MiR-125b: A Rheostat of Growth versus Stress-Induced MAPKs That Governs Stemness and OncomiR Addiction in Skin
ABSTRACT: We analyze the globel gene expression changes in the tumor initiating cells of regressing miR-125b addicted tumors after oncomiR withdrawal For Histone-H2BGFP expression in DTG tumor cells, the U6 promoter was deleted in the PLKO-PGK-H2B-GFP vector throughNdeI-AgeI digestion, Quick Blunting Kit treatment (NEB), and self-ligation. The resulting PLNA-PGK-H2BGFP plasmid was packaged into lentivirus and used to infect ~1x106freshly sorted α6hiβ1hi DTG tumor cells. After 30 min, cells were then extensively washed and immediately engrafted onto backskins of Nude mice by intradermal transplantation. GFP+α6hiβ1hicells were FACS-isolated from resulting tumors and then serially transplanted as above. For RNA seq analysis of the miR-125b addicted tumor regression process, H2BGFP labeled DTG tumor cells were intradermally engrafted onto backskins of Nude mice (1x104cells/site). Tumors were allowed to grow to ~1cm diameter. Mice were then taken Off Dox by transferring them to regular food for 0, 4, 7 days. GFP+α6hiβ1hiwere then FACS-isolated from the tumors. Two or three independent replicates were collected for each time point. Total RNAswere extracted from the FACS-sorted cells using the miRNeasy Mini Kit (Qiagen) according to the vender’s protocol. Expression of miR-125b in each sample was quantified by RT-PCR using TaqMan MicroRNA Assays (Applied Biosystems). For RNA seq, RNA samples were submitted to the Genomics Resources Core Facility of the Weill Cornell Medical College for library construction using IlluminaTruSeq Stranded mRNA Sample Prep Kit and then sequencing using Illumina HiSeq2000. Resultswere analyzed via the Galaxy web platform using TopHat for initiate mapping and Cufflinks for transcripts assembling and expression level estimation (Computing FPKM: fragments per kilobase of exon per million fragments mapped). The MM9 genome assembly (UCSC Genome Browser) was used as reference genome for all analyses. Low expression genes
Project description:Increasing evidence suggests that microRNAs may play important roles in regulating self-renewal and differentiation in mammalian stem cells (SCs). Here, we explore this issue in skin. We first characterize microRNA expression profiles of skin SCs versus their committed proliferative progenies and identify a microRNA subset associating with “stemness”. Of these, miR-125b is dramatically downregulated in early SC-progeny. We engineer an inducible mice system and show that when miR-125b is sustained in SC-progenies, tissue balance is reversibly skewed towards stemness at the expense of epidermal, oil-gland and HF differentiation. Using gain-and-loss of function in vitro, we further implicate miR-125b as a repressor of SC differentiation. In vivo, transcripts repressed upon miR-125b induction are enriched >700% for predicted miR-125b targets normally downregulated upon SC-lineage commitment. We verify some of these miR-125b targets, and show that Blimp1 and VDR in particular can account for many tissue imbalances we see when miR-125b is deregulated. We used microarrays to compare the global miRNA expression profile of P4 stage hair follicle ORS cells from DTG (K14-rtTA,TRE-miR-125b) and control littermates. Hair follicle cells were isolated from P4 Backskin (Dox since P3 for 24hrs) of DTG (K14-rtTA/TRE-miR-125b/K14-H2BGFP), TRE (TRE-miR-125b/K14-H2BGFP), KrtA (K14-rtTA/K14-H2BGFP) as following: interfollicular epidermis sheet was pealed from hair follicle & dermis after dispase treatment.The hair follicle & dermis were first digested by collagenase (Sigma). Intact hair follicles were separated from dermal cells by low speed spinning (20g). The hair follicles were then digested by Trypsin and filtered by 40 µm cell strainers. The isolated hair follicle cells were FACS sorted. During FACS, cells were first gated against CD34 (endothelial cells), CD45 (immune cells), CD114 (melanocytes) and DAPI (dead cells). ORS cells were sorted from the remaining cells as α6HiGFPHi.
