Increased collagen synthesis accompanying elevated m-RNA levels in cultured Werner's syndrome fibroblasts

The HEDGEHOG-GLI1 pathway is important for fibroproliferative properties in keloids and as a candidate therapeutic target

Keloids are benign fibroproliferative skin tumors caused by aberrant wound healing that can negatively impact patient quality of life. The lack of animal models has limited research on pathogenesis or developing effective treatments, and the etiology of keloids remains unknown. Here, we found that the characteristics of stem-like cells from keloid lesions and the surrounding dermis differ from those of normal skin. Furthermore, the HEDGEHOG (HH) signal and its downstream transcription factor GLI1 were upregulated in keloid patient-derived stem-like cells. Inhibition of the HH-GLI1 pathway reduced the expression of genes involved in keloids and fibrosis-inducing cytokines, including osteopontin. Moreover, the HH signal inhibitor vismodegib reduced keloid reconstituted tumor size and keloid-related gene expression in nude mice and the collagen bundle and expression of cytokines characteristic for keloids in ex vivo culture of keloid tissues. These results implicate the HH-GLI1 pathway in keloid pathogenesis and suggest therapeutic targets of keloids.

Triple Cross-Linked Hyaluronic Acid Based on Tri-Hyal Technique Has More Durable Effect on Dermal Renewal

Background

Hyaluronic acid (HA)-based fillers are applied to treat facial wrinkles and volume loss. Many efforts have been made to improve properties of HA to prolong the duration in aesthetic indications. A new cross-linking technique called “Tri-Hyal”, could make HAs to achieve desired rheological characteristics. HAs synthesized by Tri-Hyal are triple cross-linked and sustained-release, which could increase duration of promoting skin rejuvenation after injection.

Purpose

To evaluate the efficiency and persistence of HAs with Tri-Hyal on skin rejuvenation and further investigate underlying mechanisms, we compared the performances of cross-linked HA (AF) based on Tri-Hyal with another highly acceptable HA filler (Res) in vivo and in vitro.

Methods

Male BALB/c mice were divided into three groups, treated with AF, Res and vehicle, respectively. Skin biopsies were taken on day 0, 30, 90 and 180 after injection and hematoxylin and eosin (H&E), Masson’s trichrome (MT), immunohistochemical (IHC) stainings for CD31, TGF-β and MMP9 were performed. EdU incorporation, cell counting kit-8 (CCK-8), SA-β-Gal staining and activity were measured by biochemical analysis. RFP-GFP-LC3 adeno virus was used for autophagic flux detection. Protein levels of CD44, P62 and LC3I/II were detected by Western blot. Reactive oxygen species (ROS) level was detected by flow cytometry with DCFH-DA probe.

Results

The AF synthesized by Tri-Hyal showed persistent dermal structural correction without attenuation up to 6 months, which was illustrated by skin thickness, formation of elastic fibers and vascular density. Consistently, in fibroblasts the AF improved cell proliferation and slowed the senescent in vitro. Furthermore, it promoted cellular autophagy to reduce ROS level, which would account for its function in skin renewal.

Conclusion

The HA with Tri-Hyal could stimulate the production of extracellular matrix components more persistently than traditional HA fillers. In terms of mechanisms, it delayed senescence in dermal fibroblasts through reducing oxidative stress mediated by induction of autophagy.

MiR-3613-3p inhibits hypertrophic scar formation by down-regulating arginine and glutamate-rich 1

Hypertrophic scar (HS) is a severe skin disorder characterized by excessive extracellular matrix production and abnormal function of fibroblasts. Recent studies have demonstrated that microRNAs (miRNAs) play critical roles in HS formation. This study aims to investigate the role of miR-3613-3p in the formation of HS. The mRNA and miRNA levels were measured by quantitative RT-PCR analysis. The protein levels were examined by Western blot assay. Cell proliferation was determined by Cell Counting Kit-8 assay. The Caspase-3 and Caspase-9 activities were measured using flow cytometry assay. Dual-luciferase activity reporter assay and mRNA-miRNA pulldown assay were conducted to validate the target of miR-3613-3p. miR-3613-3p was downregulated, while arginine and glutamate-rich 1 (ARGLU1) was upregulated in HS fibroblasts (HSFs) and tissues. Overexpression of miR-3613-3p or knockdown of ARGLU1 markedly inhibited the expression of extracellular matrix (ECM) production-associated proteins and promoted Caspase-3 and Caspase-9 activations in HSFs. ARGLU1 was further identified as a direct target of miR-3613-3p. Restoration of ARGLU1 abrogated the suppressive effect of miR-3613-3p on cell proliferation and ECM protein expression of HSFs. Our results demonstrated that miR-3613-3p inhibited HS formation via targeting ARGLU1, which may provide potential therapeutic targets for the management of HS.

Regulatory effects of electronic beam irradiation on mir-21/smad7-mediated collagen I synthesis in keloid-derived fibroblasts

Keloid scarring is an abnormal pathological scar characterized by excessive fibro proliferation and extracellular matrix deposition. Electronic beam irradiation is commonly used with surgical removal to control high recurrence rates of keloid scarring; however, the mechanism remains unknown. In this study, we used keloid-derived primary fibroblasts (KF) as the cell model, and a dose of 15 Gy energy, followed by quantitative PCR (qPCR), western blotting and gene overexpression/knock down techniques were used to reveal the molecular mechanisms affected by electronic beam irradiation. We found that mir-21 was highly expressed in KF and was downregulated by irradiation. We also showed that smad7 was a direct target of mir-21. Moreover, the expression level of smad7 was low in KF and upregulated by irradiation. We also found that smad7 controls Col-1 synthesis by mediating p38 phosphorylation, and this process was affected by electronic beam irradiation. The regulatory effect of electronic beam irradiation on the expression of mir-21, smad7, p38, p-p38 and Col-1 could be partly restored by mir-21 overexpression achieved by mir-21 mimic transfection. In conclusion, our data demonstrated that mir-21/smad7 regulated Col-1 expression in KF and that electronic beam irradiation was capable of decreasing Col-1 production by modifying mir-21/smad7-mediated p38 activation. This is the first report identifying the effects of electronic beam irradiation on miRNAs, providing a novel strategy to discover the molecular mechanisms of radiotherapy.

