An insulin-like peptide serves as a regulator of glucose metabolism in the immune response of Chinese mitten crab Eriocheir sinensis. (July 2020)

• Record Type: Journal Article
• Authors: Wang, Lin; Chen, Hao; Wang, Lingling; Song, Linsheng
• Is Part Of: Developmental and comparative immunology. Volume 108(2020)
• Publication Date: 2020-07
• Subjects: Aeromonas hydrophila infection -- Chinese mitten crab -- Glucose metabolism -- Insulin-like peptide -- Immune response; Immunology -- Periodicals; Developmental immunology -- Periodicals; 616.079
• DOI: 10.1016/j.dci.2020.103686
• Languages: English
• ISSNs: 0145-305X

Abstract

Abstract: A robust immune response against invading pathogens greatly depends on the balance of metabolism, which could be vigorously modulated by insulin/IGF signaling (IIS) pathway in vertebrates. However, knowledge on the IIS pathway, especially the function of insulin-like peptides (ILPs) in invertebrates remained largely unknown. In the present study, a novel ILP was identified from Eriocheir sinensisis (designated Es ILP). The coding sequence of Es ILP was of 216 bp, which encoded a polypeptide of 71 amino acids containing an IlGF-like domain with four conserved cysteine residues. The mRNA transcripts of EsILP were found to be expressed dominantly in eyestalks and hepatopancreas, and Es ILP protein was found to be distributed in the anterior median area of thoracic ganglion mass and the edges of hepatic tubules correspondingly. After Aeromonas hydrophila stimulation, EsILP transcripts were significantly increased at 3, 12 and 24 h post-stimulation in eyestalks and 6 and 48 h in hemocytes, respectively. In contrast, the expression level of EsILP decreased significantly in hepatopancreas from 6 h to 12 h after the stimulation. The glucose level in the hemolymph of crabs was significantly decreased from 6 to 12 h after the injection of recombinant Es ILP. These results collectively demonstrated that the ancient ILP protein in E. sinensisis could negatively regulate glucose metabolism and participate in the immune response of the crabs against pathogen infection, which provided clues for the further investigation about the evolution and function of the IIS pathway in invertebrates. Highlights: Es ILP was a homologue of invertebrate insulin-like peptide in Eriocheir sinensis. EsILP transcripts and protein main distributed in metabolic and endocrine tissues. EsILP mRNA transcripts were vigorously modulated during bacterial infection. Es ILP protein could negatively regulate glucose level in E. sinensisis.