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Journal of Pharmacology And Experimental Therapeutics Fast Forward
First published on July 18, 2005; DOI: 10.1124/jpet.105.088674


0022-3565/05/3152-624-630$20.00
JPET 315:624-630, 2005
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CELLULAR AND MOLECULAR

Prevention of the Ultraviolet B-Mediated Skin Photoaging by a Nuclear Factor {kappa}B Inhibitor, Parthenolide

Kiyotaka Tanaka, Junichi Hasegawa, Kaori Asamitsu, and Takashi Okamoto

Department of Molecular and Cellular Biology, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan (K.T., J.H., K.A., T.O.); and Department of Research and Development, Ichimaru Pharcos Co., Ltd., Motosu, Japan (K.T.)

Received April 28, 2005; accepted July 15, 2005.


    Abstract
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 Abstract
 Materials and Methods
 Results
 Discussion
 References
 
The skin photoaging is characterized by keratinocyte hyperproliferation and degradation of collagen fibers, causing skin wrinkling and laxity and melanocyte proliferation that leads to pigmentation. UV is considered to be a major cause of such skin changes. It is well established that nuclear factor {kappa}B (NF-{kappa}B) is activated upon UV irradiation and induces various genes including interleukin-1 (IL-1), tumor necrosis factor {alpha} (TNF{alpha}), and matrix metalloprotease-1 (MMP-1). It is also known that basic fibroblast growth factor (bFGF) production is induced by UV and promotes the proliferation of skin keratinocytes and melanocytes. We found that UVB, IL-1, and TNF{alpha} induced NF-{kappa}B activation and then produced MMP-1 and bFGF in HaCaT keratinocytes and skin fibroblasts. In this experiment, we examined if parthenolide, an NF-{kappa}B inhibitor, could block the UVB-mediated skin changes. We found that parthenolide could effectively inhibit the gene expression mediated by NF-{kappa}B and the production of bFGF and MMP-1 from cells overexpressing p65, a major subunit of NF-{kappa}B. We also found that parthenolide could inhibit the UVB-induced proliferation of keratinocytes and melanocytes in the mouse skin. These findings suggest that NF-{kappa}B inhibitors should be useful for the prevention of skin photoaging.


Skin aging is a complex process that involves intrinsic and exogenous causes. Although intrinsic skin aging is associated with other physiological processes and is inevitable, exogenous aging is caused by extrinsic harmful environments and can be prevented. UV is one of the most noxious factors among the harmful environments (Ulrich et al., 2004Go). UV irradiation induces inflammatory processes in the skin, and the irradiated skin becomes metabolically hyperactive associated with epidermal hyperproliferation and accelerated collagen fiber breakdown. In contrast, physiologically aged skin is usually characterized by a slow decline in many of these processes (Kligman, 1989Go). The UV-irradiated skin is characterized by fine and coarse wrinkling, roughness, dryness, laxity, and pigmentation (Chung, 2003Go). Microscopically, these changes can be explained by keratinocyte hyperproliferation and degradation of collagen fibers (Brenneisen et al., 2002Go), causing skin wrinkling and laxity, and melanocyte proliferation that leads to pigmentation characterized by dysregulation of melanocyte homeostasis and increase in the melanocyte density (Hirobe et al., 2003Go). The UV-induced production of proinflammatory cytokines, such as interleukin-1 (IL-1) and tumor necrosis factor {alpha} (TNF{alpha}), has been considered attributable to these changes (Corsini et al., 1997Go; Yarosh et al., 2000Go). Similarly, induction of matrix metalloprotease-1 (MMP-1) is responsible for the degradation of collagen fibers (Wlaschek et al., 1994Go; Barchowsky et al., 2000Go). In addition, UV irradiation is known to stimulate both keratinocytes and fibroblasts to induce basic fibroblast growth factor (bFGF) that is responsible for the proliferations of melanocytes and keratinocytes.

It is well established that a transcription factor, nuclear factor {kappa}B (NF-{kappa}B), is activated upon UV irradiation and induces various genes including IL-1 and TNF{alpha}, which subsequently stimulate the signal transduction pathway to activate NF-{kappa}B, thus conforming a vicious cycle (Okamoto et al., 1997Go; Saliou et al., 1999Go). In fact, NF-{kappa}B is known to increase MMP-1 in dermis (Bond et al., 1999Go; Sun et al., 2002Go; Chung, 2003Go). It is also reported that UV irradiation induces bFGF production (Sabourin et al., 1993Go), presumably through NF-{kappa}B activation (Wakisaka et al., 2002Go). Thus, inhibition of the NF-{kappa}B activation pathway would block the vicious cycle elicited by UV irradiation and effectively prevent the UVB-mediated cutaneous alterations.

NF-{kappa}B is sequestrated in the cytoplasm as an inactive complex with a class of inhibitory molecules known as inhibitor {kappa}B (I{kappa}B). Treatment of cells with a variety of inducers such as IL-1 and TNF-{alpha} results in phosphorylation, ubiquitination, and degradation of the I{kappa}B proteins (Hayden and Ghosh, 2004Go). The phosphorylation of I{kappa}B is catalyzed by I{kappa}B kinase complex. The phosphorylated I{kappa}B is subjected to ubiquitination and proteolytic degradation by proteasome. The degradation of I{kappa}B exposes the nuclear localization sequence in the remaining NF-{kappa}B dimers, followed by the rapid translocation of NF-{kappa}B to the nucleus, where it activates the target genes by binding to the DNA regulatory element.

Parthenolide is a sesquiterpene lactone compound and an active substance in medical herb Feverfew (Tanacetum parthenium) traditionally used in the treatment of inflammation in Mexico (Heinrich et al., 1998Go). It was shown that parthenolide blocked the NF-{kappa}B activation pathway at multiple levels such as inhibiting I{kappa}B kinase activity (Kwok et al., 2001Go) and DNA binding of NF-{kappa}B (Garcia-Pineres et al., 2001Go). In this study, we examined the effect of parthenolide in blocking the processes of UVB-mediated cutaneous alterations using cultured cell and animal models.


    Materials and Methods
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 Materials and Methods
 Results
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Reagents and Plasmids. Parthenolide, recombinant human TNF{alpha}, and IL-1 were purchased from Wako Pure Chemicals (Osaka, Japan). Antibodies to bFGF and epidermal growth factor were purchased from R&D Systems (Minneapolis, MN). The reporter plasmid expressing firefly luciferase under the control of NF-{kappa}B (pGL3-4{kappa}Bwt-Luc) was constructed by inserting four tandem copies of the {kappa}B sequence (GGGACTTTCC) from HIV-1 enhancer into pGL3-promoter vector (Promega, Madison, WI) as reported previously (Sato et al., 1998Go; Tetsuka et al., 2000Go). Construction of the mutant NF-{kappa}B reporter plasmid, pGL3-4{kappa}Bm-luc, containing mutated NF-{kappa}B binding sites, was described previously (Tetsuka et al., 2000Go). Control luciferase reporter plasmids under controls of CRB, pCRE-luc, and AP1, pAP-1-luc, were purchased from Stratagene (La Jolla, CA). The p65-expressing plasmid, pCMV-p65, was described previously (Tetsuka et al., 2000Go).

Cell Culture. The HaCaT human keratinocyte cell line (Boukamp et al., 1988Go) was generously provided by N. Fusenig (Deutsches Krebsforschungszentrum, Heidelberg, Germany). HaCaT cells were grown at 37°C in RPMI 1640 medium supplemented with 1% fetal bovine serum, 100 units/ml penicillin, and 100 µg/ml streptomycin. Human normal epidermal melanocytes (Toyobo Engineering, Osaka, Japan) were grown at 37°C in melanocyte basic medium (Toyobo Engineering) supplemented with 1% fetal bovine serum, 100 units/ml penicillin, and 100 µg/ml streptomycin. Human normal fibroblasts (KURABO, Osaka, Japan) were grown at 37°C in Dulbecco's modified Eagle's medium supplemented with 5% fetal bovine serum, 100 units/ml penicillin, and 100 µg/ml streptomycin. Human embryonic kidney 293 cells (Riken, Tsukuba, Japan) were grown at 37°C in Dulbecco's modified Eagle's medium supplemented with 10% fetal bovine serum, 1 mM glutamate, 100 units/ml penicillin, and 100 µg/ml streptomycin. For UVB irradiation, cell culture medium was changed to phosphate-buffered saline and UVB of 280- to 320-nm wavelength was irradiated at a dose of 0.5 mJ/cm2 using an FL20 S-E sunlamp (Toshiba, Tokyo, Japan). After the UVB irradiation, the fresh medium was supplied for further cultures.

Transfection and Luciferase Assay. Cells were transfected with various plasmids using Fugene-6 transfection reagent (Roche Diagnostics, Basel, Switzerland). Briefly, cells were cultured in 12-well plates, and transfections were performed with 1.5 µl of Fugene-6 transfection reagent/ml culture medium and a total of 0.5 µg of plasmid DNA as previously described (Tetsuka et al., 2000Go; Uranishi et al., 2001Go). Control plasmid pUC19 was used to equalize the amount of DNA for each transfection. Fugene-6-DNA complexes were allowed to form for 15 min at room temperature in serum-free medium before being added to the cells. After 24 h of transfection, cells were incubated for additional 24 h and then harvested. The luciferase activity was measured by the luciferase assay system (Promega). The relative light units were determined with a TD-20/20 Luminometer (Promega). Transfection efficiency was monitored by Renilla luciferase activity with pRL-TK plasmid containing TK promoter as an internal control. All luciferase activities shown in transient transfection assays were corrected by the internal control activity of Renilla luciferase by pRL-TK. The assays were performed in triplicates. The results were presented as the fold increases in luciferase activities (means ± S.D.) relative to the control in three independent transfections.

Melanocyte Growth Assay. To assess the activity promoting the growth of melanocyte in the supernatant of HaCaT cells, pCMV-p65 was transfected into HaCaT cultured in 12-well plates, cultured for 48 h, and the supernatant was obtained. Melanocytes were cultured in 24-well plates, and the supernatant of HaCaT was added to the melanocyte culture at 2:1, continued for an additional 48 h, and the numbers of melanocytes were counted using WST-1 (Roche Diagnostics). To remove bFGF from the HaCaT culture medium, the HaCaT culture supernatant was incubated with the anti-bFGF antibody premixed with 5% Sepharose A beads (Amersham Biosciences AB, Uppsala, Sweden) at 4°C for 4 h.

