中波紫外线辐射对人表皮角质形成细胞核因子κB转录活性的影响

目的 探讨中波紫外线(UVB)辐射对表皮角质形成细胞核因子κB(NF-κB)转录活性的影响。方法 正常人表皮角质形成细胞取自健康儿童包皮,并培养于37℃、5%CO₂的培养箱中;以20、60和120 mJ/cm² UVB辐射培养细胞;分别提取UVB辐射0、2、24和48 h后角质形成细胞的全细胞蛋白、核蛋白和胞浆蛋白;免疫印迹方法检测分析全细胞蛋白和核蛋白的NF-κB/p65以及胞浆蛋白NF-κB抑制物(IκB-a)的动态变化;电泳迁移率变更分析(EMSA)方法检测分析NF-κB的转录活性。结果 UVB辐射可显著促进角质形成细胞总蛋白和核蛋白中NF-κB的蛋白表达(P<0.05),且表达量与辐射剂量成正比,UVB辐射后2 h即可有NF-κB的蛋白表达水平的升高。24 h后达高峰并持续高水平表达至48 h:不同剂量UVB辐射角质形成细胞后的不同时间,均可促进NF-κB转录活性:UVB辐射可显著抑制角质形成细胞胞浆IκB-a蛋白的表达(P<0.05)。结论 UVB辐射可显著促进角质形成细胞NF-κB的转录活性。     

中波紫外线诱导的人角质形成细胞凋亡与SSA/Ro抗原表达

目的 为明确紫外线对光敏感型皮肤型红斑狼疮的作用机制,光照后人角质形成细胞表面SSA/Ro抗原的形成机理及其在皮损形成中的作用。方法 用M154培养基体外培养角质形成细胞,经UVB照射后先用相差显微镜观察细胞形态学改变,并用原位末端标记法测定凋亡细胞的断裂DNA片段,同时用间接免疫荧光法测定角质形成细胞表达SSA/Ro抗原情况;然后分别用DNase、RNase、DNase+RNase消化,碘化丙啶复染。用ELISA法测定细胞上清液SSA/Ro抗原;小剂量UVB照射后的角质形成细胞与亲和纯化的SSA/Ro特异血清及正常人血清孵育,台盼蓝染色观察细胞活性。结果 不同剂量UVB(52.8mJ/cm²、105.6mJ/cm²、158.4mJ/cm²、200mJ/cm²、211mJ/cm²)照射后KC凋亡,表面有凋亡小泡,细胞核有断裂DNA缺口并表达SSA/Ro抗原,随UVB剂量的递增,凋亡和表达SSA/Ro抗原的细胞数增多。这种抗原位于凋亡细胞的凋亡小体中,表达于细胞表面的SSA/Ro抗原可在原位诱导补体杀伤,而在细胞上清液中未测到SSA/Ro抗原。结论 UVB照射角质形成细胞通过诱导角质形成细胞凋亡表达自身抗原SSA/Ro,该抗原并不释放到上清液中,在补体和相应抗体存在的情况下可引起细胞损伤。     

中波紫外线辐射剂量与HaCaT细胞凋亡时相的相关性研究

目的 探讨中波紫外线(UVB)辐射角质形成细胞后,UVB辐射剂量与角质形成细胞凋亡时相的相关性。方法 以20,40,60,80,100和120mJ/cm²的UVB辐射永生化人角质形成细胞株HaCaT细胞,检测辐射后2,12,24,48和72h的细胞活性和细胞周期的变化,以及代表不同时相的凋亡通路:即应用广谱Caspase抑制剂VAD-FMK与凋亡细胞中活化的Caspase不可逆的结合检测早期Caspase介导的凋亡;应用AnnexinV及PI双染方法检测后发的细胞膜介导的凋亡;以及应用DNA的梯度凝胶电泳检测晚期细胞核介导的凋亡。结果 UVB辐射可使HaCaT细胞的细胞周期受滞于G2/M期,G2/M期的百分比与辐射剂量成正比。细胞活性于24h后与辐射剂量成反比。各时相的凋亡率均与辐射剂量成正比,但凋亡通路有明显的时相性:即早期(48h内)由Caspase和细胞膜介导凋亡为主,晚期(48h后)则由细胞核介导凋亡为主。结论 UVB诱导的角质形成细胞凋亡具有显著的剂量与时相依赖性特征。宜对其进行多指标、多时相的检测。     

