Search

Matrix metalloproteinase (MMP)-21 and MMP-26 (matrilysin-2) are two recently cloned epithelial metalloproteases. Here we examined their expression in various benign skin disorders, in which macrophages and fibroblasts have been implicated as well as in cultures of these cells. Expression of MMP-21 was detected by immunohistochemistry in a subset of macrophages of granulomatous skin lesions and in fibroblasts in dermatofibromas. MMP-21 mRNA was found in THP-1, U937, HEL 299 and Hs68 cells. Furthermore, MMP-21 protein was detected by immunohistochemistry in cultures of the same cell lines. In culture MMP-21 was upregulated by phorbol myristate acetate in THP-1 cells and by retinoic acid (RA) in U937 cells, and downregulated by transforming growth factor beta 1 (TGF-beta1) in HEL 299 as assessed by Taqman quantitative polymerase chain reaction (PCR). Expression of MMP-26 was detected by immunohistochemistry in granulomatous skin diseases and actinic elastosis. MMP-26 at both mRNA and protein levels was only found in HEL 299 cells. In culture it was downregulated by TGF-beta1, RA and IL-1beta as assessed by Taqman quantitative PCR. Our results suggest these two novel MMPs are not only associated with cancer but may be important in connective tissue remodelling and pathobiology of various benign skin disorders.

Human metalloelastase (MMP-12) has been implicated in elastin degradation and macrophage migration in many pathological conditions. It also generates angiostatin, thus having a potential to prevent tumour angiogenesis. It has previously been shown that transformed epithelial cells express MMP-12 in skin cancer. The aim of this study was further to elucidate the role of metalloelastase in squamous cell cancer (SCC) progression. By in situ hybridization, expression of MMP-12 mRNA was detected in 28/33 vulvar SCC samples in CD-68-positive macrophages, while 10 samples had positive cancer cells. By immunohistochemistry, MMP-12 protein was seen in the same area as the mRNA. MMP-12 mRNA expression in tumour cells correlated with more aggressive histology (p = 0.0099). In contrast, macrophage-derived MMP-12 mRNA was more abundant in well-differentiated grade I than grade III tumours (p = 0.01). However, the level of MMP-12 mRNA, regardless of its origin, did not correlate with metastasis or patient survival. No significant correlation was found between macrophage-derived MMP-12 mRNA and a low amount of blood vessels, as quantitated after von Willebrand staining. In agreement with vulvar SCCs in vivo, MMP-12 was expressed in cultured SCC cells by northern and western blot analysis. In HaCaTs and epithelial MCF-10f cells, MMP-12 mRNA was induced by transforming growth factor-beta1 (TGF-beta1) and tumour necrosis factor-alpha (TNF-alpha) as measured by quantitative RT-PCR (TaqMan). Two MMPs capable of generating angiostatin in vivo, matrilysin (MMP-7) and gelatinase B (MMP-9), were also examined in these tumours. MMP-7 mRNA was mainly expressed by epithelial tumour cells, particularly in less differentiated tumours. MMP-9 was usually expressed by neutrophils and macrophages; epithelial protein was predominantly found in grade II/III tumours. These results suggest a dual role for MMP-12 in tumour progression., (Copyright 2002 John Wiley & Sons, Ltd.)

Allograft inflammatory factor-1 (AIF-1) is an evolutionarily conserved, inflammatory protein produced by activated macrophages during chronic transplant rejection and in inflammatory brain lesions. Since T-cell-mediated inflammation is common to various dermatoses and nothing is known about AIF-1 in skin, we studied its protein expression at the tissue level and regulation in monocytic cell lines by various agents. Using immunohistochemistry, we found that ALF-1 is expressed at low levels in normal skin, but is highly upregulated in various inflammatory skin disorders, such as psoriasis, lichen planus, graft- versus-host disease and mycosis fungoides. The main cell types expressing AIF-1 in affected skin are macrophages and Langerhans' cells. We also show by real-time PCR that AIF-1 mRNA levels in monocytic THP-1 and U937 cell lines are significantly upregulated by retinoic acid as well as a number of cytokines. We conclude that AIF-1 may mediate survival and pro-inflammatory properties of macrophages in skin diseases. [ABSTRACT FROM AUTHOR]

