Publications by authors named "April Nettesheim"

Glaucoma encompasses a spectrum of disorders characterized by the chronic degeneration of retinal ganglion cell (RGC) axons and the progressive loss of RGCs, resulting in visual impairment. In this study, we investigated the effect of autophagy deficiency on two glaucoma hypertensive models, the DBA/2J spontaneous glaucoma model, and the TGFβ2 (transforming growth factor β2) chronic ocular hypertensive model. For this, we used the and DBA/2J- mice, this latter generated in our laboratory via CRISPR/Cas9 technology, which display impaired autophagy.

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Article Synopsis
  • - The Schlemm's canal (SC) is a vessel in the eye that helps regulate fluid drainage, impacting intraocular pressure; shear stress from fluid flow affects how SC cells behave.
  • - Researchers discovered that shear stress activates autophagy in SC cells through the primary cilium (PC), with an important role played by phosphorylated SMAD2, which also activates certain signaling pathways.
  • - Interestingly, while autophagy is usually inhibited by the mTOR pathway, shear stress activates mTOR in SC cells, indicating a complex relationship between the PI3K and SMAD2/3 pathways in regulating autophagy in response to fluid flow.
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Glaucoma is a group of diseases that leads to chronic degeneration of retinal ganglion cell (RGC) axons and progressive loss of RGCs, resulting in vision loss. While aging and elevated intraocular pressure (IOP) have been identified as the main contributing factors to glaucoma, the molecular mechanisms and signaling pathways triggering RGC death and axonal degeneration are not fully understood. Previous studies in our laboratory found that overactivation of autophagy in DBA/2J::GFP-LC3 mice led to RGC death and optic nerve degeneration with glaucomatous IOP elevation.

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Activation of autophagy is one of the responses elicited by high intraocular pressure (IOP) and mechanical stretch in trabecular meshwork (TM) cells. However, the mechanosensor and the molecular mechanisms by which autophagy is induced by mechanical stretch in these or other cell types is largely unknown. Here, we have investigated the mechanosensor and downstream signaling pathway that regulate cyclic mechanical stretch (CMS)-induced autophagy in TM cells.

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Extracellular matrix (ECM) deposition in the trabecular meshwork (TM) is one of the hallmarks of glaucoma, a group of human diseases and leading cause of permanent blindness. The molecular mechanisms underlying ECM deposition in the glaucomatous TM are not known, but it is presumed to be a consequence of excessive synthesis of ECM components, decreased proteolytic degradation, or both. Targeting ECM deposition might represent a therapeutic approach to restore outflow facility in glaucoma.

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Purpose: To investigate autophagy in the outflow pathway and ganglion cell layer in the aging and ocular hypertensive mouse.

Methods: Both 4-month-old and 18-month-old C57BL/6J and GFP-LC3 mice were subjected to unilateral injection of hypertonic saline into a limbal vein, causing sclerosis of the outflow pathway and subsequent elevation of intraocular pressure (IOP). IOP was measured on a weekly basis using a rebound tonometer.

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The trabecular meshwork (TM) is a specialized ocular tissue, which is responsible, together with the Schlemm's canal (SC), for maintaining appropriate levels of intraocular pressure. Dysfunction of these tissues leads to ocular hypertension and increases the risk for developing glaucoma. Previous work by our laboratory revealed dysregulated autophagy in aging and in glaucomatous TM cells.

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Unlabelled: The trabecular meshwork (TM) is a key regulatory tissue of intraocular pressure (IOP) in the anterior chamber of eye. Dysfunction of the TM causes resistance to outflow of aqueous humor, which in turn leads to elevated IOP, a main risk factor of glaucomatous neurodegeneration. Due to variations in IOP, TM cells are continuously exposed to mechanical deformations.

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