Integrated Metabolomic and Transcriptomic Analyses Reveal that Glutamine Promotes Chicken PGCLC Specification Potentially through α-Ketoglutarate.
Objective Primordial germ cell (PGC) is essential for germline transmission and genetic resource conservation in poultry. Although several genes and signaling pathways involved in PGC specification have been identified, the upstream regulatory mechanisms-particularly metabolic regulation and epigenetic modification-remain poorly understood. This study aimed to characterize the metabolic landscape underlying chicken PGC formation and identify key metabolic regulators involved in BMP4-induced primordial germ cell‑like cell (PGCLC) specification in vitro. Methods Untargeted metabolomics and transcriptomics were performed to compare metabolic profiles and gene expression patterns between chicken embryonic stem cell (ESC) and PGC. Differential metabolites and metabolism-related genes were identified through integrated multi-omics analysis. Functional experiments, including glutamine deprivation and metabolite supplementation, were conducted to verify the role of glutamine metabolism in PGCLC specification. Results A total of 194 differentially expressed metabolites (DEMs) were identified, mainly enriched in amino acid, nucleotide, energy metabolism, and antioxidant pathways. Compared with ESC, PGC contained higher levels of amino acids, peptides, and benzoic acid derivatives, whereas carbohydrates were more abundant in ESC. Transcriptomic analysis of 14,405 annotated genes revealed similar metabolic gene expression patterns in male and female samples. Integrated analysis indicated that amino acid metabolism, particularly glutamine metabolism, plays a key role in PGC formation. Glutamine deprivation significantly inhibited PGCLC specification, disrupted the balance between glycolysis and oxidative phosphorylation, and altered H3K4me2 epigenetic modification. Supplementation with the glutamine-derived tricarboxylic acid (TCA) cycle metabolite α-ketoglutarate (α-KG) markedly restored the reduced efficiency of PGCLC specification caused by glutamine depletion. Conclusion Glutamine promotes chicken PGCLC specification and is associated with alterations in cellular metabolism and increased H3K4me2 levels during differentiation. These findings suggest a potential association between glutamine metabolism, α-KG, and epigenetic regulation during germ cell development, providing new insights into the metabolic basis of PGC formation and a foundation for improving PGC culture and expansion in poultry.