Effects of inhaled corticosteroids on metalloproteinase-8 and tissue inhibitor of metalloproteinase-1 in the airways of asthmatic children.

BACKGROUND: The effects of corticosteroids on the level and expression of matrix metalloproteinase-8 (MMP-8; collagenase-2) and tissue inhibitors of metalloproteinases (TIMPs) in airway tissue are poorly characterized in vivo. METHODS: We compared MMP-8 and TIMP-1 levels in induced sputum and their expression in airway inflammatory cells of healthy children (n = 27) and of children with newly diagnosed asthma with mild (n = 20) or moderate symptoms (n = 19), before and after 6 months of treatment with inhaled budesonide. RESULTS: At baseline, MMP-8 was higher in asthmatic children with moderate symptoms, TIMP-1 was lower and the MMP-8/TIMP-1 ratio was higher in both groups of asthmatic children compared with controls. Inhaled budesonide increased TIMP-1 levels in both groups of asthmatic children and normalized the MMP-8/TIMP-1 ratio, and this paralleled the improvement in forced expiratory volume in 1 s in children with mild symptoms. At baseline, asthmatic children had significantly more MMP-8-positive macrophages than control children, whereas the number of TIMP-1-positive macrophages was almost the same. Budesonide decreased the percentage of MMP-8-positive macrophages and increased that of TIMP-1-positive macrophages; these changes were significant in asthmatic children with mild symptoms. CONCLUSIONS: Inhaled budesonide normalized the MMP-8/TIMP-1 ratio in asthmatic children by upregulation of TIMP-1 production and downregulation of MMP-8 production by airway macrophages. This change may be a biochemical marker of an effect on airway inflammation and possibly of an ongoing remodeling process that should be further investigated using biopsy specimens.

Neuropeptide S receptor 1 expression in the intestine and skin--putative role in peptide hormone secretion.

Neuropeptide S receptor 1 (NPSR1) was recently found to be genetically associated with inflammatory bowel disease in addition to asthma and related traits. Epithelia of several organs express NPSR1 isoforms A and B, including the intestine and the skin, and NPSR1 appears to be upregulated in inflammation. In this study, we used cell lines and tissue samples to characterize the expression of NPSR1 and its ligand neuropeptide S (NPS) in inflammation. We used polyclonal and monoclonal antibodies to investigate the expression of NPS and NPSR1 in intestinal diseases, such as celiac disease and food allergy, and in cutaneous inflammatory disorders. We found that NPSR1-A was expressed by the enteroendocrine cells of the gut. Overall, the expression pattern of NPS was similar to its receptor suggesting an autocrine mechanism. In an NPSR1-A overexpressing cell model, stimulation with NPS resulted in a dose-dependent upregulation of glycoprotein hormone, alpha polypeptide (CGA), tachykinin 1 (TAC1), neurotensin (NTS) and galanin (GAL) encoding peptide hormones secreted by enteroendocrine cells. Because NPSR1 was also expressed in macrophages, neutrophils, and intraepithelial lymphocytes, we demonstrated that stimulation with the pro-inflammatory cytokines tumour necrosis factor alpha and interferon gamma increased NPSR1 expression in the THP-1 monocytic cells. In conclusion, similar to other neuropeptides and their receptors, NPSR1 signalling might play a dual role along the gut-brain axis. The NPS/NPSR1 pathway may participate in the regulation of the peptide hormone production in enteroendocrine cells of the small intestine.

Clinical and laboratory characteristics of Finnish lupus erythematosus patients with cutaneous manifestations.