Summary: Using primary keloid-derived fibroblasts, we demonstrate that electronic beam irradiation inhibits the recurrence of keloid scarring by suppressing collagen I expression via mir-21/smad7-mediated p38 activation.

MicroRNA-143-3p inhibits hyperplastic scar formation by targeting connective tissue growth factor CTGF/CCN2 via the Akt/mTOR pathway

Post-traumatic hypertrophic scar (HS) is a fibrotic disease with excessive extracellular matrix (ECM) production, which is a response to tissue injury by fibroblasts. Although emerging evidence has indicated that miRNA contributes to hypertrophic scarring, the role of miRNA in HS formation remains unclear. In this study, we found that miR-143-3p was markedly downregulated in HS tissues and fibroblasts (HSFs) using qRT-PCR. The expression of connective tissue growth factor (CTGF/CCN2) was upregulated both in HS tissues and HSFs, which is proposed to play a key role in ECM deposition in HS. The protein expression of collagen I (Col I), collagen III (Col III), and α-smooth muscle actin (α-SMA) was obviously inhibited after treatment with miR-143-3p in HSFs. The CCK-8 assay showed that miR-143-3p transfection reduced the proliferation ability of HSFs, and flow cytometry showed that either early or late apoptosis of HSFs was upregulated by miR-143-3p. In addition, the activity of caspase 3 and caspase 9 was increased after miR-143-3p transfection. On the contrary, the miR-143-3p inhibitor was demonstrated to increase cell proliferation and inhibit apoptosis of HSFs. Moreover, miR-143-3p targeted the 3'-UTR of CTGF and caused a significant decrease of CTGF. Western blot demonstrated that Akt/mTOR phosphorylation and the expression of CTGF, Col I, Col III, and α-SMA were inhibited by miR-143-3p, but increased by CTGF overexpression. In conclusion, we found that miR-143-3p inhibits hypertrophic scarring by regulating the proliferation and apoptosis of human HSFs, inhibiting ECM production-associated protein expression by targeting CTGF, and restraining the Akt/mTOR pathway.

Tissue Inhibitor of Metalloproteinase-2 Suppresses Collagen Synthesis in Cultured Keloid Fibroblasts

BACKGROUND

Keloids are defined as a kind of dermal fibroproliferative disorder resulting from the accumulation of collagen. In the remodeling of extracellular matrix, the balance between matrix metalloproteinases (MMPs) and the tissue inhibitors of metalloproteinases (TIMPs) is as critical as the proper production of extracellular matrix. We investigate the role of TIMPs and MMPs in the pathogenesis of keloids and examine the therapeutic potential of TIMP-2.

METHODS

The expression of TIMPs and MMPs in most inflamed parts of cultured keloid fibroblasts (KFs) and peripheral normal skin fibroblasts (PNFs) in the same individuals and the reactivity of KFs to cyclic mechanical stretch were analyzed by quantitative real-time polymerase chain reaction and enzyme-linked immunosorbent assay (n = 7). To evaluate the effect of treating KFs with TIMP-2, collagen synthesis was investigated by quantitative real-time polymerase chain reaction and enzyme-linked immunosorbent assay, and microscopic analysis was used to examine the treatment effects of TIMP-2 on ex vivo cultures of keloid tissue (n = 6).

RESULTS

TIMP-2 was downregulated in cultured KFs compared with PNFs in the same individuals, and the reduction in TIMP-2 was exacerbated by cyclic mechanical stretch. Administration of TIMP-2 (200 or 300 ng/mL) significantly suppressed expression of Col1A2 and Col3A1 mRNA and collagen type I protein in KFs. TIMP-2 also significantly reduced the skin dermal and collagen bundle thickness in ex vivo cultures of keloid tissue.

CONCLUSION

These results indicated that downregulation of TIMP-2 in KFs is a crucial event in the pathogenesis of keloids, and the TIMP-2 would be a promising candidate for the treatment of keloids.

Comparative study of microRNA profiling in keloid fibroblast and annotation of differential expressed microRNAs

Keloids are tumor-like skin scars that grow as a result of the aberrant healing of skin injuries, with no effective treatment. The molecular mechanism underlying keloid pathogenesis is still largely unknown. In this study, we compared microRNA (miRNA) expression profiles between keloid-derived fibroblasts and normal fibroblasts (including fetal and adult dermal fibroblasts) by miRNA microarray analysis. We found that the miRNA profiles in keloid-derived fibroblasts are different with those in normal fibroblasts. Nine miRNAs were differentially expressed, six of which were significantly up-regulated in keloid fibroblasts (KFs), including miR-152, miR-23b-3p, miR-31-5p, miR-320c, miR-30a-5p, and hsv1-miR-H7, and three of which were significantly down-regulated, including miR-4328, miR-145-5p, and miR-143-3p. Functional annotations of differentially expressed miRNA targets revealed that they were enriched in several signaling pathways important for scar wound healing. In conclusion, we demonstrate that the miRNA expression profile is altered in KFs compared with in fetal and adult dermal fibroblasts, and the expression profile may provide a useful clue for exploring the pathogenesis of keloids. miRNAs might partially contribute to the etiology of keloids by affecting several signaling pathways relevant to scar wound healing.

Development of an in vitro model of menopause using primary human dermal fibroblasts

OBJECTIVE

To overcome the current lack of in vitro models to specifically reproduce hormonal skin ageing in women, and in search of active ingredients with innovative efficacy claim for cosmetic skin care, we developed a cell culture-based model by simulating menopause's hormonal decline and assessed several parameters of collagen metabolism.

