Modulation of skin collagen metabolism in aged and photoaged human skin in vivo.

To the best of our knowledge, no study has been conducted to date to directly compare the collagen metabolism of photoaged and naturally aged human skin. In this study, we compared collagen synthesis, matrix metalloproteinase-1 levels, and gelatinase activity of sun-exposed and sun-protected skin of both young and old subjects. Using northern blot analysis, immunohistochemical stain, and Western blot analysis, we demonstrated that the levels of procollagen type I mRNA and protein in photoaged and naturally aged human skin in vivo are significantly lower than those of young skin. Furthermore, we demonstrated, by northern blot analysis, that the procollagen alpha1(I) mRNA expression of photoaged skin is much greater than that of sun-protected skin in the same individual. In situ hybridization and immunohistochemical stain were used to show that the expression of type I procollagen mRNA and protein in the fibroblasts of photoaged skin is greater than for naturally aged skin. In addition, it was found, by Western blot analysis using protein extracted from the dermal tissues, that the level of procollagen type I protein in photoaged skin is lower than that of naturally aged skin. The level of matrix metalloproteinase-1 protein and the activity of matrix metalloproteinase-2 were higher in the dermis of photoaged skin than in naturally aged skin. Our results suggest that the natural aging process decreases collagen synthesis and increases the expression of matrix metalloproteinases, whereas photoaging results in an increase of collagen synthesis and greater matrix metalloproteinase expression in human skin in vivo. Thus, the balance between collagen synthesis and degradation leading to collagen deficiency is different in photoaged and naturally aged skin.     

Ultraviolet irradiation-induced inhibition of histone deacetylase 4 increases the expression of matrix metalloproteinase-1 but decreases that of type I procollagen via activating JNK in human dermal fibroblasts

BackgroundUltraviolet (UV) irradiation is the main contributing factor for skin aging. UV irradiation induces epigenetic changes in skin. It increases the activity of histone acetylases (HATs) but decreases that of histone deacetylases (HDACs).ObjectiveWe aimed to investigate alterations in all classes of HDACs and sirtuins (SIRTs) in response to UV irradiation, and determine the HDACs regulating the expressions of matrix metalloproteinase 1 (MMP-1) and type I procollagen.MethodsPrimary human dermal fibroblasts were UV irradiated. HDAC4 was knocked-down or overexpressed to investigate its effect on the expression of MMP-1 and type I procollagen. The mRNA and protein levels were analyzed by quantitative real-time polymerase chain reaction and western blotting.ResultsAmong 11 HDACs and 7 SIRTs, we found that the expression of HDAC4, HDAC5, HDAC6, HDAC7, HDAC8, HDAC11, SIRT2, and SIRT3 were significantly and consistently reduced by UV at both mRNA and protein levels. Among these, the reduction of HDAC4 was responsible for the basal and UV-induced increase in the expression of MMP-1 and decrease in that of type I procollagen. Furthermore, the reduced HDAC4 could activate c-Jun N-terminal kinase (JNK), resulting in an increase in MMP-1 and decrease in type I procollagen.ConclusionsUV treatment decreases the expression of HDACs and SIRTs in dermal fibroblasts; in particular, the UV-induced reduction in the expression of HDAC4 might play an important role in regulating the expression of MMP-1 and type I procollagen.     

Effects of dehydroepiandrosterone on collagen and collagenase gene expression by skin fibroblasts in culture

Dehydroepiandrosterone (DHEA) and its sulfate (DHEA-S) are the most abundant steroids in humans whose low levels are related to aging, greater incidence of various cancers, immune dysfunction, atherosclerosis, and osteoporosis. It has been shown that collagen and collagenase gene expression decreases in fibroblasts taken from more aged donors. In this paper, to investigate the relationship between DHEA and skin aging, we examined the effects of DHEA on the regulation of collagen, collegians and stromelysin-1 genes in cultured human skin fibroblasts. In collagen assay, DHEA slightly increased collagen production in a dose-related fashion, its maximal effect occurred at 10(-5) M DHEA (P>0.05). In the presence of DHEA, steady-state levels of alpha1 (I) procollagen mRNA increased to 1. 6-fold of the non-treated group, while those of fibronectin were not. Interestingly, DHEA differently regulated collagenase and stromelysin-1 gene expression. The steady-state levels of collagenase mRNA decreased in response to DHEA by 40%, whereas those of stromelysin-1 mRNA increased up to 2.4-fold, compared to controls. Similar results were obtained for chloramphenicol acetyltransferase assay (CAT); maximal promoter activation of stromelysin-1 gene occurred at 10(-6) M DHEA, 4.5-fold higher than control. CAT assay revealed that treatment with 10(-5) M DHEA resulted in a strong ( approximately 70%) inhibition of the collagenase promoter activity. In our experiments, the effects of DHEA on these gene expressions were higher at pharmacologic concentration (>/=10(-5) M) than those at physiologic concentration (10(-8)-10(-6) M). This study suggests that the level of DHEA may be related to the process of skin aging through the regulation of production and degradation in extracellular matrix.     

