Unravelling Novel Roles of Salivary Exosomes in the Regulation of Human Corneal Stromal Cell Migration and Wound Healing

Abstract

Salivary exosomes have demonstrated vast therapeutic and diagnostic potential in numerous diseases. This study pioneers previously unexplored roles of SE in the context of corneal wound healing by utilizing primary corneal stromal cells from healthy (HCFs), type I diabetes mellitus (T1DMs), type II DM (T2DMs), and keratoconus (HKCs) subjects. Purified, healthy human SEs carrying tetraspanins CD9+, CD63+, and CD81+ were utilized. Scratch and cell migration assays were performed after 0, 6, 12, 24, and 48 h following SE stimulation (5 and 25 µg/mL). Significantly slower wound closure was observed at 6 and 12 h in HCFs with 5 μg/mL SE and T1DMs with 5 and 25 μg/mL SE. All wounds were closed by 24-hour, post-wounding. HKCs, T1DMs, and T2DMs with 25µg/mL SE exhibited a significant upregulation of cleaved vimentin compared to controls. Thrombospondin 1 was significantly upregulated in HCFs, HKCs, and T2DMs with 25 µg/mL SE. Lastly, HKCs, T1DMs, and T2DMs exhibited a significant downregulation of fibronectin with 25 μg/mL SE. Whether SEs can be utilized to clinical settings in restoring corneal defects is unknown. This is the first-ever study exploring the role of SEs in corneal wound healing. While the sample size was small, results are highly novel and provide a strong foundation for future studies.

Impact of Exosomes Released by Different Corneal Cell Types on the Wound Healing Properties of Human Corneal Epithelial Cells

“…Moreover, EVs have been found to be secreted in the cornea following wounding [ 41 ] and it is known that exosomes secreted by corneal epithelial cells can pass through the BM if impaired by an injury [ 41 ]. These results all pointed to a potential role of exosomes in corneal wound healing, which has recently been the focus of a few studies [ 41 , 42 , 45 , 46 , 47 , 48 ]. However, characteristics, functional roles and mechanisms of action of corneal exosomes remain to be fully investigated.…”

Promising applications of human-derived saliva biomarker testing in clinical diagnostics

“…257 Additionally, neurodegenerative diseases were given much attention for saliva exosome biomarker discovery. 258 There have been reviews summarizing salivary exosomal biomarkers in cancer, [259][260][261][262][263] neurodegenerative diseases, 264 mental diseases, 265 systematic disease, 266 wound healing 267,268 and isolation methods. 269,270 Research articles emphasize protein biomarkers 250,257,[271][272][273][274][275] and RNA markers.…”

“…There have been reviews summarizing salivary exosomal biomarkers in cancer, 259 – 263 neurodegenerative diseases, 264 mental diseases, 265 systematic disease, 266 wound healing 267 , 268 and isolation methods. 269 , 270 Research articles emphasize protein biomarkers 250 , 257 , 271 – 275 and RNA markers.…”

Research Progress of Bioinspired Nanostructured Systems for the Treatment of Ocular Disorders

“…Widyaningrum et al [ 96 ] found that the platelet extracellular vesicles (PEVs) could increase the viability, wound-healing rate, as well as the proliferation markers of corneal endothelial cells, which represents a novel regenerative biotherapy for corneal endothelial dysfunction. The healthy human exosomes were also found to positively regulate the migration of human corneal stromal cell and wound healing in a recent study by Escandon et al [ 97 ]. The studies summarized above clearly support the tremendous potential of EVs for regenerative medicine applications; however, further investigations in animals still need to be carried out for clinical translation.…”