Eukaryotic chromatin consisting of nucleosomes connected by linker DNA is organized into higher order structures,which is facilitated by linker histone H1.Formation of chromatin compacts and protects the genome,but al...Eukaryotic chromatin consisting of nucleosomes connected by linker DNA is organized into higher order structures,which is facilitated by linker histone H1.Formation of chromatin compacts and protects the genome,but also hinders DNA transactions.Cells have evolved mechanisms to modify/remodel chromatin resulting in chromatin states suitable for genome functions.The high mobility group box(HMGB)proteins are non-histone chromatin architectural factors characterized by one or more HMGB motifs that bind DNA in a sequence nonspecific fashion.They play a major role in chromatin dynamics.The Saccharomyces cerevisiae(yeast hereafter)HMGB protein Hmo1 contains two HMGB motifs.However,unlike a canonical HMGB protein that has an acidic C-terminus,Hmo1 ends with a lysine rich,basic,C-terminus,resembling linker histone H1.Hmo1 exhibits characteristics of both HMGB proteins and linker histones in its multiple functions.For instance,Hmo1 promotes transcription by RNA polymerases I and II like canonical HMGB proteins but makes chromatin more compact/stable like linker histones.Recent studies have demonstrated that Hmo1 destabilizes/disrupts nucleosome similarly as other HMGB proteins in vitro and acts to maintain a common topological architecture of genes in yeast genome.This minireview reviews the functions of Hmo1 and the underlying mechanisms,highlighting recent discoveries.展开更多
目的:探讨补血生髓方对肿瘤相关性贫血(cancer related anemia, CRA)小鼠的改善作用及可能的作用机制。方法:C57BL/6雌性小鼠腹腔注射苯肼(50mg/kg),并且皮下接种肺癌LLC细胞建立CRA模型,随机分成模型组、EPO组(1365IU/kg)、补血生髓方...目的:探讨补血生髓方对肿瘤相关性贫血(cancer related anemia, CRA)小鼠的改善作用及可能的作用机制。方法:C57BL/6雌性小鼠腹腔注射苯肼(50mg/kg),并且皮下接种肺癌LLC细胞建立CRA模型,随机分成模型组、EPO组(1365IU/kg)、补血生髓方组(60.67g/kg),每组10只,另取10只正常小鼠作为空白组,给药2周。ELISA检测促红细胞生成素、血清干扰素-γ(interferon-γ,IFN-γ)水平,流式细胞术检测外周血Tregs细胞比例,Real time-PCR及免疫荧光检测缺氧诱导因子-1α(hypoxia inducible factor-1α,HIF-1α)、程序性死亡-配体1(programmed cell death ligand 1,PD-L1)mRNA及蛋白的表达。结果:与模型组相比,补血生髓方组小鼠的肿瘤体积、肿瘤质量均显著降低(P<0.01)。与空白组相比,模型组血红蛋白、促红细胞生成素、IFN-γ水平显著下调(P<0.01),外周血Tregs细胞比例显著升高(P<0.05)。与模型组相比,补血生髓方组血红蛋白、促红细胞生成素、IFN-γ水平显著上调(P<0.01),外周血Tregs细胞比例显著下降(P<0.01),HIF-1α、PD-L1mRNA和蛋白表达显著降低(P<0.01)。结论:补血生髓方能够改善CRA小鼠的贫血状态,通过下调HIF-1α/PD-L1通路调节CRA小鼠的免疫功能,从而抑制肿瘤的生长。展开更多
目的观察人脐带间充质干细胞(HUMSC)对糖尿病肾病大鼠肾脏缺氧诱导因子(HIF-1α)表达的影响。方法50只健康清洁级8周龄雄性SD大鼠,随机选取20只为健康对照组,其余30只采用链脲菌素复制糖尿病肾病大鼠模型(模型组),两组大鼠饲养12周。第1...目的观察人脐带间充质干细胞(HUMSC)对糖尿病肾病大鼠肾脏缺氧诱导因子(HIF-1α)表达的影响。方法50只健康清洁级8周龄雄性SD大鼠,随机选取20只为健康对照组,其余30只采用链脲菌素复制糖尿病肾病大鼠模型(模型组),两组大鼠饲养12周。第12周,随机选取两组大鼠各3只分别尾静脉注射DiR-HUMSCs,代谢12~16 h后在小动物活体光学3D成像系统下观察DiR-HUMSCs在大鼠体内的分布。随机选取9只模型组大鼠进行HUMSCs移植(HUMSCs移植组)。HUMSCs移植采用尾静脉注射方式移植浓度为1×10^(6)个/mL HUMSCs 500μL至大鼠体内,每周1次,连续4周,共28 d。检测3组大鼠的24 h尿蛋白定量(24 h UPro)、血清肌酐(Scr)、血尿素氮(BUN)、尿肌酐(Ucr)、尿白蛋白与肌酐比值(UACR)水平;酶联免疫吸附试验(ELISA)检测3组大鼠血清HIF-1α水平;采用PAS和Masson染色进行肾脏组织病理检测;免疫荧光法检测3组大鼠肾组织HIF-1α、Slc12A3和Aquaporin1蛋白的表达。