白藜芦醇对LPS诱导的MC3T3-E1成骨细胞的骨保护作用

目的 探讨白藜芦醇对脂多糖(LPS)诱导的MC3T3-E1成骨细胞的骨保护作用.方法 采用CCK-8法检测白藜芦醇不同浓度下MC3T3-E1成骨细胞的细胞增殖活性,对硝基苯磷酸盐法检测白藜芦醇不同浓度下MC3T3-E1成骨细胞ALP活性.将MC3T3-E1成骨细胞分为空白组(基础培养基)、对照组(LPS 2 μg/mL)和实验组(LPS 2μg/mL+白藜芦醇20 μmol/L).采用qRT-PCR检测三组成骨相关基因Runx2、ALP、骨钙素(OCN)和骨桥蛋白(OPN)mRNA表达,Western blot法检测三组细胞沉默调节蛋白1(SIRT1)蛋白表达.结果 白藜芦醇20 μmol/L是MC3T3-E1成骨细胞最适成骨浓度(P＜0.05).与空白组比较,实验组成骨相关基因Runx2、ALP、OCN和OPN mRNA表达水平和SIRT1蛋白表达水平均降低(P＜0.05);与对照组相比,实验组成骨相关基因Runx2、ALP、OCN和OPN mRNA表达水平和SIRT1蛋白表达水平升高(P＜0.05).结论 白藜芦醇能够通过提高Runx2、ALP、OCN、OPN和SIRT1相关成骨因子的表达对LPS诱导的MC3T3-E1成骨细胞发挥骨保护作用.     

葛根素对MC3T3-E1细胞增殖、分化和矿化及TRPM3 mRNA表达的影响

目的观察葛根素对小鼠成骨细胞MC3T3-E1细胞增殖、分化和矿化及TRPM3 mRNA表达的影响。方法分别采用CCK-8法、碱性磷酸酶(ALP)活性、茜素红染色测定葛根素对MC3T3-E1细胞增殖、成骨分化、矿化作用的影响。流式细胞术检测葛根素对MC3T3-E1细胞周期及细胞内钙离子浓度的影响。RT-PCR检测葛根素对TRPM3基因m RNA表达的影响。结果 0.1、1、10μmol·L~(-1)葛根素能明显促进MC3T3-E1细胞增殖,使G1期细胞比例减少,G_2+S期细胞比例增加,其中0.1μmol·L~(-1)浓度效果最为明显;与正常对照组相比较,0.1μmol·L~(-1)葛根素组细胞的ALP活性和矿化结节面积均明显提高;0.1μmol·L~(-1)葛根素组细胞的TRPM3 m RNA表达水平和细胞内钙离子浓度明显降低。结论葛根素可促进MC3T3-E1细胞的增殖、分化和矿化,可降低TRPM3 mRNA表达水平和细胞内钙离子浓度。     

鹿茸胶原酶解物对地塞米松诱导成骨细胞MC3T3-E1凋亡的保护作用

目的研究鹿茸胶原酶解物(VCH)作为治疗药物对地塞米松(DEX)所致MC3T3-E1细胞损伤的影响,探究VCH对糖皮质激素性骨质疏松的保护作用。方法分别用不同浓度的VCH处理成骨细胞MC3T3-E1,MTT法测定细胞活力,通过AnnexinⅤ-FITC/PI双染流式细胞术检测细胞凋亡率,实时PCR及Western印迹检测MC3T3-E1细胞分化相关因子的m RNA及蛋白表达水平。结果 VCH 0.3 g·L~(-1)作用于MC3T3-E1细胞48 h以后能显著促进MC3T3-E1细胞的增殖;VCH可促进骨细胞的活性,可上调成骨细胞分化的标志蛋白ALP的表达和转录,可明显减少DEX所诱导的MC3T3-E1细胞凋亡(P<0.05)。结论 VCH抑制糖皮质激素引起成骨细胞凋亡,促进骨形成,为骨质疏松症的防治提供理论依据。     

丹参素对地塞米松诱导MC3T3-E1成骨细胞损伤的保护作用

目的 探讨丹参素对地塞米松诱导MC3T3-E1成骨细胞损伤的保护作用。方法 构建地塞米松1μmol/L诱导MC3T3-E1成骨细胞损伤模型;其中,C、D、E组分别采用丹参素10、20、40μmol/L预处理。另设空白对照组(A组)和地塞米松1μmol/L模型对照组(B组)。MTT法检测细胞存活率,二硝基苯肼法和流式细胞术分别检测乳酸脱氢酶(LDH)和活性氧(ROS)水平,Western blot检测p21、核因子E2相关因子2(Nrf2)和血红素氧合酶1(HO-1)蛋白水平。检测丹参素40μmol/L预处理小干扰RNA沉默p21表达(F组)后地塞米松1μmol/L诱导MC3T3-E1成骨细胞(G组)的细胞存活率以及Nrf2和HO-1蛋白水平。结果 与A组比较,B、C、D、E组细胞存活率降低,LDH和ROS水平升高,且p21、Nrf2和HO-1蛋白表达水平升高(P<0.05)。与B组比较,C、D、E组细胞存活率和p21、Nrf2和HO-1蛋白表达水平呈丹参素浓度依赖性升高,而LDH和ROS水平降低(P<0.05)。G组细胞存活率高于B组,但低于E组(P<0.05)。G组...     