Our objective was to characterize clinical features, laboratory findings, concomitant autoimmune diseases, and smoking habits of lupus erythematosus subgroups in genetically homogeneous patients from two Dermatology Departments of Finnish University hospitals. One hundred and seventy eight discoid lupus erythematosus, 55 subacute cutaneous lupus erythematosus, and 77 systemic lupus erythematosus patients were enrolled using patients' charts from institutional database (1995-2006) and during routine control visits. Clustering analysis was performed to reveal natural groupings. Smoking at the onset of disease was significantly more common in all subgroups (57% for discoid lupus erythematosus, 35% for subacute cutaneous lupus erythematosus, and 34% for systemic lupus erythematosus) compared with the age/gender-matched prevalence in the Finnish population, suggesting smoking to be a trigger factor for cutaneous lupus. Leukopenia (38%) and lymphopenia (52%) were observed more often in patients with systemic lupus erythematosus than reported previously. Photosensitivity characterized all groups, especially patients with subacute cutaneous lupus erythematosus (87%). Of the autoimmune diseases, Sjögren's syndrome was the most common (22% of patients with systemic lupus erythematosus), followed by autoimmune thyroid disease (13% of patients with subacute cutaneous lupus erythematosus). The clustering analysis showed environmental factors (smoking) to be more involved in disease development in discoid lupus erythematosus, whereas immunological factors were more significant in initiating systemic lupus erythematosus. The high prevalence of autoimmune thyroid disease, together with photosensitivity, and the clustering profiles suggest that lupus erythematosus subtypes, especially discoid lupus erythematosus, are heterogeneic in their pathomechanisms.

Matrix metalloproteinases as mediators of tissue injury in different forms of cutaneous lupus erythematosus.

BACKGROUND: Matrix metalloproteinases (MMPs) contribute to tissue destruction, regeneration, inflammation and apoptosis and several of them are upregulated by ultraviolet (UV) radiation in skin. Although some MMPs associate with organ manifestations of systemic lupus erythematosus (SLE), their role in cutaneous lupus erythematosus (LE) is elusive. OBJECTIVES: Our aim was to evaluate the expression of MMPs in SLE, subacute cutaneous LE (SCLE) and discoid LE (DLE) skin lesions and their relation to apoptosis and epidermal changes. METHODS: Lesional skin biopsies from 20 patients with SLE, 20 with DLE and 17 with SCLE, and from UVA/UVB-photoprovoked skin of healthy volunteers were immunostained using antibodies to multiple MMPs and tissue inhibitors of metalloproteinases (TIMPs). The TUNEL (terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick end labelling) method was used for detection of apoptosis. RESULTS: MMP-3, -10, -19 and -26 were abundantly expressed by keratinocytes in SLE, DLE and SCLE skin samples. MMP-7 was detected in keratinocytes in regions of oedema and vacuolization especially in SLE and SCLE, while MMP-14 was only occasionally observed in keratinocytes. Photoprovocation did not induce MMP-10 or -26 expression in skin of healthy volunteers. Epithelial TIMP-1 expression was low while occasional positive fibroblasts were seen in the dermis. TIMP-3 was abundantly expressed in the epidermis, endothelial cells and macrophages. CONCLUSIONS: Different subtypes of cutaneous LE are fairly similar in their MMP expression profile. MMP-3 and -10 mediate both epidermal changes and dermal tissue remodelling but are not present in lymphocytes. Low expression of TIMP-1 suggests that lupus skin is characterized by proteolytic events, and targeted action using selective MMP inhibitors may reduce lupus-induced damage in inflamed tissues.

Endothelial cell KIT expression in human tumours.

Receptor tyrosine kinases expressed in endothelial cells are potential targets for therapy with specific tyrosine kinase inhibitors. Endothelial cell KIT expression has not been systematically evaluated in human cancer. In the present study, endothelial cell KIT expression was assessed in 345 tumours consisting of 34 different histological types using a tissue microarray technique. Marked KIT expression occurred in the tumour endothelial cells only in primary glioblastomas in the microarray. Moderate to strong KIT and phosphorylated KIT expression was detected in the tumour endothelial cells in six (16%) and seven (19%) of the 37 primary glioblastomas examined, respectively. In whole tissue sections, KIT and phosphorylated KIT were expressed in tumour endothelial cells in 13 (59%) and 11 (50%) of the 22 glioblastomas examined, respectively. RNA in situ hybridization showed KIT mRNA expression in most glioblastomas both in tumour vessel endothelial cells and in perinecrotic palisading glioblastoma cells, whereas little KIT mRNA was found in the endothelial cells of colon or pancreatic carcinomas. Phosphorylated KIT, its ligand stem cell factor, and the downstream signalling molecules phosphorylated Akt and mTOR were often expressed in glioblastoma cells located in the perinecrotic tumour areas that often also contained abundant HIF-1alpha. It is concluded that marked KIT and phosphorylated KIT expression is frequently present in the endothelial cells of glioblastomas, which are known to harbour florid microvascular proliferation with characteristic morphological features. Glioblastomas also express phosphorylated KIT and its activated downstream signalling molecules in the tumour cells. Lower levels of KIT and phosphorylated KIT are present in endothelial cells of other tumour types and in normal tissues. Endothelial cell and tumour cell expression of activated KIT might explain in part the responsiveness of glioblastomas to the combination of imatinib (an inhibitor of KIT) and hydroxyurea.

