Inhibition of cell migration and invasion mediated by the TAT-RasGAP317-326 peptide requires the DLC1 tumor suppressor.

TAT-RasGAP317-326, a peptide corresponding to the 317-326 sequence of p120 RasGAP coupled with a cell-permeable TAT-derived peptide, sensitizes the death response of various tumor cells to several anticancer treatments. We now report that this peptide is also able to increase cell adherence, prevent cell migration and inhibit matrix invasion. This is accompanied by a marked modification of the actin cytoskeleton and focal adhesion redistribution. Interestingly, integrins and the small Rho GTP-binding protein, which are well-characterized proteins modulating actin fibers, adhesion and migration, do not appear to be required for the pro-adhesive properties of TAT-RasGAP317-326. In contrast, deleted in liver cancer-1, a tumor suppressor protein, the expression of which is often deregulated in cancer cells, was found to be required for TAT-RasGAP317-326 to promote cell adherence and inhibit migration. These results show that TAT-RasGAP317-326, besides its ability to favor tumor cell death, hampers cell migration and invasion.

The nuclear hormone receptor peroxisome proliferator-activated receptor beta/delta potentiates cell chemotactism, polarization, and migration.

After an injury, keratinocytes acquire the plasticity necessary for the reepithelialization of the wound. Here, we identify a novel pathway by which a nuclear hormone receptor, until now better known for its metabolic functions, potentiates cell migration. We show that peroxisome proliferator-activated receptor beta/delta (PPARbeta/delta) enhances two phosphatidylinositol 3-kinase-dependent pathways, namely, the Akt and the Rho-GTPase pathways. This PPARbeta/delta activity amplifies the response of keratinocytes to a chemotactic signal, promotes integrin recycling and remodeling of the actin cytoskeleton, and thereby favors cell migration. Using three-dimensional wound reconstructions, we demonstrate that these defects have a strong impact on in vivo skin healing, since PPARbeta/delta-/- mice show an unexpected and rare epithelialization phenotype. Our findings demonstrate that nuclear hormone receptors not only regulate intercellular communication at the organism level but also participate in cell responses to a chemotactic signal. The implications of our findings may be far-reaching, considering that the mechanisms described here are important in many physiological and pathological situations.

Blocking Junctional Adhesion Molecule C Enhances Dendritic Cell Migration and Boosts the Immune Responses against Leishmania major.

The recruitment of dendritic cells to sites of infections and their migration to lymph nodes is fundamental for antigen processing and presentation to T cells. In the present study, we showed that antibody blockade of junctional adhesion molecule C (JAM-C) on endothelial cells removed JAM-C away from junctions and increased vascular permeability after L. major infection. This has multiple consequences on the output of the immune response. In resistant C57BL/6 and susceptible BALB/c mice, we found higher numbers of innate immune cells migrating from blood to the site of infection. The subsequent migration of dendritic cells (DCs) from the skin to the draining lymph node was also improved, thereby boosting the induction of the adaptive immune response. In C57BL/6 mice, JAM-C blockade after L. major injection led to an enhanced IFN-γ dominated T helper 1 (Th1) response with reduced skin lesions and parasite burden. Conversely, anti JAM-C treatment increased the IL-4-driven T helper 2 (Th2) response in BALB/c mice with disease exacerbation. Overall, our results show that JAM-C blockade can finely-tune the innate cell migration and accelerate the consequent immune response to L. major without changing the type of the T helper cell response.

Statistical discrimination and employers' recruitment : Practices for low-skilled workers

This paper deals with the recruitment strategies of employers in the low-skilled segment of the labour market. We focus on low-skilled workers because they are overrepresented among jobless people and constitute the bulk of the clientele included in various activation and labour market programmes. A better understanding of the constraints and opportunities of interventions in this labour market segment may help improve their quality and effectiveness. On the basis of qualitative interviews with 41 employers in six European countries, we find that the traditional signals known to be used as statistical discrimination devices (old age, immigrant status and unemployment) play a somewhat reduced role, since these profiles are overrepresented among applicants for low skill positions. However, we find that other signals, mostly considered to be indicators of motivation, have a bigger impact in the selection process. These tend to concern the channel through which the contact with a prospective candidate is made. Unsolicited applications and recommendations from already employed workers emit a positive signal, whereas the fact of being referred by the public employment office is associated with the likelihood of lower motivation.

