Characterization of Caspase8 and its role in the regulation of apoptosis-related genes in large yellow croaker (Larimichthys crocea)

The structure and function of Caspase8, a vital initiator caspase in apoptosis have been extensively studied in different species. However, the role of Caspase8 in Larimichthys crocea remains unknown. Therefore, the main aim of this study was to characterize Caspase8 in Larimichthys crocea and explore its role in the regulation of apoptosis-related genes. In this study, we molecularly characterized the full-length coding sequence of Caspase8 and investigated the role of Caspase8 in the regulation of apoptosis-related genes using qRT-PCR and western blot in Larimichthys crocea. Our results demonstrated that the gene and protein expression levels of Caspase8 were upregulated upon treatment with increasing levels of caspase activator (hydrogen peroxide, H2O2). Furthermore, activation of Caspase8 by birinapant significantly increased the mRNA expression of apoptosisrelated genes, and this effect was blocked by the knockdown of Caspase8 in hepatocytes. Also, palmitic acid (PA) and linoleic acid (LA) upregulated the transcription of apoptosis-related genes, but only PA induced apoptosis through Caspase8 in vivo and in vitro. Taken together, the findings of the present study will promote further exploration into the structure and function of Larimichthys crocea Caspase8 at the molecular level and indicate that the apoptosis system may be regulated by different fatty acids.