Expression of matrix metalloproteinase (MMP)-7 and MMP-13 and loss of MMP-19 and p16 are associated with malignant progression in chronic wounds.

BACKGROUND: The risk of squamous cell carcinoma (SCC) is significantly increased in chronic leg ulcers. Very little is known about the molecular pathogenesis of these tumours, which are often undiagnosed for a long time. As matrix metalloproteinases (MMPs) are implicated at all stages of tumorigenesis, we investigated whether the pattern of epithelial MMP expression can predict development of SCC from pseudoepitheliomatous hyperplasia of chronic wounds. METHODS: Samples from nine patients with SCCs that had arisen in chronic wounds and 31 with venous leg ulcers were studied using immunohistochemistry for MMP-7, MMP-8, MMP-9, MMP-13, MMP-19 and the tumour suppressor p16. In situ hybridization was performed for MMP-1, MMP-3, MMP-7, MMP-12 and MMP-13. RESULTS: MMP-7 was expressed by malignantly transformed epithelium, while it was absent from chronic wounds. MMP-9 was detected in the epithelium in both SCCs and chronic wounds. Epithelial MMP-13 expression was strong in SCC, but was absent in chronic wounds. MMP-12 was expressed in the epithelium in two SCCs, while macrophages were positive in chronic wounds. MMP-19 was induced in proliferating epithelium of wounds, but was absent from invasive areas of SCC. p16 was expressed by keratinocytes in half of the chronic wounds and at superficial margins of SCCs, while invasive areas were negative. CONCLUSIONS: Our results suggest that epithelial expression of MMP-7, MMP-12 and MMP-13, but not that of MMP-1, MMP-3, MMP-8, MMP-9 and MMP-10, in chronic wounds provides a diagnostic clue for distinguishing SCCs from nonmalignant wounds. The loss of MMP-19 and p16 from the epithelium could aid in making the differential diagnosis between well-differentiated SCCs and nonmalignant chronic wounds.

Epithelial tissue-type plasminogen activator expression, unlike that of urokinase, its receptor, and plasminogen activator inhibitor-1, is increased in chronic venous ulcers.

BACKGROUND: The plasminogen activation system represents a potent mechanism of extracellular proteolysis and is an essential component of normal wound healing. It has also been implicated in the pathogenesis of chronic, nonhealing ulcers. Traditionally, urokinase-type plasminogen activator (uPA) has been associated with pericellular proteolytic activity involved in tissue remodelling processes, and tissue-type plasminogen activator (tPA) mainly with intravascular fibrinolysis. OBJECTIVES: The present study was conducted to characterize the spatial distribution of the various plasminogen activation system components in chronic ulcers and acute, well-granulating wounds. METHODS: The expression of uPA, tPA, urokinase receptor (uPAR), plasminogen activator inhibitor-1 (PAI-1), and vitronectin was investigated by immunohistochemical staining, in addition to uPA, tPA and PAI-1 expression by in-situ hybridization, in samples from eight chronic venous ulcers, five decubitus ulcers, five well-granulating acute wounds and five normal skin samples. RESULTS: In chronic venous leg ulcers tPA mRNA was detected in basal and suprabasal keratinocytes at the leading wound edge, while in well-granulating wounds and in decubitus ulcers tPA mRNA was expressed only in a few keratinocytes. However, tPA was widely expressed in fibroblast- and macrophage-like cells in the stroma of well-granulating wounds, while less tPA was detected in the granulation tissue of chronic ulcers. tPA mRNA and protein were localized in the superficial granular layers in normal skin. Although no qualitative differences in expression of uPA, PAI-1 or uPAR in the wound edge keratinocytes in chronic ulcers vs. normally granulating wounds were found, their expressions were more pronounced in the granulation tissue of well-granulating wounds. CONCLUSIONS: These results suggest that in poorly healing venous leg ulcers, the pattern of tPA expression is altered in keratinocytes at the leading edge of the wound, and the patterns of tPA, uPA and PAI-1 expression are altered in the granulation tissue.

