scholarly journals Class IIa histone deacetylases link cAMP signaling to the myelin transcriptional program of Schwann cells

2018 ◽  
Vol 217 (4) ◽  
pp. 1249-1268 ◽  
Author(s):  
Clara Gomis-Coloma ◽  
Sergio Velasco-Aviles ◽  
Jose A. Gomez-Sanchez ◽  
Angeles Casillas-Bajo ◽  
Johannes Backs ◽  
...  
Keyword(s):  
Gene Expression ◽  
Schwann Cells ◽  
Histone Deacetylases ◽  
Adenosine Monophosphate ◽  
Conditional Knockout ◽  
Negative Regulator ◽  
Myelin Proteins ◽  
Camp Signaling ◽  
Transcriptional Program

Schwann cells respond to cyclic adenosine monophosphate (cAMP) halting proliferation and expressing myelin proteins. Here we show that cAMP signaling induces the nuclear shuttling of the class IIa histone deacetylase (HDAC)–4 in these cells, where it binds to the promoter and blocks the expression of c-Jun, a negative regulator of myelination. To do it, HDAC4 does not interfere with the transcriptional activity of MEF2. Instead, by interacting with NCoR1, it recruits HDAC3 and deacetylates histone 3 in the promoter of c-Jun, blocking gene expression. Importantly, this is enough to up-regulate Krox20 and start Schwann cell differentiation program–inducing myelin gene expression. Using conditional knockout mice, we also show that HDAC4 together with HDAC5 redundantly contribute to activate the myelin transcriptional program and the development of myelin sheath in vivo. We propose a model in which cAMP signaling shuttles class IIa HDACs into the nucleus of Schwann cells to regulate the initial steps of myelination in the peripheral nervous system.

scholarly journals The nucleoporin RanBP2 tethers the cAMP effector Epac1 and inhibits its catalytic activity

2011 ◽  
Vol 193 (6) ◽  
pp. 1009-1020 ◽  
Author(s):  
Martijn Gloerich ◽  
Marjolein J. Vliem ◽  
Esther Prummel ◽  
Lars A.T. Meijer ◽  
Marije G.A. Rensen ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Cyclic Adenosine Monophosphate ◽  
Adenosine Monophosphate ◽  
Negative Regulator ◽  
Camp Signaling ◽  
Nuclear Pore ◽  
Nucleotide Exchange ◽  
Nucleotide Exchange Factor ◽  
Wide Range

Cyclic adenosine monophosphate (cAMP) is a second messenger that relays a wide range of hormone responses. In this paper, we demonstrate that the nuclear pore component RanBP2 acts as a negative regulator of cAMP signaling through Epac1, a cAMP-regulated guanine nucleotide exchange factor for Rap. We show that Epac1 directly interacts with the zinc fingers (ZNFs) of RanBP2, tethering Epac1 to the nuclear pore complex (NPC). RanBP2 inhibits the catalytic activity of Epac1 in vitro by binding to its catalytic CDC25 homology domain. Accordingly, cellular depletion of RanBP2 releases Epac1 from the NPC and enhances cAMP-induced Rap activation and cell adhesion. Epac1 also is released upon phosphorylation of the ZNFs of RanBP2, demonstrating that the interaction can be regulated by posttranslational modification. These results reveal a novel mechanism of Epac1 regulation and elucidate an unexpected link between the NPC and cAMP signaling.

Production of the CYS3 regulator, a bZIP DNA-binding protein, is sufficient to induce sulfur gene expression in Neurospora crassa

1992 ◽  
Vol 12 (4) ◽  
pp. 1568-1577
Author(s):  
J V Paietta
Keyword(s):  
Gene Expression ◽  
Neurospora Crassa ◽  
Structural Gene ◽  
Control Point ◽  
Regulatory Protein ◽  
Negative Regulator ◽  
Temperature Sensitive ◽  
Cys3 Protein

