Blood glucose fluctuation affects skin collagen metabolism in the diabetic mouse by inhibiting the mitogen‐activated protein kinase and Smad pathways

Background. We recently reported that in mice, blood glucose fluctuations (BGF) produced more detrimental effects on skin structure and function than did diabetes alone. Aim. To determine whether treatment of BGF changes the collagen metabolism in the skin of diabetic mice, and to explore its possible molecular mechanism further. Methods. The study used diabetic and BGF animal models. Immunohistochemistry, western blotting and real‐time PCR analysis were used to detect the expression of type I collagen, matrix metalloproteinase (MMP)‐1, MMP‐2 and MMP‐13, tissue inhibitor of metalloproteinase (TIMP)‐1, extracellular signal‐regulated kinase, p38, and Smad2/3. The activities of mitogen‐activated protein kinase (MAPK) and Smad signal molecules were also detected by western blotting, and the skin fibroblast ultrastructure was examined using an electron microscope. Results. BGF treatment produced a twofold reduction in type I collagen synthesis compared with diabetes‐only mice. Expression of MMP‐1, MMP‐2 and MMP‐13 increased markedly in the BGF‐treated mice, but TIMP‐1 expression was strongly downregulated by the BGF treatment. There was also evidence of higher levels of apoptosis of skin fibroblasts after BGF treatment. Conclusions. BGF treatment can affect collagen production in the skin of diabetic BGF mice by inhibiting collagen synthesis and increasing collagen degradation. Furthermore, both MAPK and Smad signalling pathways seem to play a role in the inhibition of collagen production in diabetic mice treated with BGF.     

Skin fragility in obese diabetic mice: possible involvement of elevated oxidative stress and upregulation of matrix metalloproteinases

The purpose of this study was to test the hypothesis that obese diabetic mice exhibit marked skin fragility, which is caused by increased oxidative stress and increased matrix metalloproteinase (MMP) gene expression in the subcutaneous adipose tissue. Scanning electron microscopy of skin samples from Tsumura-Suzuki obese diabetic (TSOD) mice revealed thinner collagen bundles, and decreased density and convolution of the collagen fibres. Furthermore, skin tensile strength measurements confirmed that the dorsal skin of TSOD mice was more fragile to tensile force than that of non-obese mice. The mRNA expressions of heme oxygenase 1 (Hmox1), a marker of oxidative stress, Mmp2 and Mmp14 were increased in the adipose tissue of TSOD mice. Antioxidant experiments were subsequently performed to determine whether the changes in collagen fibres and skin fragility were caused by oxidative stress. Strikingly, oral administration of the antioxidant dl-α-tocopherol acetate (vitamin E) decreased Hmox1, Mmp2 and Mmp14 mRNA expressions, and improved the skin tensile strength and structure of collagen fibres in TSOD mice. These findings suggest that the skin fragility in TSOD mice is associated with dermal collagen damage and weakened tensile strength, and that oxidative stress and MMP overexpression in the subcutaneous adipose tissue may, at least in part, affect dermal fragility via a paracrine pathway. These observations may contribute to novel clinical interventions, such as dietary supplementation with antioxidants or application of skin cream containing antioxidants, which may overcome skin fragility in obese patients with diabetes.     

Topical all-trans retinoic acid stimulates collagen synthesis in vivo

Histochemical and ultrastructural studies demonstrate that topical all-trans retinoic acid (RA) stimulates the deposition of a subepidermal band of collagen in photoaged hairless mice. The aim of this study was to examine the effect of RA treatment on collagen synthesis using biochemical and immunochemical techniques. Albino hairless mice were irradiated three times a week for 10 weeks with four minimal erythema doses of UVB from Westinghouse FS-40 bulbs. In the post-UV period, mice were either nontreated or treated with 0.05% RA or the ethanol-propylene glycol vehicle for up to 10 weeks. Antibodies against the aminopropeptide (AP) of type III procollagen were used in immunofluorescence microscopy and radioimmunoassay techniques. The AP of type III collagen is normally present throughout the dermis and in areas of active collagen synthesis (i.e., the dermal-epidermal junction). In this study, a similar distribution was seen in all untreated and vehicle-treated mice, and in mice treated with RA for 2, 4, and 6 weeks. However, increased staining, in a subepidermal band, was detected in the 8-week RA-treated skin. This region became intensely fluorescent to a depth of 100 mu in the 10-week RA-treated skins. As determined by radioimmunoassay, the content of the AP of type III procollagen increased twofold with 10-week RA treatment. Because the ratio of type I to type III collagens remained constant in treated and untreated skins, it is reasonable to assume that the content of type I collagen increased in proportion to type III collagen in RA-treated skins.     

