Epithelial repair: roles of extracellular matrix.
OBJECTIVE
To review studies of the roles of extracellular matrix (ECM) metabolism in corneal epithelium during wound repair. Methods. 1) Alterations in the structure and composition of epithelial basement membrane during corneal epithelial healing were examined histologically and immunohistochemically. 2) The effects of procollagen and hyaluronan synthesis inhibitors on the spread of rabbit corneal epithelium were determined in organ culture. 3) Expression of keratan sulfate proteoglycan (KSPG) proteins in corneal epithelium was examined during repair after injury in wild-type and lumican-null mice.


RESULTS
1) Corneal epithelial basement membrane was transiently degraded and reassembled during tissue repair. Patterns of type IV collagen immunoreactivity were also transiently altered. The system of matrix metalloproteinase-tissue inhibitors of metalloproteinases may play an important role in the disassembly and reorganization of epithelial basement membrane. 2) Inhibitors of procollagen secretion and hyaluronan biosynthesis disrupted the spread of a corneal epithelial sheet in situ. 3) Among the corneal KSPG proteins examined, lumican was transiently expressed in migrating murine corneal epithelial cells. Anti-lumican antibody inhibited corneal epithelial resurfacing in organ culture. The absence of lumican was found to delay corneal epithelial wound healing in mice.


CONCLUSIONS
Extracellular matrix metabolism by the injured corneal epithelium is important in the repair process.
Saika
Shizuya
S
Department of Ophthalmology, Wakayama Medical College, Japan. shizuya@wakayama-med.ac.jp
Ohnishi
Yoshitaka
Y
Ooshima
Akira
A
Liu
Chia-Yang
CY
Kao
Winston Whei-Yang
WW
D000818:Animals; D001485:Basement Membrane / Q000378:metabolism; D002465:Cell Movement; D011508:Chondroitin Sulfate Proteoglycans / Q000378:metabolism; D003094:Collagen / Q000378:metabolism; D019573:Epithelium, Corneal / Q000502:physiology*; D005109:Extracellular Matrix / Q000378:metabolism*; D016326:Extracellular Matrix Proteins / Q000378:metabolism; D006801:Humans; D006820:Hyaluronic Acid / Q000378:metabolism; D007632:Keratan Sulfate / Q000378:metabolism; D000071234:Lumican; D014945:Wound Healing / Q000502:physiology*
D011508:Chondroitin Sulfate Proteoglycans; D016326:Extracellular Matrix Proteins; C000604306:LUM protein, human; C000604307:Lum protein, mouse; D000071234:Lumican; D006820:Hyaluronic Acid; D003094:Collagen; D007632:Keratan Sulfate