基质金属蛋白酶表达在皮肤光老化皱纹形成中的作用

目的 探讨皮肤光老化皱纹形成与真皮成纤维细胞基质金属蛋白酶(MMP)-1,MMP-3mRNA及其组织抑制剂(TIMP)-1表达的关系。方法 采用原位杂交和免疫组化的方法检测紫外线光化学疗法(PUVA)治疗期间及治疗后不同时间银屑病患者背部非皮损区真皮成纤维细胞MMP-1,MMP-3mRNA及TIMP-1蛋白的表达并定量分析。结果 在PUVA治疗期间、治疗后1~6个月及治疗后6个月以上的银屑病患者背部非皮损区真皮成纤维细胞均持续表达MMP-1、MMP-3mRNA,而TIMP-1蛋白仅在治疗期间一过性轻度表达。结论 PUVA治疗引起的皮肤光老化皱纹形成可能与真皮成纤维细胞基质金属蛋白酶及其组织抑制剂表达失衡密切相关。     

Topical application of 17beta-estradiol increases extracellular matrix protein synthesis by stimulating tgf-Beta signaling in aged human skin in vivo

To investigate the effects of topically applied 17beta-estradiol on the expression of extracellular matrix proteins in aged human skin, 17beta-estradiol (0.01%) and its vehicle (70% propylene glycol, 30% ethanol) were applied to aged (68-82 y, eight females and five males) human buttock skin under occlusion for 2 wk (three times per week). Topical 17beta-estradiol was found to increase the expression of type 1 procollagen mRNA and protein significantly in human aged skin in vivo. In addition, metalloproteinase (MMP-1 protein levels were reduced by topical 17beta-estradiol. The expressions of TGF-beta1, TGF-beta type II receptor, and Sma and Mad related (Smad)3 were increased by topical 17 beta-estradiol in aged human skin, and TGF-beta1 neutralizing antibody inhibited 17beta-estradiol-induced procollagen synthesis in cultured fibroblasts. We also found that the expressions of tropoelastin and fibrillin-1 mRNA and protein, and elastic fibers in aged skin were also increased by topical 17beta-estradiol. Topical 17beta-estradiol also increased keratinocyte proliferation and the epidermal thickness in aged human skin. We also observed the same effects of topical 17beta-estradiol in young skin. In conclusion, our results suggest that topical 17beta-estradiol treatment may improve the cutaneous function of aged human skin by improving the connective tissue and increasing epidermal thickness.     

Exogenous nitric oxide enhances the synthesis of type I collagen and heat shock protein 47 by normal human dermal fibroblasts

BACKGROUND: It is well established that the alterations of dermal matrix contributes to skin aging characterized by wrinkles. On the other hand, physiological NO is useful to maintain skin homeostasis such as a vasodilatation. However, a role of NO on production of dermal matrix has been clarified. OBJECTIVE: In this study, we have attempted to analyze the role of NO on type I collagen synthesis of normal human dermal fibroblasts including expression of procollagen alphaI S(1) mRNA/protein and heat shock protein 47 (HSP47). METHODS: The effects of NO which was generated by two types of NO donors, sodium nitroprusside (SNP) and S-nitroso-N-acetylpenicillamine (SNAP), on type I collagen and HSP47 and their related mRNA expression were examined with ELISA and RT-PCR. RESULTS: NO was significantly accelerated the production of type I collagen by fibroblasts corresponding with up-regulation of procollagen alphaI (1) mRNA. Furthermore, NO increased both levels of HSP47 protein and mRNA in fibroblasts in a dose-dependent manner. CONCLUSIONS: These results suggest that NO has dual effects on collagen synthesis by fibroblasts as follows; one is the direct stimulation of collagen synthesis due to the up-regulation of procollagen alphaI(1) mRNA, and the other is an indirect effect through the increase of HSP47 mRNA expression. This is the first report that exogenous NO stimulates HSP47 production by dermal fibroblasts.     

