Dataset Information

Assessing the impact of minimizing arginine conversion in fully defined SILAC culture medium in human embryonic stem cells.

ABSTRACT: We present a fully defined culture system (adapted Essential8TM [E8TM ] medium in combination with vitronectin) for human embryonic stem cells that can be used for SILAC purposes. Although a complete incorporation of the labels was observed after 4 days in culture, over 90% of precursors showed at least 10% conversion. To reduce this arginine conversion, E8TM medium was modified by adding (1) l-proline, (2) l-ornithine, (3) N? -hydroxy-nor-l-arginine acetate, or by (4) lowering the arginine concentration. Reduction of arginine conversion was best obtained by adding 5 mM l-ornithine, followed by 3.5 mM l-proline and by lowering the arginine concentration in the medium to 99.5 ?M. No major changes in pluripotency and cell amount could be observed for the adapted E8TM media with ornithine and proline. However, our subsequent ion mobility assisted data-independent acquisition (high-definition MS) proteome analysis cautions for ongoing changes in the proteome when aiming at longer term suppression of arginine conversion.

SUBMITTER: Scheerlinck E

PROVIDER: S-EPMC5096064 | biostudies-literature | 2016 Oct

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Assessing the impact of minimizing arginine conversion in fully defined SILAC culture medium in human embryonic stem cells.

Scheerlinck Ellen E Van Steendam Katleen K Daled Simon S Govaert Elisabeth E Vossaert Liesbeth L Meert Paulien P Van Nieuwerburgh Filip F Van Soom Ann A Peelman Luc L De Sutter Petra P Heindryckx Björn B Dhaenens Maarten M Deforce Dieter D

Proteomics 20160912 20

We present a fully defined culture system (adapted Essential8TM [E8TM ] medium in combination with vitronectin) for human embryonic stem cells that can be used for SILAC purposes. Although a complete incorporation of the labels was observed after 4 days in culture, over 90% of precursors showed at least 10% conversion. To reduce this arginine conversion, E8TM medium was modified by adding (1) l-proline, (2) l-ornithine, (3) Nω -hydroxy-nor-l-arginine a ...[more]

PMID: 27392809

Similar Datasets

Project description:Human embryonic stem (hES) cells are pluripotent, capable of differentiating into any cell type of the body, and therefore have the ability to provide insights into mechanisms of human development and disease, as well as to provide a potentially unlimited supply of cells for cell-based therapy and diagnostics. Knowledge of the adhesion receptors that hES cells employ to engage extracellular matrix (ECM) proteins is of basic biological interest and can enhance the design of cell culture and implantation systems to enable these biomedical applications. Although hES cells express a variety of cell surface receptors, little is known about which integrins are involved during subculture and passage. Matrigel is broadly used as a cell adhesive matrix for hES cell culture. Here, we sought to identify which integrins hES cells exploit for adhesion to Matrigel-coated surfaces in defined medium conditions. Using RT-PCR, flow cytometry, and fluorescence immunochemistry, we found that numerous integrins were expressed by H1 hES cells; however, antibody blocking assays indicated that only alpha(v)beta(3), alpha(6), beta(1), and alpha(2)beta(1) played a significant role in the initial adhesion of the hES cells to Matrigel in defined medium conditions. We subsequently identified a cohort of synthetic peptides that, when adsorbed to the culture surface, promoted H1 hES cell attachment and proliferation, as well as maintained a pluripotent phenotype. Peptides designed to engage with alpha(v)beta(3), alpha(6), beta(1), and alpha(2)beta(1) integrins and syndecan-1 were tested both individually and in various combinations. A combination of two integrin-engaging peptides (AG-10, C-16) and one syndecan-engaging peptide (AG-73) was sufficient to promote hES cell adhesion, maintenance, and proliferation. We propose that a specific integrin "fingerprint" is necessary for maintenance of hES cell self-renewal, and synthetic culture systems must capture this engagement profile for hES cells to remain undifferentiated.-Meng, Y., Eshghi, S., Li, Y. J., Schmidt, R., Schaffer, D. V., Healy, K. E. Characterization of integrin engagement during defined human embryonic stem cell culture.

