Glutamine regulates expression of key transcription factor, signal transduction, metabolic gene, and protein expression in a clonal pancreatic beta-cell line.
We have investigated the effects of prolonged exposure (24 h) to the amino acid l-glutamine, on gene and protein expression using clonal BRIN-BD11 beta-cells. Expression profiling of BRIN-BD11 cells was performed using oligonucleotide microarray analysis. Culture for 24 h with 10 mM l-glutamine compared with 1 mM resulted in substantial changes in gene expression with 148 genes upregulated more than 1.8-fold, and 18 downregulated more than 1.8-fold, including many genes involved in cellular signaling, metabolism, gene regulation, and the insulin-secretory response. Subsequent functional experiments confirmed that l-glutamine increased the activity of the Ca(2+) regulated phosphatase calcineurin and the transcription factor Pdx1. Additionally, we demonstrated that beta-cell-derived l-glutamate was released into the extracellular medium at high rates. As calcineurin is a regulator of the glutamate N-methyl-d-aspartate (NMDA) receptor activity, we investigated the action of NMDA on nutrient-induced insulin secretion, and demonstrated suppressed insulin release. These observations indicate important long-term effects of l-glutamine in regulating beta-cell gene expression, signaling, and secretory function.
Corless
Mary
M
School of Biomolecular and Biomedical Sciences, Conway Institute, University College Dublin, Belfield, Dublin 4, Ireland.
Kiely
Aoife
A
McClenaghan
Neville H
NH
Flatt
Peter R
PR
Newsholme
Philip
P
D015153:Blotting, Western / Q000379:methods; D019703:Calcineurin / Q000235:genetics / Q000378:metabolism; D002999:Clone Cells; D003864:Depression, Chemical; D024202:Electrophoretic Mobility Shift Assay; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation / Q000187:drug effects*; D018698:Glutamic Acid / Q000378:metabolism; D005973:Glutamine / Q000378:metabolism / Q000494:pharmacology*; D018398:Homeodomain Proteins / Q000235:genetics / Q000378:metabolism; D006801:Humans; D007328:Insulin / Q000378:metabolism; D000078790:Insulin Secretion; D050417:Insulin-Secreting Cells / Q000187:drug effects / Q000378:metabolism*; D016202:N-Methylaspartate / Q000494:pharmacology; D020411:Oligonucleotide Array Sequence Analysis; D011506:Proteins / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction / Q000502:physiology*; D013997:Time Factors; D015534:Trans-Activators / Q000235:genetics / Q000378:metabolism; D014157:Transcription Factors / Q000378:metabolism*
D018398:Homeodomain Proteins; D007328:Insulin; D011506:Proteins; D015534:Trans-Activators; D014157:Transcription Factors; C084010:pancreatic and duodenal homeobox 1 protein; D005973:Glutamine; D018698:Glutamic Acid; D016202:N-Methylaspartate; D019703:Calcineurin