1
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Derre A, Soler N, Billoux V, Benizri S, Vialet B, Rivat C, Barthélémy P, Carroll P, Pattyn A, Venteo S. FXYD2 antisense oligonucleotide provides an efficient approach for long-lasting relief of chronic peripheral pain. JCI Insight 2023; 8:161246. [PMID: 37154155 DOI: 10.1172/jci.insight.161246] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2022] [Accepted: 03/22/2023] [Indexed: 05/10/2023] Open
Abstract
Chronic pain, whether of inflammatory or neuropathic origin, affects about 18% of the population of developed countries, and most current treatments are only moderately effective and/or cause serious side effects. Therefore, the development of novel therapeutic approaches still represents a major challenge. The Na,K-ATPase modulator FXYD2 is critically required for the maintenance of neuropathic pain in rodents. Here, we set up a therapeutic protocol based on the use of chemically modified antisense oligonucleotides (ASOs) to inhibit FXYD2 expression and treat chronic pain. We identified an ASO targeting a 20-nucleotide stretch in the FXYD2 mRNA that is evolutionarily conserved between rats and humans and is a potent inhibitor of FXYD2 expression. We used this sequence to synthesize lipid-modified forms of ASO (FXYD2-LASO) to facilitate their entry into dorsal root ganglia neurons. We established that intrathecal or intravenous injections of FXYD2-LASO in rat models of neuropathic or inflammatory pain led to a virtually complete alleviation of their pain symptoms, without causing obvious side effects. Remarkably, by using 2'-O-2-methoxyethyl chemical stabilization of the ASO (FXYD2-LASO-Gapmer), we could significantly prolong the therapeutic action of a single treatment up to 10 days. This study establishes FXYD2-LASO-Gapmer administration as a promising and efficient therapeutic strategy for long-lasting relief of chronic pain conditions in human patients.
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Affiliation(s)
- Alexandre Derre
- Institute for Neurosciences of Montpellier, University of Montpellier, INSERM, Montpellier, France
| | - Noelian Soler
- Institute for Neurosciences of Montpellier, University of Montpellier, INSERM, Montpellier, France
| | - Valentine Billoux
- Institute for Neurosciences of Montpellier, University of Montpellier, INSERM, Montpellier, France
| | - Sebastien Benizri
- ARNA Laboratory, University of Bordeaux, INSERM U1212, UMR CNRS 5320, Bordeaux, France
| | - Brune Vialet
- ARNA Laboratory, University of Bordeaux, INSERM U1212, UMR CNRS 5320, Bordeaux, France
| | - Cyril Rivat
- Institute for Neurosciences of Montpellier, University of Montpellier, INSERM, Montpellier, France
| | - Philippe Barthélémy
- ARNA Laboratory, University of Bordeaux, INSERM U1212, UMR CNRS 5320, Bordeaux, France
| | - Patrick Carroll
- Institute for Neurosciences of Montpellier, University of Montpellier, INSERM, Montpellier, France
| | - Alexandre Pattyn
- Institute for Neurosciences of Montpellier, University of Montpellier, INSERM, Montpellier, France
| | - Stephanie Venteo
- Institute for Neurosciences of Montpellier, University of Montpellier, INSERM, Montpellier, France
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2
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Tassou A, Thouaye M, Gilabert D, Jouvenel A, Leyris JP, Sonrier C, Diouloufet L, Mechaly I, Mallié S, Bertin J, Chentouf M, Neiveyans M, Pugnière M, Martineau P, Robert B, Capdevila X, Valmier J, Rivat C. Activation of neuronal FLT3 promotes exaggerated sensorial and emotional pain-related behaviors facilitating the transition from acute to chronic pain. Prog Neurobiol 2023; 222:102405. [PMID: 36646299 DOI: 10.1016/j.pneurobio.2023.102405] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2022] [Revised: 12/16/2022] [Accepted: 01/12/2023] [Indexed: 01/15/2023]
Abstract
Acute pain has been associated with persistent pain sensitization of nociceptive pathways increasing the risk of transition from acute to chronic pain. We demonstrated the critical role of the FLT3- tyrosine kinase receptor, expressed in sensory neurons, in pain chronification after peripheral nerve injury. However, it is unclear whether injury-induced pain sensitization can also promote long-term mood disorders. Here, we evaluated the emotional and sensorial components of pain after a single (SI) or double paw incision (DI) and the implication of FLT3. DI mice showed an anxiodepressive-like phenotype associated with extended mechanical pain hypersensitivity and spontaneous pain when compared to SI mice. Behavioral exaggeration was associated with peripheral and spinal changes including increased microglia activation after DI versus SI. Intrathecal microglial inhibitors not only eliminated the exaggerated pain hypersensitivity produced by DI but also prevented anxiodepressive-related behaviors. Behavioral and cellular changes produced by DI were blocked in Flt3 knock-out animals and recapitulated by repeated intrathecal FL injections in naive animals. Finally, humanized antibodies against FLT3 reduced DI-induced behavioral and microglia changes. Altogether our results show that the repetition of peripheral lesions facilitate not only exaggerated nociceptive behaviors but also induced anxiodepressive disorders supported by spinal central changes that can be blocked by targeting peripheral FLT3.
