Abstract
Purpose :
Transient receptor potential channels (TRP-channels) are cation channels with ubiquitous expression. They are thought to have a role in the secretion mechanism of exocrine glands. Moreover, they have been shown to be involved in inflammatory processes at the ocular surface. So far, the impact of TRP-channels with regard to the development of the lacrimal gland is unclear. Based on pilot investigations, we hypothesize that TRPM3 might play a role in the development and function of the lacrimal gland. Therefore, we analyzed the expression of TRPM3 in different embryonic and postembryonic lacrimal glands with and without light exposure.
Methods :
Lacrimal glands from mice of different developmental stages (0, 2, 4, 6, 7 and 14 days old, N=4 for 0, 4 and 7 days, N=3 for 2, 6 and 14 days old mice) that were kept in the darkness and under normal light conditions (prenatal 16 and 18, 0, 2, 4, 6 ,7, 10, 20 days, 4 weeks, 6 months, 1 year and 2 years old, N=4 for prenatal 16 and 18, 0, 4, 7, 10, 20 days, 8 weeks, 6 months 1 and 2 years old mice, N=3 for 2 and 6 days old mice) were processed for RT-PCR and immunohistochemistry. In addition, primary lacrimal gland epithelial (LGE) and mesenchymal cells (LGM) from newborn mice were cultivated separately or co-cultured (N=4 for each culture). After RNA extraction TaqMan real-time PCR-assays were performed to quantify TRPM3 gene expression. Two-tailed Student's t-test was used for statistical analysis.
Results :
TRPM3 gene expression relatively increased from day 16 of embryonic stage to birth. After birth, TRPM3 gene expression significantly decreased with increasing age up until 2 years old mice. The relative TRPM3 gene expression in LGE cells was significantly higher than that of LGM cells. Immunohistochemical analysis revealed a membranous, luminal expression of TRPM3 in the excretory ducts as well as in the acini of younger mice. Newborn and 4 days old mice kept in the darkness show a up to two-times lower TRPM3 gene expression compared to mice kept under normal light conditions.
Conclusions :
Our results indicate developmental changes in the TRPM3 gene expression of murine lacrimal gland as well as a possible influence through light exposure. This supports our hypothesis that TRPM3 is involved in lacrimal gland development in late embryonic stages of mouse lacrimal gland.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.