Quantitative Determination of bFGF and MMP-1. The commercial EIA kits were used to determine the concentrations of bFGF (Cytimmune, College Park, MD) and MMP-1 (Amersham Biosciences AB) according to the suppliers' protocol. All the measurements were performed in triplicates and repeated at least twice.

Mouse Model for the UVB-Irradiated Skin. Twenty male DBA/2 mice 6 weeks of age were subjected to this study. All mice were randomly allocated to the following four groups: UV + parthenolide treatment, UV treatment, parthenolide treatment, and control. For the groups of UV + parthenolide and UV treatments, the heads of mice were locally exposed to UVB of 280 to 320 nm wavelength at a dose of 180 mJ/cm2 using an FL20 S-E sunlamp every other day for 12 days. For the group of parthenolide treatment, 250 µg/kg parthenolide in saline was injected i.p. every day during the period of UVB irradiation. The same amount of saline was injected to UV treatment and control groups. After 12 days, ears were excised from all subjects. One of the ear specimens of each animal was stored in -80°C for the microscopic observations of melanocytes, and the other ear specimen was paraffin-embedded for the immunohistochemical analysis of MMP-1 and the determination of skin thickness by hematoxylin and eosin staining (H&E staining). The thickness of epidermis was measured using software for image analysis (Win ROOF; Mitani, Fukui, Japan). These animal experiments were performed according to the institutional regulation and were approved by the institutional review board.

Melanocyte Counting. The melanocyte count in skin tissues was determined microscopically according to the method of Hiramoto et al. (2003Go). The cartilages were manually removed from the excised mouse ear specimen, and the skin tissues were soaked in 2 N NaBr solution at 37°C for 2 h. The epidermal and basal layers were exfoliated from rest of the skin tissue by this procedure, and melanocytes were stained by immersing in 0.1 M phosphate-buffered saline (pH 7.2) containing 0.14% L-DOPA at room temperature for 3 h and counted under a microscope.

Statistical Analyses. The data were collected from at least three independent experiments. Animal experiments were performed with at least five animals per each treatment group. Quantitative data were expressed as the mean ± S.D. Statistical significance was examined by the analysis of variance and the paired Student's t test. Differences were considered statistically significant if p < 0.05. The levels of statistical significance were indicated as the following: *, p < 0.05; **, p < 0.01; and n.s., not significant.



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Fig. 1. Induction of the NF-{kappa}B-dependent gene expression in cultured human skin cells. A, diagram of reporter gene plasmids. {kappa}Bwt-luc, luciferase reporter plasmid pGL3 containing four tandem copies of the wild-type NF-{kappa}B binding site (GGGACTTTCC); {kappa}Bm-luc, containing four tandem copies of the mutant NF-{kappa}B binding site (CTCACTTTCC). B, NF-{kappa}B-dependent gene expression in HaCaT human keratinocyte cell line. C, NF-{kappa}B-dependent gene expression in human skin fibroblasts. Experiments were carried out essentially identical to those with HaCaT cells (B). Cells were transfected with {kappa}Bwt-luc or {kappa}Bm-luc reporter plasmid, stimulated with UVB (0.5 mJ/cm2), IL-1 (1.0 ng/ml), or TNF{alpha} (1.0 ng/ml). These stimuli were given 24 h after the transfection, and the cell lysates were prepared after additional 24-h incubation for determination of the luciferase activity. As a positive control (denoted as p65), pCMV-p65, expressing the p65 subunit of NF-{kappa}B, was cotransfected. As an internal control, pRL-TK, expressing Renilla luciferase under the control of TK promoter, was cotransfected. All luciferase activities were corrected by the internal control activity of Renilla luciferase. Values (-fold activation) represent the mean ± S.D. of three independent transfections. Similar results were achieved repeatedly. *, p < 0.05; **, p < 0.01; n.s., not significant.

 

    Results
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Induction of NF-{kappa}B and the Inhibitory Effects of Parthenolide in Keratinocytes and Fibroblasts. We examined the effects of UVB, IL-1, TNF{alpha}, and p65 overexpression on NF-{kappa}B dependent gene expression using transient luciferase assay. Since keratinocytes and fibroblasts are major cellular components of the skin, we used human keratinocyte cell line HaCaT as reported previously (Tebbe et al., 2001Go; Ahn et al., 2003Go) and primary human fibroblasts. Although UVB cannot penetrate the keratinocyte layer completely, approximately 10% of UVB is known to reach the upper layer of dermis consisting of fibroblasts (Fujisawa et al., 1997Go). These cells were transfected with luciferase reporter plasmids containing either wild-type {kappa}B sites or mutated {kappa}B sites, and extents of gene expression were compared in the presence or the absence of these stimuli (Fig. 1).

In HaCaT cells, UVB, IL-1, TNF{alpha}, and p65 stimulated gene expression from the reporter plasmid containing NF-{kappa}B binding sites by 2.5-, 2.4-, 5.8-, and 6.9-fold, respectively, whereas no significant stimulation was observed when the reporter plasmid containing mutant NF-{kappa}B sites was used. Even higher NF-{kappa}B-dependent activation was observed in primary fibroblasts. UVB, IL-1, TNF{alpha}, and p65 stimulated the luciferase gene expression by 3.3-, 6.7-, 8.9-, and 19.2-fold, respectively. Similar observations were made in 293 cells, a fibroblast cell line derived from human kidney (data not shown). We then examined the effect of parthenolide on the TNF{alpha}-mediated NF-{kappa}B-dependent gene expression. As shown in Fig. 2, when parthenolide was added to the 293-cell culture, the NF-{kappa}B-mediated gene expression was inhibited in a dose-dependent manner for the concentration of parthenolide. In contrast, no such effect of parthenolide was observed on AP-1- or CREB-dependent gene expression. These effects were observed under noncytotoxic concentrations of parthenolide (data not shown).



