Abstract
Purpose:
We have previously shown that Notch 1 has an important role in differentiation of meibomian glands as Notch 1 knockout mice leads to changes in the oil secretion which ultimately leads to the loss of glands - as reported by others. In this study we have examined the expression and activation of Notch pathway in meibomian gland epithelial cells in vitro.
Methods:
Immortalized human meibomian gland epithelial cells (IHMGEC kindly provided by Dr Sullivan) were cultured in proliferative and differentiative conditions. Cellular morphological appearance was recorded. Lipid accumulation was assessed by oil red O staining and quantified by spectrophotometry. Expression of Notch receptors and ligands were evaluated by RT-PCR and in select cases by Western blot. The effect of Notch inhibition and activation on oil production was also assessed.
Results:
IHMGEC expressed Notch1, Notch2, Notch3, Jagged1, Jagged2, Delta1 and Delta4 by RT-PCR. The protein expression of full length Notch1 and Notch3 was higher in differentiated conditions while expression of Notch2 was lower. Activation of Notch led to an increase in cell size and the amount of oil production compared to control cells.
Conclusions:
Notch signaling appears to play an important role in meibomian gland differentiation and oil production. This may provide a potential therapeutic pathway for treating meibomian gland disease.