Collagenase-1 (MMP-1), matrilysin-1 (MMP-7), and stromelysin-2 (MMP-10) are expressed by migrating enterocytes during intestinal wound healing.

BACKGROUND: Matrix metalloproteinases (MMPs) play a crucial role in wound healing of the skin, airways, and cornea, but data on MMPs in normal intestinal wound healing is limited. The aim of this study was to clarify the role of collagenase-1 (MMP-1), matrilysin-1 (MMP-7), and stromelysin-2 (MMP-10) in intestinal wound repair and to determine the effect of cytokines on the expression of these MMPs in intestinal epithelial cell lines. METHODS: Surgical specimens from patients with ischemic colitis (n = 5) were used as an in vivo model of intestinal re-epithelialization. Fetal ileal explants were used as an ex vivo model. In situ hybridization for MMPs -1, -3, -7, and -10 was performed and immunohistochemical stainings were used to localize MMP-7 and -9 expressing cells. Stainings for cytokeratin and laminin-5 were performed to identify epithelial cells and migrating enterocytes, respectively. Caco-2, HT-29, and WiDr cell lines were treated for 6-48 h with different cytokines (e.g. EGF, KGF, IL-1 beta, TGF-alpha, TNF-alpha, and TGF-beta1) and Taqman real-time quantitative RT-PCR was used to investigate their effect on the expression of MMPs-1, -7, and -10. RESULTS: MMP-7, MMP-10, and MMP-1 were expressed by migrating enterocytes bordering intestinal ulcers in 5/5, 3/5, and 3/5 samples, respectively. In the fetal gut model, MMP-1 and MMP-10 were expressed by migrating enterocytes, but matrilysin-1 expression was not detected. Matrilysin-1 was up-regulated by TNF-alpha and IL-1 beta, and stromelysin-2 by TNF-alpha and EGF in Caco-2 and WiDr cell cultures. MMP-1 was up-regulated in Caco-2 cells by TGF-beta, EGF, and IL-1 beta, but only by EGF in WiDR cells. CONCLUSIONS: It is concluded that collagenase-1, stromelysin-2, and matrilysin-1 are involved in intestinal re-epithelialization in vivo and that they are up-regulated by cytokines relevant in wound repair.

Differential expression of three matrix metalloproteinases, MMP-19, MMP-26, and MMP-28, in normal and inflamed intestine and colon cancer.

Several matrix metalloproteinases (MMPs) have been implicated in intestinal inflammation, mucosal wound healing, and cancer progression. The purpose of this study was to examine the cellular location and putative function of MMP-19, MMP-26 (matrilysin-2), and MMP-28 (epilysin), in normal, inflammatory, and malignant conditions of the intestine. Peroperative tissue specimens from patients with ulcerative colitis (UC) (n = 16) and archival tissue samples of ischemic colitis (n = 9), Crohn's disease (n = 7), UC (n = 8), colon cancer (n = 20), and healthy intestine (n = 5) were examined using immunohistochemical analyses with polyclonal antibodies. Unlike many classical MMPs, MMP-19, MMP-26, and MMP-28 were all expressed in normal intestine. In inflammatory bowel disease (IBD), MMP- 19 was expressed in nonmigrating enterocytes and shedding epithelium. MMP-26 was detected in migrating enterocytes, unlike MMP-28. In colon carcinomas, MMP-19 and MMP-28 expression was downregulated in tumor epithelium. Staining for MMP-26 revealed a meshwork-like pattern between cancer islets, which was absent from most dedifferentiated areas. Our results suggest that MMP-19 is involved in epithelial proliferation and MMP-26 in enterocyte migration, while MMP-28 expression is not associated with inflammatory and destructive changes seen in IBD. In contrast to many previously characterized MMPs, MMP-19 and MMP-28 are downregulated during malignant transformation of the colon and may play a prominent role in tissue homeostasis.

