NFE2L2 activator RS9 protects against corneal epithelial cell damage in dry eye models

Abstract

Oxidative stress may cause ocular surface damage during the development of dry eye. Mammalian cells have defense systems against oxidative stress. A central regulator of the stress response is nuclear factor-erythroid 2-related factor 2 (NFE2L2). NFE2L2 is activated by the novel triterpenoid RS9 (a biotransformation compound of RTA 402). The purpose of this study was to assess the efficacy of RS9 against dry eye using in vitro and in vivo models. Bioactivity was estimated by the induction of mRNAs for two NFE2L2-targeted genes: NQO1 (prevents radical species) and GCLC (glutathione synthesis), using a corneal epithelial cell line (HCE-T). Protection against oxidation and cell damage was tested in vitro by culturing cells under hyperosmotic stress or by the addition of menadione, a generator of reactive oxygen species (ROS). Dry eye in vivo was induced by the injection of scopolamine into rats. Then, 930 nM of RS9 was applied to both eyes for 2 weeks. Oxidative stress was measured by the accumulation of 8-hydroxy-2'-deoxyguanosine (8-OHdG). Corneal wound healing was measured by scoring for superficial punctate keratitis (SPK). Corneal epithelial cell densities were evaluated histologically. RS9 and RTA 402 induced the expression of NQO1 and GCLC mRNAs in HCE-T cells. And both compounds suppressed hyperosmotic-ROS generation and menadione induced cellular damage. However RS9 had a stronger protective effect than RTA 402. Ocular instillation of RS9 also significantly upregulated the expression of Nqo1 mRNA in the corneal epithelium. Accumulation of 8-OHdG, increase of SPK scores and decrement of basal cell density were observed in corneal epithelium from scopolamine-injected rats. These changes were significantly ameliorated by the topical administration of RS9. RS9 induced Nfe2l2 activation and Nfe2l2-targeted genes, reduced oxidation, and ameliorated symptoms of dry eye using in vitro and in vivo models. Thus, RS9 might be a potent candidate agent against dry eye disease.

MicroRNA expression profile of Lacrimal Glands in rabbit autoimmune dacryoadenitis model

“…NFE2L2 has previously been reported to affect cell migration and promote the corneal epithelial wound-healing process [30]. Most recently, Matsuda et al found RS9, a novel NFE2L2 activator, can induce the expression of NFE2L2-targeted genes, including NQO1 and GCLC, and ameliorate the symptoms of dry eye, implying the important role of NFE2L2 in the development of dry eye disease [31]. With regards to the target gene of downregulated miRs, abnormal activation of P2RX7 has been revealed to participate in the development of autoimmune dry eye by inducing severe LGs dysfunction, and inhibition of P2RX7 may represent a promising therapeutic strategy for the management of autoimmune dry eye [32,33].…”

Tear miRNA expression analysis reveals miR-203 as a potential regulator of corneal epithelial cells

“…In the immortalized HCE cell line, the proliferation was promoted approximately 1.5-fold even by standard growth supplements [ 30 ], indicating the effect of miR-203 inhibitor was significant for the viability of HCE-T cells. Several studies demonstrated that the effect of the drug on the viability of HCE-T cells can be linked to the effect on the corneal wound healing [ 31 – 34 ]. Taken together, miR-203 inhibitor may have a therapeutic potential in corneal epithelial wound healing.…”

Alpha‐lipoic acid: A possible pharmacological agent for treating dry eye disease and retinopathy in diabetes

“…66 A recent study concluded that Nrf-2 activator is effective against corneal epithelial cell damage in models of dry eye. 67 Only a few studies have suggested oxidative stress as target for topical therapy of dry eye disease. 49,68 The role of oxidative stress and ALA in dry eye disease is depicted in Figure 2.…”