Detailed information about stage-specific changes in gene expression is crucial for understanding the gene regulatory networks underlying development and the various signal transduction pathways contributing to morphogenesis. Here, we describe the global gene expression dynamics during early murine limb development, when cartilage, tendons, muscle, joints, vasculature, and nerves are specified and the musculoskeletal system of the limbs is established. We used whole-genome microarrays to identify genes with differential expression at 5 stages of limb development (E9.5 to 13.5), during fore-limb and hind-limb patterning. We found that the onset of limb formation is characterized by an up-regulation of transcription factors, which is followed by a massive activation of genes during E10.5 and E11.5 which tampers off at later time points. Among 3520 genes identified as significantly up-regulated in the limb, we find ~30% to be novel, dramatically expanding the repertoire of candidate genes likely to function in the limb. Hierarchical and stage-specific clustering identified expression profiles that correlate with functional programs during limb development and are likely to provide new insights into specific tissue patterning processes. Here we provide for the first time, a comprehensve analysis of developmentally regulated genes during murine limb development, and provide some novel insights into the expression dynamics governing limb morphogenesis.
Global gene expression analysis of murine limb development.
Specimen part
View SamplesAmyotrophic lateral sclerosis (ALS) is a paralytic degenerative disease of the nervous system. In the SOD1 mouse model of ALS we found loss of the molecular and functional microglia signature associated with pronounced expression of miR-155 in SOD1 mice. We also found increased expression of miR-155 in the spinal cord of ALS subjects. Genetic ablation of miR-155 increased survival in SOD1 mice and reversed the abnormal microglial and monocyte molecular signature. In addition, dysregulated proteins in the spinal cord of SOD1 mice that we identified in human ALS spinal cords and CSF were restored in SOD1G93A/miR155-/- mice. Treatment of SOD1 mice with anti-miR-155 SOD1 mice injected systemically or into the cerebrospinal fluid prolonged survival and restored the microglial unique genetic and microRNA profiles. Our findings provide a new avenue for immune based therapy of ALS by targeting miR-155. Overall design: Total RNA was isolated from whole lumbar spinal cord homogenate from healthy control donors without known neurologic diseases and sporadic and familial ALS.
Targeting miR-155 restores abnormal microglia and attenuates disease in SOD1 mice.
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View SamplesInjuries to the anterior cruciate ligament (ACL) often result in post-traumatic osteoarthritis (PTOA). PTOA accounts for ~12% of all osteoarthritis (OA) cases, yet the mechanisms contributing to OA after joint injury are not well understood. To better understand the molecular mechanisms behind PTOA development following ACL injury, we profiled ACL injury-induced gene expression changes in knee joints of three mouse strains with varying susceptibility to PTOA: STR/ort (highly susceptible), C57BL/6 (moderately susceptible) and super-healer MRL/MpJ (not susceptible) and identified genes differentially expressed between these strains at 0-day [before injury], 1-day, 1-week, and 2-weeks post-injury. This study highlights many new potential therapeutic targets and OA biomarkers. Overall design: Comparative transcriptomics to understand the molecular changes associated with early stages of PTOA development in STR/ort, C57BL/6 and MRL/MpJ mice and to identify genes that contribute to increased OA susceptibility in STR/ort and resistance to PTOA in MRL/MpJ.
Comparative Transcriptomics Identifies Novel Genes and Pathways Involved in Post-Traumatic Osteoarthritis Development and Progression.
Age, Specimen part, Cell line, Treatment, Subject
View SamplesWNT signaling is critical in most aspects of skeletal development and homeostasis, and antagonists of WNT signaling are emergning as key regulatory proteins with great promise as therapeutic agents for bone disorders. Until recently Sost and its paralog Sostdc1 have been described as growth factors with highly restricted expression in the adult where Sost was assumed 'osteocyte-' and Sostdc1 'kidney-' specific. Here we show that these two proteins emerged throgh ancestral genome duplication and their expression patterns have diverged to span complimentary domains in most organ systems including musculoskeletal, cardiovascular, nervous, digestive, reproductive and respiratory. In the developing limb, Sost and Sostdc1 display dynamic expression patterns with Sost being restricted to the distal ectoderm and Sostdc1 to the proximal ectoderm and the mesenchyme.
Sost and its paralog Sostdc1 coordinate digit number in a Gli3-dependent manner.
