Purpose: miRNAs can regulate inflammatory pathways. The purpose of this work was to determine if inflammatory-related tear film miRNAs are associated with extracellular vesicles (EVs) in human non-Sjögren's Syndrome dry eye disease (DED) participants.
Methods: Five DED and 5 non-DED human participants were recruited. Tears samples were collected by washing the ocular surface of both eyes with phosphate buffered saline, pooling samples from the right and left eyes, and purifying EVs from the samples with a polyethylene glycol (PEG) 8000 precipitation procedure. Samples were directly analyzed via ELISA or transmission electron microscopy (TEM), or RNA was isolated first from the EVs and evaluated with RNA-Seq.
Results: EVs were identified in the tear film of both groups using TEM and ELISA. Following EV purification and RNA isolation, RNA-Seq determined that there were 126 EV miRNAs differentially expressed between the two groups when comparing their RNA cargoes. Ingenuity Pathways Analysis found 9 upregulated miRNAs that were associated with inflammation (miR-127-5p, miR-1273h-3p, miR-1288-5p, miR-130b-5p, miR-139-3p, miR-1910-5p, miR-203b-5p, miR-22-5p, and miR-4632-3p; all p < 0.049; fold regulation range = 1.43-1.67).
Conclusion: This study determined that EVs are present in the tear film and that tear EVs contain miRNAs that may be associated with DED inflammatory pathways.
Keywords: Extracellular vesicles; RNA-Seq; dry eye disease; miRNA; tears.