Functional deficits persist after spinal cord injury (SCI) because axons in the adult mammalian central nervous system (CNS) fail to regenerate. However, modest levels of spontaneous functional recovery are typically observed after trauma, and are thought to be mediated by the plasticity of intact circuits. The mechanisms underlying intact circuit plasticity are not delineated. Here, we characterize the in vivo transcriptome of sprouting intact neurons from ngr1 null mice after partial SCI. We identify the lysophosphatidic acid signaling modulators Lppr1 and Lpar1 as intrinsic axon growth modulators for intact corticospinal motor neurons after adjacent injury. Furthermore, in vivo Lpar1 inhibition or Lppr1 overexpression enhances sprouting of intact corticospinal tract axons and yields greater functional recovery after unilateral brainstem lesion in wild type mice. Thus, the transcriptional profile of injury-induced sprouting of intact neurons reveals targets for therapeutic enhancement of axon growth initiation and new synapse formation. Overall design: GFP labeled Corticospinal motor neurons (CSMNs) were harvetsed via laser capture microdissection to assess gene expression between populations that were quiescent and those that initated a functional axon growth response.
Identification of Intrinsic Axon Growth Modulators for Intact CNS Neurons after Injury.
Specimen part, Cell line, Subject
View SamplesThe alimentary tract contains a diffuse endocrine system comprising enteroendocrine cells that secrete peptides or biogenic amines to regulate digestion, insulin secretion, food intake, and energy homeostasis. Lineage analysis in the stomach revealed that a significant fraction of endocrine cells in the gastric corpus did not arise from neurogenin3-expressing cells, unlike enteroendocrine cells elsewhere in the digestive tract. We aimed to isolate enriched serotonin-secreting and enterochromaffin-like (ECL) cells from the stomach and to clarify their cellular origin. We used Neurod1 and Neurog3 lineage analysis, and examined differentiation of serotonin-producing and ECL cells in stomach tissues of Neurod1-cre;ROSAtdTom, Tph1-CFP, c-Kitwsh/wsh, and Neurog3Cre;ROSAtdTom mice, by immunohistochemistry. We used fluorescence-activated cell sorting to isolate each cell type for gene expression analysis. We performed RNA-seq analysis of ECL cells. Neither serotonin-secreting nor ECL cells of the corpus arose from cells expressing Neurod1. Serotonin-secreting cells expressed a number of mast cell genes, but not genes associated with endocrine differentiation; they did not develop in c-Kitwsh/wsh mice and were labeled with transplanted bone marrow cells. RNA-seq analysis of ECL cells revealed high expression levels of many genes common to endocrine cells including transcription factors, hormones, ion channels, and solute transporters but not markers of bone marrow cells. Overall design: We used fluorescence-activated cell sorting to isolate Hdc+ cells from stomach corpus and performed RNA-seq for gene expression analysis to determine the origin of those cells.
Distinct cellular origins for serotonin-expressing and enterochromaffin-like cells in the gastric corpus.
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View SamplesThis study demonstrates that siRNA off-targets (e.g. 3'UTR off-targets), can be significantly reduced when cells are treated with a relatively low dose of siRNA (e.g. 1nM) that is sufficient to effectively silence the intended target.
siRNA off-target effects can be reduced at concentrations that match their individual potency.
Cell line
View SamplesThe transcriptional repressor BLIMP1 is a master regulator of B and T cell differentiation. To examine the role of BLIMP1 in innate immunity we used a conditional knockout (CKO) of Blimp1 in myeloid cells and found that Blimp1 CKO mice were protected from lethal infection induced by Listeria monocytogenes. Transcriptome analysis of Blimp1 CKO macrophages identified the murine chemokine (C-C motif) ligand 8, CCL8 as a direct target of Blimp1-mediated transcriptional repression in these cells. BLIMP1-deficient macrophages expressed elevated levels of Ccl8 and consequently Blimp1 CKO mice had higher levels of circulating CCL8 resulting in increased neutrophils in the peripheral blood, promoting a more aggressive anti-bacterial response. Mice lacking the Ccl8 gene were more susceptible to L. monocytogenes infection than wild type mice. While CCL8 failed to recruit neutrophils directly, it was chemotactic for / T cells and CCL8-responsive / T cells were enriched for IL-17F. Finally, CCL8-mediated enhanced clearance of L. monocytogenes was dependent on / T cells. Collectively, these data reveal an important role for BLIMP1 in modulating host-defenses by suppressing expression of the chemokine CCL8.