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Affiliation(s)
- Adrien Tassou
- Univ Montpellier, Montpellier, France; Inserm U-1298, Institut des Neurosciences de Montpellier, Montpellier, France
| | - Maxime Thouaye
- Univ Montpellier, Montpellier, France; Inserm U-1298, Institut des Neurosciences de Montpellier, Montpellier, France
| | - Damien Gilabert
- Univ Montpellier, Montpellier, France; CNRS UMR 5203, Institut de Génomique Fonctionnelle, Montpellier, France
| | - Antoine Jouvenel
- Univ Montpellier, Montpellier, France; Inserm U-1298, Institut des Neurosciences de Montpellier, Montpellier, France
| | - Jean-Philippe Leyris
- Univ Montpellier, Montpellier, France; Inserm U-1298, Institut des Neurosciences de Montpellier, Montpellier, France; BIODOL Therapeutics, Cap Alpha, Clapiers, France
| | - Corinne Sonrier
- Univ Montpellier, Montpellier, France; Inserm U-1298, Institut des Neurosciences de Montpellier, Montpellier, France; BIODOL Therapeutics, Cap Alpha, Clapiers, France
| | - Lucie Diouloufet
- Univ Montpellier, Montpellier, France; Inserm U-1298, Institut des Neurosciences de Montpellier, Montpellier, France; BIODOL Therapeutics, Cap Alpha, Clapiers, France
| | - Ilana Mechaly
- Univ Montpellier, Montpellier, France; Inserm U-1298, Institut des Neurosciences de Montpellier, Montpellier, France
| | - Sylvie Mallié
- Univ Montpellier, Montpellier, France; Inserm U-1298, Institut des Neurosciences de Montpellier, Montpellier, France
| | - Juliette Bertin
- Univ Montpellier, Montpellier, France; Inserm U-1298, Institut des Neurosciences de Montpellier, Montpellier, France; BIODOL Therapeutics, Cap Alpha, Clapiers, France
| | - Myriam Chentouf
- Univ Montpellier, Montpellier, France; IRCM, INSERM U1194, ICM, Montpellier F-34298, France
| | - Madeline Neiveyans
- Univ Montpellier, Montpellier, France; IRCM, INSERM U1194, ICM, Montpellier F-34298, France
| | - Martine Pugnière
- Univ Montpellier, Montpellier, France; IRCM, INSERM U1194, ICM, Montpellier F-34298, France
| | - Pierre Martineau
- Univ Montpellier, Montpellier, France; IRCM, INSERM U1194, ICM, Montpellier F-34298, France
| | - Bruno Robert
- Univ Montpellier, Montpellier, France; IRCM, INSERM U1194, ICM, Montpellier F-34298, France
| | - Xavier Capdevila
- Univ Montpellier, Montpellier, France; Inserm U-1298, Institut des Neurosciences de Montpellier, Montpellier, France; Département d'anesthésiologie, Hôpital Universitaire Lapeyronie, Montpellier, France
| | - Jean Valmier
- Univ Montpellier, Montpellier, France; Inserm U-1298, Institut des Neurosciences de Montpellier, Montpellier, France
| | - Cyril Rivat
- Univ Montpellier, Montpellier, France; Inserm U-1298, Institut des Neurosciences de Montpellier, Montpellier, France.
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3
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Zhang P, Perez OC, Southey BR, Sweedler JV, Pradhan AA, Rodriguez-Zas SL. Alternative Splicing Mechanisms Underlying Opioid-Induced Hyperalgesia. Genes (Basel) 2021; 12:1570. [PMID: 34680965 PMCID: PMC8535871 DOI: 10.3390/genes12101570] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2021] [Revised: 09/19/2021] [Accepted: 09/30/2021] [Indexed: 12/13/2022] Open
Abstract
Prolonged use of opioids can cause opioid-induced hyperalgesia (OIH). The impact of alternative splicing on OIH remains partially characterized. A study of the absolute and relative modes of action of alternative splicing further the understanding of the molecular mechanisms underlying OIH. Differential absolute and relative isoform profiles were detected in the trigeminal ganglia and nucleus accumbens of mice presenting OIH behaviors elicited by chronic morphine administration relative to control mice. Genes that participate in glutamatergic synapse (e.g., Grip1, Grin1, Wnk3), myelin protein processes (e.g., Mbp, Mpz), and axon guidance presented absolute and relative splicing associated with OIH. Splicing of genes in the gonadotropin-releasing hormone receptor pathway was detected in the nucleus accumbens while splicing in the vascular endothelial growth factor, endogenous cannabinoid signaling, circadian clock system, and metabotropic glutamate receptor pathways was detected in the trigeminal ganglia. A notable finding was the prevalence of alternatively spliced transcription factors and regulators (e.g., Ciart, Ablim2, Pbx1, Arntl2) in the trigeminal ganglia. Insights into the nociceptive and antinociceptive modulatory action of Hnrnpk were gained. The results from our study highlight the impact of alternative splicing and transcriptional regulators on OIH and expose the need for isoform-level research to advance the understanding of morphine-associated hyperalgesia.
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Affiliation(s)
- Pan Zhang
- Illinois Informatics Institute, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA;
| | - Olivia C. Perez
- Department of Animal Sciences, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA; (O.C.P.); (B.R.S.)
| | - Bruce R. Southey
- Department of Animal Sciences, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA; (O.C.P.); (B.R.S.)
| | - Jonathan V. Sweedler
- Department of Chemistry and the Beckman Institute, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA;
| | - Amynah A. Pradhan
- Department of Psychiatry, University of Illinois at Chicago, Chicago, IL 60612, USA;
| | - Sandra L. Rodriguez-Zas
- Illinois Informatics Institute, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA;
- Department of Animal Sciences, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA; (O.C.P.); (B.R.S.)
