title: RhoA Signaling and Synaptic Damage Occur Within Hours in a Live Pig Model of CNS Injury, Retinal Detachment.
abstract: OBJECTIVE
  The RhoA pathway is activated after retinal injury. However, the time of onset and consequences of activation are unknown in vivo. Based on in vitro studies we focused on a period 2 hours after retinal detachment, in pig, an animal whose retina is holangiotic and contains cones.
  
  
  METHODS
  Under anesthesia, retinal detachments were created by subretinal injection of a balanced salt solution. Two hours later, animals were sacrificed and enucleated for GTPase activity assays and quantitative Western blot and confocal microscopy analyses.
  
  
  RESULTS
  RhoA activity with detachment was increased 1.5-fold compared to that in normal eyes or in eyes that had undergone vitrectomy only. Increased phosphorylation of myosin light chain, a RhoA effector, also occurred. By 2 hours, rod cells had retracted their terminals toward their cell bodies, disrupting the photoreceptor-to-bipolar synapse and producing significant numbers of spherules with SV2 immunolabel in the outer nuclear layer of the retina. In eyes with detachment, distant retina that remained attached also showed significant increases in RhoA activity and synaptic disjunction. Increases in RAC1 activity and glial fibrillary acidic protein (GFAP) were not specific for detachment, and sprouting of bipolar dendrites, reported for longer detachments, was not seen. The RhoA kinase inhibitor Y27632 significantly reduced axonal retraction by rod cells.
  
  
  CONCLUSIONS
  Activation of the RhoA pathway occurs quickly after injury and promotes synaptic damage that can be controlled by RhoA kinase inhibition. We suggest that retinal detachment joins the list of central nervous system injuries, such as stroke and spinal cord injury, that should be considered for rapid therapeutic intervention.
authors.affiliation: Department of Pharmacology Physiology, and Neuroscience, New Jersey Medical School-Rutgers Biomedical Health Sciences, Rutgers University, Newark, New Jersey, United States.
authors.forename: Jianfeng
authors.initials: J
authors.lastname: Wang
authors.affiliation: Institute of Ophthalmology and Visual Science, New Jersey Medical School-Rutgers Biomedical Health Sciences, Rutgers University, Newark, New Jersey, United States.
authors.forename: Marco
authors.initials: M
authors.lastname: Zarbin
authors.affiliation: Institute of Ophthalmology and Visual Science, New Jersey Medical School-Rutgers Biomedical Health Sciences, Rutgers University, Newark, New Jersey, United States.
authors.forename: Ilene
authors.initials: I
authors.lastname: Sugino
authors.affiliation: Department of Microbiology, Biochemistry, and Medical Genetics, New Jersey Medical School-Rutgers Biomedical Health Sciences, Rutgers University, Newark, New Jersey, United States.
authors.forename: Ian
authors.initials: I
authors.lastname: Whitehead
authors.affiliation: Department of Pharmacology Physiology, and Neuroscience, New Jersey Medical School-Rutgers Biomedical Health Sciences, Rutgers University, Newark, New Jersey, United States.
authors.forename: Ellen
authors.initials: E
authors.lastname: Townes-Anderson
mesh_terms: D000577:Amides / Q000494:pharmacology; D000818:Animals; D024722:Cardiac Myosins / Q000378:metabolism; D004195:Disease Models, Animal; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D005260:Female; D066298:In Vitro Techniques; D008297:Male; D018994:Myosin Light Chains / Q000378:metabolism; D010766:Phosphorylation / Q000502:physiology; D051571:Protein Kinase C-alpha; D011725:Pyridines / Q000494:pharmacology; D012163:Retinal Detachment / Q000503:physiopathology*; D017948:Retinal Rod Photoreceptor Cells / Q000187:drug effects; D015398:Signal Transduction / Q000502:physiology; D034421:Sus scrofa; D013552:Swine; D013569:Synapses / Q000201:enzymology*; D020830:rac1 GTP-Binding Protein / Q000378:metabolism; D020742:rhoA GTP-Binding Protein / Q000378:metabolism / Q000502:physiology*
chemical_list: D000577:Amides; D004791:Enzyme Inhibitors; D018994:Myosin Light Chains; D011725:Pyridines; C107184:myosin light chain 2; C108830:Y 27632; D051571:Protein Kinase C-alpha; D024722:Cardiac Myosins; D020830:rac1 GTP-Binding Protein; D020742:rhoA GTP-Binding Protein