The cys-3+ gene of Neurospora crassa encodes a bZIP (basic region-leucine zipper) regulatory protein that is essential for sulfur structural gene expression (e.g., ars-1+). Nuclear transcription assays confirmed that cys-3+ was under sulfur-regulated transcriptional control and that cys-3+ transcription was constitutive in sulfur controller (scon)-negative regulator mutants. Given these results, I have tested whether expression of cys-3+ under high-sulfur (repressing) conditions was sufficient to induce sulfur gene expression. The N. crassa beta-tubulin (tub) promoter was fused to the cys-3+ coding segment and used to transform a cys-3 deletion mutant. Function of the tub::cys-3 fusion in homokaryotic transformants grown under high-sulfur conditions was confirmed by Northern (RNA) and Western immunoblot analysis. The tub::cys-3 transformants showed arylsulfatase gene expression under normally repressing high-sulfur conditions. A tub::cys-3ts fusion encoding a temperature-sensitive CYS3 protein was used to confirm that the induced structural gene expression was due to CYS3 protein function. Constitutive CYS3 production did not induce scon-2+ expression under repressing conditions. In addition, a cys-3 promoter fusion to lacZ showed that CYS3 production was sufficient to induce its own expression and provides in vivo evidence for autoregulation. Finally, an apparent inhibitory effect observed with a strain carrying a point mutation at the cys-3 locus was examined by in vitro heterodimerization studies. These results support an interpretation of CYS3 as a transcriptional activator whose regulation is a crucial control point in the signal response pathway triggered by sulfur limitation.

Sex-dimorphic effects of progesterone and its reduced metabolites on gene expression of myelin proteins by rat Schwann cells

2006 ◽  
Vol 11 (2) ◽  
pp. 111-118 ◽  
Author(s):  
Valerio Magnaghi ◽  
Sergio Veiga ◽  
Marinella Ballabio ◽  
Lucas C. Gonzalez ◽  
Luis M. Garcia-Segura ◽  
...  
Keyword(s):  
Gene Expression ◽  
Schwann Cells ◽  
Myelin Proteins

scholarly journals Pharmacological and genetic activation of cAMP synthesis disrupts cholesterol utilization in Mycobacterium tuberculosis

2021 ◽  
Author(s):  
Kaley M. Wilburn ◽  
Christine R. Montague ◽  
Bo Qin ◽  
Ashley K. Woods ◽  
Melissa S. Love ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Adenylyl Cyclase ◽  
Cholesterol Metabolism ◽  
Cyclic Adenosine Monophosphate ◽  
Adenosine Monophosphate ◽  
Camp Signaling ◽  
Camp Synthesis ◽  
Pharmacokinetic Properties ◽  
Bacterial Utilization

There is a growing appreciation for the idea that bacterial utilization of host-derived lipids, including cholesterol, supports Mycobacterium tuberculosis (Mtb) pathogenesis. This has generated interest in identifying novel antibiotics that can disrupt cholesterol utilization by Mtb in vivo. Here we identify a novel small molecule agonist (V-59) of the Mtb adenylyl cyclase Rv1625c, which stimulates 3’, 5’-cyclic adenosine monophosphate (cAMP) synthesis and inhibits cholesterol utilization by Mtb. Similarly, using a complementary genetic approach that induces bacterial cAMP synthesis independent of Rv1625c, we demonstrate that inducing cAMP synthesis is sufficient to inhibit cholesterol utilization in Mtb. Although the physiological roles of individual adenylyl cyclase enzymes in Mtb are largely unknown, here we demonstrate that the transmembrane region of Rv1625c is required for cholesterol metabolism. Finally, in this work the pharmacokinetic properties of Rv1625c agonists are optimized, producing an orally-available Rv1625c agonist that impairs Mtb pathogenesis in infected mice. Collectively, this work demonstrates a novel role for Rv1625c and cAMP signaling in controlling cholesterol metabolism in Mtb and establishes that cAMP signaling can be pharmacologically manipulated for the development of new antibiotic strategies.

Adoptive Transfer of Nf1+/− Bone Marrow Is Sufficient for Neurofibroma Progression in Krox20;Nf1flox/flox Mice.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 3064-3064
Author(s):  
Fengchun Yang
Keyword(s):  
Bone Marrow ◽  
Mast Cells ◽  
Tumor Microenvironment ◽  
Schwann Cells ◽  
Genetic Disorder ◽  
Hematopoietic Cells ◽  
Tumor Formation ◽  
Conditional Knockout ◽  
Axial Tomography