紫外线对HaCaT细胞结合珠蛋白mRNA表达的影响

目的 观察紫外线照射对人角质形成细胞系HaCaT细胞表达结合珠蛋白的影响。方法 用逆转录-聚合酶链反应法检测长波紫外线UVA、中波紫外线UVB照射后HaCaT细胞各时相结合珠蛋白mRNA表达水平。结果 UVA12J/cm²照射后HaCaT细胞结合珠蛋白mRNA表达明显升高。照射后20min结合珠蛋白mRNA表达已开始升高,6h达第一高峰,48h出现第二高峰。照射后2h、4h、6h、24h、48h组与对照组比较,差异有统计学意义(P<0.05)UVB30mJ/cm²照射HaCaT细胞后结合珠蛋白mRNA表达也出现时相变化:4h达第一高峰,48h出现第二高峰。照射后20min、2h、4h、6h、12h、48h、72h组与对照组比较,差异有统计学意义(P<0.05)。结论 紫外线UVA、311nmUVB上调HaCaT细胞结合珠蛋白mRNA表达,随照射时间,结合珠蛋白mRNA表达呈时相变化。     

核因子-κB反义寡核苷酸抑制紫外线诱导的HaCaT细胞反义分泌白介素6

目的 探讨核因子-κB(NF-κB)反义寡核苷酸转染体外培养的HaCaT细胞反义株HaCaT后,对紫外线(UV)诱导的HaCaT细胞反义分泌炎症因子白介素6(IL-6)的抑制作用。方法 蛋白质印迹方法测定不同剂量中波紫外线(UVB)辐射HaCaT细胞反义后NF-κBp65的变化;逆转录-聚合酶链反应测定NF-κBp65反义寡核苷酸转染后p65m RNA表达的变化;酶联免疫吸附测定法测定NF-κBp65反义寡核苷酸转染后紫外线辐射的HaCaT细胞反义分泌IL-6水平。结果 10、20、30mJ/cm² UVB辐照HaCaT细胞反义后均可显著促进NF-κBp65表达(P<0.05),不同浓度的NF-κBp65反义寡核苷酸转染后对30mJ/cm² UVB诱导的p65mRNA表达和IL-6分泌均有显著抑制作用(P<0.05)。结论 脂质体介导的NF-κBp65反义寡核苷酸转染HaCaT细胞反义,可以抑制UV辐射诱导的HaCaT细胞反义产生IL-6,表明UV诱导HaCaT细胞反义产生IL-6可能是通过UV激活NF-κBp65的表达产生的。     

中波紫外线激活HaCaT细胞炎症信号通路的实验研究

目的 探讨中波紫外线(UVB)对角质形成细胞(KC)炎症信号通路的影响.方法 UVB(40 mJ/cm²)照射永生化人角质形成细胞株HaCaT细胞,分别于照射后0、10、30、60、120、240min收集细胞蛋白和核蛋白,蛋白质印迹法检测NF-κB信号传导通路中的重要分子-磷酸化IκB-α(P-IκB-α)、IκB-α和NF-κB p65蛋白的动态变化,以及MAPK家族的蛋白分子ERK1/2、p38、c-JNK等磷酸化激活的动态变化.结果 蛋白质印迹法检测结果显示,UVB照射后0.5h IκB-α开始发生磷酸化和降解,在第2、4小时时更加明显;细胞核蛋白p65的量在照射后0.5h开始升高,在随后的2h时达到高峰.UVB照射后10 min HaCaT细胞内的ERK1/2、p38、c-JNK蛋白的磷酸化就开始增加.结论 UVB照射KC可激活细胞内的NF-κB及MAPK信号传导通路.     