Project description:This SuperSeries is composed of the following subset Series: GSE26393: Expression data of P4 stage hair follicle early bulge and non-bulge ORS cells GSE26394: Gene Expression data of P4 stage hair follicle ORS cells from DTG (K14-rtTA,TRE-miR-125b) and control littermates GSE26395: miRNA Expression data of P4 stage hair follicle ORS cells from DTG (K14-rtTA,TRE-miR-125b) and control littermates Refer to individual Series
Project description:Increasing evidence suggests that microRNAs may play important roles in regulating self-renewal and differentiation in mammalian stem cells (SCs). Here, we explore this issue in skin. We first characterize microRNA expression profiles of skin SCs versus their committed proliferative progenies and identify a microRNA subset associating with “stemness”. Of these, miR-125b is dramatically downregulated in early SC-progeny. We engineer an inducible mice system and show that when miR-125b is sustained in SC-progenies, tissue balance is reversibly skewed towards stemness at the expense of epidermal, oil-gland and HF differentiation. Using gain-and-loss of function in vitro, we further implicate miR-125b as a repressor of SC differentiation. In vivo, transcripts repressed upon miR-125b induction are enriched >700% for predicted miR-125b targets normally downregulated upon SC-lineage commitment. We verify some of these miR-125b targets, and show that Blimp1 and VDR in particular can account for many tissue imbalances we see when miR-125b is deregulated. We used microarrays to compare the global gene expression profile of P4 stage hair follicle ORS cells from DTG (K14-rtTA,TRE-miR-125b) and control littermates. Hair follicle cells were isolated from P4 Backskin of K14-RFP/Sox9-EGFP double transgenic mice as following: interfollicular epidermis sheet was pealed from hair follicle & dermis after dispase treatment. The hair follicle & dermis were first digested by collagenase (Sigma). Intact hair follicles were separated from dermal cells by low speed spinning (20g). The hair follicles were then digested by Trypsin and filtered by 40 µm cell strainers. The isolated hair follicle cells were FACS sorted. Dead cells and large differentiated cells were excluded based on DAPI and side scattering. Early bulge cells were gated as GFPHi,RFPHi. Non-bulge ORS cells were gated as GFP-, RFPHi.
Project description:The interior of the neuronal cell nucleus is a highly organized 3-dimensional (3D) structure in which regions of the genome that are millions of bases apart participate in specialized sub-structures with dedicated functions. To investigate neuronal chromatin organization and dynamics in vivo, we generated bitransgenic mice that express histone GFP-tagged H2B in principal neurons of the forebrain. Surprisingly, the expression of this chimeric histone in mature neurons causes chromocenter declustering and disrupts the association of heterochromatin with the nuclear lamina. The loss of these structures does not affect neuronal viability but is associated with specific transcriptional and behavioral deficits related to serotonergic dysfunction. Overall, our results demonstrate that the 3D-organization of chromatin in the neuronal nucleus supports an additional level of epigenetic regulation of gene expression that critically influences neuronal function and indicate that some loci associated with neuropsychiatric disorders may be particularly sensitive to changes in chromatin architecture. Genome-wide profiling by high throughput sequencing of H3K27me3 in the adult hippocampus of CaMKII-tTA/tetO-H2BGFP (H2BGFP) and their wild-type littermates mice (WT). Chromatin immunoprecipitation (ChIP) was carried out using pooled hippocampal tissue from 3 mice (one hippocampus per mouse). One DNA library was constructed per genotype. Each DNA library was prepared from pooled immunoprecipitated DNA from 4 independent ChIP assays. In total, tissue from 12 different mice was used to prepare each DNA library. 60% of a lane was used to perform single end (1x50bp) multiplex sequencing in HiSeq 2500 apparatus (Illumina). Each library, was sequenced in duplicate (in two independent sequencing runs. Technical replicates).
Project description:We identify numerous miR-203 in vivo targets that are highly enriched for the promotion of cell cycle and cell division. Importantly, individual targets including p63, Skp2 and Msi2 play distinct roles downstream of miR-203 to regulate the cell cycle and long-term proliferation. Together, our findings reveal rapid and widespread impact of miR-203 on the self-renewal program during the epidermal differentiation and provide mechanistic insights for the potent role of miR-203 where coordinated repression of multiple targets is required for the function of this miRNA. We used microarrays to measure transcriptome changes upon miR-203's induction in mouse skin and identified new targets of miR-203. We use two pairs of biological duplicates to perform the microarray analysis from the epidermal samples harvested from K14-rtTA/TRE-miR-203/K14-H2BGFP (DP) and TRE-miR-203/K14-H2BGFP (SP) littermates at P4, 24h after the Dox injection.