Insulin modulation of luteinizing hormone secretion in normal female volunteers and lean polycystic ovary syndrome patients.

BACKGROUND/AIMS: Endocrine features of polycystic ovary syndrome (PCOS) include altered ovarian steroidogenesis, hyperinsulinemia and abnormal luteinizing hormone (LH) secretion. This study was undertaken to further evaluate the role of insulin to modulate LH secretion in lean PCOS patients with normal insulin sensitivity and normal volunteers. METHODS: The study was performed in five nonobese patients diagnosed with PCOS on the basis of amenorrhea and a polycystic morphology at ovarian ultrasound, and 5 normal controls in early to mid-follicular phase and matched for weight and age. All subjects were phenotyped, and then admitted for 12 h of frequent (q 10') blood sampling on two separate occasions, once for a baseline study and the other time for a hyperinsulinemic and euglycemic clamp study. LH was measured in samples obtained throughout each admission in order to perform LH pulse analysis. RESULTS: Baseline LH secretion in PCOS subjects was significantly different from controls: they had higher LH levels, higher LH/FSH ratios as well as a faster LH pulse frequency than normal women. Insulin administration did not affect the pattern of LH secretion of PCOS patients, whereas it significantly increased the LH pulse frequency while decreasing the LH interpulse intervals in the controls. CONCLUSIONS: These data confirm that an abnormal pattern of LH secretion characteristic of PCOS can be observed in lean patients, and appears independent of peripheral insulin levels. Furthermore, our results in lean controls provide the first direct evidence that peripheral insulin can modulate the activity of hypothalamic gonadotropin-releasing hormone (GnRH) neurons in the human.

Comprehensive spatiotemporal transcriptomic analyses of the ganglionic eminences demonstrate the uniqueness of its caudal subdivision.

The elucidation of mechanisms underlying telencephalic neural development has been limited by the lack of knowledge regarding the molecular and cellular aspects of the ganglionic eminence (GE), an embryonic structure that supplies the brain with diverse sets of GABAergic neurons. Here, we report a comprehensive transcriptomic analysis of this structure including its medial (MGE), lateral (LGE) and caudal (CGE) subdivisions and its temporal dynamics in 12.5 to 16 day-old rat embryos. Surprisingly, comparison across subdivisions showed that CGE gene expression was the most unique providing unbiased genetic evidence for its differentiation from MGE and LGE. The molecular signature of the CGE comprised a large set of genes, including Rwdd3, Cyp26b1, Nr2f2, Egr3, Cpta1, Slit3, and Hod, of which several encode cell signaling and migration molecules such as WNT5A, DOCK9, VSNL1 and PRG1. Temporal analysis of the MGE revealed differential expression of unique sets of cell specification and migration genes, with early expression of Hes1, Lhx2, Ctgf and Mdk, and late enrichment of Olfm3, SerpinE2 and Wdr44. These GE profiles reveal new candidate regulators of spatiotemporally governed GABAergic neuronogenesis.

Preparation, maintenance, and use of serum-free aggregating brain cell cultures.

Serum-free aggregating brain cell cultures are free-floating three-dimensional primary cell cultures able to reconstitute spontaneously a histotypic brain architecture to reproduce critical steps of brain development and to reach a high level of structural and functional maturity. This culture system offers, therefore, a unique model for neurotoxicity testing both during the development and at advanced cellular differentiation, and the high number of aggregates available combined with the excellent reproducibility of the cultures facilitates routine test procedures. This chapter presents a detailed description of the preparation, maintenance, and use of these cultures for neurotoxicity studies and a comparison of the developmental characteristics between cultures derived from the telencephalon and cultures derived from the whole brain. For culture preparation, mechanically dissociated embryonic brain tissue is used. The initial cell suspension, composed of neural stem cells, neural progenitor cells, immature postmitotic neurons, glioblasts, and microglial cells, is kept in a serum-free, chemically defined medium under continuous gyratory agitation. Spherical aggregates form spontaneously and are maintained in suspension culture for several weeks. Within the aggregates, the cells rearrange and mature, reproducing critical morphogenic events, such as migration, proliferation, differentiation, synaptogenesis, and myelination. For experimentation, replicate cultures are prepared by the randomization of aggregates from several original flasks. The high yield and reproducibility of the cultures enable multiparametric endpoint analyses, including "omics" approaches.