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Fig. 2. Inhibition of NF-{kappa}B-dependent gene expression by parthenolide. A, effects of parthenolide on NF-{kappa}B-dependent gene expression. Experiments were similarly performed as in Fig. 1 except that cells were pretreated with parthenolide at 2.5, 5, or 10 µM of final concentration 2 h prior to the TNF{alpha} (1.0 ng/ml) treatment. B and C, effects of parthenolide on gene expression dependent on AP-1 (B) and CREB (C). Parthenolide, at final concentrations of 2.5, 5, or 10 µM, was added 2 h prior to the TNF{alpha} or forskolin treatment. Values represent the luciferase activity means ± S.D. of three independent transfections. **, p < 0.01; n.s., not significant.

 
Induction of bFGF and MMP-1 by NF-{kappa}B and the Effects of Parthenolide. The UV-induced cutaneous alterations are known to be mediated by bFGF and MMP-1 (Pittelkow and Shipley, 1989Go; Chung, 2003Go). Since it was previously shown that production of bFGF and MMP-1 was induced by UVB (Sabourin et al., 1993Go; Brenneisen et al., 2002Go) and that UVB irradiation induced production of IL-1 and TNF{alpha} in keratinocytes and fibroblasts (Corsini et al., 1997Go; Fujisawa et al., 1997Go), we examined if p65 overexpression, mimicking NF-{kappa}B activation, induced production of bFGF and MMP-1. As shown in Fig. 3A, when p65 was overexpressed in keratinocytes and fibroblasts, bFGF production into the culture supernatant was significantly augmented although the transfection efficiency was approximately 3.8 and 9.2% for HaCaT cells and fibroblasts, respectively. Similar effects were observed in the MMP-1 production (Fig. 3B). The amounts of bFGF and MMP-1 production were significantly reduced, almost to the basal level, by the treatment with parthenolide. When mice were treated with parthenolide i.p., significant reduction of the MMP production upon UVB irradiation was observed (data not shown), consistent with the results with cultured cells.



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Fig. 3. Effect of NF-{kappa}B on production of bFGF and MMP-1 from cultured skin cells and its inhibition by parthenolide. A, effect of NF-{kappa}B on production of bFGF. HaCaT or skin fibroblasts were transiently transfected with pCMV-p65, and the culture supernatants were collected after 72 h of transfection for determination of bFGF. Parthenolide (10 µM) was added to each cell culture 24 h after the transfection. The amount of bFGF produced from 104 cells was indicated. B, effect of NF-{kappa}B on production of MMP-1. HaCaT or skin fibroblasts were transiently transfected with pCMV-p65, incubated for 72 h, and the MMP-1 production in the culture supernatant per 104 cells was determined. The inhibitory effect of parthenolide was similarly evaluated. Experiments were performed in triplicate, and the values represent the mean ± S.D. of three independent experiments. Similar results were achieved repeatedly. *, p < 0.05; **, p < 0.01.

 

Effects of Parthenolide on Epidermal Hyperproliferation and Melanocyte Growth. It is well known that the UV-induced epidermal hyperplasia, consisting of the hyperproliferative keratinocytes and melanocytes (Brenneisen et al., 2002Go; Chung, 2003Go; Hirobe et al., 2003Go) is considered to be due to the action of bFGF induced by UVB (Pittelkow and Shipley, 1989Go; Bielenberg et al., 1998Go). In Fig. 4, effects of parthenolide on the UVB-induced epidermal hyperproliferation were shown. UVB (180 mJ/cm2) was irradiated at the head of mice. Although UVB induced epidermal hyperproliferation by 2.9-fold compared with the control untreated skin, treatment with parthenolide significantly reduced the epidermal hyperproliferation to 1.6-fold.



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Fig. 4. Epidermal hyperproliferation by UV and inhibition by parthenolide. A, epidermal hyperproliferation by UVB. Parthenolide (250 µg/kg) or physiological saline as control was administered to DBA/2 mice (n = 10 for each group) by repeated i.p. injections every day for 12 days. Half of the mice in each group were exposed to UVB irradiation at 180 mJ/cm2 every other day. Ear samples were prepared from the anesthetized mice, paraffin-embedded, and cut with a sliding microtome to 5-µm thickness. Tissue sections were subjected to histological examination (H&E staining). Representative pictures are shown. Arrowheads indicate the width of epidermis. B, measurement of the epidermal hyperproliferation induced by UVB and effect of parthenolide. All specimens (n = 5 per group) were examined microscopically for the measurement of epidermal thickness. Data shown are the mean ± S.D. (n = 5) of the average epidermal thickness measured using software for image analysis (Win ROOF). -Fold increase in the epidermal thickness compared with the control is indicated. **, p < 0.01; scale bar = 20 µm.

