Next-generation sequencing analysis of chemically induced neurons from wild type (WT), Actb+/- (HET) and Actb-/- (KO) mouse embryonic fibroblasts (MEFs)
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ABSTRACT: Purpose: The goals of this study are to use NGS to perform transcriptome profiling (RNA-seq) to find the difference of the transcriptomes of chemically induced neurons from wild type (WT), Actb+/- (HET) and Actb-/- (KO) mouse embryonic fibroblasts. Methods: MEFs were reprogramed into neurons by small chemical cocktails. Small chemical molecules were dissolved and diluted in DMSO and used at the following final concentrations: ISX9: 20 mM; Forskolin: 50 mM; CHIR99021: 20 mM; and I-BET151: 2 mM. In addition to the small molecules, the neuron induction medium (Neurobasal Medium) contains the following supplements: N2 (1X) and B27 (2X) supplements, GlutaMAX (1X), penicillin-streptomycin (100 µg/ml), bFGF (20 ng/ml), 100 µM cAMP, Non-essential Amino Acid (1X) and Trace element B (1X). MEFs were seeded to Matrigel-coated plate (1:30 dilution in pre-cold PBS and coat overnight at 4 oC, at a density of 200,000 cells per well in 6-well plate and 10,000 cells/well in 96 well plate. The MEFs were cultured in DMEM until confluent. When the cells are confluent, the DMEM was replaced with neuron induction medium with 4 small molecules. The induction medium was refreshed every two days for the first week and every 3 days for the remaining induction period until day 20. 3 biological replicates of total RNA were used for RNA-seq library preparation. Results: Using an optimized data analysis workflow, we identified neuronal gene programs induced during direct reprograming. The induction of neuronal programs were impaired in neurons from Actb-/- mouse embryonic fibroblasts. Conclusions: Our study shows that neuronal program induction was impaired in chemically induced neurons from Actb-/- mouse embryonic fibroblasts.
Project description:The cytoplasmic actin proteins, beta- and gamma-actin, are 99% identical but perform non-redundant functions. Genes encoding the cytoplasmic actins, Actb and Actg1, respectively, are less similar but still share 89% of their nucleotide sequences. Knockout (KO) of Actb by deletion of first coding exons 2 and 3 in mice is embryonic lethal while KO embryonic fibroblasts (MEFs) fail to proliferate. In contrast, KO of Actg1 is viable but mice lacking Actg1 present with increased perinatal lethality and Actg1 KO MEFs present with a much milder defect in cell proliferation. Recent studies have identified important protein-independent functions for both Actb and Actg1 and demonstrate that deletions within the Actb nucleotide sequence, and not loss of the beta-actin protein, cause the most severe phenotypes in KO mice and cells. Here, we use a multi-omics approach to better understand what drives the phenotypes of Actb KO MEFs. RNA-sequencing and mass spectrometry of Actb KO MEFs reveal largescale changes to the transcriptome, proteome, and phosphoproteome. Pathway analysis of genes and proteins differentially expressed upon Actb KO shows widespread dysregulation of genes involved in the cell cycle. Together, these data suggest novel, protein-independent roles for Actb in regulating gene expression associated with control of cell proliferation.
Project description:Investigation of DNA methlation changing in thymidine treatment-induced MEFs. Mouse embryonic fibroblasts (MEFs) were obtained at E14.5 embryos and supplied with Dulbecco’s modified Eagle’s medium (DMEM) (Invitrogen) with 15% FBS, 100 μg/ml streptomycin and 100 U/ml penicillin. Potential hematopoietic progenitor cells (CD45+CD41+CD31+c-Kit+) were negatively selected with Biotin labeled anti-CD45, anti-CD31, anti-CD41 and anti-c-Kit antibodies by magnetic beads. Hereafter, treated MEFs are referred to as 4neg MEFs for initiation of induction. 4neg MEFs were seeded on mitomycin (MMC)-treated MEFs as feeder cells and cultured in DMEM with 15% FBS, 100 μg/ml streptomycin, 100 U/ml penicillin, 2 mM L-glutamine, 0.1 mM non-essential amino acids and 100 μM thymidine as induction medium for 2 days followed with analysis
Project description:Investigation of differentially expressed genes in thymidine treatment-induced MEFs. Mouse embryonic fibroblasts (MEFs) were obtained at E14.5 embryos and supplied with Dulbecco’s modified Eagle’s medium (DMEM) (Invitrogen) with 15% FBS, 100 μg/ml streptomycin and 100 U/ml penicillin. Potential hematopoietic progenitor cells (CD45+CD41+CD31+c-Kit+) were negatively selected with Biotin labeled anti-CD45, anti-CD31, anti-CD41 and anti-c-Kit antibodies by magnetic beads. Hereafter, treated MEFs are referred to as 4neg MEFs for initiation of induction. 4neg MEFs were seeded on mitomycin (MMC)-treated MEFs as feeder cells and cultured in DMEM with 15% FBS, 100 μg/ml streptomycin, 100 U/ml penicillin, 2 mM L-glutamine, 0.1 mM non-essential amino acids and 100 μM thymidine as induction medium for 6 days. Cells were then trypsinized and re-seeded to new feeder cells for another 6 days. Cells were positively selected with Biotin labeled anti-CD45 by magnetic beads followed with analysis.
