Phenotypic and Functional Alterations in Tunneling Nanotubes Formed by Glaucomatous Trabecular Meshwork Cells

The actin cytoskeleton of trabecular meshwork (TM) cells is a therapeutic target for lowering intraocular pressure (IOP) in glaucoma patients. Netarsudil (the active ingredient in RhopressaTM) is a Rho-associated protein kinase inhibitor that induces disassembly of actin stress fibers. Here, we used live cell imaging of SiR-actin-labeled normal (NTM) and glaucomatous TM (GTM) cells to investigate actin dynamics during actin-driven biological processes with and without netarsudil treatment. Actin stress fibers were thicker in GTM than NTM cells and took longer (>120 min) to disassemble following addition of 1 µM netarsudil. Actin-rich extracellular vesicles (EVs) were derived by two mechanisms: exocytosis of intracellular-derived vesicles, and cleavage of filopodial tips, which detached the filopodia from the substratum, allowing them to retract to the cell body. While some phagocytosis was noted in untreated TM cells, netarsudil potently stimulated phagocytic uptake of EVs. Netarsudil treatment induced lateral fusion of tunneling nanotubes (TNTs) that connected adjacent TM cells; TNTs are important for TM cellular communication. Together, our results suggest that netarsudil may clear outflow channels in TM tissue by inducing phagocytosis and/or by modulating TM communication via EVs and TNTs. These cellular functions likely work together to regulate IOP in normal and glaucomatous TM.

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Trabecular Meshwork Stem Cells Could Be Differentiated to Be Trabecular Meshwork Cells with Secretory Functions

SSRN Electronic Journal ◽

10.2139/ssrn.3421588 ◽

2019 ◽

Author(s):

Ying Su ◽

Xin Jiang ◽

Elizabeth (Xiaomeng) Wang ◽

Feng Wang ◽

Ying Han

Keyword(s):

Stem Cells ◽

Trabecular Meshwork ◽

Trabecular Meshwork Cells

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Mechanical stretch upregulates connexin43 in human trabecular meshwork cells

Clinical and Experimental Ophthalmology ◽

10.1111/ceo.13492 ◽

2019 ◽

Cited By ~ 2

Author(s):

Nikoleta Tellios ◽

Mary Feng ◽

Nancy Chen ◽

Hong Liu ◽

Vasiliki Tellios ◽

...

Keyword(s):

Trabecular Meshwork ◽

Mechanical Stretch ◽

Trabecular Meshwork Cells

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Effect of dexamethasone on the expression of MMPs, adenosine A1 receptors and NFKB by human trabecular meshwork cells

Journal of Basic and Clinical Physiology and Pharmacology ◽

10.1515/jbcpp-2019-0373 ◽

2020 ◽

Vol 0 (0) ◽

Cited By ~ 1

Author(s):

Normie Aida Mohd Nasir ◽

Renu Agarwal ◽

Anna Krasilnikova ◽

Siti Hamimah Sheikh Abdul Kadir ◽

Igor Iezhitsa

Keyword(s):

Extracellular Matrix ◽

Western Blot ◽

Trabecular Meshwork ◽

Culture Media ◽

Smooth Muscle Actin ◽

Adenosine A1 Receptors ◽

Trabecular Meshwork Cells ◽

Aqueous Humor Dynamics ◽

Nfkb Activation ◽

Adenosine A1

AbstractObjectivesSteroid-induced ocular hypertension and glaucoma are associated with extracellular matrix remodeling at the trabecular meshwork (TM) of the eye due to reduced secretion of matrix metalloproteinases (MMPs), a family of enzymes regulating extracellular matrix proteolysis. Several biological functions of steroids are known to involve regulation of adenosine A1 receptors (A1AR) and nuclear factor kappa B (NFKB). Since MMPs expression in TM has been shown to be regulated by A1AR as well as transcription factors, it is likely that dexamethasone-induced changes in aqueous humor dynamics involve reduced MMP and A1AR expression and reduced NFKB activation. Hence, the current study investigated the association of dexamethasone-induced reduction in MMP secretion with reduced NFKB activation and A1AR expression.MethodsHuman trabecular meshwork cells (HTMCs) were characterized by estimating myocilin and alpha smooth muscle actin expression and then were treated with dexamethasone 100 nM for 2, 5 and 7 days. The MMP secretion was estimated in culture media using Western blot. Immunocytochemistry (ICC) and ELISA were done to investigate the effect of dexamethasone on NFKB phosphorylation. A1AR expression in HTMCs was determined using Western blot and ELISA.ResultsDexamethasone caused a significant reduction in both MMP-2 and -9 expression compared to untreated group after five and seven days but not after two days of culture. Significantly reduced phosphorylated NFKB and A1AR protein levels were detected in dexamethasone treated compared to vehicle treated HTMCs after five days of culture.ConclusionsDexamethasone reduces MMP-2 and -9 secretion by HTMCs and this effect of dexamethasone is associated with reduced NFKB phosphorylation and A1AR expression.

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MiR-137 promotes cell growth and inhibits extracellular matrix protein expression in H2O2-induced human trabecular meshwork cells by targeting Src

Neuroscience Letters ◽

10.1016/j.neulet.2021.135902 ◽

2021 ◽

Vol 755 ◽

pp. 135902

Author(s):

Liang Wang ◽

Ying Tian ◽

Yan Cao ◽

Qiang Ma ◽

Shuai Zhao

Keyword(s):

Extracellular Matrix ◽

Cell Growth ◽

Protein Expression ◽

Trabecular Meshwork ◽

Matrix Protein ◽

Extracellular Matrix Protein ◽

Trabecular Meshwork Cells

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Gene and Protein Expression Changes in Human Trabecular Meshwork Cells Treated with Transforming Growth Factor-

Investigative Ophthalmology & Visual Science ◽

10.1167/iovs.04-0535 ◽

2004 ◽

Vol 45 (11) ◽

pp. 4023-4034 ◽

Cited By ~ 84

Author(s):

X. Zhao

Keyword(s):

Growth Factor ◽

Protein Expression ◽

Trabecular Meshwork ◽

Transforming Growth Factor ◽

Trabecular Meshwork Cells ◽

Gene And Protein Expression

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Cathepsin B Localizes in the Caveolae and Participates in the Proteolytic Cascade in Trabecular Meshwork Cells. Potential New Drug Target for the Treatment of Glaucoma

Journal of Clinical Medicine ◽

10.3390/jcm10010078 ◽

2020 ◽

Vol 10 (1) ◽

pp. 78

Author(s):

April Nettesheim ◽

Myoung Sup Shim ◽

Angela Dixon ◽

Urmimala Raychaudhuri ◽

Haiyan Gong ◽

...

Keyword(s):

Trabecular Meshwork ◽

Cathepsin B ◽

Molecular Mechanisms ◽

Culture Media ◽

Ecm Remodeling ◽

Trabecular Meshwork Cells ◽

Proteolytic Cascade

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. Previous work conducted in our laboratory identified the lysosomal enzyme cathepsin B (CTSB) to be expressed on the cellular surface and to be secreted into the culture media in trabecular meshwork (TM) cells. Here, we further investigated the role of CTSB on ECM remodeling and outflow physiology in vitro and in CSTBko mice. Our results indicate that CTSB localizes in the caveolae and participates in the pericellular degradation of ECM in TM cells. We also report here a novel role of CTSB in regulating the expression of PAI-1 and TGFβ/Smad signaling in TM cells vitro and in vivo in CTSBko mice. We propose enhancing CTSB activity as a novel therapeutic target to attenuate fibrosis and ECM deposition in the glaucomatous outflow pathway.

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