Temporal and spatial expression of matrix metalloproteinases during wound healing of human corneal tissue (original) (raw)
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Role of matrix metalloproteinases in failure to re-epithelialize after corneal injury
The American journal of pathology, 1996
Delayed re-epithelialization of the cornea after injury usually precedes stromal ukceration. Previous findings using a rat thermal injury model suggested that re-epithelialization is impeded by products of resident corneal cells, which destroy adbesive structures at the basement membrane zone. In this study, we provide additional evidencefor this concept. Failure to re-epithelialize was found to correlate with an increase in the amounts of gelatinolytic matrix metalloproteinases present in the rat cornea. One of these gelatinases, gelatinase B, is synthesized by the resident corneal cells, and inhibition of its synthesis correlated with inhibition of basement membrane dissolution. The matrix metalloproteinases collagenase and stromelysin are also synthesized by resident corneal cells in thermaly injured corneas of rabbits, but the timing of bulk enzyme synthesis correlated more closely with deposition of repair tissue in the stroma than with failure to re-epithelialize. Nevertheless, in human corneas with repair defects, gelatinase B and collagenase are synthesized by cells in the basal layer of the epithelium directly adjacent to the basement membrane, suggesting that both couldparticipate in dissolution ofthis structure. Importantly, treatment of thermally injured corneas with a synthetic inhibitor of matrix metalloproteinases significantly improved basement membrane integrity. These data support the concept that over-expression of matrix metalloproteinases by resident corneal cells impedes re-epithelialization after some types ofcorneal injury. (Am J Pathol 1996, 149:1287-1302 Corneal ulceration is a devastating disorder that can cause blindness. Ulcers manifest as a breakdown of the collagenous stromal tissue, a process that was once thought to be a simple physical dissolution described as corneal melting. A major change in our understanding of stromal ulceration occurred when this process was shown to be associated with the secretion of type collagen-degrading enzymes from living cells.' In organ culture, collagenolytic activity was shown to be produced by superficial sections of ulcerating cornea containing the epithelial layer and a small amount of anterior stroma. However, the observation that neutrophil infiltration is a hallmark of stromal ulceration suggested that these cells (with their accumulated stores of hydrolytic enzymes) might provide the more important source of collagenase. Experiments showing that chemical injuries do not ulcerate in animals that have been made neutropenic have provided support for this hypothesis.2
Protective effects of matrix metalloproteinase-12 following corneal injury
Journal of Cell Science, 2013
Corneal scarring due to injury is a leading cause of blindness worldwide and results from dysregulated inflammation and angiogenesis during wound healing. Here we demonstrate that the extracellular matrix metalloproteinase MMP12 (macrophage metalloelastase) is an important regulator of these repair processes. Chemical injury resulted in higher expression of the fibrotic markers α-smooth muscle actin and type I collagen, and increased levels of angiogenesis in corneas of MMP12−/− mice compared with corneas of wild-type mice. In vivo, we observed altered immune cell dynamics in MMP12−/− corneas by confocal imaging. We determined that the altered dynamics owed to an altered inflammatory response, with delayed neutrophil infiltration during the first day and excessive macrophage infiltration six days later, mediated by altered expression levels of chemokines CCL2 and CXCL1, respectively. Corneal repair returned to normal upon inhibition of these chemokines. Taken together, these data sh...
Collagenolytic/Gelatinolytic Enzymes in Corneal Wound Healing
Acta Ophthalmologica, 2009
We have documented changes in expression of collagenolytic/gelatinolytic enzymes of the matrix metalloproteinase family (MMP) in healing or ulcerating corneal wounds of rat or rabbit. Correlation of our findings with specific changes in the extracellular matrix of the repair tissue suggests two different roles for the enzymes, MMP-2 and MMP-9. MMP-2 is expressed in undamaged corneal stroma where it may degrade the occasional collagen molecule that becomes damaged. After corneal wounding, expression of this enzyme is increased and much of it appears in the active form. These changes persist for at least seven months, suggesting that MMP-2 is involved in the prolonged process of collagen remodelling in the stromal repair tissue. MMP-9 is expressed in the epithelial layer of repair tissue with a timing suggesting it might participate in controlling resynthesis of the basement membrane. MMP-9 also appears to be involved in degradation of the epithelial basement membrane that precedes corneal ulceration.
Journal of Cellular Physiology, 2009
Matrix metalloproteinase-9 (MMP-9) is a well known regulator and effecter of many cellular processes including wound healing. In the cornea, either too much or too little MMP-9 can be detrimental to overall wound repair. We investigated the secreted factors as well as the intracellular signaling pathways and the promoter sequences that mediate this regulation. Primary culture rabbit corneal epithelial cells were treated with various cytokines alone or in different combinations and MMP-9 induction was assessed by gel zymography. Pharmacological inhibitors were used to determine the intracellular signaling pathways induced by the cytokines tested and deletion promoter constructs were created to determine the regions of the MMP-9 promoter involved in the cytokine regulation, thereby assessing the exact transcription factors binding the MMP-9 promoter. We found that two cytokine families, TGF-β and IL-1, act additively in an isoform non-specific manner to induce MMP-9 in this cell type. Our data suggest TGF-β mediated MMP-9 induction may be regulated by the NF-kB, Smad3, and JNK pathways, whereas the IL-1β mediated induction may be regulated by the NF-kB and p38 pathways. Inhibition of the p38, NF-kB, or JNK pathways significantly reduced, but did not abrogate, basal MMP-9 levels. Inhibition of the ERK pathway did not have an effect on MMP-9 mediated expression in either the treated or untreated co-transfected cells.
