Both datasets contain cycling progenitors, and heterogeneity between cell cycle stages for these cells has been previously been shown to confound developmental analyses. Therefore, independently for both datasets, we first assigned a cell cycle score to each cell using the PCA method57 (link) on a previously annotated list of cell cycle genes58 (link). We then used the ScaleData function in Seurat (using the cell cycle score as latent variable in a linear regression framework) to mitigate this source of variation in the dataset, prior to CCA.
Stem Cells
They can self-renew and divide to produce more stem cells or differentiate into specialized cells.
Stem cell research is vital for understanding human development, tissue regeneration, and the potential treatment of diseases.
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We applied BEAM analysis to identify genes significantly bifurcating between Ery/Meg and GMP branch on the Olsson wildtype dataset. We then calculate the instant log ratios (ILRs) of gene expression between Ery/Meg and GMP branch and find genes have mean ILR larger than 0.5. The ILRs are defined as:
So
is calculated as the log ratio of fitted value at interpolated pseudotime point
for the Ery/Meg lineage and that for the GMP lineage. Those genes are used to calculate the lineage score (simply calculated as average expression of those genes in each cell, same as stemness score below) for both of the Olsson and the Paul dataset which is used to color the cells in a tree plot transformed from the high dimensional principal graph (see
In addition, pseudotime dependent genes for the Ery/Meg and GMP branch are identified in the Olsson wildtype dataset. All genes that always have lower expression from both lineages than the average in the progenitor cells are selected. Those genes are used to calculate the stemness score for both of the Olsson and the Paul dataset which is used to color the cells in the tree plot.
In Monocle 2, we extended the capability to test for branch-dependent gene expression by formulating the problem as a contrast between two negative binomial GLMs.
The null model
for the test assumes the gene being tested is not a branch specific gene, whereas the alternative model:
assumes that the gene is a branch specific gene where : represents an interaction term between branch and transformed pseudotime, NB means negative binomial distribution. Each model includes a natural spline (here with three degrees of freedom) describing smooth changes in mean expression as a function of pseudotime. The null model fits only a single curve, whereas the alternative will fit a distinct curve for each branch. Our current implementation of Monocle 2 relies on VGAM’s “smart” spline fitting functionality, hence the use of the sm.ns() function instead of the more widely used ns() function from the splines package in R50 (link). Likelihood ratio testing was performed with the VGAM lrtest() function, similar to Monocle’s other differential expression tests50 (link). A significant branch-dependent genes means that the gene has distinct expression dynamics along each branch, with smoothed curves that have different shapes.
To fit the full model, each cell must be assigned to the appropriate branch, which is coded through the factor “Branch” in the above model formula. Monocle’s function for testing branch dependence accepts an argument specifying which branches are to be compared. These arguments are specified using the ‘State’ attribute assigned by Monocle during trajectory reconstructions. For example, in our analysis of the Truetlein et al data 25 (link), Monocle reconstructed a trajectory with two branches (LAT1, LAT2 for AT1 and AT2 lineages, respectively), and three states (SBP, SAT1, SAT2 for progenitor, AT1, or AT2 cells). The user specifies that he or she wants to compare LAT1 and LAT2 by providing SAT1 and SAT2 as arguments to the function. Monocle then assigns all the cells with state SAT1 to branch LAT1 and similarly for the AT2 cells. However, the cells with SBP must be members of both branches, because they are on the path from each branch back to the root of the tree. In order to ensure the independence of data points required for the LRT as well as the robustness and stability of our algorithm, we implemented a strategy to partition the progenitor cells into two groups, with each branch receiving a group. The groups are computed by simply ranking the progenitor cells by pseudotime and assigning the odd-numbered cells to one group and the even numbered cells to the other. We assign the first progenitor to both branches to ensure they start at the same time which is required for downstream spline fitting and clustering. The branch plots in
Most recents protocols related to «Stem Cells»
Example 7
The MTT Cell Proliferation assay determines cell survival following apple stem cell extract treatment. The purpose was to evaluate the potential anti-tumor activity of apple stem cell extracts as well as to evaluate the dose-dependent cell cytotoxicity.
Principle: Treated cells are exposed to 3-(4,5-dimethythiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT). MTT enters living cells and passes into the mitochondria where it is reduced by mitochondrial succinate dehydrogenase to an insoluble, colored (dark purple) formazan product. The cells are then solubilized with DMSO and the released, solubilized formazan is measured spectrophotometrically. The MTT assay measures cell viability based on the generation of reducing equivalents. Reduction of MTT only occurs in metabolically active cells, so the level of activity is a measure of the viability of the cells. The percentage cell viability is calculated against untreated cells.