结果移植HUMSCs治疗4周后,与健康对照组比较,模型组和HUMSCs移植组大鼠Ucr水平降低(P<0.05),Scr、24 h UPro、BUN、UCAR均升高(P<0.05);与模型组比较,HUMSCs移植组大鼠Ucr水平差异无统计学意义(P>0.05),Scr、24 h UPro、BUN、UCAR均降低(P<0.05)。糖尿病肾病大鼠病理损伤缓解,系膜增生和基底膜增厚改善,小管空泡变性减少,间质纤维化减轻。模型组大鼠血清HIF-1α水平较健康对照组升高(P<0.05),HUMSCs移植组血清HIF-1α水平较模型组下降(P<0.05)。与健康对照组比较,模型组大鼠肾脏远端小管中HIF-1α蛋白水平增加(P<0.05);HUMSCs移植组的HIF-1α蛋白水平较模型组降低(P<0.05)。模型组远端小管标记蛋白Slc12A3水平低于健康对照组(P<0.05),HUMSCs移植组Slc12A3水平较模型组升高(P<0.05)。HUMSCs移植组的Aquaporin1蛋白水平较模型组和健康对照组均降低(P<0.05)。糖尿病肾病大鼠近端小管中无HIF-1α表达。结论HIF-1α主要在糖尿病肾病大鼠肾脏远端小管表达,且HUMSCs可通过抑制HIF-1α的表达修复肾小管的损伤。展开更多
文摘Eukaryotic chromatin consisting of nucleosomes connected by linker DNA is organized into higher order structures,which is facilitated by linker histone H1.Formation of chromatin compacts and protects the genome,but also hinders DNA transactions.Cells have evolved mechanisms to modify/remodel chromatin resulting in chromatin states suitable for genome functions.The high mobility group box(HMGB)proteins are non-histone chromatin architectural factors characterized by one or more HMGB motifs that bind DNA in a sequence nonspecific fashion.They play a major role in chromatin dynamics.The Saccharomyces cerevisiae(yeast hereafter)HMGB protein Hmo1 contains two HMGB motifs.However,unlike a canonical HMGB protein that has an acidic C-terminus,Hmo1 ends with a lysine rich,basic,C-terminus,resembling linker histone H1.Hmo1 exhibits characteristics of both HMGB proteins and linker histones in its multiple functions.For instance,Hmo1 promotes transcription by RNA polymerases I and II like canonical HMGB proteins but makes chromatin more compact/stable like linker histones.Recent studies have demonstrated that Hmo1 destabilizes/disrupts nucleosome similarly as other HMGB proteins in vitro and acts to maintain a common topological architecture of genes in yeast genome.This minireview reviews the functions of Hmo1 and the underlying mechanisms,highlighting recent discoveries.
文摘目的观察人脐带间充质干细胞(HUMSC)对糖尿病肾病大鼠肾脏缺氧诱导因子(HIF-1α)表达的影响。方法50只健康清洁级8周龄雄性SD大鼠,随机选取20只为健康对照组,其余30只采用链脲菌素复制糖尿病肾病大鼠模型(模型组),两组大鼠饲养12周。第12周,随机选取两组大鼠各3只分别尾静脉注射DiR-HUMSCs,代谢12~16 h后在小动物活体光学3D成像系统下观察DiR-HUMSCs在大鼠体内的分布。随机选取9只模型组大鼠进行HUMSCs移植(HUMSCs移植组)。HUMSCs移植采用尾静脉注射方式移植浓度为1×10^(6)个/mL HUMSCs 500μL至大鼠体内,每周1次,连续4周,共28 d。检测3组大鼠的24 h尿蛋白定量(24 h UPro)、血清肌酐(Scr)、血尿素氮(BUN)、尿肌酐(Ucr)、尿白蛋白与肌酐比值(UACR)水平;酶联免疫吸附试验(ELISA)检测3组大鼠血清HIF-1α水平;采用PAS和Masson染色进行肾脏组织病理检测;免疫荧光法检测3组大鼠肾组织HIF-1α、Slc12A3和Aquaporin1蛋白的表达。结果移植HUMSCs治疗4周后,与健康对照组比较,模型组和HUMSCs移植组大鼠Ucr水平降低(P<0.05),Scr、24 h UPro、BUN、UCAR均升高(P<0.05);与模型组比较,HUMSCs移植组大鼠Ucr水平差异无统计学意义(P>0.05),Scr、24 h UPro、BUN、UCAR均降低(P<0.05)。糖尿病肾病大鼠病理损伤缓解,系膜增生和基底膜增厚改善,小管空泡变性减少,间质纤维化减轻。模型组大鼠血清HIF-1α水平较健康对照组升高(P<0.05),HUMSCs移植组血清HIF-1α水平较模型组下降(P<0.05)。与健康对照组比较,模型组大鼠肾脏远端小管中HIF-1α蛋白水平增加(P<0.05);HUMSCs移植组的HIF-1α蛋白水平较模型组降低(P<0.05)。模型组远端小管标记蛋白Slc12A3水平低于健康对照组(P<0.05),HUMSCs移植组Slc12A3水平较模型组升高(P<0.05)。HUMSCs移植组的Aquaporin1蛋白水平较模型组和健康对照组均降低(P<0.05)。糖尿病肾病大鼠近端小管中无HIF-1α表达。结论HIF-1α主要在糖尿病肾病大鼠肾脏远端小管表达,且HUMSCs可通过抑制HIF-1α的表达修复肾小管的损伤。