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The Dose Dependent Response of Dexamethasone on the Genotype and Phenotype of Trabecular Meshwork Cells

Mount, Zachary
http://orcid.org/0000-0003-2761-9359
http://rave.ohiolink.edu/etdc/view?acc_num=ucin1660819433928003

Abstract Details

2022, MS, University of Cincinnati, Engineering and Applied Science: Chemical Engineering.
Dexamethasone (DEX) is used to treat the aggressive inflammation that is associated with diseases like diabetic macular edema, diabetic retinopathy, uveitis, and age-related macular degeneration (AMD). Prolonged use of DEX can lead to side effects like cataracts and elevated intraocular pressure (IOP). Chronically elevated IOP can lead to the development of glaucoma, a disease characterized by damage to the optic nerve. This glucocorticoid-induced ocular hypertension (GC-OHT) occurs in ~40% of patients without glaucoma and ~90% of patients with primary open angle glaucoma (POAG). GC-OHT is thought to be caused by the ability of DEX to remodel the extracellular matrix (ECM) and actin cytoskeleton on trabecular meshwork cells, which drain the aqueous humor (AH). IOP is controlled through the production and drainage of AH. To reduce the GC-OHT caused by DEX while still allowing for an efficacious treatment, this study tests the effect of dose of DEX, and a combination therapy of DEX and Ripasudil (RIP), on the phenotype and genotype of TM cells. RIP is a Rho kinase inhibitor that can reduce IOP, by affecting the actin cytoskeleton of TM cells. TM cells were treated with various doses of DEX and combination of DEX and RIP for 6 days. The phenotype was tested using FITC-dextran permeability, collagen contractility and actin staining. Each of these assays showed a dose-dependent effect of DEX on the TM cell phenotype. Permeability decreases, contractility increases, and the average amount of actin per cell increases in response to an increasing dose of DEX. RIP was able to reverse these effects in contractility and actin levels but not permeability. TM cells dosed with low (10 nM) and high (10 µM) DEX were subject to RNA sequencing. Differential gene expression analysis was done between control and 10 nM DEX (Group A), control and 10 µM DEX (Group B), and 10 nM and 10 µM DEX treatments (Group G). Pathway enrichment analysis was done on the differentially expressed genes (DEGs) of these groupings. Pathway enrichment analysis found genes from Group A to be significantly grouped in the regulation of the actin cytoskeleton, ECM-receptor interactions, focal adhesion, cell adhesion molecules, WNT signaling, and PI3K-AKT signaling pathways. Genes from Group B were significantly grouped in the focal adhesion and regulation of actin cytoskeleton pathways, and genes from group G were significantly grouped in the cell cycle and cellular senescence pathways. Genes associated with the regulation of actin cytoskeleton might affect the cellular contractility, including the activation of RhoA through VAV3, elevated cross actin linking through IQGAP2, and less actin depolymerization through LIMK2. The upregulation of cell adhesion molecules, such as the CLDN family of genes, may explain the reduced permeability affected by DEX. ECM-receptor interactions may affect WNT signaling through the ability of TNC to suppress DKK1 at the transcriptional level. WNT signaling may participate in the effect of DEX on the actin cytoskeleton through downregulation of the canonical pathway and the activation of the ROR2/RhoA/ROCK axis, as well as increasing GC receptor signaling.
Yoonjee Park, Ph.D. (Committee Member)
Winston Kao, Ph.D. (Committee Member)
Greg Harris, Ph.D. (Committee Member)
44 p.
Chemical Engineering
Glaucoma; Glucocorticoid; Trabecular Meshwork; RNA Sequencing; Permeability; Contractility

Recommended Citations

Citations

  • Mount, Z. (2022). The Dose Dependent Response of Dexamethasone on the Genotype and Phenotype of Trabecular Meshwork Cells [Master's thesis, University of Cincinnati]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1660819433928003

    APA Style (7th edition)

  • Mount, Zachary. The Dose Dependent Response of Dexamethasone on the Genotype and Phenotype of Trabecular Meshwork Cells. 2022. University of Cincinnati, Master's thesis. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=ucin1660819433928003.

    MLA Style (8th edition)

  • Mount, Zachary. "The Dose Dependent Response of Dexamethasone on the Genotype and Phenotype of Trabecular Meshwork Cells." Master's thesis, University of Cincinnati, 2022. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1660819433928003

    Chicago Manual of Style (17th edition)

ucin1660819433928003
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This open access ETD is published by University of Cincinnati and OhioLINK.