- Department of Statistics, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
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4
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Virtuoso A, Herrera-Rincon C, Papa M, Panetsos F. Dependence of Neuroprosthetic Stimulation on the Sensory Modality of the Trigeminal Neurons Following Nerve Injury. Implications in the Design of Future Sensory Neuroprostheses for Correct Perception and Modulation of Neuropathic Pain. Front Neurosci 2019; 13:389. [PMID: 31118880 PMCID: PMC6504809 DOI: 10.3389/fnins.2019.00389] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2018] [Accepted: 04/04/2019] [Indexed: 12/02/2022] Open
Abstract
Amputation of a sensory peripheral nerve induces severe anatomical and functional changes along the afferent pathway as well as perception alterations and neuropathic pain. In previous studies we showed that electrical stimulation applied to a transected infraorbital nerve protects the somatosensory cortex from the above-mentioned sensory deprivation-related changes. In the present study we focus on the initial tract of the somatosensory pathway and we investigate the way weak electrical stimulation modulates the neuroprotective-neuroregenerative and functional processes of trigeminal ganglia primary sensory neurons by studying the expression of neurotrophins (NTFs) and Glia-Derived Neurotrophic Factors (GDNFs) receptors. Neurostimulation was applied to the proximal stump of a transected left infraorbitary nerve using a neuroprosthetic micro-device 12 h/day for 4 weeks in freely behaving rats. Neurons were studied by in situ hybridization and immunohistochemistry against RET (proto-oncogene tyrosine kinase "rearranged during transfection"), tropomyosin-related kinases (TrkA, TrkB, TrkC) receptors and IB4 (Isolectin B4 from Griffonia simplicifolia). Intra-group (left vs. right ganglia) and inter-group comparisons (between Control, Axotomization and Stimulation-after-axotomization groups) were performed using the mean percentage change of the number of positive cells per section [100∗(left-right)/right)]. Intra-group differences were studied by paired t-tests. For inter-group comparisons ANOVA test followed by post hoc LSD test (when P < 0.05) were used. Significance level (α) was set to 0.05 in all cases. Results showed that (i) neurostimulation has heterogeneous effects on primary nociceptive and mechanoceptive/proprioceptive neurons; (ii) neurostimulation affects RET-expressing small and large neurons which include thermo-nociceptors and mechanoceptors, as well as on the IB4- and TrkB-positive populations, which mainly correspond to non-peptidergic thermo-nociceptive cells and mechanoceptors respectively. Our results suggest (i) electrical stimulation differentially affects modality-specific primary sensory neurons (ii) artificial input mainly acts on specific nociceptive and mechanoceptive neurons (iii) neuroprosthetic stimulation could be used to modulate peripheral nerve injuries-induced neuropathic pain. These could have important functional implications in both, the design of effective clinical neurostimulation-based protocols and the development of neuroprosthetic devices, controlling primary sensory neurons through selective neurostimulation.
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Affiliation(s)
- Assunta Virtuoso
- Division of Human Anatomy – Neuronal Networks Morphology Lab, Department of Mental, Physical Health and Preventive Medicine, University of Campania “Luigi Vanvitelli”, Naples, Italy
| | - Celia Herrera-Rincon
- Neuro-computing & Neuro-robotics Research Group, Universidad Complutense de Madrid, Madrid, Spain
- Instituto de Investigación Sanitaria San Carlos, Hospital San Carlos de Madrid (IdISSC), Madrid, Spain
| | - Michele Papa
- Division of Human Anatomy – Neuronal Networks Morphology Lab, Department of Mental, Physical Health and Preventive Medicine, University of Campania “Luigi Vanvitelli”, Naples, Italy
| | - Fivos Panetsos
- Neuro-computing & Neuro-robotics Research Group, Universidad Complutense de Madrid, Madrid, Spain
- Instituto de Investigación Sanitaria San Carlos, Hospital San Carlos de Madrid (IdISSC), Madrid, Spain
- Silk Biomed, Madrid, Spain
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5
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Ohayon D, Escalas N, Cochard P, Glise B, Danesin C, Soula C. Sulfatase 2 promotes generation of a spinal cord astrocyte subtype that stands out through the expression of Olig2. Glia 2019; 67:1478-1495. [PMID: 30980466 PMCID: PMC6617735 DOI: 10.1002/glia.23621] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2018] [Revised: 03/25/2019] [Accepted: 03/29/2019] [Indexed: 12/12/2022]
Abstract
Generation of glial cell diversity in the developing spinal cord is known to depend on spatio-temporal patterning programs. In particular, expression of the transcription factor Olig2 in neural progenitors of the pMN domain is recognized as critical to their fate choice decision to form oligodendrocyte precursor cells (OPCs) instead of astrocyte precursors (APs). However, generating some confusion, lineage-tracing studies of Olig2 progenitors in the spinal cord provided evidence that these progenitors also generate some astrocytes. Here, we addressed the role of the heparan sulfate-editing enzyme Sulf2 in the control of gliogenesis and found an unanticipated function for this enzyme. At initiation of gliogenesis in mouse, Sulf2 is expressed in ventral neural progenitors of the embryonic spinal cord, including in Olig2-expressing cells of the pMN domain. We found that sulf2 deletion, while not affecting OPC production, impairs generation of a previously unknown Olig2-expressing pMN-derived cell subtype that, in contrast to OPCs, does not upregulate Sox10, PDGFRα or Olig1. Instead, these cells activate expression of AP identity genes, including aldh1L1 and fgfr3 and, of note, retain Olig2 expression as they populate the spinal parenchyma at embryonic stages but also as they differentiate into mature astrocytes at postnatal stages. Thus, our study, by revealing the existence of Olig2-expressing APs that segregate early from pMN cells under the influence of Sulf2, supports the existence of a common source of APs and OPCs in the ventral spinal cord and highlights divergent regulatory mechanism for the development of pMN-derived OPCs and APs.
