Emerging technologies for amino acid nutrition research in the post-genome era.

Amino acids (AA) are not only the building blocks of proteins but are also key regulators of metabolic pathways in cells. However, the mechanisms responsible for the effects of AA are largely unknown. With the completion of human and other mammalian genome projects, revolutionary technologies in life sciences characterized by high throughput, high efficiency, and rapid computation are now available for AA nutrition research. These advanced tools include genetics (the genomic variety), epigenetics (stable and heritable changes in gene expression or cellular phenotype that occurs without changes in DNA sequence), transcriptomics (alternative mRNA splicing, microRNAs, and gene transcription), proteomics (protein expression and interactions), metabolomics (metabolite profiles in cells and tissues), and bioinformatics (analysis of metabolic pathways using systems biology approach). These robust, powerful methods can be employed for the analysis of DNA, RNA, protein, and low-molecular-weight metabolites, whose expression and concentration are affected by the interaction between genes and dietary AA. With the omics and other advanced methodologies, we expect that the molecular actions of AA on target tissues can be defined and that optimal dietary recommendations for these nutrients can be devised for individual humans (personalized nutrition) and animals (targeted feeding) in response to changes in physiological and pathological conditions.