Fabrice Lavial

Publications (7)29.31 Total impact

• Article: Pluripotent genes in avian stem cells.

  Christian Jean, Pauline Aubel, Clément Soleihavoup, Frantz Bouhallier, Sophie Voisin, Fabrice Lavial, Bertrand Pain
  [show abstract] [hide abstract]
  ABSTRACT: Embryonic stem (ES) cells were first isolated in 1981 in the mouse from the in vitro proliferation of the inner cell mass of a 3.5 days post-coitum (dpc) blastocyst. Later on, epiblast stem cells (EpiSC) were identified from in vitro culture of the epiblast of a 6.5 dpc mouse embryo, leading to the concept of naïve and primed stem cells. Among non-mammalian species, ES cells have been characterized both in birds and fish; here, we focus on cells derived from chicken and the pluripotent associated markers such as OCT4, SOX2, NANOG, and KLF, previously identified in mammalian cells. In this review, we present both published and original data regarding the involvement of those pluripotent associated genes in the ES cells and early embryo of chicken.
  Embryologia 12/2012; · 2.21 Impact Factor
• Article: Astacin-like metallo-endopeptidase is dynamically expressed in embryonic stem cells and embryonic epithelium during morphogenesis.

  Hervé Acloque, Fabrice Lavial, Bertrand Pain
  [show abstract] [hide abstract]
  ABSTRACT: Astacin-like metallo-proteases are zinc endopeptidases conserved among vertebrates and invertebrates. First described as hatching gland enzymes, many members of the family possess other functions during embryonic development. In the chick, however, functions of Astacin-like proteins remain elusive. We report here that Astacin-like (ASTL) is strongly expressed in mouse and chicken embryonic stem (ES) cells and exhibits a very dynamic expression pattern during embryogenesis and organogenesis, mostly in remodeled epithelia. Consistent with its expression in ES cells, chick ASTL is detected in vivo in the pluripotent cells of the epiblast and then disappears from the newly induced neural plate. ASTL expression remains at the junction of non-neural and neural ectoderm, just before neural tube closure. At later stages, chick ASTL is detected in the ventral epidermis before ventral closure, in the intermediate mesoderm, in the gonads and in the forming nephric duct and tubules of the mesonephros and metanephros. ASTL is dynamically expressed in the embryonic epithelium and in embryonic stem cells, suggesting an important function for the control of epithelial cell behavior during early development.
  Developmental Dynamics 03/2012; 241(3):574-82. · 2.54 Impact Factor
• Article: Reprogramming capacity of Nanog is functionally conserved in vertebrates and resides in a unique homeodomain.

  Thorold W Theunissen, Yael Costa, Aliaksandra Radzisheuskaya, Anouk L van Oosten, Fabrice Lavial, Bertrand Pain, L Filipe C Castro, José C R Silva
  [show abstract] [hide abstract]
  ABSTRACT: Pluripotency is a developmental ground state that can be recreated by direct reprogramming. Establishment of pluripotency is crucially dependent on the homeodomain-containing transcription factor Nanog. Compared with other pluripotency-associated genes, however, Nanog shows relatively low sequence conservation. Here, we investigated whether Nanog orthologs have the capacity to orchestrate establishment of pluripotency in Nanog(-/-) somatic cells. Mammalian, avian and teleost orthologs of Nanog enabled efficient reprogramming to full pluripotency, despite sharing as little as 13% sequence identity with mouse Nanog. Nanog orthologs supported self-renewal of pluripotent cells in the absence of leukemia inhibitory factor, and directly regulated mouse Nanog target genes. Related homeodomain transcription factors showed no reprogramming activity. Nanog is distinguished by the presence of two unique residues in the DNA recognition helix of its homeodomain, and mutations in these positions impaired reprogramming. On the basis of genome analysis and homeodomain identity, we propose that Nanog is a vertebrate innovation, which shared an ancestor with the Bsx gene family prior to the vertebrate radiation. However, cephalochordate Bsx did not have the capacity to replace mouse Nanog in reprogramming. Surprisingly, the Nanog homeodomain, a short sequence that contains the only recognizable conservation between Nanog orthologs, was sufficient to induce naive pluripotency in Nanog(-/-) somatic cells. This shows that control of the pluripotent state resides within a unique DNA-binding domain, which appeared at least 450 million years ago in a common ancestor of vertebrates. Our results support the hypothesis that naive pluripotency is a generic feature of vertebrate development.
  Development 11/2011; 138(22):4853-65. · 6.60 Impact Factor
• Article: Role of miR-34c microRNA in the late steps of spermatogenesis.

  Frantz Bouhallier, Nathalie Allioli, Fabrice Lavial, Frédéric Chalmel, Marie-Hélène Perrard, Philippe Durand, Jacques Samarut, Bertrand Pain, Jean-Pierre Rouault
  [show abstract] [hide abstract]
  ABSTRACT: Spermatogenesis is a cyclic process in which diploid spermatogonia differentiate into haploid spermatozoa. This process is highly regulated, notably at the post-transcriptional level. MicroRNAs (miRNAs), single-stranded noncoding RNA molecules of about 20-25 nucleotides, are implicated in the regulation of many important biological pathways such as proliferation, apoptosis, and differentiation. We wondered whether miRNAs could play a role during spermatogenesis. The miRNA expression repertoire was tested in germ cells, and we present data showing that miR-34c was highly expressed only in these cells. Furthermore, our findings indicate that in male gonads, miR-34c expression is largely p53 independent in contrast to previous results showing a direct link in somatic cells between the miR-34 family and this tumor suppressor protein. In order to identify target genes involved in germinal lineage differentiation, we overexpressed miR-34c in HeLa cells, analyzed the transcriptome of these modified cells, and noticed a shift of the expression profile toward the germinal lineage. Recently, it has been shown that exogenous expression of Ddx4/Vasa in embryonic chicken stem cells (cESC) induces cESC reprogramming toward a germ cell fate. When we simultaneously expressed miR-34c in such cells, we could detect an up-regulation of germ cell-specific genes whereas the expression of other lineage specific markers remained unchanged. These data suggest that miR-34c could play a role by enhancing the germinal phenotype of cells already committed to this lineage.
  RNA 02/2010; 16(4):720-31. · 5.09 Impact Factor
• Source