Retinoids in veterinary dermatology

The retinoids are a class of pharmacologic compounds. Some occur naturally (vitamin A, β-carotene), and others have been synthesized (13-cis-retinoic acid, etretinate, the arotinoids); all of these compounds have profound effects on epithelial tissues. Naturally occurring vitamin A (retinol) and its metabolites, retinoic acid and retinal, are essential requirements for reproduction, vision, and normal growth, differentiation, and maintenance of epithelial tissues.¹ Medical use of vitamin A began in the 1920s based on the recognition of clinical and histologic similarities between vitamin A-deficient animals and certain dyskeratotic skin conditions. Subsequently, interest in the possible role of vitamin A in cancer prevention developed from the observation of an increased incidence of certain types of cancer in vitamin A-deficient human populations and in experimental conditions with laboratory rats. The therapeutic usefulness of vitamin A was limited by its toxicity at pharmacologic doses. In the late 1960s, researchers actively began to develop synthetic analogs of vitamin A, looking for compounds with increased therapeutic indices, particularly with reference to cancer prevention.¹     

MDI 301, a non-irritating retinoid,induces changes in human skin that underlie repair

Previous studies have demonstrated that all-trans retinoic acid (RA) increases collagen production and decreases matrix metalloproteinase (MMP) activity in organ-cultured human skin. Decreased MMP activity is associated with up-regulation of tissue inhibitor of metalloproteinase-1 (TIMP-1). These changes are accompanied by a hyperplastic response in the epidermis. Here we show that a synthetic picolinic ester-substituted retinoid (designated as MDI 301) has comparable effects to those of RA in regard to these activities. What makes these findings of interest is that RA also stimulates elaboration of several pro-inflammatory cytokines and up-regulates leukocyte adhesion molecules in organ-cultured skin. MDI 301 does not induce such changes or is much less active. In a past study we showed that while RA was irritating to the skin of topically treated hairless mice, MDI 301 was essentially non-irritating under the same conditions [Varani et al. (2003) Arch. Dermatol Res 295:255–262]. Taken in conjunction with the findings from the past study, the present data suggest that MDI 301 will be similar to RA in capacity to repair damaged skin, but will be effective under conditions that are not irritating. These findings, thus, suggest that retinoid efficacy and clinically relevant irritancy are not inextricably linked. Potential for efficacy under conditions in which irritation is not observed is a strong rationale for further development of MDI 301 as a skin-repair agent.     

Effects of long-term retinoic acid treatment on epidermal differentiation in vivo: specific modifications in the programme of terminal differentiation

Summary To investigate the effects of long-term all-trans-retinoic acid (RA) treatment on epidermal differentiation in vivo , rhino mice were treated topically with 0.005% RA, and their epidermis was analysed histologically and biochemically after 5, 13 and 26 weeks of treatment. Effects of RA were observed first in the living layers of the epidermis, and then in the non-viable stratum corneum. Five weeks of topical RA led to thickening of the spinous and granular compartments, induction of keratins K6, K16 and K17, and suppression of filaggrin expression. After 13 and 26 weeks of RA treatment, the number of anucleate cornified cell layers remained similar to controls, but additional changes in histology and protein expression were observed. The results showed that prolonged administration of topical RA induced epidermal hyperproliferation, but did not suppress differentiation, in contrast to results observed in keratinocyte cultures. However, the distinct histological and biochemical changes observed in the spinous, granular and cornified layers of RA-treated skin after 26 weeks of treatment, suggested that the progeny of RA-treated basal cells undergo a modified programme of terminal differentiation. Considering the present data together with results of previous in vivo studies, we propose that long-term topical RA treatment retards, or specifically modulates, the later stages in epidermal differentiation, or programmed cell death.     

