title: Hic-5 Regulates Actin Cytoskeletal Reorganization and Expression of Fibrogenic Markers and Myocilin in Trabecular Meshwork Cells.
abstract: OBJECTIVE
  To explore the role of inducible focal adhesion (FA) protein Hic-5 in actin cytoskeletal reorganization, FA formation, fibrogenic activity, and expression of myocilin in trabecular meshwork (TM) cells.
  
  
  METHODS
  Using primary cultures of human TM (HTM) cells, the effects of various external factors on Hic-5 protein levels, as well as the effects of recombinant Hic-5 and Hic-5 small interfering RNA (siRNA) on actin cytoskeleton, FAs, myocilin, α-smooth muscle actin (αSMA), and collagen-1 were determined by immunofluorescence and immunoblot analyses.
  
  
  RESULTS
  Hic-5 distributes discretely to the FAs in HTM cells and throughout the TM and Schlemm's canal of the human aqueous humor (AH) outflow pathway. Transforming growth factor-β2 (TGF-β2), endothelin-1, lysophosphatidic acid, hydrogen peroxide, and RhoA significantly increased Hic-5 protein levels in HTM cells in association with reorganization of actin cytoskeleton and FAs. While recombinant Hic-5 induced actin stress fibers, FAs, αv integrin redistribution to the FAs, increased levels of αSMA, collagen-1, and myocilin, Hic-5 siRNA suppressed most of these responses in HTM cells. Hic-5 siRNA also suppressed TGF-β2-induced fibrogenic activity and dexamethasone-induced myocilin expression in HTM cells.
  
  
  CONCLUSIONS
  Taken together, these results reveal that Hic-5, whose levels were increased by various external factors implicated in elevated intraocular pressure, induces actin cytoskeletal reorganization, FAs, expression of fibrogenic markers, and myocilin in HTM cells. These characteristics of Hic-5 in TM cells indicate its importance in regulation of AH outflow through the TM in both normal and glaucomatous eyes.
authors: Department of Ophthalmology, Duke University School of Medicine, Durham, North Carolina, United States.
authors: Padmanabhan Paranji
authors: PP
authors: Pattabiraman
authors: Department of Ophthalmology, Duke University School of Medicine, Durham, North Carolina, United States 2Department of Pharmacology and Cancer Biology, Duke University School of Medicine, Durham, North Carolina, United States.
authors: Ponugoti Vasantha
authors: PV
authors: Rao
mesh_terms: D000199:Actins / Q000378:metabolism*; D002478:Cells, Cultured; D003598:Cytoskeletal Proteins / Q000096:biosynthesis / Q000235:genetics*; D005136:Eye Proteins / Q000096:biosynthesis / Q000235:genetics*; D005786:Gene Expression Regulation; D005901:Glaucoma / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D006023:Glycoproteins / Q000096:biosynthesis / Q000235:genetics*; D006801:Humans; D015151:Immunoblotting; D007150:Immunohistochemistry; D047908:Intracellular Signaling Peptides and Proteins / Q000096:biosynthesis / Q000235:genetics*; D060588:LIM Domain Proteins / Q000096:biosynthesis / Q000235:genetics*; D012313:RNA / Q000235:genetics*; D015398:Signal Transduction; D014129:Trabecular Meshwork / Q000378:metabolism* / Q000473:pathology; D000099179:Myocilin
chemical_list: D000199:Actins; D003598:Cytoskeletal Proteins; D005136:Eye Proteins; D006023:Glycoproteins; D047908:Intracellular Signaling Peptides and Proteins; D060588:LIM Domain Proteins; D012313:RNA; D000099179:Myocilin; C490351:TGFB1I1 protein, human