Human amniotic epithelial cell-derived exosomes promote conjunctival goblet cells proliferation and mucin secretion

To evaluate the influence of human amniotic epithelial cell-derived exosomes (hAECs-Exo) on the proliferation, apoptosis, and cell cycle of conjunctival goblet cells in vitro. Exosomes were isolated from hAECs via ultracentrifugation and characterized using transmission electron microscopy and nanoparticle tracking analysis software. The presence of exosomal marker proteins CD63 and CD81 was confirmed through western blot. Conjunctival goblet cells were identified by morphology and immunofluorescence staining for cytokeratin 7 and mucin 5AC (MUC5AC). Subsequently, the conjunctival goblet cells were treated with hAECs-Exo or phosphate-buffered saline (control). MUC5AC expression and secretion were quantified by enzyme-linked immunosorbent assay and western blot. Cell viability, apoptosis, and cell cycle distribution were assessed using Cell Counting Kit-8 assays, Annexin V/propidium iodide staining, and flow cytometry, respectively. hAECs-Exo vesicles demonstrate positive expression for CD63 and CD81 markers. In contrast, conjunctival goblet cells exhibit fluorescent signals indicative of cytokeratin 7 and MUC5AC expression. hAECs-Exo were found to enhance the expression and secretion of MUC5AC in conjunctival goblet cells. In addition, treatment with hAECs-Exo resulted in a notable increase in the viability of conjunctival goblet cells and a reduction in apoptosis compared to treatment with phosphate-buffered saline. Following exposure to hAECs-Exo, there was a significant decrease in the proportion of G1 and G2 phase cells in conjunctival goblet cells, accompanied by a notable increase in the proportion of S-phase cells. The application of hAECs-Exo has been shown to enhance the viability of goblet cells within the conjunctival tissue and sustain their physiological activity.