Bipotential mouse embryonic liver (BMEL) cells spontaneously express Pdx1 and Ngn3 but do not undergo further pancreatic differentiation upon Hes1 down-regulation

<p>Abstract</p> <p>Background</p> <p>Liver-to-pancreas conversion offers new possibilities for β-cell engineering for type 1 diabetes therapy. Among conceivable sources of liver cells, we focused on BMEL cells. These untransformed mouse embryonic liver cells have been reproducibly isolated from different inbred mice strains and have the potential to differentiate into hepatocytes and cholangiocytes <it>in vitro </it>and <it>in vivo</it>.</p> <p>Findings</p> <p>Strikingly, we find here that adherent BMEL cells display functional similarities with multipotent pancreatic precursor cells, namely Pdx1 and Ngn3 expression, and further express <it>Hnf6 </it>in floating aggregate culture. Hes1, a direct repressor of Ngn3 and pancreatic endocrine commitment, is expressed in adherent BMEL cells and decreases with time in aggregate culture. However, Hes1 decrease fails to initiate activation of late-stage pancreatic endocrine transcription factors.</p> <p>Conclusion</p> <p>Here we report that BMEL cells present features of pancreatic endocrine progenitor cells. In the field of diabetes research, BMEL cells are of potential interest for the study of inductive signals critical for in vitro β-cell maturation in-liver-to-pancreas conversion.</p

Pdx-1 or Pdx-1-VP16 protein transduction induces β-cell gene expression in liver-stem WB cells

<p>Abstract</p> <p>Background</p> <p>Pancreatic duodenal homeobox-1 (<it>Pdx-1</it>) or <it>Pdx-1-VP16 </it>gene transfer has been shown to induce <it>in vitro </it>rat liver-stem WB cell conversion into pancreatic endocrine precursor cells. High glucose conditions were necessary for further differentiation into functional insulin-producing cells. Pdx-1 has the ability to permeate different cell types due to an inherent protein transduction domain (PTD). In this study, we evaluated liver-to-pancreas conversion of WB cells following Pdx-1 or Pdx-1-VP16 protein transduction.</p> <p>Findings</p> <p>WB cells were grown in high glucose medium containing Pdx-1 or Pdx-1-VP16 recombinant proteins for two weeks. β-like cell commitment was analysed by RT-PCR of pancreatic endocrine genes. We found that WB cells in high glucose culture spontaneously express pancreatic endocrine genes (<it>Pdx-1, Ngn3, Nkx2.2, Kir6.2</it>). Their further differentiation into β-like cells expressing genes related to endocrine pancreas development (<it>Ngn3, NeuroD, Pax4, Nkx2.2, Nkx6.1, Pdx-1</it>) and β-cell function (<it>Glut-2, Kir6.2, insulin</it>) was achieved only in the presence of Pdx-1(-VP16) protein.</p> <p>Conclusion</p> <p>These results demonstrate that Pdx-1(-VP16) protein transduction is instrumental for <it>in vitro </it>liver-to-pancreas conversion and is an alternative to gene therapy for β-cell engineering for diabetes cell therapy.</p

AsiFood and its output and prospects: An Erasmus+ project on capacity building in food safety and quality for South-East Asia

The Asifood project is a capacity building project in the field of higher education involving collaboration among thirteen partners from Cambodia, Thailand, Vietnam, Austria, Belgium, Italy and France. This project aimed to support the universities in Vietnam, Thailand and Cambodia in building their capacities and their link with professionals in food safety and food quality, in the context of ASEAN integration. Further, training for trainers around a key theme, ‘food safety and quality’ for partner countries was set up involving students and teachers, professional stakeholders, political decision-makers and association leaders. During the first year of the project, study and diagnostic phase were carried out to properly assess the training as per each university needs. In the second year, the training paths around three axes: courses, quality and laboratory analysis were conducted. Finally, a test phase was carried out with the partners by inserting the modules created in the bachelor's and master's degree courses offered by the universities as well as short term trainings on innovations in food safety and quali