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.     

他扎罗汀和窄谱中波紫外线对银屑病基质金属蛋白酶13表达的影响

【摘要】 目的 检测基质金属蛋白酶13（MMP13）在银屑病患者中的表达,评估他扎罗汀和窄谱中波紫外线（NB-UVB）对银屑病样皮炎小鼠MMP13表达的影响。方法 收集2019年5 - 8月就诊于天津医科大学总医院的18例银屑病患者皮损组织和10例健康人正常皮肤组织及所有受试者血清。将25只SPF级BALB/c雄性小鼠随机分成对照组、咪喹莫特组、咪喹莫特 + NB-UVB组、咪喹莫特 + 他扎罗汀组和咪喹莫特 + 他扎罗汀 + NB-UVB组,每组5只。分别给予小鼠背部皮肤不同处理,除对照组外,其余各组进行银屑病样皮炎造模处理,造模时间为7 d,造模成功后,第8天早上取小鼠眼球血,并使用脱颈法处死后,切取背部皮损组织。HE染色观察皮损处表皮厚度和病理变化,免疫组化检测表皮MMP13表达水平,ELISA检测血清MMP13含量。两组比较采用独立样本t检验,多组间比较采用单因素方差分析,组间两两比较用LSD检验,计数资料采用χ2检验比较。结果 银屑病患者皮损处MMP13呈强阳性表达,表皮和血清MMP13水平［84.11 ± 17.16、（13.29 ± 3.95） μg/L］显著高于健康对照组［11.98 ± 4.08、（7.46 ± 1.58） μg/L,均P < 0.01］。与对照组表皮厚度［（1.26 ± 0.04） μm］、表皮和血清MMP13水平［25.40 ± 2.34、（185.76 ± 7.22） μg/L］比较,咪喹莫特组表皮厚度［（7.93 ± 0.59） μm］明显增加,表皮和血清中MMP13水平［147.14 ± 5.53、（215.98 ± 15.17） μg/L］也显著增加（均P < 0.01）。与咪喹莫特组比较,咪喹莫特 + 他扎罗汀组、咪喹莫特 + NB-UVB组、咪喹莫特 + 他扎罗汀 + NB-UVB组表皮厚度均下降［分别为（3.56 ± 0.37）、（3.83 ± 0.39）、（2.14 ± 0.34） μm,均P < 0.05］,表皮中MMP13表达减弱（分别为120.42 ± 3.23、91.08 ± 0.46、71.12 ± 7.11,均P < 0.05）,且血清MMP13含量下降［分别为（197.39 ± 3.92）、（196.13 ± 11.76）、（183.21 ± 14.99） μg/L,均P < 0.05］。结论 MMP13蛋白表达水平在银屑病患者皮损及血清中增高;他扎罗汀和NB-UVB治疗后银屑病样皮炎小鼠皮损和血清中MMP13下降。MMP13可能参与银屑病的发展,他扎罗汀和NB-UVB可能通过减少MMP13的表达而抑制银屑病发展。     

Topical retinoic acid changes the epidermal cell surface glycosylation pattern towards that of a mucosal epithelium

Topical all-trims retinoic acid (RA) produces a number of epidermal changes which are indistinguishable from those observed following treatment with a local irritant, namely sodium lauryl sulphate (SI. S). This observation has led to criticism that the efficacy of RA in disorders such as photoageing. Is merely a result of irritancy. In stratified epithelia, the cellular differentiation process is characterized by a stepwise synthesis of cell surface carbohydrates, and each type of stratified epithelium has its own specific pattern of carbohydrate expression. Glycosyltransferases, which are responsible for carbohydrate synthesis, are influenced by retinoids. Thus, we investigated whether epidermal cell surface glycosylation is altered in skin treated with topical RA, and contrasted it with changes induced by topical SLS Skin biopsies were obtained from seven normal volunteers who had been treated, on three separate areas of buttock skin, with single applications of 0·1% RA. 2% SLS, or vehicle creams, followed by 4-day occlusion. Biopsies were assessed immunohistologically using highly specific monoclonal antibodies to cell surface carbohydrates (types 1, 2 and 3 chain structures), previously demonstrated in the epidermis and in oral mucosal epithelium. Although type 1 chain structures were not demonstrated in any of the samples, the distribution of type 2 and 3 chain structures in RA-treated epidermis was altered towards that seen in a mucosal epithelium. T antigen, a mucin-type cell surface carbohydrate structure normally expressed throughout the epidermis, was only observed in the granular layer of RA-treated epidermis-a feature of mucosal epithelia. Le^y, normally only seen in non-keratinized buccal epithelium, was strongly expressed in RA-treated epidermis. In contrast, the glycosylation pattern of the SLS-treated epidermis was not significantly different from that observed after vehicle treatment. Thus, RA treatment converts normal stratified epithelium towards the phenotype of mucosal epithelium with a decrease in T antigen and a concomitant increase in Le^y. These changes the not observed following treatment with SLS and identify an important difference between RA effects and irritancy.     

