver transplant recipients (PLA-LTR) are a rare disease whose specificities compared with PLA in non-transplanted patients (PLA-C) are unknown. METHODS:A retrospective case-control study was conducted in a French academic hospital from January 1, 2010, to December 31, 2014. RESULTS:Among 176 patients diagnosed with PLA, 14 were LTR; each case was matched with 3 PLA-C controls by date of PLA diagnosis and pathophysiological mechanism of PLA. Median time from liver transplantation to PLA diagnosis was 34.5 months. Among 14 PLA-LTR, 8/14 (57.1%) had bacteremia and 10/14 (71.4%) had positive PLA cultures. Most commonly isolated bacteria were Enterobacteriaceae (9/14; 64.3%), Enterococcus spp. (4/14; 28.6%), and anaerobic bacteria (3/14; 21.4%). Clinical, radiological, and microbiological characteristics did not significantly differ between PLA-LTR and PLA-C but there was a tendency toward more diabetic patients and a less acute presentation. All but one PLA-LTR were associated with ischemic cholangitis, whereas this was a rare cause among PLA-C (13/14 vs 3/42, respectively, P < .001) among patients with PLA-LTR. In contrast, hepatobiliary neoplasia was rare in PLA-LTR but frequent in PLA-C (1/14 vs 24/42, P = .001). No significant difference was found between PLA-LTR and PLA-C in terms of duration of antibiotic therapy (6.5 and 6 weeks, respectively), PLA drainage rates (10/14 and 26/42, respectively), or mortality at 12 months after PLA diagnosis (2/14 and 5/42, respectively). Recurrence rates within the first year were observed in 6/14 patients (42.9%), and retransplantation was needed in 5/14 (35.7%). CONCLUSIONS:Occurrence of PLA in LTR is a severe event leading to high risk of recurrence and retransplantation.
    背景与目标: 背景:肝移植受者的化脓性肝脓肿(PLA-LTR)是一种罕见疾病,与非移植患者(PLA-C)相比,PLA的特异性尚不清楚。
    方法:回顾性病例对照研究于2010年1月1日至2014年12月31日在法国一家学术医院进行。
    结果:在诊断为PLA的176例患者中,有14例为LTR。截至PLA诊断日期和PLA的病理生理机制,每例均与3例PLA-C对照相匹配。从肝移植到PLA诊断的中位时间为34.5个月。在14个PLA-LTR中,有8/14(57.1%)的菌血症和10/14(71.4%)的PLA培养呈阳性。最常见的细菌是肠杆菌科(9/14; 64.3%),肠球菌。 (4/14; 28.6%)和厌氧菌(3/14; 21.4%)。 PLA-LTR和PLA-C之间的临床,放射学和微生物学特征无显着差异,但存在糖尿病患者增多,急性症状减少的趋势。除了一个PLA-LTR以外,所有患者均与缺血性胆管炎有关,而这是PLA-LTR患者中PLA-C罕见的原因(分别为13/14 vs 3/42,P <.001)。相比之下,PLA-LTR中肝胆肿瘤很少见,而PLA-C中则很常见(1/14 vs 24/42,P = .001)。在抗生素治疗的持续时间(分别为6.5和6周),PLA引流率(分别为10/14和26/42)或术后12个月的死亡率方面,PLA-LTR和PLA-C之间没有发现显着差异。 PLA诊断(分别为2/14和5/42)。在第一年内,有6/14例患者(42.9%)出现复发率,而在5/14例中需要再移植(35.7%)。
    结论:LTR中PLA的发生是严重事件,导致复发和再移植的高风险。
  • 【应力依赖性机械感受器将肠道生物力学与感觉信号转导联系起来的证据。】 复制标题 收藏 收藏
    DOI:10.1113/expphysiol.2012.066019 复制DOI
    作者列表:Gregersen H,Jiang W,Liao D,Grundy D
    BACKGROUND & AIMS: :Sensory nerve endings are widely distributed throughout the body. Neither the nature of the mechanosensitive channels nor the principal mechanical stimulus for these receptors is known. Afferents supplying the gastrointestinal tract responding to distension and contraction are responsible for co-ordinated reflex control, feeding behaviour and sensations, including pain. Different populations of intestinal afferent fibres follow different pathways to the CNS, have different terminal fields and possess different thresholds for activation that may reflect the extent to which mechanical forces are distributed and dissipated by non-neural structures in the bowel wall. In this study, we have characterized the stimulus-response function of afferent fibres innervating the rat jejunum, correlating luminal distensions in the bowel wall with the firing frequency of mesenteric afferent nerve bundles. Combining video imaging with intraluminal pressure recordings and utilizing a strain softening protocol, we have determined whether mechanoreceptors respond primarily to stress or strain. Multiunit afferent recordings were separated using spike discrimination software into low-threshold (LT) and high-threshold (HT) single units. For multifibre afferent recordings and both LT and HT single units, we observed a linear relationship between circumferential stress and mesenteric afferent discharge that was independent of distension-induced tissue softening, with correlation coefficients >0.9. A fivefold change in the rate of applied distension did not significantly alter the magnitude of the afferent response and the linearity of the stress-dependent mechanotransduction in both multifibre preparations and the LT and HT afferent fibres (P > 0.2). Thus, the firing characteristics of intestinal mechanoreceptors are linearly associated with the input in terms of mechanical stress.
