Abstract
Purpose :
Intraocular pressure is set by resistance generation to aqueous humor outflow in the juxtacanicular region where trabecular meshwork (TM) and Schlemm’s canal (SC) cells interact. Elements of the renin-angiotensin system (RAS) may contribute to outflow resistance since modulation of some RAS enzymes decrease IOP in experimental glaucoma. Our objective is to examine the expression of the (pro)renin receptor (PRR) and evaluate the effects of renin on signaling in and protein expression by cultured human SC cells.
Methods :
RNA isolated from two human SC and three TM cells strains at confluence was tested using RT-PCR for expression of renin and PRR. In parallel, one SC cell strain was treated with renin (10-6, 10-7, and 10-8M) in 1% FBS-low glucose DMEM for 48 h and fibronectin content in conditioned media was analyzed by Western blot. Beta-catenin localization in cells was assessed by immunofluorescence microscopy.
Results :
PRR, but not renin, was expressed in both SC and TM cells strains. Immunofluorescence analysis showed predominantly a cytoplasmatic and plasma membrane distribution of beta-catenin in untreated SC cells, while beta-catenin translocated to nucleus in 53% of renin-treated cells. In a biphasic dose-dependent fashion, renin increased fibronectin secretion from SC cells. Renin also appeared to cause morphological alterations that needs to be characterized further.
Conclusions :
Cultured human SC cells appear not to express renin, but have a functional system for responding to renin in the aqueous humor. Its role in resistance generation needs to be explored in future studies.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.