Purchase this article with an account.
Wendy Kam, David Sullivan; Suppressive effects of 17β-estradiol on immortalized human meibomian gland epithelial cells. Invest. Ophthalmol. Vis. Sci. 2013;54(15):4316.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
Previous studies have shown that 17β-estradiol (E2) significantly decreases adenylate cyclase activity in bone cells, thereby attenuating the cyclic AMP response to stimulatory factors (e.g. the secretagogue forskolin). It is possible that this inhibitory effect on signal transduction represents one mechanism by which estrogens suppress sebaceous gland epithelial cell function. If so, such an E2 influence on the meibomian gland, which is a large sebaceous gland, could account for the increased incidence of dry eye disease in women taking estrogen replacement therapy. Our objective was to determine whether E2 attenuates secretagogue-induced cAMP accumulation in immortalized human meibomian gland epithelial cells (iHMGEC). As part of these studies, we also evaluated whether E2 modulates iHMGEC proliferation.
Immortalized human meibomian gland epithelial cells were cultured in medium free of serum and phenol red prior to treatment. For cAMP analysis, cells were treated with E2 (100 pM), forskolin (100 µM), the phosphodiesterase inhibitor 3-isobutyl-1-methylxanthine (IBMX; 1 mM), or buffer for 10 minutes prior to quantification of intracellular cAMP with a colorimetric enzyme-linked immunoassay. For proliferation studies, cells exposed to E2 or buffer for 1, 3, and 5 days were counted with a hemocytometer.
Estrogen treatment caused a significant decrease in secretagogue-induced cAMP accumulation in iHMGEC. This hormonal effect was observed after cellular exposure to either forskolin or IBMX. In contrast, in the absence of E2, forskolin and IBMX elicited rapid intracellular cAMP accumulation. Treatment of iHMGEC with E2 for 5 days caused a slight but significant decrease in proliferation.
Our research demonstrates that E2 may suppress both cAMP signaling in, and the proliferation of, iHMGEC. The mechanisms underlying these estrogen effects, as well as their possible role in promoting dry eye, remain to be clarified.
This PDF is available to Subscribers Only