 
We then examined the effects of parthenolide on the melanocyte growth (Fig. 5). The epidermal and basal layers were exfoliated from the skin tissue and melanocytes were stained by L-DOPA. As demonstrated in Fig. 5B, although UVB induced melanocyte proliferation by 3.1-fold in the number of melanocytes compared with the control untreated skin, it was significantly reduced by the treatment with parthenolide to 2.1-fold compared with the control.



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Fig. 5. Induction of melanocyte proliferation by UVB and its inhibition by parthenolide. A, L-DOPA staining of skin melanocytes. DBA/2 mice were treated with parthenolide (250 µg/kg) and exposed to UVB (180 mJ/cm2) as in Fig. 4. Parthenolide or physiological saline was repeatedly administered to DBA/2 mice by i.p. injection once a day for 12 days. Half of the mice in each group were exposed to UVB irradiation of 180 mJ/cm2 every other day. To stain melanocyte, the ears obtained from each mouse were soaked in 2 N NaBr solution for exfoliating epidermis and immersed in 0.14% L-DOPA solution for 3 h at room temperature. B, melanocyte counting. All specimens (n = 5 per group) were examined microscopically for counting the DOPA-positive melanocytes in the epidermis. Data shown are the mean ± S.D. of the number of melanocytes per millimeter squared. -Fold increase in the melanocyte numbers compared with the control is indicated. **, p < 0.01; scale bar = 80 µm.

 

Promotion of the Melanocyte Growth by Keratinocytes and Involvement of bFGF. In Fig. 6, we examined if bFGF stimulated the growth of melanocyte and if keratinocytes, upon NF-{kappa}B activation, produced bFGF. After 48 h of the bFGF treatment, a dose-dependent stimulation of melanocyte growth was observed (Fig. 6A). Since keratinocytes are known to produce bFGF (Bielenberg et al., 1998Go), which acts as a growth factor for melanocytes (Krasagakis et al., 1995Go), and NF-{kappa}B has been shown to activate production of bFGF (Wakisaka et al., 2002Go), we examined the effect of the culture supernatant of keratinocytes in which NF-{kappa}B was activated on the melanocyte growth. In Fig. 6B, p65 was overexpressed in HaCaT keratinocytes (HaCaT-p65), and the culture supernatant was examined for the growth-promoting effect on melanocytes. As shown here, a significant increase in the melanocyte growth was observed after incubation with the culture supernatant of HaCaT-p65 (Fig. 6B). In fact, bFGF was detected in the HaCaT-p65 culture supernatant (14.8 ± 1.53 ng/ml), whereas the level of bFGF in parental HaCaT cells was less than 6 ng/ml. When the HaCaT-p65 supernatant was preincubated with the neutralizing antibody to bFGF, the melanocyte growth-promoting effect was completely abolished (Fig. 6B), whereas the anti-EGF antibody did not show such effect. From these observations, it was suggested that keratinocytes were responsible for the melanocyte proliferation and that this effect was mediated by bFGF.



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Fig. 6. Involvement of bFGF in the melanocyte proliferation and its production from keratinocytes. A, induction of melanocyte proliferation by bFGF. Primary human melanocytes were cultured in melanocyte basic medium, and the effects of bFGF of 1, 10, and 100 ng/ml were examined. The numbers of melanocytes were determined by WST method after 48 h of culture. B, involvement of bFGF in the keratinocyte-mediated melanocyte proliferation. HaCaT cells were transfected with pCMV-p65 as in Fig. 3, and the culture supernatant was collected after 48 h of transfection. As a control, pUC19 plasmid was transfected into HaCaT. The anti-bFGF or anti-EGF antibody was incubated with the supernatants of these transfected HaCaT cells, and bFGF or EGF was removed. These supernatant samples were then added to the melanocyte and incubated for an additional 72 h. The numbers of melanocyte were counted by WST method. Data shown are the mean ± S.D. (n = 5) of the number of melanocytes. *, p < 0.05; **, p < 0.01.

 


    Discussion
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 Abstract
 Materials and Methods
 Results
 Discussion
 References
 
UV is one of the most harmful environmental factors for skin (Kligman, 1989Go; Ulrich et al., 2004Go; Wulf et al., 2004Go) and is responsible for the skin aging. Most characteristic changes of the skin induced by UVB have been ascribed to the production of proinflammatory cytokines, including IL-1 and TNF{alpha} (Wlaschek et al., 1994Go; Fisher et al., 1996Go; Corsini et al., 1997Go; Yarosh et al., 2000Go) and effector molecules, such as MMP-1 and bFGF (Wlaschek et al., 1994Go; Barchowsky et al., 2000Go). It is well established that expressions of IL-1, TNF{alpha}, MMP-1, and bFGF are controlled by NF-{kappa}B, which is activated by UV irradiation (Barchowsky et al., 2000Go; Wakisaka et al., 2002Go). NF-{kappa}B is a crucial factor for the immunoinflammatory responses and is also implicated in various skin diseases including allergic dermatitis, psoriasis vulgaris, and skin cancer (Bell et al., 2003Go). Hence, although NF-{kappa}B is involved in maintaining the skin homeostasis (Pasparakis et al., 2002Go; Takao et al., 2003Go), excessive activation is pathogenic. Thus, inhibition of NF-{kappa}B is considered to prevent the pathogenetic changes induced by UVB. In this study, we have examined the causal association of NF-{kappa}B with the UVB-induced changes in the skin and the efficacy of one such inhibitor, parthenolide.

