title: Abnormal corneal endothelial maturation in collagen XII and XIV null mice.
abstract: OBJECTIVE
  Maturation of the endothelium and the adjacent matrix was characterized in wild-type (WT) mice. The influence of FACIT collagen XII and XIV deficiency on the morphology, maturation, and function of the corneal endothelium was examined.
  
  
  METHODS
  Analysis of the endothelium and Descemet's membrane (DM) was performed using transmission electron microscopy at postnatal day (P)4, P14, and P30 in WT, Col12a1(-/-), Col14a1(-/-), and Col12a1(-/-)/Col14a1(-/-) mice. Endothelial junctions were analyzed using ZO-1. The presence of endothelial-stromal communications was evaluated with phalloidin staining as well as electron microscopy. Finally, corneal thickness was assessed.
  
  
  RESULTS
  A thin DM, clefts between endothelial cells and DM, and large "vacuole-like" structures were present in the endothelial cells of WT mice at P4 but not noted at P30. The endothelia of Col12a1(-/-), Col14a1(-/-), and compound Col12a1(-/-)/Col14a1(-/-) in the P30 cornea maintained the vacuole-like structures seen at P4. A mature endothelial junction pattern was delayed in the null corneas. Expression of ZO-1 in WT endothelia at P14 was diffuse and localized to the basolateral and apical cell membrane. At P30, staining was localized to intercellular junctions. ZO-1 reactivity was patchy in Col12a1(-/-), Col14a1(-/-), and compound Col12a1(-/-)/Col14a1(-/-) corneas at P14 and P30. Stromal thickness was increased in P30 null corneas. Endothelial cell processes were demonstrated penetrating the DM and into the underlying stroma, throughout the entire endothelial layer in the P4 cornea.
  
  
  CONCLUSIONS
  Collagen XII and XIV null mice demonstrate delayed endothelial maturation. The structural alterations suggest functional changes in endothelial function resulting in increased corneal thickness. Endothelial-stromal interactions suggest a pathway for signal transduction.
authors.affiliation: Department of Molecular Pharmacology and Physiology, University of South Florida, Tampa, FL, USA.
authors.forename: Chinda
authors.initials: C
authors.lastname: Hemmavanh
authors.forename: Manuel
authors.initials: M
authors.lastname: Koch
authors.forename: David E
authors.initials: DE
authors.lastname: Birk
authors.forename: Edgar M
authors.initials: EM
authors.lastname: Espana
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D003094:Collagen / Q000502:physiology*; D024082:Collagen Type XII / Q000502:physiology*; D003319:Corneal Stroma / Q000378:metabolism / Q000648:ultrastructure; D003886:Descemet Membrane / Q000378:metabolism / Q000648:ultrastructure; D004728:Endothelium, Corneal / Q000378:metabolism* / Q000648:ultrastructure*; D005260:Female; D006023:Glycoproteins / Q000502:physiology*; D008297:Male; D051379:Mice; D018345:Mice, Knockout; D008855:Microscopy, Electron, Scanning; D046529:Microscopy, Electron, Transmission; D008856:Microscopy, Fluorescence; D041623:Tomography, Optical Coherence; D062826:Zonula Occludens-1 Protein / Q000378:metabolism
chemical_list: C504563:Col14a1 protein, mouse; D024082:Collagen Type XII; D006023:Glycoproteins; C569043:Tjp1 protein, mouse; D062826:Zonula Occludens-1 Protein; D003094:Collagen
keywords: FACIT collagens; collagen XII; collagen XIV; cornea; corneal endothelium; knockout mouse models; stroma