Identification and Quantification of Proteins from Preparative Partition Chromatography and Peptides from Organic Extraction of Fetal Versus Adult Bovine Serum using Nano-Spray-LC-ESI-MS/MS

Blood proteins communicate with many different cells, tissue and organs; perform key functions in the immune system and may be of particular biological complexity. One of the most widely used blood products in the laboratory is fetal bovine serum for cell culture. There are ethical and practical concerns regarding the use of fetal serum from animals and alternative serum-free replacements have been attempted using platelet lysates. Previous biochemical experiments have shown that FBS apparently contained factors such as alpha-feto protein (AFP) and insulin-like growth factors that may support the indefinite cell growth and division of certain cell lines. It is presumed that a set of as yet undefined growth factors transform cells growth resulting in rapid proliferation. Cultured Raw cells 264.7 in adult bovine serum multiplied slowly and differentiated into elongated cells with a dendritic shape, which died after the first few generations. On the contrary, in fetal bovine serum, cultured cells multiplied rapidly and formed many smaller cells with a rounded shape through many cell passages. Three independent batches of fetal bovine serum were tested on Raw cells 264.7 macrophages to confirm that they supported cell growth in culture compared to three independent batches of adult bovine serum. The intact proteins of each serum sample were separated by partition chromatography into 16 fractions with an increasing step gradient of salts over quaternary amine resin (proteomics). The endogenous peptides were precipitated with 90% of acetonitrile and extracted into 10 fractions with a decreasing step gradient of acetonitrile in water (peptidomics). Trypsin digested intact proteins and endogenous peptides were then analyzed on a fresh C18 nano-HPLC column with random and independent sampling by LC-ESI-MS/MS. The fractionated mass spectra were identified with SEQUEST and X!TANDEM algorithms. Redundant use of MS/MS spectra were flirted out with the SQL Server system and the R statistical analysis system was used to perform Chi Square (X2) analysis of frequency counts and ANOVA of the log10 precursor intensity results. Alpha-feto protein, fetal albumin, insulin, insulin like growth factors, platelet derived growth factors and proteins associated with HRAS/AKT growth pathway at the level of ligand, receptors, receptor associated enzyme and nucleic acid binding proteins including transcription factors were observed to be specifically enriched in fetal serum.

Identification and Quantification of Proteins from Preparative Partition Chromatography and Peptides from Organic Extraction of Fetal Versus Adult Bovine Serum using Nano-Spray-LC-ESI-MS/MS

Blood proteins communicate with many different cells, tissue and organs; perform key functions in the immune system and may be of particular biological complexity. One of the most widely used blood products in the laboratory is fetal bovine serum for cell culture. There are ethical and practical concerns regarding the use of fetal serum from animals and alternative serum-free replacements have been attempted using platelet lysates. Previous biochemical experiments have shown that FBS apparently contained factors such as alpha-feto protein (AFP) and insulin-like growth factors that may support the indefinite cell growth and division of certain cell lines. It is presumed that a set of as yet undefined growth factors transform cells growth resulting in rapid proliferation. Cultured Raw cells 264.7 in adult bovine serum multiplied slowly and differentiated into elongated cells with a dendritic shape, which died after the first few generations. On the contrary, in fetal bovine serum, cultured cells multiplied rapidly and formed many smaller cells with a rounded shape through many cell passages. Three independent batches of fetal bovine serum were tested on Raw cells 264.7 macrophages to confirm that they supported cell growth in culture compared to three independent batches of adult bovine serum. The intact proteins of each serum sample were separated by partition chromatography into 16 fractions with an increasing step gradient of salts over quaternary amine resin (proteomics). The endogenous peptides were precipitated with 90% of acetonitrile and extracted into 10 fractions with a decreasing step gradient of acetonitrile in water (peptidomics). Trypsin digested intact proteins and endogenous peptides were then analyzed on a fresh C18 nano-HPLC column with random and independent sampling by LC-ESI-MS/MS. The fractionated mass spectra were identified with SEQUEST and X!TANDEM algorithms. Redundant use of MS/MS spectra were flirted out with the SQL Server system and the R statistical analysis system was used to perform Chi Square (X2) analysis of frequency counts and ANOVA of the log10 precursor intensity results. Alpha-feto protein, fetal albumin, insulin, insulin like growth factors, platelet derived growth factors and proteins associated with HRAS/AKT growth pathway at the level of ligand, receptors, receptor associated enzyme and nucleic acid binding proteins including transcription factors were observed to be specifically enriched in fetal serum.

Human Cells Grown With or Without Substitutes for Fetal Bovine Serum

Safety concerns over cell-derived pharmaceutical products being manufactured in supplements of fetal bovine serum (FBS) have ignited pleas to replace FBS. Herein, four newly marketed alternatives to FBS were compared: a xeno-free product called Cell-Ess®, a human platelet lysate marketed as GroPro®, and two mixtures of adult bovine serum varying in their proportions of neonatal growth factors, called Liporo® and FetalGro®. An endothelial cell line (C2BBe1) and a neuronal cell line (SHSY5Y) near confluency in media with 10% FBS were selectively scraped and taken through a 25-day step-wise algorithm to replace FBS, and another human endothelial cell line (HRA-19) was studied to replicate C2BBe1. Cells were stained, counted, and compared for viability, migration, and spheroids. The C2BBe1 and HRA-19 cell lines failed to proliferate in 10% Cell-Ess® but grew in 10% GroPro® or 10% FetalGro® reasonably well compared to reference 10% FBS. With SH-SY5Y, only FetalGro® approached FBS's efficacy. These were all inferior to 11 different branded lots of FBS (positive controls), but five days into switching just amongst the FBS brands, 4 of 11 supported less proliferation than reference FBS in endothelial HRA-19 ( p < 0.004). Moreover, neurospheres were enriched in two branded lots of FBS and FetalGro® (each p < 0.004), neurospheres being an unwanted phenotype for any neuronal cell application. Because platelet-derived GroPro® stood out amongst the non-FBS growth supplements to allow proliferation without inducing spheroids, it seems the best (mindful that the cells still grew slower in it compared to FBS). While no perfect replacement was found amongst the alternatives to FBS, the algorithm for switching should be useful in future testing of new alternatives to FBS as the need arises to switch from FBS and expand pharmaceutical products with safety for human use.

