Distribution of myocilin and extracellular matrix components in the corneoscleral meshwork of human eyes.
OBJECTIVE
To examine ultrastructurally the composition of major extracellular matrix (ECM) components and the distribution of myocilin in the trabecular lamellae of corneoscleral (CS) meshwork in normal human eyes. The codistribution of myocilin with ECM components was also investigated.


METHODS
Postembedding immunoelectron microscopic studies were performed with antibodies against myocilin and other ECM components, including fibronectin, laminin, vitronectin, tenascin, elastin, fibrillin-1, microfibril-associated glycoprotein (MAGP)-1, decorin, versican, hyaluronic acid, and five types of collagen (I, III, IV, V, and VI). Double labeling of myocilin with other ECM components was performed with different sized gold particles.


RESULTS
In the trabecular beams of CS meshwork, fibronectin, laminin, and collagen type IV were associated with basement membranes, whereas elastin was specifically localized to the core of elastic-like fibers. Several types of collagens, glycoproteins, proteoglycans, and hyaluronic acid were detected both in the collagen fibers and ground substances. Myocilin predominantly localized in the long-spacing collagens and sheath materials surrounding elastic-like fibers, codistributed with fibronectin, fibrillin-1, MAGP-1, decorin, and type VI collagen.


CONCLUSIONS
This study illustrated the composition of ECM materials in the trabecular lamellae of CS meshwork. Myocilin was specifically localized to long-spacing collagens and the surrounding sheath of elastic-like fibers interacting with microfibril-associated elements where changes have been documented to occur in glaucomatous and aging eyes.
Ueda
Jun
J
Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago College of Medicine, Chicago, Illinois 60612, USA.
Yue
Beatrice Y J T
BY
D000328:Adult; D000368:Aged; D001485:Basement Membrane / Q000378:metabolism / Q000648:ultrastructure; D003315:Cornea / Q000378:metabolism* / Q000648:ultrastructure; D003598:Cytoskeletal Proteins; D016326:Extracellular Matrix Proteins / Q000378:metabolism*; D005136:Eye Proteins / Q000378:metabolism*; D006023:Glycoproteins / Q000378:metabolism*; D006801:Humans; D016253:Microscopy, Immunoelectron; D008875:Middle Aged; D012590:Sclera / Q000378:metabolism* / Q000648:ultrastructure; D014129:Trabecular Meshwork / Q000378:metabolism* / Q000648:ultrastructure; D000099179:Myocilin
D003598:Cytoskeletal Proteins; D016326:Extracellular Matrix Proteins; D005136:Eye Proteins; D006023:Glycoproteins; D000099179:Myocilin