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Differential expression of MT1-MMP (MMP-14) and collagenase III (MMP-13) genes in normal and wounded rat corneas
1Schepens Eye Research Institute and the. Massachusetts Eye and Ear Infirmary Department of Ophthalmology, Harvard Medical School, Boston 02114, USA.
Purpose:
Several members of the matrix metalloproteinase (MMP) group have been identified in the rat cornea during corneal wound healing. The aim of the present study was to identify additional members of the MMP gene family in the rat cornea and localize the expression of membrane type-1 matrix metalloproteinase (MT1-MMP; MMP-14) and collagenase III (MMP-13) in normal and wounded corneas.
Methods:
Adult rats underwent laser keratectomy on the right eye. Unwounded left eyes were normal controls. Corneas were collected and processed at different times post-wounding. Reverse transcription-polymerase chain reaction (RT-PCR) and DNA sequencing were used to discover the MMP genes expressed in the corneas. In situ hybridization was performed to localize the mRNA expression of MMP-14 and MMP-13.
Results:
MMP-13 mRNA was detected in epithelial cells of wounded corneas, but not in normal controls; MMP-14 was found in both normal and wounded corneas. MMP-14 mRNA was expressed predominantly in the stromal keratocytes and rarely in the basal epithelial cells in normal and wounded corneas. MMP-13 mRNA was localized exclusively to basal cells of the epithelium at the wounded area from 6 hours to 3 days after wounding.
Conclusions:
MMP-14 and MMP-13 expression in rat corneas parallels that of gelatinases A and B, respectively. MMP-13 may play an important role in the gelatinase B-associated proteolytic cascade that allows rapid turnover of the extracellular matrix (ECM) components during corneal wound healing. MMP-14 may contribute to removing abnormal ECM components through activation of gelatinase A in rat corneas.
Insights
Matrix metalloproteinase-13 (MMP-13) and membrane type-1 matrix metalloproteinase (MT1-MMP; MMP-14) are expressed in rat corneas during wound healing. MMP-13 is found in wounded epithelia, while MMP-14 is in stromal cells.
Area of Science:
- Ophthalmology
- Molecular Biology
- Biochemistry
Background:
- Matrix metalloproteinases (MMPs) are crucial for extracellular matrix (ECM) remodeling.
- Several MMPs are involved in corneal wound healing processes.
- Understanding specific MMP roles aids in developing targeted therapies.
Purpose of the Study:
- To identify additional MMP gene family members in rat corneas.
- To localize the expression of membrane type-1 matrix metalloproteinase (MT1-MMP; MMP-14) and collagenase III (MMP-13) in normal and wounded rat corneas.
Main Methods:
- Laser keratectomy was performed on adult rat corneas.
- Corneas were collected at various time points post-wounding.
- Reverse transcription-polymerase chain reaction (RT-PCR), DNA sequencing, and in situ hybridization were employed.
Main Results:
- MMP-13 mRNA was detected in the epithelium of wounded corneas but not in normal corneas.
- MMP-14 mRNA was found in both normal and wounded corneas, primarily in stromal keratocytes and basal epithelial cells.
- MMP-13 mRNA localized exclusively to basal epithelial cells at the wounded site from 6 hours to 3 days post-injury.
Conclusions:
- MMP-14 and MMP-13 expression patterns in rat corneas correlate with gelatinases A and B, respectively.
- MMP-13 likely contributes to the gelatinase B-associated cascade, facilitating rapid ECM turnover during corneal healing.
- MMP-14 may aid in removing abnormal ECM components via gelatinase A activation in rat corneas.