    背景与目标: :感觉神经末梢广泛分布于全身。机械敏感通道的性质或这些受体的主要机械刺激均未知。提供胃肠道响应扩张和收缩的传入者负责协调反射控制,进食行为和感觉,包括疼痛。不同的肠道传入纤维种群遵循不同的通向中枢神经系统的途径,具有不同的终末场,并具有不同的激活阈值,这可能反映了肠壁中非神经结构对机械力的分布和消散程度。在这项研究中,我们表征了支配大鼠空肠的传入纤维的刺激响应功能,将肠壁的腔内扩张与肠系膜传入神经束的发射频率相关联。结合视频成像与腔内压力记录并利用应变软化协议,我们已经确定了机械感受器是否主要对应力或应变作出反应。使用尖峰识别软件将多单元传入记录分离为低阈值(LT)和高阈值(HT)单个单元。对于多纤维传入记录以及LT和HT单个单元,我们观察到周向应力与肠系膜传入传入放电之间的线性关系,与膨胀诱导的组织软化无关,相关系数> 0.9。在多纤维制剂以及LT和HT传入纤维中,施加的扩张速率的五倍变化不会显着改变传入反应的大小和应力依赖性机械传导的线性(P> 0.2)。因此,就机械应力而言,肠机械感受器的发射特性与输入线性相关。
  • 【LncRNA FOXC2-AS1通过激活Ca2-FAK信号通路来增强FOXC2 mRNA的稳定性,从而促进结直肠癌的进展。】 复制标题 收藏 收藏
    DOI:10.1038/s41419-020-2633-7 复制DOI
    作者列表:Pan K,Xie Y
    BACKGROUND & AIMS: :Long noncoding RNAs (lncRNAs) have been confirmed, which are involved in tumorigenesis and metastasis in colorectal cancer (CRC). FOXC2 antisense RNA 1 (FOXC2-AS1) was reported, facilitating the proliferation and progression in several cancers. However, the role of FOXC2-AS1 in CRC cell migration and metastasis is not unclear. In this study, we observed that lncRNA FOXC2-AS1 was upregulated in CRC tissues, and its high expression indicated the poor survival in CRC patients. Meanwhile, FOXC2-AS1 was higher in CRC tissues with metastasis than that of nonmetastatic tumor tissues. We found that FOXC2-AS1 was predominately expressed in the nucleus of tissues and cells. FOXC2-AS1 knockdown suppressed CRC cell growth, invasion, and metastasis in vitro and in vivo. Moreover, FOXC2-AS1 could positively regulate the neighboring gene FOXC2 and stabilized FOXC2 mRNA by forming a RNA duplex. Meanwhile, ectopic expression of FOXC2 could obviously alleviate the suppressed effects caused by silencing FOXC2-AS1. For the mechanism, FOXC2-AS1 knockdown could reduce intracellular Ca2+ levels, inhibited FA formation and FAK signaling, and these suppressed effects were mitigated by increasing FOXC2 expression. These results demonstrated that FOXC2-AS1 enhances FOXC2 mRNA stability to promote CRC proliferation, migration, and invasion by activation of Ca2+-FAK signaling, which implicates that FOXC2-AS1 may represent a latent effective therapeutic target for CRC progression.