Abstract Mutations in the NF1 tumor suppressor gene cause neurofibromatosis type 1 (NF1), a GTPase activating protein for Ras called neurofibromin. NF1 is a genetic disorder that affects approximately 250,000 individuals in the US, Europe, and Japan alone. Neurofibromas, the hallmark of NF1, are complex tumors characterized by tumorigenic Schwann cells, neoangiogenesis, fibrosis, and degranulating mast cells. Studies in experimental models have emphasized the role of inflammatory cells in altering the microenvironment and facilitating malignant outgrowth. Similarly, Parada (Science, 2002) found that nullizygosity of Nf1 in Schwann cells of conditional knockout mice (Krox20;Nf1flox/flox) was necessary but not sufficient for neurofibroma formation and haploinsufficiency of Nf1 in lineages within the tumor microenvironment was required for neurofibroma progression. We previously provided the first genetic, cellular, and biochemical evidence that haploinsufficiency of Nf1 alters Ras activity and cell fates in mast cells (JEM, 2000, 2001) and identified a mechanism underlying the recruitment of mast cells to tumorigenic Schwann cells (JCI 2003). However, it remains unclear whether Nf1 +/− bone marrow derived hematopoietic cells can directly contribute to neurofibroma formation in vivo. To address this question, Nf1+/− or wildtype (WT) EGFP+ bone marrow (BM) was adoptively transferred into lethally irradiated Krox20;Nf1flox/flox mice and cohorts were followed prospectively for tumor formation using positron emission tomography and computerized axial tomography. Mice transplanted with Nf1+/− but not WT BM developed progressive enlargement of the trigeminal nerve, dorsal root ganglia, peripheral nerves, and motor paralysis similar to Krox20;Nf1flox/− mice that are haploinsufficient at Nf1 in all lineages of the tumor microenvironment. Postmortem analysis revealed that Krox20;Nf1flox/flox mice transplanted with Nf1+/− BM had cellular neurofibromas containing Schwann cells, fibroblasts, blood vessels and mast cells, which closely resembled the cellular architecture of human neurofibromas. Mice transplanted with WT BM did not develop neurofibromas. These studies establish that recruitment of Nf1 +/− BM derived cells to the neurofibroma microenvironment is directly linked to neurofibroma formation and progression. Given our observations, therapies which prevent both the recruitment and the tumor promoting functions of Nf1 +/− hematopoietic cells in neurofibroma formation are currently being tested in vivo as pre-clinical trials.

scholarly journals In Vivo Activation of cAMP Signaling Induces Growth Arrest and Differentiation in Acute Promyelocytic Leukemia

2002 ◽  
Vol 196 (10) ◽  
pp. 1373-1380 ◽  
Author(s):  
Marie-Claude Guillemin ◽  
Emmanuel Raffoux ◽  
Dominique Vitoux ◽  
Scott Kogan ◽  
Hassane Soilihi ◽  
...  
Keyword(s):  
Acute Promyelocytic Leukemia ◽  
Myeloid Leukemia ◽  
Growth Arrest ◽  
Leukemia Cell ◽  
Cyclic Adenosine Monophosphate ◽  
Adenosine Monophosphate ◽  
Promyelocytic Leukemia ◽  
Camp Signaling ◽  
Resistant Mouse

Differentiation therapy for acute myeloid leukemia uses transcriptional modulators to reprogram cancer cells. The most relevant clinical example is acute promyelocytic leukemia (APL), which responds dramatically to either retinoic acid (RA) or arsenic trioxide (As2O3). In many myeloid leukemia cell lines, cyclic adenosine monophosphate (cAMP) triggers growth arrest, cell death, or differentiation, often in synergy with RA. Nevertheless, the toxicity of cAMP derivatives and lack of suitable models has hampered trials designed to assess the in vivo relevance of theses observations. We show that, in an APL cell line, cAMP analogs blocked cell growth and unraveled As2O3-triggered differentiation. Similarly, in RA-sensitive or RA-resistant mouse models of APL, continuous infusions of 8-chloro-cyclic adenosine monophosphate (8-Cl-cAMP) triggered major growth arrest, greatly enhanced both spontaneous and RA- or As2O3-induced differentiation and accelerated the restoration of normal hematopoiesis. Theophylline, a well-tolerated phosphodiesterase inhibitor which stabilizes endogenous cAMP, also impaired APL growth and enhanced spontaneous or As2O3-triggered cell differentiation in vivo. Accordingly, in an APL patient resistant to combined RA–As2O3 therapy, theophylline induced blast clearance and restored normal hematopoiesis. Taken together, these results demonstrate that in vivo activation of cAMP signaling contributes to APL clearance, independently of its RA-sensitivity, thus raising hopes that other myeloid leukemias may benefit from this therapeutic approach.

scholarly journals Upregulation of class I major histocompatibility complex gene expression in primary sensory neurons, satellite cells, and Schwann cells of mice in response to acute but not latent herpes simplex virus infection in vivo.

