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Upregulation of axon guidance molecules in the adult central nervous system of Nogo‐ A knockout mice restricts neuronal growth and regeneration
Author(s) -
Kempf Anissa,
Montani Laura,
Petrinovic Marija M.,
Schroeter Aileen,
Weinmann Oliver,
Patrignani Andrea,
Schwab Martin E.
Publication year - 2013
Publication title -
european journal of neuroscience
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.346
H-Index - 206
eISSN - 1460-9568
pISSN - 0953-816X
DOI - 10.1111/ejn.12357
Subject(s) - downregulation and upregulation , knockout mouse , axon , regeneration (biology) , central nervous system , neuroscience , microbiology and biotechnology , nervous system , biology , receptor , genetics , gene
Adult central nervous system axons show restricted growth and regeneration properties after injury. One of the underlying mechanisms is the activation of the Nogo‐A/Nogo receptor (NgR1) signaling pathway. Nogo‐A knockout ( KO ) mice show enhanced regenerative growth in vivo , even though it is less pronounced than after acute antibody‐mediated neutralization of Nogo‐A. Residual inhibition may involve a compensatory component. By mRNA expression profiling and immunoblots we show increased expression of several members of the Ephrin/Eph and Semaphorin/Plexin families of axon guidance molecules, e.g. EphrinA3 and EphA4, in the intact spinal cord of adult Nogo‐A KO vs. wild‐type ( WT ) mice. EphrinA3 inhibits neurite outgrowth of EphA4‐positive neurons in vitro . In addition, EphrinA3 KO myelin extracts are less growth‐inhibitory than WT but more than Nogo‐A KO myelin extracts. EphA4 KO cortical neurons show decreased growth inhibition on Nogo‐A KO myelin as compared with WT neurons, supporting increased EphA4‐mediated growth inhibition in Nogo‐A KO mice. Consistently, in vivo , Nogo‐A/EphA4 double KO mice show increased axonal sprouting and regeneration after spinal cord injury as compared with EphA4 KO mice. Our results reveal the upregulation of developmental axon guidance cues following constitutive Nogo‐A deletion, e.g. the EphrinA3/EphA4 ligand/receptor pair, and support their role in restricting neurite outgrowth in the absence of Nogo‐A.