    背景与目标: :已证实长非编码RNA(lncRNA),它们参与了结直肠癌(CRC)的肿瘤发生和转移。据报道,FOXC2反义RNA 1(FOXC2-AS1)促进了几种癌症的增殖和进展。然而,FOXC2-AS1在CRC细胞迁移和转移中的作用尚不清楚。在这项研究中,我们观察到lncRNA FOXC2-AS1在CRC组织中被上调,其高表达表明CRC患者的生存期较差。同时,转移的CRC组织中的FOXC2-AS1高于非转移性肿瘤组织中的FOXC2-AS1。我们发现FOXC2-AS1主要在组织和细胞的细胞核中表达。 FOXC2-AS1组合物在体外和体内均抑制CRC细胞的生长,侵袭和转移。此外,FOXC2-AS1可以通过形成RNA双链体来正向调节邻近基因FOXC2,并稳定FOXC2 mRNA。同时,异位表达FOXC2可明显减轻沉默FOXC2-AS1引起的抑制作用。对于该机制,FOXC2-AS1敲低可以降低细胞内Ca2水平,抑制FA形成和FAK信号传导,并且通过增加FOXC2表达来减轻这些抑制作用。这些结果表明FOXC2-AS1通过激活Ca2-FAK信号来增强FOXC2 mRNA的稳定性,从而促进CRC增殖,迁移和侵袭,这暗示FOXC2-AS1可能代表了CRC进展的潜在有效治疗靶点。
  • 【具有细胞转导和保留肽融合的金属硫蛋白双模式增强。】 复制标题 收藏 收藏
    DOI:10.1016/j.jconrel.2013.07.009 复制DOI
    作者列表:Lim KS,Lim MH,Won YW,Kim JK,Kang YC,Park EJ,Chae JW,Kim SM,Ryu SE,Pak YK,Kim YH
    BACKGROUND & AIMS: :Protein transduction domains (PTDs), also known as cell-penetrating peptides (CPPs), have been developed as effective systems for delivering bio-active cargos such as proteins, genes and particles. Further improvements on cell-specific targeting, intracellular organelle targeting and intracellular retention are still necessary to enhance the therapeutic effect of PTD fusion proteins. In order to enhance the cell transduction and retention of anti-oxidative metallothionein protein (MT), MT was recombinantly fused with transcriptional activator (Tat) with or without a short peptide (sMTS) derived from mitochondria malate dehydrogenase (mMDH). Cellular uptake and retention time of fusion protein were significantly increased in the H9c2 cell by sMTS. The Tat-sMTS-MT (TMM) fusion protein protected H9c2 cells more effectively against hypoxia, hyperglycemia and combination compared with Tat-MT (TM) by reducing intracellular ROS level. It maintained the normal blood glucose level over an extended period of time in a streptozotocin-induced diabetic mouse model. PTD-sMTS-MT fusion protein has a potential to be used as a therapeutic protein for the treatment or prevention of diabetes and diabetic complications.
    背景与目标: :蛋白转导域(PTDs),也称为细胞穿透肽(CPPs),已被开发为有效的系统,可输送蛋白质,基因和颗粒等具有生物活性的货物。为了增强PTD融合蛋白的治疗效果,仍需要对细胞特异性靶向,细胞内细胞器靶向和细胞内保留进行进一步的改进。为了增强细胞转导和抗氧化金属硫蛋白蛋白(MT)的保留,将MT与转录激活剂(Tat)重组融合,融合或不融合衍生自线粒体苹果酸脱氢酶(mMDH)的短肽(sMTS)。 sMTS在H9c2细胞中显着增加了融合蛋白的细胞摄取和保留时间。与Tat-MT(TM)相比,Tat-sMTS-MT(TMM)融合蛋白通过降低细胞内ROS水平,更有效地保护了H9c2细胞免受缺氧,高血糖症和联合症的侵害。在链脲佐菌素诱导的糖尿病小鼠模型中,它可以长时间维持正常的血糖水平。 PTD-sMTS-MT融合蛋白具有用作治疗或预防糖尿病和糖尿病并发症的治疗蛋白的潜力。
  • 11 A closer look at energy transduction in muscle. 复制标题 收藏 收藏

    【仔细研究肌肉中的能量转导。】 复制标题 收藏 收藏
    DOI:10.1073/pnas.0705525104 复制DOI
    作者列表:Onishi H,Morales MF
    BACKGROUND & AIMS: :Muscular force is the sum of unitary force interactions generated as filaments of myosins move forcibly along parallel filaments of actins, understanding that the free energy required comes from myosin-catalyzed ATP hydrolysis. Using results from conventional biochemistry, our own mutational studies, and diffraction images from others, we attempt, in molecular detail, an account of a unitary interaction, i.e., what happens after a traveling myosin head, bearing an ADP-P(i), reaches the next station of an actin filament in its path. We first construct a reasonable model of the myosin head and actin regions that meet to form the "weakly bound state". Separately, we consider Holmes' model of the rigor state [Holmes, K. C., Angert, I., Kull, F. J., Jahn, W. & Schröder, R. R. (2003) Nature 425, 423-427], supplemented with several heretofore missing residues, thus realizing the "strongly bound state." Comparing states suggests how influences initiated at the interface travel elsewhere in myosin to discharge various functions, including striking the actins. Overall, state change seems to occur by attachment of a hydrophobic triplet (Trp-546, Phe-547, and Pro-548) of myosin to an actin conduit with a hydrophobic guiding rail (Ile-341, Ile-345, Leu-349, and Phe-352) and the subsequent linear movement of the triplet along the rail.