Differential expression of matrilysin-1 (MMP-7), 92 kD gelatinase (MMP-9), and metalloelastase (MMP-12) in oral verrucous and squamous cell cancer.

Squamous cell carcinoma (SCC) of the oral cavity is a highly invasive tumour of stratified squamous epithelium that spreads through degradation of the basement membrane (BM) and extracellular matrix (ECM). There are currently no reliable tissue or serum markers to predict whether the tumour has metastasized at the time of diagnosis. Verrucous carcinoma (VC) of the oral cavity is a rare low-grade variant of oral SCC that penetrates into the subepithelial connective tissue. Many matrix metalloproteinases (MMPs), such as MMP-1, -2, -7, -9, -13, and -14, as well as integrin receptors have been implicated in cancer invasion. Integrin alphavbeta6 is induced in SCC and appears to be involved in up-regulation of MMP-9 expression by oral keratinocytes and promotion of their migration. The aim of this study was to investigate whether the pattern of MMP expression or that of alphavbeta6 integrin contributes to the differences in the biological behaviour of oral SCC and VC. The results show that the less aggressive nature of oral VC may be connected to its MMP expression profile. Typically, VCs were devoid of epithelial MMP-3, -7, -9, -12 and -13 expression, compared with SCCs. MMP-19 was expressed by epithelial keratinocytes in hyperproliferative areas of verrucous hyperplasia, VC, and SCC, but was absent in the invasive cancer cell nests of SCC. MMP-26 was expressed by hyperproliferative keratinocytes in VC as well as by invasive cancer cells in SCCs. MMP-10 was expressed widely in the epithelium of all SCC specimens. alphavbeta6 integrin expression was also detected in some cases of epithelial hyperplasia but was significantly more abundant in cancers at the invasive front. The absence of MMP-7, -9 and -12 from epithelial cells may serve as a good prognostic marker of non-invasive oral carcinoma. Blocking the activity of invasion-specific MMPs or alphavbeta6 integrin might offer novel therapeutic modalities in early-stage oral carcinoma.

Matrix metalloproteinases in tumor progression: focus on basal and squamous cell skin cancer.

Many normal biological processes, such as reproduction, fetal development and wound healing, are critically dependent on controlled degradation of extracellular matrix (ECM) macromolecules. However, excessive degradation of matrix components occurs in pathologic tissue destruction, e.g. in atherosclerosis, rheumatoid arthritis, and cancer. Matrix metalloproteinases (MMPs) are degradative enzymes that play an important role in all aspects of tumor progression by enhancing tumor-induced angiogenesis and destroying local tissue architecture and basement membranes to allow tumor invasion and metastasis. Efficient breakdown of the ECM surrounding invasive cancer islands involves interplay between tumor cells, stromal cells, and inflammatory cells, all of which express a distinct set of MMPs. Besides the classical role of MMPs in degradation of ECM, MMPs may also indirectly influence the tumor microenvironment through the release of growth factors, cryptic sites or angiogenic factors, or through the generation of matrix fragments that inhibit tumor cell proliferation, migration and angiogenesis. This makes the contribution of MMPs to tumorigenesis much more complex than initially thought. Currently, a number of clinical studies have focused on testing MMP inhibitors as potential antineoplastic agents. In this review we discuss the present role of MMPs in the development and progression of cancer, focusing on non-melanoma skin cancers basal (BCC) and squamous (SCC) cell carcinoma, and the possible influence of MMPs in their differences.

Overexpression of tissue inhibitor of metalloproteinases-3 in intestinal and cutaneous lesions of graft-versus-host disease.