Environmental cystine drives glutamine anaplerosis and sensitizes cancer cells to glutaminase inhibition

Many mammalian cancer cell lines depend on glutamine as a major tri-carboxylic acid (TCA) cycle anaplerotic substrate to support proliferation. However, some cell lines that depend on glutamine anaplerosis in culture rely less on glutamine catabolism to proliferate in vivo. We sought to understand the environmental differences that cause differential dependence on glutamine for anaplerosis. We find that cells cultured in adult bovine serum, which better reflects nutrients available to cells in vivo, exhibit decreased glutamine catabolism and reduced reliance on glutamine anaplerosis compared to cells cultured in standard tissue culture conditions. We find that levels of a single nutrient, cystine, accounts for the differential dependence on glutamine in these different environmental contexts. Further, we show that cystine levels dictate glutamine dependence via the cystine/glutamate antiporter xCT/SLC7A11. Thus, xCT/SLC7A11 expression, in conjunction with environmental cystine, is necessary and sufficient to increase glutamine catabolism, defining important determinants of glutamine anaplerosis and glutaminase dependence in cancer.

Environmental cystine drives glutamine anaplerosis and sensitizes cells to glutaminase inhibition

Many cancer cell lines depend on extracellular glutamine as a major tri-carboxylic acid (TCA) cycle anaplerotic substrate to support proliferationin vitro. However, recent studies have suggested that some cells that depend on glutamine anaplerosis in culture rely much less on glutamine catabolism to proliferatein vivo, with environmental differences between tumors and cell culture influencing the extent of glutamine catabolism. Here we sought to better understand the environmental differences that cause differential dependence on glutamine for TCA cycle anaplerosis. We find that cells cultured in adult bovine serum, a condition that more closely reflects the nutrients available to cellsin vivo, leads to decreased glutamine catabolism and reliance on glutamine anaplerosis compared to standard tissue culture conditions. By analyzing the nutrient differences between bovine serum and media, we find that levels of a single nutrient, cystine, can account for the differential dependence on glutamine in these different environmental contexts. Further, we show that cystine levels dictate glutamine dependence via the cystine/glutamate antiporter xCT/SLC7A11, and that environmental cystine levels in conjunction withxCT/SLC7A11expression is necessary and sufficient to drive increased glutamine anaplerosis, defining important determinants of glutamine anaplerosis and glutaminase dependence in cancer cells.

Structural Features and Transcriptional Activity of Chicken PPARs (α,β, andγ)

While an understanding of lipid metabolism in chickens is critical for a further improvement of food production, there are few studies concerning differences in lipid metabolism mechanisms between chickens and other species at a molecular level. Chickens have three PPAR gene subtypes (α,β, andγ) that function differently from those present in humans and mice. The chicken PPAR-gamma (cPPARγ) gene is shorter than that in humans and lacks aγ2 isoform. Moreover, in serum-free media, cPPARγshows high transcriptional activity without exogenous ligands. Luciferase reporter assays were used to examine the effect of sera on cPPAR transcriptional activities and showed that adult bovine serum and chicken serum highly activate cPPARαandβfunctions. Moreover, we found that bezafibrate induces the transactivation function of cPPARβ, but not human PPARδ(human PPARβortholog). This ligand selectivity relies on one amino acid residue (chicken: Val419, human: Met444). These results show the possibilities for unique functions of cPPARs on chicken-specific lipid glucose metabolism. As such, a better understanding of the molecular mechanisms of lipid metabolism in chickens could result in higher productivity for the poultry industry.

Conglutinin is not specific to cattle

&nbsp; &nbsp;Conglutinin is a high-molecular-weight mammalian lectin which binds in a calcium-dependent manner to cell-surface-bound complement fragment iC3b, yeast cell-wall extract and terminal non-reducing N-acetyl-D-glucosamine, mannose and fucose residues. This protein, originally detected in bovine serum, belongs to the family of collectins, which are effector molecules in innate immunity. Conglutinin appears to play an important role in defence mechanisms, showing antiviral and antibacterial activity. We have characterized the electrophoresis profile of bovine serum conglutinin and used Western blotting to compare profiles of this lectin derived from the sera of different breeds of cattle. The profile of non-reduced conglutinin is characterised by many bands with molecular masses ranging from 34 to 630 kDa. Reduced lectin takes the form of three main bands with molecular masses of 41, 47 and 96 kDa. We show that conglutinin is present not only in adult bovine serum, but also in foetal bovine serum, colostrum and milk. The sera of sheep, goats, gnu antelopes and deer, as well as some non-ruminant species such as llamas, horses, boars, pigs and humans, contain proteins which have similar antigenicity to that of bovine conglutinin. These reacted with monoclonal and polyclonal antibodies specific for bovine conglutinin under reducing and non-reducing conditions in Western blotting. The protein profiles of bison and swine lectin were observed to be particularly similar to bovine conglutinin.