The Lengthening of a Giant Protein: When, How, and Why?

Abstract Subcommissural organ (SCO)-spondin is a giant glycoprotein of more than 5000 amino acids found in Vertebrata, expressed in the central nervous system and constitutive of Reissner's fiber. For the first time, in situ hybridization performed on zebrafish (Danio rerio) embryos shows that the gene encoding this protein is expressed transitionally in the floor plate, the ventral midline of the neural tube, and later in the diencephalic third ventricle roof, the SCO. The modular organization of the protein in Echinodermata (Strongylocentrotus purpuratus), Urochordata (Ciona savignyi and C. intestinalis), and Vertebrata (Teleostei, Amphibia, Aves and Mammalia) is also described. As the thrombospondin type 1 repeat motifs represent an increasingly large part of the protein during Deuterostomia evolution, the duplication mechanisms leading to this complex organization are examined. The functional significance of the particularly well-preserved arrangement of the series of SCO-spondin repeat motifs and thombospondin type 1 repeats is discussed

Use Of SCO-Spondin Peptides For Inhibiting Or Preventing Neuronal Apoptosis Mediated By Cell Death Receptor Ligands

The invention relates to a polypeptide derived from the TSR (thrombospondin type 1 units) of SCO-Spondin for inhibiting or preventing the apoptosis mediated by the cell death receptor ligands, such as TRAIL or FasL. The polypeptide of the invention comprises a sequence -W-S-A1-C-S-A2-C-G- wherein A1 and A2 are amino acid sequences comprising 1 to 5 amino acids. More particularly, the invention relates to said polypeptide for inhibiting or preventing the apoptosis associated with a disease selected from the group consisting of neurodegenerative disorders, cerebral ischemia, neuronal traumas, neuronal inflammatory diseases, and viral neurodegenerations

SCO-spondine (rôle dans la survie et la différenciation cellulaire in vitro et in vivo)

La SCO-spondine est une glycoprotéine de grande taille qui est sécrétée par l'organe sous commissural. Elle comprend de nombreux domaines dont 26 motifs thrombospondin type 1 repeats (TSR) et appartient à la superfamille des protéines à motifs TSR. Certaines des protéines de cette famille sont exprimées dans le système nerveux central comme la thrombospondine 1 et la F-spondine. Ces protéines jouent un rôle dans le guidage axonal et la migration cellulaire pendant le développement du SNC et elles sont capables d'induire une synaptogenèse. En utilisant un peptide de séquence connu et dérivé des acides aminés les plus conservés des domaines TSR de la SCO-spondine, nous en avons étudiés les effets sur la différenciation neuronale et sur les phénomènes de survie/apoptose sur des modèles in vitro (modèle de cellules B104, modèle de cultures primaires de neurones corticaux d'embryon de rat et modèle de culture primaire d'hépatocytes de rat) et in vivo (modèle de section de nerf olfactif chez le poussin) par différentes techniques de biologie cellulaire et de biologie moléculaire. Le peptide est capable d'induire une différenciation des cellules nerveuses qu'elles soient issues de la lignée des cellules B104 ou de cultures primaires de neurones corticaux ainsi qu'une synaptogenèse dans les cultures de cellules B104. Le peptide TSR ne présente pas de toxicité pour des cultures d'hépatocytes de rat et possède aussi un effet neuroprotecteur pour les cellules de l'épithélium olfactif dans le modèle d'apoptose induite par lésion du nerf olfactif chez le poussin. De part ces propriétés neuroréparatrice et neuroprotectrice, ce peptide présente un intérêt pour un futur développement clinique.SCO-spondin is a large glycoprotein secreted by the subcommissural organ. This protein contains various domains including 26 thrombospondin type 1 repeats (TSR) and belongs to the superfamily of proteins with TSR domains. Some proteins of this superfamily like thrombospondin-1 or F-spondin expressed in the CNS have been shown to play a role in axonal pathfinding and cell migration during the CNS development and they can induce synaptogenesis. Using a TSR peptide derived from the most highly conserved amino acids of SCO-spondin TSR domains, we investigated its effect on neuronal differentiation and survey/apoptosis balance on in vitro models (B104 cells, primary cultures of cortical neurons, hepatocytes) and in vivo models (lesion of chicken olfactory nerve) using cellular and molecular biology methods. TSR peptide induces differentiation ans synaptogenesis in B104 cells cultures and primary cultures of cortical neurons. TSR peptide has no toxicity on primary cultures of hepatocytes and has also a neuroprotective effect on cells of olfactory epithelium after olfactory nerve section. Regarding these neuroregenerative and neuroprotective capacities, TSR peptide derived from SCO-spondin could be a useful tool in treatment of neurodegenerative diseases or CNS traumas after clinical development.CLERMONT FD-BCIU-Santé (631132104) / SudocSudocFranceF

