Modulation of haemocyte phagocytic and antibacterial activity by alpha-adrenergic receptor in scallop Chlamys farreri

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• 作者：Zhi Zhou ; Qiufeng Jiang ; Mengqiang Wang ; Feng Yue ; Lingling Wang ; Leilei Wang ; Fengmei Li ; Rui Liu ; Linsheng Song
• 关键词：¦Á-Adrenergic receptor ; Immunomodulation ; cAMP ; Haemocyte ; Scallop
• 刊名：Fish & Shellfish Immunology
• 出版年：2013
• 出版时间：September, 2013
• 年：2013
• 卷：35
• 期：3
• 页码：825-832
• 全文大小：1508 K

文摘

The adrenergic receptors are a class of G protein-coupled receptors, through which norepinephrine and epinephrine trigger the second messenger to modulate the immune response in immunocytes of vertebrate. In the present study, a gene coding the homologue of ¦Á-adrenergic receptor was identified from scallop Chlamys farreri (designated Cf¦ÁAR). Its deduced protein comprised 318 amino acids, and contained a conserved 7tm_1 domain. After Cf¦ÁAR protein was expressed in the HEK293 cells, the stimulation of octopamine, tyramine, epinephrine and isoprenaline (¦Â-adrenergic receptor agonist) did not change significantly the intracellular cAMP concentration, whereas the stimulation of norepinephrine and phenylephrine (¦Á-adrenergic receptor agonist) lowered significantly the cAMP level to 0.52 and 0.84?pmol ¦Ìl^?1 (P?<?0.05), respectively. The Cf¦ÁAR transcripts were ubiquitously detected in the tested tissues including haemocytes, adductor muscle, kidney, hepatopancreas, gill, gonad and mantle, with the highest expression in the gill. The expression level of Cf¦ÁAR mRNA decreased significantly (0.21-fold, P?<?0.05) at 3?h after the challenge of bacteria Vibrio anguillarum. Then, it began to increase (4.74-fold, P?<?0.05) at 12?h, and reached the highest level (4.92-fold, P?<?0.05) at 24?h after bacteria challenge. The addition of ¦Á-adrenergic receptor agonist to the primary scallop haemocytes repressed significantly the increase of phagocytic and antibacterial activity induced by LPS stimulation, while the induction was reverted by the addition of ¦Á-adrenergic receptor antagonist. These results collectively suggested that ¦Á-adrenergic receptor could be regulated dynamically in the transcriptional level during the immune response, and it could modulate the haemocyte phagocytic and antibacterial function through the second messenger cAMP, which might be requisite for pathogen elimination and the homeostasis maintenance in scallop.