Activation of UTP-sensitive P 2 Y 2 receptor induces the expression of cholinergic genes in cultured cortical neurons : A signaling cascade triggered by Ca 2 + mobilization and ERK phosphorylation

The number of text pages: 39 The number of tables: 0 The number of figures: 7 The number of supplementary figures: 4 The number of references: 55 The number of words in the Abstract: 207 The number of words in the Introduction: 528 The number of words in the Discussion: 1497 Abstract Adenosine 5'-triphosphate (ATP) functions as an extracellular signaling molecule that is co-stored and co-released with neurotransmitters at central and peripheral neuronal synapses. Stimulation by ATP up-regulates the expression of synaptic genes in muscle – including the genes for nicotine acetylcholine receptor (α-, δ-and ε-subunits) and acetylcholinesterase (AChE) – via the P2Y receptor (P2YR), but the trophic response of neurons to the activation of P2YRs is less well understood. We reported that cultured cortical neurons and the developing rat brain expressed different types of P2YRs, and among these the UTP-sensitive P2Y 2 R was the most abundant. P2Y 2 R was found to exist in membrane rafts and it co-localized with the post-synaptic protein PSD-95 in cortical neurons. Notably, agonist-dependent stimulation of P2Y 2 R elevated the neuronal expression of cholinergic genes encoding AChE, PRiMA (an anchor for the globular form AChE) and choline acetyltransferase, and this induction was mediated by a signaling cascade that involved Ca 2+ mobilization and ERK1/2 activation. The importance of P2Y 2 R action was further shown by the receptor's synergistic effect with P2Y 1 R in enhancing cholinergic gene expression via the robust stimulation of Ca 2+ influx. Taken together our results revealed a developmental function of P2Y 2 R in promoting synaptic gene expression and demonstrate the influence of co-stimulation of P2Y 1 R and P2Y 2 R in neurons. This article has not been copyedited and formatted. The final version may differ from this version.