Matrix metalloproteinases (MMPs) have been implicated in the pathobiology of various T-cell-mediated inflammatory disorders of the intestine and skin. Their synthetic inhibitor has been shown to prevent lethal acute graft-versus-host disease in animal models. We intended to determine the expression of MMPs 1, 3, 7, 9, 10, 12, and 19 and tissue inhibitors of metalloproteinases (TIMPs) 1 and 3 in intestinal and cutaneous lesions of patients suffering from graft-versus-host disease after bone marrow transplantation. In situ hybridizations for MMPs 1, 3, 7, 10, and 12 as well as TIMPs 1 and 3 were performed using (35)S-labeled cRNA probes on intestinal (n = 13) and cutaneous specimens (n = 9) from patients with graft-versus-host disease. Immunohistochemical stainings were carried out to localize MMP-9, MMP-19, TIMP-3, and TGF-beta1 proteins, and TUNEL staining, to detect apoptotic cells. TIMP-3 mRNA and protein were detected in cutaneous lesions in areas with vacuolar degeneration of the basal epidermal layer in all skin samples, and they colocalized with apoptotic keratinocytes and partly with staining for TGF-beta. None of the MMPs examined were overexpressed in skin lesions. Signals for MMP-1 and MMP-3 mRNA was found in 10/13 and 5/13 intestinal biopsies, respectively. In the gut, MMP-19-positive epithelial cells, particularly in the crypts, were found in 10/13 samples. Expression of MMPs 7, 9, 10, and 12 was absent or very low. TIMPs 1 and 3 were expressed by stromal cells in 12/13 and 10/13 gut samples, respectively. Whereas TIMP-1 was expressed particularly by subepithelial cells where epithelium had shed away, TIMP-3 was detected in deeper areas. We conclude that MMPs are differentially regulated in the skin and gut lesions of graft-versus-host disease. In agreement with previous data on cancer cells, TIMP-3, induced by TGF-beta1, may contribute to the apoptosis of keratinocytes in cutaneous graft-versus-host disease lesions, leading to typical histopathological changes. We also conclude that MMPs play a less important role as effector molecules in intestinal graft-versus-host disease than in celiac or inflammatory bowel disease.

Upregulation of matrix metalloproteinases in a model of T cell mediated tissue injury in the gut: analysis by gene array and in situ hybridisation.

BACKGROUND AND AIM: Matrix metalloproteinases (MMPs) have been implicated in tissue remodelling and ulceration in inflammatory bowel disease and coeliac disease. Studies to date have concluded that stromelysin 1 is functionally involved in mucosal degradation. However, there are many other MMPs whose function in the gut is currently unknown. This work had two aims: firstly, to use gene array technology to measure changes in MMP and tissue inhibitor of metalloproteinase (TIMP) expression in a model of T cell mediated injury in the gut, and secondly, to correlate data from gene arrays with that generated by in situ hybridisation. METHODS: T cells in explants of human fetal gut were activated with pokeweed mitogen or anti-CD3 plus interleukin 12. Gene array analysis and in situ hybridisation were performed to investigate changes in MMP gene expression. RESULTS: Both gene array analysis and in situ hybridisation indicated marked upregulation of stromelysin 2 and macrophage metalloelastase expression in the explants associated with mucosal destruction. The arrays also confirmed our previous observation that interstitial collagenase (MMP-1), stromelysin 1 (MMP-3), and gelatinase B (MMP-9) are upregulated but there was no change in MMP-2, -7, -8, -9, -11, -13, -14-17, or -19. Following T cell activation, transcripts for TIMPs were reduced. CONCLUSIONS: These results show that there is differential upregulation of MMPs during T cell responses in the gut and suggest that further studies on the role of stromelysin 2 and macrophage metalloelastase may show that they have a functional role. In addition, the increase in MMPs and reduction in TIMPs suggest that the protease/antiprotease balance in the mucosa may determine the extent of mucosal degradation.

Matrilysin (matrix metalloproteinase-7) expression in human junctional epithelium.

Matrilysin is a matrix metalloproteinase expressed in exocrine and mucosal epithelium in many human tissues. Immunohistochemical staining showed that matrilysin is expressed in suprabasal cells of junctional epithelium facing the teeth and in epithelial cell rests of Malassez. No matrilysin expression was seen in the periodontal pocket tissue. In a tissue culture model mimicking junctional epithelium, matrilysin expression was also observed in suprabasal epithelial cells. Of 13 anaerobic oral bacterial species tested, F. nucleatum, F. necrophorum, P. endodontalis, and P. denticola stimulated matrilysin expression in porcine periodontal ligament epithelial cells from 2.5- to 5.7-fold, compared with untreated cells. The enzyme was localized in intracytoplasmic vesicles that also reacted with antibodies against lysosomal membrane protein h-lamp-1. The results indicate that matrilysin may play an important role in the normal physiology of junctional epithelium.

