Abstract
Purpose: :
Chronic oxidative stress and the resulting induction of cellular senescence are associated with changes in expression of multiple microRNAs (miRNAs). However, little is known about the consequences of these miRNA expression changes on cellular functions relevant to the maintenance of normal levels of aqueous humor (AH) outflow such as the regulation of actomyosin-mediated cell contraction. Therefore, we investigated the potential role of three miRNAs (miR-155, miR-200c, and miR-204) on the regulation of cell contraction in trabecular meshwork cells.
Methods: :
Changes in gene expression induced by miR-155, miR-200c, miR-204 in human trabecular meshwork (HTM) cells were evaluated by gene array analysis and confirmed by real time Q-PCR. Effects on cell contraction were measured using a three-dimensional collagen gel (1.5 mg/mL COLA1A) contraction assay.
Results: :
Serum-induced contraction of HTM cells was significantly (p<0.05) inhibited by miR-155 (38% SD= 2.7), miR-200c (44% SD= 6.5); and miR-204 (24% SD= 4.2). These miRNAs down-regulated several predicted target genes that could contribute to the observed inhibitory effects on cell contraction. MiR-155 inhibited the expression of myosin X (MYO10), myosin ID (MYO1D), and myosin light chain kinase (MYLK); miR-200c inhibited the endothelin receptor type A (EDNRA), formin homology 2 domain containing 1 (FHOD1), and the lysophosphatidic acid receptor 1 (LPAR1); and miR-204 inhibited multiple genes involved in inflammation, including interleukin 1 beta (IL1B) and interleukin 8 (IL8), as well as the regulation of beta-catenin signaling Transcription factor 4 (TCF4).
Conclusions: :
miRNAs miR-155, miR-200c, and miR-204 exert inhibitory effects on cell contraction in HTM cells that appear to be mediated through of multiple gene targets. Since inhibition of actomyosin-mediated cell contraction is known to increase AH outflow facility, these miRNAs might constitute novel therapeutic targets for the management of elevated IOP in glaucoma.
Keywords: trabecular meshwork • cytoskeleton • gene/expression