TRANSFERT PULMONAIRE DU GENE DU PEPTIDE ATRIAL NATRIURETIQUE VECTORISE PAR UN ADENOVIRUS CHEZ LE RAT : EFFETS SUR L'HYPERTENSION ARTERIELLE PULMONAIRE

L'hypertension artérielle pulmonaire (HTAP) est une pathologie fréquente, fatale dans ses formes graves de l'adulte ou du nouveau-né, dépourvue de traitement en dehors de la transplantation pulmonaire. L'élévation des résistances artérielles pulmonaires est liée à un remaniement hypertrophique de la paroi artérielle et à une réduction du lit vasculaire pulmonaire. L'évolution est celle de la défaillance cardiaque droite. Des études antérieures ont montré que le peptide atrial natriurétique (ANP) endogène aussi bien que l'ANP exogène protégeaient contre le développement de l'hypertension artérielle chronique induite par l'hypoxie chez le rat. Nous avons construit un adénovirus codant pour le gène de l'ANP sous contrôle du promoteur RSV (Ad.ANP) ainsi qu'un adénovirus contrôle codant pour le gène de la (3-galactosidase (Ad.betaGal). Afin d'examiner les effets de l'expression intrapulmonaire du gène de l'ANP sur l'hypertension artérielle pulmonaire les adénovirus Ad.ANP ou Ad.betaGal ont été administrés à des rats Wistars par voie intratrachéale. Le peptide a été détecté dans le liquide de lavage bronchoalvéolaire après 4 jours et jusqu'à 10-17 jours après l'administration de l'Ad.ANP (5x 10*8 DECP50): Le marquage immunohistochimique de l'ANP était localisé au niveau des cellules épithéliales pulmonaire bronchiolaires et alvéolaires. Les rats traités par l'Ad.ANP (5x10*8 DECP50) un jour avant l'exposition à l'hypoxie (15 jours, 10% O2) ont, par rapport aux rats contrôles, une pression pulmonaire moyenne (32.1+-1.93 mmHg vs 35.5+-2 mmHg, P<0.01) et un indice de fulton (0.52+-0.089 vs 0.67+-0.12, P<0.001) plus bas, ainsi qu'une hypertrophie ventriculaire droite et une muscularisation des artérioles pulmonaires distales moins sévère. Ces résultats montrent que la l'expression pulmonaire du peptide atrial natriurétique (ANP) chez les rats exposés à une hypoxie chronique atténue le développement de l'hypertension artérielle pulmonaire.MAISONS-ALFORT-Ecole Vétérin (940462302) / SudocSudocFranceF

Étude de la différenciation de cellules souches hépatiques en cellules productrices d insuline (effets de la transduction des protéines Pdx-1 ou Pdx-1-VP16 dans les lignées cellulaires WB et BMEL )

