Mechanisms and Prevention of Skin Photoaging

皮肤老化是一个复杂、多因素所致的过程,其结果是皮肤弹性和功能发生改变。引起皮肤老化的原因包括内源性(如年龄等)和外源性(如紫外线等)因素,后者所致的皮肤老化即皮肤光老化。本文以国外文献为基础,着重介绍皮肤光老化的发生机制,描述与之相关的主要信号通路,总结皮肤光老化的预防措施,以指导进一步的研究。Skin aging is a very complicated process with many factors involved, which will lead to changes in skin elasticity and functions.Skin aging can be triggered by both intrinsic(e.g., age) and extrinsic(e.g., ultraviolet light) factors.The latter is also called skin photoaging.This paper reviewed the mechanisms of photoaging and related prevention approaches based on international literature.It also described the major signaling pathways involved in the process of photoaging so as to inform further studies.国家自然科学基金青年项目(编号:81101562); 广东省科技计划项目(编号:2012B060300005); 广东省自然科学基金面上项目(编号:S2012010009633

Pregnane X receptor involves in the effect of aflatoxin B1 on necroptosis in human normal L02 liver cells

目的初步探讨孕烷X受体(PXr)对黄曲霉毒素b1(Afb1)诱导肝细胞dnA损伤和坏死性凋亡的影响。方法采用已构建的PXr高表达l02-PXr和空白载体对照l02-P b细胞;实时荧光定量PCr(Q rT-PCr)检测细胞nr1I2和CyP3A4 M rnA水平改变;蛋白免疫印迹(WESTErn blOTTIng)检测细胞内PXr和坏死性凋亡下游效应自噬分子lC3-Ⅰ和lC3-Ⅱ蛋白相对表达含量;双核微核试验(CbMn)检测细胞遗传损伤情况;采用噻唑蓝(MTT)法测定Afb1对细胞活性抑制影响;利用坏死性凋亡抑制剂nEC-1构建坏死性凋亡抑制的细胞模型,验证Afb1诱导的坏死性凋亡的效应。结果与l02-P b细胞相比,l02-PXr细胞nr1I2 M rnA和PXr蛋白显著上调(均P<0.001)。Afb1显著地诱导l02-P b和l02-PXr细胞中CyP3A4 M rnA上调(均P<0.05),在l02-PXr细胞中的效应更为明显。与对照组相比,Afb1在5~30μMOl/l呈剂量反应关系诱导l02-P b和l02-PXr细胞的微核率增高(均P<0.05),l02-PXr细胞更为明显;同时,Afb1明显地诱导两株细胞的核芽率和核桥率,但随Afb1剂量增高都有下降趋势。细胞活性随Afb1浓度(1.875~120μMOl/l)增加呈剂量反应关系抑制(均P<0.05);且相对于l02-P b细胞,l02-PXr细胞对Afb1处理48 H诱导的细胞活性抑制作用更为敏感(P<0.05)。nEC-1可显著性抑制Afb1诱导的l02-PXr细胞活性抑制率(P<0.05),然而却不能降低Afb1诱导l02-P b细胞活性抑制率。此外,Afb1显著性诱导l02-P b和l02-PXr坏死性凋亡下游lC3-Ⅱ的上调(均P<0.05);且与l02-P b细胞相比,nEC-1对Afb1诱导的l02-PXr细胞活性抑制和lC3-Ⅱ上调的抑制效果更为明显(P<0.05)。结论 PXr参与Afb1诱导人肝细胞dnA损伤介导的坏死性凋亡,与PXr促进Afb1诱导CyP3A4基因上调有关。Objective To investigate the effects of pregnane X receptor(PXR) over expression on aflatoxin B1(AFB1)-induced DNA damage and necroptosis in human normal liver L02 cells.Methods The established cells models of stable transfection of over expression PXR(L02-PXR) and null vector p Babe-puro(L02-p B) were used.The background levels of NR1I2 m RNA and PXR protein, and the expression of AFB1-induced CYP3A4 m RNA and LC3-I / LC-3II protein were determined by the real time PCR(q RT-PCR) and Western blotting, respectively.The cytokinesis-block micronucleus(CBMN)assay was adopted to evaluate the genotoxicity.The cell viability inhibition rate was determined by MTT assay, after treatment with different doses of AFB1.The inhibition models of necroptosis were established by treatment with necroptosis inhibitor Nec-1.Results The expression of NR1I2 m RNA and PXR protein in L02-PXR cells were higher than that in L02-p B cells(all P<0.001).The level of CYP3A4 m RNA was significantly up regulated in L02-p B and L02-PXR cells by treatment with AFB1(all P<0.05).Compared with control group(Ctrl), MN frequencies in L02-p B and L02-PXR cells were significantly increased by treatment with AFB1 in a dose-dependent manner(all P <0.05), especially, in L02-PXR cells.Meanwhile, NBD and NBP frequencies were significantly increased by treatment with AFB1.However, AFB1 with a higher dose induced downward trends in frequencies of NBD and NBP.Moreover, the inhibition rate of cell viability was increased after treatment with AFB1(1.875~120 μmol / L) in a dose-dependent manner(all P <0.05); specifically, the inhibitory effects of AFB1-treatment after 48 h were significantly stronger in L02-PXR cells than in L02-p B cells(P <0.05).Interestingly, necroptosis inhibitor Nec-1 could inhibit AFB1-induced cell death in L02-PXR cells(P<0.05).On the contrary, Nec-1 could not prevent L02-p B cells from death by treatment with AFB1.In addition, the expression of necroptotic LC3-II, a classical marker of autophagy, was significantly increased by treatment with AFB1 in two cell lines(all P <0.05).Notably, pre-treatment with Nec-1 was able to block the inducement of necroptotic LC3-II in a more efficiently way in L02-PXR cells than in L02-p B cells(P <0.05).Conclusion PXR involved in the effect of AFB1 on necroptosis by DNA damage mediation in human liver cells;specifically, the up regulation of CYP3A4 gene may relate to the AFB1-induced DNA damage.国家自然科学基金(81172705;81072334); 广东省自然科学基金(S2011020002769); 福建省自然科学基金(2014J01372