The lengthening of a giant protein: When, how, and why?

International audienceSubcommissural organ (SCO)-spondin is a giant glycoprotein of more than 5000 amino acids found in Vertebrata, expressed in the central nervous system and constitutive of Reissner’s fiber. For the first time, in situ hybridization performed on zebrafish (Danio rerio) embryos shows that the gene encoding this protein is expressed transitionally in the floor plate, the ventral midline of the neural tube, and later in the diencephalic third ventricle roof, the SCO. The modular organization of the protein in Echinodermata (Strongylocentrotus purpuratus), Urochordata (Ciona savignyi and C. intestinalis), and Vertebrata (Teleostei, Amphibia, Aves and Mammalia) is also described. As the thrombospondin type 1 repeat motifs represent an increasingly large part of the protein during Deuterostomia evolution, the duplication mechanisms leading to this complex organization are examined. The functional significance of the particularly well-preserved arrangement of the series of SCO-spondin repeat motifs and thombospondin type 1 repeats is discussed

The Thrombospondin Type 1 Repeat (TSR) and Neuronal Differentiation: Roles of SCO-Spondin Oligopeptides on Neuronal Cell Types and Cell Lines∗

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Mouse SCO-spondin, a gene of the thrombospondin type 1 repeat (TSR) superfamily expressed in the brain

International audienceSCO-spondin is specifically expressed in the subcommissural organ (SCO), a secretory ependymal differentiation lining the roof of the third ventricular cavity of the brain. When released into the cerebro-spinal fluid (CSF), SCO-spondin aggregates and forms Reissner's fiber (RF), a structure present in the central canal of the spinal cord. SCO-spondin belongs to the superfamily of proteins exhibiting conserved motifs called TSRs for 'thrombospondin type 1 repeats' and involved in axonal pathfinding during development. The mouse SCO-spondin coding sequence was searched by alignement of the coding bovine SCO-spondin sequence with the mouse whole genome shotgun (WGS) supercontig (NW 000250). Compared to the bovine, mouse SCO-spondin shows 66.8% identity of amino acids. This extracellular matrix glycoprotein has a modular arrangement of several conserved domains including 25 TSRs, 10 low-density lipoprotein receptor (LDLr) type A repeats and cystein-rich regions in the -NH2 and -COOH ends. The spatio-temporal expression of SCO-spondin was analyzed using specific antisera and an homospecific SCO-spondin riboprobe. In the adult, the patterns obtained by in situ hybridization (ISH) and immunohistochemistry correlated well in the SCO, while Reissner's fiber and the ampulla caudalis were immunoreactive only. In the fetus, both the immuno and ISH reactions appeared between 14 and 15 days post coïtum (dpc) in the SCO anlage. In addition, the mouse SCO-spondin gene was located at chromosome 6, between marker D6Mit352 and D6Mit119, in a conserved syntenic region

