Biomedical subjects

O G Morali

Publications and source records attributed to O G Morali.

3 recordsLinked to original sources

PubMed2001

IGF-II induces rapid beta-catenin relocation to the nucleus during epithelium to mesenchyme transition.

The epithelium to mesenchyme transition is thought to play a fundamental role during embryonic development and tumor progression. Loss of cell-cell adhesion and modification of both cell morphology and gene expression are the main events associated with this transition. There is a large amount of evidence suggesting that growth factors can initiate these events. Yet, the connection from growth factor induction to changes in cell adhesion and morphology is largely unknown. To elucidate this connection, we have investigated the action of IGF-II on E-cadherin/beta-catenin complex-mediated cell-cell adhesion and on beta-catenin/TCF-3 mediated gene expression. We can show that (1) IGF-II induces a rapid epithelium to mesenchymal transition; (2) IGF1R, the receptor for IGF-II, belongs to the same membrane complex as E-cadherin and beta-catenin; (3) IGF-II induces a redistribution of beta-catenin from the plasma membrane to the nucleus and an intracellular sequestration and degradation of E-cadherin; (4) IGF-II induces the transcription of beta-catenin/TCF-3 target genes. Based on the given case of IGF-II and E-cadherin/beta-catenin complex, this study reveals the backbone of a cascade connecting growth factor signaling with cell-cell adhesion during EMT.

3T3 Cells↗

PubMed2001

Cadherins in neural crest cell development and transformation.

Cadherins constitute a superfamily of cell adhesion molecules involved in cell-cell interaction, histogenesis and cellular transformation. They have been implicated in the development of various lineages, including derivatives of the neural crest. Neural crest cells (NCC) emerge from the dorsal part of the neural tube after an epithelio-mesenchymal transition (EMT) and migrate through the embryo. After homing and differentiation, NCC give rise to many cell types, such as neurons, Schwann cells and melanocytes. During these steps, the pattern of expression of the various cadherins studied is very dynamic. Cadherins also display plasticity of expression during the transformation of neural crest cell derivatives. Here, we review the pattern of expression and the role of the main cadherins involved in the development and transformation of neural crest cell derivatives.

Animals↗

PubMed2000

IGF-II promotes mesoderm formation.

IGF-II is abundant in the nascent mesoderm of the gastrulating mouse embryo. Its function at this developmental stage is unknown. We investigated it by following the in vitro and in vivo differentiation of several androgenetic, biparental, parthenogenetic, and androgenetic Igf2 -/- murine ES cell lines; these cells differed in endogenous IGF-II levels because Igf2 is paternally expressed in the mouse embryo in most tissues. The expression of mesoderm markers and the subsequent formation of muscle structures were correlated with endogenous IGF-II level during teratoma formation and during in vitro differentiation. In addition, the absence of Igf2 in androgenetic Igf2 -/- ES cells led to a severe impairment of mesoderm development, demonstrating the dependence of the preferential mesoderm development of androgenetic ES cells upon Igf2 activity, among the numerous known imprinted genes. The addition of exogenous IGF-II to in vitro differentiation culture medium led to a specific increase in the expression of mesoderm markers. Thus, we propose a novel model in which the binding of IGF-II to its principal signaling receptor, IGF1R, at the surface of mesoderm precursor cells increases the formation of mesoderm cells.

Animals↗