Functions of Forkhead Box O on Glucose Metabolism in Abalone Haliotis discus hannai and Its Responses to High Levels of Dietary Lipid

Abstract

The forkhead box O (FoxO) subfamily is a member of the forkhead transcription factor family. It has regulation functions in glucose metabolism in mammals and fish. In the present study, a gene of the foxo homolog in abalone Haliotis discus hannai was cloned. A conservative forkhead (FH) domain and a transactivation (FoxO-TAD) domain were identified. Abalone foxo-specific siRNA (small interfering RNA) was injected to investigate the functions of foxo on glucose metabolism. Knockdown of foxo inhibited expression of phosphoenolpyruvate carboxykinase (pepck) and significantly increased expressions of hexokinase (hk) and pyruvate kinase (pk), but it failed to inhibit the relative mRNA level of glucose-6-phosphatase (g6pase). Then, a 100-day feeding trial was conducted to investigate the response of foxo and glucose metabolism in abalone fed with 1.57% (LFD, low-fat diet), 3.82% (MFD, middle-fat diet) and 6.72% (HFD, high-fat diet) of dietary lipid, respectively. The insulin-signaling pathway (AKT) was depressed and FoxO was activated by the HFD, but it did not inhibit glycolysis (hk) or improved gluconeogenesis significantly (pepck and g6pase). At the same time, impaired hepatopancreas glycogen storage raised hemolymph glucose levels. In conclusion, abalone foxo can be regulated by dietary lipid and can regulate gluconeogenesis or glycolysis in response to changes of dietary lipid levels, in which glycogen metabolism plays an important role.

Arginine Regulates TOR Signaling Pathway through SLC38A9 in Abalone Haliotis discus hannai

“…The method of slc38a9 cloning was referred to Wang et al [34]. The mRNA sequence of slc38a9 was obtained from the transcriptome database (unpublished data), and the primers were designed by Oligo 7 software (Molecular Biology Insights, Inc., Colorado Springs, CO) and synthesized by Sangon Biotech (Shanghai, China) (Table 1).…”

“…Six abalones were used for the tissue distribution analysis of slc38a9, the expression levels of slc38a9 in seven tissues (hemolymph, muscle, mental, gill, intestine, gonad and digestive gland) of abalone were detected by quantitative real-time PCR. The sequence of negative control siRNA (siRNA-NC) and synthesis of siRNA was conducted by Wang et al [34]. Four siRNAs (siRNA-108, siRNA-236, siRNA-347 and siRNA-469) targeting different encoding regions of slc38a9 were designed by BLOCK-iT™ RNAi Designer (Available online: http://rnaidesigner.thermofisher.com/rnaiexpress/, accessed on 20 May 2020) (Table 2).…”

ChIP-seq identifies McSLC35E2 as a novel target gene of McNrf2 in Mytilus coruscus, highlighting its role in the regulation of oxidative stress response in marine mollusks

“…Indeed, the most important role of Nrf2 target genes lies in their contribution to the antioxidant defense system and their ability to mitigate oxidative damage. Nrf2 target genes ensure cell integrity and overall health in the face of oxidative challenges by upregulating antioxidant enzymes and detoxifying proteins (Wang et al, 2021b). Unfortunately, studies of Nrf2 and its target genes have been more extensive in humans and mammals, but there has been very limited reporting in aquatic organisms, especially bivalve mollusks.…”

Comprehensive Comparison of Effects of Antioxidant (Astaxanthin) Supplementation from Different Sources in Haliotis discus hannai Diet

“…Pacific abalone , Haliotis discus hannai , is a common economic shellfish that possesses a high nutritional and medicinal value [ 17 , 18 ]. It is the most populous species of farmed abalone around the world and is mostly cultured in China.…”