Method: A549 and NCI-H520 lung cancer cell lines and L132 lung epithelial cell line were used to determine the plant stem cell treatment tumor-specific cytotoxicity. The cell lines were maintained in Minimal Essential Media supplemented with 10% FBS, penicillin (100 U/ml) and streptomycin (100 μg/ml) in a 5% CO2 at 37 Celsius. Cells were seeded at 5×103 cells/well in 96-well plates and incubated for 48 hours. Triplicates of eight concentrations of the apple stem cell extract were added to the media and cells were incubated for 24 hours. This was followed by removal of media and subsequent washing with the phosphate saline solution. Cell proliferation was measured using the MTT Cell Proliferation Kit I (Boehringer Mannheim, Indianapolis, IN) New medium containing 50 μl of MTT solution (5 mg/ml) was added to each well and cultures were incubated a further 4 hours. Following this incubation, DMSO was added and the cell viability was determined by the absorbance at 570 nm by a microplate reader.
In order to determine the effectiveness of apple stem cell extracts as an anti-tumor biological agent, an MTT assay was carried out and IC50 values were calculated. IC50 is the half maximal inhibitory function concentration of a drug or compound required to inhibit a biological process. The measured process is cell death.
Results: ASC-Treated Human Lung Adenocarcinoma Cell Line A549.
Results: ASC-Treated Human Squamous Carcinoma Cell Line NCI-H520.
Results: ASC-treated Lung Epithelial Cell Line L132.
Summary Results: Cytotoxicity of Apple Stem Cell Extracts.
Apple stem cell extracts killed lung cancer cells lines A549 and NCI-H520 at relatively low doses: IC50s were 12.58 and 10.21 μg/ml respectively as compared to 127.46 μg/ml for the lung epithelial cell line L132. Near complete anti-tumor activity was seen at a dose of 250 μg/ml in both the lung cancer cell lines. This same dose spared more than one half of the L132 cells. See Tables 7-10. The data revealed that apple stem cell extract is cytotoxic to lung cancer cells while sparing lung epithelial cells.
Example 9
The experiment of Example 7 was repeated substituting other plant materials for ASC. Plant stem cell materials included Dandelion Root Extract (DRE), Aloe Vera Juice (AVJ), Apple Fiber Powder (AFP), Ginkgo Leaf Extract (GLE), Lingonberry Stem Cells (LSC), Orchid Stem Cells (OSC) as described in Examples 1 and 2. The concentrations of plant materials used were nominally 250, 100, 50, 25, 6.25, 3.125, 1.562, and 0.781 μg/mL. These materials were tested only for cells the human lung epithelial cell line L132 (as a proxy for normal epithelial cells) and for cells of the human lung adenocarcinoma cell line A549 (as a proxy for lung cancer cells).
A549 cells lung cancer cell line cytotoxicity results for each of the treatment materials.
DRE-Treated Lung Cancer Cell Line A549 Cells.
AVJ-Treated Lung Cancer Cell line A549 Cells.
AFP-Treated Lung Cancer Cell line A549 Cells.
GLE-treated Lung Cancer Cell line A549 Cells.
LSC-treated lung cancer cell lines A549 cells.
OSC-treated Lung Cancer Cell line A549 Cells.
L132 cells (“normal” lung epithelial cell line) cytotoxicity results for each of the treatment materials.
DRE-Treated Lung Epithelial Cell Line L132 cells.
AVJ-Treated Lung Epithelial Cell Line L132 cells.
AFP-Treated Lung Epithelial Cell Line L132 cells.
GLE-Treated Lung Epithelial Cell Line L132 cells.
LSC-Treated Lung Epithelial Cell Line L132 cells.
OSC-Treated Lung Epithelial Cell Line L132 cells.
Calculated values.
