Project description:The developmental origin of the c-kit expressing progenitor cell pool in the adult heart has remained elusive. Recently, it has been discovered that the injured heart is enriched with c-kit+ cells, which also express the hematopoietic marker CD45. In this study, we characterize the phenotype and transcriptome of the c-kit+/CD45+ cell population, originating from the left atrial appendage. These cells are defined as cardiac macrophage progenitors. We also demonstrate that the c-kit+/CD45+ progenitor cell population activates heart development, neural crest and pluripotency associated pathways in vitro, in conjunction with CD45 down-regulation, and acquire a c-kit+/lin- phenotype. This spontaneous reprogramming progresses further to a highly proliferative, partially myogenic phenotype. Our data suggests that c-kit+/lin- cells and cardiac macrophages have a common lineage origin possibly resolving some current conundrums in the field of cardiac regeneration. Two different stem cell types were grown by altering the tissue digestion protocol, from which one type was spontaneously transdifferentiating to other cell types. To investigate their transcriptional profiles we prepared RNA from two cell sorted replicates per cell type (A, B, C1, C2, C3).
Project description:The developmental origin of the c-kit expressing progenitor cell pool in the adult heart has remained elusive. Recently, it has been discovered that the injured heart is enriched with c-kit+ cells, which also express the hematopoietic marker CD45. In this study, we characterize the phenotype and transcriptome of the c-kit+/CD45+ cell population, originating from the left atrial appendage. These cells are defined as cardiac macrophage progenitors. We also demonstrate that the c-kit+/CD45+ progenitor cell population activates heart development, neural crest and pluripotency associated pathways in vitro, in conjunction with CD45 down-regulation, and acquire a c-kit+/lin- phenotype. This spontaneous reprogramming progresses further to a highly proliferative, partially myogenic phenotype. Our data suggests that c-kit+/lin- cells and cardiac macrophages have a common lineage origin possibly resolving some current conundrums in the field of cardiac regeneration. Two different stem cell types were grown by altering the tissue digestion protocol. To investigate their transcriptional profiles we prepared RNA from two cell sorted replicates per cell type and from two left ventricular biopsy samples as controls.
Project description:Aortic valve calcification is the most common form of valvular heart disease, but the mechanisms of calcific aortic valve disease (CAVD) are unknown. NOTCH1 mutations are associated with aortic valve malformations and adult-onset calcification in families with inherited disease. The Notch signaling pathway is critical for multiple cell differentiation processes, but its role in the development of CAVD is not well understood. The aim of this study was to investigate the molecular changes that occur with inhibition of Notch signaling in the aortic valve. Notch signaling pathway members are expressed in adult aortic valve cusps, and examination of diseased human aortic valves revealed decreased expression of NOTCH1 in areas of calcium deposition. To identify downstream mediators of Notch1, we examined gene expression changes that occur with chemical inhibition of Notch signaling in rat aortic valve interstitial cells (AVICs). We found significant downregulation of Sox9 along with several cartilage-specific genes that were direct targets of the transcription factor, Sox9. Loss of expression Sox9 has been published to be associated with aortic valve calcification. Utilizing an in vitro porcine aortic valve calcification model system, inhibition of Notch activity resulted in accelerated calcification while stimulation of Notch signaling attenuated the calcific process. Finally, the addition of Sox9 was able to prevent the calcification of porcine AVICs that occurs with Notch inhibition. In conclusion, loss of Notch signaling contributes to aortic valve calcification via a Sox9-dependent mechanism. 3 samples of aortic valve interstitial cells treated with DAPT were compared with 3 samples of aortic valve interstitial cells treated with DMSO
Project description:Purpose: Osteoblast cells mature from a mesenchymal stem cell pool to become cells capable of forming bone matrix and mineralizing this matrix. The goal of this study was to characterize temporal changes in the transcriptome across osteoblast maturation, starting with committed mesenchymal stem cell/ early pre-osteoblast stage through to mature osteoblasts capable of matrix mineralization. Methods: Enriched populations of pre-osteoblast like cells were obtained from neonatal calvaria from C57BL/6J mice expressing CFP under the control of the Col3.6 promoter. These cells were placed into culture for 4 days, removed from culture and subjected FACS sorting based on the presence/absence of CFP expression. Cells expressing CFP were returned to culture, subjected to an osteoblast differentiation cocktail and RNA was collected at 2, 4, 6, 8, 10, 12, 14, 16 and 18 days post differentiation. Methods II: mRNA profiles for each time point were generated by next generation RNA sequencing, using an Illumina HiSeq 2000. Three technical replicates per samples were sequenced. The alignments for abundance estimation of transcripts was conducted using Bowtie version 0.12.9, using the NCBIm37 reference genome. Expression level per gene was calculated using RSEM version 1.2.0 with the parameters of --fragment-length-mean 280 and --fragment-length-sd 50, and the expression level for each sample was normalized relative to the per sample upper quartile. Gene expression in calvarial osteoblasts from neonatal C57BL/6J-Col3.6 CFP mice at 9 time points post differentiation
Project description:Glioblastoma-derived neural stem (GNS) cells were reprogrammed to induced pluripotent stem (iPS) cells by transgenic expression of OCT4 and KLF4. Copy number status was determined for GNS and iPS cells to assess potential karyotype changes resulting from the reprogramming process.
