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.
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.
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.
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.
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.
"There was low expression of TIMP-1 in the epidermis and in the dermal fibroblasts which was interpreted as the main cause for increased proteolysis . TIMP-3, however, was overexpressed in the epidermis , endothelial cells and macrophages (Järvinen et al, 2007). These results highlight the potential consequence toward degradation of the epidermis due to imbalance between MMPs and their inhibitors which lead to the formation of skin lesions. "
[Show abstract][Hide abstract] ABSTRACT: Matrix metalloproteinases (MMPs) are critical factors in maintaining the integrity of mucosa and mediating normal biological processes. An imbalance between tissue levels of these mediators and their natural inhibitors is believed to underlie the pathophysiology of many diseases, including those affect the gastrointestinal and oral mucosae. The ongoing development of synthetic inhibitors of these mediators may provide opportunities to develop treatment modalities for patients suffering from these diseases. Understanding the role of MMPs in the pathophysiology of many diseases, however, is far from complete, and the improvement of pharmaceutical management strategies can only be achieved if the underlying process of these diseases is completely comprehended. This paper reviews the functions of matrix metalloproteinases and addresses their role in mediating mucosal pathologies with emphasis on oral mucosa.
[Show abstract][Hide abstract] ABSTRACT: Klf4, one of the highly expressed transcription factors in the mouse cornea, plays an important role in maturation and maintenance of the ocular surface. In this study, the structure and proteoglycan composition of the Klf4 conditional null (Klf4CN) corneal stroma was investigated, to further characterize the previously reported Klf4CN stromal edema.
Collagen fibril spacing and diameter were calculated from scattering intensity profiles from small angle synchrotron x-ray scattering patterns obtained across the cornea along a vertical meridian at 0.5-mm intervals. Collagen fibril organization and proteoglycans were visualized by electron microscopy (EM), with or without the cationic dye cuprolinic blue. Proteoglycans and glycosaminoglycans were further analyzed by fluorophore-assisted carbohydrate electrophoresis (FACE) and immunoblot analysis. Q-RT-PCR was used to measure the transcript levels.
In the central cornea, the average collagen interfibrillar Bragg spacing increased from 44.5 nm (SD +/-1.8) in wild-type to 66.5 nm (SD +/-2.3) in Klf4CN, as measured by x-ray scattering and confirmed by EM. Mean collagen fibril diameter increased from 32 nm (SD +/-0.4) in wild-type to 42.3 nm (SD +/-4.8) in Klf4CN corneal stroma. Downregulation of proteoglycans detected by EM in the Klf4CN stroma was confirmed by FACE and immunoblot analysis. Q-RT-PCR showed that, whereas the Klf4CN corneal proteoglycan transcript levels remained unchanged, matrix metalloproteinase (MMP) transcript levels were significantly upregulated.
The Klf4CN corneal stromal edema is characterized by increased collagen interfibrillar spacing and increased diameter of individual fibrils. The stroma also exhibits reduced interfibrillar proteoglycans throughout, which is possibly caused by increased expression of MMPs.
[Show abstract][Hide abstract] ABSTRACT: Skin cancers are the most frequent malignancies in organ transplant recipients (OTRs). Squamous cell carcinomas (SCCs) occur 65-250 times more frequently in OTRs and tend to be aggressive in behavior. Because matrix metalloproteinases (MMPs) have a central role in tumorigenesis and invasion, we investigated the epithelial and stromal MMP and tissue inhibitor of MMP (TIMP) expression profile in SCCs of immunosuppressed (IS) compared with immunocompetent (IC) patients to determine if differences could explain the more aggressive behavior of SCCs in OTRs.
Matched pairs from 20 SCCs of IS and IC patients were studied using immunohistochemistry for MMP-1, MMP-7, MMP-8, MMP-9, MMP-13 and MMP-26 and TIMP-1 and TIMP-3.
Among all MMPs studied, only staining for MMP-26 was significantly more intense in cancer cells of the post-transplant group compared with the IC group (p = 0.01), whereas MMP-9 expression was more abundant in stromal macrophages surrounding SCCs of IC patients (p = 0.02). MMP-26 expression in cancer cells (p = 0.04) and that of MMP-9 in neutrophils (p = 0.005) were more abundant in SCCs of patients using cyclosporine.
We conclude that MMP-26 and MMP-9 may contribute to the more aggressive behavior of SCCs in OTRs.
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