BIOLOGY OF TRABECULAR MESHWORK IN HEALTH AND DISEASE

Summary

Principal Investigator: BEATRICE YUE
Abstract: DESCRIPTION: The trabecular meshwork (TM) is a major site for regulation of the aqueous humor outflow. Cells in the TM are essential for maintenance of the normal aqueous outflow. Aberrations of cell integrity may be a key step toward obstruction of the outflow, intraocular pressure elevation, and glaucomatous conditions. We have instituted a program in our laboratory to define the TM biology and have accumulated a significant body of information regarding the basic characteristics of TM cells and the dynamics of TM cell-matrix interactions. During the past grant period, we have concentrated on studies of myocilin, a gene linked directly to open angle glaucomas. We have shown that myocilin is localized at both intra- and extra-cellular sites. When overexpressed in TM cells, or when present extracellularly in the matrix, myocilin causes a loss of actin stress fibers and focal adhesions, and elicits a de-adhesion activity. The alteration of the actin organization has led us to hypothesize that the myocilin effects may be mediated via signaling of the small GTPase Rho family. Members of the Rho family, Rho, Rac, and Cdc42, are well documented to be critical regulators of actin dynamics. In this renewal application, we propose to examine the Rho hypothesis in specific aim 1. The Rho GTPase activities in control and myocilin-transfected human TM cells will be compared. The activator and inhibitor of Rho, and constitutively active or dominant negative Rho, Rac, and Cdc42 expression vectors, will be used to determine whether Rho modulation reverts or modifies the myocilin-triggered phenotype. The involvement of Rho GTPases in mediating the effects of extracellular myocilin will be deciphered by comparing the phenotype displayed by Rho, Rac, and Cdc42 transfected and nontransfected TM cells on recombinant eukaryotic myocilin- or fibronectin/ myocilin-coated plates. The events associated with truncated and mutated myocilin will be explored. Studies will also be extended to perfusion organ cultures. In specific aim 2, we will pursue a theory that myocilin mutants may be misprocessed and/or misfolded to provoke unfolded protein response (UPR). This theory has been formulated based on findings that certain mutated forms of myocilin are not secreted and are retained inside the cells. We will study the intracellular trafficking, degradation and oligomerization of endogenous and overexpressed wild type and mutated myocilins in TM cells. The ubiquitination of myocilins will be examined and the chaperones associated with myocilin proteins will be identified. Results from cells transfected to overexpress wild type, truncated or mutated myocilin will be compared to assess whether the mutant processing is defective and UPR is induced by the mutants. The central hypothesis is that overexpressed and/or mutated myocilin may be deleterious to TM cells via different signaling pathways or mechanisms. The overall goal of our proposal is to illustrate the mechanisms to provide a deeper understanding regarding the pathogenesis of glaucomas.
Funding Period: 1984-12-01 - 2010-04-30
more information: NIH RePORT

Top Publications

  1. pmc Cellular processing of myocilin
    Ye Qiu
    Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago College of Medicine, Chicago, Illinois, United States of America
    PLoS ONE 9:e92845. 2014
  2. pmc Downregulation of LIM kinase 1 suppresses ocular inflammation and fibrosis
    Matvey Gorovoy
    Department of Pharmacology, College of Medicine, University of Illinois at Chicago, Chicago, IL 60612, USA
    Mol Vis 14:1951-9. 2008
  3. pmc Wnt activation by wild type and mutant myocilin in cultured human trabecular meshwork cells
    Xiang Shen
    Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago College of Medicine, Chicago, Illinois, United States of America
    PLoS ONE 7:e44902. 2012
  4. pmc Establishment of inducible wild type and mutant myocilin-GFP-expressing RGC5 cell lines
    Hongyu Ying
    Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago, College of Medicine, Chicago, Illinois, USA
    PLoS ONE 7:e47307. 2012
  5. pmc Optimized bacterial expression of myocilin proteins and functional comparison of bacterial and eukaryotic myocilins
    Bum Chan Park
    Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago College of Medicine, Chicago, IL 60612, USA
    Mol Vis 12:832-40. 2006
  6. pmc Differential expression of genes in cells cultured from juxtacanalicular trabecular meshwork and Schlemm's canal
    E Timothy O'Brien
    1 Department of Physics and Astronomy, University of North Carolina, Chapel Hill, North Carolina
    J Ocul Pharmacol Ther 30:291-9. 2014
  7. pmc Processing of optineurin in neuronal cells
    Xiang Shen
    Department of Ophthalmology and Visual Sciences, College of Medicine, University of Illinois, Chicago, Illinois 60612, USA
    J Biol Chem 286:3618-29. 2011
  8. pmc Suppression of transforming growth factor-β effects in rabbit subconjunctival fibroblasts by activin receptor-like kinase 5 inhibitor
    Jennifer Sapitro
    Department of Ophthalmology, Summa Health System, Akron, OH, USA
    Mol Vis 16:1880-92. 2010
  9. pmc Impairment of protein trafficking upon overexpression and mutation of optineurin
    BumChan Park
    Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago College of Medicine, Chicago, Illinois, United States of America
    PLoS ONE 5:e11547. 2010
  10. pmc Posttranslational modifications, localization, and protein interactions of optineurin, the product of a glaucoma gene
    Hongyu Ying
    Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago College of Medicine, Chicago, Illinois, United States of America
    PLoS ONE 5:e9168. 2010

