Abstract
Purpose :
Corneal epithelial stem cells (CESCs) residing in the limbus regions regenerate epithelial cells during homeostasis and wound healing, making them indispensable in treating ocular surface damages caused by ocular diseases. Caveolin1 (Cav1) is expressed in the basal limbal region of the corneas of mice and humans, but little or no expression in the healthy corneal epithelium. Little is known about the role cav1 plays in the maintenance of CESCs. We hypothesize that loss of function of cav1 in the limbal region expands the CESC population and/or the cell cycle kinetics and thus contributing to accelerated wound healing.
Methods :
To determine if global cav1 KO (knock-out) mice have expanded stem cell population, we quantify the width of the limbus in corneal sections and whole mounts. We demarcate the limbus using anatomic features and keratin specific antibodies: anti-K14, (labeling undifferentiated cells), and anti-K12 (differentiating cells). To determine if cav1 has a role in the proliferation of limbal cells, we inject thymidine analogue EdU (5-Ethynyl-2’-deoxyuridine) in WT (wild type) and cav1 KO mice. With different duration of pulse and chase combinations, we can determine if Cav1 affects cell cycle kinetics of these cells.
Results :
We confirmed that anti-K14 labeled undifferentiated cells in the basal limbal region while anti-K12 labeled differentiating and differentiated cells in the corneal epithelium. Whole mount mean values for 6 month-old WT (n=5, SD±185.9) were 298.5mm, 350.3mm for heterozygotes (KW) (n=7, SD±73.5), and 377.5mm (n=3, SD±57.79) for KO. The mean difference between either KO and KW or KO and WT was not statistically significant. Tissue section mean values for 16-18 month old mice were 381mm (n=7, SD± 40) for KW and 392mm (n=5, SD±18) for KO mice. No significant difference was found between KW and KO groups.
Conclusions :
Tissue section and whole mount measurements of limbal width varied among WT, KW, and KO groups. However, these biological differences did not reach statistical significance. We will complete measurements for additional age groups to confirm our findings that the limbal width of cav1 KO mice was not expanded compared to WT and KW mice. EdU pulse/chase experiments will reveal if Cav1 plays a role in cell cycle kinetics. With this information, we might better understand the role of Cav1 in CESCs during homeostasis,
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.