Gene expression of types I and III collagen, decorin, matrix metalloproteinases and tissue inhibitors of metalloproteinases in skin fibroblasts from patients with systemic sclerosis

Cultured fibroblasts from patients with systemic sclerosis (SSc) and normal individuals were examined for gene expression of types I and III collagen, decorin, matrix metalloproteinases (MMP) MMP-1, MMP-2, and MMP-3, tissue inhibitors of metalloproteinases (TIMP) TIMP-1 and TIMP-2, urokinase- and tissue-type plasminogen activators (u-PA and t-PA). Fibroblasts from patients with early stage SSC (less than 1 year duration of disease) exhibited higher levels of types I and III procollagen, decorin, MMP-1, MMP-3, TIMP-1, and PAs than those from normal individuals. The gene expression of procollagen α1(I) and TIMP-1 mRNAs were increased, but those of decorin, MMP-1, MMP-2, and MMP-3 were decreased, in fibroblasts from SSc patients with mid-stage SSc (2 to 4 years duration) as compared with those from normal individuals. In contrast, no significant difference in gene expression was found between fibroblasts from normal individuals and from patients with late-stage SSc (more than 6 years duration). These results suggest that gene expression of collagen, decorin, and degrading factors is dynamically modulated during fibrillogenesis. The responses of procollagen α1(I) mRNA to IL-1 and TGF-β were lower in fibroblasts from SSc patients with early and mid-stage disease, but not in those from patients with-late stage disease, than in control fibroblasts, which indicates that these cytokines may be involved in the earlier phases of fibrosis in SSc. Received: 30 August 1996     

The effects of ultraviolet A and reactive oxygen species on the mRNA expression of 72-kDa type IV collagenase and its tissue inhibitor in cultured human dermal fibroblasts

The effects of ultraviolet A (UVA) radiation and reactive oxygen species (ROS), generated with a xanthine and xanthine oxidase (XOD) system, on collagen enzymatic degradation involving the matrix metalloproteinase (MMP) and its tissue inhibitor of metalloproteinase (TIMP) were investigated using cultured human dermal fibroblasts. Total RNA was isolated and subjected to Northern blot analysis using cDNA clones for human interstitial collagenase (MMP-1), 72-kDa type IV collagenase (MMP-2) and TIMP-2. UVA irradiation resulted in an increase in MMP-1 mRNA up to 2.3-fold, but did not stimulate MMP-2 or TIMP-2 mRNA expression. In contrast, ROS induced by the xanthine and XOD system resulted in a dose-related increase in the level of MMP-2 mRNA up to 2.1-fold and a decrease in the level of TIMP-2 mRNA by 49% in the same fibroblasts. Catalase, used as scavenger, essentially prevented the ROS-induced alterations in MMP-2 and TIMP-2 mRNA levels. These results suggest that ROS produced in the dermis may contribute to biological changes in the connective tissue matrix observed in photoaging skin by accelerating the MMP-2-related matrix degradation system. Received: 6 September 1994     

The effects of ultraviolet A and reactive oxygen species on the mRNA expression of 72-kDa type IV collagenase and its tissue inhibitor in cultured human dermal fibroblasts

The effects of ultraviolet A (UVA) radiation and reactive oxygen species (ROS), generated with a xanthine and xanthine oxidase (XOD) system, on collagen enzymatic degradation involving the matrix metalloproteinase (MMP) and its tissue inhibitor of metalloproteinase (TIMP) were investigated using cultured human dermal fibroblasts. Total RNA was isolated and subjected to Northern blot analysis using cDNA clones for human interstitial collagenase (MMP-1), 72-kDa type IV collagenase (MMP-2) and TIMP-2. UVA irradiation resulted in an increase in MMP-1 mRNA up to 2.3-fold, but did not stimulate MMP-2 or TIMP-2 mRNA expression. In contrast, ROS induced by the xanthine and XOD system resulted in a dose-related increase in the level of MMP-2 mRNA up to 2.1-fold and a decrease in the level of TIMP-2 mRNA by 49% in the same fibroblasts. Catalase, used as scavenger, essentially prevented the ROS-induced alterations in MMP-2 and TIMP-2 mRNA levels. These results suggest that ROS produced in the dermis may contribute to biological changes in the connective tissue matrix observed in photoaging skin by accelerating the MMP-2-related matrix degradation system.     

