title: Expression of type XII collagen and hemidesmosome-associated proteins in keratoconus corneas.
abstract: OBJECTIVE
  Keratoconus is a disease characterized by thinning of the central and paracentral cornea and scarring in advanced cases. This study was performed to examine the expression of type XII collagen, proteins associated with hemidesmosomes, and beta1 integrin in keratoconus corneas.
  
  
  METHODS
  Corneal buttons were collected from normal subjects and patients with keratoconus and other corneal diseases. Immunofluorescence staining was performed on frozen sections for type XII collagen, bullous pemphigoid antigen (BP180), and integrin subunits alpha6, beta4, and beta1.
  
  
  RESULTS
  To varying degrees, all proteins examined were expressed in normal human corneas. The staining intensity of type XII collagen was diminished in keratoconus corneas in the epithelial basement membrane zone and the stromal matrix. No significant variation was found in either the staining patterns or intensities for BP180, or integrins alpha6, beta4, and beta1.
  
  
  CONCLUSIONS
  The level of type XII collagen was reduced in the epithelial basement membrane zone and stromal matrices in keratoconus corneas. These alterations may affect critical interactions of the corneal epithelium with the under-lying basement membrane, and cell-matrix interactions and matrix organization in the stroma.
authors.affiliation: Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago College of Medicine, Chicago, IL 60612, USA.
authors.forename: E L
authors.initials: EL
authors.lastname: Cheng
authors.forename: I
authors.initials: I
authors.lastname: Maruyama
authors.forename: N
authors.initials: N
authors.lastname: SundarRaj
authors.forename: J
authors.initials: J
authors.lastname: Sugar
authors.forename: R S
authors.initials: RS
authors.lastname: Feder
authors.forename: B Y
authors.initials: BY
authors.lastname: Yue
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015703:Antigens, CD / Q000378:metabolism; D001324:Autoantigens / Q000378:metabolism*; D002352:Carrier Proteins; D003094:Collagen / Q000378:metabolism*; D003315:Cornea / Q000378:metabolism* / Q000473:pathology; D003598:Cytoskeletal Proteins; D000071821:Dystonin; D019084:Fluorescent Antibody Technique, Indirect; D022002:Hemidesmosomes / Q000378:metabolism*; D006801:Humans; D039503:Integrin alpha6; D019012:Integrin beta1 / Q000378:metabolism; D039663:Integrin beta4; D016023:Integrins / Q000378:metabolism*; D007640:Keratoconus / Q000378:metabolism* / Q000473:pathology; D008856:Microscopy, Fluorescence; D008875:Middle Aged; D009419:Nerve Tissue Proteins; D024041:Non-Fibrillar Collagens; D000097805:Collagen Type XVII
chemical_list: D015703:Antigens, CD; D001324:Autoantigens; D002352:Carrier Proteins; D003094:Collagen; D003598:Cytoskeletal Proteins; D000071821:Dystonin; D039503:Integrin alpha6; D019012:Integrin beta1; D039663:Integrin beta4; D016023:Integrins; D009419:Nerve Tissue Proteins; D024041:Non-Fibrillar Collagens; D000097805:Collagen Type XVII; C486268:DST protein, human