  Available from: sbri.fr

  Article: Chicken embryonic stem cells as a non-mammalian embryonic stem cell model.

  Fabrice Lavial, Bertrand Pain
  [show abstract] [hide abstract]
  ABSTRACT: Embryonic stem cells (ESCs) were isolated in the early 1980s from mouse and in the late 1990s from primate and human. These cells present the unique property of self-renewal and the ability to generate differentiated progeny in all embryonic lineages both in vitro and in vivo. The mESCs (mouse embryonic stem cells) can contribute to both somatic and germinal lineages once re-injected into a recipient embryo at the blastocyst stage. In avian species, chicken embryonic stem cells (cESCs) have been isolated from the in vitro culture of early chicken blastodermal cells (cBCs) taken from stage X embryo (EG&K) These cESCs can be maintained under specific culture conditions and have been characterized on the basis of their morphology, biochemical features, in vitro differentiation potentialities and in vivo morphogenetic properties. The relationship between these cESCs and some of the chicken germ cells identified and grown under specific culture conditions are still under debate, in particular with the identification of the Cvh gene as a key factor for germ cell determination. Moreover, by cloning the avian homologue of the Oct4 mammalian gene, we have demonstrated that this gene, as well as the chicken Nanog gene, was involved in the characterization and maintenance of the chicken pluripotency. These first steps toward the understanding of pluripotency control in a non-mammalian species opens the way for the development and characterization of putative new cell types such as chicken EpiSC and raises the question of the existence of reprogramming in avian species. These different points are discussed.
  Embryologia 01/2010; 52(1):101-14. · 2.21 Impact Factor
• Source

  Available from: M. Angela Nieto

  Article: Ectopic expression of Cvh (Chicken Vasa homologue) mediates the reprogramming of chicken embryonic stem cells to a germ cell fate.

  Fabrice Lavial, Hervé Acloque, Elodie Bachelard, M Angela Nieto, Jacques Samarut, Bertrand Pain
  [show abstract] [hide abstract]
  ABSTRACT: When they are derived from blastodermal cells of the pre-primitive streak in vitro, the pluripotency of Chicken Embryonic Stem Cells (cESC) can be controlled by the cPouV and Nanog genes. These cESC can differentiate into derivatives of the three germ layers both in vitro and in vivo, but they only weakly colonize the gonads of host embryos. By contrast, non-cultured blastodermal cells and long-term cultured chicken primordial germ cells maintain full germline competence. This restriction in the germline potential of the cESC may result from either early germline determination in the donor embryos or it may occur as a result of in vitro culture. We are interested in understanding the genetic determinants of germline programming. The RNA binding protein Cvh (Chicken Vasa Homologue) is considered as one such determinant, although its role in germ cell physiology is still unclear. Here we show that the exogenous expression of Cvh, combined with appropriate culture conditions, induces cESC reprogramming towards a germ cell fate. Indeed, these cells express the Dazl, Tudor and Sycp3 germline markers, and they display improved germline colonization and adopt a germ cell fate when injected into recipient embryos. Thus, our results demonstrate that Vasa can drive ES cell differentiation towards the germ cell lineage, both in vitro and in vivo.
  Developmental Biology 04/2009; 330(1):73-82. · 4.07 Impact Factor
• Article: The Oct4 homologue PouV and Nanog regulate pluripotency in chicken embryonic stem cells.

  Fabrice Lavial, Hervé Acloque, Federica Bertocchini, David J Macleod, Sharon Boast, Elodie Bachelard, Guillaume Montillet, Sandrine Thenot, Helen M Sang, Claudio D Stern, Jacques Samarut, Bertrand Pain
  [show abstract] [hide abstract]
  ABSTRACT: Embryonic stem cells (ESC) have been isolated from pregastrulation mammalian embryos. The maintenance of their pluripotency and ability to self-renew has been shown to be governed by the transcription factors Oct4 (Pou5f1) and Nanog. Oct4 appears to control cell-fate decisions of ESC in vitro and the choice between embryonic and trophectoderm cell fates in vivo. In non-mammalian vertebrates, the existence and functions of these factors are still under debate, although the identification of the zebrafish pou2 (spg; pou5f1) and Xenopus Pou91 (XlPou91) genes, which have important roles in maintaining uncommitted putative stem cell populations during early development, has suggested that these factors have common functions in all vertebrates. Using chicken ESC (cESC), which display similar properties of pluripotency and long-term self-renewal to mammalian ESC, we demonstrated the existence of an avian homologue of Oct4 that we call chicken PouV (cPouV). We established that cPouV and the chicken Nanog gene are required for the maintenance of pluripotency and self-renewal of cESC. These findings show that the mechanisms by which Oct4 and Nanog regulate pluripotency and self-renewal are not exclusive to mammals.
  Development 11/2007; 134(19):3549-63. · 6.60 Impact Factor