Abstract
Purpose :
Corneal infections are caused by a variety of microorganisms, including bacteria, viruses, amoebae and fungi. Infectious keratitis is the 4th leading cause of blindness in the world, being represented by up to 60% by fungal keratitis in tropical countries and rural areas. In an infective process, a series of steps are taken, the first of which is the adhesion of the microorganism to the epithelium. Numerous studies have shown an intimate relationship of cell surface proteoglycans (PGs) and their glycosaminoglycans chains (GAGs) with the adhesion process in bacterial infections. The objective of this work is to determine the implication of these molecules in the adhesion of fungi to the corneal epithelium and to study the possible influence of this adhesion process in the gene expression of cell surface PGs.
Methods :
The involvement of GAGs in the adherence of Candida albicans to the corneal epithelium was studied by determining the influence of its elimination with biosynthetic inhibitors or through the use of specific bacterial lyases on the adherence of the fungus. The alterations in the transcription levels of the cell surface PGs were analyzed by RT-PCR.
Results :
The adherence of C. albicans in the form of yeast to corneal epithelial cells was limited by the elimination of cellular GAGs, showing their involvement in the process. On the contrary, when the yeast produces hyphae there was an increase in adherence. The adherence of the fungus induced significant alterations in the expression levels of the cell surface PGs, which affected both syndecans and glypicans. Within syndecans, SDC3 under-expressed with both yeast and C. albicans hyphae, while SDC4 only did so when interacting with yeast. In the case of glypicans, GPC6 showed an overexpression induced by both forms of C. albicans, while GPC1 only under-expressed induced by yeast. Furthermore, GPC3 was not expressed in corneal cells, but it did after contact with both forms of C. albicans.
Conclusions :
Corneal surface GAGs are involved in the adherence of C. albicans in the yeast form, but not in the filamented cellular forms. The interaction of the microorganism with the epithelial cells induces alterations in the transcription levels of the cell surface PGs that are dependent on the cell form presented by the fungus.
This is a 2021 ARVO Annual Meeting abstract.