Scientific Experts

  • BEATRICE YUE
  • A R Djalilian
  • Xiang Shen
  • Hongyu Ying
  • Ye Qiu
  • Rajalekshmy Shyam
  • Bum Chan Park
  • Takahisa Koga
  • Jeong Seok Park
  • BumChan Park
  • E Timothy O'Brien
  • Jennifer Sapitro
  • Matvey Gorovoy
  • Martin Tibudan
  • Tomoyo Koga
  • H Nakamura
  • Yanhong Wang
  • Zai Long Chi
  • Takeshi Iwata
  • Vijay Sutariya
  • KELLY K WENTZ-HUNTER
  • Hiroshi Nakamura
  • Michael Hewit
  • Sarah E Scott
  • Werner J Geldenhuys
  • Jeffrey J Dunmire
  • Joel Sugar
  • Tatyana Voyno-Yasenetskaya
  • Nirmala SundarRaj
  • Zhengping Jia
  • Mishan Samaraweera
  • Michael P Fautsch
  • Jun ichiro Tsutsui
  • Hidenobu Tanihara
  • Douglas H Johnson
  • Maiko Awai
  • W Rademaker
  • D P Edward
  • F Riley
  • H Sakai

Detail Information

Publications19

  1. pmc Cellular processing of myocilin
    Ye Qiu
    Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago College of Medicine, Chicago, Illinois, United States of America
    PLoS ONE 9:e92845. 2014
    ..In the present study, we investigated the processing of myocilin in human trabecular meshwork (TM) cells as well as in inducible, stable RGC5 cell lines...
  2. pmc Downregulation of LIM kinase 1 suppresses ocular inflammation and fibrosis
    Matvey Gorovoy
    Department of Pharmacology, College of Medicine, University of Illinois at Chicago, Chicago, IL 60612, USA
    Mol Vis 14:1951-9. 2008
    ..The purpose of this study was to determine if downregulation of LIM kinase 1 (LIMK1) by genetic deletion or direct application of LIMK1-targeted siRNA could suppress TGF-beta mediated ocular inflammation and fibrosis...
  3. pmc Wnt activation by wild type and mutant myocilin in cultured human trabecular meshwork cells
    Xiang Shen
    Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago College of Medicine, Chicago, Illinois, United States of America
    PLoS ONE 7:e44902. 2012
    ..We examined herein whether Wnt signaling pathway is involved in the myocilin phenotypes and whether P370L and Q368X mutants also display biological effects similar to those of the wild type myocilin...
  4. pmc Establishment of inducible wild type and mutant myocilin-GFP-expressing RGC5 cell lines
    Hongyu Ying
    Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago, College of Medicine, Chicago, Illinois, USA
    PLoS ONE 7:e47307. 2012
    ....
  5. pmc Optimized bacterial expression of myocilin proteins and functional comparison of bacterial and eukaryotic myocilins
    Bum Chan Park
    Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago College of Medicine, Chicago, IL 60612, USA
    Mol Vis 12:832-40. 2006
    ..coli) and to examine the biological effects of bacterially expressed myocilin as compared to eukaryotic myocilin on cultured human trabecular meshwork (TM) cells...
  6. pmc Differential expression of genes in cells cultured from juxtacanalicular trabecular meshwork and Schlemm's canal
    E Timothy O'Brien
    1 Department of Physics and Astronomy, University of North Carolina, Chapel Hill, North Carolina
    J Ocul Pharmacol Ther 30:291-9. 2014
    ....
  7. pmc Processing of optineurin in neuronal cells
    Xiang Shen
    Department of Ophthalmology and Visual Sciences, College of Medicine, University of Illinois, Chicago, Illinois 60612, USA
    J Biol Chem 286:3618-29. 2011
    ..A decreased PSMB5 level and an induced autophagy were also demonstrated in vivo in retinal ganglion cells of E50K transgenic mice, validating and making relevant the in vitro findings...
  8. pmc Suppression of transforming growth factor-β effects in rabbit subconjunctival fibroblasts by activin receptor-like kinase 5 inhibitor
    Jennifer Sapitro
    Department of Ophthalmology, Summa Health System, Akron, OH, USA
    Mol Vis 16:1880-92. 2010
    ....
  9. pmc Impairment of protein trafficking upon overexpression and mutation of optineurin
    BumChan Park
    Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago College of Medicine, Chicago, Illinois, United States of America
    PLoS ONE 5:e11547. 2010