METHODS

Human dermal fibroblasts were incubated with media containing 17β-oestradiol, progesterone, dehydroepiandrosterone, growth hormone and insulin-like growth factor-1 at concentrations corresponding to those of non-menopausal women's sera and then of menopausal women's sera. We measured cell proliferation [by 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT)], matrix metalloproteinase-1 and metalloproteinase-3 (MMPs) release (by enzyme-linked immunosorbent assay - ELISA), total collagen deposition (by Sirius red staining), types I and III collagen deposition (by ELISA), and types I and III procollagen gene expression (by real-time q-RT-PCR).

RESULTS

Our results showed a significant decrease over time in cell proliferation, collagen deposition and type III/type I collagen ratio, together with an increase in MMP release, when cells were incubated in media containing sex hormones at menopausal levels. This is consistent with in vivo data from menopausal women available in the literature. Surprisingly, procollagen gene expression was only reduced within the first hours and increased afterwards when compared with non-menopausal culture conditions.

CONCLUSION

Our results demonstrated that the increased procollagen synthesis with menopausal conditions was not sufficient to compensate for the MMPs' catabolic effects and/or the impaired procollagen protein maturation, resulting in a decrease in extracellular collagen content. These findings add to the overall understanding of hormone-dependent skin behaviour and highlight the suitability of this in vitro model for cosmetic actives testing aiming to underpin claims of anti-ageing efficacy, specifically for menopausal women, regarding collagen metabolism and balance of types, for maintenance of dermal mechanical properties.

Cellular senescence: molecular mechanisms, in vivo significance, and redox considerations

Cellular senescence is recognized as a critical cellular response to prolonged rounds of replication and environmental stresses. Its defining characteristics are arrested cell-cycle progression and the development of aberrant gene expression with proinflammatory behavior. Whereas the mechanistic events associated with senescence are generally well understood at the molecular level, the impact of senescence in vivo remains to be fully determined. In addition to the role of senescence as an antitumor mechanism, this review examines cellular senescence as a factor in organismal aging and age-related diseases, with particular emphasis on aberrant gene expression and abnormal paracrine signaling. Senescence as an emerging factor in tissue remodeling, wound repair, and infection is considered. In addition, the role of oxidative stress as a major mediator of senescence and the role of NAD(P)H oxidases and changes to intracellular GSH/GSSG status are reviewed. Recent findings indicate that senescence and the behavior of senescent cells are amenable to therapeutic intervention. As the in vivo significance of senescence becomes clearer, the challenge will be to modulate the adverse effects of senescence without increasing the risks of other diseases, such as cancer. The uncoupled relation between cell-cycle arrest and the senescent phenotype suggests that this is an achievable outcome.

Functional implications of the IL-6 signaling pathway in keloid pathogenesis

The molecular mechanism(s) behind keloid pathogenesis remains unclear. Previously by global gene expression analysis of keloid fibroblasts (KFs), we implicated the IL-6 signaling pathway in keloid pathogenesis. Here, we determine a functional role of IL-6 signaling in keloid scars. Primary cultures of KFs and surrounding nonlesional fibroblasts (NFs) were subjected to induction or inhibition of IL-6 or its specific receptor IL-6 receptor alpha (IL-6R alpha) and detection of their effects on extracellular matrix gene expression. The levels of gp130 and several downstream targets in IL-6 signaling were also examined. IL-6 secretion was significantly higher in KFs than NFs. Addition of IL-6 peptide to NFs culture or inhibition of IL-6 or its receptor IL-6R alpha by their corresponding antibodies in KFs culture revealed a dose-dependent increase or decrease in collagen type I alpha 2 and fibronectin 1 mRNAs, respectively. Induction of IL-6 by IL-1beta peptide and stimulation by IL-6 peptide in NFs, or inhibition of IL-6 or IL-6R alpha in KFs cultures demonstrated a dose-dependent increase or decrease in procollagen I synthesis, respectively. The mRNA and protein expressions of gp130 and several downstream targets in IL-6 signaling (JAK1, STAT3, RAF1, and ELK1) were upregulated in KFs versus NFs. Our results indicate that IL-6 signaling may play an integral role in keloid pathogenesis and provide clues for development of IL-6 receptor blocking strategies for therapy or prophylaxis of keloid scars.

Scleroderma and pseudoscleroderma: uncommon presentations

Scleroderma is characterized by major clinical symptoms, but a number of unrelated disease may mimic these features more or less completely. Even scleroderma itself sometimes presents in an unusual manner. This article deals with uncommon presentations of true scleroderma and its variants and pseudo -scleroderma diseases.

Global Gene Expression Analysis of Keloid Fibroblasts in Response to Electron Beam Irradiation Reveals the Involvement of Interleukin-6 Pathway

Keloid is a dermal fibroproliferative lesion of unknown etiology that commonly recurs after surgical excision. Post-operative adjuvant electron beam (EB) irradiation has been successfully used to reduce keloid recurrences. To provide new insights into the molecular mechanism behind the effect of EB irradiation, we used a cDNA microarray screening of more than 5000 genes to assess early changes in gene expression between EB-irradiated and non-irradiated keloid and non-lesional dermal fibroblasts. Primary fibroblast cultures from keloid and associated non-lesional dermis obtained from five patients were exposed to 15 Gy EB irradiation and analyzed after 15 min incubation. Early response to EB irradiation showed that 96 (1.8%) genes were modulated 2-fold or more in keloid fibroblasts. Upregulated genes accounted for 29.2% (28 genes), whereas downregulated genes comprised 70.8% (68 genes), indicating a silencing of many genes in keloid fibroblasts after EB irradiation. Many of the downregulated genes play roles in the enhancement of cell proliferation and extracellular matrix production, whereas several of the upregulated genes involves in the promotion of apoptosis and extracellular matrix (ECM) degradation. Using emerging bioinformatic tools and further corroboration, the interleukin 6 (IL-6) signaling pathway was found to be mainly involved in EB irradiation response. We also showed co-expression of IL-6 and its specific receptor (IL-6Ralpha) in keloid fibroblasts that points to the existence of an IL-6 autocrine loop in these cells. These results suggested that at the molecular level, EB irradiation might hinder keloid formation by regularizing disturbances in the homeostatic equilibrium between inducer and inhibitor activities in the matrix system most likely through the IL-6 pathway. Our study provides clues for the molecular mechanism(s) behind the beneficial effect of EB irradiation in reducing keloid recurrences and may help develop alternative strategies for the therapy and prophylaxis of this lesion.