Female adolescents' views on a youth-friendly clinic

Rapport de synthèse : La satisfaction des patients concernant leur prise en charge fait maintenant partie intégrante de la qualité des soins. Elle a été évaluée à maintes reprises chez des patients adultes ou pédiatriques, mais rarement chez des patients adolescents. Les attentes des adolescents par rapport aux services de soins ont par contre été souvent étudiées et certains facteurs semblent particulièrement importants. Parmi ceux-ci, citons la confidentialité, le respect, l'honnêteté, l'écoute, l'accès aux soins ou le fait d'avoir des informations compréhensibles. L'Organisation Mondiale de la Santé a développé le concept de 'Youth-friendly health services' pour répondre aux besoins et attentes particuliers des adolescents. Il est basé sur sept principes : l'accessibilité, l'équité, l'efficience, l'efficacité, le fait d'être approprié et compréhensible. Notre objectif était d'évaluer la satisfaction des adolescentes consultant dans une clinique multidisciplinaire pour adolescents basée sur le modèle 'Youth-friendly health services' et de déterminer les facteurs qui y sont associés. Nous avons fait une enquête transversale dans une clinique pour adolescents à Lausanne entre mars et mai 2008 moyennant un questionnaire anonyme auto-administré. Tous les patients qui avaient consulté au moins une fois auparavant étaient éligibles. Nous avons ensuite éliminé les garçons, en très petit nombre et donc de faible valeur statistique. Trois cents onze patientes âgées de 12 à 22 ans ont été inclues dans l'étude. Nous avons effectué des analyses bivariées pour comparer les patientes satisfaites et non satisfaites puis avons construit un modèle log- linéaire afin de déterminer les facteurs directement ou indirectement liés à la satisfaction des patientes. Nonante-quatre pourcent des patientes étaient satisfaites. Les facteurs significativement associés à la satisfaction des adolescentes étaient les suivants : Les jeunes filles se sentaient plus écoutées en ce qui concerne leurs plaintes, et avaient plus l'impression que le soignant les comprenait. Elles avaient aussi moins changé de soignant durant le suivi, avaient plus l'impression d'avoir bénéficié du traitement adéquat et pensaient avoir plus suivi les conseils du soignant. Le modèle log-linéaire que nous avons effectué a mis en avant quatre facteurs directement liés à la satisfaction des patientes, qui sont la continuité des soins, le résultat de la prise en charge, l'adhérence au traitement et le sentiment d'être comprise par le soignant. Ces résultats mettent en avant l'importance de la relation interpersonnelle entre le soignant et le patient, mais rendent aussi attentif à des aspects qui pourraient être améliorés, en ce qui concerne par exemple la continuité des soins. En effet, une clinique comme la nôtre fait partie d'un hôpital de formation et le tournus fréquent des soignants est inévitable. Les changements de médecins et autres soignants devraient alors être préparés et expliqués aux patients avec la plus grande attention. L'adhérence au traitement semble être fortement liée à la satisfaction des patients, mais la nature de notre étude ne permet pas de conclure à une relation de cause à effet. Nous pouvons tout de même supposer qu'elle est une conséquence de la satisfaction des patients. Enfin, la confidentialité et l'accès aux soins souvent cités comme essentiels à la satisfaction des patients dans la littérature étaient secondaires dans notre étude. En conclusion, la satisfaction des adolescentes était principalement basée sur une relation de confiance de longue durée avec leurs soignants. Les pédiatres occupent une place privilégiée pour répondre à ces besoins parce qu'ils connaissent leurs patients depuis l'enfance. Ils devraient cependant garder à l'esprit que la relation avec le patient change au moment de l'adolescence et que les jeunes sont très sensibles à la relation de confiance interpersonnelle qu'ils ont avec leur médecin.

New insights into the role of PPARs.

