title: Caspase-mediated cleavage of actin and tubulin is a common feature and sensitive marker of axonal degeneration in neural development and injury.
abstract: BACKGROUND
  Axon degeneration is a characteristic feature of multiple neuropathologic states and is also a mechanism of physiological neurodevelopmental pruning. The vast majority of in vivo studies looking at axon degeneration have relied on the use of classical silver degeneration stains, which have many limitations including lack of molecular specificity and incompatibility with immunolabeling methods. Because Wallerian degeneration is well known to involve cytoskeletal disassembly and because caspases are recently implicated in aspects of this process, we asked whether antibodies directed at caspase-generated neoepitopes of beta-actin and alpha-tubulin would be useful immunohistochemical markers of pathological and developmental axon degeneration.
  
  
  RESULTS
  Here we demonstrate that several forms of axon degeneration involve caspase-mediated cleavage of these cytoskeletal elements and are well-visualized using this approach. We demonstrate the generation of caspase-induced neoepitopes in a) an in vitro neuronal culture model using nerve growth factor-deprivation-induced degeneration and b) an in vivo model using ethanol-induced neuronal apoptosis, and c) during normal developmental pruning and physiological turnover of neurons.
  
  
  CONCLUSIONS
  Our findings support recent experimental data that suggests caspase-3 and caspase-6 have specific non-redundant roles in developmental pruning. Finally, these findings may have clinical utility, as these markers highlight degenerating neurites in human hypoxic-ischemic injury. Our work not only confirms a common downstream mechanism involved in axon degeneration, but also illuminates the potential utility of caspase-cleavage-neoepitope antibodies as markers of neurodegeneration.
authors: Jennifer D
authors: JD
authors: Sokolowski
authors: Kanchana K
authors: KK
authors: Gamage
authors: Daniel S
authors: DS
authors: Heffron
authors: Andrea C
authors: AC
authors: Leblanc
authors: Christopher D
authors: CD
authors: Deppmann
authors: Department of Pathology, University of Virginia School of Medicine, Charlottesville, VA 22908, USA. jwm2m@virginia.edu.
authors: James W
authors: JW
authors: Mandell
mesh_terms: D000199:Actins / Q000378:metabolism*; D000328:Adult; D020269:Alcoholic Neuropathy / Q000139:chemically induced / Q000150:complications*; D000818:Animals; D000831:Animals, Newborn; D017209:Apoptosis / Q000187:drug effects; D020169:Caspases / Q000378:metabolism*; D002478:Cells, Cultured; D002492:Central Nervous System Depressants / Q000633:toxicity; D004195:Disease Models, Animal; D000431:Ethanol / Q000633:toxicity; D005260:Female; D005786:Gene Expression Regulation / Q000187:drug effects / Q000235:genetics; D006801:Humans; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D009419:Nerve Tissue Proteins / Q000378:metabolism; D009474:Neurons / Q000187:drug effects / Q000378:metabolism; D017207:Rats, Sprague-Dawley; D017783:Superior Cervical Ganglion / Q000166:cytology; D014404:Tubulin / Q000378:metabolism*; D014855:Wallerian Degeneration / Q000209:etiology* / Q000473:pathology*; D051028:bcl-2-Associated X Protein / Q000172:deficiency
chemical_list: D000199:Actins; D002492:Central Nervous System Depressants; D009419:Nerve Tissue Proteins; D014404:Tubulin; D051028:bcl-2-Associated X Protein; D000431:Ethanol; D020169:Caspases