Molecular characterization of AMP-activated protein kinase (AMPK) α1/α2 from Cyprinus carpio and its roles in glucolipid metabolism and immune response

Int J Biol Macromol. 2025 Apr:303:140736. doi: 10.1016/j.ijbiomac.2025.140736. Epub 2025 Feb 5.

Abstract

AMPKα1 and AMPKα2, key kinases in regulating energy homeostasis, have not been previously cloned or characterized in common carp (Cyprinus carpio). This study identified the open reading frame (ORF) sequences of ampkα1 (1722 bp, encoding 573 amino acids) and ampkα2 (1659 bp, encoding 552 amino acids) through homologous cloning. Sequence alignment and phylogenetic analysis showed a high similarity of both genes with fish homologs. Expression analysis revealed that ampkα1 and ampkα2 are widely expressed across tissues in carp, with ampkα1 highly expressed in the gonads and ampkα2 in the heart. Fasting significantly reduced ampkα1 expression in the heart, adipose tissue, and foregut but increased it in the hindgut and white muscle. Similarly, ampkα2 expression decreased in the hypothalamus and muscle during fasting, with an increase in the midgut. Glucose tolerance tests showed dynamic regulation of ampkα1 and ampkα2, with initial downregulation followed by upregulation in the hepatopancreas, red muscle, and brain. High-glucose and high-fat diets significantly increased ampkα1 and ampkα2 expression in multiple tissues. Insulin and glucagon treatment induced time-dependent changes in both genes in hepatocytes, while Aeromonas hydrophila infection, LPS, and Poly (I:C) stimulation upregulated ampkα1 and ampkα2 in immune-related tissues. Knockdown of ampkα2, but not ampkα1, reduced glut1b mRNA levels, while both knockdowns of ampkα1 and ampkα2 promoted the expression of gsk3β, pygm, acc, fas, srebp, cs, and pro-inflammatory cytokines, suggesting their involvement in metabolic and immune regulation in carp.

Keywords: AMPK; Cyprinus carpio; Glucolipid metabolism; Immune response; Molecular characterization.

MeSH terms

  • AMP-Activated Protein Kinases* / chemistry
  • AMP-Activated Protein Kinases* / genetics
  • AMP-Activated Protein Kinases* / metabolism
  • Aeromonas hydrophila
  • Amino Acid Sequence
  • Animals
  • Carps* / genetics
  • Carps* / immunology
  • Carps* / metabolism
  • Carps* / microbiology
  • Cloning, Molecular
  • Glucose* / metabolism
  • Lipid Metabolism*
  • Phylogeny

Substances

  • AMP-Activated Protein Kinases
  • Glucose