Although parthenolide is known to have inhibitory action on NF-{kappa}B (Heinrich et al., 1998Go; Hehner et al., 1999Go), such as inhibitions of NF-{kappa}B DNA binding (Garcia-Pineres et al., 2001Go) and I{kappa}B kinase (Hehner et al., 1999Go), its specificity has not been clearly demonstrated. We found that parthenolide specifically inhibited the NF-{kappa}B-dependent gene expression and did not affect the actions of other transcription factors such as AP-1 and CREB. Although Won et al. (2004Go) recently reported the inhibitory action of parthenolide on AP-1 and claimed its chemopreventive activity against UVB-induced skin cancer, we did not observe such inhibitory effect on AP1, which might be due to the differences of cell lineages used or the experimental procedures applied.



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Fig. 7. Diagrammatic representation of the action of NF-{kappa}B in the process of UVB-mediated cutaneous alterations (photoaging). Environmental stimuli, such as UV irradiation and inflammatory signaling, induce the NF-{kappa}B activation that leads to the production of MMP-1 and bFGF in epidermal keratinocytes. The up-regulation of bFGF promotes proliferation of keratinocytes and melanocytes as a protection mechanism to these environmental insults. In dermis, skin fibroblasts are stimulated by UV and proinflammatory cytokines, such as IL-1 and TNF{alpha}, produced by keratinocytes, and then NF-{kappa}B is activated, leading to the MMP-1 production. Thus, NF-{kappa}B inhibitors are considered to be effective in preventing the UVB-mediated cutaneous alterations and eventually the skin photoaging process.

 
Thus, the effect of parthenolide seems to be specific. Since parthenolide was effective in blocking the induction of MMP-1 and bFGF even in cells overexpressing p65, bypassing the activation signaling of NF-{kappa}B, it is possible that parthenolide can inhibit NF-{kappa}B DNA binding or transactivation process following the DNA binding such as the recruitment of basal transcription factors or coactivators (Uranishi et al., 2001Go; Jiang et al., 2003Go). However, further analysis of parthenolide action is needed to clarify its mode of action.

The possible involvement of NF-{kappa}B in the UV-mediated cutaneous alteration, or skin photoaging, through induction of MMP-1 and bFGF has been implicated (Bond et al., 1999Go; Abeyama et al., 2000Go; Barchowsky et al., 2000Go; Wakisaka et al., 2002Go). We have confirmed these findings in this study using cultured cells and short-term irradiation experiments using mice. In addition, we found that NF-{kappa}B activation is involved in the melanocyte proliferation, which was consistent with the previous observations by others such as the involvement of bFGF in melanocyte proliferation (Pittelkow and Shipley, 1989Go). Interestingly, impaired bFGF production is reported in the vitiliginous patient skin where melanin deposition in the skin is partially affected (Moretti et al., 2002Go). In addition, kojic acid and ascorbic acid, identified as active whitening ingredients for the skin, have been shown to inhibit the NF-{kappa}B-mediated gene expression (Ahn et al., 2003Go).

These findings support an idea that NF-{kappa}B is involved in various steps in the UVB-mediated skin change both directly and indirectly. Thus, inhibition of NF-{kappa}B activation should be effective in preventing the process of UVB-mediated cutaneous alterations and eventually photoaging (schematically demonstrated in Fig. 7). Although we did not observe any side effect in experimental parthenolide therapy of mice as long as we observed (12 days), longer treatment might cause unexpected side effects such as immunosuppression and deteriorated host defense considering NF-{kappa}B being a major determinant for immunological and inflammatory responses. Further studies are needed regarding the chronic effects and the possible toxicity of parthenolide.


    Acknowledgements
 
We thank Dr. Akimichi Morita (Department of Dermatology, Nagoya City University) for helpful discussion and comments.


    Footnotes
 
This work was supported in part by the Ministry of Health, Labor and Welfare (Grant-in-Aid H16-Immunology-001) and by the Ministry of Education, Culture, Sports, Science and Technology of Japan (Grant-in-Aid 16022254).

Article, publication date, and citation information can be found at http://jpet.aspetjournals.org.

doi:10.1124/jpet.105.088674.

ABBREVIATIONS: IL-1, interleukin-1; TNF{alpha}, tumor necrosis factor {alpha}; MMP-1, matrix metalloprotease-1; bFGF, basic fibroblast growth factor; NF-{kappa}B, nuclear factor {kappa}B; I{kappa}B, inhibitor {kappa}B.

