维甲酸诱导的脊柱裂小鼠的脊髓全基因组表达谱分析(英文)

关于维甲酸胚胎病理学的研究很多,维甲酸受体在器官发生、发育及神经管闭合过程中发挥重要作用。但维甲酸影响这些过程的机制还不清楚。在本研究中,我们发现,小鼠怀孕8天时,给予母体连续3次维甲酸灌胃,将导致胎儿脊柱裂,发生率为96.77%。本研究应用微阵列技术,在维甲酸诱导的脊柱裂小鼠胎儿的脊髓组织中发现了134个差异表达在1.5倍以上的基因。基因富集分析显示,母亲暴露于维甲酸导致的胎儿脊柱裂,与促凋亡和抗凋亡、细胞增殖、迁徙、细胞骨架成分以及细胞或局部粘附等基因功能簇相关,提示这些细胞成分和生物学的功能缺陷促使脊柱发育异常。我们的研究提供了脊柱裂的全基因组基因表达模式,有助于理解神经管缺陷的病因和病理学。     

RARα mRNA和RARβ mRNA在过量RA致神经管畸形发生中的表达

目的探讨过量RA对金黄地鼠胚胎神经管RARα和RARβ mRNA表达的影响。方法采用原位杂交及图像分析,半定量分析正常及RA致畸金黄地鼠胚胎神经管中RARα和RARβ mRNA表达水平的变化。结果过量RA可使RARα和RARβ mRNA在金黄地鼠神经管中的表达水平呈现短时下降,随后又大幅上升的变化。结论过量RA引起的RARα和RARβ mRNA表达水平的变化与RA致金黄地鼠神经管畸形相关。     

维甲酸信号通路的生物学进展

本文阐述了受维甲酸信号调控的基因表达多样性的分子机制,描述了维甲酸受体的特征、维甲酸反应元件的多态性、转录中介因子包括辅活化因子和辅抑制因子在维甲酸受体介导的转录调控中的作用,主要的维甲酸应答基因及维甲酸在肿瘤治疗中的应用。     

α1,3-岩藻糖基转移酶Ⅶ转染对全反式维甲酸诱导的人肝癌细胞凋亡的影响

式维甲酸诱导细胞凋亡,α1,3 FucT-Ⅶ的过量表达使凋亡细胞数量明显增多,caspase-3的活性和细胞骨架F-actin的破坏均增高,抑制剂DEVD-CHO可明显抑制细胞凋亡,但F-actin的破坏程度并未得到改善.通过caspase-3通路转染α1,3 FucT-Ⅶ增加了肝癌细胞对全反式维甲酸诱导的凋亡的敏感性,从而为肝癌的防治提供了实验依据.     

维甲酸β受体在肿瘤中表达的研究进展

对维甲酸抑制肿瘤细胞生长的机制研究中,发现维甲酸β受体（RARβ）起关键作用。本文着重阐述了RARβ生物学性质,RARβ在肿效率 的表达状况及由RARβ介导的抑制肿瘤细胞生长的作用和机制。     

神经管畸形的表观遗传学研究进展

神经管畸形(neural tube defects,NTDs)是胚胎在早期发育过程中,由于神经管闭合不全或障碍引起的一组以脑和(或)脊髓发育异常为主的先天畸形。目前,对于神经管畸形的发病机制和病因没有明确的定论。很多因素参与神经管畸形的发生,主要涉及遗传、环境、以及二者的相互作用。遗传因素的研究主要着重于寻找神经管畸形的致病基因并进行基因功能缺陷研究,但是神经管畸形是多因素参与的结果,基因功能缺陷研究并不能完全解释其发病机制。基于目前的研究现状,近年来,环境因素通过调控表观遗传的修饰进而参与调节NTDs发生相关基因表达的研究逐渐受到重视。     

过表达CD82对植入期小鼠子宫内膜整合素αV、β3、E-cadherin和β-catenin表达的影响

目的探讨CD82对着床窗口期小鼠子宫内膜上皮细胞内整合素αV、β3、E-cadherin以及β-catenin蛋白表达的影响。方法将构建的CD82腺病毒转染原代培养的小鼠子宫内膜上皮细胞。检测妊娠小鼠子宫内膜上皮细胞转染CD82腺病毒后,细胞内整合素αV、β3、E-cadherin和β-catenin的表达变化情况。结果提取的上皮细胞纯度为(93.2±0.6)%。构建的CD82腺病毒转染效率达到(92.0±4.5)%,转染原代培养的小鼠子宫内膜上皮细胞24 h后,RT-PCR检测发现CD82基因表达明显升高。转染48 h后,Western blot检测CD82蛋白水平明显升高。免疫细胞化学检测妊娠第4天的小鼠子宫内膜上皮细胞转染CD82腺病毒后,整合素αV、β3以及β-catenin的表达较未转染组均有明显上升(P0.05),但E-cadherin的表达量无明显变化(P0.05)。结论胚胎植入前,CD82可能影响小鼠子宫内膜上皮细胞内整合素αV、β3和β-catenin的蛋白表达。     