Keratinocyte hyperproliferation, inflammatory infiltrates, neoangiogenesis and alterations in cytokine levels are hallmarks of psoriatic skin. Matrix metalloproteinases (MMPs) have been associated with the remodeling of the extracellular matrix during inflammation, neovascularization, and malignant transformation. We have previously shown that particularly MMP-12 is abundantly expressed by macrophages and MMP-9 in macrophages and neutrophils of psoriatic lesions. In this work the expression of two novel metalloproteinases, MMP-19 and MMP-28, was investigated in psoriatic lesional and nonlesional skin. MMP-19 protein was detected by immunohistochemistry in 28/29 samples in keratinocytes in the same regions as Ki67 (marker of proliferating keratinocytes) and p63 (marker of keratinocyte stem cells). Immunosignaling was also seen in endothelial cells and fibroblasts. Furthermore, MMP-19 mRNA was upregulated in psoriatic keratinocytes and skin as assessed by quantitative real-time polymerase chain reaction. In lichen planus and lichenoid chronic dermatitis, MMP-19 staining was found in keratinocytes in areas where the basement membrane was abnormal. MMP-28 was not detected in psoriatic or nonlesional skin. Our results suggest that keratinocytes as well as the previously reported cell types (smooth muscle, endothelial and macrophages) can express MMP-19 in psoriasis and lichen planus. Upregulation of MMP-19 in keratinocytes may be influenced by changes in the architecture of the basement membrane zone. [ABSTRACT FROM AUTHOR]

Photodamage is characterized by degradation of collagen and accumulation of abnormal elastin in the superficial dermis and several matrix metalloproteinases have previously been implicated in this process. Using immunohistochemistry and in situ hybridization, we have studied the localization of two elastolytic matrix metalloproteinases, matrilysin (matrix metalloproteinase-7) and human macrophage metalloelastase (matrix metalloproteinase-12) in solar damage. Human macrophage metalloelastase protein was detected in the superficial dermis in areas of elastotic material. Matrix metalloproteinase-7 was seen in the mid-dermis in regions with less damaged elastic fibers and morphologically better preserved collagen as well as in a band-like pattern below basal keratinocytes in eight of 18 solar elastosis. In samples taken from healthy volunteers 3 d after repeated ultraviolet A or ultraviolet B photoprovocation, occasional immunopositive cells for human macrophage metalloelastase (stromal) or matrix metalloproteinase-7 (sweat gland epithelium) were detected. In samples taken 1 d after ultraviolet B exposure, however, basal keratinocytes were matrix metalloproteinase-7 immunopositive, explaining the linear immunostaining below basal keratinocytes noted particularly in ultraviolet B treated 3 d specimens. Upregulation of metalloelastase was also demonstrated in the skin of hairless mice after repeated ultraviolet exposure. In normal skin, no staining for human macrophage metalloelastase or matrix metalloproteinase-7 was observed in association with elastin. The amount of immunoreactivity for the substrates of matrix metalloproteinase-7, versican, and tenascin, was clearly increased in solar elastosis and photoprovocated skin; versican but not tenascin was detected in the same areas as matrix metalloproteinase-7. Our results suggest that both matrix metalloproteinase-7 and -12 may contribute to remodeling of elastotic areas in sun-damaged skin. [ABSTRACT FROM AUTHOR]

