Muscarinic acetylcholine receptors induce the expression of the immediate early growth regulatory gene CYR61

In brain, muscarinic acetylcholine receptors (mAChRs) modulate neuronal fun ctions including long term potentiation and synaptic plasticity in neuronal circuits that are involved in learning and memory formation. To identify m AChR-inducible genes, we used a differential display approach and found tha t mAChRs rapidly induced transcription of the immediate early gene CYR61 in HEK 293 cells with a maximum expression after 1 h of receptor stimulation. CYR61 is a member of the emerging CCN gene family that includes CYR61/CEF1 0, CTGF/FISP-12, and NOV; these encode secretory growth regulatory proteins with distinct functions in cell proliferation, migration, adhesion, and su rvival. We found that CYR61, CTGF, and NOV were expressed throughout the hu man central nervous system. Stimulation of mAChRs induced CYR61 expression in primary neurons and rat brain where CYR61 mRNA was detected in cortical layers V and VI and in thalamic nuclei. In contrast, CTGF and NOV expressio n was not altered by mAChRs neither in neuronal tissue culture nor rat brai n. Receptor subtype analyses demonstrated that mi and m3 mAChR subtypes str ongly induced CYR61 expression, whereas m2 and m4 mAChRs had only subtle ef fects. Increased CYR61 expression was coupled to mAChRs by both protein kin ase C and elevations of intracellular Ca2+. Our results establish that CYR6 1 expression in mammalian brain is under the control of cholinergic neurotr ansmission; it may thus be involved in cholinergic regulation of synaptic p lasticity.