Pleiotrophin regulates lung epithelial cell proliferation and differentiation during fetal lung development via {beta}-catenin and Dlk1.

Pleiotrophin regulates lung epithelial cell proliferation and differentiation during fetal lung development via {beta}-catenin and Dlk1.: "

Pleiotrophin regulates lung epithelial cell proliferation and differentiation during fetal lung development via {beta}-catenin and Dlk1.

J Biol Chem. 2009 Aug 6;

Authors: Weng T, Gao L, Bhaskaran M, Guo Y, Gou D, Narayanaperumal J, Chintagari NR, Zhang K, Liu L

The role of pleiotrophin in fetal lung development was investigated. We found that pleiotrophin and its receptor, protein tyrosine phosphatase receptor beta/zeta, were highly expressed in mesenchymal and epithelial cells of the fetal lungs, respectively. Using isolated fetal alveolar epithelial type II cells, we demonstrated that pleiotrophin promoted fetal type II cell proliferation and arrested type II cell trans-differentiation into alveolar epithelial type I cells. Pleiotrophin also increased wound healing of injured type II cell monolayer. Knock-down of pleiotrophin influenced lung branching morphogenesis in a fetal lung organ culture model. Pleiotrophin increased the tyrosine phosphorylation of beta-catenin, promoted beta-catenin translocation into the nucleus and activated TCF/LEF transcription factors. Dlk1, a membrane ligand that initiates the Notch signaling pathway, was identified as a down-stream target of the pleiotrophin/beta-catenin pathway by endogenous dlk1 expression, promoter assay and chromatin immunoprecipitation. These results provide evidence that pleiotrophin regulates fetal type II cell proliferation and differentiation via integration of multiple signaling pathways including pleiotrophin, beta-catenin and Notch pathways.

Notch1 upregulates LPS-induced macrophage activation by increasing NF-kappaB activity.

Notch1 upregulates LPS-induced macrophage activation by increasing NF-kappaB activity.: "

Notch1 upregulates LPS-induced macrophage activation by increasing NF-kappaB activity.

Eur J Immunol. 2009 Aug 6;

Authors: Monsalve E, Ruiz-García A, Baladrón V, Ruiz-Hidalgo MJ, Sánchez-Solana B, Rivero S, García-Ramírez JJ, Rubio A, Laborda J, Díaz-Guerra MJ

Macrophages present different Notch receptors and ligands on their surface. Following macrophage activation by LPS or other TLR ligands, Notch1 expression is upregulated. We report here that Notch signaling increases both basal and LPS-induced NF-kappaB activation, favoring the expression of genes implicated in the inflammatory response, such as the cytokines TNF-alpha and IL-6, or enzymes, such as iNOS. Delta4 seems to be the most effective ligand to induce Notch activation and increasing NF-kappaB transcriptional activity in macrophages. We show that Notch1 signaling promotes NF-kappaB translocation to the nucleus and DNA binding by increasing both phosphorylation of the IkappaB kinase alpha/beta complex and the expression of some NF-kappaB family members. Treatment of macrophages with the gamma-secretase inhibitor DAPT, which prevents the cleavage and activation of Notch receptors, inhibits all these processes, diminishing NF-kappaB activity following LPS stimulation. Additionally, we show that the active intracellular Notch fragment can directly interact with TNF-alpha and iNOS promoters. Our results suggest that Notch signaling results in an amplification of the macrophage-dependent inflammatory response by enhancing NF-kappaB signaling.

Selective inhibition of embryonic development in starfish by long-chain alkyl derivatives of UMP, TMP and AMP.

Selective inhibition of embryonic development in starfish by long-chain alkyl derivatives of UMP, TMP and AMP.

Tanaka T, Ogita A, Usuki Y, Fujita KI.

Nat Prod Res. 2009 Aug 6:1-7

Nucleoside analogs have been evaluated as useful tools for the investigation of the mechanism of cell differentiation. We thus examined the effects of nucleoside 5'-alkylphosphates (1-10) on the morphogenetic development of starfish embryos. These nucleotide derivatives were all permissive for their development up to the blastula stage, but the derivatives with lauryl side chain selectively inhibited one of the following stages into bipinnaria larvae. Among them, uridine 5'-laurylphosphate (2) inhibited gastrulation of the blastula, as is the case with the antibiotic tunicamycin, suggesting its inhibitory activity on sulfated and non-sulfated glycoprotein syntheses. Unexpectedly, adenosine 5'-laurylphosphate (8) was evaluated as a novel class of inhibitor that can arrest the embryos exactly at the late gastrula stage, absolutely inhibiting cell differentiation involved in the development of gastrointestinal tract. This is the first report on the appearance of biological activity due to the structural modification of a naturally-occurring molecule, which is critical to the morphogenetic development of multicellular organisms.

Nina Jablonski: reason to celebrate

Or, Darwin was wrong! :-)

Evita dear, pense à tes vitamines ma belle :-*

Technorati Tags: evolution, Darwin

Bio-éthique: Les écologies et leurs dérives

Bio-éthique: Les écologies et leurs dérives

Le problème est que je n'ai pas été étonné des attaques contre Vasella comme Samia l'a été. J'ai souvenir, de longue date, des marquages dont a été victime une de mes anciennes boss quand le labo a été équipé d'une animalerie moderne pour le confort des animaux : bagnole rayée, tags sur les murs de sa maison. Rien de grave, que du très agaçant.

Mais c'était en France et il y a presque 25 ans… Pas étonnant qu'aux USA et de nos jours ça aille plus loin. Il est heureux qu'ils n'en sont pas à tirer sur les gens parce que Dame Nature leur a parlé dans leur tête. Ca va venir, des allumés il y en a partout.

Il est toujours intéressant de jauger les gens par leurs réactions. Il y a quelques jours il y a eu l'annonce de l'utilisation de C. elegans pour les tests antibiotiques dont l'étude de toxicité nécessite un eucaryote multicellulaire. Deux types de réactions autour de moi, les uns ravis qu'un nouveau test diminue les besoins de test sur les rongeurs, un premier tri étant fait chez C. elegans. Une de mes voisines, écologiste/végétarienne et pet-être membre des PETA (je la soupçonne mais nous n'en avons pas discuté de ça, je ménage ma pression artérielle) a eu une réaction amusante : "vous n'arrêterez jamais vous les scientifiques tant que vous n'aurez pas torturé tous les animaux de Gaïa". Gaïa prononcé avec un G très majuscule.

Nous avons eu une discussion courte qui l'a énervée suffisamment pour quitter la terrasse du café sans avoir fini son thé du matin, ce qui ne lui ressemble pas. C'est peut-être parce que je lui ai dit qu'elle rentrait plein pot dans ma catégorie neuneux/nunuches. Et qu'elle voulait éviter de me balancer le restant de son thé à la figure (elle semblait en avoir une envie folle)

La présentation de Bernard Baertschi que Samia nous propose est très intéressante et fait réfléchir. Il faudrait peut-être faire un arbre phylogénique des diverses philosophies écologiques.

maming the gragon

Crocoduck on sapiens on dino…

Flying Snakes... and Leaping Lizards