二甲双胍通过激活自噬促进MC3T3-E1细胞系成骨分化的研究

目的探讨二甲双胍通过激活自噬促进MC3T3-E1细胞系成骨分化的作用。方法用含有不同浓度二甲双胍的成骨诱导剂处理MC3T3-E1细胞,其中二甲双胍的浓度分别为0(对照)、200、400、800μmol/L。利用碱性磷酸酶(ALP)染色检测二甲双胍促进MC3T3-E1细胞成骨的最适浓度,采用免疫印迹法(Western blotting)和免疫荧光法检测自噬相关蛋白,并选择出二甲双胍的最佳干预浓度。对照组、二甲双胍400μmol/L组、二甲双胍400μmol/L+3-甲基腺嘌呤(3-MA,5 mmol/L)组和3-MA 5 mmol/L组分别干预MC3T3-E1细胞4 h后,采用Western blotting法、免疫荧光法、透射电镜检测自噬指标,并利用ALP染色、半定量RT-PCR和Western blotting检测成骨能力。结果二甲双胍能够剂量相关性地促进MC3T3-E1细胞的ALP活性,并且400μmol/L二甲双胍是促进MC3T3-E1细胞成骨的最适浓度。二甲双胍0(对照)、200、400μmol/L组的LC3 Ⅱ/Ⅰ比值逐渐增大,P62/β-actin比值逐渐减小,LC3荧光强度逐渐增强;800μmol/L二甲双胍组的LC3 Ⅱ/Ⅰ值减小,P62/β-actin比例增大,LC3荧光强度下降;且与对照组比较,400μmol/L二甲双胍组的LC3Ⅱ/Ⅰ比值明显增大,P62/β-actin比值明显降低(P0.05),LC3荧光强度最强。与对照组比较,二甲双胍400μmol/L组中LC3 Ⅱ/Ⅰ的比值增大,P62蛋白表达减少(P0.05),LC3荧光强度增强,自噬体数量增多;ALP活性增强,成骨相关基因和蛋白OCN,COL1的表达增强(P0.001、0.05、0.01)。二甲双胍中加入3-MA 5 mmol/L后,LC3 Ⅱ/Ⅰ的比值减小,P62蛋白表达增多,LC3荧光强度减弱,自噬体数量减少;ALP活性减弱,成骨相关基因和蛋白OCN,COL1的表达减弱。结论二甲双胍能通过激活MC3T3-E1细胞系的适度自噬促进其成骨分化。     

异槲皮苷对MC3T3-E1成骨细胞增殖与分化的影响作用

目的研究异槲皮苷对体外培养MC3T3-E1成骨细胞增殖、分化的影响作用。方法以细胞矿化结节染色鉴定MC3T3-E1成骨细胞株骨矿化功能,以MTT法测定成骨细胞的增殖率,以试剂盒法测定细胞内碱性磷酸酶(ALP)的活性。结果在终浓度为1.08×10-6mol·L-1、1.08×10-7mol·L-1、1.08×10-8mol·L-1时,异槲皮苷能极显著促进MC3T3-E1成骨细胞增殖(P<0.01);终浓度为1.08×10-6mol·L-1时,异槲皮苷作用96h后能极显著提高细胞内ALP的活性(P<0.01)。结论一定浓度的异槲皮苷能够显著促进MC3T3-E1成骨细胞增殖和分化。     

瑞香素通过PI3K/AKT和BMP/Smad信号通路保护糖皮质激素诱导的成骨细胞增殖和分化抑制研究

目的 探讨瑞香素对地塞米松诱导的成骨细胞增殖和分化抑制的作用及分子机制.方法 体外培养MC3T3-E1细胞,分为对照组、地塞米松组、地塞米松+瑞香素40μmol/L组、地塞米松+瑞香素60μmol/L组和地塞米松+瑞香素80μmol/L组;采用CCK-8试剂盒测定细胞活力;RT-PCR法测量细胞中碱性磷酸酶(Alkal...     

