May 2005
Volume 46, Issue 13
ARVO Annual Meeting Abstract  |   May 2005
Actin Depolymerizing Agents Induce Activation of MMP–2 in Trabecular Meshwork Cells
Author Affiliations & Notes
  • R.K. Sanka
    Duke University School of Medicine, Durham, NC
  • D.L. Epstein
    Duke University School of Medicine, Durham, NC
  • P.V. Rao
    Ophthalmology, Pharmacology,
    Duke University School of Medicine, Durham, NC
  • Footnotes
    Commercial Relationships  R.K. Sanka, None; D.L. Epstein, Duke University F; P.V. Rao, None.
  • Footnotes
    Support  RO1 EY–12201, EY–13573 (PVR), RPB
Investigative Ophthalmology & Visual Science May 2005, Vol.46, 1352. doi:
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      R.K. Sanka, D.L. Epstein, P.V. Rao; Actin Depolymerizing Agents Induce Activation of MMP–2 in Trabecular Meshwork Cells . Invest. Ophthalmol. Vis. Sci. 2005;46(13):1352.

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      © ARVO (1962-2015); The Authors (2016-present)

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Abstract: : Purpose: We hypothesize that actin cytoskeletal reorganization and changes in cell morphology modulate the secretion and activation of matrix metalloproteinases (MMPs), which in turn, may influence aqueous humor outflow facility. The goal of this study was to examine the relationship between changes in the actin cytoskeletal organization and matrix metalloproteinase–2 (MMP–2) activity in trabecular meshwork (TM) cells. Methods: Activation of MMP–2 was evaluated by gelatin zymography and Western Blot analysis of serum–free culture medium conditioned by porcine TM cells treated with latrunculin A, cytochalasin D, ethacrynic acid or inhibitors of Rho kinase and protein kinase C. Changes in the protein levels of TIMP–2 and MT1–MMP were determined in porcine TM cell cultures by Western Blot analysis. The effects of actin depolymerizing agents on the expression of MT1–MMP was also determined in human TM cells by semiquantitative RT–PCR analysis. Changes in cell morphology and actin cytoskeletal organization were evaluated by staining with rhodamine–phalloidin and phase contrast microscopy, respectively. Results: Treatment of porcine TM cells with ethacrynic acid (100 µM), cytochalasin D (25 µM), and latrunculin A (0.25 µM) led to an activation of MMP–2 that appeared to correlate well with changes in cell morphology and actin cytoskeletal reorganization. Protein levels of TIMP–2 did not appear to be altered under these conditions. Treatment of human TM cells with latrunculin A (0.25 uM) led to an upregulation of MT1–MMP expression, while treatment with Y–27632 (25 uM) resulted in a downregulation of MT1–MMP expression in comparison to controls. Conclusions: These data demonstrate that actin depolymerizing agents such as latrunculin A, ethacrynic acid, and cytochalasin D increase activation of MMP–2 in TM cells implying the existence of a relationship between the integrity of actomyosin organization and ECM turnover in TM cells. Therefore, cytoskeletal–acting drugs may possibly influence aqueous humor outflow facility through multiple potential mechanisms.

Keywords: extracellular matrix • cytoskeleton • trabecular meshwork 

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