PKC412 induces apoptosis through a caspase-dependent mechanism in human keloid-derived fibroblasts

There is no established pharmacological therapy for skin keloids, a wound healing disorder. In this study, we investigated the effect of N-benzoyl staurosporine (PKC412), a protein kinase C inhibitor, on human keloid-derived fibroblasts to examine whether this agent is applicable for the treatment of keloid formation. Although PKC412 induced apoptosis in keloid fibroblasts in a time- and dose-dependent manner, the effective concentration of this agent was much higher than that of staurosporine. Western blotting showed that both PKC412 (10 microM) and staurosporine (100 nM) cleaved pro-caspase-3 to active forms. An in vitro caspase assay also showed that PKC412 and staurosporine elevated caspase-3 activities. Carbobenzoxy-Val-Ala-Asp-fluoromethyl ketone (Z-VAD-FMK), a caspase inhibitor with a broad spectrum, inhibited caspase-3 activities stimulated by PKC412 and staurosporine; however, only PKC412-induced apoptosis, but not staurosporine-induced apoptosis, was prevented by Z-VAD-FMK. These results suggested that PKC412-induced apoptosis, but not staurosporine-induced apoptosis, is mainly mediated by the caspase-dependent mechanism.

Impaired balance of type I and type III procollagen mRNA in cultured fibroblasts of patients with incisional hernia

BACKGROUND

Recent findings of an impaired protein ratio of type I to type III procollagen showed a disturbed collagen metabolism in incisional hernia development. We analyzed the type I and type III procollagen messenger RNA to investigate whether these findings represent the altered extracellular matrix or a primary defect at the transcriptional level.

METHODS

We examined cultured skin fibroblasts of patients with incisional or recurrent incisional hernia in comparison with those without any previous incision (control) and those with a skin scar without clinical appearance of a hernia (scar). Immunohistochemical detection of a lowered protein ratio of type I and type III collagen in the hernia skin tissue leads to mRNA expression analysis. The procollagen mRNA and the ratio of type I to type III procollagen mRNA are detected by reverse transcriptase-polymerase chain reaction and Northern blot analysis, the collagens type I and III by Western blot analysis.

RESULTS

Reverse transcriptase-polymerase chain reaction revealed an increase of type I procollagen mRNA in the incisional and recurrent hernia (0.90 +/- 0.04 and 1.19 +/- 0.04, respectively) compared with stable scar (0.54 +/- 0.02) or healthy tissue (0.43 +/- 0.01). The obvious rise of type III procollagen mRNA to 4.13 +/- 0.04 for incisional, 6.02 +/- 0.03 for recurrent hernia, 2.29 +/- 0.04 for stable scar, and 1.72 +/- 0.03 for the healthy tissue showed a significantly decreased ratio of type I to type III procollagen mRNA in the hernia patients as compared with the controls (P <.01). By Western blot analysis, an increase of type I and type III collagen protein and a significant rise in the corresponding ratio in the recurrent hernia group were detected.

CONCLUSIONS

The altered synthesis of type I and type III collagen in cultured skin fibroblasts suggests a disorder of collagen metabolism, at least in patients with recurrent hernia. Hence, a basically impaired wound healing process is likely to contribute to the unsatisfactory results of incisional hernia repair.

Keloid fibroblasts resist ceramide-induced apoptosis by overexpression of insulin-like growth factor I receptor

Keloids are benign dermal tumors, characterized by overgrowth of lesions, invasiveness beyond the original boundary of the insult, and recurrence of lesions. The exact etiology is unknown, however. Our hypothesis is that keloids are acquired as a result of an abnormal or prolonged wound healing process, with persistent proliferation and extracellular matrix production of fibroblasts that should otherwise discontinue in normal wound healing. In this study, we examined the response of keloid fibroblasts to proapoptotic signaling. Cell-permeable ceramide, N-acetyl-D-sphingosine, induced apoptosis of dermal fibroblasts in a dose- and time-dependent manner, which was detected by phase contrast microscopy, fluorescent microscopy, the TUNEL method, flow cytometric analysis, and WST-1 assay. In contrast, keloid fibroblasts resisted apoptosis induced by N-acetyl-D-sphingosine (percent survival with 40 mM ceramide treatment for 12 h, normal versus keloid: 9.6% +/- 6.6% vs 66.8% +/- 5.5%). Western blotting analysis showed insulin-like growth factor I receptor overexpression in keloid fibroblasts, but not in normal fibroblasts. Exogenously added insulin-like growth factor I enhanced the resistance of keloid fibroblasts to ceramide-induced apoptosis. Wort- mannin, a phosphatidylinositol 3 kinase inhibitor, suppressed the antiapoptotic action of insulin-like growth factor I in keloid fibroblasts. Our results suggest that keloid fibroblasts overexpressing insulin-like growth factor I receptor are resistant to apoptosis, thus allowing persistent proliferation and production of excessive extracellular matrix. J Invest Dermatol 115:1065-1071 2000

Overexpression of insulin-like growth factor-1 (IGF-I) receptor and the invasiveness of cultured keloid fibroblasts

Keloid is a dermal fibroproliferative tissue of unknown etiology. Protein tyrosine kinases (PTKs) play an important role in the regulation of cell growth and differentiation. Activation of PTK cascades in keloid fibroblasts is thought to be closely linked to abnormal cell proliferation and migration. We determined the expression profile of PTK genes in normal skin and keloid fibroblasts using the homology cloning method with a degenerated primer. Eight PTK genes were expressed among a total of 46 receptor-type clones. The most abundant type of PTK receptors was the platelet-derived growth factor receptor in both fibroblasts. However, insulin-like growth factor-I receptor (IGF-IR) was overexpressed only in keloid-derived fibroblasts (9 of 24). Immunohistochemical analysis confirmed the high expression of IGF-IR in keloid fibroblasts, but not in normal fibroblasts. To examine the functional properties of the IGF-I/IGF-IR pathway, we investigated cell proliferation and invasion activities of both types of fibroblasts. The mitogenic effect of IGF-I on both fibroblasts was very weak compared with serum stimulation. In contrast, the invasive activity of keloid fibroblasts was markedly increased in the presence of IGF-I, and inhibited by a neutralizing antibody against IGF-IR. Our results indicate the involvement of activated IGF-I/IGF-IR in the pathogenesis of keloid by enhancing the invasive activity of fibroblasts.

