Dataset Information

Biomechanical rigidity and quantitative proteomics analyses of segmental regions of the ocular trabecular meshwork at physiologic and elevated pressures

ABSTRACT: The extracellular matrix (ECM) of the ocular trabecular meshwork (TM) builds resistance to aqueous humor outflow, thereby regulating intraocular pressure (IOP). Glaucoma, a leading cause of blindness worldwide, is associated with changes in the ECM of the TM. The elastic modulus indicates glaucomatous TM is more rigid than age-matched normal TM; however, the biomechanical properties of segmental low (LF) and high flow (HF) TM regions in response to elevated pressure, are unknown. In this study, we measured the elastic modulus by atomic force microscopy (AFM) and measured protein expression differences in perfused human TM tissues by proteomics analyses. The elastic modulus of LF regions was 2.3-fold stiffer than HF regions at physiological (1x) pressure, and 7.4-fold or 3.5-fold stiffer than HF regions at elevated (2x) pressure after 24 or 72 hours, respectively. Quantitative proteomics using isobaric tandem mass tags (TMT), multi-notch isolation, high resolution, and extended multiplexing were used to compare protein expression levels between normal, LF, and HF regions at the two pressures. A total of 3730 proteins (2 peptides per protein) were identified from the ECM samples, and 2637 proteins were quantified. Statistically significant ECM proteins over expressed in LF compared with HF regions at 2x, and in HF regions at 1x compared with 2x pressure were determined. A sub-set of ECM proteins, including decorin, TGFβ-induced protein, keratocan, lumican, dermatopontin and thrombospondin 4, were common differential candidates in both comparisons. These data suggest a correlation between the biomechanical properties of TM regions and differential levels of specific ECM proteins in response to elevated pressure.

INSTRUMENT(S): Orbitrap Fusion ETD

ORGANISM(S): Homo Sapiens (human)

TISSUE(S): Eye

DISEASE(S): Glaucoma

SUBMITTER: Phillip Wilmarth

LAB HEAD: Janice Vranka

PROVIDER: PXD006424 | Pride | 2018-01-22

REPOSITORIES: Pride

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Dataset's files

Source:

			Action	DRS
	1xHF_1xLF_candidates.xls	Xls
	2xHF_1xHF_candidates.xls	Xls
	2xHF_2xHF_candidates.xls	Xls
	2xLF_1xLF_candidates.xls	Xls
	ACOT-153_94ReRun_HumanEyeTM_TMT_combined_trimmedNorm_annotated.xlsx	Xlsx

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Publications

Biomechanical Rigidity and Quantitative Proteomics Analysis of Segmental Regions of the Trabecular Meshwork at Physiologic and Elevated Pressures.

Vranka Janice A JA Staverosky Julia A JA Reddy Ashok P AP Wilmarth Phillip A PA David Larry L LL Acott Ted S TS Russell Paul P Raghunathan Vijay Krishna VK

Investigative ophthalmology & visual science 20180101 1

<h4>Purpose</h4>The extracellular matrix (ECM) of the trabecular meshwork (TM) modulates resistance to aqueous humor outflow, thereby regulating IOP. Glaucoma, a leading cause of irreversible blindness worldwide, is associated with changes in the ECM of the TM. The elastic modulus of glaucomatous TM is larger than age-matched normal TM; however, the biomechanical properties of segmental low (LF) and high flow (HF) TM regions and their response to elevated pressure, are unknown.<h4>Methods</h4>We ...[more]

PMID: 29340639

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Project description:Impaired drainage of aqueous humor through the trabecular meshwork (TM) culminating in increased intraocular pressure is a major risk factor for glaucoma, a leading cause of blindness worldwide. Regulation of aqueous humor drainage through the TM, however, is poorly understood. The role of RhoA GTPase-mediated contractile activity, cell adhesive interactions, and gene expression in regulation of aqueous humor outflow was investigated using adenoviral vector-driven expression of constitutively active RhoA (RhoAV14). Organ cultured anterior segments from porcine eyes expressing RhoAV14 exhibited significant reduction of aqueous humor outflow. Cultured TM cells expressing RhoAV14 revealed strong contractile cell morphology, increased actin stress fibers and focal adhesions, along with increased levels of phosphorylated myosin II, and collagen IV, fibronectin and laminin. cDNA microarray analysis of RNA extracted from RhoAV14 expressing human TM cells revealed a significant increase in the expression of genes encoding extracellular matrix (ECM) proteins, cytokines, integrins, cytoskeletal proteins and signaling proteins. Conversely, various ECM proteins stimulated robust increases in phosphorylation of myosin II, paxillin and focal adhesion kinase, and activated Rho GTPase and actin stress fiber formation in TM cells, indicating a potential regulatory feedback interaction between ECM-induced mechanical strain and Rho GTPase-induced isometric tension in TM cells. Collectively, these data demonstrate that sustained activation of Rho GTPase signaling in the aqueous humor outflow pathway increases resistance to aqueous humor outflow through the trabecular pathway by influencing the contractile force, cell adhesive interactions, and the expression of ECM proteins and cytokines in TM cells. Keywords: Gene Expression Two condition experiment: Human trabecular mesh work cells infected with Adenivirus expressing GFP Vs Adenovirus expressing GFP and constitutively active RhoAV14