Open AccessInhibition of GADD34, the Stress-Inducible Regulatory Subunit of the Endoplasmic Reticulum Stress Response, Does Not Enhance Functional Recovery after Spinal Cord Injury
Author(s) -
Sujata Saraswat Ohri,
Ashley Mullins,
Michał Hetman,
Scott R. Whittemore
Publication year - 2014
Publication title -
plos one
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.99
H-Index - 332
ISSN - 1932-6203
DOI - 10.1371/journal.pone.0109703
Subject(s) - guanabenz , endoplasmic reticulum , unfolded protein response , microbiology and biotechnology , integrated stress response , pharmacology , chop , oligodendrocyte , spinal cord injury , neurodegeneration , neuroprotection , biology , neuroscience , medicine , spinal cord , central nervous system , agonist , biochemistry , receptor , disease , translation (biology) , messenger rna , gene , myelin
Activation of the endoplasmic reticulum stress response (ERSR) is a hallmark of various pathological diseases and/or traumatic injuries. Restoration of ER homeostasis can contribute to improvement in the functional outcome of these diseases. Using genetic and pharmacological inhibition of the PERK-CHOP arm of the ERSR, we recently demonstrated improvements in hindlimb locomotion after spinal cord injury (SCI) and implicated oligodendrocyte survival as a potential mechanism. Here, we investigated the contribution of stress-inducible PPP1R15A/GADD34, an ERSR signaling effector downstream of CHOP that dephosphorylates eIF2α, in the pathogenesis of SCI. We show that although genetic ablation of GADD34 protects oligodendrocyte precursor cells (OPCs) against ER stress-mediated cell death in vitro and results in differential ERSR attenuation in vivo after SCI, there is no improvement in hindlimb locomotor function. Guanabenz, a FDA approved antihypertensive drug, was recently shown to reduce the burden of misfolded proteins in the ER by directly targeting GADD34. Guanabenz protected OPCs from ER stress-mediated cell death in vitro and attenuated the ERSR in vivo after SCI. However, guanabenz administration failed to rescue the locomotor deficits after SCI. These data suggest that deletion of GADD34 alone is not sufficient to improve functional recovery after SCI.