羟氯喹及没食子酸酯对HaCaT细胞光照射的影响

目的 探讨羟氯喹和绿茶活性成分表没食子儿茶素没食子酸酯(EGCG)对中波紫外线(UVB)损伤永生化角质形成细胞株(HaCaT细胞)的保护作用及其机制。方法 采用UVB定时及定量照射培养的HaCaT细胞,分别加入羟氯喹和EGCG干预处理,以RT-PCR法检测各受试组p53、p21、c-fos基因表达水平。结果 UVB照射后可明显增加HaCaT细胞中p53,p21,c-fos mRNA表达,羟氯喹和EGCG可不同程度地下调上述基因表达水平。结论 羟氯喹和EGCG的光保护作用在HaCaT细胞可能与其抑制p53,p21,c-fos基因表达有关。     

表没食子儿茶素没食子酸酯减轻UVB诱导的朗格汉斯细胞凋亡作用

目的 研究中波紫外线(UVB)对人表皮朗格汉斯细胞(LC)的光损伤作用以及绿茶活性成分表没食子儿茶素没食子酸酯(EGCG)的光保护作用。方法 采用密度梯度离心和免疫磁珠的方法分离纯化人表皮LC,将分离纯化的LC随机分为对照组、30 mJ/cm² UVB辐射组以及辐射后加用200μg/mL EGCG处理组,4h后以PI染色并经流式细胞仪检测细胞凋亡率。结果 30 mJ/cm² UVB辐射组的凋亡率明显高于对照组,EGCG干预组的凋亡率低于单纯UVB辐射组,但仍高于非照射对照组;且辐射后S期细胞数明显增加。几乎没有G₂/M期的细胞,EGCG处理辐射细胞后,S期细胞数减少。结论 UVB可诱导人表皮LC凋亡,而EGCG具有一定的保护作用。     

p53蛋白在UVB诱导凋亡的富集表皮干细胞的角质形成细胞中的表达

目的研究p53蛋白在中波紫外线(ultraviolet lightB,UVB)诱导凋亡的富集表皮干细胞的角质形成细胞群中的表达情况。方法分离富集人表皮干细胞的角质形成细胞群和正常角质形成细胞群,使用UVB诱导两种细胞群凋亡,蛋白印迹法比较不同剂量UVB诱导前后两组细胞的p53蛋白表达的差异。结果两种细胞在不同剂量的UVB照射后p53蛋白表达均比照射前显著增加,在20mJ/cm2与40mJ/cm2照射剂量时,富集人表皮干细胞的角质形成细胞群p53蛋白表达高于正常角质形成的细胞群,差异有统计学意义(P<0.05)。结论富集人表皮干细胞的角质形成细胞p53蛋白表达比其它角质形成细胞对中波紫外线的照射易感。     

NB-UVB和阿维A对角质形成细胞肝素结合表皮生长因子样生长因子mRNA的影响

目的 探讨阿维A和窄谱中波紫外线(NB-UVB)对培养的正常人角质形成细胞增殖和肝素结合表皮生长因子样生长因子(HB-EGF)mRNA表达的影响.方法 用1μmol/L阿维A和/或100mJ/cm²NB-UVB处理正常人角质形成细胞12h后,用MTT法、RT-PCR和实时荧光定量RT-PCR法分别检测细胞增殖和HB-EGFmRNA表达的改变.结果 1μmol/L阿维A和100mJ/cm²NB-UVB单独作用时,均可抑制角质形成细胞的增殖和上调HB-EGFmRNA的表达,两者联合作用时,对角质形成细胞增殖的抑制和HB-EGFmRNA的诱导作用更强,分别为19.7%和8.6倍,之后依次为1μmol/L阿维A(14.4%,7.1倍)和100mJ/cm²NB-UVB(8.7%,2.5倍).结论 阿维A和/或NB-UVB处理后,可协同上调HB-EGF的表达,可能参与调节二者对角质形成细胞增殖的抑制作用.     

UV Induces GADD45 in a p53-Dependent and -Independent Manner in Human Keratinocytes

BACKGROUND: GADD45 is a multifunctional protein involved in DNA repair and in cell cycle checkpoint control. p53 plays an important role in regulating DNA repair and in response to UVB in keratinocytes. Objective: GADD45 and p53 expression was examined and compared at the mRNA and protein level after exposure to UV irradiation. METHODS: Human keratinocytes were exposed to increasing doses of UVB, and an RNA protection assay and a Western blot analysis were performed. RESULTS: The RNase protection assays using human keratinocytes showed that GADD45 mRNA increases after 4 h and remains elevated for 24 h in cells irradiated at 100, 300, or 600 J/m2 UVB. The level of GADD45 protein increases after 8 h and remains elevated for 48 h, with maximal induction at 300 J/m2. p53 mRNA did not rise in concert with GADD45 at any dose used, and p53 protein was not up-regulated at the lower dose of 100 J/m2. CONCLUSION: GADD45 is regulated in both a p53-dependent and a p53-independent manner in keratinocytes after UV exposure.     