Example 7
Impact of IL-2 signalling on Teff responses is characterised in a T cell activation assay, in which intracellular granzyme B (GrB) upregulation and proliferation are examined. Previously frozen primary human Pan T cells (Stemcell Technologies) are labelled with eFluor450 cell proliferation dye (Invitrogen) according to manufacturer's recommendation, and added to 96-U-bottom well plates at 1×105 cells/well in RPMI 1640 (Life Technologies) containing 10% FBS (Sigma), 2 mM L-Glutamine (Life Technologies) and 10,000 U/ml Pen-Strep (Sigma). The cells are then treated with 10 μg/ml anti-CD25 antibodies or control antibodies followed by Human T-Activator CD3/CD28 (20:1 cell to bead ratio; Gibco) and incubated for 72 hrs in a 37° C., 5% CO2 humidified incubator. To assess T cell activation, cells are stained with the eBioscience Fixable Viability Dye efluor780 (Invitrogen), followed by fluorochrome labelled antibodies for surface T cell markers (CD3-PerCP-Cy5.5 clone UCHT1 Biolegend, CD4-BV510 clone SK3 BD Bioscience, CD8-Alexa Fluor 700 clone RPA-T8 Invitrogen, CD45RA-PE-Cy7 clone HI100 Invitrogen, CD25-BUV737 clone 2A3 BD Bioscience) and then fixed and permeabilized with the eBioscience™ Foxp3/Transcription Factor Staining Buffer Set (Invitrogen) before staining for intracellular GrB and intranuclear FoxP3 (Granzyme B-PE clone GB11 BD Bioscience, FoxP3-APC clone 236A/E7). Samples are acquired on the Fortessa LSR X20 Flow Cytometer (BD Bioscience) and analysed using the BD FACSDIVA software. Doublets are excluded using FCS-H versus FCS-A, and lymphocytes defined using SSC-A versus FCS-A parameters. CD4+ and CD8+ T cell subsets gated from the live CD3+ lymphocytes are assessed using a GrB-PE-A versus proliferation eFluor450-A plot. Results are presented as percentage of proliferating GrB positive cells from the whole CD4+ T cell population. Graphs and statistical analysis is performed using GraphPad Prism v7. (results not shown)
Example 8
Cell adhesion was also evaluated by means of in vitro scratch wound-healing assay. HDPSCs cells were analyzed by difference in staining with phalloidin (cell nucleus) and DAPI to visualize actin cytoskeleton.
Cell adhesion results showed excellent interaction and adhesion between neighboring cells in the presence of bioceramic composition. The Bioceramic composition sealer (CB5) and Bioceramic composition repair (CB6), showed a gradual increase in growth over time, an extended morphology and a high content of F-Actin (cell microfilamen), reaching confluence after 72 hours of culture.
The analysis of cell proliferation (via cell viability study), apoptosis, cell adhesion and morphology (via cell adhesion study) and migration (via cell migration study) showed very positive results, indicating that the proposed bioceramic composition induces the odonto/osteogenic mineralization and differentiation process in the presence of tooth-specific human stem cells (hDPSCs pulp). While a market resin sealer was also used in the comparative studies, however, all results were not satisfactory for this product.
Example 3
Verification of CD117 as a Marker for Ventral Midbrain Dopaminergic Progenitor Cells Derived from Different Pluripotent Stem Cell Sources
To verify that the correlation of CD117 with the highly important intracellular marker FoxA2, thus highlighting the ventral midbrain dopaminergic progenitor cells, is independent from the sources auf pluripotent stem cells. We could show this correlation for one iPS line (F5) and one ES line (1(15).
Example 16
Demonstrating CKA of CD34+ Stem Cell Derived Neutrophils (SCDNs)
Results were obtained via the xCELLigence assay with further populations of CD34+ Stem Cell Derived Neutrophils (
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More about "Stem Cells"
These versatile cells can self-renew, dividing and replenishing their own population, as well as differentiate into specific cell lineages, such as neurons, cardiomyocytes, or hepatocytes.
Stem cell research is a vital field of study that provides crucial insights into human development, tissue regeneration, and potential treatments for a wide range of diseases.
PubCompare.ai is a cutting-edge platform that enhances the reproducibility and accuracy of stem cell research by empowering researchers to quickly locate the best protocols from literature, preprints, and patents.
Using intelligent comparisons, PubCompare.ai helps identify the optimal methods and products, streamlining the stem cell research process.
Researchers can leverage PubCompare.ai's advanced technology to access a wealth of information related to stem cell culture and differentiation.
This includes protocols and techniques for using essential materials like fetal bovine serum (FBS), penicillin/streptomycin, Lymphoprep (a density gradient medium for isolating mononuclear cells), Matrigel (an extracellular matrix substrate), MTeSR1 medium (a defined, feeder-free medium for human embryonic stem cell culture), the ALDEFLUOR kit (for identifying and isolating stem and progenitor cells), L-glutamine (a crucial amino acid supplement), Accutase (an enzyme solution for dissociating cells), GlutaMAX (a stable L-glutamine alternative), and DMEM/F12 (a common culture medium for stem cells).
By leveraging PubCompare.ai's innovative technology, researchers can streamline their stem cell studies, enhance reproducibility, and accelerate the pace of discoveries in this vital field of science.