Hepatopancreas Proteomic Analysis Reveals Key Proteins and Pathways in Regulatory of Ovary Maturation of Macrobrachium nipponense

SIMPLE SUMMARY: The crustacean hepatopancreas was reported to play important roles in ovarian maturation, providing not only energy but also essential fatty acids and cholesterol required for the synthesis of steroid hormones. In addition, it is also an important site of vitellogenin synthesis in crustaceans. The role of crustacean hepatopancreas in regulating ovarian maturation in crustaceans has attracted more attention. However, the molecular mechanisms about the regulation are little known in scientific research. Our data indicated the key proteins of carbohydrate metabolism, lipid metabolism, amino acid metabolism, and lysosome pathways played important roles in hepatopancreas, as the ovaries developed to maturation in Macrobrachium nipponense. The results provide new insight into regulatory mechanisms of hepatopancreas in crustacean reproduction. ABSTRACT: A TMT-based (Tandem Mass Tag) liquid chromatography-tandem mass spectrometry (LC-MS/MS) proteomics approach was employed to explore differentially expressed proteins (DEPs) and KEGG pathways in hepatopancreas of 5 ovary stages. In total, 17,999 peptides were detected, among which 3395 proteins were identified. Further analysis revealed 26, 24, 37, and 308 DEPs in HE-I versus HE-II, HE-II versus HE-Ⅲ, HE-Ⅲ versus HE-Ⅳ, and HE-Ⅳ versus HE-Ⅴ, respectively (HE-I, HE-II, HE-III, HE-IV, and HE-V means hepatopancreas sampled from ovary stage I to V.). Gene ontology (GO) analysis indicated that DEPs were significantly enriched in “catalytic activity”, “metabolic process”, and “cell” of 4 comparison groups in turn. Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment results showed that in hepatopancreas, as the ovaries developed to maturation, carbohydrate metabolism, lipid metabolism, amino acid metabolism, and lysosome played important roles in turn. The mRNA expression of 15 selected DEPs were consistent with proteome results by qPCR analysis. Further mRNA expression investigation results suggested 4 proteins (fatty acid-binding protein, NPC intracellular cholesterol transporter 1, Serine hydroxymethyltransferase, and Crustapin) were involved in ovary maturation. These results enhance the understanding of the regulatory role of hepatopancreas in M. nipponense ovary maturation and provide new insights for understanding the crustacean regulation mechanisms.