Accelerated linear growth and advanced bone age in Sotos syndrome is not associated with abnormalities of collagen metabolism

OBJECTIVES

To investigate whether the advanced bone age in Sotos syndrome is associated with alterations in type I collagen metabolism in bone.

DESIGN AND METHODS

The metabolism of collagen was studied by analyzing the production, gene expression and degradation of type I collagen in dermal fibroblast strains from patients with Sotos syndrome and comparing them with fibroblasts from age-matched healthy subjects. Collagen production was determined as collagenase digestible radioactivity and collagen mRNA levels were measured by RT-PCR. Collagen degradation was assessed by specific collagenase assay and gelatin zymography. To determine the structural defects in type I collagen, the newly synthesized proteins were analyzed by SDS-PAGE before and after proteolytic digestion with pepsin.

RESULTS

In the present study, we have demonstrated that the collagen production, secretion and degradation in Sotos syndrome is comparable to controls. In addition, no qualitative differences in mRNA transcripts for type I collagen were detected between the control and Sotos syndrome fibroblasts. The secretion and intracellular accumulation of procollagen is also comparable to controls. The analysis of both procollagen and collagen on SDS-PAGE did not exhibit any major structural changes as compared with controls.

CONCLUSIONS

Our results on several aspects of collagen metabolism have demonstrated for the first time that collagen, the most abundant of mammalian proteins and the major constituent of bone, is normal in patients with Sotos syndrome. Therefore, it appears that the advanced bone age and accelerated linear growth seen in patients with Sotos syndrome may not be attributed to inherent abnormalities of collagen metabolism. The etiology and the pathogenesis of Sotos syndrome still remains unclear.

Regulation of matrix metalloproteinase (MMP) expression in cutis laxa fibroblasts: upregulation of MMP-1, MMP-3 and MMP-9 genes but not of the MMP-2 gene

A major histopathological abnormality in cutis laxa (CL) is a paucity of elastic structures. The aim of this study was to investigate the gene expression levels of the major matrix degrading factors matrix metalloproteinase (MMP) 1, MMP-2, MMP-3 and MMP-9 in CL. The gene expression levels of MMP-1, MMP-2, MMP-3 and MMP-9 in cultured CL fibroblasts were measured by northern blot, immunoblot and gelatin zymographic analysis. Markedly increased mRNA levels of MMP-1 (8.4-fold), MMP-3 (7.2-fold) and MMP-9 (more than 10-fold) were found in CL fibroblasts, whereas MMP-2 mRNA levels in these fibroblasts were unaltered. Increased protein production levels of MMP-1 (4.6-fold) and MMP-3 (5.1-fold) in CL fibroblasts were shown by immunoblot analysis. On gelatin zymographic analysis, the gelatinolytic activities of MMP-9 but not of MMP-2 were increased (2.2-fold). These results suggest that increased gene expression levels of MMP-1, MMP-3 and MMP-9 in CL fibroblasts may contribute to the histopathological abnormality in CL.

Scleroderma-like disorders

Scleroderma-like disorders are widely disparate conditions mimicking either systemic sclerosis or cutaneous localized scleroderma, not infrequently displaying features of both. Some are exclusively sclerotic, some scleroatrophic with prevailing sclerosis or atrophies. The recognition of scleroderma-like disorders is of practical importance because by establishing the cause of the disease, it is possible to introduce an effective therapy, as in scleredema Buschke or scleredema diabeticorum, sclerodermiform porphyria, Borrelia burgdorferi-induced sclerodermiform acrodermatitis atrophicans, sclerodermiform phenylketonuria, drug-induced conditions, and so on. Scleroderma-like disorders strongly suggest that the pathogenesis of skin sclerosis and internal involvement may be divergent, and of various causes. Some of them, such as atrophoderma Pasini-Pierini or progressive facial hemiatrophy, frequently overlapping with scleroderma, make the differentiation very difficult, if at all possible, and the diagnosis is often arbitrary. Some, as sclerodermiform graft-versus-host reaction, point to the autoimmune origin of scleroderma. The amply-covered congenital sclerodermiform conditions present a large spectrum of still not widely known and extremely heterogeneous syndromes, associated with numerous anomalies and/or malignancies.

Effects of in vitro cellular aging on alkaline phosphatase, cathepsin activities and collagen secretion of human periodontal ligament derived cells

It is believed that the degree of periodontal tissue breakdown and tooth loss increase with age. In periodontal tissues which are gingiva, periodontal ligament (PL), alveolar bone and tooth cementum, the PL which is soft connective tissue, lies between the tooth cementum and alveolar bone, having the primary function of tooth support, and maintaining the homeostasis of supporting tissues, as well as providing the healing process. We therefore investigated the effects of in vitro cellular aging on alkaline phosphatase (ALP), cathepsin activities and collagen secretion from human PL cells obtained from 18-23 year-old patients' teeth. ALP, cathepsin activities and collagen secretion may play important roles in the remodeling and maintaining of periodontal tissues. To investigate the life span of PL cells, the cells were sequentially subcultivated. The maximum population doubling level of the PL cells in the present experiment was 22-25 passages. Investigating some important biological activities of the PL cells at different passage levels (6-7, 30% of life span to 17-20, 75% of life span), ALP activity and collagen secretion were found to have significantly decreased while cathepsin B and L activities significantly increased with cellular aging. Since these biological activities in human PL cells tend to be more catabolic with increase in cellular aging, the increase in periodontal breakdown with age may be partly related to the catabolic changes of the PL cells themselves.

