Transcriptome Analysis of Deoxynivalenol (DON)-Induced Hepatic and Intestinal Toxicity in Zebrafish: Insights into Gene Expression and Potential Detoxification Pathways.

The effects of deoxynivalenol (DON, 50 µg/mL) on the zebrafish liver and intestine were studied. Differentially expressed genes (DEGs) from mRNA and lncRNA were analyzed by RNA seq. Gene Ontology (GO) and signaling pathways were studied where the top 30 DEGs of each type of RNA were involved. The results showed there were 2325 up-regulated and 934 down-regulated DEGs of lncRNA in the intestinal tract, and 95 up-regulated genes and 211 down-regulated genes in the liver, respectively. GO functional annotation analysis showed that lncRNA was enriched in the biological processes, involving the RNA splicing, CSF1-CSF1R complexes, and MAP kinase activity. DEGs of lncRNA located in the KEGG signal pathways include the C-type lectin receptor signaling and the NOD-like receptor signaling pathways. Metabolism involves the biosynthesis of indole alkaloids, cancer pathways for human disease, MAPK and Rap1signaling pathways for environmental information processing, necroptosis and focal adhesion for cell processes. The mRNA gene expression analysis showed there were 1939 up-regulated, 1172 down-regulated genes and 866 up-regulated, 1211 down-regulated genes in the intestine and liver of zebrafish, respectively. This study provides transcriptome analysis and toxicological investigation of DON in the zebrafish liver and intestine, offering insights into gene expression patterns and potential detoxification pathways.

The sequence determinant causing different folding behaviors of insulin and insulin-like growth factor-1.

Although insulin and insulin-like growth factor-1 (IGF-1) belong to the insulin superfamily and share highly homologous sequences, similar tertiary structure, and a common ancestor molecule, amphioxus insulin-like peptide, they have different folding behaviors: IGF-1 folds into two thermodynamically stable tertiary structures (native and swap forms), while insulin folds into one unique stable structure. To further understand which part of the sequence determines their different folding behavior, based on previous reports from the laboratory, two peptide models, [B9A][1-4]porcine insulin precursor (PIP) and [B10E][1-4]PIP, were constructed. The plasmids encoding the peptides were transformed into yeast cells for expression of the peptides; the results showed that the former peptide was expressed as single component, while the latter was expressed as a mixture of two components (isomer 1 and isomer 2). The expression results together with studies of circular dichoism, disulfide rearrangement, and refolding lead us to deduce that isomer 1 corresponds to the swap form and the isomer 2 corresponds to the native form. We further demonstrate that the sequence 1-4 plus B9 of IGF-1 B-domain can make PIP fold into two structures, while sequence 1-5 of insulin B-chain can make IGF-1 fold into one unique structure. In other words, it is the IGF-1 B-domain sequence that 1-4 allows IGF-1 folding into two thermodynamically stable tertiary structures; this sequence plus its residue B9E can change PIP folding behavior from folding into one unique structure to two thermodynamically stable structures, like that of IGF-1.