    背景与目标: :肌力是肌球蛋白丝沿着平行的肌动蛋白丝强行运动时产生的单位力相互作用的总和,要了解所需的自由能来自肌球蛋白催化的ATP水解。利用常规生物化学的结果,我们自己的突变研究以及其他研究的衍射图像,我们尝试在分子细节上解释整体相互作用,即,在移动的肌球蛋白头部携带ADP-P(i)后发生的情况,到达其路径中肌动蛋白丝的下一个位置。我们首先构建一个肌球蛋白头部和肌动蛋白区域的合理模型,这些区域相遇形成“弱结合状态”。单独地,我们考虑严格状态的福尔摩斯模型[Holmes,KC,Angert,I.,Kull,FJ,Jahn,W.&Schröder,RR(2003)Nature 425,423-427],并补充了一些迄今为止遗漏的残基,从而实现“强绑定状态”。比较状态表明在界面处引发的影响如何在肌球蛋白中传播到其他位置,以发挥各种功能,包括打击肌动蛋白。总体而言,状态变化似乎是通过将肌球蛋白的疏水三联体(Trp-546,Phe-547和Pro-548)连接到带有疏水导轨(Ile-341,Ile-345,Leu-349)的肌动蛋白导管而发生的。 ,以及Phe-352)以及随后的三重态沿轨道的线性运动。
  • 【使用时间脑电信号分解,以识别由事件编码理论提出的干扰物-反应结合的特定神经生理相关性。】 复制标题 收藏 收藏
    DOI:10.1016/j.neuroimage.2020.116524 复制DOI
    作者列表:Opitz A,Beste C,Stock AK
    BACKGROUND & AIMS: :The ability to cope with distracting information is a major requirement for goal-directed behavior. It is particularly challenged when distracting information is either potentially relevant or temporally close to goal-directed responses, resulting in so-called distractor-response bindings. According to the theory of event coding (TEC), distractor-response bindings should be reflected by processes in the event file, but not in object file (which stores stimulus features) or the action file (which stores response features). But even though the predictions of this theory are quite elaborated, their electrophysiological underpinnings and the associated functional neuroanatomical structures have remained largely elusive. To examine this, we used a distractor-response binding paradigm in combination with temporal EEG signal decomposition (RIDE) and source localization techniques. We showed that distractor-response binding effects are exclusively evident in the N450 time window of the central C-cluster. Source reconstructions revealed that distractor-response binding effects were associated with brain regions involved in updating internal representations by using task-relevant information to decide on response execution (temporo-parietal junction, BA40), alongside with brain regions involved in conflict resolution processes (right middle frontal gyrus, BA8). Our results suggest that RIDE can be used to dissociate binding processes from stimulus- and response-related processes. On top of this, the results of EEG decomposition match the key assumption of the TEC, that distractor-response bindings occur in event files, but not in object files or action files. The results show how cognitive-theoretical frameworks, such as the TEC, can directly be mapped onto the underlying neurophysiological processes using EEG signal decomposition.