高糖环境中吡格列酮对MC3T3-E1成骨细胞的作用及其机制

目的观察高糖环境下吡格列酮对MC3T3-E1成骨细胞的作用并探讨其可能机制。方法高糖(22.5 mmol·L~(-1))环境培养MC3T3-E1细胞,分为对照组,吡格列酮2.5、5、10μmol·L~(-1)组,干预24、48 h。检测细胞增殖活性、凋亡率、骨钙素和碱性磷酸酶(ALP)分泌水平,以及过氧化物酶体增殖物激活受体γ(PPARγ)、成骨因子runt相关基因2(Runx2)和骨形态蛋白2(BMP-2)mRNA的表达水平。并分析PPARγ、Runx2的表达与骨钙素、ALP、BMP-2的相关性。结果在相同干预时限,吡格列酮各组MC3T3-E1成骨细胞增殖活性、骨钙素和ALP的分泌水平、Runx2 mRNA和BMP-2 mRNA的表达均低于对照组,凋亡率和PPARγmRNA的表达高于对照组(P<0.05)。随吡格列酮浓度增加,细胞增殖活性、骨钙素和ALP的分泌、Runx2 mRNA和BMP-2 mRNA的表达均降低,而细胞凋亡率和PPARγmRNA的表达增高(P<0.05)。与干预24 h相比,干预48 h时相同浓度吡格列酮组细胞增殖活性,骨钙素和ALP的分泌水平,PPARγ、Runx2、BMP-2 mRNA的表达或无变化或略增加。结论高糖环境下吡格列酮对成骨细胞有损害作用,促进PPARγ表达、抑制Runx2的表达可能为其作用机制之一。     

葛根素对成骨细胞增殖能力及靶向Runx2的miRNA的影响

目的研究葛根素作用成骨细胞MC3T3-E1后对细胞的增殖能力和靶向Runx2基因的miRNA的影响。方法 1MTT法检测葛根素作用于MC3T3-E1细胞后对成骨细胞增殖能力的影响。2碱性磷酸酶活性检测葛根素对于成骨细胞活力影响。3葛根素作用于成骨细胞后,采用荧光实时定量PCR(Q-PCR)和蛋白印迹法(Western blot)法检测Runx2的mRNA表达水平和蛋白表达水平。4采用Target Scan、Pic Tar等靶点预测软件预测靶向Runx2的miRNA,并与表达谱测定的葛根素作用MC3T3-E1前后miRNA变化作比较。5采用Q-PCR法验证葛根素作用MC3T3-E1前后靶向Runx2基因的miRNA表达量。6构建Runx2 3'UTR/突变型Runx2 3'UTR重组质粒、合成miRNA-204mimics、miRNA-204inhibitor、miRNA-204NC共转染MC3T3-E1细胞,用双荧光素酶报告基因系统验证Runx2与miRNA-204的靶向关系。结果葛根素作用后,与空白对照组比较,细胞增殖活性提高,Runx2的mRNA和蛋白表达水平上升,miRNA-204和miRNA-344f-5p表达水平下降,miRNA-2861表达水平上升,miRNA-23a-5p、miRNA-770-5p、miRNA-871-5p表达水平无明显改变。细胞转染48h后,只有Runx2 3'UTR+miRNA-204 mimics组荧光素蛋白的表达水平明显降低,说明只有miRNA-204可抑制Runx2 3'UTR报告基因的表达。结论葛根素可促进成骨细胞增殖,并通过下调靶向Runx2的miRNA的表达来提高Runx2表达水平。     

天料木中异香豆素糖苷化合物对MC3T3-E1细胞增殖、分化及OPG/RANKL/RANK信号通路的影响

目的 探讨天料木中异香豆素糖苷化合物4-hydroxy-2-{[（benzoyl） oxy]methyl}phenyl-β-D-glucopyranoside-6-benzoate （HPGB）对小鼠胚胎成骨细胞MC3T3-E1细胞活性的影响及其作用机制。方法 体外培养MC3T3-1细胞,用不同浓度的异香豆素糖苷化合物进行干预,采用MTT法测定MC3T3-1细胞增殖情况,碱性磷酸酶（ALP）测定细胞分化情况,悬液芯片技术检测、分析糖蛋白Dickkop （DKK-1）、骨保护素（OPG）、骨桥蛋白（OPN）、骨钙素（BGP）和核因子-κB受体活化因子配体（RANKL）蛋白表达水平。Real-time PCR法检测、分析DKK-1、RANKL mRNA的表达水平。结果 异香豆素糖苷化合物在3~300 μmol/L可促进MC3T3-E1细胞增殖和分化能力,具有浓度相关性;与正常对照组相比,异香豆素糖苷化合物可提高MC3T3-E1的ALP活性。蛋白结果表明,异香豆素糖苷化合物可显著上调MC3T3-E1细胞中OPG、OPN的表达,DKK-1、RANKL蛋白表达无明显变化,但显著提高了OPG/RANKL值。同时,mRNA结果显示异香豆素糖苷化合物可显著上调MC3T3-E1细胞中OPG mRNA表达,显著提高OPG/RANKL值。结论 异香豆素糖苷化合物可通过上调OPG、OPN的表达、提高OPG/RANKL值,促进MC3T3-E1的增殖和分化。     

