Endoglin overexpression modulates cellular morphology, migration, and adhesion of mouse fibroblasts

10 p.-9 fig.-1 tab.Endoglin is the gene mutated in hereditary hemorrhagic telangiectasia type 1 (HHT1), a dominantly inherited vascular disorder. Endoglin glycoprotein is a component of the transforming growth factor type ß (TGF-ß) receptor system which is highly expressed by endothelial cells, and at lower levels on fibroblasts and smooth muscle cells, suggesting the involvement of these lineages in the HHT1 vascular dysplasia. Overexpression of endoglin in mouse NCTC929 fibroblasts led to decreased migration in chemotactic and wound healing assays, as well as changes in the cellular morphology. When plated on uncoated surfaces, endoglin transfectants formed intercellular clusters, endoglin being not specifically localized to the cell-cell junctions, but homogenously distributed on the cellular surface. Although the expression of α5ß1 integrin and of an activation epitope of ß1 integrin were unchanged, a polyclonal antibody to α5ß1 integrin was able to inhibit cluster formation, suggesting the involvement of integrin ligand/s. In fact, coating with fibronectin, laminin, or an RGD-containing 80 kDa fragment of fibronectin were able to prevent the cellular clustering. Furthermore, synthesis of plasminogen activator inhibitor 1 (PAI-1), and to a weak extent that of fibronectin, were inhibited in endoglin transfectants. Thus, the presence of endoglin in mouse NCTC929 fibroblasts is associated with reduced production of certain extracellular matrix (ECM) components, which might explain their altered morphology, migration and intercellular cluster formation.This work has been supported by grants from Camisión Interministerial de Ciencia yTecnología (CICYT-SAF97-0034 to C. Bernabéu, and CICYT-SAF97-0064-C03-02 to A. García-Pardo), Comunidad Autónoma de Madrid (CAM) and Biomed Program of the European Community (BMH4-CT95-0995 to C. Bernabéu).Peer reviewe

Expression of normal and truncated forms of human endoglin.

Endoglin is a transmembrane glycoprotein 633 residues in length expressed at the surface of endothelial cells as a disulphide-linked homodimer; the specific cysteine residues involved in endoglin dimerization are unknown. Mutations in the coding region of the endoglin gene are responsible for hereditary haemorrhagic telangiectasia type 1 (HHT1), a dominantly inherited vascular disorder. Many of these mutations, if translated, would lead to truncated forms of the protein. It is therefore of interest to assess the protein expression of different truncated forms of endoglin. Infections in vitro or in vivo with recombinant vaccinia virus, as well as transient transfections with expression vectors, were used to express normal and truncated forms of endoglin. Truncated mutants could be classified into three different groups: (1) those that did not produce stable transcripts; (2) those that produced stable transcripts but did not secrete the protein; and (3) those that secreted a soluble dimeric protein. This is the first time that a recombinant truncated form of endoglin has been found to be expressed in a soluble form. Because a chimaeric construct encoding the N-terminal sequence of platelet/endothelial cell adhesion molecule (PECAM-1) antigen fused to residues Ile281-Ala658 of endoglin also yielded a dimeric surface protein, these results suggest that cysteine residues contained within the fragment Cys330-Cys412 are involved in disulphide bond formation. Infection with vaccinia recombinants encoding an HHT1 mutation did not affect the expression of the normal endoglin, and did not reveal an association of the recombinant soluble form with the transmembrane endoglin, supporting a haploinsufficiency model for HHT1

Spanish nationalism: ethnic or civic?

ABSTRACT In recent years, it has been a common complaint among scholars to acknowledge the lack of research on Spanish nationalism. This article addresses the gap by giving an historical overview of ‘ethnic ’ and ‘civic ’ Spanish nationalist discourses during the last two centuries. It is argued here that Spanish nationalism is not a unified ideology but it has, at least, two varieties. During the 19th-century, both a ‘liberal ’ and a ‘conservative-traditionalist ’ nationalist discourse were formu-lated and these competed against each other for hegemony within the Spanish market of ideas. In the 20th-century, these two discourses continued to be present and became backbones of different political regimes. However, after the emergence of the Basque and Catalan nationalist movements, Spanish nationalists unified as a counter-force to these regional sources of identity. In fact, one can see 20th-century Spanish nationalism as a dialectical struggle between the centre and the periphery