Role of HSP70 in motoneuron survival after excitotoxic stress in a rat spinal cord injury model in vitro.
The outcome for gait recovery from paralysis due to spinal lesion remains uncertain even when damage is limited. One critical factor is the survival of motoneurons, which are very vulnerable cells. To clarify the early pathophysiological mechanisms of spinal damage, an in vitro injury model of the rat spinal cord caused by moderate excitotoxicity was used. With this preparation we investigated whether motoneuron survival was dependent on the expression of the neuroprotective protein HSP70. In the present study excitotoxicity evoked by kainate induced delayed (24 h) loss (35%) of motoneurons, which became pyknotic with translocation of the cell death biomarker apoptosis-inducing factor (AIF) to the nucleus. This process was concomitant with suppression of locomotor network electrical activity. Surviving cells showed strong expression of HSP70 without nuclear AIF. The HSP70 inhibitor VER155008 per se induced neurotoxicity similar to that of kainate, while the HSP90 inhibitor geldanamycin did not damage spinal tissue. Electrophysiological recording following kainate or VER155008 indicated depression of motoneuron field potentials, with decreased excitability and impaired synaptic transmission. When these two drugs were applied together, more intense neurotoxicity emerged. Our data indicate that HSP70 was one important contributor to motoneuron survival and suggest that enhancing HSP70 activity is a potential future strategy for neuroprotecting these cells.
Neuroscience Department, Scuola Internazionale Superiore di Studi Avanzati (SISSA), Via Bonomea 265, 34136 Trieste, Italy.
Ayisha
A
Shabbir
Neuroscience Department, Scuola Internazionale Superiore di Studi Avanzati (SISSA), Via Bonomea 265, 34136 Trieste, Italy.
Elena
E
Bianchetti
Neuroscience Department, Scuola Internazionale Superiore di Studi Avanzati (SISSA), Via Bonomea 265, 34136 Trieste, Italy.|Department of Biotechnology, University of Rijeka, Rijeka, Croatia.
Renato
R
Cargonja
Neuroscience Department, Scuola Internazionale Superiore di Studi Avanzati (SISSA), Via Bonomea 265, 34136 Trieste, Italy.|Department of Biotechnology, University of Rijeka, Rijeka, Croatia.
Antonela
A
Petrovic
Neuroscience Department, Scuola Internazionale Superiore di Studi Avanzati (SISSA), Via Bonomea 265, 34136 Trieste, Italy.|Department of Biotechnology, University of Rijeka, Rijeka, Croatia.
Miranda
M
Mladinic
Neuroscience Department, Scuola Internazionale Superiore di Studi Avanzati (SISSA), Via Bonomea 265, 34136 Trieste, Italy.
Kristina
K
Pilipović
Neuroscience Department, Scuola Internazionale Superiore di Studi Avanzati (SISSA), Via Bonomea 265, 34136 Trieste, Italy.
Andrea
A
Nistri
D000818:Animals; D000831:Animals, Newborn; D051033:Apoptosis Inducing Factor / Q000378:metabolism; D016227:Benzoquinones / Q000494:pharmacology; D016923:Cell Death / Q000187:drug effects / Q000502:physiology; D002470:Cell Survival / Q000187:drug effects / Q000502:physiology; D002491:Central Nervous System Agents / Q000494:pharmacology; D004195:Disease Models, Animal; D005260:Female; D018840:HSP70 Heat-Shock Proteins / Q000037:antagonists & inhibitors / Q000378:metabolism*; D007608:Kainic Acid; D047029:Lactams, Macrocyclic / Q000494:pharmacology; D008124:Locomotion / Q000187:drug effects / Q000502:physiology; D008159:Lumbar Vertebrae; D008297:Male; D008839:Microelectrodes; D009046:Motor Neurons / Q000187:drug effects / Q000473:pathology / Q000502:physiology*; D011684:Purine Nucleosides / Q000494:pharmacology; D017208:Rats, Wistar; D013116:Spinal Cord / Q000187:drug effects / Q000473:pathology / Q000503:physiopathology*; D013119:Spinal Cord Injuries / Q000473:pathology / Q000503:physiopathology*; D013904:Thoracic Vertebrae
C494831:Aifm1 protein, rat; D051033:Apoptosis Inducing Factor; D016227:Benzoquinones; D002491:Central Nervous System Agents; D018840:HSP70 Heat-Shock Proteins; D047029:Lactams, Macrocyclic; D011684:Purine Nucleosides; C550733:VER 155008; D007608:Kainic Acid; C001277:geldanamycin
apoptosis-inducing factor; caspase-independent cell death; excitotoxicity; heat shock proteins; spinal networks