Matrix metalloproteinases (MMPs) are a family of zinc-dependent endopeptidases collectively capable of degrading essentially all extracellular matrix components. These enzymes can be produced by several different types of cells in skin such as fibroblasts, keratinocytes, macrophages, endothelial cells, mast cells, and eosinophils and their activity can be specifically inhibited by TIMPs (tissue inhibitors of metalloproteinases), which bind to active MMPs with 1:1 stoichiometry. In general, MMPs are not constitutively expressed in skin but are induced temporarily in response to exogenous signals such as various cytokines, growth factors, cell-matrix interactions and altered cell-cell contacts. At present, more evidence is accumulating that MMPs play an important role in proteolytic remodeling of extracellular matrix in various physiologic situations, including developmental tissue morphogenesis, tissue repair, and angiogenesis. On the other hand, MMPs play an important pathogenetic role in excessive breakdown of connective tissue components, e.g. in rheumatoid arthritis, osteoarthritis, chronic ulcers, dermal photoageing, and periodontitis, as well as in tumor cell invasion and metastasis. In this review we discuss the role of MMPs and TIMPs in human skin based on new observations on the regulation of the expression of MMPs, on their substrate specificity, and MMP expression in physiologic and pathologic conditions of skin involving matrix remodeling. Furthermore, therapeutic modalities based on regulating MMP activity will be reviewed. [ABSTRACT FROM AUTHOR]

SummaryMatrix metalloproteinases play an essential role in tumor growth and invasion. Different matrix metalloproteinases are often expressed in cancers with distinct patterns. To investigate the role of human macrophage metalloelastase (MMP-12) in epidermal tumors, we studied human macrophage metalloelastase mRNA and protein expression in malignant squamous cell and basal cell carcinomas, and in premalignant Bowen's disease. Human macrophage metalloelastase was detected in 11 of 17 squamous cell carcinomas in epithelial cancer cells, whereas macrophages were positive in 15 of 17 samples. In basal cell carcinomas, human macrophage metalloelastase was more often found in macrophages (seven of 19) than in cancer cells (four of 19). Human macrophage metalloelastase mRNA was also detected in three cell lines derived from squamous cell carcinomas of the head and neck and in transformed HaCaT cells, whereas premalignant tumors and primary keratinocytes were negative for human macrophage metalloelastase mRNA. Western analysis revealed human macrophage metalloelastase protein in squamous cell carcinoma cells. Our results show that human macrophage metalloelastase can be expressed in vivo and in vitro by transformed epithelial cells and indicate that the level of human macrophage metalloelastase expression correlates with epithelial dedifferentiation and histologic aggressiveness. [ABSTRACT FROM AUTHOR]

Accumulation of inflammatory cells such as macrophages may lead to degeneration of connective tissue matrix in various skin diseases. Macrophage metalloelastase, is a matrix metalloproteinase (MMP-12) capable of degrading elastin as well as various basement membrane components. To investigate the role of human macrophage metalloelastase in skin, we assessed by in situ hybridization and immunohistochemistry 66 specimens representing skin diseases characterized either by changes in elastic fibers or by pronounced infiltrations of extravasating and migrating macrophages. CD68 immunostaining was performed to identify the human macrophage metalloelastase-positive cells and Weigert’s Resorcin-Fuchsin staining to reveal the status of elastic fibers. We found abundant expression of human macrophage metalloelastase mRNA in macrophages in areas devoid of normal elastic fibers in granulomatous skin diseases sarcoidosis, necrobiosis lipoidica diabeticorum, and granuloma annulare. Positive cells for human macrophage metalloelastase protein could be detected in the same regions as well as positive immunostaining for urokinase plasminogen activator. Of the other matrix metalloproteinases capable of degrading elastin, 92 kDa gelatinase colocalized with human macrophage metalloelastase, while 72 kDa gelatinase was produced by surrounding fibroblast-like cells. Furthermore, human macrophage metalloelastase was expressed by macrophages in areas with disrupted basement membrane, as assessed by type IV collagen staining, in pityriasis lichenoides and dermatitis herpetiformis. Specimens of anetoderma, acrodermatitis chronica atrophicans and pseudoxanthoma elasticum showed no signal for human macrophage metalloelastase. Matrilysin was not detected in any of the samples investigated. Our study suggests that human macrophage metalloelastase may contribute to elastin degradation occurring in granulomatous skin diseases and may aid macrophage migration through the epidermal and... [ABSTRACT FROM AUTHOR]