Elevated expression of extracellular matrix metalloproteinase inducer (CD147) and membrane-type matrix metalloproteinases in venous leg ulcers

BACKGROUND: Matrix metalloproteinases (MMPs) contribute to matrix remodelling in venous leg ulcers. Extracellular MMP inducer (EMMPRIN; CD147) has been reported to increase MMP expression, and membrane type 1 MMP (MT1-MMP) has been implicated in the activation of MMPs. OBJECTIVES: To examine whether and to what degree EMMPRIN, MMP-2, MT1-MMP and membrane type 2 MMP (MT2-MMP) are expressed in venous leg ulcers as well as the association with MMP activity. METHODS: EMMPRIN, MMP-2, MT1-MMP and MT2-MMP were analysed by zymography and immunohistochemistry in biopsies from healthy skin and lesional tissue from venous leg ulcers. RESULTS: Zymography provided direct evidence of increased proteolytic activity of MMP-2 in lesional skin in comparison with healthy controls. Immunostaining showed intense expression of EMMPRIN, MMP-2, MT1-MMP and MT2-MMP in dermal structures of venous leg ulcers, whereas only EMMPRIN and MMP-2 showed elevated expression in perivascular regions. Our findings indicate that venous leg ulcers are characterized by elevated expression of EMMPRIN, MMP-2, MT1-MMP and MT2-MMP. The immunohistological findings of skin alterations reflect the dynamic process of activation of soluble and membrane-bound MMPs, which may be highly induced by EMMPRIN. CONCLUSIONS: These data suggest for the first time that membrane-bound MMPs may favour enhanced turnover of the extracellular matrix and support unrestrained MMP activity in venous leg ulcers.     

Retinoic acid induces cyclic changes in epidermal thickness and dermal collagen and glycosaminoglycan biosynthesis rates

The effects of daily topical application onto guinea pig ears of a therapeutic concentration of all trans-retinoic acid (RA) on epidermal thickness and dermal collagen and glycosaminoglycan (GAG) biosynthesis rates were studied during a 40-day period. Clinically, the RA-treated skin became erythematous and scaly beginning at 5-6 days, conditions which persisted throughout the experiment. The epidermis became thickened and hyperplastic with marked psoriasi-form histologic features, and the phenomenon was dependent on RA concentration. The initial hyperplasia resulted from a transient 4-fold increase in epidermal basal cell replication during the first 3-4 days, as shown by the rise and fall of [3H]thymidine labeling index which preceded the hyperplasia. The extent of epidermal hyperplasia as measured by epidermal thickness was not constant throughout the 40-day treatment period, but exhibited maxima on days 11, 25, and 36. These maxima were followed by periods of decreased thickness, although the minima were always greater than the untreated controls. Retinoic acid induced similar temporal cycles in GAG and collagen biosynthesis rates, but the collagen cycles occurred at different times with maxima on days 6, 20, and 34. After 8 weeks' treatment, the blood flow rates in the ear microcirculation (laser Doppler photometry) were increased 81% above that of the water-treated controls. The demonstration of these RA-induced cyclic changes in epidermal hyperplasia and dermal fibroblast biosynthetic activities have revealed the presence of control mechanisms in these tissues which normally operate to maintain tissue homeostasis.     

