TY - JOUR
T1 - Calcineurin inhibition enhances motor neuron survival following injury
AU - Hui, Kelvin K.W.
AU - Liadis, Nicole
AU - Robertson, Jennifer
AU - Kanungo, Anish
AU - Henderson, Jeffrey T.
PY - 2010/3
Y1 - 2010/3
N2 - The immunosuppressive agents cyclosporin A (CsA) and FK-506 have previously been shown to exhibit neurotrophic and neuroprotective properties in vivo. Given that significant clinical expertise exists for both drugs, they represent an attractive starting point for treatment of acute neural injuries. One putative mechanism for neuroprotection by these drugs relates to inhibition of calcineurin activity. However each drug-immunophilin complex can potentially influence additional signal transduction pathways. Furthermore, several non-immunosuppressive immunophilin ligands have been described as possessing neuroprotective properties, suggesting that neuroprotection may be separable from calcineurin inhibition. In the present study, we examined the mechanism of this neuroprotection in facial motor neurons following axotomy-induced injury. Similar to previous studies in rats, CsA and FK-506 enhanced motor neuron survival in mice following acute injury. To examine the mechanism responsible for neuroprotection by these agents, pharmacologic inhibitors of several potential alternate signalling pathways (17-(allylamino)-17-demethoxygeldanamycin, rapamycin, cypermethrin) were evaluated with respect to neuroprotection. Of these, only cypermethrin, a direct calcineurin inhibitor not previously associated with neuronal survival properties, was observed to significantly enhance motor neuron survival following injury. The results demonstrate for the first time that direct inhibition of calcineurin is neuroprotective in vivo. These data support a model in which calcineurin inhibition promotes neuronal survival, distinct from effects upon neurite outgrowth.
AB - The immunosuppressive agents cyclosporin A (CsA) and FK-506 have previously been shown to exhibit neurotrophic and neuroprotective properties in vivo. Given that significant clinical expertise exists for both drugs, they represent an attractive starting point for treatment of acute neural injuries. One putative mechanism for neuroprotection by these drugs relates to inhibition of calcineurin activity. However each drug-immunophilin complex can potentially influence additional signal transduction pathways. Furthermore, several non-immunosuppressive immunophilin ligands have been described as possessing neuroprotective properties, suggesting that neuroprotection may be separable from calcineurin inhibition. In the present study, we examined the mechanism of this neuroprotection in facial motor neurons following axotomy-induced injury. Similar to previous studies in rats, CsA and FK-506 enhanced motor neuron survival in mice following acute injury. To examine the mechanism responsible for neuroprotection by these agents, pharmacologic inhibitors of several potential alternate signalling pathways (17-(allylamino)-17-demethoxygeldanamycin, rapamycin, cypermethrin) were evaluated with respect to neuroprotection. Of these, only cypermethrin, a direct calcineurin inhibitor not previously associated with neuronal survival properties, was observed to significantly enhance motor neuron survival following injury. The results demonstrate for the first time that direct inhibition of calcineurin is neuroprotective in vivo. These data support a model in which calcineurin inhibition promotes neuronal survival, distinct from effects upon neurite outgrowth.
KW - Apoptosis
KW - Facial nerve
KW - Immunophilin ligands
KW - Mice
KW - Neuronal survival
KW - Programmed cell death
UR - http://www.scopus.com/inward/record.url?scp=77953495143&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=77953495143&partnerID=8YFLogxK
U2 - 10.1111/j.1582-4934.2009.00715.x
DO - 10.1111/j.1582-4934.2009.00715.x
M3 - Article
C2 - 19243469
AN - SCOPUS:77953495143
SN - 1582-1838
VL - 14
SP - 671
EP - 686
JO - Journal of Cellular and Molecular Medicine
JF - Journal of Cellular and Molecular Medicine
IS - 3
ER -