Effects of cadmium on promoter methylation and transcriptional level of PPP2R1A gene in hepatocytes

目的分析镉染毒处理肝细胞中蛋白磷酸酶2A(PP2A)-Aα支架亚基基因PPP2r1A启动子区甲基化状态及其转录水平的改变。方法采用永生化人正常肝l02细胞及肝细胞癌HEP g2细胞为研究对象,对其进行以下分组和处理:1低、中和高剂量氯化镉(Cd Cl2)处理组,分别予浓度为20.0、40.0和60.0μMOl/l Cd Cl2处理24 H;2低、中和高剂量5-氮杂-2’-脱氧胞苷(5-AzA-d C)处理组,分别予浓度为2.5、5.0和10.0μMOl/l 5-AzA-d C处理48 H;3 5-AzA-d C组予浓度为5.0μMOl/l的5-AzA-d C处理48 H,Cd Cl2组予浓度为40.0μMOl/l的Cd Cl2处理24 H,(5-AzA-d C+Cd Cl2)组予浓度为5.0μMOl/l的5-AzA-d C预处理48 H后再予浓度为40.0μMOl/l Cd Cl2处理24 H;4 Cd Cl2处理组予浓度为40.0μMOl/l Cd Cl2处理24 H。上述4种分组均设对照组,予等体积生理氯化钠溶液或二甲基亚砜处理。经1~3处理后的细胞采用实时荧光定量聚合酶链反应(PCr)检测PPP2r1A、金属硫蛋白1b(MT1b)和dnA甲基转移酶3A(dnMT3A)的MrnA转录水平(以对照组水平为1.00)。经4处理后的细胞采用亚硫酸氢盐修饰后PCr扩增PPP2r1A启动子区克隆测序检测CP g岛的甲基化情况。结果 l02细胞和HEP g2细胞中,不同剂量Cd Cl2处理组PPP2r1A MrnA转录水平随镉处理剂量增高呈剂量依赖性下降(P0.05)。结论外源化学物Cd Cl2可诱导肝细胞中PPP2r1A转录水平降低,可能与镉能够引起目的基因启动子区甲基化状态改变有关,提示PP2A亚基基因的表观遗传学调控可影响镉诱导的肝细胞功能。Objective To analyze the effects of cadmium on the promoter methylation and transcriptional level of protein phosphatase 2A( PP2A)-Aα supported subunit gene PPP2R1 A gene in hepatocytes.Methods The immortalized human fetal liver cell line L02 and the hepatocellular carcinoma cell line Hep G2 were selected as the research objects: 1 Cells were treated with low-,medium- and high-dose( 20.0,40.0 and 60.0 μmol / L) cadmium chlorid( Cd Cl2) for 24 h.2Cells were treated with low-,medium- and high-dose( 2.5,5.0 and 10.0 μmol / L) 5-aza-2'-deoxycytidine( 5-Aza-d C)for 48 h.3 Cells were given 5.0 μmol / L for 48 h in 5-Aza-d C group,cells were exposed to 40.0 μmol / L Cd Cl2 for 24 h in Cd Cl2 group and cells were exposed to 40.0 μmol / L Cd Cl2 for 24 h after 48 h pretreatment of 5.0 μmol / L 5-Aza-d C in( 5-Aza-d C + Cd Cl2) group.4 Cells were treated with 40.0 μmol/L Cd Cl2 for 24 h in Cd Cl2 group.The above groups were all given the controls with the same volumes of physiological sodium chloride solution or dimethyl sulfoxide.Real-time fluorescent quantitative polymerase chain reaction( PCR) detection was used to detect the mRNA transcriptional levels of PPP2R1 A,Metallothionein 1B( MT1B),DNA methyltransferase 3A( DNMT3A) after treatments 1-3.After treatment4,cloning sequencing was used to detect the Cp G island methylation status of PPP2R1 A promoter after bisulfite sequencing PCR.Results In L02 and Hep G2 cells,the transcriptional levels of PPP2R1 A mRNA in Cd Cl2 group were decreased in a dose-dependent manner( P 0.05).Conclusion It was indicated the Cd Cl2 could lead to the transcription inhibition of PPP2R1 A,and the effect may be related with the change of its promoter methylation status.These data showed epigenetic regulation of PP2 A subunit genes may affect the function of hepatocytes exposed to cadmium.国家自然科学基金(81172705;81072334;81130052); 广东省自然科学基金重点项目(S2011020002769

