Purchase this article with an account.
Ariana Allen, Rupalatha Maddala, Ponugoti Vasantha Rao; Role of Mechanosensitive Piezo Ion Channels in Ocular Lens Architecture and Function. Invest. Ophthalmol. Vis. Sci. 2020;61(7):1096.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
To determine the expression, distribution, and role of Piezo channels the ocular lens
Expression and distribution of Piezo channels in developing and mature mouse lenses was analyzed by RT-PCR, RNA-seq, immunoblot and immunofluorescence analyses in wild type (C57BL/6J) and transgenic Piezo1-tdT (obtained from the Jax laboratory) mouse lenses. To test the functional significance of Piezo channel activity in the lens, Piezo1 agonist (Yoda1) and antagonist (GsMTx4) were used in the organ-cultured mouse lenses in conjunction with histological, biochemical and biomechanical analyses.
Both Piezo 1 and Piezo 2 channels are expressed in the mouse lens, with Piezo 1 having a relatively higher expression and distributing to both epithelium and fiber cells. Pharmacological activation of Piezo1 in organ-cultured P30 mouse lenses by Yoda1 for one hour showed a significant (by 66%; n=4) increase in the level of phosphorylated myosin light chain (MLC) with no change in total MLC, suggesting an increased calcium influx due to Piezo1 activation leading to MLC phosphorylation. Yoda1 treatment for an extended period (24 hrs) led to cataract development in association with degradation of lens membrane proteins. On the other hand, inhibition of Piezo1 by GsMTx4 for 48 hours demonstrated a significant (by 70%; n=6) decrease in MLC phosphorylation with no change in either total MLC or β-actin levels in P30 mouse lenses compared to controls. Piezo1 inhibition had no significant influence on lens tensile properties. Additionally, the membrane organization and stability of Piezo1 in the lens was found to be regulated by ankyrin-B, a well-recognized membrane scaffolding protein.
This study reveals expression and distribution of Piezo mechanosensitive channels in mouse lens epithelium and fibers and a role for Piezo1 channel activity in regulation of calcium-dependent MLC phosphorylation, a critical regulator of contractile activity. Importantly, loss of lens transparency associated with dysregulation of Piezo1 channel activity appears to result from an augmentation of calcium-dependent calpain activity leading to degradation of lens membrane proteins. Collectively, this study reveals the physiological significance of Piezo channel activity in lens calcium signaling and function.
This is a 2020 ARVO Annual Meeting abstract.
This PDF is available to Subscribers Only