转化生长因子beta在热应激导致小鼠神经管畸形发生中的表达

本研究旨在探讨热应激致神经管畸形（NTDs）中转化生长因子beta（TGF-beta）的表达情况。选用昆明小鼠40只,实验组20只小鼠于妊娠后8．5天（E8．5）在42℃温箱中喂养30分钟,进行热应激处理,建立小鼠胚胎NTDs模型。对照组不处理。11．5d取胎鼠,通过体视显微镜和组织学切片观察实验组和对照组神经管发育情况,计算神经管畸形发生率;     

Wnt信号分子在神经管缺陷（NTD）发生过程中的表达及其可能的作用机制

目的探讨Wnt信号分子在神经胚形成和神经管缺陷（NTD）发生过程中的作用及其可能的分子调控机制。方法用Western blot方法半定量检测正常及NTD小鼠胚胎的脑泡及脊髓神经组织中Wnt信号分子的变化。采用流式细胞技术检测正常和神经管缺陷（NTD）胚胎脑泡及脊髓神经组织神经上皮细胞周期动力学的变化。结果与正常胚胎的脑泡及脊髓神经组织比较,NTD胚胎的脑泡及脊髓神经组织的β-catenin蛋白表达量明显减弱;而GSK-3β蛋白表达量明显增强。流式细胞仪的检测结果显示：与正常E10.5d胚胎脑泡及脊髓神经组织的神经上皮相比,神经管缺陷模型胚胎的脑泡及脊髓神经组织的神经上皮细胞处于G0/G1期的细胞百分比明显增高,而神经上皮细胞处于S期的细胞百分比则明显降低。结论神经管缺陷的发生与Wnt信号途径的变化是密切相关的,Wnt信号分子的变化可能正是神经管缺陷形成中细胞增殖抑制的相关分子机制。神经管上皮细胞的增殖抑制及凋亡可能是NTD发生的重要细胞基础。     

维甲酸对斑马鱼中枢神经系统及软骨发生的影响

脂溶性的维甲酸可通过固醇类激素作用途径启动ＨＯＸ族及ＬＩＭ族调节基因,进而影响脊椎动物胚胎的形态发生、再生组织的分化。本文通过不同浓度系列表明,维甲酸对早期鱼胚发育的影响程度依赖于其作用浓度与作用时间,１０＾－６￣１０＾－７Ｍ的浓度范围为作用敏感区。维甲酸对中枢神经系统前后轴上的影响尤其显著,主要表现为小头畸形、无眼或无心脏。作者首次用Ｂｒｄｕ－Ａｎｔｉ－Ｂｎｄｕ标记处于Ｓ期的细胞核表明,ＲＡ作用     

Expression of retinoic acid receptor genes in neural crest-derived cells during mouse facial development

Retinoic acid (RA) is known as a teratogen that induces abnormalities in facial structures which are made up mainly of neural crest-derived mesenchyme. We investigated expression patterns of RA receptor (RAR) genes (subtypes alpha, beta, gamma) during mouse facial development. The expression of the RAR beta gene is specific for the mesenchyme around developing eyes and nose, whereas the RAR gamma gene is expressed in the mesenchyme differentiating to facial cartilages and bones. In contrast, the RAR alpha gene is expressed weakly and uniformly over the facial region. These results suggest that crucial roles of endogenous RA in facial development depend on differential functions of the RAR subtypes.     

Altered expression of retinoic acid (RA) receptor mRNAs in the fetal mouse secondary palate by all-trans and 13-cis RAs: implications for RA-induced teratogenesis

