Suppression of serotonin N-acetyltransferase transcription and melatonin secretion from chicken pinealocytes transfected with Bmal1 antisense oligonucleotides containing locked nucleic acid in superfusion system

In birds, rhythmic changes in pineal serotonin N-acetyltransferase (arylalkylamine N-acetyltransferase, Aanat) transcripts are controlled by an oscillator located in the pinealocytes themselves which is comprised by clock genes. Our previous data indicated a temporal association between the expressions of chicken Bmal1 clock gene and Aanat suggesting a functional molecular link between them. Here, we studied the effect of cBmal1 antisense oligonucleotides containing locked nucleic acid on cAanat transcripts and melatonin production in cultured chicken pinealocytes transfected in superfusion system. These oligonucleotides synthesized for activating RNase H or blocking the binding of the translation machinery were able to reduce significantly cAanat transcription and melatonin secretion, whereas control inverted oligonucleotides were ineffective. These results indicate the key role of cBmal1 in the regulation of indole metabolism. The superfusion cell culture with reduced transfection toxicity may provide a useful tool for antisense drug design to influence the highly conserved clockwork also in man.