ZPK/DLK, a mitogen-activated protein kinase kinase kinase, is a critical mediator of programmed cell death of motoneurons

Aki Itoh, Makoto Horiuchi, Kouji Wakayama, Jie Xu, Peter Bannerman, David E Pleasure, Takayuki Ito

Research output: Contribution to journalArticle

27 Citations (Scopus)

Abstract

Activation of mitogen-activated protein kinase pathways is critically involved in naturally occurring programmed cell death of motoneurons during development, but the upstream mediators remain undetermined. We found that mice deficient in ZPK, also called DLK (ZPK/DLK), an upstream kinase in these pathways, have twice as many spinal motoneurons as do their wild-type littermates. Nuclear HB9/MNX1-positive motoneuron pools were generated similarly in the spinal cord of both ZPK/DLK-deficient and wild-type embryos. Thereafter, however, significantly less apoptotic motoneurons were found in ZPK/DLK-deficient embryos compared with wild-type embryos, resulting in retention of excess numbers of motoneurons after birth. Notably, these excess motoneurons remained viable without atrophic changes in the ZPK/DLK-deficient mice surviving into adulthood. Analysis of the diaphragm and the phrenic nerve revealed that clustering and innervation of neuromuscular junctions were indistinguishable between ZPK/DLK-deficient and wild-type mice, whereas the proximal portion of the phrenic nerve of ZPK/DLK-deficient mice contained significantly more axons than the distal portion. This result supports the hypothesis that some excess ZPK/DLK-deficient motoneurons survived without atrophy despite failure to establish axonal contact with their targets. This study provides compelling evidence for a critical role for ZPK/DLK in naturally occurring programmed cell death of motoneurons and suggests that ZPK/DLK could become a strategic therapeutic target in motor neuron diseases in which aberrant activation of the apoptogenic cascade is involved.

Original languageEnglish (US)
Pages (from-to)7223-7228
Number of pages6
JournalJournal of Neuroscience
Volume31
Issue number20
DOIs
StatePublished - May 18 2011

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MAP Kinase Kinase Kinases
Motor Neurons
Cell Death
Phrenic Nerve
Embryonic Structures
Motor Neuron Disease
Neuromuscular Junction
Diaphragm
Mitogen-Activated Protein Kinases
Atrophy
Cluster Analysis
Axons
Spinal Cord
Phosphotransferases
Parturition

ASJC Scopus subject areas

  • Neuroscience(all)

Cite this

ZPK/DLK, a mitogen-activated protein kinase kinase kinase, is a critical mediator of programmed cell death of motoneurons. / Itoh, Aki; Horiuchi, Makoto; Wakayama, Kouji; Xu, Jie; Bannerman, Peter; Pleasure, David E; Ito, Takayuki.

In: Journal of Neuroscience, Vol. 31, No. 20, 18.05.2011, p. 7223-7228.

Research output: Contribution to journalArticle

Itoh, Aki ; Horiuchi, Makoto ; Wakayama, Kouji ; Xu, Jie ; Bannerman, Peter ; Pleasure, David E ; Ito, Takayuki. / ZPK/DLK, a mitogen-activated protein kinase kinase kinase, is a critical mediator of programmed cell death of motoneurons. In: Journal of Neuroscience. 2011 ; Vol. 31, No. 20. pp. 7223-7228.
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