Fermentable metabolite of Zymomonas mobilis controls collagen reduction in photoaging skin by improving TGF-beta/Smad signaling suppression

Solar ultraviolet (UV) irradiation causes damages on human skin and premature skin aging (photoaging). UV-induced reduction of type I collagen in dermis is widely considered primarily induction of wrinkled appearance of photoaging skin. Type I procollagen synthesis is reduced under UV irradiation by blocking transforming growth factor-beta (TGF-beta)/Smad signaling; more specifically, it is down-regulation of TGF-beta type II receptor (T beta RII). Therefore, preventing UV-induced loss of T beta RII results decreased type I collagen reduction in photoaging skin. Zymomonas mobilis is an alcohol fermentable, gram-negative facultative anaerobic bacterium whose effect on skin tissue is scarcely studied. We investigated the protective effects of fermentable metabolite of Z. mobilis (FM of Z. mobilis) against reduction of type I procollagen synthesis of UV-induced down-regulation of T beta RII in human dermal fibroblasts FM of Z. mobilis was obtained from lyophilization of bacterium culture supernatant. The levels of T beta RII and type I procollagen mRNA in human dermal fibroblasts were measured by quantitative real-time RT-PCR, and T beta RII protein levels were assayed by western blotting. T beta RII, type I procollagen, and type I collagen proteins in human dermal fibroblasts or hairless mouse skin were detected by immunostaining. FM of Z. mobilis inhibited down regulation of T beta RII mRNA, and protein levels in UVB irradiated human dermal fibroblasts consequently recover reduced type I procollagen synthesis. These results indicate UVB irradiation inhibits type I procollagen synthesis by suppression of TGF-beta/Smad signaling pathway, and FM of Z. mobilis has inhibitory effect on UVB-induced reduction of type I procollagen synthesis. While short period UVB irradiation decreased both T beta RII and type I procollagen protein levels in hairless mouse skin, topical application of FM of Z. mobilis prevented this decrease. Wrinkle formation in hairless mouse skin surface was accelerated by continuous 5 month UVB irradiation along with a reduction of type I collagen in the dermis, but this change was prevented by topical application of FM of Z. mobilis. From this experimental data, it is suggested that FM of Z. mobilis is effective for suppression of wrinkle formation in photoaging skin by inhibition of type I procollagen synthesis reduction.     

Cutis laxa: analysis of metalloproteinases and extracellular matrix expression by immunohistochemistry and histochemistry

Upregulation of matrix metalloproteinases (MMPs) and downregulation of tissue inhibitors of metalloproteinases (TIMP) have been reported in cultured fibroblasts from patients with congenital cutis laxa (CL) or anetoderma. We determined the protein expressions of MMP-1, MMP-2, MMP-3, MMP-9, MMP-12, TIMP-1 and collagen I, collagen III in vivo, to confirm their roles in the pathogenesis of cutis laxa. The protein expression of the MMPs and collagens from skin lesions of CL were detected by immunohistochemistry and analyzed by image analysis software. Markedly increased MMP-1, MMP-2, MMP-3, MMP-9, MMP-12, TIMP-1 associated with alteration of elastic and collagen fibers were found in two cases of CL, whereas increased MMP-3, MMP-9, MMP-12 accompanying a degradation of elastic fibers were detected in the third case. These results suggest an elevated expression of MMPs may play a role in the evolution or genesis of CL.     