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Affiliation(s)
- David Ohayon
- Centre de Biologie du Développement (CBD) CNRS/UPS, Centre de Biologie Intégrative (CBI), Université de Toulouse, Toulouse, France
| | - Nathalie Escalas
- Centre de Biologie du Développement (CBD) CNRS/UPS, Centre de Biologie Intégrative (CBI), Université de Toulouse, Toulouse, France
| | - Philippe Cochard
- Centre de Biologie du Développement (CBD) CNRS/UPS, Centre de Biologie Intégrative (CBI), Université de Toulouse, Toulouse, France
| | - Bruno Glise
- Centre de Biologie du Développement (CBD) CNRS/UPS, Centre de Biologie Intégrative (CBI), Université de Toulouse, Toulouse, France
| | - Cathy Danesin
- Centre de Biologie du Développement (CBD) CNRS/UPS, Centre de Biologie Intégrative (CBI), Université de Toulouse, Toulouse, France
| | - Cathy Soula
- Centre de Biologie du Développement (CBD) CNRS/UPS, Centre de Biologie Intégrative (CBI), Université de Toulouse, Toulouse, France
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6
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Ohayon D, Garcès A, Joly W, Soukkarieh C, Takagi T, Sabourin JC, Agius E, Darling DS, De Santa Barbara P, Higashi Y, Stolt CC, Hugnot JP, Richardson WD, Carroll P, Pattyn A. Onset of Spinal Cord Astrocyte Precursor Emigration from the Ventricular Zone Involves the Zeb1 Transcription Factor. Cell Rep 2017; 17:1473-1481. [PMID: 27806288 DOI: 10.1016/j.celrep.2016.10.016] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2016] [Revised: 06/17/2016] [Accepted: 10/04/2016] [Indexed: 01/01/2023] Open
Abstract
During spinal cord development, astrocyte precursors arise from neuroepithelial progenitors, delaminate from the ventricular zone, and migrate toward their final locations where they differentiate. Although the mechanisms underlying their early specification and late differentiation are being deciphered, less is known about the temporal control of their migration. Here, we show that the epithelial-mesenchymal transition regulator Zeb1 is expressed in glial precursors and report that loss of Zeb1 function specifically delays the onset of astrocyte precursor delamination from the ventricular zone, correlating with transient deregulation of the adhesion protein Cadherin-1. Consequently, astrocyte precursor invasion into the Zeb1-/- mutant white matter is delayed, and induction of their differentiation is postponed. These findings illustrate how fine regulation of adhesive properties influences the onset of neural precursor migration and further support the notion that duration of exposure of migrating astrocyte precursors to environmental cues and/or their correct positioning influence the timing of their differentiation.
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Affiliation(s)
- David Ohayon
- INSERM U1051, Institut des Neurosciences de Montpellier, 34091 Montpellier, France; Université de Toulouse, Centre National de la Recherche Scientifique (CNRS), CBD-UMR5547, 31062 Toulouse, France; Wolfson Institute for Biomedical Research, University College London, London WC1E 6BT, UK
| | - Alain Garcès
- INSERM U1051, Institut des Neurosciences de Montpellier, 34091 Montpellier, France
| | - Willy Joly
- INSERM U1051, Institut des Neurosciences de Montpellier, 34091 Montpellier, France
| | - Chadi Soukkarieh
- INSERM U1051, Institut des Neurosciences de Montpellier, 34091 Montpellier, France; Department of Animal Biology, Faculty of Sciences, Damascus University, Damascus, Syria
| | - Tsuyoshi Takagi
- Department of Perinatology, Institute for Developmental Research, Aichi Human Service Center, Kasugai, Aichi 480-0392, Japan
| | | | - Eric Agius
- Université de Toulouse, Centre National de la Recherche Scientifique (CNRS), CBD-UMR5547, 31062 Toulouse, France
| | - Douglas S Darling
- Department of Oral Immunology and Infectious Diseases, University of Louisville, Louisville, KY 40202, USA
| | - Pascal De Santa Barbara
- PhyMedExp, INSERM U1046, CNRS UMR 9214, University of Montpellier, 34295 Montpellier, France
| | - Yujiro Higashi
- Department of Perinatology, Institute for Developmental Research, Aichi Human Service Center, Kasugai, Aichi 480-0392, Japan
| | - Claus C Stolt
- Institut für Biochemie, Emil-Fischer-Zentrum, Universität Erlangen-Nürnberg, 91054 Erlangen, Germany
| | - Jean-Philippe Hugnot
- INSERM U1051, Institut des Neurosciences de Montpellier, 34091 Montpellier, France
| | - William D Richardson
- Wolfson Institute for Biomedical Research, University College London, London WC1E 6BT, UK
| | - Patrick Carroll
- INSERM U1051, Institut des Neurosciences de Montpellier, 34091 Montpellier, France
| | - Alexandre Pattyn
- INSERM U1051, Institut des Neurosciences de Montpellier, 34091 Montpellier, France.
