title: Activated Src kinases interact with the N-methyl-D-aspartate receptor after neonatal brain ischemia.
abstract: OBJECTIVE
  Neonatal stroke is associated with the N-methyl-D-aspartate receptor (NMDAR)-mediated excitotoxic brain injury. Src family kinases (SFKs) are considered to be the molecular hub for NMDAR regulation. We determined the relationship between SFKs activation and NMDAR tyrosine phosphorylation after neonatal hypoxia-ischemia (HI) and investigated the neuroprotective potential of a selective SFKs inhibitor, PP2 (4-amino-5-(4-chlorophenyl)-7-(t-butyl) pyrazolo [3, 4-d] pyramidine), against neonatal brain ischemic injury.
  
  
  METHODS
  The Rice-Vannucci model was adapted for neonatal HI injury in postnatal day 7 CD1 mice. SFKs activity in the postsynaptic densities was measured by Western blot. NMDAR tyrosine phosphorylation and their association with SFKs were determined by coimmunoprecipitation. Brains from animals treated with PP2 or its inactive analog, PP3, were examined histologically with cresyl violet and iron stain to assess the degree of damage.
  
  
  RESULTS
  Neonatal HI resulted in a rapid and transient increase in tyrosine phosphorylation of NMDAR subunits NR2A and NR2B. This upregulation correlated with the enhanced association of Fyn and Src with NR2A and NR2B. SFKs were activated in the postsynaptic densities after HI. Inhibition of SFKs with PP2 attenuated brain injury after neonatal HI, whereas PP3 did not protect the brain from the HI insult.
  
  
  CONCLUSIONS
  SFKs may play an important role in NMDAR-mediated excitotoxicity and downstream events leading to neuronal death after neonatal HI. Inhibition of SFKs may provide protection against neonatal stroke. Rather than blockade of NMDAR after HI in the developing brain, it may be safer and more beneficial to manipulate components of the NMDAR signaling complex at the postsynaptic density.
authors.affiliation: Department of Neurology, University of California San Francisco, San Francisco, CA 94143-0663, USA. xiangning.jiang@ucsf.edu
authors.forename: Xiangning
authors.initials: X
authors.lastname: Jiang
authors.forename: Dezhi
authors.initials: D
authors.lastname: Mu
authors.forename: Valerie
authors.initials: V
authors.lastname: Biran
authors.forename: Joel
authors.initials: J
authors.lastname: Faustino
authors.forename: Shengjun
authors.initials: S
authors.lastname: Chang
authors.forename: Christina M
authors.initials: CM
authors.lastname: Rincón
authors.forename: R Ann
authors.initials: RA
authors.lastname: Sheldon
authors.forename: Donna M
authors.initials: DM
authors.lastname: Ferriero
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D002545:Brain Ischemia / Q000188:drug therapy* / Q000378:metabolism* / Q000473:pathology; D004789:Enzyme Activation / Q000187:drug effects; D051379:Mice; D018696:Neuroprotective Agents / Q000008:administration & dosage; D011743:Pyrimidines / Q000008:administration & dosage*; D016194:Receptors, N-Methyl-D-Aspartate / Q000378:metabolism*; D015398:Signal Transduction / Q000187:drug effects; D016896:Treatment Outcome; D019061:src-Family Kinases / Q000008:administration & dosage* / Q000037:antagonists & inhibitors*
chemical_list: C412373:AG 1879; D018696:Neuroprotective Agents; D011743:Pyrimidines; D016194:Receptors, N-Methyl-D-Aspartate; D019061:src-Family Kinases