Ultraviolet B-induced LGI3 secretion protects human keratinocytes

Leucine‐rich glioma inactivated 3 (LGI3) is known to be expressed mainly in the brain. However, the expression and physiological roles of LGI3 in skin cells remain unknown. In this study, it was found for the first time that LGI3 is expressed mostly by normal human keratinocytes. Furthermore, ELISA analysis showed that HaCaT human keratinocytes increased LGI3 secretion after exposure to ultraviolet B (UVB) in a time‐ and dose‐dependent manner. We next investigated the possible role of LGI3 in keratinocytes. LGI3 (50 ng/ml) increased survival of HaCaT cells by 20% after UVB irradiation (150 mJ/cm²). It was also found that LGI3 stimulates the phosphorylation of Akt, which is involved in the cell survival‐signalling cascade. Furthermore, LGI3 led to the phosphorylation of MDM2 and subsequent p53 degradation. Taken together, the data suggest that LGI3 may regulate p53 levels and that keratinocyte‐derived LGI3 may act as a novel cytokine for skin homoeostasis.     

Suberythemal ultraviolet B radiation alters the expression of cell cycle-related proteins in the epidermis of human subjects without leading to photoprotection

Background  Deregulation of the cell cycle proteins is one of the critical factors leading to cutaneous carcinogenesis.
Objectives  To monitor the expression of cell cycle proteins in the epidermis of subjects after repeated exposure to ultraviolet (UV) B radiation, and to test for the development of photoprotection by subsequent irradiation with a single erythemal UVB dose.
Methods  A total of 26 healthy volunteers were divided into four groups: group 1 ( n  =   9) were given whole-body UVB irradiation for 10 consecutive days with 0·7 minimal erythema dose (MED), group 2 ( n  =   9) were irradiated as in group 1 followed 24 h later by a single UVB dose of 3 MED on buttock skin, group 3 ( n  =   4) were irradiated with a UVB dose of 3 MED on buttock skin, and group 4 ( n  =   4) were not irradiated. Skin biopsies were collected 24 h after the final irradiation and stained for cyclins A, B1, D1, and p16, p18, p21, p27, p53, pRB, Bax and Bcl-2.
Results  The expression of cyclin D1, p18 and p21 was significantly higher in groups 1 and 2 compared with the nonirradiated group 4 controls and, in group 2, the expression of pRB, p53 and Bax was also increased. In group 3, only p53 and Bax proteins were significantly elevated compared with group 4. The expression of cyclin D1, p16, p18, p27, pRB and Bcl-2 was higher in group 2 compared with group 3.
Conclusions  Suberythemal UVB radiation was sufficient to cause changes in the expression of several epidermal cell cycle proteins. When tested by irradiation with a single erythemal UVB dose following the repeated exposures, no photoprotection against the UV-induced alteration in cell cycle protein expression was apparent.     

Opposing effects of ultraviolet B irradiation on interleukin-1 receptor antagonist and interleukin-1α messenger RNA expression in a human epidermoid carcinoma cell line

Interleukin-1 receptor antagonist (IL-1RA) is a cytokine that acts to antagonize IL-1 activity without agonist function. The expression of IL-1RA has been reported in many cell types, including the keratinocyte that covers the outer most part of the skin. However the modulation of IL-1RA by ultraviolet B (UVB), which is the most biologically active UV, has not been reported yet. We therefore selected a keratinocyte cell line with a cytokine-producing profile similar to that of keratinocytes and tested the effect of UVB on its ability to produce IL-1RA mRNA. IL-1RA mRNA was constitutively expressed in the cell line and began to be suppressed by 3 h after the UVB irradiation with 100 mJ/cm². The level of IL-1RA expression became lowest by 16 h after the irradiation with 100 mJ/cm². Simultaneously, IL-1α mRNA started to increase by 1 h and peaked by 3–16 h after the irradiation with 10–100 mJ/cm². The differential expression of IL-1α and IL-1RA mRNA following exposure to a high dose (100 mJ/cm²) of UVB may markedly potentiate the role of IL-1 in UV-induced inflammation.     