Project description:Using Chromatin-immunoprecipitation and NGS, we investigated the binding of TFAM protein at mitochondrial genome between Actb+/+ Wild Type (WT) and Actb-/- (KO) Mouse Embryonic Fibroblast
Project description:RNA sequencing of Wild Type (WT) and Actb-/- (KO) Mouse Embryonic Fibroblasts. Total RNA was sequenced to analyse noncoding transcripts and repeats
Project description:Cortical rat neuronal culture, lysis and proteolytic digestion Primary rat cortical neurons were generated from E18 Sprague-Dawley rat embryos with minor modifications (Swanger, Mattheyses et al. 2015, Henderson, Greathouse et al. 2019). Neurons were cultured at a density of 4x105 cells per well in 12-well culture plates (Fisher Scientific, catalog no. 353043). Neurons were cultured in Neurobasal medium (Fisher Scientific, catalog no. 21103-049) supplemented with B27 (Fisher Scientific, catalog no.17504-044). Culture maintenance included a half media change every 2-3 days. At DIV 14, neurons were either treated with 150 ng/mL recombinant NRN1 protein (Abcam, ab69755) or vehicle treated with diH2O for 6 hours. NRN1 concentration was chosen based on published data that identified a plateau in exogenous NRN1 induced effects on transient potassium currents at 150 ng/mL (Yao et al., 2012). After 6 hours neurons were washed 2x with 1 mL 1X phosphate-buffered saline (PBS). To harvest cells, 1 mL 1X PBS + protease inhibitor (Fisher Scientific, catalog no. 78426) was added and cells were centrifuged for 2300rpm for 5 minutes at 4°C. Cell pellets were lysed in 200uL 8M urea buffer and HALT protease and phosphatase inhibitor cocktail (1x final concentration). Lysates were sonicated with a probe sonicator 3 times for 10 s with 10 s intervals at 30% amplitude and cleared of cellular debris by centrifugation in a tabletop centrifuge at 18,000 rcf for 3 minutes at 4° C. Protein concentration was determined by BCA assay and one-dimensional SDS-PAGE gels were run followed by Coomassie blue staining as quality control for protein integrity and equal loading before proceeding to protein digestion. Protein homogenates (50 µg) were diluted with 50 mM NH4HCO3 to a final concentration of less than 2 M urea and then treated with 1 mM dithiothreitol (DTT) at 25°C for 30 minutes, followed by 5 mM iodoacetimide (IAA) at 25°C for 30 minutes in the dark. Protein was digested with 1:100 (w/w) lysyl endopeptidase (Wako) at 25°C for 2 hours and further digested overnight with 1:50 (w/w) trypsin (Pierce) at 25°C. Resulting peptides were desalted with a Sep-Pak C18 column (Waters) and dried under vacuum.
Project description:We have developed a serum-free chemical defined medium, namely 6C, that can directly convert mouse embryonic fibroblast (MEFs), glia cells into neurons in vitro. Human cells such as human foreskin fibroblast(HHFs), Hela cells and born marrow derived mesenchymal stem cells (BM-hMSC) can also be converted into neuron-like cells by this medium with some modification such as including several other small molecules. To understand the possible mechanisms, the transdifferentiation of MEFs by 6C was chosen as a model system and gene profiling at different time point during the conversion was carried out by RNA sequencing using Illumina MiSeq. MEFs was maintained in MEF medium (DMEM containing 10% FBS, 1mM Glutamax and 100X NEAA), to start the induction, the culture medium was shift to 6C and marked as day 0, neurons could be generated in day 15. mRNA samples was collected at day 0, 2, 5, 10, 15 during the process, with cell lysed by Trizol and mRNA enriched by Illumina TruSeq RNA Sample Preparation v2 kit. We find that most cell cycle related genes were up regulated during the first few days of induction, while many Notch pathway genes up regulated during the later phase of this process. The RNA sequencing data provided important cues for further study on the mechanisms of the direct neuronal induction process.
Project description:Using Chromatin-immunoprecipitation and NGS, we profiled the genome-wdie H3K9Me3, H3K27Me and Brg1 distribution between Wild Type (Wt) and Actb-/- (KNO) Mouse Embryonic Fibroblast