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7
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Yagi S, Shiojiri N. Identification of novel genetic markers for mouse yolk sac cells by using microarray analyses. Placenta 2017; 49:68-71. [DOI: 10.1016/j.placenta.2016.11.013] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/27/2016] [Revised: 11/07/2016] [Accepted: 11/22/2016] [Indexed: 11/26/2022]
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8
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Ventéo S, Laffray S, Wetzel C, Rivat C, Scamps F, Méchaly I, Bauchet L, Raoul C, Bourinet E, Lewin GR, Carroll P, Pattyn A. Fxyd2 regulates Aδ- and C-fiber mechanosensitivity and is required for the maintenance of neuropathic pain. Sci Rep 2016; 6:36407. [PMID: 27805035 PMCID: PMC5090990 DOI: 10.1038/srep36407] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2016] [Accepted: 10/12/2016] [Indexed: 01/24/2023] Open
Abstract
Identification of the molecular mechanisms governing sensory neuron subtype excitability is a key requisite for the development of treatments for somatic sensory disorders. Here, we show that the Na,K-ATPase modulator Fxyd2 is specifically required for setting the mechanosensitivity of Aδ-fiber low-threshold mechanoreceptors and sub-populations of C-fiber nociceptors, a role consistent with its restricted expression profile in the spinal somatosensory system. We also establish using the spared nerve injury model of neuropathic pain, that loss of Fxyd2 function, either constitutively in Fxyd2−/− mice or acutely in neuropathic rats, efficiently alleviates mechanical hypersensitivity induced by peripheral nerve lesions. The role of Fxyd2 in modulating Aδ- and C-fibers mechanosensitivity likely accounts for the anti-allodynic effect of Fxyd2 knockdown. Finally, we uncover the evolutionarily conserved restricted expression pattern of FXYD2 in human dorsal root ganglia, thus identifying this molecule as a potentially promising therapeutic target for peripheral neuropathic pain management.
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Affiliation(s)
- Stéphanie Ventéo
- INSERM U1051, Institut des Neurosciences de Montpellier, Hôpital St Eloi, 80 rue Augustin Fliche, 34091 Montpellier, France
| | - Sophie Laffray
- UMR5203, INSERM U1191, Institut de Génomique Fonctionnelle, 141 rue de la Cardonille, 34094 Montpellier, France.,Université de Montpellier, Place Eugène Bataillon, 34090 Montpellier, France
| | - Christiane Wetzel
- Department of Neuroscience, Max-Delbrück Center for Molecular Medicine, Robert-Rössle Str. 10, D-13125 Berlin, Germany
| | - Cyril Rivat
- INSERM U1051, Institut des Neurosciences de Montpellier, Hôpital St Eloi, 80 rue Augustin Fliche, 34091 Montpellier, France.,Université de Montpellier, Place Eugène Bataillon, 34090 Montpellier, France
| | - Frédérique Scamps
- INSERM U1051, Institut des Neurosciences de Montpellier, Hôpital St Eloi, 80 rue Augustin Fliche, 34091 Montpellier, France
| | - Ilana Méchaly
- INSERM U1051, Institut des Neurosciences de Montpellier, Hôpital St Eloi, 80 rue Augustin Fliche, 34091 Montpellier, France.,Université de Montpellier, Place Eugène Bataillon, 34090 Montpellier, France
| | - Luc Bauchet
- INSERM U1051, Institut des Neurosciences de Montpellier, Hôpital St Eloi, 80 rue Augustin Fliche, 34091 Montpellier, France.,Département de Neurochirurgie, Hôpital Gui de Chauliac, CHU, 80 avenue Augustin Fliche, 34295 Montpellier, France
| | - Cédric Raoul
- INSERM U1051, Institut des Neurosciences de Montpellier, Hôpital St Eloi, 80 rue Augustin Fliche, 34091 Montpellier, France
| | - Emmanuel Bourinet
- UMR5203, INSERM U1191, Institut de Génomique Fonctionnelle, 141 rue de la Cardonille, 34094 Montpellier, France
| | - Gary R Lewin
- Department of Neuroscience, Max-Delbrück Center for Molecular Medicine, Robert-Rössle Str. 10, D-13125 Berlin, Germany
| | - Patrick Carroll
- INSERM U1051, Institut des Neurosciences de Montpellier, Hôpital St Eloi, 80 rue Augustin Fliche, 34091 Montpellier, France
| | - Alexandre Pattyn
- INSERM U1051, Institut des Neurosciences de Montpellier, Hôpital St Eloi, 80 rue Augustin Fliche, 34091 Montpellier, France
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9
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Patent highlights: December 2015-January 2016. Pharm Pat Anal 2016; 5:147-53. [PMID: 27088860 DOI: 10.4155/ppa-2016-0009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
A snapshot of noteworthy recent developments in the patent literature of relevance to pharmaceutical and medical research and development.
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10
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Arystarkhova E. Beneficial Renal and Pancreatic Phenotypes in a Mouse Deficient in FXYD2 Regulatory Subunit of Na,K-ATPase. Front Physiol 2016; 7:88. [PMID: 27014088 PMCID: PMC4779850 DOI: 10.3389/fphys.2016.00088] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2015] [Accepted: 02/22/2016] [Indexed: 11/25/2022] Open
Abstract
The fundamental role of Na,K-ATPase in eukaryotic cells calls for complex and efficient regulation of its activity. Besides alterations in gene expression and trafficking, kinetic properties of the pump are modulated by reversible association with single span membrane proteins, the FXYDs. Seven members of the family are expressed in a tissue-specific manner, affecting pump kinetics in all possible permutations. This mini-review focuses on functional properties of FXYD2 studied in transfected cells, and on noteworthy and unexpected phenotypes discovered in a Fxyd2−∕− mouse. FXYD2, the gamma subunit, reduces activity of Na,K-ATPase either by decreasing affinity for Na+, or reducing Vmax. FXYD2 mRNA splicing and editing provide another layer for regulation of Na,K-ATPase. In kidney of knockouts, there was elevated activity for Na,K-ATPase and for NCC and NKCC2 apical sodium transporters. That should lead to sodium retention and hypertension, however, the mice were in sodium balance and normotensive. Adult Fxyd2−∕− mice also exhibited a mild pancreatic phenotype with enhanced glucose tolerance, elevation of circulating insulin, but no insulin resistance. There was an increase in beta cell proliferation and beta cell mass that correlated with activation of the PI3K-Akt pathway. The Fxyd2−∕− mice are thus in a highly desirable state: the animals are resistant to Na+ retention, and showed improved glucose control, i.e., they display favorable metabolic adaptations to protect against development of salt-sensitive hypertension and diabetes. Investigation of the mechanisms of these adaptations in the mouse has the potential to unveil a novel therapeutic FXYD2-dependent strategy.
