title: Pleiotrophin is a neurotrophic factor for spinal motor neurons.
abstract: Regeneration in the peripheral nervous system is poor after chronic denervation. Denervated Schwann cells act as a "transient target" by secreting growth factors to promote regeneration of axons but lose this ability with chronic denervation. We discovered that the mRNA for pleiotrophin (PTN) was highly up-regulated in acutely denervated distal sciatic nerves, but high levels of PTN mRNA were not maintained in chronically denervated nerves. PTN protected spinal motor neurons against chronic excitotoxic injury and caused increased outgrowth of motor axons out of the spinal cord explants and formation of "miniventral rootlets." In neonatal mice, PTN protected the facial motor neurons against cell death induced by deprivation from target-derived growth factors. Similarly, PTN significantly enhanced regeneration of myelinated axons across a graft in the transected sciatic nerve of adult rats. Our findings suggest a neurotrophic role for PTN that may lead to previously unrecognized treatment options for motor neuron disease and motor axonal regeneration.
authors.affiliation: Departments of Neurology and Neuroscience, Johns Hopkins University School of Medicine, 600 North Wolfe Street, Baltimore, MD 21287, USA.
authors.forename: Ruifa
authors.initials: R
authors.lastname: Mi
authors.forename: Weiran
authors.initials: W
authors.lastname: Chen
authors.forename: Ahmet
authors.initials: A
authors.lastname: Höke
mesh_terms: D000077548:Anaplastic Lymphoma Kinase; D000818:Animals; D002352:Carrier Proteins / Q000502:physiology*; D016207:Cytokines / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D009046:Motor Neurons / Q000378:metabolism*; D009414:Nerve Growth Factors / Q000378:metabolism*; D009416:Nerve Regeneration; D011505:Protein-Tyrosine Kinases / Q000378:metabolism; D051381:Rats; D020794:Receptor Protein-Tyrosine Kinases; D012583:Schwann Cells / Q000378:metabolism; D012584:Sciatic Nerve / Q000378:metabolism; D013116:Spinal Cord / Q000378:metabolism*
chemical_list: D002352:Carrier Proteins; D016207:Cytokines; D009414:Nerve Growth Factors; C066845:pleiotrophin; D000077548:Anaplastic Lymphoma Kinase; D011505:Protein-Tyrosine Kinases; D020794:Receptor Protein-Tyrosine Kinases