Regulatory mechanism of Elovl6 in lipid metabolism, antioxidant capacity, and immune function in Scylla paramamosain revealed by Ap-1

Abstract

In mammals, elongation of very long-chain fatty acids protein 6 (ELOVL6) play a role in both the elongation of fatty acids and the development of associated inflammation. However, the function and transcriptional regulatory mechanisms of Elovl6 in invertebrates are poorly understood. This study aimed to examine the function of Elovl6 and its transcriptional regulatory mechanism in Scylla paramamosain. RNA interference experiments showed that elovl6 knockdown significantly affected the synthesis and catabolism of hepatopancreatic lipids, leading to an increase in triglyceride levels and saturated fatty acid content, and a decrease in polyunsaturated fatty acid content. Notably, antioxidant capacity and immune function were also impaired, with decreased activity of antioxidant enzymes and immune-related genes. To investigate the transcription regulation of elovl6, a 2212-bp promoter fragment upstream of elovl6 was cloned and characterized. Analysis of the luciferase reporter showed that Ap-1 regulates elovl6 transcription via the −353 to −343 binding site. In vivo injection of the Ap-1 inhibitor T-5224 verified its inhibitory effect on elovl6 expression, with results similar to those of elovl6 knockdown, indicating that Ap-1 regulates lipid metabolism, antioxidant capacity, and immune function via Elovl6.