Preventive effect and mechanisms of 3,3-diindolylmethane on oxidative stress induced by hydrogen peroxide in HaCaT cells

目的:探究3,3'-二吲哚甲烷(dIM)对过氧化氢(H_2O_2)诱导人角质形成细胞(HACAT)氧化应激作用的预防效应及可能机制。方法:体外培养HACAT细胞,用H_2O_2建立氧化应激模型。采用CCk-8法检测不同浓度(1~20μMOl/l)dIM对HACAT细胞生长的抑制作用;流式细胞术检测dIM作用前后细胞内活性氧自由基(rOS)含量的变化;WESTErn blOT检测不同浓度dIM(0、5、10μMOl/l)对HACAT氧化应激相关蛋白核因子(nf-κb)和丝裂原活化蛋白激酶(MAPkS)磷酸化表达水平的影响。结果:成功建立了HACAT氧化应激模型。CCk-8法研究结果显示1-10μMOl/l dIM对HACAT细胞无明显毒性作用(P>0.05);流式细胞术检测结果表明10μMOl/l dIM预处理可有效预防由H_2O_2诱导的HACAT内rOS产生(P0.05).Flow cytometry results indicated that pretreatment with DIM(10 μmol/L) could inhibit the level of intracellular ROS(P<0.05).With increasing concentration of DIM,the levels of p-p38-MAPK,p-JNK and p-NF-κB were significantly depressed.CONCLUSION:DIM could protect HaCaT cells from H_2O_2-induced oxidative stress via suppressing production of ROS levels and down-regulating the expression of NF-κB and members of MAPKs.DIM might be used as an effective drug to treat or reduce oxidative stressmediated injury in skin cells.国家自然科学基金青年基金(81101562); 广东省科技计划项目(2012B060300005); 广东省自然科学基金(S2012010009633

大连极紫外相干光源

先进光源的发展在前沿科学研究中发挥的作用越来越重要。近十年来,飞速发展的自由电子激光技术为科学家们提供了探索未知世界、发现新科学规律和实现技术变革的重要工具。建成的大连极紫外(EUV)相干光源的运行波段为50~150nm,单脉冲能量大于100μJ,且可提供10-12 s和10-13 s量级的超快激光脉冲,是我国第一台自由电子激光用户装置,并且是国际上唯一运行在极紫外波段的自由电子激光用户装置,在世界范围内为用户提供具有高峰值亮度和超短脉冲的极紫外激光。大连EUV相干光源是由国家自然科学基金委资助、由中国科学院大连化学物理研究所和上海应用物理研究所共同承担的重大科学仪器研制项目,目标是打造一个以先进极紫外光源为核心、主要用于能源基础科学研究的光子科学平台