Abstract
Purpose :
Chemokines CCL28, CXCL14, and CXCL17 have important roles in mucosal immunity under inflammatory conditions. In this study, we evaluated their expression in conjunctival cells from dry eye (DE) patients and in an in vitro model of DE.
Methods :
We included 21 DE patients and 12 healthy subjects. The inclusion criteria for DE were: ocular surface disease index score ≥13 and at least 2 of the following in both eyes: tear break-up time ≤7 sec, corneal or conjunctival staining ≥1 (Oxford scale), and Schirmer test ≤5 mm. Dendritic cells and subbasal nerve plexus were analyzed in central corneal by in vivo confocal microscopy. Conjunctival epithelial cells were collected by impression cytology. For the DE in vitro approach, Human Conjunctival Epithelial Cells (IM-HConEpiC, Innoprot) were cultured under 4 osmolarities (300, 400, 450 and 500 mOsM) or under inflammatory conditions (TNF-α 25ng/ml) for 24h. Then, Human Conjunctival Fibroblasts (HConF, Innoprot) were stimulated for 24h with the secretome from IM-HConEpiC cultured under 500 mOsM or TNF-α. CCL28, CXCL14 and CXCL17 gene expression was analyzed by qPCR. CCL28 and CXCL14 secretion was quantified by multiplex immunobead-based assay and CXCL17 by ELISA. Differences in gene expression levels, cytokine secretion, and their correlations with clinical parameters were statistically analyzed.
Results :
Conjunctival cells from DE patients showed an upregulation (p<0.05) of CCL28 gene expression; CCL28 levels positively correlated with corneal staining (p<0.05), dendritic cell density (p<0.05), and CXCL17 gene expression (p<0.001), and negatively correlated with tear stability (p<0.05) and corneal nerve density (p<0.05). IM-HConEpiC cells cultured under hyperosmolar conditions had increased CCL28 (p<0.01), CXCL14 (p<0.05) and CXCL17 (p<0.05) secretion, whereas cells stimulated with TNF-α increased CXCL17 secretion (p>0.05). The secretome from IM-HConEpiC cultured under hyperosmolar or inflammatory conditions increased CCL28 secretion in HConF (p<0.05).
Conclusions :
The results suggest that CCL28, CXCL14, and CXCL17 play a role in in vitro-simulated DE. Moreover, this is the first report that analyses their gene expression in conjunctival epithelial cells from DE patients. Given its chemotactic, immunomodulatory and antimicrobial activities, CCL28 might play an important role in DE.
This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.