Transcriptomically Revealed Oligo-Fucoidan Enhances the Immune System and Protects Hepatocytes via the ASGPR/STAT3/HNF4A Axis

Abstract

Oligo-fucoidan, a sulfated polysaccharide extracted from brown seaweed, exhibits anti-inflammatory and anti-tumor effects. However, the knowledge concerning the detailed mechanism of oligo-fucoidan on liver cells is obscure. In this study, we investigate the effect of oligo-fucoidan in normal hepatocytes by transcriptomic analysis. Using an oligo-fucoidan oral gavage in wild-type adult zebrafish, we find that oligo-fucoidan pretreatment enhances the immune system and anti-viral genes in hepatocytes. Oligo-fucoidan pretreatment also decreases the expression of lipogenic enzymes and liver fibrosis genes. Using pathway analysis, we identify hepatocyte nuclear factor 4 alpha (HNF4A) to be the potential driver gene. We further investigate whether hepatocyte nuclear factor 4 alpha (HNF4A) could be induced by oligo-fucoidan and the underlying mechanism. Therefore, a normal hepatocyte clone 9 cell as an in vitro model was used. We demonstrate that oligo-fucoidan increases cell viability, Cyp3a4 activity, and Hnf4a expression in clone 9 cells. We further demonstrate that oligo-fucoidan might bind to asialoglycoprotein receptors (ASGPR) in normal hepatocytes through both in vitro and in vivo competition assays. This binding, consequently activating the signal transducer and activator of transcription 3 (STAT3), increases the expression of the P1 isoform of HNF4A. According to our data, we suggest that oligo-fucoidan not only enhances the gene expression associated with anti-viral ability and immunity, but also increases P1-HNF4A levels through ASGPR/STAT3 axis, resulting in protecting hepatocytes.

Low molecular weight fucoidan inhibits hepatocarcinogenesis and nonalcoholic fatty liver disease in zebrafish via ASGR/STAT3/HNF4A signaling

“…There is a significant increase of ccne1 for wild‐type treated OF (WT+OF), and also increase of cdk1 and cdk2 but not statistically significant. These results are consistent with previous finding that OF treatment increase the cell viability of normal cells 30 . Pretreatment with OF (Figure 2B) diminished the expression of cell cycle/proliferation markers that were induced by DIO (Figure 2B), especially the expression of cdk1 and cdk2 .…”

“…Those results echo our previous finding that OF binds to ASGR, increases P1-HNF4A through activating pSTAT3 on normal hepatocyte. 30 HNF4A plays crucial role in liver inflammatory networks, 54 suppresses liver cancer formation 55 and activation. HNF4A by small activating RNA could prevent NAFLD and improve metabolic profile.…”

“…OF (0.051 mg in 5 μL) was administrated by oral gavage thrice a week for 1 month starting at 4 months of age, by injected slowly into the intestinal tract of anesthetized (with 150 mg/L MS‐222) adult fish using flexible tubing as described previously 31 . After 1 month of OF oral feeding, we sacrificed the fish, extracted the RNA, and paraffin embedding for H&E stain was performed as described previously 30,31 . The quantitative real‐time PCR (qPCR) primers are listed in Table 1.…”

“…33 The same material has been used in different experiments including in vitro and in vivo models, and demonstrated that OF exhibits hepatocyte protection and anti-radiation induced fibrosis and secondary tumor. 30,31,34…”

“…28 In addition, the sialic acid loss in platelets exposing galactose activates pSTAT3, where STAT3 is signal transducer and activator of transcription 3, by binding to ASGR in hepatocytes. 29 Previously, we have demonstrated OF protects the liver through binding to ASGR and activates STAT3 in normal liver cells, 30 and prevents radiation induced firbosis and secondary tumor. 31 In this study, we investigated whether OF would be capable of reducing cancer incidence in different transgenic zebrafish HCC models including [HBx,src,p53 −/+ ] transgenic zebrafish under diet induced obesity (DIO) developed HCC at 5 months of age, 14 and CD36 transgenic zebrafish under high-fat diet induced HCC at 1 month.…”