Project description:Numerous lineage analysis studies have used FACS sorting as a separation technique prior to measuring mRNA expression patterns. To assess if FACS sorting causes non-specific changes in gene expression, we collected a heterogeneous population of mammary epithelial cells from three biological replicates. We then performed gene expression analysis on each replicate either prior to trypsin digestion, immediately following trypsin digestion, or following both the trypsin digestion and a mock FACS sort. In this dataset, we include gene expression data obtained from isolated murine mammary epithelial cells either prior to trypsin digestion, immediately following trypsin digestion, or following the trypsin digestion and a mock FACS sort. Nine total samples were analyzed (3 biological replicates of three experimental conditions). Using LIMMA packages gene-wise comparisons were made between untrypsinized and trypsinized replicates as well as between trypsinized and mock FACS sorted replicates using and P≤0.05 and a ≥1.5-fold difference between conditions.
Project description:The long term objective is to create an encyclopedia of the expression levels of all genes in multiple components of the developing kidney. The central thesis is straightforward. The combination of fluorescent activated cell sorting (FACS) plus microarray analysis offers a powerful, efficient and effective method for the creation of a global gene expression atlas of the developing kidney. Microarrays with essentially complete genome coverage can be used to quantitate expression levels of every gene in FACS isolated components of the developing kidney. The ensuing rapid read-out provides an expression atlas that is more sensitive, more economical and more complete than would be possible by in situ hybridizations alone. YFP & GFP transgenic lines have been used to isolate several cell types including the metanephric mesenchyme, Juxtaglomerular Complex cells or renal cortex from the kidneys of either E11.5 embryos or adult mice. The various cell types were isolated from the kidney using microdissection and single-cell isolation techniques. RNA was isolated from cells and the gene expression profiles were determined by microarrays.
Project description:The spinal cord is generated progressively as cells leave the caudal region of the elongating body axis such that the temporal steps of neural differentiation become spatially separated along the head to tail axis. At key stages, it is therefore possible to isolate near-adjacent cell populations from the same embryo in distinct differentiation states. Cells in the caudal lateral epiblast adjacent to the primitive streak (also known as the stem zone, SZ, in the chick) express both early neural and mesodermal genes. Other cells in the stem zone will gastrulate to form the paraxial mesoderm or remain in the epiblast cell sheet and become neural progenitors. These latter cells form a new region called the preneural tube (PNT), which is flanked by unsegmented presomitic mesoderm and represents an early neural progenitor state that can be induced by FGF signalling to revert back to a multi-potent SZ state. Rostral to this, the closed caudal neural tube (CNT) is flanked by somites and is an early site of co-expression of genes characteristic of neural progenitors, and of ventral patterning genes (Diez del Corral et al., 2003). The CNT contains the first few neurons and exposure to FGF cannot revert this tissue to a multi-potent SZ state (Diez del Corral et al., 2002). The transition from the PNT to the CNT thus involves commitment to a neural fate that this is regulated by a switch from FGF to retinoid signalling. More advanced neuroepithelium is then located in more rostral neural tube (RNT), in which neuronal differentiation is ongoing and dorsoventral pattern is refined. This experiment uses the Affymetrix GeneChip chicken genome microarray to compare the transcriptomes of microdissections of these spatially distinct cell populations from the elongating neural axis of HH stage 10 chick embryos. Dissections were carried out in L15 medium at 4°C and explants pooled in TRIzol reagent (Gibco) for RNA extraction. Notochord was removed by controlled trypsin digestion that aimed to keep the neural ventral midline. For the microarrays, at least five tissue samples for each region were pooled to make each of three biological replicates for each (n>15 for each region).
Project description:Purpose: Avian photoreceptors are a diverse class of neurons, comprised of four single cones, the two members of the double cone, and rods. Many distinctive features of photoreceptor subtypes, including spectral tuning, oil droplet size and pigmentation, synaptic targets and spatial patterning, have been well characterized, but the molecular mechanisms underlying these attributes have not been explored. Furthermore, the signaling events and transcriptional regulators driving the differentiation of these diverse photoreceptors are currently unknown. Methods: To identify genes specifically expressed in distinct chicken (Gallus gallus) photoreceptor subtypes, we developed fluorescent reporters that label photoreceptor subpopulations, isolated these subpopulations using fluorescence-activated cell sorting, subjected them to next-generation sequencing, and conducted differential expression analysis. Results: We identified hundreds of differentially expressed genes from photoreceptor subpopulations labeled with rhodopsin, red opsin, green opsin, and violet opsin reporters. These genes are involved in a variety of processes, including phototransduction, transcriptional regulation, cell adhesion, maintenance of intra- and extra-cellular structure, and metabolism. Of particular note are a variety of differentially expressed transcription factors, which may drive and maintain photoreceptor diversity, and cell adhesion molecules that may mediate spatial patterning of photoreceptors and act to establish retinal circuitry. Conclusions: These analyses provide a framework for future studies that will dissect the role of these various factors in the differentiation of avian photoreceptor subtypes. mRNA expression profiling of 5 pairs of photoreceptor subtypes isolated from chicken retinal explants, 3 replicates per sample
Project description:We investigated the ability of transferrin receptor1 (TfRc) knockout cells to populate different domains of the developing kidney by using a chimeric approach. The TfRc cells developed into all segments of the developing nephron, but there was a relative exclusion from the ureteric bud and a positive bias towards the stromal compartment. Here we conducted a microarray analysis of differential gene expression between TfRc deficient and wild type (wt) cells in chimeric embryonic kidneys derived from embryos created by blastocyst injection of wt blastocysts with TfRc-/- green fluorescent protein-expressing (GFP+) embryonic stem cells. Experiment Overall Design: Following blastocyst injection of 3-5 TfRc-/- GFP+ embryonic stem cells in wt blstocysts, we harvested the chimeric kidney at day E15.5 and separated the TfRc-/- GFP+ cell population from wt GFP- cell population by using fluorescence activated cell sorting. Biotinlyated cRNA was prepared from the isolated cells and hybridized to Mouse Genome 430 2.0 Arrays (Affymetrix) according to standard protocols.