Comparison of PGF2, Bimatoprost (Prostamide) and Butaprost (EP2 AGONIST) on Cyr61 and CTGF Gene Expression

Abstract

Abstract: : Purpose: Connective tissue growth factor (CTGF) and cysteine-rich angiogenic protein 61 (Cyr61) are members of the CCN gene family that encode multifunctional, extracellular matrix-associated signaling proteins. Since the mechanism of action of certain anti-glaucoma drugs involves extracellular matrix re-modeling of ocular ciliary muscle we compared three pharmacologically distinct ocular hypotensive agents on Cyr61 and CTGF gene expression. Thus, PGF_2α (FP receptor agonist), Butaprost (EP₂ receptor agonist), and Bimatoprost (a prostamide) were compared. Methods and Results: Using Affymetrix gene chip technology, we identified that prostaglandin F_2α (PGF_2α ) dramatically upregulated Cyr61 and CTGF mRNA expression in hFP-HEK 293/EBNA cells in a dose- and time-dependent manner. PGF_2α -induced upregulation of Cyr61 was exclusively Rho mediated, upregulation of CTGF was via multiple intracellular pathways. Since prostamide receptors are, to date, defined only at the pharmacological level, Bimatoprost effects on Cyr 61 and CTGF were studied in the isolated feline iris sphincter preparation, a tissue highly responsive to prostamides. Both PGF_2α and Bimatoprost upregulated Cyr61 mRNA expression whereas only PGF_2α upregulated CTGF mRNA expression in the cat iris. Therefore, PGF_2α and Bimatoprost appear to interact with different receptors populations in the cat iris, according to their markedly different effects on CTGF. Activation of prostaglandin EP₂ receptors (Gs coupled) also upregulated Cyr61 but not CTGF mRNA expression in the cat iris. Similar data were observed in human primary ciliary smooth muscle cells. Conclusions: FP receptor stimulation upregulates CTGF and Cyr 61. Whereas the prostamide analog Bimatoprost and an EP₂ agonist affected only Cyr61.

Keywords: eicosanoids • gene/expression • iris