Mitogen-activated protein kinase mediates purinergic-enhanced nerve growth factor-induced neurite outgrowth in PC12 cells

Holger Peter Behrsing, Philip R Vulliet

Research output: Contribution to journalArticle

18 Scopus citations

Abstract

In 1999, we reported new observations that several compounds, including ATP, enhance neurite expression in PC12 cells when coapplied with nerve growth factor (NGF). Because purinergic and NGF signaling have several potential interfaces in PC12 cells, a series of experiments was conducted to elucidate the signal mediators contributing to the enhancement. Activities of selected kinases were measured and Western blots evaluated mitogen-activated protein kinase (MAPK) active and non-active isoforms in lysates of the treated PC12 cells. In terms of purinergic potency, ATP and β,γ-methylene ATP elicited the greatest neurite-enhancing effect, whereas adenosine and α,β-methylene ATP elicited the smallest. The effectiveness of a nonhydrolyzable analog such as β,γ-methylene ATP indicates that a nonmetabolic process is responsible. In response to ATP, NGF, or NGF + ATP, MAPK activity (measured by 32P incorporation) was maximal within 2 hr and remained statistically elevated over control levels throughout the 24 hr monitored. At maximal 32P incorporation, MAPK activity in response to ATP, NGF, and NGF + ATP was two-, four-, and sixfold higher, respectively, than control values; the observed increase was qualitatively confirmed using Western blots. Short-term inhibition experiments with protein kinase C and MAPK indicated that MAPK transduces the enhancing signal. We conclude from these experiments that ATP coapplied with NGF increases PC12 neurite expression by elevation of MAPK activity, likely by P2 receptor activation, and suggest that combination therapies with NGF and its enhancing adjunct compounds may be plausible for certain degenerative neurological disorders.

Original languageEnglish (US)
Pages (from-to)64-74
Number of pages11
JournalJournal of Neuroscience Research
Volume78
Issue number1
DOIs
StatePublished - Oct 1 2004

Keywords

  • Kinase
  • MAPK
  • Neurite outgrowth
  • NGF
  • Purinergic

ASJC Scopus subject areas

  • Neuroscience(all)

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