Human macrophage metalloelastase (MMP-12) expression is induced in chondrocytes during fetal development and malignant transformation.

Fetal development and tumor progression both require a complex system of extracellular matrix (ECM) synthesis and breakdown, which is mediated by, for instance, the matrix metalloproteinases (MMPs). Human metalloelastase (MMP-12) is an MMP, the expression of which has so far been documented in macrophages associated with atherosclerosis, wound repair, and certain cancers. In this study we first examined the expression of MMP-12 during human fetal development. By in situ hybridization MMP-12 transcripts were detected in chondrocytes of hypertrophic cartilage in vertebrae of the spinal column, in ribs, and in extremities undergoing ossification, beginning at the gestational age of 8 weeks. Also, periosteal cells expressed MMP-12 at 11 weeks. No expression of MMP-12 mRNA could be noted in other fetal tissues, including the skin, lungs, intestine, kidney, and liver. Expression of MMP-12 mRNA could not be detected in adult normal cartilage or osteosarcomas, but in chondrosarcomas both macrophages (8 of 19 samples) (identified by CD68 immunostaining) and chondrosarcoma cells (8 of 19) were positive. MMP-12 was also demonstrated in the tumors by western blotting and it was expressed in the same regions as MMP-13 mRNA. By immunostaining, MMP-12 mRNA colocalized with the protein in both fetal and chondrosarcoma specimens. Unlike basic fibroblast growth factor (bFGF) and transforming growth factor-beta (TGF-beta), tumor necrosis factor-alpha (TNF-alpha) induced MMP-12 mRNA production in chondrosarcoma-derived HTB-94 cells. Our results suggest that MMP-12 plays an important role in ECM remodeling during fetal bone development and is induced when chondrocytes undergo malignant transformation.

Topical synthetic inhibitor of matrix metalloproteinases delays epidermal regeneration of human wounds.

Matrix metalloproteinases (MMPs) degrade extracellular proteins during epithelialization of wounds. To evaluate the biological significance of MMPs in epidermal healing, the synthetic broad-spectrum MMP inhibitor GM 6001 (also called Galardin and Ilomastat) was applied topically to standardized human wounds. GM 6001 (10 microg/microl) or vehicle alone was applied every second day onto 4 de-roofed 6 mm suction blister wounds on the volar forearm of healthy male volunteers for 12 days. GM 6001 delayed healing by 2-4 days as assessed macroscopically and microscopically. In situ hybridization or immunohistochemistry showed that MMP-1 (interstitial collagenase) was present in and MMP-2 (gelatinase A) close to laterally migrating keratinocytes whereas MMP-9 (gelatinase B) was seen during maturation of new epidermis. MMP-1 was undetectable in blister roofs (normal epidermis) and found in low levels in normal skin. Total MMP-1 activities increased about 100-fold in wounds, independent of treatment, compared to normal skin as analyzed by specific ELISA-based activity assay. By gelatin zymography, MMP-2, but not MMP-9, was detected in blister roofs and wound healing was associated with increased active MMP-2 and latent MMP-9 levels. GM 6001 prevented activation of MMP-2 and increased latent MMP-9 levels. GM 6001 delayed re-appearance of laminin-5, the synthesis of which correlated with epidermal regeneration. Restoration of stratum corneum, measured indirectly by transepidermal water loss, was also impaired (P<0.05) in the GM 6001 group. In conclusion, pharmacological MMP inhibition delayed epidermal regeneration in vivo, suggesting that MMPs are required to restore epidermis after epidermal ablation in humans.

Ultrastructural features resembling those of harlequin ichthyosis in patients with severe congenital ichthyosiform erythroderma.

