Mechanical stretch upregulates connexin43 in human trabecular meshwork cells

2019 ◽  
Author(s):  
Nikoleta Tellios ◽  
Mary Feng ◽  
Nancy Chen ◽  
Hong Liu ◽  
Vasiliki Tellios ◽  
...  
Keyword(s):  
Trabecular Meshwork ◽  
Mechanical Stretch ◽  
Trabecular Meshwork Cells

scholarly journals Expression of mRNAs, miRNAs, and lncRNAs in Human Trabecular Meshwork Cells Upon Mechanical Stretch

2020 ◽  
Vol 61 (5) ◽  
pp. 2
Author(s):  
Hannah Youngblood ◽  
Jingwen Cai ◽  
Michelle D. Drewry ◽  
Inas Helwa ◽  
Eric Hu ◽  
...  
Keyword(s):  
Trabecular Meshwork ◽  
Mechanical Stretch ◽  
Trabecular Meshwork Cells

scholarly journals Genome-wide Expression Profiling and Pathway Analysis in Cyclic Stretched Human Trabecular Meshwork Cells

2018 ◽  
Author(s):  
Michelle D. Drewry ◽  
Jingwen Cai ◽  
Inas Helwa ◽  
Eric Hu ◽  
Sabrina Liu ◽  
...  
Keyword(s):  
Mechanical Stress ◽  
Pathway Analysis ◽  
Trabecular Meshwork ◽  
Target Genes ◽  
Mechanical Stretch ◽  
Differentially Expressed ◽  
Receptor Protein ◽  
Trabecular Meshwork Cells ◽  
Differentially Expressed Mirnas ◽  
Significant Enrichment

AbstractPurposeRegulation of intraocular pressure is dependent upon homeostatic responses of trabecular meshwork (TM) cells to mechanical stretch. Despite the important roles of miRNAs in regulating TM function and aqueous outflow, it remains unclear how miRNA and their target genes interact in response to physiological cyclic mechanical stretch. We aimed to identify differentially expressed miRNAs and their potential targets in human TM cells in response to cyclic mechanical stress.MethodsMonolayers of TM cells from non-glaucomatous donors (n=3-6) were cultured in the presence or absence of 15% mechanical stretch, 1 cycle/s, for 6 or 24-hours using computer-controlled Flexcell Unit. We profiled the expression of 800 miRNAs using NanoString Human miRNA assays and identified differentially expressed miRNAs using the Bioconductor Limma package. We identified differentially expressed genes using Operon Human Oligo Arrays with GeneSpring software. Pathway analysis with WebGestalt identified stretch-related pathways. We used Integrative miRNA Target Finder from Ingenuity Pathway Analysis to identify potential miRNA-mRNA regulations.ResultsWe identified 540 unique genes and 74 miRNAs with differential expression in TM cells upon cyclic mechanical stretch. Pathway analysis indicated the significant enrichment of genes involved in Wnt-signaling, receptor protein serine/threonine kinase signaling, TGF-β pathway, and response to unfolded protein. We also identified several miRNA master regulators, including miR-19b-3p and miR-93-5p, which may act as switches to control several mechano-responsive genes.ConclusionsThis study suggests that cyclic mechanical stress of TM cells triggers alterations in the expression of both mRNAs and miRNAs implicated in glaucoma-associated pathways.

scholarly journals Primary cilia and the reciprocal activation of AKT and SMAD2/3 regulate stretch-induced autophagy in trabecular meshwork cells

2021 ◽  
Vol 118 (13) ◽  
pp. e2021942118
Author(s):  
Myoung Sup Shim ◽  
April Nettesheim ◽  
Angela Dixon ◽  
Paloma B. Liton
Keyword(s):  
Trabecular Meshwork ◽  
Primary Cilia ◽  
Molecular Mechanisms ◽  
Ex Vivo ◽  
Mechanical Stretch ◽  
Cell Types ◽  
Elevated Pressure ◽  
Compensatory Response ◽  
Protein Levels ◽  
Trabecular Meshwork Cells

