Induction of angiogenic immediate early genes by activation of FP prostanoid receptors in cultured human ciliary smooth muscle cells.
OBJECTIVE
Agonists of the F prostanoid receptor for prostaglandin F2alpha exert. exert an ocular hypotensive effect that has been attributed to increased aqueous humor outflow through the uveoscleral pathway. Although tissue remodeling of the ciliary muscle has been described, the signaling mechanisms that link activation of the FP receptor to remodeling of the ciliary muscle are poorly understood. Herein, we describe the identification of novel signaling mechanisms that may contribute to this process.


METHODS
Cultures of human ciliary smooth muscle cells were established from fetal eye tissue explants. The cells were validated by their expression of alpha-smooth muscle-actin and functional FP receptors. Cultures were treated with prostaglandin F(2 alpha) and examined for the induction of three immediate early genes related to tissue remodeling using Western blot analysis, quantitative real-time polymerase chain reaction, and reporter gene assays.


RESULTS
Human ciliary smooth muscle cells express functional FP receptors whose activation up-regulates the expression of early growth response factor-1 and connective tissue growth factor at the mRNA and protein levels. Prostaglandin F(2 alpha) stimulation also increases the protein expression of hypoxia-inducible factor-1 alpha and activates luciferase reporter plasmids under the control of the hypoxia response element.


CONCLUSIONS
Early growth response factor-1 and hypoxia-inducible factor-1 alpha are important transcriptional activators of downstream genes involved in tissue remodeling and angiogenesis, whereas connective tissue growth factor is a secreted growth factor that also contributes to these processes. Thus, stimulation of FP receptors in human ciliary smooth muscle cells up-regulates the expression of immediate early genes that may coordinate the remodeling of the ciliary muscle, thereby facilitating aqueous outflow.
Hutchinson
Anthony J
AJ
Program in Neuroscience, University of Arizona, Tucson, Arizona 85721, USA.
Coons
Serena C
SC
Chou
Chih-Ling
CL
Xu
Wei
W
Stamer
W Daniel
WD
Woodward
David F
DF
Regan
John W
JW
D000199:Actins / Q000378:metabolism; D015153:Blotting, Western; D002478:Cells, Cultured; D002924:Ciliary Body / Q000187:drug effects* / Q000196:embryology / Q000378:metabolism; D055513:Connective Tissue Growth Factor / Q000235:genetics; D015237:Dinoprost / Q000494:pharmacology*; D051766:Early Growth Response Protein 1 / Q000235:genetics*; D019084:Fluorescent Antibody Technique, Indirect; D005786:Gene Expression Regulation / Q000187:drug effects; D017781:Genes, Immediate-Early / Q000502:physiology; D006801:Humans; D051795:Hypoxia-Inducible Factor 1, alpha Subunit / Q000378:metabolism*; D007295:Inositol Phosphates / Q000378:metabolism; D009130:Muscle, Smooth / Q000187:drug effects* / Q000196:embryology / Q000378:metabolism; D018919:Neovascularization, Physiologic; D012333:RNA, Messenger / Q000378:metabolism; D011982:Receptors, Prostaglandin / Q000235:genetics / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction
C541116:ACTA2 protein, human; D000199:Actins; D051766:Early Growth Response Protein 1; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D007295:Inositol Phosphates; D012333:RNA, Messenger; D011982:Receptors, Prostaglandin; C034671:prostaglandin F2alpha receptor; D055513:Connective Tissue Growth Factor; D015237:Dinoprost