Une approche thérapeutique du diabète de type I consiste à développer des sources alternatives de cellules ß afin d en disposer en quantité non limitante en vue de leur transplantation. Du fait de l origine endodermique et de propriétés physiologiques communes avec les cellules ß, les cellules hépatiques sont des bonnes candidates. Dans ces cellules, la surexpression du gène codant pour Pdx-1, facteur clé du développement pancréatique et de la fonction ß, induit leur conversion en cellules productrices d insuline. La fusion de Pdx-1 à l activateur viral VP16 renforce cette action. Par ailleurs, la protéine Pdx-1 contient un peptide de transduction (PTD) lui permettant de traverser les membranes. L objectif de cette étude a été d évaluer les effets de la transduction des protéines Pdx-1 ou Pdx-1-VP16 sur la différenciation de deux lignées de cellules souches hépatiques, WB et BMEL, en cellules productrices d insuline. Nous avons produit les protéines Pdx-1(-VP16) et vérifié leur capacité de transduction ainsi que leur fonctionnalité. Puis, nous avons montré que les protéines Pdx-1(-VP16) couplées à un milieu riche en glucose engagent les cellules WB, mais pas les cellules BMEL, vers un phénotype pancréatique endocrine ß. Une autre approche consistant à inhiber l expression de Hes1, un facteur limitant la différenciation pancréatique endocrine exprimé par les BMEL, n a pas permis d orienter ces cellules vers un phénotype ß. Le traitement par la protéine Pdx-1 ou Pdx-1-VP16 pourrait donc constituer, sous certaines conditions, un nouvel outil pour générer des cellules productrices d insuline à partir de cellules hépatiques ainsi qu une alternative à la thérapie géniqueA new approach of type I diabetes therapy consists in developing alternative and renewable sources of transplantable ß cells. As liver and pancreas share endodermal origin and physiological properties, hepatic cells seem to be suitable candidates. Overexpression of the gene coding for Pdx-1, a key factor of pancreatic development and ß cell function, induces conversion of hepatic cells into insulin-producing cells. Fusion of Pdx-1 to the potent viral activator VP16 enhances this action. Furthermore, Pdx-1 contains a Protein Transduction Domain (PTD) enabling it to cross membranes. The aim of our study was to evaluate effects of Pdx-1 or Pdx-1-VP16 protein transduction on liver-to-ß-like cell conversion in two hepatic stem cell lines i.e. WB and BMEL cells. First, we produced Pdx-1(-VP16) recombinant proteins and checked their transduction and functionality. Then we proved that Pdx-1(-VP16) protein transduction in conjunction with high glucose culture induces ß-like cell commitment in WB cells, but not in BMEL cells. Repression of Hes1, a factor expressed in BMEL cells which hampers endocrine specification, did not direct these cells towards a pancreatic fate. In particular conditions, Pdx-1 or Pdx-1-VP16 protein treatment may be instrumental for in vitro liver-to-pancreas conversion and represents an alternative to gene therapy for ß cell engineering for cell therapy of diabetes.NANTES-BU Sciences (441092104) / SudocSudocFranceF

Use of infrared thermography to detect early alterations of peripheral perfusion: evaluation in a porcine model

International audienceThis study aimed to evaluate the variations of infrared thermography according to rapid hemodynamic changes, by measuring the peripheral skin temperature in a porcine model. Eight healthy piglets were anesthetized and exposed to different levels of arterial pressure. Thermography was performed on the left forelimb to measure carpus and elbow skin temperature and their associated gradient with the core temperature. Changes in skin temperature in response to variations of blood pressure were observed. A negative correlation between arterial pressure and temperature gradients between peripheral and core temperature and a negative correlation between cardiac index and these temperature gradients were observed. Thermography may serve as a tool to detect early changes in peripheral perfusion

Inhibition of vascular smooth muscle cell proliferation and migration in vitro and neointimal hyperplasia in vivo by adenoviral-mediated atrial natriuretic peptide delivery

Chantier qualité GAInternational audienceBackground: Vascular smooth muscle cell (VSMC) proliferation and migration are important components of the remodeling process in atherosclerosis or following angioplasty. Atrial natriuretic peptide (ANP) inhibits the growth of VSMCs in vitro but this effect has not been proven in vivo. In the present study, we examined the effects of local overexpression of ANP following gene transfer on in vitro VSMC proliferation and migration and in vivo neointimal formation in a rat carotid artery model of vascular injury. Methods: ANP gene transfer was performed using a recombinant adenovirus containing the ANP cDNA controlled by the Rous sarcoma virus (RSV) long terminal repeat (Ad-RSV-ANP). A recombinant adenovirus expressing the RSV-controlled β-galactosidase gene (Ad-RSV-β-gal) was used as the control. Rat VSMC culture was used for in vitro studies. In the in vivo experiments, carotid arteries were analyzed after balloon injury and local infusion of the viral solution. Results: VSMCs transfected by Ad-RSV-ANP produced a significant amount of ANP detected by immunoreactive assay and accumulated about 6.5 times more cGMP than the viral control. VSMC proliferation stimulated with 10% fetal calf serum was reduced by 31% and migration by 25%. Fourteen days after injury, neointimal formation and the intima/media ratio were reduced by 25% and 28%, respectively, in the Ad-RSV-ANP-treated group compared to the control group. Conclusions: The present study demonstrates the efficacy of recombinant adenovirus Ad-RSV-ANP with respect to inhibiting rat VSMC proliferation and migration. Our findings also provide evidence that ANP is implicated in the modulation of vascular remodeling following endothelial injury