Mechanosensitive channel inhibition attenuates TGF β2-induced actin cytoskeletal remodeling and reactivity in mouse optic nerve head astrocytes

Exp Eye Res. 2021 Oct 14:108791. doi: 10.1016/j.exer.2021.108791. Online ahead of print.ABSTRACTAstrocytes within the optic nerve head undergo actin cytoskeletal rearrangement early in glaucoma, which coincides with astrocyte reactivity and extracellular matrix (ECM) deposition. Elevated transforming growth factor beta 2 (TGFβ2) levels within astrocytes have been described in glaucoma, and TGFβ signaling induces actin cytoskeletal remodeling and ECM deposition in many tissues. A key mechanism by which astrocytes sense and respond to external stimuli is via mechanosensitive ion channels. Here, we tested the hypothesis that inhibition of mechanosensitive channels will attenuate TGFβ2-mediated optic nerve head astrocyte actin cytoskeletal remodeling, reactivity, and ECM deposition. Primary optic nerve head astrocytes were isolated from C57BL/6J mice and cell purity was confirmed by immunostaining. Astrocytes were treated with vehicle control, TGFβ2 (5 ng/ml), GsMTx4 (a mechanosensitive channel inhibitor; 500 nM), or TGFβ2 (5 ng/ml) + GsMTx4 (500 nM) for 48 h. FITC-phalloidin staining was used to assess the formation of f-actin stress fibers and to quantify the presence of crosslinked actin networks (CLANs). Cell reactivity was determined by immunostaining and immunoblotting for GFAP. Levels of fibronectin and collagen IV deposition were also quantified. Primary optic nerve head astrocytes were positive for the astrocyte marker GFAP and negative for markers for microglia (F4...

Source: Experimental Eye Research - October 17, 2021 Category: Opthalmology Authors: Alexander Kirschner Ana N Strat John Yablonski Hannah Yoo Tyler Bagu é Haiyan Li Jing Zhao Kathryn E Bollinger Samuel Herberg Preethi S Ganapathy Source Type: research