Peroxisome proliferator-activated receptors (PPARs) are fatty acid-activated transcription factors belonging to the nuclear hormone receptor family. While PPARs are best known as regulators of energy homeostasis, evidence also has accumulated recently for their involvement in basic cellular functions. We review novel insights into PPAR functions in skin wound healing and liver, with emphasis on PPARβ/δ and PPARα, respectively. Activation of PPARβ/δ expression in response to injury promotes keratinocyte survival, directional sensing, and migration over the wound bed. In addition, interleukin (IL)-1 produced by the keratinocytes activates PPARβ/δ expression in the underlying fibroblasts, which hinders the mitotic activity of keratinocytes via inhibition of IL-1 signaling. Initially, roles were identified for PPARα in fatty acid catabolism. However, PPARα is also involved in downregulating many genes in female mammals. We have elucidated the mechanism of this repression, which requires sumoylation of PPARα. Physiologically, this control confers protection against estrogen-induced intrahepatic cholestasis.

Up-regulation of macrophage migration inhibitory factor gene and protein expression in glial tumor cells during hypoxic and hypoglycemic stress indicates a critical role for angiogenesis in glioblastoma multiforme.

Glioblastoma multiforme (GBM) is the most malignant variant of human glial tumors. A prominent feature of this tumor is the occurrence of necrosis and vascular proliferation. The regulation of glial neovascularization is still poorly understood and the characterization of factors involved in this process is of major clinical interest. Macrophage migration inhibitory factor (MIF) is a pleiotropic cytokine released by leukocytes and by a variety of cells outside of the immune system. Recent work has shown that MIF may function to regulate cellular differentiation and proliferation in normal and tumor-derived cell lines, and may also contribute to the neovascularization of tumors. Our immunohistological analysis of MIF distribution in GBM tissues revealed the strong MIF protein accumulation in close association with necrotic areas and in tumor cells surrounding blood vessels. In addition, MIF expression was frequently associated with the presence of the tumor-suppressor gene p53. To substantiate the concept that MIF might be involved in the regulation of angiogenesis in GBM, we analyzed the MIF gene and protein expression under hypoxic and hypoglycemic stress conditions in vitro. Northern blot analysis showed a clear increase of MIF mRNA after hypoxia and hypoglycemia. We could also demonstrate that the increase of MIF transcripts on hypoxic stress can be explained by a profound transcriptional activation of the MIF gene. In parallel to the increase of MIF transcripts, we observed a significant rise in extracellular MIF protein on angiogenic stimulation. The data of our preliminary study suggest that the up-regulation of MIF expression during hypoxic and hypoglycemic stress might play a critical role for the neovascularization of glial tumors.

Preoperative percutaneous portal vein embolization: evaluation of adverse events in 188 patients.

PURPOSE: To retrospectively assess the frequency of adverse events related to percutaneous preoperative portal vein embolization (PPVE). MATERIALS AND METHODS: Institutional review board did not require its approval or patient informed consent for this study. The adverse events that occurred during PPVE or until planned hepatic surgery was performed or cancelled were retrospectively obtained from clinical, imaging, and laboratory data files in 188 patients (109 male and 79 female patients; mean age, 60 years; range, 16-78 years). Liver resection was planned for metastases (n = 137), hepatocarcinoma (n = 31), cholangiocarcinoma (n = 15), fibrolamellar hepatoma (n = 1), and benign disease (n = 4). PPVE was performed with a single-lumen 5-F catheter and a contralateral approach with n-butyl cyanoacrylate mixed with iodized oil as the main embolic agent. The rate of complications in patients with cirrhosis was compared with that in patients without cirrhosis by using the chi(2) test. RESULTS: Adverse events occurred in 24 (12.8%) of 188 patients, including 12 complications and 12 incidental imaging findings. Complications included thrombosis of the portal vein feeding the future remnant liver (n = 1); migration of emboli in the portal vein feeding the future remnant liver, which necessitated angioplasty (n = 2); hemoperitoneum (n = 1); rupture of a metastasis in the gallbladder (n = 1); transitory hemobilia (n = 1); and transient liver failure (n = 6). Incidental findings were migration of small emboli in nontargeted portal branches (n = 10) and subcapsular hematoma (n = 2). Among the 187 patients in whom PPVE was technically successful, there was a significant difference (P < .001) between the occurrence of liver failure after PPVE in patients with cirrhosis (five of 30) and those without (one of 157). Sixteen liver resections were cancelled due to cancer progression (n = 12), insufficient hypertrophy of the nonembolized liver (n = 3), and complete portal thrombosis (n = 1). CONCLUSION: PPVE is a safe adjuvant technique for hypertrophy of the initially insufficient liver reserve. Post-PPVE transient liver failure is more common in patients with cirrhosis than in those without cirrhosis.