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Affiliation(s)
- Elena Arystarkhova
- Laboratory of Membrane Biology, Neurosurgery, Massachusetts General Hospital Boston, MA, USA
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Li CL, Li KC, Wu D, Chen Y, Luo H, Zhao JR, Wang SS, Sun MM, Lu YJ, Zhong YQ, Hu XY, Hou R, Zhou BB, Bao L, Xiao HS, Zhang X. Somatosensory neuron types identified by high-coverage single-cell RNA-sequencing and functional heterogeneity. Cell Res 2015; 26:83-102. [PMID: 26691752 DOI: 10.1038/cr.2015.149] [Citation(s) in RCA: 249] [Impact Index Per Article: 27.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2015] [Revised: 11/04/2015] [Accepted: 12/01/2015] [Indexed: 11/09/2022] Open
Abstract
Sensory neurons are distinguished by distinct signaling networks and receptive characteristics. Thus, sensory neuron types can be defined by linking transcriptome-based neuron typing with the sensory phenotypes. Here we classify somatosensory neurons of the mouse dorsal root ganglion (DRG) by high-coverage single-cell RNA-sequencing (10 950 ± 1 218 genes per neuron) and neuron size-based hierarchical clustering. Moreover, single DRG neurons responding to cutaneous stimuli are recorded using an in vivo whole-cell patch clamp technique and classified by neuron-type genetic markers. Small diameter DRG neurons are classified into one type of low-threshold mechanoreceptor and five types of mechanoheat nociceptors (MHNs). Each of the MHN types is further categorized into two subtypes. Large DRG neurons are categorized into four types, including neurexophilin 1-expressing MHNs and mechanical nociceptors (MNs) expressing BAI1-associated protein 2-like 1 (Baiap2l1). Mechanoreceptors expressing trafficking protein particle complex 3-like and Baiap2l1-marked MNs are subdivided into two subtypes each. These results provide a new system for cataloging somatosensory neurons and their transcriptome databases.
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Affiliation(s)
- Chang-Lin Li
- Institute of Neuroscience and State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 20031, China
| | - Kai-Cheng Li
- Institute of Neuroscience and State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 20031, China
| | - Dan Wu
- Institute of Neuroscience and State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 20031, China
| | - Yan Chen
- Institute of Neuroscience and State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 20031, China
| | - Hao Luo
- School of Life Science and Technology, ShanghaiTec University, Shanghai 200031, China
| | - Jing-Rong Zhao
- Institute of Neuroscience and State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 20031, China
| | - Sa-Shuang Wang
- School of Life Science and Technology, ShanghaiTec University, Shanghai 200031, China
| | - Ming-Ming Sun
- National Engineering Center for Biochip at Shanghai, Shanghai, China
| | - Ying-Jin Lu
- Institute of Neuroscience and State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 20031, China
| | - Yan-Qing Zhong
- Institute of Neuroscience and State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 20031, China
| | - Xu-Ye Hu
- Shanghai Clinical Center, Chinese Academy of Sciences/XuHui Central Hospital, Shanghai, China
| | - Rui Hou
- National Engineering Center for Biochip at Shanghai, Shanghai, China
| | - Bei-Bei Zhou
- National Engineering Center for Biochip at Shanghai, Shanghai, China
| | - Lan Bao
- State Key Laboratory of Cell Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences.,School of Life Science and Technology, ShanghaiTec University, Shanghai 200031, China
| | - Hua-Sheng Xiao
- National Engineering Center for Biochip at Shanghai, Shanghai, China
| | - Xu Zhang
- Institute of Neuroscience and State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 20031, China.,School of Life Science and Technology, ShanghaiTec University, Shanghai 200031, China
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Wang F, Cai B, Li KC, Hu XY, Lu YJ, Wang Q, Bao L, Zhang X. FXYD2, a γ subunit of Na⁺, K⁺-ATPase, maintains persistent mechanical allodynia induced by inflammation. Cell Res 2015; 25:318-34. [PMID: 25633594 DOI: 10.1038/cr.2015.12] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2014] [Revised: 10/09/2014] [Accepted: 12/15/2014] [Indexed: 01/08/2023] Open
Abstract
Na⁺, K⁺-ATPase (NKA) is required to generate the resting membrane potential in neurons. Nociceptive afferent neurons express not only the α and β subunits of NKA but also the γ subunit FXYD2. However, the neural function of FXYD2 is unknown. The present study shows that FXYD2 in nociceptive neurons is necessary for maintaining the mechanical allodynia induced by peripheral inflammation. FXYD2 interacted with α1NKA and negatively regulated the NKA activity, depolarizing the membrane potential of nociceptive neurons. Mechanical allodynia initiated in FXYD2-deficient mice was abolished 4 days after inflammation, whereas it persisted for at least 3 weeks in wild-type mice. Importantly, the FXYD2/α1NKA interaction gradually increased after inflammation and peaked on day 4 post inflammation, resulting in reduction of NKA activity, depolarization of neuron membrane and facilitation of excitatory afferent neurotransmission. Thus, the increased FXYD2 activity may be a fundamental mechanism underlying the persistent hypersensitivity to pain induced by inflammation.
