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Autophagy stimulation reduces ocular hypertension in a murine glaucoma model via autophagic degradation of mutant myocilin
Journal article   Open access   Peer reviewed

Autophagy stimulation reduces ocular hypertension in a murine glaucoma model via autophagic degradation of mutant myocilin

Ramesh B Kasetti, Prabhavathi Maddineni, Charles Kiehlbauch, Shruti Patil, Charles C Searby, Beth Levine, Val C Sheffield and Gulab S Zode
JCI insight, Vol.6(5), e143359
03/08/2021
DOI: 10.1172/jci.insight.143359
PMCID: PMC8021112
PMID: 33539326
url
https://doi.org/10.1172/jci.insight.143359View
Published (Version of record) Open Access

Abstract

Elevation of intraocular pressure (IOP) due to trabecular meshwork (TM) damage is associated with primary open-angle glaucoma (POAG). Myocilin mutations resulting in elevated IOP are the most common genetic causes of POAG. We have previously shown that mutant myocilin accumulates in the ER and induces chronic ER stress, leading to TM damage and IOP elevation. However, it is not understood how chronic ER stress leads to TM dysfunction and loss. Here, we report that mutant myocilin activated autophagy but was functionally impaired in cultured human TM cells and in a mouse model of myocilin-associated POAG ( Tg-MYOC Y437H ). Genetic and pharmacological inhibition of autophagy worsened mutant myocilin accumulation and exacerbated IOP elevation in Tg-MYOC Y437H mice. Remarkably, impaired autophagy was associated with chronic ER stress–induced transcriptional factor CHOP. Deletion of CHOP corrected impaired autophagy, enhanced recognition and degradation of mutant myocilin by autophagy, and reduced glaucoma in Tg-MYOC Y437H mice. Stimulating autophagic flux via tat-beclin 1 peptide or torin 2 promoted autophagic degradation of mutant myocilin and reduced elevated IOP in Tg-MYOC Y437H mice. Our study provides an alternate treatment strategy for myocilin-associated POAG by correcting impaired autophagy in the TM.
Ophthalmology Cell Biology Protein misfolding Cell stress Autophagy

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