Address correspondence to: Dr. Takashi Okamoto, Department of Molecular and Cellular Biology, Nagoya City University Graduate School of Medical Sciences, 1 Kawasumi, Mizuho-cho, Mizuho-ku, Nagoya, Aichi 467-8601, Japan. E-mail: tokamoto{at}med.nagoya-cu.ac.jp


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 Discussion
 References
 

Abeyama K, Eng W, Jester JV, Vink AA, Edelbaum D, Cockerell CJ, Bergstresser PR, and Takashima A (2000) A role for NF-{kappa}B-dependent gene transactivation in sunburn. J Clin Investig 105: 1751-1759.[Medline]

Ahn KS, Moon KY, Lee J, and Kim YS (2003) Downregulation of NF-{kappa}B activation in human keratinocytes by melanogenic inhibitors. J Dermatol Sci 31: 193-201.[CrossRef][Medline]

Barchowsky A, Frleta D, and Vincenti MP (2000) Integration of the NF-{kappa}B and mitogen-activated protein kinase/AP-1 pathway at the collagenase-1 promotor: divergence of IL-1 and TNF-dependent signal transduction in rabbit primary synovial fibroblasts. Cytokine 12: 1469-1479.[CrossRef][Medline]

Bell S, Degitz K, Quirling M, Jilg N, Page S, and Brand K (2003) Involvement of NF-{kappa}B signalling in skin physiology and disease. Cell Signal 15: 1-7.[CrossRef][Medline]

Bielenberg DR, Bucana CD, Sanchez R, Donawho CK, Kripke ML, and Fidler IJ (1998) Molecular regulation of UVB-induced cutaneous angiogenesis. J Investig Dermatol 111: 864-872.[CrossRef][Medline]

Bond M, Baker AH, and Newby AC (1999) Nuclear factor {kappa}B activity is essential for matrix metalloproteinase-1 and -3 upregulation in rabbit dermal fibroblasts. Biochem Biophys Res Commun 264: 561-567.[CrossRef][Medline]

Boukamp P, Petrussevska RT, Breitkreutz D, Hornung J, Markham A, and Fusenig NE (1988) Normal keratinization in a spontaneously immortalized aneuploid human keratinocyte cell line. J Cell Biol 106: 761-771.[Abstract/Free Full Text]

Brenneisen P, Sies H, and Scharffetter-Kochanek K (2002) Ultraviolet-B irradiation and matrix methalloproteinases: from induction via signaling to initial events. Ann NY Acad Sci 973: 31-43.[Abstract/Free Full Text]

Chung JH (2003) Photoaging in Asians. Photodermatol Photoimmunol Photomed 19: 109-121.[CrossRef][Medline]

Corsini E, Sangha N, and Feldman SR (1997) Epidermal stratification reduces the effects of UVB (but not UVA) on keratinocyte cytokine production and cytoxicity. Photodermatol Photoimmunol Photomed 13: 147-152.[Medline]

Fisher GJ, Datta SC, Talwar HS, Wang ZQ, Varani J, Kang S, and Voorhees JJ (1996) Molecular basis of sun-induced premature skin ageing and retinoid antagonism. Nature (Lond) 379: 335-339.[CrossRef][Medline]

Fujisawa H, Wang B, Kondo S, Shivji GM, and Sauder DN (1997) Costimulation with ultraviolet B and interleukin-1 alpha dramatically increase tumor necrosis factor-alpha production in human dermal fibroblasts. J Interferon Cytokine Res 17: 307-313.[Medline]

Garcia-Pineres AJ, Castro V, Mora G, Schmidt TJ, Strunck E, Pahl HL, and Merfort I (2001) Cysteine 38 in p65/NF-{kappa}B plays a crucial role in DNA binding inhibition by sesquiterpene lactone. J Biol Chem 276: 39713-39720.[Abstract/Free Full Text]

Hayden MS and Ghosh S (2004) Signaling to NF-{kappa}B. Genes Dev 18: 2195-2224.[Abstract/Free Full Text]

Hehner SP, Hofmann TG, Droge W, and Schmitz ML (1999) The antiinflammatory sesquiterpene lactone parthenolide inhibits NF-{kappa}B by targeting the I {kappa}B kinase complex. J Immunol 163: 5617-5623.[Abstract/Free Full Text]

Heinrich M, Robles M, West JE, Ortiz de Montellano BR, and Rodriguez E (1998) Ethnopharmacology of Mexican asteraceae (Compositae). Annu Rev Pharmacol Toxicol 38: 539.[CrossRef][Medline]

Hiramoto K, Yanagihara N, Sato EF, and Inoue M (2003) Ultraviolet B irradiation of the eye activates a nitric oxide-dependent hypothalamopituitary proopiomekanocortin pathway and modulates functions of alpha melanocyte-stimulating hormone-responsive cells. J Investig Dermatol 120: 123-127.[CrossRef][Medline]

Hirobe T, Furuya R, Akiu S, Ifuku O, and Fukuda M (2003) Keratinocytes control the proliferation and differentiation of cultured epidermal melanocytes from ultraviolet radiation B-induced pigmented spots in the dorsal skin of hairless mice. Pigment Cell Res 15: 391-399.[CrossRef]

Jiang X, Takahashi N, Matsui N, Tetsuka T, and Okamoto T (2003) The NF-kB activation in lymphotoxin beta receptor signaling depends on the phosphorylation of p65at serine 536. J Biol Chem 278: 919-926.[Abstract/Free Full Text]

Kligman LH (1989) Photoaging: manifestations, prevention and treatment. Clin Geriatr Med 5: 235-251.[Medline]

Krasagakis K, Garbe C, Zouboulis CC, and Orfanos CE (1995) Growth control of melanoma cells and melanocytes by cytokines. Recent Results Cancer Res 139: 169-182.[Medline]

Kwok BH, Koh B, Ndubuisi MI, Elofsson M, and Crews CM (2001) The antiinflammatory natural product parthenolide from the medical herb Feverfew directly binds to and inhibits I{kappa}B kinase. Chem Biol 8: 759-766.[CrossRef][Medline]