Impaired keratinocyte function on matrix metalloproteinase-1 (MMP-1) damaged collagen
Archives of Dermatological Research, 2009
Healing of superficial skin wounds depends on the proliferation and migration of keratinocytes at the wound margin. When human epidermal keratinocytes were incubated on polymerized type I collagen, they rapidly attached and spread. The cells underwent a proliferative response and, over the subsequent 6-day period, covered the collagen surface with a monolayer of cells. When keratinocytes were plated on collagen that had been fragmented by exposure to matrix metalloproteinase-1 (MMP-1, collagenase-1), the cells attached as readily as to intact collagen but spread more slowly and less completely. Growth was reduced by approximately 50%. Instead of covering the collagen surface, the keratinocytes remained localized to the site of attachment. Keratinocytes on fragmented collagen expressed a more differentiated phenotype as indicated by a higher level of surface E-cadherin. Based on these findings, we suggest that damage to the underlying collagenous matrix may impede efficient keratinocyte function and retard wound closure.
Matrix Metalloproteinase 2 (Gelatinase A) Is Related to Migration of Keratinocytes
Experimental Cell Research, 1999
The role of matrix metalloproteinases (MMPs) in cell migration was studied by measuring cell growth, migration, and production of MMP-2 and -9 in oral mucosal and skin keratinocytes cultured in the presence of synthetic MMP inhibitors. MMP-2 was the major gelatinolytic MMP produced by these cells while MMP-9 was produced at a low basal level. Inhibitor effects on MMP-9 production were therefore studied in keratinocytes stimulated by tumor necrosis factor ␣ (TNF␣). Tetracycline analogues at concentrations that inhibited the production of MMP-2 but not MMP-9 were able to drastically inhibit migration of both mucosal and skin keratinocytes. Tetracycline analogues also inhibited keratinocyte growth, an effect not found for the other inhibitors tested. Heterocyclic carbonate-derived compounds (LWs) that inhibited MMP-9 but not MMP-2 production had no effect on cell migration. Batimastat, a potent MMP inhibitor, did not have any effect on MMP production or cell growth but did inhibit keratinocyte migration. Tumor growth factor  (TGF) increased keratinocyte migration as well as both cell-associated and secreted MMP-2 production in wounded cell cultures. The secreted enzyme was partially converted into an active form. In this model batimastat totally blocked TGF-promoted keratinocyte migration. Immunostaining of keratinocytes advancing into the wound revealed that MMP-2 was localized in extracellular matrix contactlike structures against the endogenously produced laminin-5-rich matrix. MMP-9 was localized diffusely along the cell membranes. Using in situ hybridization we observed that in chronically inflamed human gingiva MMP-2 is expressed in epithelium extending into subepithelial connective tissue. These results suggest that MMP-2 plays a specific role in epithelial migration, possibly by detaching the advancing cells from the pericellular matrix or by activating other MMPs.
Molecular and Cellular Biochemistry, 2005
Disruption of epidermal-mesenchymal communication due to a delay in epithelialization, increases the frequency of developing fibrotic conditions in skin. As matrix metalloproteinases-2 (MMP-2) and -9 (MMP-9) are two key enzymes involved in wound healing and tissue remodeling, here we examined the efficacy of keratinocyte-fibroblast interaction on modulation of these enzymes and their inhibitors. The conditioned media derived from keratinocytes and fibroblasts grown in upper and lower chambers of a co-culture system, respectively, were analyzed for MMP-2 and -9. Keratinocyte or fibroblast conditioned medium (FCM) was used as a control. Gelatinolytic activity analyzed by zymography showed that keratinocytes mainly express MMP-9 and to a lesser extent MMP-2; while fibroblasts express only MMP-2. In a co-culture system, the activities of both MMP-2 and MMP-9 markedly increased in conditioned media collected from bottom chambers. These findings were consistent with the level of MMP-2 and MMP-9 measured by Western blot. Using the same experimental setting, the levels of tissue inhibitors of MMPs (TIMPs) secreted by keratinocytes and fibroblasts grown in the same co-culture system were also evaluated. Western blot showed that fibroblasts secrete only TIMP-1 and TIMP-2 whose levels were increased by co-culturing fibroblasts with keratinocytes. In contrary the level of TIMP-3, which was mainly expressed by keratinocytes, increased by co-culturing these cells with fibroblasts. In conclusion, interaction of fibroblast-keratinocyte modulates the levels of MMP-2 and -9 and their inhibitors produced by these cells and this interaction may be critical for a better healing quality at a late stage of the wound healing process. (Mol Cell Biochem 269: 209-216, 2005)
Matrix metalloproteinases in disease and repair processes in the anterior segment
Survey of ophthalmology
The pathogenesis of many anterior segment disorders and ocular complications following surgery are secondary to the wound healing response. The extent of clinical damage observed is closely related to the amount of scarring and tissue contraction. Matrix metalloproteinases (MMPs) are a family of enzymes that play a vital role in all stages of the wound healing process. They degrade all extracellular matrix components and also have the ability to synthesize collagen and extracellular matrix members, and are therefore important in the remodeling of a wound. Overexpression of MMPs results in excessive extracellular matrix degradation, leading to tissue destruction and loss of organ function. In the case of the anterior segment, this may mean the loss of visual function. This review focuses on the role MMPs have in the development of various anterior segment disorders. The importance of MMPs in the wound healing response and its potential modulation to manipulate the scarring response is being recognized, and current developments will be described. Surv Ophthalmol 47:239 -256 . © 2002 by Elsevier Science Inc. All rights reserved.) Key words. anterior segment • aqueous humour • ciliary body • conjunctiva • cornea • extracellular matrix • glaucoma • lens • matrix metalloproteinase • trabecular meshwork • uvea • wound healing Surv Ophthalmol 47 (3)