Purpose: To analyze the changes in the lacrimal gland (LG) miRNAome from male nonobese diabetic (NOD) mice with autoimmune dacryoadenitis compared with LG from healthy male BALB/c and dacryoadenitis-free female NOD mice.
Methods: LG from these mice were collected for small RNA sequencing to identify dysregulated miRNAs; hits were validated by RT-qPCR in male NOD and BALB/c LG. Dysregulation of validated species within immune cell-enriched cell fractions and epithelial-enriched cell fractions from LG was probed by RT-qPCR. Ingenuity pathway analysis identified putative miRNA targets, which were examined in publicly available mRNA-seq datasets. Western blotting and confocal imaging of immunofluorescence enabled validation of some molecular changes at the protein level.
Results: Male NOD LG exhibited 15 and 13 significantly up- and downregulated miRNAs, respectively. Dysregulated expression of 14 of these miRNAs (9 upregulated, 5 downregulated) was validated in male NOD versus BALB/c LG by RT-qPCR. Seven of the upregulated miRNAs were increased owing to their abundance in immune cell-enriched cell fractions, whereas four downregulated miRNAs were largely expressed in epithelial-enriched cell fractions. Ingenuity pathway analysis predicted the upregulation of IL-6 and IL-6-like pathways as an outcome of miRNA dysregulation. Increased expression of several genes in these pathways was confirmed by mRNA-seq analysis, whereas immunoblotting and immunofluorescence confirmed Ingenuity pathway analysis-predicted changes for IL-6Rα and gp130/IL-6st.
Conclusions: Male NOD mouse LG exhibit multiple dysregulated miRNAs owing to the presence of infiltrating immune cells, and decreased acinar cell content. The observed dysregulation may increase IL-6Rα and gp130/IL-6st on acini and IL-6Rα on specific lymphocytes, enhancing IL-6 and IL-6-like cytokine signaling.