Moretti S, Spallanzani A, Amano L, Hautmann G, Gallerani I, Fabiani M, and Fabbri P (2002) New insights into the pathogenesis of vitiligo: imbalance of epidermal cytokines at sites of lesions. Pigment Cell Res 15: 87-92.[CrossRef][Medline]

Okamoto T, Sakurada S, Yang JP, and Merin JP (1997) Regulation of NF-{kappa}B and disease control: identification of a novel serine kinase and thioredoxin as effectors for signal transduction pathway for NF-{kappa}B activation. Curr Top Cell Regul 35: 149-161.[Medline]

Pasparakis M, Courtois G, Hafner M, Schmidt-Supprian M, Nenci A, Toksoy A, Krampert M, Goebeler M, Gillitzer R, Israel A, et al. (2002) TNF-mediated inflammatory skin disease in mice with epidermis-specific deletion of IKK2. Nature (Lond) 417: 861-866.[CrossRef][Medline]

Pittelkow MR and Shipley GD (1989) Serum-free culture of normal human melanocytes: growth kinetics and growth factor requirements. J Cell Physiol 140: 565-576.[CrossRef][Medline]

Sabourin CL, Kusewitt DF, Applegate LA, Budge CL, and Ley RD (1993) Expression of fibroblast growth factors in ultraviolet radiation-induced corneal tumors and corneal tumor cell lines from Monodelphis domestica. Mol Carcinog 7: 197-205.[Medline]

Saliou C, Kitazawa M, McLaughlin L, Yang JP, Lodge JK, Tetsuka T, Iwasaki K, Cillard J, Okamoto T, and Packer L (1999) Antioxidants modulate acute solar ultraviolet radiation-induced NF-kappaB activation in a human keratinocyte cell line. Free Radic Biol 26: 174-183.

Sato T, Asamitsu K, Yang JP, Takahashi N, Tetsuka T, Yoneyama A, Kanagawa A, and Okamoto T (1998) Inhibition of human immunodeficiency virus type 1 replication by a bioavailable serine/threonine kinase inhibitor, fasudil hydrochloride. AIDS Res Hum Retrovir 14: 293-298.[Medline]

Sun HB, Malacinski GM, and Yokota H (2002) Promoter competition assay for analyzing gene regulation in joint tissue engineering. Front Biosci 7: 169-174.

Takao J, Yudate T, Das A, Shikano S, Bonkobara M, Ariizumi K, and Cruz PD (2003) Expression of NF-{kappa}B in epidermis and the relationship between NF-{kappa}B activation and inhibition of keratinocyte growth. Br J Dermatol 148: 680-688.[CrossRef][Medline]

Tebbe B, Schwarz C, Ruderisch HS, Treudler R, and Orfanos CE (2001) L-ascorbic acid increase NF{kappa}B binding activity in UVA-irradiated HaCaT keratinocyte. J Investig Dermatol 117: 154-156.[CrossRef][Medline]

Tetsuka T, Uranishi H, Imai H, Ono T, Sonta S, Takahashi N, Asamitsu K, and Okamoto T (2000) Inhibition of nuclear factor-{kappa}B-mediated transcription by association with the amino-terminal enhancer of split, a Groucho-related protein lacking WD40 repeats. J Biol Chem 275: 4383-4390.[Abstract/Free Full Text]

Ulrich C, Schmook T, Sachse MM, Sterry W, and Stockfleth E (2004) Comparative epidemiology and pathogenic factors for non-melanoma skin cancer in organ transplant patients. Dermatol Surg 30: 622-627.[CrossRef][Medline]

Uranishi H, Tetsuka T, Yamashita M, Asamitsu K, Shimizu M, Itoh M, and Okamoto T (2001) Involvement of the pro-oncoprotein TLS (translocated in liposarcoma) in nuclear factor-{kappa}B p65-mediated transcription as a coactivator. J Biol Chem 276: 13395-13401.[Abstract/Free Full Text]

Wakisaka N, Murono S, Yoshizaki T, Furukawa M, and Pagano JS (2002) Epstein-Barr virus latent membrane protein 1 induces and causes release of fibroblast growth factor-2. Cancer Res 62: 6337-6344.[Abstract/Free Full Text]

Wlaschek M, Heinen G, Poswig A, Schwarz A, Krieg T, and Scharffetter-Kochanek K (1994) UVA-induced autocrine stimulation of fibroblast-derived collagenase/MMP-1 by interrelated loops of interleukin-1 and interleukin-6. Photochem Photobiol 59: 550-556.[Medline]

Won YK, Ong CN, Shi X, and Shen HM (2004) Chemopreventive activity of parthenolide against UVB-induced skin cancer and its mechanisms. Carcinogenesis 25: 1449-1458.[Abstract/Free Full Text]

Wulf HC, Sandby-Moller J, Kobayashi T, and Gniadecki R (2004) Skin aging and natural photoprotection. Micron 35: 185-191.

Yarosh D, Both D, Kibitel J, Anderson C, Elmets C, Brash D, and Brown D (2000) Regulation of TNF{alpha} production and release in human and mouse keratinocytes and mouse skin after UV-B irradiation. Photodermatol Photoimmunol Photomed 16: 263-270.[CrossRef][Medline]


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