3-二甲胺基-3-苯基丙醇的制备

苯甲醛和丙二酸经Knoevenagel缩合、NaBH4-I2体系还原得3-氨基-3-苯基丙醇，再经Eschweiler-Clark反应制得3-二甲胺基-3-苯基丙醇，总收率29％。     

Analysis of γβ, βγ, γγ, ββ continuous turns in proteins

Abstract: We report the observation of continuous turns in proteins which comprise individual γ‐turns or β‐turns or both that are situated immediately one after the other along the polypeptide chain. The continuous turns were identified from a representative data set of three‐dimensional protein crystal structures. The γβ/βγ, γγ and ββ continuous turns represent peptides of varying amino acid residue lengths and conformations. The continuous turns frequently observed in proteins were: γβ, between a coil and a strand; βγ, between a helix and a strand; γγ, between coils; and ββ, either between a strand and a coil or between strands or coils. We determined the statistically significant amino acid residue preferences at individual positions in the turn, calculated amino acid positional potentials and analyzed main chain hydrogen bonds and side‐chain interactions likely to stabilize the continuous turns. The data on continuous turns have been integrated in the database of structural motifs in proteins (DSMP) on our web server at ( http://www.cdfd.org.in/dsmp.html ). This is useful to make queries on sequences compatible with different continuous turns.     

Analysis of γβ, βγ, γγ, ββ multiple turns in proteins

Abstract: The number of γ‐turns in a representative protein dataset selected from the current Protein Data Bank has increased almost seven times during the past decade. Eighty percent classic γ‐turns and 57% inverse γ‐turns are associated as multiple turns with either another γ‐turn or a β‐turn. We refer to these as multiple turns of the (γβ)_1,2,3 or (βγ)_1,2,3 type, depending upon whether the γ‐turn is before or after the β‐turn along the protein chain, respectively. However, for multiple turns involving only γ‐turns, we follow the nomenclature analogous to that proposed earlier for the multiple (or double) β‐turns. Fifty‐eight per cent β‐turns are associated as multiple turns with another β‐turn. We extracted multiple turns from the protein dataset and classified them on the basis of individual γ‐ or β‐turn types and the number of overlapping residues. Furthermore, we evaluated the amino acid positional potentials and determined the statistically significant amino acid preferences, hydrogen bond/side‐chain interaction preferences in the multiple turns and secondary structure preferences for residues immediately flanking these turns. The results of our analysis would be useful in the modeling, prediction or design of multiple turns in proteins. The amino acid sequence corresponding to the multiple turn, position in the protein chain, PDB Code/chain in which multiple turn is present and the individual turn types constituting the multiple turns are available from our website and this information would also be integrated in our Database of Structural Motifs in Proteins ( http://www.cdfd.org.in/dsmp.html ).     

3',3'-Difluoro-3'-deoxythymidine: comparison of anti-HIV activity to 3'-fluoro-3'-deoxythymidine.

3',3'-Difluoro-3'-deoxythymidine (3) has been synthesized in four steps from thymidine, and characterized by 1H NMR and NOE experiments. The JHF coupling constants support a conformation in solution that is predominantly 2'-endo (S). Although conformationally and sterically nucleoside 3 may resemble other thymidine analogs which are active against HIV-1, 3 is virtually inactive.     

Synthese von γ,γ'-Dihydroxysulfonen und γ-Hydroxy-γ'-ketosulfonen

Syntheses of γ,γ'-Dihydroxysulfones and γ-Hydroxy-γ'-ketosulfones Reduction of γ,γ'-diketosulfones 1 with dimethylaminoborane leads to γ,γ'-dihydroxysulfones 3 via γ-hydroxy-γ'-ketosulfones 2 . The influence of substituents on the ratio of the yields of 2 and 3 is investigated.     

Mutagenicity of 3-nitrodibenzofuran and 3-aminodibenzofuran

Mutagenicities of 3-nitrodibenzofuran and 3-aminodibenzofuran were examined using Salmonella typhimurium TA98 and TA100. Strong mutagenicity was found in both compounds. The mutagenic potency of 3-nitrodibenzofuran was approximately 3.5-fold stronger in TA98 and twice stronger in TA100 than that of benzo[a]pyrene. Mutagenicity of 3-aminodibenzofuran was observed under metabolic activation and was 10 times stronger in TA98 and about 5 times stronger in TA100 than that of benzo[a]pyrene.