Cytoskeletal and cell adhesion defects in wounded and Pax6+/- corneal epithelia.
OBJECTIVE
PAX6 heterozygosity (PAX6(+/-)) causes aniridia and aniridia-related keratopathy (ARK) in humans, but the pathway from gene dosage deficiency to clinical disease has not been fully characterized. Recently, the authors suggested a model of a chronic wound state exacerbated by oxidative stress, showed the barrier function of Pax6(+/-) corneas is compromised and suggested Pax6(+/-) corneas show the molecular signature of a perpetual wound-healing state.


METHODS
Pax6(+/-) mice were used as a model for Pax6-related corneal diseases and in vivo wound-healing assays. Immunohistochemistry and electron microscopy analyses were performed on mutant and wounded corneas.


RESULTS
This work reports defects in keratin, desmoplakin, and actin-based cytoskeletal structures in Pax6(+/-) cells. During wild-type corneal reepithelialization, cell fissures and desquamation, intracellular vesicles, intercellular gaps, and filopodialike structures were apparent, similar to the phenotypes seen in "unwounded" Pax6(+/-) corneal epithelia. Pax6(+/-) cells and wounded wild-type cells showed changed patterns of desmoplakin and actin localization. Protein oxidation and ERK1/2 and p38 MAPK phosphorylation were barely detected in the basal cells of intact wild-type corneal epithelia, but they were found in basal wild-type cells near the wound edge and throughout Pax6(+/-) corneal epithelia.


CONCLUSIONS
These data show that cell junctions and cytoskeleton organization are dynamically remodeled in vivo by wounding and in Pax6(+/-) corneas. This apparent wound-healing phenotype contributes to the clinical aspects of ARK.
Ou
Jingxing
J
School of Medical Sciences, University of Aberdeen, Institute of Medical Sciences, Aberdeen, United Kingdom.
Lowes
Christina
C
Collinson
J Martin
JM
D000199:Actins / Q000378:metabolism; D000818:Animals; D015783:Aniridia / Q000378:metabolism* / Q000473:pathology; D002448:Cell Adhesion / Q000502:physiology*; D002478:Cells, Cultured; D003316:Corneal Diseases / Q000378:metabolism* / Q000473:pathology; D003598:Cytoskeletal Proteins / Q000378:metabolism*; D051180:Desmoplakins / Q000378:metabolism; D019573:Epithelium, Corneal / Q000293:injuries* / Q000378:metabolism / Q000648:ultrastructure; D005131:Eye Injuries / Q000378:metabolism* / Q000473:pathology; D005136:Eye Proteins / Q000502:physiology*; D005260:Female; D018398:Homeodomain Proteins / Q000502:physiology*; D007633:Keratins / Q000378:metabolism; D008297:Male; D051379:Mice; D008808:Mice, Inbred CBA; D008855:Microscopy, Electron, Scanning; D046529:Microscopy, Electron, Transmission; D048052:Mitogen-Activated Protein Kinase 3 / Q000378:metabolism; D048053:Mitogen-Activated Protein Kinase 6 / Q000378:metabolism; D000071841:PAX6 Transcription Factor; D051761:Paired Box Transcription Factors / Q000502:physiology*; D010766:Phosphorylation; D012097:Repressor Proteins / Q000502:physiology*; D048051:p38 Mitogen-Activated Protein Kinases / Q000378:metabolism
D000199:Actins; D003598:Cytoskeletal Proteins; D051180:Desmoplakins; C495295:Dsp protein, mouse; D005136:Eye Proteins; D018398:Homeodomain Proteins; D000071841:PAX6 Transcription Factor; C000605730:PAX6 protein, human; D051761:Paired Box Transcription Factors; C000605732:Pax6 protein, mouse; D012097:Repressor Proteins; D007633:Keratins; C474633:Mapk6 protein, mouse; D048052:Mitogen-Activated Protein Kinase 3; D048053:Mitogen-Activated Protein Kinase 6; D048051:p38 Mitogen-Activated Protein Kinases