Endothelin-induced changes of secondary messengers in cultured corneal endothelial cells.
The effect of endothelins on corneal endothelial cells is not well understood. We have investigated the effects of endothelin-1 (ET-1), endothelin-2 (ET-2) and endothelin-3 (ET-3) on bovine corneal endothelial cellular proliferation and the secondary messenger changes in cells in the presence of ET-1. It was found that the 3H-thymidine uptake was enhanced by ET-1 significantly, whereas ET-2 and ET-3 had no effect. ET-1 remarkably affects the increase of corneal endothelial cells on 3H-thymidine, 3H-leucine, and 3H-uridine uptakes in a dose-dependent manner. The 50% effective concentrations (EC50) for ET-1, as measured by 3H-thymidine uptake, 3H-uridine uptake, and 3H-leucine uptake were 10(-8.78) M, 10(-8.53) M and 10(-8.04) M, respectively. It was found that endothelin-1 increased intracellular calcium concentration by using the method of preloading with Fura-2-AM and assaying with spectrophotometry. The cellular IP1, IP2, and IP3 were also stimulated in the presence of ET-1. Moreover, ET-1 enhanced the basal cellular cAMP and cGMP concentrations in corneal endothelial cells in a dose-dependent manner. Immunofluorescent staining revealed that ET-1 increased the fibronectin protein concentration and changed protein distribution in corneal endothelial cells. These findings indicate that endothelin-1 increases in cell proliferation and biological changes may be involved in changing intracellular calcium mobility, increasing intracellular phosphoinositides, enhancing intracellular cGMP and cAMP accumulation, and fibronectin protein synthesis.
Wu
K Y
KY
Department of Ophthalmology, Kaohsiung Medical University, Taiwan, Republic of China.
Hong
S J
SJ
Lin
C P
CP
Lai
Y H
YH
Wang
H Z
HZ
D000818:Animals; D002118:Calcium / Q000378:metabolism; D002417:Cattle; D002455:Cell Division / Q000187:drug effects; D002478:Cells, Cultured; D000242:Cyclic AMP / Q000378:metabolism; D006152:Cyclic GMP / Q000378:metabolism; D004261:DNA Replication; D004305:Dose-Response Relationship, Drug; D019332:Endothelin-1 / Q000494:pharmacology*; D004728:Endothelium, Corneal / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D005353:Fibronectins / Q000378:metabolism; D016257:Fura-2 / Q000031:analogs & derivatives* / Q000378:metabolism; D007295:Inositol Phosphates / Q000378:metabolism; D007930:Leucine / Q000378:metabolism; D015290:Second Messenger Systems / Q000502:physiology; D013936:Thymidine / Q000378:metabolism; D014529:Uridine / Q000378:metabolism
D019332:Endothelin-1; D005353:Fibronectins; D007295:Inositol Phosphates; C049925:fura-2-am; D000242:Cyclic AMP; D007930:Leucine; D006152:Cyclic GMP; D002118:Calcium; D016257:Fura-2; D013936:Thymidine; D014529:Uridine