1994 ◽  
Vol 180 (3) ◽  
pp. 841-850 ◽  
Author(s):  
R A Pereira ◽  
D C Tscharke ◽  
A Simmons
Keyword(s):  
Gene Expression ◽  
Major Histocompatibility Complex ◽  
Schwann Cells ◽  
Sensory Neurons ◽  
Neural Tissue ◽  
Class I ◽  
Primary Sensory Neurons ◽  
Histocompatibility Complex ◽  
Simplex Virus

Major histocompatibility complex (MHC) deficiency is typical of almost all resident cells in normal neural tissue. However, CD8+ T cells, which recognize antigenic peptides in the context of class I MHC molecules, are known to mediate clearance of herpes simplex virus (HSV) from spinal ganglia of experimentally infected mice, leading to the hypothesis that class I expression in the peripheral nervous system must be upregulated in response to HSV infection. In addressing this hypothesis it is shown, in BALB/c (H-2d) mice, that normally deficient class I transcripts transiently accumulate in peripheral nerve Schwann cells, ganglionic satellite cells, and primary sensory neurons, indicating that in each of these cell types class I expression is regulated at the transcriptional level in vivo. Furthermore, for 3-4 wk after infection, H-2Kd/Dd antigens are expressed by satellite and Schwann cells but not neurons, suggesting additional posttranscriptional regulation of class I synthesis in neurons. Alternatively, the class I RNAs induced in neurons may not be derived from classical class I genes. Factors regulating H-2 class I expression emanate from within infected ganglia, probably from infected neurons themselves. However, induction of class I molecules was not maintained during latency, when viral gene expression in neurons is restricted to a single region within the virus repeats. These data have implications for the long-term survival of cells in HSV-infected neural tissue.

scholarly journals FOXA3, a Negative Regulator of Nur77 Expression and Activity in Testicular Steroidogenesis

2021 ◽  
Vol 2021 ◽  
pp. 1-8
Author(s):  
Hansle Kim ◽  
Sudeep Kumar ◽  
Keesook Lee
Keyword(s):  
Leydig Cells ◽  
Adenosine Monophosphate ◽  
Negative Regulator ◽  
Fine Tuning ◽  
Camp Signaling ◽  
Orphan Nuclear Receptor ◽  
Repressive Effect ◽  
Testicular Steroidogenesis ◽  
Steroidogenic Genes

Biosynthesis of testosterone occurs mainly in the testicular Leydig cells. Nur77, an orphan nuclear receptor that is expressed in response to the luteinizing hormone/cyclic adenosine monophosphate (LH/cAMP) signaling pathway, is one of the key factors that regulate steroidogenesis in Leydig cells. The function of Nur77 is modulated through interaction with other proteins. FOXA3, a transcription factor that is crucial for male fertility, is also expressed in Leydig cells. Here, we sought to elucidate the role of FOXA3 in testicular steroidogenesis by focusing on its interaction with Nur77. LH/cAMP signaling induces the onset of steroidogenesis in Leydig cells but has a repressive effect on the expression of FOXA3. Overexpression of FOXA3 in MA-10 Leydig cells repressed cAMP-induced expression of Nur77 and its target steroidogenic genes (StAR, P450c17, and Hsd3β). Furthermore, FOXA3 suppressed Nur77 transactivation of the promoter of steroidogenic genes. In mouse primary Leydig cells, adenovirus-mediated overexpression of FOXA3 had similar effects and resulted in decreased production of testosterone. Taken together, these results suggest the role of FOXA3 in the regulation of steroidogenic genes in Leydig cells and fine-tuning steroidogenesis in the testis.

scholarly journals HDAC inhibition reduces white matter injury after intracerebral hemorrhage

2020 ◽  
pp. 0271678X2094261
Author(s):  
Heng Yang ◽  
Wei Ni ◽  
Pengju Wei ◽  
Sicheng Li ◽  
Xinjie Gao ◽  
...  
Keyword(s):  
White Matter ◽  
Intracerebral Hemorrhage ◽  
Hdac Inhibitor ◽  
Histone Deacetylases ◽  
Macrophage Polarization ◽  
Conditional Knockout ◽  
White Matter Injury ◽  
Hdac Inhibition