Project description:Metabolic labeling with stable isotopes is a prominent technique for comparative quantitative proteomics and stable isotope labeling with amino acids in cell culture (SILAC) is the most commonly used approach. SILAC is, however, traditionally limited to simple tissue culture regiments and only rarely employed in the context of complex culturing conditions as those required for human embryonic stem cells (hESCs). Classic hESC culture is based on the use of mouse embryonic fibroblasts (MEFs) as a feeder layer and as a result possible xenogeneic contamination, contribution of unlabeled amino acids by the feeders, inter-laboratory variability of MEF preparation and the overall complexity of the culture system are all of concern in conjunction with SILAC. We demonstrate a feeder-free SILAC culture system based on a customised version of a commonly used chemically defined hESC medium developed by Ludwig et al. (2006) and commercially available as mTeSR1 . This medium, together with adjustments to the culturing protocol, facilitates reproducible labeling which is easily scalable to the protein amounts required by proteomic work flows. It greatly enhances the usability of quantitative proteomics as a tool for the study of mechanisms underlying hESCs differentiation and self-renewal. Mass spectrometric data was analysed using the MaxQuant suite of algorithms [version 1.3.0.5]. The data was searched against the Homo sapiens UniProtKB protein sequence database (downloaded on 10/24/2012, 68,108 entries including canonical and isoform sequence data). Enzyme specificity was set to trypsin, allowing for cleavage N-terminal to proline and between aspartic acid and proline. Carbamidomethylcysteine was set as a fixed modification, and oxidized methionine and N-acetylation were set as variable modifications. Labeled Arg and Lys were used as peptide modifications for quantitation. MaxQuant’s requantitation option was not used where incorporation efficiency and arginine to proline conversion were analyzed. The maximum mass deviation allowed was set at 20 ppm for the initial search, and 6 ppm for the main search for monoisotopic precursor ions; the mass error tolerance was set at 20 ppm for MS/MS peaks. A maximum of two missed cleavages and three labeled amino acids (arginine and lysine) were allowed. The required false discovery rates were set to 1% at the peptide and protein level (the protein level filter was disabled for incorporation efficiency and arginine to proline conversion testing), and the minimum required peptide length was set to 6 amino acids. Statistical analysis and plotting were performed using the R Statistical Programming Environment. The analyses performed are documented in an R package provided in the proteomeXchange repository and based on a publicly available collection of tools (RCFPD, URL: http://sourceforge.net/projects/rcfpd/).

Project description:Previous studies have found that arginine biosynthesis in Staphylococcus aureus is repressed via carbon catabolite repression (CcpA), and proline is used as a precursor. Unexpectedly, however, robust growth of S. aureus is not observed in complete defined medium lacking both glucose and arginine (CDM-R). Mutants able to grow on agar-containing defined medium lacking arginine (CDM-R) were selected and found to contain mutations within ahrC, encoding the canonical arginine biosynthesis pathway repressor (AhrC), or single nucleotide polymorphisms (SNPs) upstream of the native arginine deiminase (ADI) operon arcA1B1D1C1. Reverse transcription-PCR (RT-PCR) studies found that mutations within ccpA or ahrC or SNPs identified upstream of arcA1B1D1C1 increased the transcription of both arcB1 and argGH, encoding ornithine carbamoyltransferase and argininosuccinate synthase/lyase, respectively, facilitating arginine biosynthesis. Furthermore, mutations within the AhrC homologue argR2 facilitated robust growth within CDM-R. Complementation with arcB1 or arcA1B1D1C1, but not argGH, rescued growth in CDM-R. Finally, supplementation of CDM-R with ornithine stimulated growth, as did mutations in genes (proC and rocA) that presumably increased the pyrroline-5-carboxylate and ornithine pools. Collectively, these data suggest that the transcriptional regulation of ornithine carbamoyltransferase and, in addition, the availability of intracellular ornithine pools regulate arginine biosynthesis in S. aureus in the absence of glucose. Surprisingly, ~50% of clinical S. aureus isolates were able to grow in CDM-R. These data suggest that S. aureus is selected to repress arginine biosynthesis in environments with or without glucose; however, mutants may be readily selected that facilitate arginine biosynthesis and growth in specific environments lacking arginine. IMPORTANCE Staphylococcus aureus can cause infection in virtually any niche of the human host, suggesting that it has significant metabolic versatility. Indeed, bioinformatic analysis suggests that it has the biosynthetic capability to synthesize all 20 amino acids. Paradoxically, however, it is conditionally auxotrophic for several amino acids, including arginine. Studies in our laboratory are designed to assess the biological function of amino acid auxotrophy in this significant pathogen. This study reveals that the metabolic block repressing arginine biosynthesis in media lacking glucose is the transcriptional repression of ornithine carbamoyltransferase encoded by arcB1 within the native arginine deiminase operon in addition to limited intracellular pools of ornithine. Surprisingly, approximately 50% of S. aureus clinical isolates can grow in media lacking arginine, suggesting that mutations are selected in S. aureus that allow growth in particular niches of the human host.

Dataset Information

Assessing the impact of minimizing arginine conversion in fully defined SILAC culture medium in human embryonic stem cells.

Publications

Assessing the impact of minimizing arginine conversion in fully defined SILAC culture medium in human embryonic stem cells.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets