The Function Of PLC-β In The Regulation Of Gut Microbiota Homeostasis

The phospholipid signaling pathway is one of the main systems of cellular signal transduction.This signaling can be activated by environment stress and pathogen attack.As a key enzyme in the phospholipid signaling pathway,phospholipase C-β（PLC-β）occupies an indispensable position in this pathway.We identified a PLC-β in kuruma shrimp Marsupenaeus japonicus.The PLC-β was upregulated in shrimp challenged by Vibrio anguillarum.After knockdown of Plc-β,the bacterial load in gastrointestinal tract was increased significantly.Further study found that in addition to regulate ROS production,PLC-β was also involved in regulation of antimicrobial peptide expression to maintain homeostasis of gut microbiaota.Mechanical analysis found that a G protein-coupled receptor（GPCR）recognized invading bacteria and transmit the signal to PLC-β for its activation.The activated PLC-β produce inositol 1,4,5trisphosphate（IP3）to promote the release of calcium ions（Ca2+）to cytoplasm.Ca2+activates dual oxidases（DUOX）on the cell membrane to produce reactive oxygen species（ROS）against bacteria.Ca2+ can also bind and activate calmodulin（CaM）,and eventually form a Ca2+calmodulin-calcium protein kinase（Ca2+-CaM-CaMK）complex,which further interacted and activated the transforming growth factor β-activated kinase 1（TAK1）and IKK-β and IKK-y in the immune deficiency（IMD）pathway resulting in the transcription factor RELISH into the nucleus to regulate antimicrobial peptide（AMP）expression.Taken together,shrimp PLC-βexerts its antibacterial effect in gut microbiota homeostasis by regulating AMP expression through the atypic IMD pathway in addition to regulation ROS production.