Abstract
Purpose:
The pathogenesis of conjunctivochalasis remains unclear. We hypothesized that gene expression profiling of conjunctival tissue from patients with conjunctivochalasis would give us an insight into the molecular pathways involved in its pathogenesis. To test this hypothesis we studied differential gene expression of conjunctivochalasis tissue compared to age-matched control conjunctival tissue with no history of ocular disease.
Methods:
Surgical specimens of conjunctivochalasis (n=4) and age-matched control conjunctival tissue (n=4) were obtained for comparison during conjunctivoplasty or strabismus surgery, respectively. Whole genome expression profiling using the Agilent human genome array slide 4x44K was performed on total RNA extracts. Differential gene expression was analyzed using GeneSpring GX 12. Genes with ≥2 fold increased or decreased expression across all four conjunctivochalasis samples were selected for further analyses. Gene ontology was determined using the PANTHER (Protein Analysis Through Evolutionary Relationships) analysis software.
Results:
A total of 1021 genes were found to be over-expressed, and 1046 genes were found to be under-expressed in all four conjunctivochalasis specimens compared to age-matched controls after excluding pseudo genes, cDNA transcripts without coded proteins, predicted proteins based on sequence homology, and genes with hypothetical or uncharacterized proteins. The protein products of the altered (over and under-expressed) genes are involved in multiple signaling pathways and biological functions including: angiogenesis; apoptosis; chemokine/cytokine-mediated inflammation; P53 signaling; and Alzheimer’s/prensilin.
Conclusions:
The gene expression profile of the conjunctivochalasis phenotype is complex. The up- and down-regulation of genes from the same pathways suggests that angiogenesis, chemokine/cytokine-mediated inflammation and apoptosis, through P53 regulation, could be important in the pathogenesis of conjunctivochalasis.
Keywords: 474 conjunctiva •
533 gene/expression