The transcription of human alpha 1(I) procollagen gene (COL1A1) is suppressed by tumour necrosis factor-alpha through proximal short promoter elements: evidence for suppression mechanisms mediated by two nuclear-factorbinding sites

Recent studies have demonstrated that tumour necrosis factor-alpha (TNF-alpha) decreases alpha 1(I) procollagen gene (COL1A1) expression in cultured human dermal fibroblasts. The purpose of this study was to analyse the transcriptional control of COL1A1 by TNF-alpha. Cultured human dermal fibroblasts were transiently transfected with plasmids containing 5' flanking sequences of COL1A1 fused to the chloramphenicol acetyltransferase (CAT) gene, and were incubated for 48 h in medium with or without TNF-alpha. TNF-alpha inhibited the CAT activity of fibroblasts transfected with plasmids containing 2.3 kb of 5' flanking sequences of COL1A1, whereas the activity of control plasmids containing the herpes simplex thymidine kinase promoter gene (pBLCAT) was unaltered. A series of deletion constructs of various small substitution mutations of the COL1A1 5' flanking region fused to the CAT gene were also transfected, and CAT activity was measured after incubation with TNF-alpha. TNF-alpha suppressed COL1A1 promoter activity through proximal short promoter elements containing only 107 bp. Short substitution mutations between -101 and -97 bp or between -46 and -38 bp abolished TNF-alpha suppression of COL1A1 promoter activity. DNA-protein complex formation was observed involving both sites in gel retardation assays. These results suggest that TNF-alpha suppressed COL1A1 promoter activity through elements located between -101 and -97 bp and between -46 and -38 bp of the COL1A1 promoter, and that the suppression involved DNA-protein interactions.

Collagenase gene expression in cutis laxa fibroblasts is upregulated by transcriptional activation of the promoter gene through a 12-0-tetradecanoyl-phorbol-13-acetate (TPA)-responsive element

Our previous work demonstrated that collagenase mRNA levels are increased in fibroblasts derived from patients with cutis laxa (CL). To pursue the mechanism of the upregulation of collagenase expression, we investigated transcriptional levels of the collagenase gene in CL fibroblasts. Fibroblasts cultured from the skin of three congenital CL patients were studied. Northern blot hybridization revealed 2.8- to 7.3-fold increases in collagenase mRNA levels in CL fibroblasts compared with normal cells. Nuclear run-off experiments demonstrated that the transcription rate of the collagenase gene in nuclei isolated from the same cells was 5.1- to 10.2-fold higher in the CL fibroblasts than in the controls. Transient transfection of a normal collagenase promoter-CAT construct into the cells further showed significantly enhanced transcriptional activity in CL but not in normal fibroblasts. Experiments of transient transfection of deleted or small substituted collagenase promoter-CAT constructs indicated that collagenase transcription in CL fibroblasts was activated the TPA-responsive element site of the collagenase promoter gene. Although the levels of Jun and Fos gene expression did not differ from those observed in normal fibroblasts, AP-1-binding activity, as measured by the ability to bind to an oligonucleotide containing a TPA-responsive element, was significantly elevated in CL fibroblasts as compared with normal fibroblasts. These data suggest that collagenase expression is upregulated at the transcriptional level by endogenous activation of DNA binding of AP-1 in CL fibroblasts [corrected].

Effects of tretinoin tocoferil on gene expression of the extracellular matrix components in human dermal fibroblasts in vitro

Recently, it has been reported that tretinoin tocoferil (TT), a synthesized ester-bond compound of all-trans-retinoic acid and alpha-tocopherol, accelerates the formation of granuloma and is effective in promoting experimental open skin wound healing. To investigate whether TT affects the gene expression of extracellular matrix components of human dermal fibroblasts, we measured the mRNA levels of various extracellular matrix components of fibroblasts incubated with TT using specific cDNA probes. The mRNA levels of elastin increased up to 30% of the controls and those of collagen III and VI up to 60%. The mRNA levels of collagen I and fibronectin remarkably increased up to 90% of the controls. These results suggest that the stimulatory effect of TT on the gene expression of many extracellular matrix components might be one of the mechanisms of its promotion of wound healing.

Decreased collagenase expression in cultured systemic sclerosis fibroblasts

One cause of the excessive deposition of collagen in systemic sclerosis is thought to be abnormal functioning of fibroblasts. The purpose of this study is to determine whether there is decreased expression of collagenase in systemic sclerosis fibroblasts. In this study, we analyzed collagen and collagenase expression in dermal fibroblasts derived from eight patients with systemic sclerosis and compared the findings with those from nine sex- and age-matched healthy subjects. Increased collagen synthesis accompanying enhanced mRNA levels was observed in two of eight strains, whereas all eight strains showed remarkable decreases in collagenase activity and production. There were no differences in the levels of collagenase mRNA between the systemic sclerosis strains and the normal strains. Results suggest that decreased collagenase expression is a characteristic of systemic sclerosis fibroblasts, and both increased collagen expression and decreased collagenase expression in systemic sclerosis fibroblasts may result in the excessive accumulation of collagen in patients with systemic sclerosis. It is also suggested that decreased collagenase expression is altered at translational and/or post-translational levels.

Activation of fibroblast proliferation by Werner's syndrome fibroblast-conditioned medium

The effects of Werner's syndrome (WS) fibroblast-conditioned medium on cell proliferation and collagen production of normal fibroblasts were studied using four WS fibroblast strains. The conditioned medium from the WS fibroblasts brought about activation of normal fibroblast proliferation, whereas, that from late passage normal fibroblasts and fibroblasts from aged donors' skin did not. Collagen and non-collagenous protein synthesis in normal fibroblasts were increased by the addition of conditioned medium from the WS fibroblasts, but the relative rates of collagen synthesis and non-collagenous protein synthesis were unaltered. These results suggest that activation of fibroblast proliferation by conditioned medium is one of the characteristics of WS fibroblasts.