Placental expression of SCO-spondin during mouse and human development

International audienceDuring mammalian development, the placenta is a transitory but indispensable structure for a harmonious gestation involving several biological processes, such as adhesion, differentiation, apoptosis or cellular guidance. Nevertheless, the molecular pathways implicated during the placentation are still not totally understood. We previously described, the subcommissural organ (SCO)-spondin, a member of the 'thrombospondin' super-family, which is strongly expressed during mammalian central nervous system development. This extra-cellular matrix glycoprotein shows a unique arrangement of several conserved domains, including thrombospondin type 1 repeats, low-density lipoprotein receptor type A domains, two epidermal growth factor-like domains, and N- and C-terminal von Willebrand factor cysteine-rich domains. The presence of these domains strongly suggests the SCO-spondin involvement in cellular events occurring during placental development and physiology. In order to define this new role of SCO-spondin during development, we demonstrated its expression at relevant steps of gestation in human and mouse placenta, using RT-PCR, immunohistochemistry and Western-blot experiments. These data initiate further insights into the molecular and genetic functions of the neuronal gene SCO-spondin during trophoblastic and more globally during placental physiology and development

SCO-Spondin Derived Peptide NX210 Induces Neuroprotection In Vitro and Promotes Fiber Regrowth and Functional Recovery after Spinal Cord Injury

International audienceIn mammals, the limited regenerating potential of the central nervous system (CNS) in adults contrasts with the plasticity of the embryonic and perinatal periods. SCO (subcommissural organ)-spondin is a protein secreted early by the developing central nervous system, potentially involved in the development of commissural fibers. SCO-spondin stimulates neuronal differentiation and neurite growth in vitro. NX210 oligopeptide was designed from SCO-spondin's specific thrombospondin type 1 repeat (TSR) sequences that support the main neurogenic properties of the molecule. The objective of this work was to assess the neuroprotective and neuroregenerative properties of NX210 in vitro and in vivo for the treatment of spinal cord injury (SCI). In vitro studies were carried out on the B104 neuroblastoma cell line demonstrating neuroprotection by the resistance to oxidative damage using hydrogen peroxide and the measure of cell viability by metabolic activity. In vivo studies were performed in two rat models of SCI: (1) a model of aspiration of dorsal funiculi followed by the insertion of a collagen tube in situ to limit collateral sprouting; white matter regeneration was assessed using neurofilament immunostaining; (2) a rat spinal cord contusion model to assess functional recovery using BBB scale and reflex testing. We demonstrate for the first time that NX210 (a) provides neuroprotection to oxidative stress in the B104 neuroblastoma cells, (b) stimulates axonal regrowth in longitudinally oriented neofibers in the aspiration model of SCI and (c) significantly improves functional recovery in the contusive model of SCI

Drosophila melanogaster P-glycoprotein : A membrane detoxification system toward polycyclic aromatic hydrocarbon pollutants

International audiencePolycyclic aromatic hydrocarbons (PAHs) are well-known ubiquitous environmental contaminants. Permeability glycoprotein (P-gp) is a transmembrane detoxification efflux pump transporting various lipophilic xenobiotics, such as PAHs, out of the cells. The existence of a P-gp detoxification system inducible by PAHs was investigated in Drosophila melanogaster. Western blot experiments showed that D. melanogaster expressed a 140-kDa P-gp in S12 cells, embryos, and adult flies. Permeability glycoprotein was expressed in adult flies in the head, abdomen, and thorax and sublocalized in the sexual and olfactory organs. Flow cytometry experiments using Drosophila S12 cells in the presence of PAHs and target P-gp drug compounds revealed that Drosophila P-gp acted as an efflux detoxification pump. In Drosophila exposed to benzo[a]pyrene or to ambient air polluted by higher or lower PAH concentrations, P-gp expression was clearly showed a dose-dependent increase response. The P-gp induction was detected both in adult flies and in different fly parts, such as the head, thorax, and antennae. Drosophila P-gp acts as a membrane barrier against PAH pollutants