title: Elevated hydrostatic pressure triggers mitochondrial fission and decreases cellular ATP in differentiated RGC-5 cells.
abstract: OBJECTIVE
  Mitochondrial fission is a cellular response to stress that has an important role in neuronal cell death in neurodegenerative diseases. The purpose of this study was to determine whether elevated hydrostatic pressure induces mitochondrial fission and dysfunction in cultured retinal ganglion cells.
  
  
  METHODS
  RGC-5 cells were differentiated with succinyl concanavalin A (50 microg/mL) and transferred to a pressurized incubator in which 30 mm Hg of pressure was applied for 1, 2, or 3 days. As a control, differentiated cells from an identical passage were incubated simultaneously in a conventional incubator at each of the time points. Live RGC-5 cells were then labeled with a red fluorescent mitochondrial dye and mitochondrial morphology was assessed by fluorescence microscopy and electron microscopy. After elevated hydrostatic pressure, the cellular adenosine triphosphate (ATP) levels were also measured by a luciferase-based assay.
  
  
  RESULTS
  Mitochondrial fission, characterized by the conversion of tubular fused mitochondria into isolated small organelles, was triggered in >74.3% +/- 1.9% of mitochondria at 3 days after elevated hydrostatic pressure. Only 4.7% +/- 1.4% of nonpressurized control cells displayed mitochondrial fission after 3 days. Electron microscopy showed that elevated hydrostatic pressure for 3 days induced abnormal cristae depletion and decreased the length of the mitochondria. On elevation of hydrostatic pressure, the fission-linked protein, Drp-1 was translocated from the cytosol to the mitochondria. Elevated hydrostatic pressure also resulted in a significant, time-dependent reduction of cellular ATP.
  
  
  CONCLUSIONS
  Elevated hydrostatic pressure triggered mitochondrial fission, abnormal cristae depletion, Drp-1 translocation, and cellular ATP reduction in differentiated RGC-5 cells. Increased understanding of the molecular mechanisms that regulate the cellular response to elevated pressure including mitochondrial fission may provide new therapeutic targets for protecting RGCs from elevated hydrostatic pressure.
authors: Hamilton Glaucoma Center and Department of Ophthalmology, University of California San Diego, La Jolla, California 92037, USA. danielju@glaucoma.ucsd.edu
authors: Won-Kyu
authors: WK
authors: Ju
authors: Quan
authors: Q
authors: Liu
authors: Keun-Young
authors: KY
authors: Kim
authors: Jonathan G
authors: JG
authors: Crowston
authors: James D
authors: JD
authors: Lindsey
authors: Neeraj
authors: N
authors: Agarwal
authors: Mark H
authors: MH
authors: Ellisman
authors: Guy A
authors: GA
authors: Perkins
authors: Robert N
authors: RN
authors: Weinreb
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism*; D000818:Animals; D017209:Apoptosis; D015153:Blotting, Western; D002454:Cell Differentiation; D002470:Cell Survival; D002478:Cells, Cultured; D003600:Cytosol / Q000378:metabolism; D034281:Dynamins / Q000378:metabolism; D006874:Hydrostatic Pressure; D008856:Microscopy, Fluorescence; D008928:Mitochondria / Q000378:metabolism / Q000473:pathology* / Q000648:ultrastructure; D051381:Rats; D012165:Retinal Ganglion Cells / Q000378:metabolism / Q000473:pathology*
chemical_list: D000255:Adenosine Triphosphate; C519851:Dnm1l protein, rat; D034281:Dynamins