2. Academic Validation
  3. Role of the Autotaxin-LPA Pathway in Dexamethasone-Induced Fibrotic Responses and Extracellular Matrix Production in Human Trabecular Meshwork Cells

Role of the Autotaxin-LPA Pathway in Dexamethasone-Induced Fibrotic Responses and Extracellular Matrix Production in Human Trabecular Meshwork Cells

  • Invest Ophthalmol Vis Sci. 2018 Jan 1;59(1):21-30. doi: 10.1167/iovs.17-22807.
Megumi Honjo 1,  Nozomi Igarashi 1,  Junko Nishida 1,  Makoto Kurano 2 3,  Yutaka Yatomi 2 3 4,  Koji Igarashi 5,  Kuniyuki Kano 3 6,  Junken Aoki 3 6,  Makoto Aihara 1
Affiliations

Affiliations

  • 1 Department of Ophthalmology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan.
  • 2 Department of Clinical Laboratory Medicine, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan.
  • 3 CREST, Japan Science and Technology Corporation (JST), Saitama, Japan.
  • 4 Department of Clinical Laboratory, The University of Tokyo Hospital, Tokyo, Japan.
  • 5 Bioscience Division, Reagent Development Department, AIA Research Group, TOSOH Corporation, Kanagawa, Japan.
  • 6 Laboratory of Molecular and Cellular Biochemistry, Graduate School of Pharmaceutical Sciences, Tohoku University, Miyagi, Japan.
PMID: 29305605 DOI: 10.1167/iovs.17-22807
Abstract

Purpose: Dexamethasone (Dex) regulates aqueous humor outflow by inducing reorganization of the Cytoskeleton and extracellular matrix (ECM) production. Rho kinase (ROCK) has an important role in this process, but the upstream pathway leading to its activation remains elusive. The purpose of the study was to determine the role of Autotaxin (ATX), an Enzyme involved in the generation of lysophosphatidic acid (LPA), in the Dex-induced fibrotic response and ECM production in human trabecular meshwork (HTM) cells.

Methods: The expression of ATX in specimens from glaucoma patients was investigated by immunohistochemistry. Regulation of ATX expression and the changes in actin Cytoskeleton, ECM production, Myosin light chain (MLC) and cofilin phosphorylation, ATX secretion, and lysophospholipase D (lysoPLD) activity induced by Dex treatment in HTM cells were determined by immunofluorescence, real-time quantitative PCR, immunoblot, and the two-site immunoenzymetric and lysoPLD assays.

Results: Significant ATX expression was found in conventional outflow pathway specimens from glaucoma patients. Dex treatment induced increases in ATX mRNA levels, protein expression, and secretion in HTM cells in association with reorganization of Cytoskeleton and ECM accumulation. Significant suppression of these aforementioned changes was observed after ATX/LPA-receptor/ROCK inhibition as well as suppression of fibrotic changes and MLC and cofilin phosphorylation in HTM cells.

Conclusions: The results of this study, including the robust induction of ATX by Dex treatment, in association with fibrotic changes and ECM production in HTM cells, collectively suggest a potential role for ATX-LPA pathway in the regulation of aqueous humor outflow and IOP in glaucomatous eyes.

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