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Affiliation(s)
- Feng Wang
- Institute of Neuroscience and State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Bing Cai
- Institute of Neuroscience and State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Kai-Cheng Li
- Institute of Neuroscience and State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Xu-Ye Hu
- Shanghai Clinical Center, Chinese Academy of Sciences/XuHui Central Hospital, Shanghai, China
| | - Ying-Jin Lu
- Institute of Neuroscience and State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Qiong Wang
- State Key Laboratory of Cell Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Lan Bao
- 1] State Key Laboratory of Cell Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China [2] School of Life Science and Technology, ShanghaiTech University, Shanghai 200031, China
| | - Xu Zhang
- 1] Institute of Neuroscience and State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China [2] School of Life Science and Technology, ShanghaiTech University, Shanghai 200031, China
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Elzière L, Sar C, Ventéo S, Bourane S, Puech S, Sonrier C, Boukhadaoui H, Fichard A, Pattyn A, Valmier J, Carroll P, Méchaly I. CaMKK-CaMK1a, a new post-traumatic signalling pathway induced in mouse somatosensory neurons. PLoS One 2014; 9:e97736. [PMID: 24840036 PMCID: PMC4026325 DOI: 10.1371/journal.pone.0097736] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2013] [Accepted: 04/24/2014] [Indexed: 11/19/2022] Open
Abstract
Neurons innervating peripheral tissues display complex responses to peripheral nerve injury. These include the activation and suppression of a variety of signalling pathways that together influence regenerative growth and result in more or less successful functional recovery. However, these responses can be offset by pathological consequences including neuropathic pain. Calcium signalling plays a major role in the different steps occurring after nerve damage. As part of our studies to unravel the roles of injury-induced molecular changes in dorsal root ganglia (DRG) neurons during their regeneration, we show that the calcium calmodulin kinase CaMK1a is markedly induced in mouse DRG neurons in several models of mechanical peripheral nerve injury, but not by inflammation. Intrathecal injection of NRTN or GDNF significantly prevents the post-traumatic induction of CaMK1a suggesting that interruption of target derived factors might be a starter signal in this de novo induction. Inhibition of CaMK signalling in injured DRG neurons by pharmacological means or treatment with CaMK1a siRNA resulted in decreased velocity of neurite growth in vitro. Altogether, the results suggest that CaMK1a induction is part of the intrinsic regenerative response of DRG neurons to peripheral nerve injury, and is thus a potential target for therapeutic intervention to improve peripheral nerve regeneration.
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Affiliation(s)
- Lucie Elzière
- Institute for Neurosciences of Montpellier, I.N.S.E.R.M. U1051, Montpellier, France
| | - Chamroeun Sar
- Institute for Neurosciences of Montpellier, I.N.S.E.R.M. U1051, Montpellier, France
| | - Stéphanie Ventéo
- Institute for Neurosciences of Montpellier, I.N.S.E.R.M. U1051, Montpellier, France
| | - Steeve Bourane
- Molecular Neurobiology Laboratory, The Salk Institute, La Jolla, California, United States of America
| | - Sylvie Puech
- Institute for Neurosciences of Montpellier, I.N.S.E.R.M. U1051, Montpellier, France
| | - Corinne Sonrier
- Institute for Neurosciences of Montpellier, I.N.S.E.R.M. U1051, Montpellier, France
| | - Hassan Boukhadaoui
- Institute for Neurosciences of Montpellier, I.N.S.E.R.M. U1051, Montpellier, France
| | - Agnès Fichard
- Institute for Neurosciences of Montpellier, I.N.S.E.R.M. U1051, Montpellier, France
- Department BioMV, University of Montpellier II, Montpellier, France
| | - Alexandre Pattyn
- Institute for Neurosciences of Montpellier, I.N.S.E.R.M. U1051, Montpellier, France
| | - Jean Valmier
- Institute for Neurosciences of Montpellier, I.N.S.E.R.M. U1051, Montpellier, France
- Department BioMV, University of Montpellier II, Montpellier, France
| | - Patrick Carroll
- Institute for Neurosciences of Montpellier, I.N.S.E.R.M. U1051, Montpellier, France
| | - Ilana Méchaly
- Institute for Neurosciences of Montpellier, I.N.S.E.R.M. U1051, Montpellier, France
- Department BioMV, University of Montpellier II, Montpellier, France
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Zhao H, Jin G, Cui K, Ren D, Liu T, Chen P, Wong S, Li F, Fan Y, Rodriguez A, Chang J, Wong STC. Novel modeling of cancer cell signaling pathways enables systematic drug repositioning for distinct breast cancer metastases. Cancer Res 2013; 73:6149-63. [PMID: 24097821 DOI: 10.1158/0008-5472.can-12-4617] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
A new type of signaling network element, called cancer signaling bridges (CSB), has been shown to have the potential for systematic and fast-tracked drug repositioning. On the basis of CSBs, we developed a computational model to derive specific downstream signaling pathways that reveal previously unknown target-disease connections and new mechanisms for specific cancer subtypes. The model enables us to reposition drugs based on available patient gene expression data. We applied this model to repurpose known or shelved drugs for brain, lung, and bone metastases of breast cancer with the hypothesis that cancer subtypes have their own specific signaling mechanisms. To test the hypothesis, we addressed specific CSBs for each metastasis that satisfy (i) CSB proteins are activated by the maximal number of enriched signaling pathways specific to a given metastasis, and (ii) CSB proteins are involved in the most differential expressed coding genes specific to each breast cancer metastasis. The identified signaling networks for the three types of breast cancer metastases contain 31, 15, and 18 proteins and are used to reposition 15, 9, and 2 drug candidates for the brain, lung, and bone metastases. We conducted both in vitro and in vivo preclinical experiments as well as analysis on patient tumor specimens to evaluate the targets and repositioned drugs. Of special note, we found that the Food and Drug Administration-approved drugs, sunitinib and dasatinib, prohibit brain metastases derived from breast cancer, addressing one particularly challenging aspect of this disease.
