Activation of phosphatidylinositol-linked D1-like receptor modulates FGF-2 expression in astrocytes via IP3-dependent Ca2+ signaling

J Neurosci. 2009 Jun 17;29(24):7766-75. doi: 10.1523/JNEUROSCI.0389-09.2009.

Abstract

Fibroblast growth factor-2 (FGF-2) is predominantly synthesized and secreted by astrocytes in adult brain. Our previous study showed that activation of classical dopamine receptor D(1) or D(2) elicits FGF-2 biosynthesis and secretion in astrocytes. Here, we report that astrocytic FGF-2 expression is also regulated by phosphatidylinositol (PI)-linked D(1)-like receptor. SKF83959, a selective PI-linked D(1)-like receptor agonist, upregulates the levels of FGF-2 protein in striatal astrocyte cultures in classical dopamine D(1) and D(2) receptor-independent manner. The conditional medium derived from SKF83959-activated astrocytes promoted the number of TH(+) neurons in vitro. Treatment of astrocytes with SKF83959 increased intracellular calcium in two phases. Inhibition of intracellular calcium oscillation by inositol 1,4,5-triphosphate (IP3) inhibitors blocked the SKF83959-induced increase in FGF-2 expression. Moreover, intraperitoneal administration of SKF83959 reversed l-methyl-4-phenyl-l,2,3,6-tetrahydropypridine (MPTP)-induced reduction in FGF-2 expression in both the striatum and ventral midbrain and resulted in marked protection of dopaminergic neurons from MPTP-induced neurotoxicity. These results indicate that IP3/Ca(2+)/calmodulin-dependent protein kinase is an uncharted intracellular signaling pathway that is crucial for the regulation of FGF-2 synthesis in astrocytes. PI-linked D(1)-like receptor plays an important role in the regulation of astrocytic FGF-2 expression and neuroprotection which may provide a potential target for the drug discovery in Parkinson's disease.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine / pharmacology
  • 2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-benzazepine / analogs & derivatives
  • 2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-benzazepine / pharmacology
  • Animals
  • Animals, Newborn
  • Astrocytes / drug effects
  • Astrocytes / physiology*
  • Benzazepines / pharmacology
  • Calcium Signaling / drug effects
  • Calcium Signaling / physiology*
  • Cells, Cultured
  • Culture Media, Conditioned / chemistry
  • Dopamine Agonists / pharmacology
  • Dopamine Antagonists / pharmacology
  • Dose-Response Relationship, Drug
  • Drug Interactions
  • Embryo, Mammalian
  • Enzyme Inhibitors / pharmacology
  • Fibroblast Growth Factor 2 / metabolism*
  • Gene Expression Regulation / drug effects
  • Inositol 1,4,5-Trisphosphate / metabolism*
  • Mesencephalon / cytology
  • Mice
  • Mice, Inbred C57BL
  • Neurons / physiology
  • Neurotoxins / pharmacology
  • Phosphatidylinositols / metabolism*
  • Rats
  • Rats, Sprague-Dawley
  • Receptors, Dopamine D1 / physiology*
  • Tyrosine 3-Monooxygenase / metabolism

Substances

  • Benzazepines
  • Culture Media, Conditioned
  • Dopamine Agonists
  • Dopamine Antagonists
  • Enzyme Inhibitors
  • Neurotoxins
  • Phosphatidylinositols
  • Receptors, Dopamine D1
  • SCH 23390
  • Fibroblast Growth Factor 2
  • 2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-benzazepine
  • SK&F 83959
  • Inositol 1,4,5-Trisphosphate
  • 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine
  • Tyrosine 3-Monooxygenase