Fibroblasts surrounding melanoma express elevated levels of matrix metalloproteinase-1 (MMP-1) and intercellular adhesion molecule-1 (ICAM-1) in vitro

Tumour growth and metastasis involve the degradation of extracellular matrix components by matrix degrading enzymes produced by tumour cells and stromal fibroblasts. In this study, fibroblasts were obtained from biopsies on the border (TB) and 1 cm distant from the melanoma (TD) and cultured separately. Similar studies were performed with fibroblasts surrounding melanocytic nevi as control. The expression of matrix metalloproteinase-1 (MMP-1) mRNA and tissue matrix metalloproteinase inhibitor 1 (TIMP-1) were studied by Northern blot analysis. The activation antigen intercellular adhesion molecule-1 (ICAM-1) in TB-and TD-fibroblasts was investigated by flow cytometry. In melanoma, TB-fibroblasts showed an increased expression of MMP-1 mRNA mainly in fibroblasts obtained from tumours with extended invasive growth demonstrated by Clark level whereas the expression of the major specific inhibitor TIMP-1 was unaltered. In contrast, fibroblasts surrounding benign melanocytic nevi did not express elevated levels of MMP-1. The upregulation of MMP-1 in TB-fibroblasts compared to TD-fibroblasts was maintained during cultivation. Furthermore, MMP-1 mRNA expression and MMP-1 total protein amount in normal fibroblasts were increased by melanoma cell conditioned medium. We demonstrated an increased expression of ICAM-1 in TB-fibroblasts compared to TD-fibroblasts in vitro depending on the amount of inflammatory infiltrate in situ. The differences of ICAM expression disappeared during continued cell culture. These results support the idea that fibroblasts surrounding melanoma are activated and are possibly involved in the degradation of matrix proteins surrounding the tumour.     

Increase of collagen synthesis by obovatol through stimulation of the TGF-beta signaling and inhibition of matrix metalloproteinase in UVB-irradiated human fibroblast

BACKGROUND: Alterations of the extracellular matrix (ECM) is critical in the photo and age-damaged skin. Thus any compounds keep ECM can protected from photo and aged-damaged skin. ECM is predominantly composed of type I and type III collagens in the dermis. Transforming growth factor (TGF-beta)s play important roles in cellular biosynthesis of extracellular matrix. Activator protein 1 (AP-1) and Smad are significant factors that mediate TGF-beta. OBJECTIVE: We have investigated increasing effects of obovatol, a biphenolic compound isolated from leaves of Magnolia obovata on the collagen synthesis through stimulation of the TGF-beta signaling and inhibition of matrix metalloproteinase, thereby protect against from UV damages via maintain of collagen in the UVB irradiated human fibroblast cells. METHODS: The fibroblasts were pretreated with obovatol for 24h and then the cells were irradiated with UVB. UVB-exposed cells were further cultured for 24h. Type I procollagen, MMP-3, TGF-beta and Smad as well as phosphorylation of MAPK family expression were determined by Western blot. The activation of AP-1 was investigated using EMSA. The released type I procollagen and TGF-beta into cell culture medium were determined by Western blot after concentration of these proteins. RESULTS: The results showed that obovatol stimulated type I procollagen, TGF-beta, and Smad expression and inhibited matrix metalloproteinase-3 (MMP-3) in dose-dependent manner (1-5muM) in UVB-irradiated human fibroblast cells. Obovatol also inhibited UVB-induced activation of AP-1 and MAP kinases. CONCLUSION: These results suggest that obovatol increases collagen synthesis through stimulation of the TGF-beta signaling and inhibition of matrix metalloproteinase in UVB-irradiated human fibroblast, thus obovatol could be effective against photo-damaged skin.     

Retinoids suppress cysteine-rich protein 61 (CCN1), a negative regulator of collagen homeostasis, in skin equivalent cultures and aged human skin in vivo

Alterations in connective tissue collagen are prominent features of both chronologically aged and photoaged (ageing because of sun exposure) human skin. These age-related abnormalities are mediated in part by cysteine-rich protein 61 (CCN1). CCN1 is elevated in the dermis of both chronologically aged and photoaged human skin in vivo and promotes aberrant collagen homeostasis by down-regulating type I collagen, the major structural protein in skin, and promoting collagen degradation. Vitamin A and its metabolites have been shown to improve chronologically aged and photoaged skin by promoting deposition of new collagen and preventing its degradation. Here, we investigated regulation of CCN1 expression by retinoids in skin equivalent cultures and chronologically aged and photoaged human skin in vivo. In skin equivalent cultures, all-trans retinoic acid (RA), the major bioactive form of vitamin A in skin, significantly increased type I procollagen and reduced collagenase (matrix metalloproteinases-1, MMP-1). Addition of recombinant human CCN1 to skin equivalent cultures significantly reduced type I procollagen and increased MMP-1. Importantly, RA significantly reduced CCN1 expression in skin equivalent cultures. Topical treatment with retinol (vitamin A, 0.4%) for 7days significantly reduced CCN1 mRNA and protein expression in both chronologically aged (80+years) and photoaged human skin in vivo, compared to vehicle-treated skin. These data indicate that the mechanism by which retinoids improve aged skin, through increased collagen production, involves down-regulation of CCN1.     