    背景与目标: :应付分散注意力的信息的能力是目标导向行为的主要要求。当分散注意力的信息可能潜在相关或在时间上接近于目标导向的响应时,尤其会受到挑战,从而导致所谓的分散注意力-响应约束。根据事件编码(TEC)的理论,干扰项-响应绑定应由事件文件中的过程反映,但不能在目标文件(存储刺激特征)或动作文件(存储响应特征)中反映。但是,即使对该理论的预测进行了详尽的阐述,但它们的电生理基础和相关的功能神经解剖结构仍然难以捉摸。为了检查这一点,我们结合了临时性脑电信号分解(RIDE)和源定位技术,使用了干扰项-响应绑定范式。我们表明,干扰素反应的结合作用在中央C团簇的N450时间窗口中是唯一明显的。来源重构显示,干扰物-反应结合作用与大脑区域有关,该区域通过使用任务相关信息来决定响应执行(颞上顶交界处,BA40),从而与更新内部表征有关,大脑区域与冲突解决过程中涉及的大脑区域(右)中额回,BA8)。我们的结果表明,RIDE可用于将结合过程从刺激和反应相关过程中分离出来。最重要的是,EEG分解的结果与TEC的关键假设相符,即干扰项-响应绑定发生在事件文件中,而不是在目标文件或动作文件中。结果表明,如何使用EEG信号分解将认知理论框架(例如TEC)直接映射到潜在的神经生理过程。
  • 13 Vasomodulation of skeletal muscle BOLD signal. 复制标题 收藏 收藏

    【骨骼肌BOLD信号的血管调节。】 复制标题 收藏 收藏
    DOI:10.1002/jmri.20690 复制DOI
    作者列表:Bulte DP,Alfonsi J,Bells S,Noseworthy MD
    BACKGROUND & AIMS: PURPOSE:To evaluate whether the BOLD signal from skeletal muscle can be modulated by exercise and ingestion of vasoactive substances. MATERIALS AND METHODS:The right calf muscles of healthy adult volunteers were imaged using a GE 1.5-Tesla scanner and a gradient-echo sequence with spiral readout. Time-varying changes in the BOLD signal were induced through cyclic phases of normoxia (90 seconds of 20.8% O2) and hyperoxia (45 seconds of 100% O2 at 22 L/minute). Superimposed on this paradigm were pre- and post-exercise regimes, with and without ingestion of caffeine (100 mg) or antihistamine (4 mg chlorpheniramine). The numbers of voxels within slow-twitch (soleus) and fast-twitch (gastrocnemius) muscles that significantly responded to the paradigms were scored and compared using the AFNI software (NIMH). RESULTS:Cycling-inspired O2 produced a corresponding BOLD modulation that increased in magnitude with exercise. Chlorpheniramine significantly (P<0.01) prevented the overall increase in exercise-induced soleus muscle BOLD signal, while caffeine accentuated the increase (P<0.05) in the gastrocnemius relative to control (no vasomodulator) conditions. CONCLUSION:BOLD signal changes with exercise can be modulated by standard doses of chlorpheniramine (antihistamine) and caffeine. We suggest that chlorpheniramine may act detrimentally on slow-twitch muscle contractility, while caffeine appears to improve fast-twitch muscle function.
    背景与目标: 目的:评估骨骼肌的BOLD信号是否可以通过运动和摄入血管活性物质来调节。
    材料与方法:使用GE 1.5-Tesla扫描仪和带有螺旋读数的梯度回波序列对健康成人志愿者的右小腿肌肉成像。 BOLD信号的时变变化是通过常氧(90秒的20.8%O2)和高氧(45秒的100%O2在45 L下以22 L / min)的循环阶段引起的。在运动前和运动后的治疗方案中均叠加了这种模式,可以摄入或不摄入咖啡因(100毫克)或抗组胺药(4毫克氯苯那敏)。使用AFNI软件(NIMH)对慢肌(比目鱼肌)和快肌(腓肠肌)中对范例有明显反应的体素数进行评分和比较。
    结果:受自行车启发的氧气产生了相应的BOLD调节,随着运动强度的增加。氯苯那敏显着(P <0.01)阻止了运动引起的比目鱼肌BOLD信号的总体增加,而咖啡因则使腓肠肌相对于对照(无血管调节剂)的情况增加(P <0.05)。
    结论:运动后大胆信号的变化可通过标准剂量的扑尔敏(抗组胺剂)和咖啡因来调节。我们建议氯苯那敏可能对慢抽搐的肌肉收缩有害,而咖啡因似乎可以改善快抽搐的肌肉功能。
  • 【ELF3编码在拟南芥PHYB信号转导途径中起作用的昼夜节律调节的核蛋白。】 复制标题 收藏 收藏
    DOI:10.1105/tpc.13.6.1293 复制DOI
    作者列表:Liu XL,Covington MF,Fankhauser C,Chory J,Wagner DR
    BACKGROUND & AIMS: :Many aspects of plant development are regulated by photoreceptor function and the circadian clock. Loss-of-function mutations in the Arabidopsis EARLY FLOWERING 3 (ELF3) and PHYTOCHROME B (PHYB) genes cause early flowering and influence the activity of circadian clock-regulated processes. We demonstrate here that the relative abundance of the ELF3 protein, which is a novel nucleus-localized protein, displays circadian regulation that follows the pattern of circadian accumulation of ELF3 transcript. Furthermore, the ELF3 protein interacts with PHYB in the yeast two-hybrid assay and in vitro. Genetic analyses show that ELF3 requires PHYB function in early morphogenesis but not for the regulation of flowering time. This suggests that ELF3 is a component of a PHYB signaling complex that controls early events in plant development but that ELF3 and PHYB control flowering via independent signal transduction pathways.