Decreased type VI collagen gene expression in cultured Werner's syndrome fibroblasts

Gene expression of collagens VI, I, and III in Werner's syndrome was studied by measuring messenger RNA (mRNA) and protein production levels in four fibroblast strains from patients with Werner's syndrome and comparing them with age-matched healthy subjects. Levels of type VI collagen mRNA were decreased in all Werner's syndrome fibroblast strains and the decreases were in parallel in all three chains (alpha 1, alpha 2, and alpha 3) of type VI collagen. A coordinate increase of the alpha 1(I) and alpha 1(III) collagen mRNA levels was observed in three of the four Werner's syndrome fibroblast strains. However, no qualitative abnormality of these mRNA transcripts in Werner's syndrome fibroblasts were found by Northern blot analysis. Changes in type VI and type I collagen mRNA correlated well with production levels of corresponding proteins, as determined by immunologic assays. These data suggest that there are changes in expression of multiple connective tissue constituents in Werner's syndrome fibroblasts.

Effects of tumor necrosis factor-alpha on connective tissue metabolism in normal and scleroderma fibroblast cultures

Recent studies have demonstrated that tumor necrosis factor-alpha (TNF-alpha) selectively decreases production of collagens I and III, the major types of collagen in the dermis, and increases production of collagenase in cultured dermal fibroblasts. The effects of TNF-alpha on collagens I, III and VI, fibronectin and collagenase gene expression by fibroblasts derived from normal individuals and patients with systemic sclerosis (SSc) were studied. SSc is characterized by excessive accumulation of collagen in the skin and in certain organs. TNF-alpha inhibited collagen production and mRNA levels of collagens I and III and of fibronectin, and stimulated collagenase activity and collagenase mRNA levels in SSs fibroblasts. Levels of mRNA for alpha 1 (VI) and alpha 3 (VI) collagen and for beta-actin were unaltered in SSc fibroblasts incubated with TNF-alpha. Similar results were observed for mRNA levels in normal fibroblasts incubated with TNF-alpha. These results suggest that TNF-alpha could be expected to be beneficial in the treatment of SSc. In addition, our results indicated that collagen-VI expression is regulated independently from expression of collagens I and III, and expression of fibronectin and collagens I and III are regulated in parallel in fibroblasts treated with TNF-alpha.

Similar, but not identical, modulation of expression of extracellular matrix components during in vitro and in vivo aging of human skin fibroblasts

Regulation of the synthesis of procollagen and other extracellular matrix components was examined in human skin fibroblasts obtained from donors of various ages, from fetal to 80 years old (in vivo aged), and in fetal fibroblasts at varying passage levels (in vitro aged). Growth rates and saturation densities of fibroblasts decreased with increasing age of the donor and after passage 20 of fetal fibroblasts. The rates of collagen and proteoglycan synthesis also decreased during both types of aging to about 10-25% of the rate in early passage fetal fibroblasts, whereas the synthesis of total noncollagenous proteins was not greatly affected. Decreased collagen synthesis in both types of aging was correlated with lower steady-state levels of mRNAs for the two subunits of type I procollagen mRNA, although their regulation was not coordinate. Type III collagen mRNA levels also declined in both types of aging. The concentration of fibronectin mRNA also decreased during in vitro aging but more rapidly than the collagen mRNAs, whereas in fibroblasts from 51-80-year-old donors, it was similar to or higher than in early passage fetal fibroblasts. This study suggests that the decreased synthesis of procollagen and proteoglycans in in vivo aged fibroblasts represents changes that are responsible for intrinsic degenerative changes that occur in human skin during aging. Furthermore, although in vitro and in vivo aging were similar in many respects, they were not equivalent, as evidenced by the differences in regulation of fibronectin expression.

New variant of cytochrome b5 reductase deficiency (b5RKurashiki) in red cells, platelets, lymphocytes, and cultured fibroblasts with congenital methemoglobinemia, mental and neurological retardation, and skeletal anomalies

A Japanese man with cytochrome b5 reductase (b5R) deficiency in various blood cell lineages (red cells, platelets, and lymphocytes) and in cultured fibroblasts demonstrated congenital methemoglobinemia associated with mental and neurological retardation, and various skeletal anomalies, such as spondylosis deformans and finger joint deformations, which have never been described in association with this enzyme deficiency. Cytochrome b5 reductase deficiency was most severe in red cells (0.3-4%) and less marked in platelets (13-27%), lymphocytes (18-31%), and fibroblasts (50%). The present case appears to be a new variant of cytochrome b5 reductase deficiency (b5RKurashiki).

Insulin resistance in Werner's syndrome

Insulin resistance in Werner's syndrome (WS) was studied using the glucose clamp technique, and compared with physiologically aged and young subjects. Fasting immuno-reactive insulin (IRI) was increased in patients with Werner's syndrome compared with aged and young subjects. Metabolic clearance rate (MCR) of glucose was decreased in the aged and WS. A rightward shift of the dose-response curves of insulin and MCR of glucose was observed in the aged and WS with a more pronounced shift in the latter. MCR of insulin was also decreased in WS. [125I]insulin binding to erythrocytes was similar in the three groups. These results suggest that insulin resistance associated with WS is due to a post-binding defect manifested by a rightward shift of the dose-response curve of insulin-induced glucose disposal and a decrease in insulin clearance rate.

Cellular localization of procollagen gene transcripts in inflammatory bowel diseases

The cellular localization of procollagen types I, III, IV, and V gene transcripts was determined in tissues from 12 patients with either Crohn's disease (CD) or ulcerative colitis (UC) and nine controls by in situ hybridization with 35S-labeled RNA probes. In CD, the signal intensity and number of labeled cells were significantly increased, particularly in deeper intestinal layers. In contrast, the labeled cells in UC were concentrated in the subepithelial intestinal layers, with an overexpression of procollagen III RNA transcripts. Immunohistological stainings for procollagen types I, III, and IV showed a weaker staining in UC than in CD, indicating that increased transcript levels in UC are unrelated to the enhanced collagen protein deposition, although the increase of procollagen messenger RNA levels correlated with the density of the inflammatory infiltrate. It was concluded that both CD and UC show highly increased procollagen RNA transcript levels but differ in collagen deposition. Thus, different posttranscriptional or posttranslational regulatory mechanisms, such as collagen degradation, may account for the observed differences.