Catalase restores the altered mRNA expression of collagen and matrix metalloproteinases by dermal fibroblasts exposed to reactive oxygen species

We investigated the effects of reactive oxygen species (ROS) on mRNA expression of proalpha1(I) collagen, proalpha1(III) collagen, matrix metalloproteinases-1 (MMP-1), 72 kDa type IV collagenase (MMP-2), and tissue inhibitor of metalloproteinase (TIMP-1) by normal human dermal fibroblasts in a novel three-dimensional culture. Fibroblasts exposed to ROS generated by the hypoxanthine-xanthine oxidase system revealed an increased mRNA expression of MMP-1 and MMP-2 with a maximum at 48 h and 72 h after exposure. A slight increase in the mRNA level of tissue inhibitor of metalloproteinase (TIMP-1) was observed. Increased protein level of MMP-1 and its collagenolytic activity and gelatinolytic activity of MMP-2 was comfirmed as well. In contrast, a time-dependent suppression of both proalpha1(I) and proalpha1(III) collagen mRNA expression was observed 12 h after ROS treatment with a maximum at 48 h and 72 h. Addition of catalase totally abrogated the ROS-induced alteration of these genes. Superoxide dismutase (SOD) abrogated only the increased mRNA expression of MMP-2. These results indicated that ROS mediates the induction of collagenases as well as the suppression of collagen synthesis by dermal fibroblasts in vitro. The biological alterations in collagen metabolism triggered by ROS may be responsible for the development of certain diseases or pathological changes such as photoaged human skin.     

辛伐他汀对体外培养系统性硬皮病患者的成纤维细胞增殖和胶原表达的影响

目的探讨辛伐他汀对系统性硬皮病患者皮肤成纤维细胞增殖、胶原分泌和Ⅰ型前胶原mRNA表达的影响。方法原代培养系统性硬皮病患者皮肤成纤维细胞,检测不同浓度的辛伐他汀作用于体外培养的成纤维细胞48h后细胞的存活力;观察不同浓度的辛伐他汀对细胞胶原分泌和Ⅰ型前胶原mRNA合成的影响。结果1.0×10-7,10-6,10-5和10-4mol/L浓度的辛伐他汀可以抑制患者皮肤成纤维细胞的增殖(P<0.05),并能显著减少成纤维细胞培养液中可溶性胶原的含量,与空白对照组比较,差异有显著性意义(P<0.05),且抑制作用随着药物浓度的增高而增强,具有明显的浓度依赖性。1.0×10-7～10-4mol/L的辛伐他汀可以显著的减少Ⅰ型前胶原蛋白mRNA的表达(P<0.05)。结论辛伐他汀对系统性硬皮病患者皮肤成纤维细胞的增殖及胶原的分泌均有显著的抑制作用,对细胞Ⅰ型前胶原蛋白mRNA的合成具有抑制作用,其为治疗硬皮病提供了理论基础。     

Basal and UV-induced MMP-1 expression are inhibited by p53 in human dermal fibroblasts

Ultraviolet (UV) triggers induction of matrix metalloproteinase-1 (MMP-1) and also induces the rapid appearance of p53 protein in the epidermis and dermal fibroblasts. However, little is known about the role of p53 on MMP-1 expression in human skin. Here, we investigated the effects of p53 on basal and UV-induced MMP-1 in human dermal fibroblasts. To verify the role of p53 on MMP-1 expression, adenoviral p53 (Ad-p53) gene was infected to human dermal fibroblasts. Our results showed that basal and UV-induced MMP-1 expression was prevented by Ad-p53. In contrast, p53 inhibitor, pifithrin-alpha augmented the UV-induced MMP-1 expression. On the other hand, p53 activator, etoposide, decreased the MMP-1 expression in both normal and p53-overexpressed cells. In addition, MMP-1 expression was not changed by etoposide and/or pifithrin-alpha in HaCaT cells, which have mutation of p53. Taken together, we suggest that p53 inhibits basal and UV-induced MMP-1 expression in human dermal fibroblasts.