    背景与目标: :植物发育的许多方面都受感光器功能和昼夜节律的调节。拟南芥早花3(ELF3)和PHYTOCHROME B(PHYB)基因中的功能丧失突变引起早期开花并影响昼夜节律调节的活动。我们在这里证明ELF3蛋白的相对丰度,这是一种新型的核定位蛋白,显示了昼夜节律调节,其遵循昼夜节律积累ELF3转录本的模式。此外,ELF3蛋白在酵母双杂交检测中和体外与PHYB相互作用。遗传分析表明,ELF3在早期形态发生中需要PHYB功能,但不需要调节开花时间。这表明ELF3是PHYB信号复合物的一个组成部分,该复合物控制植物发育中的早期事件,但ELF3和PHYB通过独立的信号转导途径控制开花。
  • 【编码中央多嘌呤束和转录后调控元件的慢病毒载体提供增强的转导和转基因表达。】 复制标题 收藏 收藏
    DOI:10.1089/104303401750214311 复制DOI
    作者列表:Barry SC,Harder B,Brzezinski M,Flint LY,Seppen J,Osborne WR
    BACKGROUND & AIMS: :Incorporation of a central polypurine tract (cPPT) and a posttranscriptional regulatory element (PRE) into lentivirus vectors provides increased transduction efficiency and transgene expression. We compared the effects of these elements individually and together on transduction efficiency and gene expression, using lentivirus vectors pseudotyped with vesicular stomatitis virus G protein (VSV-G) and encoding enhanced green fluorescent protein (GFP) and rat erythropoietin (EPO). The transduction efficiency was greater than 2-fold higher in the vector containing the PRE element, 3-fold higher in vector encoding the cPPT element, and 5-fold increased in the GFP virus containing both cPPT and PRE elements relative to the parent virus. In comparison with parent vector the mean fluorescence intensity (MFI) of GFP expression was 7-fold higher in cells transduced with virus containing PRE, 6-fold increased in cells transduced with virus containing cPPT, and 42-fold increased in GFP-virus containing both cPPT and PRE elements. EPO-virus containing a PRE element showed a nearly 5-fold increase in EPO secretion over the parent vector, and the vector encoding both PRE and cPPT showed a 65-fold increase. Thus, lentivirus vectors incorporating both PRE and cPPT showed expression levels significantly increased over the sum of the components alone, suggesting a synergistic effect.
    背景与目标: 将慢病毒载体整合到中央多嘌呤区(cPPT)和转录后调控元件(PRE)中,可提高转导效率和转基因表达。我们使用伪装了水泡性口炎病毒G蛋白(VSV-G)并编码增强型绿色荧光蛋白(GFP)和大鼠促红细胞生成素(EPO)的慢病毒载体,比较了这些元素单独以及一起对转导效率和基因表达的影响。相对于亲本病毒,在含有PRE元素的载体中,转导效率高出2倍,在编码cPPT元素的载体中,转导效率高出3倍,在同时含有cPPT和PRE元素的GFP病毒中,转导效率提高了5倍。与亲代载体相比,用含PRE的病毒转导的细胞中GFP表达的平均荧光强度(MFI)高7倍,用含cPPT的病毒转导的细胞中GFP表达的平均荧光强度高6倍,而在含cPPT的病毒转导的细胞中GFP表达的平均荧光强度增加42倍。 cPPT和PRE元素。含有PRE元件的EPO病毒的EPO分泌量比亲本载体增加了近5倍,而编码PRE和cPPT的载体均表现出了65倍的增加。因此,掺有PRE和cPPT的慢病毒载体显示表达水平明显高于单独组分的总和,表明具有协同作用。

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