    ..Here we determined whether, and how optineurin overexpression and E50K mutation affect the internalization of transferrin (Tf), widely used as a marker for receptor-mediated endocytosis...
  10. pmc Posttranslational modifications, localization, and protein interactions of optineurin, the product of a glaucoma gene
    Hongyu Ying
    Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago College of Medicine, Chicago, Illinois, United States of America
    PLoS ONE 5:e9168. 2010
    ..One of the candidate genes, optineurin, is linked principally to normal tension glaucoma, a subtype of POAG. The present study was undertaken to illustrate the basic characteristics of optineurin...
  11. pmc Wnt gene expression in human trabecular meshwork cells
    Rajalekshmy Shyam
    Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago College of Medicine, Chicago, IL, USA
    Mol Vis 16:122-9. 2010
    ..In addition, the effect of oxidative stress on Wnt signaling was evaluated...
  12. pmc Differential effects of myocilin and optineurin, two glaucoma genes, on neurite outgrowth
    Takahisa Koga
    Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago, College of Medicine, Chicago, IL 60612, USA
    Am J Pathol 176:343-52. 2010
    ..These results demonstrated that the two glaucoma genes, myocilin and optineurin, exhibited differential effects on neurite outgrowth. They may contribute to the development of neurodegenerative glaucoma via distinct mechanisms...
  13. pmc Effects of Sp1 overexpression on cultured human corneal stromal cells
    Xiang Shen
    Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago College of Medicine, Chicago, IL, USA
    Genes Cells 14:1133-9. 2009
    ..Furthermore, the apoptotic activity was unaffected in Sp1 transfectants but the proliferation was inhibited, consistent with the idea that Sp1 may play a role in differentiation of corneal cells...
  14. pmc Down-regulation of Notch signaling during corneal epithelial proliferation
    A R Djalilian
    Department of Ophthalmology, University of Illinois at Chicago, Chicago, IL 60612, USA
    Mol Vis 14:1041-9. 2008
    ..We evaluated the expression and activation of Notch pathway genes in the adult human and murine corneal epithelium during proliferation...
  15. pmc Rho GTPase and cAMP/protein kinase A signaling mediates myocilin-induced alterations in cultured human trabecular meshwork cells
    Xiang Shen
    Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago College of Medicine, 1855 W Taylor Street, Chicago, IL 60612, USA
    J Biol Chem 283:603-12. 2008
    ..cAMP/PKA activation and the downstream Rho inhibition are possible mechanisms by which myocilin in overabundance may lead to TM cell or tissue damage...
  16. ncbi Interaction between two glaucoma genes, optineurin and myocilin
    Bum Chan Park
    Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago College of Medicine, Chicago, IL, USA
    Genes Cells 12:969-79. 2007
    ..These results indicate that interaction exists between OPTN and MYOC genes. Regulation of MYOC expression by OPTN is achieved primarily through control of the mRNA stability...
  17. ncbi Rho-associated protein kinase inhibitor, Y-27632, induces alterations in adhesion, contraction and motility in cultured human trabecular meshwork cells
    Tomoyo Koga
    Department of Ophthalmology and Visual Science, Kumamoto University Graduate School of Medical Sciences, Honjo 1 1 1, Kumamoto 860 8556, Japan
    Exp Eye Res 82:362-70. 2006
    ..In conclusion, Y-27632 elicits profound effects on TM cell activities including adhesion, gel contraction, and cell motility. These Y-27632-induced changes of TM cells may be relevance to the physiology of the aqueous outflow system...
  18. pmc Histopathological and immunohistochemical studies of lenticules after epikeratoplasty for keratoconus
    H Nakamura
    Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago College of Medicine, 1855 W Taylor Street, Chicago, IL 60612, USA
    Br J Ophthalmol 89:841-6. 2005
    ..To examine histopathological and immunohistochemical changes in lenticules and host of corneal buttons from patients who previously underwent epikeratoplasty for keratoconus...