lithium-chloride and Glaucoma

Excess scarring of the conjunctiva after glaucoma filtration surgery is a major cause of failure. Transforming growth factor (TGF)-β is critically involved in post-operative scarring. Lithium inhibits TGF-β-induced gene protein expression in corneal fibroblasts and inhibits TGF-β-induced epithelial mesenchymal transition. Here, we investigated the effects of LiCl on TGF-β1-mediated signaling pathways and on myofibroblast transdifferentiation of human Tenon's capsule fibroblasts (HTFs). LiCl treatment reduced expression of TGF-β1-induced α-SMA expression in HTFs. LiCl also decreased Akt phosphorylation induced by TGF-β1. TGF-β1-induced α-SMA expression was significantly decreased by LY294002 and Akt siRNA indicating that these changes are mediated by the PI3K/Akt pathway. Thus, LiCl induces the suppression of transdifferentiation stimulated by TGF-β1 by the regulation of PI3K/Akt signaling in HTFs.

Topics: Cell Differentiation; Cicatrix; Fibroblasts; Glaucoma; Humans; Lithium Chloride; Myofibroblasts; Phosphatidylinositol 3-Kinases; Proto-Oncogene Proteins c-akt; Signal Transduction; Tenon Capsule; Transforming Growth Factor beta

Elevated intraocular pressure (IOP) is considered as the major risk factor for the loss of retinal ganglion cells (RGCs) and their axons in glaucoma. Lithium chloride (LiCl) inhibits glycogen synthase kinase-3 beta (GSK-3β) and attends PERK-induced endoplasmic reticulum stress (ERs) transition. PERK is a type I transmembrane protein located in the endoplasmic reticulum. PERK pathway activation takes place in ERs early inhibiting protein synthnesis to protect cell and promote cell survival. Here, we firstly evaluate that LiCl reduced IOP when administered intraperitoneally. After 6 weeks, IOP dropped by around 21.9% in LiCl treated rats. Then we investigated the effects of LiCI on PERK-mediated signaling pathways. LiCl treatment activated PERK and inhibited the expression of ROCK-1 and ROCK-2 in a rat model of glaucoma. Collectively, these results suggest that LiCl reduced the IOP through the phosphorylation of PERK by the regulation of PERK/ROCK signaling in glaucoma rat model.

Topics: Activating Transcription Factor 6; Animals; eIF-2 Kinase; Endoplasmic Reticulum Stress; Glaucoma; Intraocular Pressure; Lithium Chloride; Male; Rats; Rats, Sprague-Dawley; rho-Associated Kinases; RNA, Messenger; Signal Transduction; Transcription Factor CHOP