Signaling Transduction Network Elucidation of ACE 2 Regulating <i>Apostichopus japonicus</i> Autolysis by Using Integrative TMT Proteomics and Transcriptomics

This study aims to reveal the transduction signaling network that triggers sea cucumber (<i>Apostichopus japonicus</i>) autolysis. The tandem mass tag (TMT) proteomics and transcriptomic techniques were used to analyze expression differences between inhibited and activated sea cucumber autolysis. Flow cytometry was used to identify apoptosis. Western blotting and RT-PCR verified the signaling pathway. The results showed that the angiotensin-converting enzyme 2 (ACE 2) activator (diminazene, DIZE) maintained the health of <i>A. japonicus</i>. The ACE 2 inhibitor (captopril, Capt) accelerated the autolysis. Based on the multiomics analysis, the ACE 2 activator activated the downstream NF-κB pathway to prevent the sea cucumber apoptosis. The Capt activated apoptosis initiation. Apoptosis occurred through the regulation of TNF and PI3K-Akt signaling pathways, which downregulate NF-κB. Akt was identified as an intermediate signaling protein downstream of ACE 2 that regulates autolysis in <i>A. japonicus</i>. Compared to <i>A. japonicus</i> in the ultraviolet-irradiated and Capt groups, the Akt inhibitor (perifosine, KRX) significantly reduced the expression of the PI3K-Akt and NF-κB pathways, thereby inhibiting the autolysis process. Additionally, DIZE attenuated ROS levels, thereby inhibiting the autolysis of <i>A. japonicus</i>. This study provides better insight into the autolysis mechanism of <i>A. japonicus</i>.