Congenital ichthyoses are a group of heterogeneous disorders of cornification. Autosomal recessive congenital ichthyosis (ARCI) can be clinically subdivided into congenital ichthyosiform erythroderma and lamellar ichthyosis. Ultrastructurally, ARCI is classified into four groups: ichthyosis congenita (IC) types I-IV. The genetic background of the ARCI disorders is heterogeneous, but only one disease gene, transglutaminase 1, has been detected so far. We describe six patients with severe congenital ichthyosis from six different Scandinavian families. They could not be classified ultrastructurally into the four IC groups because of atypical findings of electron microscopy. These included abnormal lamellar bodies, alterations in keratohyalin, remnant organelles and lipid inclusions in the upper epidermal cells, which resembled the ultrastructural findings of harlequin ichthyosis (HI), although the HI phenotype was not present at birth. Some clinical features, such as thick scales, erythroderma, alopecia and ectropion were common to all patients. Ichthyosis was usually accentuated in the scalp and four patients had clumped fingers and toes. None of the patients carried the transglutaminase 1 mutation. We conclude that ultrastructural findings resembling those detected in previous HI cases (type 1 and 2) can also be found in patients who do not have classic clinical features of that rare ichthyosis. This may be due to lack of specificity of ultrastructural markers for HI or to its clinical heterogeneity.

Upregulation and differential expression of matrilysin (MMP-7) and metalloelastase (MMP-12) and their inhibitors TIMP-1 and TIMP-3 in Barrett's oesophageal adenocarcinoma.

Oesophageal adenocarcinoma is believed to arise from metaplastic mucosa in the distal oesophagus, a condition also known as Barrett's oesophagus (BE). BE develops as a result of injury caused by refluxing gastric and duodenal contents and is associated with increased risk of malignant transformation. Matrix metalloproteinases (MMPs) have been implicated in all aspects of tumour progression; tumour growth, basement membrane degradation, invasion and metastatic spread. Using in situ hybridization, we investigated the expression patterns of collagenases-1 and -3, stromelysin-2, matrilysin, metalloelastase and TIMPs-1 and -3 in BE, adenocarcinoma and lymph-node metastases. Matrilysin was expressed abundantly in 12/15 tumours and in 4/6 lymph-node metastases and its expression correlated with the histological aggressiveness of tumour. Matrilysin and metalloelastase were upregulated already in BE. Stromelysin-2 and collagenase-3 expression was detected only in a few tumours. Collagenase-1 was expressed by cancer and stromal cells in 9/15 tumours. Tumour-infiltrating macrophages expressed metalloelastase in 13/15 cancers. TIMPs-1 and -3 were expressed in 12/15 and 11/15 tumours, respectively. Laminin-5 and tenascin were abundantly expressed at the invasive front of poorly differentiated tumours, but not in BE. Our results indicate that matrilysin is the principal MMP expressed by tumour cells in oesophageal adenocarcinoma, and further studies are needed to investigate whether matrilysin or tenascin-C could be used as a predictive marker for progression of BE to cancer.

SLC26A2 (diastrophic dysplasia sulfate transporter) is expressed in developing and mature cartilage but also in other tissues and cell types.

Mutated alleles of the SLC26A2 (diastrophic dysplasia sulfate transporter or DTDST) gene cause each of the four recessive chondrodysplasias, i.e., diastrophic dysplasia (DTD), multiple epiphyseal dysplasia (MED), atelosteogenesis Type II (AO2), and achondrogenesis Type IB (ACG1B). SLC26A2 acts as an Na(+)-independent sulfate/chloride antiporter and belongs to the SLC26 anion transporter gene family, currently consisting of six homologous human members. Although Northern analysis has indicated some expression in all tissues studied, the only tissue known to be affected by SLC26A2 mutations is cartilage. Abundant SLC26A2 expression has previously been detected in normal human colon by in situ hybridization. We have used in situ hybridization and immunohistochemistry to examine multiple normal tissues for the expression of human SLC26A2. As expected, a strong signal for SLC26A2 mRNA and protein immunostaining were detected in developing fetal hyaline cartilage, while bronchial cartilage showed mRNA expression in adult tissues. SLC26A2 expression could also be detected in eccrine sweat glands, in bronchial glands, and in placental villi. In addition, immunoreactivity for the SLC26A2 protein was observed in exocrine pancreas. Our results suggest a more limited expression pattern for SLC26A2 than that found by Northern analysis. However, SLC26A2 expression is also detected in tissues not affected in chondrodysplasias caused by SLC26A2 mutations.