Collagen metabolism in cutis laxa fibroblasts: increased collagenase gene expression associated with unaltered expression of type I and type III collagen

Collagen metabolism was studied in cutis laxa by analyzing collagen and collagenase gene expression in three dermal fibroblast strains from patients with congenital cutis laxa and comparing them with fibroblasts obtained from age-matched healthy subjects. Normal collagen synthetic activity was observed in the cutis laxa fibroblasts. An increased level of collagenase mRNA and unaltered levels of alpha 1(I) and alpha 1(III) collagen mRNA were found in all cutis laxa cell strains by dot blot hybridization. Reduced levels of elastin mRNA were also detected in these strains. However, no qualitative differences in these mRNA transcripts were detected between the control and cutis laxa fibroblasts by Northern blot analysis. Collagenase activity in fibroblast culture supernatants was then measured using fluorescein isothiocyanate (FITC)-labeled type I collagen. Increased collagenolytic activity in cutis laxa fibroblast culture supernatants was also found. These data suggest that increased collagenase expression of fibroblasts is related to the structural abnormality of dermal connective tissue in cutis laxa.

Diverse gene sequences are overexpressed in werner syndrome fibroblasts undergoing premature replicative senescence

Genes that play a role in the senescent arrest of cellular replication are likely to be overexpressed in human diploid fibroblasts (HDF) derived from subjects with Werner syndrome (WS) because these cells have a severely curtailed replicative life span. To identify some of these genes, a cDNA library was constructed from WS HDF after they had been serum depleted and repleted (5 days in medium containing 1% serum followed by 24 h in medium containing 20% serum). Differential screening of 7,500 colonies revealed 102 clones that hybridized preferentially with [32P]cDNA derived from RNA of WS cells compared with [32P]cDNA derived from normal HDF. Cross-hybridization and partial DNA sequence determination identified 18 independent gene sequences, 9 of them known and 9 unknown. The known genes included alpha 1(I) procollagen, alpha 2(I) procollagen, fibronectin, ferritin heavy chain, insulinlike growth factor-binding protein-3 (IGFBP-3), osteonectin, human tissue plasminogen activator inhibitor type I, thrombospondin, and alpha B-crystallin. The nine unknown clones included two novel gene sequences and seven additional sequences that contained both novel segments and the Alu class of repetitive short interspersed nuclear elements; five of these seven Alu+ clones also contained the long interpersed nuclear element I (KpnI) family of repetitive elements. Northern (RNA) analysis, using the 18 sequences as probes, showed higher levels of these mRNAs in WS HDF than in normal HDF. Five selected mRNAs studied in greater detail [alpha 1(I) procollagen, fibronectin, insulinlike growth factor-binding protein-3, WS3-10, and WS9-14] showed higher mRNA levels in both WS and late-passage normal HDF than in early-passage normal HDF at various intervals following serum depletion/repletion and after subculture and growth from sparse to high-density confluent arrest. These results indicate that senescence of both WS and normal HDF is accompanied by overexpression of similar sets of diverse genes which may play a role in the senescent arrest of cellular replication and in the genesis of WS, normal biological aging, and attendant diseases.

Diverse gene sequences are overexpressed in werner syndrome fibroblasts undergoing premature replicative senescence

Genes that play a role in the senescent arrest of cellular replication are likely to be overexpressed in human diploid fibroblasts (HDF) derived from subjects with Werner syndrome (WS) because these cells have a severely curtailed replicative life span. To identify some of these genes, a cDNA library was constructed from WS HDF after they had been serum depleted and repleted (5 days in medium containing 1% serum followed by 24 h in medium containing 20% serum). Differential screening of 7,500 colonies revealed 102 clones that hybridized preferentially with [32P]cDNA derived from RNA of WS cells compared with [32P]cDNA derived from normal HDF. Cross-hybridization and partial DNA sequence determination identified 18 independent gene sequences, 9 of them known and 9 unknown. The known genes included alpha 1(I) procollagen, alpha 2(I) procollagen, fibronectin, ferritin heavy chain, insulinlike growth factor-binding protein-3 (IGFBP-3), osteonectin, human tissue plasminogen activator inhibitor type I, thrombospondin, and alpha B-crystallin. The nine unknown clones included two novel gene sequences and seven additional sequences that contained both novel segments and the Alu class of repetitive short interspersed nuclear elements; five of these seven Alu+ clones also contained the long interpersed nuclear element I (KpnI) family of repetitive elements. Northern (RNA) analysis, using the 18 sequences as probes, showed higher levels of these mRNAs in WS HDF than in normal HDF. Five selected mRNAs studied in greater detail [alpha 1(I) procollagen, fibronectin, insulinlike growth factor-binding protein-3, WS3-10, and WS9-14] showed higher mRNA levels in both WS and late-passage normal HDF than in early-passage normal HDF at various intervals following serum depletion/repletion and after subculture and growth from sparse to high-density confluent arrest. These results indicate that senescence of both WS and normal HDF is accompanied by overexpression of similar sets of diverse genes which may play a role in the senescent arrest of cellular replication and in the genesis of WS, normal biological aging, and attendant diseases.

Cellular ageing related proteins secreted by human fibroblasts

Fibroblast secreted proteins participate in the formation of extracellular matrix. Extracellular matrix affects growth factor action, mediates cell adhesion and supports cell growth. Structural and quantitative characteristics of secreted proteins are modified in a similar manner, during both in vivo and in vitro cellular ageing. Such ageing related modifications may either be directly controlled by primary ageing causes, or evolve from a reformation of the extracellular matrix induced by a few ageing defects in key proteins such as fibronectin. They may result in the further inhibition of cell adhesion, cell stimulation by growth factors and, eventually, of cell proliferative ability.