title: Targeting the p53 pathway to protect the neonatal ischemic brain.
abstract: OBJECTIVE
  To investigate whether inhibition of mitochondrial p53 association using pifithrin-μ (PFT-μ) represents a potential novel neuroprotective strategy to combat perinatal hypoxic-ischemic (HI) brain damage.
  
  
  METHODS
  Seven-day-old rats were subjected to unilateral carotid artery occlusion and hypoxia followed by intraperitoneal treatment with PFT-μ, an inhibitor of p53 mitochondrial association or PFT-α an inhibitor of p53 transcriptional activity. Cerebral damage, sensorimotor and cognitive function, apoptotic pathways (cytosolic cytochrome c, Smac/DIABLO, active caspase 3), and oxidative stress (lipid peroxidation and PARP-1 cleavage) were investigated.
  
  
  RESULTS
  PFT-μ treatment completely prevented the HI-induced increase in mitochondrial p53 association at 3 hours and reduced neuronal damage at 48 hours post-HI. PFT-μ had long-term (6-10 weeks post-HI) beneficial effects as sensorimotor and cognitive outcome improved and infarct size was reduced by ~79%. Neuroprotection by PFT-μ treatment was associated with strong inhibition of apoptotic pathways and reduced oxidative stress. Unexpectedly, PFT-μ also inhibited HI-induced upregulation of p53 target genes. However, the neuroprotective effect of inhibiting only p53 transcriptional activity by PFT-α was significantly smaller and did not involve reduced oxidative stress.
  
  
  CONCLUSIONS
  We are the first to show that prevention of mitochondrial p53 association by PFT-μ strongly improves functional outcome and decreases lesion size after neonatal HI. PFT-μ not only inhibits mitochondrial release of cytochrome c, but also inhibits oxidative stress. We propose that as a consequence nuclear accumulation of p53 and transcription of proapoptotic target genes are prevented. In conclusion, targeting p53 mitochondrial association by PFT-μ may develop into a novel and powerful neuroprotective strategy.
authors.affiliation: Laboratory of Neuroimmunology and Developmental Origins of Disease, University Medical Center Utrecht, Utrecht, The Netherlands.
authors.forename: Cora H
authors.initials: CH
authors.lastname: Nijboer
authors.forename: Cobi J
authors.initials: CJ
authors.lastname: Heijnen
authors.forename: Michael A
authors.initials: MA
authors.lastname: van der Kooij
authors.forename: Jitske
authors.initials: J
authors.lastname: Zijlstra
authors.forename: Cindy T J
authors.initials: CT
authors.lastname: van Velthoven
authors.forename: Carsten
authors.initials: C
authors.lastname: Culmsee
authors.forename: Frank
authors.initials: F
authors.lastname: van Bel
authors.forename: Henrik
authors.initials: H
authors.lastname: Hagberg
authors.forename: Annemieke
authors.initials: A
authors.lastname: Kavelaars
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D017209:Apoptosis / Q000502:physiology; D052160:Benzothiazoles / Q000494:pharmacology* / Q000627:therapeutic use; D015415:Biomarkers / Q000378:metabolism; D001921:Brain / Q000187:drug effects* / Q000378:metabolism* / Q000473:pathology; D020925:Hypoxia-Ischemia, Brain / Q000473:pathology / Q000517:prevention & control*; D008928:Mitochondria / Q000187:drug effects; D018696:Neuroprotective Agents / Q000494:pharmacology* / Q000627:therapeutic use; D018384:Oxidative Stress; D051381:Rats; D017208:Rats, Wistar; D014050:Toluene / Q000031:analogs & derivatives* / Q000494:pharmacology / Q000627:therapeutic use; D016896:Treatment Outcome; D016159:Tumor Suppressor Protein p53 / Q000037:antagonists & inhibitors / Q000378:metabolism*
chemical_list: D052160:Benzothiazoles; D015415:Biomarkers; D018696:Neuroprotective Agents; D016159:Tumor Suppressor Protein p53; D014050:Toluene; C121565:pifithrin