Potential protective effect of fresh grown unicellular green algae component (resilient factor) against PMA- and UVB-induced MMP1 expression in skin fibroblasts

Solar UV radiation damages human skin, affecting skin tone and resiliency, and leading to premature ageing (photoageing). Skin damage by oxidants may lead to activation of PKC, thus increasing matrix metalloproteinase (MMPs) expression and collagen degradation. Administration of Chlorella has been shown to play some biochemical functions as well as in vitro inhibition of MMP1 activity. MMP1 secretion was evaluated following PMA treatment or UVB irradiation in the presence of Resilient Factor (RF, aqueous extract fraction of Chlorella), vitamin C, or vitamin E in human skin fibroblasts. Expression levels of MMP1 and elastin protein and of MMP1, TIMP1, and pro-collagen mRNA were also investigated. PMA-induced MMP1 production, protein, and gene expression were suppressed in the presence of RF. Elastin protein diminished after UVB exposure and RF treatment appeared able to counteract the effect of UVB irradiation. Our results also suggest that RF may increase pro-collagen mRNA expression following UVB exposure. This study shows that application of RF prevents MMP1 production via the inhibition of protein and gene expression. In addition, RF prevents the UVB-suppressed elastin protein and pro-collagen gene expression. These findings indicate that RF may exert a protective effect against UVB irradiation-induced damage in the skin.     

Elevated matrix metalloproteinase-2 and -3 production from human diabetic dermal fibroblasts

BACKGROUND: Diabetic foot ulcers are characterized by elevated levels of matrix metalloproteinases (MMP), which could lead to excessive matrix breakdown and disruption to healing. It is unknown if this elevation is a function of wound healing, or if it is present within normal skin and a primary contributor to the increased risk of impaired healing. OBJECTIVES: To determine whether diabetic fibroblasts from unwounded skin show elevated MMP production compared with their nondiabetic counterparts. PATIENTS AND METHODS: Circular skin biopsies (4 mm diameter) were taken from the inside upper arm of four controls without diabetes and from four subjects with insulin-treated diabetes. Fibroblasts were incubated for a further 72 h and conditioned medium was collected and stored at -20 degrees C. The conditioned medium was assessed by gelatin zymography and Western blotting for MMP-2 and MMP-3. RESULTS: Diabetic dermal fibroblasts showed significantly elevated production of MMP-2 (P < 0.05) and pro-MMP-3 (P < 0.05) when compared with their nondiabetic counterparts. CONCLUSIONS: Dermal fibroblasts from normal unwounded skin are characterized by increased MMP production and this may be a primary contributing factor to the increased risk of nonhealing foot ulceration in diabetes.     

Epidermal development and wound healing in matrix metalloproteinase 13-deficient mice

Degradation of the extracellular matrix, which is an indispensable step in tissue remodelling processes such as embryonic development and wound healing of the skin, has been attributed to collagenolytic activity of members of the matrix metalloproteinase family (MMPs). Here, we employed mmp13 knockout mice to elucidate the function of MMP13 in embryonic skin development, skin homeostasis, and cutaneous wound healing. Overall epidermal architecture and dermal composition of non-injured skin were indistinguishable from wild-type mice. Despite robust expression of MMP13 in the early phase of wound healing, wild-type and mmp13 knockout animals did not differ in their efficiency of re-epithelialization, inflammatory response, granulation tissue formation, angiogenesis, and restoration of basement membrane. Yet, among other MMPs also expressed during wound healing, MMP8 was found to be enhanced in wounds of MMP13-deficient mice. In summary, skin homeostasis and also tissue remodelling processes like embryonic skin development and cutaneous wound healing are independent of MMP13 either owing to MMP13 dispensability or owing to functional substitution by other collagenolytic proteinases such as MMP8.     