Retinoic acid (RA) is mandatory for various biological processes and normal embryonic development but is teratogenic at high concentrations. In rodents, one of the major malformations induced by RA is cleft palate (CP). RA mediates its effects by RA receptors (RARs), but the expression patterns of RARs in the developing palate are still unclear. We investigated the normal expression of RAR alpha, beta, and gamma messenger RNAs (mRNAs) in the fetal mouse secondary palate and the effects of all-trans and 13-cis RAs on the expression of RAR mRNAs by Northern blot analysis. RAR alpha (2.8, 3.8 kb), RAR beta (3.3 kb), and RAR gamma (3.7 kb) mRNAs were detected in the fetal palate on gestational days (GD) 12.5-14.5. The expression of RAR alpha and gamma mRNAs did not show apparent sequential changes, but that of RAR beta mRNA increased at GD 13.5. Treatment of pregnant mice with 100 mg/kg all-trans RA induced CP in 94% of the fetuses and elevated the levels of RAR beta and gamma mRNAs in the fetal palate. The up-regulation of RAR beta mRNA by all-trans RA was more marked than that of RAR gamma mRNA. Treatment with 100 mg/kg 13-cis RA induced CP in only 19% of the fetuses. Although 13-cis RA elevated the RAR beta and gamma mRNA levels in fetal palates, its up-regulation was slower and less marked than that induced by all-trans RA. These findings indicate that the induction of RAR beta mRNA in the fetal palate correlates well with the tissue concentration of all-trans RA after RA treatment, and RAR beta may be one of the most influential candidate molecules for RA-induced teratogenesis.     

Modulation by retinoids of mRNA levels for nuclear retinoic acid receptors in murine melanoma cells

Retinoids inhibit the growth and enhance the differentiation of murine S91-C2 melanoma cells. Specific alterations in gene expression are a plausible mechanism for these effects. Since nuclear retinoic acid receptors (RAR) are likely mediators of retinoid-induced changes in gene expression, we used Northern blotting to analyze the expression of RAR alpha, RAR beta, and RAR gamma in S91-C2 cells. mRNA for both RAR alpha and RAR gamma was detected in these cells, but no RAR beta mRNA could be found. Treatment with 10(-7) and 10(-6) M beta-all-trans-retinoic acid (RA) for 24 h caused a 1.5- to 2-fold increase in RAR alpha and RAR gamma mRNA, whereas lower concentrations of RA were ineffective. RAR beta mRNA, which was undetectable in untreated cells, was detected after 24 h of treatment with a RA concentration as low as 10(-9) M, and its level increased with up to 10(-6) M RA. At the latter dose, RAR beta mRNA induction occurred by 4 h and increased progressively, reaching a plateau after 24 h of treatment. RAR beta mRNA induction at 4 h was not inhibited by cycloheximide at a concentration that suppressed protein synthesis by more than 90%. Several retinoids and related synthetic compounds, including 13-cis RA, TTNPB, Ch55, Am80, and the trifluoromethyl nonyloxyphenyl analog of RA, also induced RAR beta mRNA, whereas a 24-h treatment with 10(-6) M retinol, TTNP (a decarboxylated analog of TTNPB), or the phenyl analog of RA failed to induce RAR beta mRNA. With the exception of retinol and the trifluoromethyl nonyloxyphenyl analog of RA, the ability of the retinoids to induce RAR beta mRNA and their growth inhibitory effect were correlated. However, S91-C154, a RA-resistant mutant subclone derived from S91-C2 cells, showed mRNA levels of RAR alpha and RAR gamma and induction of RAR beta by RA similar to those detected in the sensitive S91-C2 cells. Like the S91 melanoma cells, two other mouse melanoma cell lines, K-1735P and B16-F1, constitutively expressed RAR alpha and RAR gamma mRNAs. The level of RAR beta mRNA was increased by RA only in B16-F1 cells, although the growth of both was inhibited by RA. These results demonstrate that RA can, directly and rapidly, induce the expression of mRNA for a high affinity nuclear receptor in some murine melanoma cells and that this induction is not sufficient to inhibit growth.     

Aggregation and cell cycle dependent retinoic acid receptor mRNA expression in P19 embryonal carcinoma cells.

Differentiation of P19 EC cells along different pathways into derivatives resembling cells of the three embryonic germ layers is accompanied by characteristic differences in modulation of expression of each of the three retinoic acid receptor genes, RAR alpha, -beta and -gamma. Differentiation induced by addition of RA to P19 EC cells cultured in monolayer is accompanied by a rapid increase in expression of both RAR alpha and -beta. Induction of RAR beta occurs in a characteristic biphasic manner, suggesting that multiple factors and/or different mechanisms are involved in controlling its expression. RAR beta mRNA is induced to a far higher level during early aggregation in the presence of RA than during early differentiation in monolayer, suggesting that the direction of differentiation depends on the number and/or ratio of alpha and beta type of RA receptors. Aggregation of P19 EC cells in the presence of RA, but not DMSO, is accompanied by repression of RAR gamma, suggesting that the expression of RAR beta and RAR gamma during neuroectodermal differentiation is mutually exclusive. The effects of RA on RAR expression are significantly greater in G1 than in S-phase of the cell cycle. These results extend previous observations that commitment to differentiation is cell cycle dependent and indicates that critical target gene regulation in response to RA has to take place in G1 for differentiation to occur.