September 2016
Volume 57, Issue 12
Open Access
ARVO Annual Meeting Abstract  |   September 2016
MECHANICAL STRETCH ALTERS THE EXPRESSION PROFILE OF MECHANOSENSITIVE CHANNELS IN MOUSE RETINAL GANGLION CELLS VIA ACTIVATION OF TRPV4
Author Affiliations & Notes
  • Tam Thi Thanh Phuong
    Department of Ophthalmology and Visual Sciences, University of Utah School of Medicine, John A. Moran Eye Institute, Salt Lake City, Utah, United States
  • Monika Lakk
    Department of Ophthalmology and Visual Sciences, University of Utah School of Medicine, John A. Moran Eye Institute, Salt Lake City, Utah, United States
  • David Krizaj
    Department of Ophthalmology and Visual Sciences, University of Utah School of Medicine, John A. Moran Eye Institute, Salt Lake City, Utah, United States
    Department of Neurobiology and Anatomy, University of Utah School of Medicine, John A. Moran Eye Institute, Salt Lake City, Utah, United States
  • Footnotes
    Commercial Relationships   Tam Phuong, None; Monika Lakk, None; David Krizaj, None
  • Footnotes
    Support  None
Investigative Ophthalmology & Visual Science September 2016, Vol.57, 4800. doi:
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      Tam Thi Thanh Phuong, Monika Lakk, David Krizaj; MECHANICAL STRETCH ALTERS THE EXPRESSION PROFILE OF MECHANOSENSITIVE CHANNELS IN MOUSE RETINAL GANGLION CELLS VIA ACTIVATION OF TRPV4. Invest. Ophthalmol. Vis. Sci. 2016;57(12):4800.

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      © ARVO (1962-2015); The Authors (2016-present)

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Abstract

Purpose : It has been suggested that Trpv4, a putative mechanosensitive cation-permeable channel contributes to pressure-dependent cellular remodeling and loss of retinal ganglion cells (RGCs). However, the molecular mechanisms linking mechanical stress to phenotype changes and degeneration of RGCs are not known. In this study, we used novel uniaxial and biaxial mechanical stress paradigms to determine whether strain affects the expression profile of putative mechanosensitive channels in RGCs.

Methods : RGCs were purified from retinas of C57BL/6 pups using two-step immunopanning. Cells were cultured for 1-2 weeks in a defined medium and plated onto silicon membranes for uni- or biaxial stretch experiment. qRT-PCR was applied to determine transcript levels of putative mechanosensitive ion channels. Calcium imaging was used to measure the dynamics of intracellular calcium in response to selective TRP channel agonists.

Results : Purified cultured RGCs expressed transcripts encoding Trpv4 and other putative mechanosensitive channels such as Trpv1, Trpa1, Piezo1, and Piezo2. Application of biaxial stretch for 3hrs significantly upregulated mRNA for Trpv1 (1.7-fold), Trpv4 (1.36-fold), Trpa1 (10-fold), Piezo1 (1.23-fold), and Piezo2 (2.5-fold). The upregulation of the genes encoding these channels was markedly attenuated by pharmacological inhibition of Trpv4 channels. The functionality of Trpv4 in immunopanned cell cultures was validated in cells loaded with calcium indicator dyes, which responded to the selective Trpv4 agonist GSK1016790A and glutamate with substantial [Ca2+]i elevations.

Conclusions : Our results suggest that mechanical stretch regulates Trpv4- and Ca2+- dependent expression of putative mechanosensitive channels in RGCs. These results directly link increases in intraocular pressure (IOP) that occur in hypertensive glaucoma to mechanotransduction and gene expression changes in RGCs, thereby identifying a novel potential neuroprotection target for debilitating blinding disease.

This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.

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