Project description:The interior of the eukaryotic cell nucleus is a highly organized 3D structure. In mature hippocampal and cortical pyramidal neurons, transcriptionally silent DNA is typically compacted in a few clusters referred to as chromocenters that are strongly stained with DNA intercalating agents like DAPI and whose function is still uncertain. We found that this 3D structure was severely disrupted by the incorporation of the chimeric histone H2BGFP into neuronal chromatin. Experiments in inducible and forebrain restricted bitransgenic mice demonstrated that the expression of this histone alters the higher-order organization of neuronal heterochromatin and causes a complex behavioral phenotype that includes hyperactivity, and social interaction, prepulse inhibition and cognitive defects. This phenotype was associated with highly specific transcriptional deficits that affected several serotonin receptor genes located at the edge of gene desert regions. Pharmacological and electrophysiological experiments indicate that this epigenetically-induced hyposerotonergic state may underlie the behavioral defects. Our results suggest a new role for perinuclear heterochromatin and chromocenter organization in the epigenetic regulation of neuronal gene expression and mental illness. We used microarrays to detect differential gene expression in transgenic mice expressing histone H2BGFP in the forebrain. We obtained triplicate samples (biological replicates) of either genotype (wild-type and H2BGFP mice). Each sample contained pooled total RNA from the hippocampi of 2 three-month old genotype-matched mice.
Project description:Axin2-expressing calvarial suture stem cells can contribute to calvarial development, homeostatic maintenance, repair, and regeneration. We used microarray to examine the gene expression profiles of Axin2-expressing suture stem cells and Axin2-negative cells in suture mesenchyme. Three of Axin2+/GFP+ and three of Axin2-/GFP- cell samples were collected from mice carrying Axin2rtTA and TREH2BGFP transgenes. Each samples were isolated from 6-8 Axin2rtTA; TRE-H2BGFP mice and sorted by the GFP intensity.
Project description:Hair follicle matrix, outer root sheath, dermal papilla cells and melanocytes and a dermal fraction enriched in fibroblasts were FACS isolated from 4d backskins. Targets from two biological replicates of each were generated and the expression profiles were determined using Affymetrix Mouse Genechip 430A arrays. Comparisons between the sample groups allow the identification of cell-type specific genes. Experiment Overall Design: Mx, ORS, DF, DP and Mc were FACSorted from Lef1-RFP/K14-H2BGFP mice from 4 day old backskins
Project description:Gene regulation by DNA binding small molecules could have important therapeutic applications. This study reports the investigation of a DNA-binding pyrrole-imidazole polyamide targeted to bind the DNA sequence 5’-WGGWWW-3’ with reference to its potency in a subcutaneous xenograft tumor model. The molecule is capable of trafficking to the tumor site following subcutaneous injection and modulates transcription of select genes in vivo. A FITC-labeled analogue of this polyamide can be detected in tumor-derived cells by confocal microscopy. RNA deep sequencing (RNA-seq) of tumor tissue allowed the identification of further affected genes, a representative panel of which were interrogated by qRT-PCR and correlated with cell culture expression levels. Xenografts. Grafting with A549-luc-C8. Experiments were performed in female SCID-beige mice (Charles River) between 8 and 12 weeks of age. Cells were injected into the left flank area of the animals as suspensions of 25 x 106 mL-1 in RPMI, 200 µL per injection. Treatment and tumor proliferation monitoring. Mice were treated following the schedule delineated in treatment protocol. Tumor proliferation was monitored using the XENOGEN imaging device. The animals were anesthetized with 2 5 % isoflurane and subsequently transferred to the imaging chamber, whereupon the isoflurane levels were reduced to 1-2.5 %. The floor of the imager was heated to +37 ºC to avoid hypothermia. Breathing frequency was monitored and not allowed to drop below 1 s-1, adjusting the isoflurane levels accordingly at all times. Endpoint criteria and euthanasia. Animal endpoint criteria encompassed weight loss of over 15 %, restriction of motor function by the engrafted tumor, dehydration of over 10 % and moribund behavior. Where appropriate, the animals were euthanized by asphyxiation in a CO2 chamber. Tumor tissue harvest. Animals were resected and tumors excised using standard forceps, scissors and surgical blades. The tumors were combined into one sample per condition and mechanically sheared in TRIZOL, employing a specialized device (tissue tearer, model 985370). Total RNA workup was performed following the standard TRIZOL procedure, followed by a DNAse digest.
Project description:To better understand the mechanisms of blockage of myeloid differentiation and apoptosis and induction of proliferation by miR-125b, we preceded to identify miR-125b target genes involved in these pathways. We analyzed the total cellular gene expression pattern by RNA-sequencing of the parental 32Dclone3 myeloid cell line and that ectopically expressing miR-125b. We generated four cDNA libraries corresponding to duplicates of miR-125b and control cells. Compare the gene expression level in vector transduced 32Dclone3 cells with that in miR-125b transduced 32Dclone3 cells.