Differential effects of UV irradiation on nuclear retinoid receptor levels in cultured keratinocytes and melanocytes

A major risk factor for skin cancer is UV irradiation, which not only damages DNA and other photosensitive compounds like vitamin A, but may also perturb cellular signaling, e.g. via the retinoid receptor system believed to be important for cancer protection. We used cultured normal human keratinocytes and melanocytes to examine the effects of UV irradiation on the expression of the predominant retinoid receptors in the human skin (RARalpha, RARgamma and RXRalpha) and the AP-1 protein c-Jun; mRNA levels were studied by real-time PCR and protein levels by Western blot. In keratinocytes, a single dose of UVB (50 mJ/cm2) caused a rapid drop in the expression of all three receptors (mRNA levels minus 35-50% after 4 h; protein levels minus 20-45% after 8 h), which was followed over the next 40 h by a variable response, leading to full normalization for RARalpha only. In contrast, the levels of c-Jun did not change significantly after UV exposure. In melanocytes, UVB caused a similar drop of the retinoid receptor levels as in keratinocytes but this was soon followed by an increased expression leading to a complete normalization of all receptor levels within 1-3 days. The c-Jun levels in melanocytes increased 1 day after UV exposure and remained high (plus 50%) thereafter. In both cell types, a approximately 3-fold increase in apoptosis (measured by DNA fragmentation) was observed 8-48 h after UVB irradiation. In conclusion, a depletion of vitamin A and retinoid receptors by UV irradiation, together with unchanged or even increased c-Jun levels, might seriously interfere with retinoid signaling and thus promote future tumor development, especially in keratinocytes.     

中波紫外线对角质形成细胞MMP-1及TIMP-1的影响

目的：研究中波紫外线照射对永生化人角质形成细胞的影响。方法：绘制细胞生长曲线,用不同剂量UVB（30、60、90 mJ/cm2）照射永生化人角质形成细胞,用MTT方法测定UVB照射后细胞的增殖活性,用RT-PCR方法测定HaCaT细胞中MMP-1mRNA和TIMP-1mRNA的表达。结果：UVB照射后,HaCaT细胞的增殖活性受到抑制,MMP-1 mRNA表达增强,TIMP-1 mRNA表达下降,90 mJ/cm2照光组与未照光组比较,差异均有统计学意义。结论：UVB照射可诱导HaCaT细胞损伤和细胞凋亡,促使MMP-1mRNA表达增加,TIMP-1 mRNA表达减少,二者比例失调,这可能与光老化的发生有一定的关系。     

Ultraviolet B irradiation increases keratin 5 and keratin 14 expression through epidermal growth factor receptor of SV40-transformed human keratinocytes

Keratin intermediate filaments are heteropolymers composed of type I and type II keratins. Ultraviolet B (UVB) irradiation induces keratin expression by keratinocytes. Using SV40-transformed human keratinocytes (SVHK), we investigated the effect of UVB irradiation on keratin expression. UVB irradiation (10 mJ/cm(2)) increased keratin 5 and keratin 14 mRNAs and proteins without affecting cell viability. Upregulation of keratin 5 and keratin 14 was dependent on the dose of radiation: the effect was observed at 5 mJ/cm(2) and the maximal effect was observed at 10 mJ/cm(2). Higher UVB doses (more than 10 mJ/cm(2)) were cytotoxic. Expression of keratin 1 and keratin 10 was marginal in SVHK and was not affected at either the mRNA or protein level by UVB. The stimulatory effects on keratin 5 and keratin 14 expression were also observed in cultured normal human keratinocytes (NHK) and HaCaT keratinocytes. The tyrosine kinase inhibitor, genistein, and the epidermal growth factor (EGF) receptor inhibitor, AG1429, significantly suppressed the increase in expression of keratin 5 and keratin 14 by SVHK. In contrast, the suppressive effect was not observed with the protein kinase C inhibitor, H-7. Furthermore, pretreatment with neutralizing anti-EGF receptor antibody also suppressed UVB-induced keratin 5 and keratin 14 expression by SVHK, NHK and HaCaT cells. UVB irradiation did not affect the steady-state expression of TGF-alpha by SVHK. Immunoprecipitation and immunohistochemical studies revealed that UVB irradiation induced EGF receptor activation in the absence of EGF and TGF-alpha. These results indicate that UVB increases keratin 5 and keratin 14 expression through direct activation of the EGF receptor in SVHK.