title: Protecting motor neurons from toxic insult by antagonism of adenosine A2a and Trk receptors.
abstract: The death of motor neurons in amyotrophic lateral sclerosis (ALS) is thought to result from the interaction of a variety of factors including excitotoxicity, accumulation of toxic proteins, and abnormal axonal transport. Previously, we found that the susceptibility of motor neurons to excitotoxic insults can be limited by inhibiting signals evoked by brain-derived neurotrophic factor (BDNF) activation of the receptor tyrosine kinase B (TrkB). Here we show that this can be achieved by direct kinase inhibition or by blockade of a transactivation pathway that uses adenosine A2a receptors and src-family kinases (SFKs). Downstream signaling cascades (such as mitogen-activated protein kinase and phosphatidylinositol-3 kinase) are inhibited by these blockers. In addition to protecting motor neurons from excitotoxic insult, these agents also prevent toxicity that follows from the expression of mutant proteins (G85R superoxide dismutase 1; G59S p150(glued)) that cause familial motor neuron disease. TrkB, adenosine A2a receptors, and SFKs associate into complexes in lipid raft and nonlipid raft membranes and the signaling from lipids rafts may be particularly important because their disruption by cholesterol depletion blocks the ability of BDNF to render motor neurons vulnerable to insult. The neuroprotective versatility of Trk antagonism suggests that it may have broad utility in the treatment of ALS patients.
authors.affiliation: Department of Neurology, Children's Hospital of Philadelphia, Joseph Stokes Jr. Research Institute, Philadelphia, Pennsylvania 19104, USA.
authors.forename: Jelena
authors.initials: J
authors.lastname: Mojsilovic-Petrovic
authors.forename: Goo-Bo
authors.initials: GB
authors.lastname: Jeong
authors.forename: Amanda
authors.initials: A
authors.lastname: Crocker
authors.forename: Amrita
authors.initials: A
authors.lastname: Arneja
authors.forename: Samuel
authors.initials: S
authors.lastname: David
authors.forename: David S
authors.initials: DS
authors.lastname: Russell
authors.forename: David
authors.initials: D
authors.lastname: Russell
authors.forename: Robert G
authors.initials: RG
authors.lastname: Kalb
mesh_terms: D058917:Adenosine A2 Receptor Antagonists; D000690:Amyotrophic Lateral Sclerosis / Q000139:chemically induced / Q000378:metabolism* / Q000473:pathology / Q000517:prevention & control; D000818:Animals; D019208:Brain-Derived Neurotrophic Factor / Q000378:metabolism*; D002478:Cells, Cultured; D007608:Kainic Acid; D009046:Motor Neurons / Q000187:drug effects / Q000378:metabolism* / Q000473:pathology*; D018696:Neuroprotective Agents / Q000008:administration & dosage; D051381:Rats; D017207:Rats, Sprague-Dawley; D020794:Receptor Protein-Tyrosine Kinases / Q000037:antagonists & inhibitors* / Q000378:metabolism; D043705:Receptor, Adenosine A2A / Q000378:metabolism
chemical_list: D058917:Adenosine A2 Receptor Antagonists; D019208:Brain-Derived Neurotrophic Factor; D018696:Neuroprotective Agents; D043705:Receptor, Adenosine A2A; D020794:Receptor Protein-Tyrosine Kinases; D007608:Kainic Acid