The simple neuroendocrine-immune regulatory network in oyster Crassostrea gigas mediates complex functions

Abstract

The neuroendocrine-immune (NEI) regulatory network is a complex system, which plays an indispensable role in the immunity of the host. In the present study, the bioinformatical analysis of the transcriptomic data from oyster Crassostrea gigas and further biological validation revealed that oyster TNF (CgTNF-1 CGI_10018786) could activate the transcription factors NF-κB and HSF (heat shock transcription factor) through MAPK signaling pathway, and then regulate apoptosis, redox reaction, neuro-regulation and protein folding in oyster haemocytes. The activated immune cells then released neurotransmitters including acetylcholine, norepinephrine and [Met5]-enkephalin to regulate the immune response by arising the expression of three TNF (CGI_10005109, CGI_10005110 and CGI_10006440) and translocating two NF-κB (Cgp65, CGI_10018142 and CgRel, CGI_10021567) between the cytoplasm and nuclei of haemocytes. Neurotransmitters exhibited the immunomodulation effects by influencing apoptosis and phagocytosis of oyster haemocytes. Acetylcholine and norepinephrine could down-regulate the immune response, while [Met5]-enkephalin up-regulate the immune response. These results suggested that the simple neuroendocrine-immune regulatory network in oyster might be activated by oyster TNF and then regulate the immune response by virtue of neurotransmitters, cytokines and transcription factors.

First indication of acetylcholine-based communication in honeybee haemocytes and its modulation by a neonicotinoid insecticide

“…It has been experimentally shown that neonicotinoids drastically decrease haemocyte numbers in the haemolymph of honeybees and also inhibit their ability to mount an effective immune response within 24 h of exposure 8 . In molluscs, the blocking of haemocyte-based mAChR before pathogen challenge promotes the expression of Tumor Necrosis Factor (TNF), which in turn results in elevated haemocyte apoptosis 21,31 . If a similar, nAChR -based, regulatory connection is present in the haemocytes of pollinators, nAChR blockage by neonicotinoids could directly explain their detrimental effects on haemocytes and by extension the immunosuppressive effects observed in honeybees 7 .…”

CgA1AR-1 acts as an alpha-1 adrenergic receptor in oyster Crassostrea gigas mediating both cellular and humoral immune response

“…Fluo-3 AM fluorescent probe (Beyotime, 1.0 µmol L -1 ) was employed in the examination of intracellular Ca 2+ , and the cAMP Direct Immunoassay Kit (ab65355, Abcam, Cambridge, UK) was used to measure cAMP concentration as illustrated [34].…”

Transcriptomic analysis of oyster Crassostrea gigas larvae illustrates the response patterns regulated by catecholaminergic system upon acute heat and bacterial stress

“…For example, there were enriched GO terms of both monooxygenase activity and dopamine beta-monooxygenase activity in all the Bacteria, Heat and Bacterial+Heat groups. Previous reports have revealed that neuroendocrine regulation is crucial for the responses to external and internal adverse stress in molluscs (Liu et al, 2016a;Liu et al, 2016b;Liu et al, 2015a;Liu et al, 2015b). And CAs are one of the very first appeared neurotransmitters during the ontogenesis of mollusc larvae, and act at the earliest developmental stages as signals influencing cell proliferation, differentiation, and neuritogenesis in different molluscs (Ottaviani, 2011;Ottaviani and Franceschi, 1996).…”

“…CAs were discovered at the beginning of the 20th century and consist of dopamine (DA), norepinephrine (NE) and epinephrine (E) (Kvetnansky et al, 2009;Sabban and Kvetnansky, 2001). In the past decades, CAs, together with their receptors and metabolic enzymes, have been identified in molluscs including bivalves, gastropods, etc (Liu et al, 2016a;Zhou et al, 2011a;Zhou et al, 2012;Zhou et al, 2011b;Zhou et al, 2011c;Zhou et al, 2011d;Zhou et al, 2011f). Previous studies reported that stress could induce the synthesis and release of CAs in molluscs.…”