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. We report that primary cilia act as a mechanosensor for CMS-induced autophagy and identified a cross-regulatory talk between AKT1 and noncanonical SMAD2/3 signaling as critical components of primary cilia-mediated activation of autophagy by mechanical stretch. Furthermore, we demonstrated the physiological significance of our findings in ex vivo perfused eyes. Removal of primary cilia disrupted the homeostatic IOP compensatory response and prevented the increase in LC3-II protein levels in response to elevated pressure challenge, strongly supporting a role of primary cilia-mediated autophagy in regulating IOP homeostasis.

scholarly journals Mechanical stretch induces Ca2+ influx and extracellular release of PGE2 through Piezo1 activation in trabecular meshwork cells

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Takatoshi Uchida ◽  
Shota Shimizu ◽  
Reiko Yamagishi ◽  
Suzumi M. Tokuoka ◽  
Yoshihiro Kita ◽  
...  
Keyword(s):  
Arachidonic Acid ◽  
Intraocular Pressure ◽  
Trabecular Meshwork ◽  
Pressure Fluctuations ◽  
Mechanical Stretch ◽  
Cell Contraction ◽  
Trabecular Meshwork Cells ◽  
Extracellular Release ◽  
Main Pathway ◽  
Outflow Pathway

AbstractThe trabecular meshwork (TM) constitutes the main pathway for aqueous humor drainage and is exposed to complex intraocular pressure fluctuations. The mechanism of homeostasis in which TM senses changes in intraocular pressure and leads to normal levels of outflow resistance is not yet well understood. Previous reports have shown that Piezo1, a mechanically-activated cation channel, is expressed in TM and isolated TM cells. Therefore, we tested hypothesis that Piezo1 may function in response to membrane tension and stretch in TM. In human trabecular meshwork (hTM) cells, PIEZO1 was showed to be abundantly expressed, and Piezo1 agonist Yoda1 and mechanical stretch caused a Piezo1-dependent Ca2+ influx and release of arachidonic acid and PGE2. Treatment with Yoda1 or PGE2 significantly inhibited hTM cell contraction. These results suggest that mechanical stretch stimuli in TM activates Piezo1 and subsequently regulates TM cell contraction by triggering Ca2+ influx and release of arachidonic acid and PGE2. Thus, Piezo1 could acts as a regulator of intraocular pressure (IOP) within the conventional outflow pathway and could be a novel therapeutic strategy to modulate IOP in glaucoma patients.

scholarly journals Functional Implications of Cross-Linked Actin Networks in Trabecular Meshwork Cells

2018 ◽  
Vol 45 (2) ◽  
pp. 783-794 ◽  
Author(s):  
Laura Duffy ◽  
Steven O’Reilly
Keyword(s):  
Trabecular Meshwork ◽  
Open Angle Glaucoma ◽  
Collagen Gel ◽  
Mechanical Stretch ◽  
Actin Networks ◽  
Trabecular Meshwork Cells ◽  
Microscopy Technique ◽  
Collagen Gel Contraction

Background/Aims: The Trabecular meshwork (TM) is the tissue responsible for outflow resistance and therefore intraocular pressure. TM cells contain a contractile apparatus that is composed of actin stress fibres which run parallel to the axis of the cell and are responsible for facilitating contraction. Cross-Linked Actin Networks (CLANs) are polygonal arrangements of actin that form a geodesic network found predominantly in TM cells both in situ and in vitro. The aim of this work is to determine the functional significance of CLANs in TM cells and to assess the effect of mechanical stretch stimulation on the induction (or not) of CLANs. Methods: We used collagen gel contraction models to demonstrate functional impairment of cells when induced to express CLANs in situ. Cyclic mechanical stretch was used to stimulate cells and measure CLANs Results: CLANs inhibited contraction and cyclic mechanical stretch induced CLANs. Furthermore, we also demonstrated that using shape alone we could predict the appearance of CLANs using a simple light microscopy technique. Conclusion: Taken together we have now shown, for the first time, a functional deficit In TM cells with CLANs Furthermore that shape alone can predict the appearance of CLAN containing cells. CLANs can now be linked to a functional effect and may underlie the appearance of CLANs with the pathology of primary open angle glaucoma (POAG).

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

2020 ◽  
Vol 0 (0) ◽  
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.

scholarly journals 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

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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