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Affiliation(s)
- Hong Zhao
- Authors' Affiliations: Department of Systems Medicine and Bioengineering; NCI Center for Modeling Cancer Development, The Methodist Hospital Research Institute, Weill Cornell Medical College; Methodist Cancer Center, The Methodist Hospital; Dan L. Duncan Cancer Center, Baylor College of Medicine, Houston; and The University of Texas at Austin, Austin, Texas
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Swarts DRA, Van Neste L, Henfling MER, Eijkenboom I, Eijk PP, van Velthuysen ML, Vink A, Volante M, Ylstra B, Van Criekinge W, van Engeland M, Ramaekers FCS, Speel EJM. An exploration of pathways involved in lung carcinoid progression using gene expression profiling. Carcinogenesis 2013; 34:2726-37. [PMID: 23929435 DOI: 10.1093/carcin/bgt271] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Pulmonary carcinoids comprise a well-differentiated subset of neuroendocrine tumors usually associated with a favorable prognosis, but mechanisms underlying disease progression are poorly understood. In an explorative approach to identify pathways associated with progression, we compared gene expression profiles of tumors from five patients with a favorable and five with a poor disease outcome. Differentially expressed genes were validated using quantitative real-time PCR on 65 carcinoid tumors, in combination with survival analysis. One of the identified pathways was further examined using immunohistochemistry. As compared with other chromosomal locations, a significantly higher number of genes downregulated in carcinoids with a poor prognosis were located at chromosome 11q (P = 0.00017), a region known to be frequently lost in carcinoids. In addition, a number of upregulated genes were found involved in the mitotic spindle checkpoint, the chromosomal passenger complex (CPC), mitotic kinase CDC2 activity and the BRCA-Fanconi anemia pathway. At the individual gene level, BIRC5 (survivin), BUB1, CD44, IL20RA, KLK12 and OTP were independent predictors of patient outcome. For survivin, the number of positive nuclei was also related to poor prognosis within the group of carcinoids. Aurora B kinase and survivin, major components of the CPC, were particularly upregulated in high-grade carcinomas and may therefore comprise therapeutic targets for these tumors. To our knowledge, this is the first expression profiling study focusing specifically on pulmonary carcinoids and progression. We have identified novel pathways underlying malignant progression and validated several genes as being strong prognostic indicators, some of which could serve as putative therapeutic targets.
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Affiliation(s)
- Dorian R A Swarts
- Department of Molecular Cell Biology, GROW - School for Oncology & Developmental Biology, Maastricht University Medical Center, PO Box 616, 6200 MD Maastricht, The Netherlands
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Arystarkhova E, Liu YB, Salazar C, Stanojevic V, Clifford RJ, Kaplan JH, Kidder GM, Sweadner KJ. Hyperplasia of pancreatic beta cells and improved glucose tolerance in mice deficient in the FXYD2 subunit of Na,K-ATPase. J Biol Chem 2013; 288:7077-85. [PMID: 23344951 DOI: 10.1074/jbc.m112.401190] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Restoration of the functional potency of pancreatic islets either through enhanced proliferation (hyperplasia) or increase in size (hypertrophy) of beta cells is a major objective for intervention in diabetes. We have obtained experimental evidence that global knock-out of a small, single-span regulatory subunit of Na,K-ATPase, FXYD2, alters glucose control. Adult Fxyd2(-/-) mice showed significantly lower blood glucose levels, no signs of peripheral insulin resistance, and improved glucose tolerance compared with their littermate controls. Strikingly, there was a substantial hyperplasia in pancreatic beta cells from the Fxyd2(-/-) mice compared with the wild type littermates, compatible with an observed increase in the level of circulating insulin. No changes were seen in the exocrine compartment of the pancreas, and the mice had only a mild, well-adapted renal phenotype. Morphometric analysis revealed an increase in beta cell mass in KO compared with WT mice. This appears to explain a phenotype of hyperinsulinemia. By RT-PCR, Western blot, and immunocytochemistry we showed the FXYD2b splice variant in pancreatic beta cells from wild type mice. Phosphorylation of Akt kinase was significantly higher under basal conditions in freshly isolated islets from Fxyd2(-/-) mice compared with their WT littermates. Inducible expression of FXYD2 in INS 832/13 cells produced a reduction in the phosphorylation level of Akt, and phosphorylation was restored in parallel with degradation of FXYD2. Thus we suggest that in pancreatic beta cells FXYD2 plays a role in Akt signaling pathways associated with cell growth and proliferation.
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Affiliation(s)
- Elena Arystarkhova
- Laboratory Membrane Biology, Massachusetts General Hospital, Boston, Massachusetts 2114, USA.
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