The transcriptional repressor BLIMP1 curbs host defenses by suppressing expression of the chemokine CCL8.
Specimen part
View SamplesAn inducible program of inflammatory gene expression is central to antimicrobial defenses. This response is controlled by a collaboration involving signal-dependent activation of transcription factors, transcriptional co-regulators, and chromatin-modifying factors. We have identified a long noncoding RNA (lncRNA) that acts as a key regulator of this inflammatory response. Pattern recognition receptors such as the Toll-like receptors induce the expression of numerous lncRNAs. One of these, lincRNA-Cox2, mediates both the activation and repression of distinct classes of immune genes. Transcriptional repression of target genes is dependent on interactions of lincRNA-Cox2 with heterogeneous nuclear ribonucleoprotein A/B and A2/B1. Collectively, these studies unveil a central role of lincRNA-Cox2 as a broad-acting regulatory component of the circuit that controls the inflammatory response Overall design: Examination of Mus musculus (C57BL/6 background) gene expression changes following stimulation with Pam3Cys4 in presence or absence of shRNA specifically targetting lncRNA-COX2
A long noncoding RNA mediates both activation and repression of immune response genes.
Specimen part, Cell line, Subject
View SamplesThousands of long non-coding RNAs (lncRNAs) have been identified in the human genome, many of which are not conserved in lower mammals. The majority of these lncRNAs remain functionally uncharacterized and may have important implications in human physiology and disease. Here, we identify a primate-specific lncRNA, CHROME, which is increased in the plasma and atherosclerotic plaques of individuals with coronary artery disease compared to healthy controls. Using a loss-of-function approach, we show that CHROME functions as a competing endogenous RNA of microRNAs and regulates the concentration and biological functions of target genes. Overall design: We used three replicate samples of HEPG2 cells that were treated with shRNA for CHROME compated to three replicate control samples.
The long noncoding RNA CHROME regulates cholesterol homeostasis in primate.
Specimen part, Cell line, Subject
View SamplesDeep sequencing has revealed that epigenetic modifiers are the most mutated genes in acute myeloid leukemia (AML). Thus, elucidating epigenetic dysregulation in AML is crucial to understand disease mechanisms. Here, we demonstrate that Metal Response Element Binding Transcription Factor 2/Polycomblike 2 (MTF2/PCL2) plays a fundamental role in the Polycomb repressive complex 2 (PRC2) and that its loss elicits an altered epigenetic state underlying refractory AML. Unbiased systems analyses identified the loss of MTF2-PRC2 repression of MDM2 as central to, and therefore a biomarker for, refractory AML. Thus, immature MTF2- deficient CD34+CD38- cells overexpress MDM2, thereby inhibiting p53 that leads to chemoresistance due to defects in cell cycle regulation and apoptosis. Targeting this dysregulated signaling pathway by MTF2 overexpression or MDM2 inhibitors sensitized refractory patient leukemic cells to induction chemotherapeutics and prevented relapse in AML patient-derived xenograft (PDX) mice. Therefore, we have uncovered a direct epigenetic mechanism by which MTF2 functions as a tumor suppressor required for AML chemotherapeutic sensitivity and identified a potential therapeutic strategy to treat refractory AML. Overall design: Fold change analysis between treatment and control
Targeting the MTF2-MDM2 Axis Sensitizes Refractory Acute Myeloid Leukemia to Chemotherapy.
Specimen part, Subject
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