Skin disruption is associated with indomethacin‐induced small intestinal injury in mice

One mechanism by which non‐steroidal anti‐inflammatory drugs (NSAIDs) cause intestinal injury is by inducing matrix metalloproteinases (MMPs) that degrade and remodel the extracellular matrix. In addition to the intestinal mucosa, MMPs are expressed in the skin and can be activated by mast cell‐secreted tryptase. We therefore investigated whether intestinal injury resulting from treatment with the NSAID indomethacin induced MMPs in the skin of mice and caused an associated disruption of skin function. Hairless mice and mast cell‐deficient mice were administered indomethacin, after which damage to the jejuna and skin was assessed with immunohistochemistry and Western blotting. The plasma concentration of inflammatory mediators was assessed to evaluate potential pathways for signalling skin disruption in response to intestinal injury. In hairless mice with intestinal injury, transepidermal water loss (TEWL) was higher and skin hydration was lower than in control mice. The expression levels of mast cells, tryptase, MMP‐1 and MMP‐9 were also increased, with concurrent degradation of types I and IV collagen. In contrast, no changes in skin TEWL or skin hydration were observed in mast cell‐deficient mice with indomethacin‐induced intestinal injury. In all mice evaluated, the plasma concentrations of IgE, IgA, histamine and TNF‐α were increased in response to indomethacin treatment. Skin disruption was strongly associated with indomethacin‐induced small intestinal injury, and the activation of mast cells and induction of tryptase, MMP‐1 and MMP‐9 are critical to this association.     

Cytokeratins 16 and 10 bind to retinoic acid covalently in skin tissue of mice

Background Retinoic acid (RA) has various biological effects in mammalian cells and tissues. In epidermal cells, RA is an inhibitor of differentiation to the squamous phenotype. The molecular mechanisms underlying the effects of RA on epidermal cells and other cell types are mediated by RA nuclear receptors and retinoylation (acylation by RA) of proteins. Objectives To understand the components responsible for RA effects via RA nuclear receptors and retinoylation. Methods We examined for the first time RA‐binding proteins in mouse skin in vivo by immunoblotting using anti‐RA monoclonal antibodies and identified by matrix‐assisted laser desorption ionization–time of flight mass spectrometry. Results We identified eight RA‐binding proteins in the skin of hairless mice that were increased by topical RA treatment. Three of these proteins were identified as cytokeratin 10, cytokeratin 16 and serum albumin. Conclusion These results raise the possibility that RA binding to cytokeratins in vivo may be involved in the effect of RA on keratinocytes in mouse skin.     

Decorin‐expressing adenovirus decreases collagen synthesis and upregulates MMP expression in keloid fibroblasts and keloid spheroids

Decorin is a natural transforming growth factor‐β1 (TGF‐β1) antagonist. Reduced decorin synthesis is associated with dermal scarring, and increased decorin expression appears to reduce scar tissue formation. To investigate the therapeutic potential of decorin for keloids, human dermal fibroblasts (HDFs) and keloid‐derived fibroblasts (KFs) were transduced with decorin‐expressing adenovirus (dE1‐RGD/GFP/DCN), and we examined the therapeutic potential of decorin‐expressing Ad for treating pathologic skin fibrosis. Decorin expression was examined by immunofluorescence assay on keloid tissues. HDFs and KFs were transduced with dE1‐RGD/GFP/DCN or control virus, and protein levels of decorin, epidermal growth factor receptor (EGFR) and secreted TGF‐β1 were assessed by Western blotting and ELISA. And type I and III collagen, and matrix metalloproteinase‐1 (MMP‐1) and matrix metalloproteinase‐3 (MMP‐3) mRNA levels were measured by real‐time RT‐PCR. Additionally, we immunohistochemically investigated the expression levels of the major extracellular matrix (ECM) proteins in keloid spheroids transduced with dE1‐RGD/GFP/DCN. Lower decorin expression was observed in the keloid region compared to adjacent normal tissues. After treatment with dE1‐RGD/GFP/DCN, secreted TGF‐β1 and EGFR protein expressions were decreased in TGF‐β1‐treated HDFs and KFs. Also, type I and III collagen mRNA levels were decreased, and the expression of MMP‐1 and MMP‐3 mRNA was strongly upregulated. In addition, the expression of type I and III collagen, fibronectin and elastin was significantly reduced in dE1‐RGD/GFP/DCN‐transduced keloid spheroids. These results support the utility of decorin‐expressing adenovirus to reduce collagen synthesis in KFs and keloid spheroid, which may be highly beneficial in treating keloids.