Inhibition of histone deacetylases (HDACs) has been shown to reduce inflammation and white matter damage after various forms of brain injury via modulation of microglia/macrophage polarization. Previously we showed that the HDAC inhibitor scriptaid could attenuate white matter injury (WMI) after ICH. To access whether modulation of microglia/macrophage polarization might underlie this protection, we investigated the modulatory role of HDAC2 in microglia/macrophage polarization in response to WMI induced by intracerebral hemorrhage (ICH) and in primary microglia and oligodendrocyte co-cultures. HDAC2 activity was inhibited via conditional knockout of the Hdac2 gene in microglia or via administration of scriptaid. Conditional knockout of the Hdac2 gene in microglia and HDAC inhibition with scriptaid both improved neurological functional recovery and reduced WMI after ICH. Additionally, HDAC inhibition shifted microglia/macrophage polarization toward the M2 phenotype and reduced proinflammatory cytokine secretion after ICH in vivo. In vitro, a transwell co-culture model of microglia and oligodendrocytes also demonstrated that the HDAC inhibitor protected oligodendrocytes by modulating microglia polarization and mitigating neuroinflammation. Moreover, we found that scriptaid decreased the expression of pJAK2 and pSTAT1 in cultured microglia when stimulated with hemoglobin. Thus, HDAC inhibition ameliorated ICH-mediated neuroinflammation and WMI by modulating microglia/macrophage polarization.

The application of radiotherapy to the pediatric preclinical testing program: Results of a pilot study.

2012 ◽  
Vol 30 (15_suppl) ◽  
pp. 9544-9544
Author(s):  
Christopher E. Pelloski ◽  
Rita Kaplon ◽  
Mersiha Hadziahmetovic ◽  
Kathryn Bondra ◽  
Lanchun Lu ◽  
...  
Keyword(s):  
Gene Expression ◽  
Pilot Study ◽  
Kinase Inhibitor ◽  
Conditional Knockout ◽  
In Vivo Model ◽  
Cure Rate ◽  
Preclinical Testing ◽  
Testing Program ◽  
Pathway Gene

9544 Background: The Pediatric Preclinical Testing Program (PPTP) has been successfully utilized to determine the efficacy of novel agents by testing via its mouse-flank in vivo model. We report on the feasibility and biologic outcomes of a pilot study using rhabdomyosarcoma (RMS) xenograft lines treated with radiotherapy (RT) alone and concurrently with the mTOR tyrosine kinase inhibitor, AZD8055, using the PPTP model. Methods: We developed a mouse flank irradiation device for daily delivery of RT in clinically relevant doses (2 Gy per fraction up to 40 Gy).Two RMS xenograft lines of the PPTP, Rh30 (alveolar) and Rh18 (embryonal), were implanted into SCID mice, grown to appropriate volumes and were subjected to fractionated RT. In a second study, daily co-administration of AZD8055 (5-20 mg/Kg, gavage) with RT was performed. Cure rates (durable complete response >12 weeks post-treatment) and RT dose densities (given dose / initial xenograft volume, Gy/cc) were compared between groups. Results: With RT alone at mean dose-densities of 59-60 Gy/cc, cure was achieved in only 4/18 (22%) of the Rh30-bearing mice and 9/12 (75%) of the Rh18-bearing mice (p=0.006). Profiling data revealed higher levels of Fanconi anemia pathway gene expression in Rh30 compared to the more sensitive Rh18. Since recent data showed conditional knockout of mTOR resulted in the loss of FANCD2 gene expression, we postulated that blockade of TORC1/TORC2 with AZD8055 would reduce FANCD2 and increase the RT-sensitivity of Rh30. The addition of AZD8055 to RT resulted in a selective sensitization of the Rh30 line. With a mean RT dose-density of 27 Gy/cc, the cure rate in Rh30-bearing mice improved to 11/15 (73%). For the Rh18 group, the cure rate was 7/15 (46%) at a mean dose density of 44 Gy/cc. Western blot analysis showed the co-administration of AZD8055 abrogated the brisk increase in mTOR signaling and FANCD2 expression after the first several 2 Gy fractions of RT; most strikingly in Rh30. Conclusions: This study demonstrates the feasibility of applying RT to the PPTP model. It recapitulated the expected clinical radiobiology and demonstrated its utility in preclinical testing and the discovery of novel mechanisms of RT resistance in pediatric tumors.

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