Specimen part
View SamplesWe report the application of low cell number sequencing of identifiable Drosophila melanogaster neurons following behavior. We demonstate the feasibility of identifying the transcriptome of 5 Mushroom Body output Neurons and 2 classes of Kenyon Cells. We find these neurons display a diverse repertoire of receptors and signaling transcripts. This information alone seems to be enough to identify each class of neurons in the study. In additional we show that aversive long-term memory induces changes in gene transcript levels in a subset of these neurons. This study provides a framework for identifying neuronal classes in Drosophila melanogaster and gaining insight into the interplay between behavior and gene regulation. Overall design: 5 Mushroom Body output neurons and 2 classes of kenyon cells are used to look at general gene expression and changes following aversive long term memory. Paired control and trained animals were used and a minimum of 4 pairs up to 6 pairs. Animals were of the same background (w1118). Animals were aged and parental matched. Cells were harvested at the same chronological time for the animals across all experiments. All animals were exposed to 1 minute of each odor and 1 minute of a series of 12 5second 60V shocks. This was considered one block and then the animals had spaced training of each block so there was a 10 minute break between 8 blocks of training. Trained animals had an odor paired with a shock, control animals received the shock then the odor stimulus. All cells were harvested usign a patch pipet from living animals on an electrophysiology rig within a half hour of the end of training. Cells were amplified using the Clontech SMARTer Ultra Low Input RNA version 2 High Volume kit. 2 Brain samples were also collected and 3-4 whole fly samples for each genotype were collected to account for background differences across flies.
Cell-Type-Specific Transcriptome Analysis in the Drosophila Mushroom Body Reveals Memory-Related Changes in Gene Expression.
Subject
View SamplesBcl11a is a transcription factor known to regulate lymphoid and erythroid development. Recent bioinformatic analysis of global gene expression patterns has suggested a role for Bcl11a in the development of dendritic cell (DC) lineages. We tested this hypothesis by analyzing the development of DC and other lineages in Bcl11a(-/-) mice. We show that Bcl11a is required for expression of IL-7 receptor (IL-7R) and Flt3 in early hematopoietic progenitor cells. The loss of IL-7R(+) common lymphoid progenitors accounts for previously described lymphoid defects in Bcl11a(-/-) mice. In addition, we found severely decreased numbers of plasmacytoid dendritic cells (pDCs) in Bcl11a(-/-) fetal livers and in the bone marrow of Bcl11a(-/-) fetal liver chimeras. Moreover, Bcl11a(-/-) cells show severely impaired in vitro development of Flt3L-derived pDCs and classical DCs (cDCs). In contrast, we found normal in vitro development of DCs from Bcl11a(-/-) fetal liver cells treated with GM-CSF. These results suggest that the persistent cDC development observed in Bcl11a(-/-) fetal liver chimeras reflects derivation from a Bcl11a- and Flt3-independent pathway in vivo.
Bcl11a controls Flt3 expression in early hematopoietic progenitors and is required for pDC development in vivo.
Specimen part
View SamplesThe present study reveals LMYC and MXD1 as novel regulators of a transcriptional program that is modulated during the maturation of Batf3-dependent dendritic cells (also known as type I classical dendritic cells or cDC1s).
The MYCL and MXD1 transcription factors regulate the fitness of murine dendritic cells.
Specimen part
View SamplesWhile activation of canonical NF-?B signaling through the IKK complex is well studied, few regulators of NIK-dependent non-canonical p52 nuclear translocation have been identified. We discovered a novel role for cyclin dependent kinase 12 (CDK12) in transcriptionally regulating the non-canonical NF-?B pathway. High-content phenotypic screening identified a novel compound, 919278, which inhibits lymphotoxin ß receptor (LTßR)- and FN14-dependent p52 nuclear translocation, but not TNFa receptor (TNFR)-mediated, canonical NF-?B p65 nuclear translocation. Chemoproteomics identified cyclin dependent kinase 12 (CDK12) as the target of 919278. CDK12 inhibition by 919278, THZ1, or siRNA knock down all affect similar global transcriptional changes and prevent LTßR and FN14-dependent MAP3K14 (NIK) mRNA induction and subsequent protein accumulation. In addition, 919278 and THZ1 treatment reduce RNA Pol II CTD phosphorylation. This powerful approach of coupling a phenotypic screen with chemoproteomics revealed a novel regulatory pathway of the non-canonical NF-?B pathway that could serve as a therapeutic target in autoimmunity and cancer. Overall design: There are TWEAK stimulated and unstimulated conditions, 4hr and 24hr time points. 7 treatments (DMSO, BIO0702697, BIO0919278, BIO032202, NTsiRNA, siRNAs523626, siRNAs523629) in duplicates. In total, 56 sample were sequenced and analyzed.
CDK12-mediated transcriptional regulation of noncanonical NF-κB components is essential for signaling.
Cell line, Treatment, Subject, Time
View SamplesES cells differentiated in the presence of the Wnt inhibitor DKK1 fail to express the transcription factor Snail and undergo EMT or mesoderm differentiation. We generated an ES cell line, A2.snail, that induced Snail expression upon addition of doxycycline addition.
Snail promotes the cell-autonomous generation of Flk1(+) endothelial cells through the repression of the microRNA-200 family.
Specimen part, Cell line
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Zbtb46 expression distinguishes classical dendritic cells and their committed progenitors from other immune lineages.
Specimen part
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