TY  - THES
A1  - Chen, Wen
T1  - Functional Role of NFATc1 in the Control of Life and Death of Lymphocytes
T1  - Die funktionelle Rolle von NFATc1 in der Kontrolle von Leben und Tod von Lymphozyten
N2  - In this study, murine ES cells and DT40 B cells were used in parallel to disrupt the Nfatc1 gene and to study the function of individual 6 Nfatc1 isoforms, especially the function of highly inducible NFATc1/aA.We found that the short isoform NFATc1/aA protects DT40 B cells against apoptosis while the long isoform NFATc1/aC appears to enforce apoptosis. DNA microarray studies have shown that in NFATc1" DT40 B cells expressing ectopically human NFATc1/aA, the pkc-theta gene is several fold stronger expressed as in wild type cells. Our results of EMSA (Electrophoretic Mobility Shift Assays) and ChIP (chromatin immuno-precipitation) experiments demonstrated the binding of NFATc1/aA to the pkc-theta promoter in vitro and in vivo. NF-kappa B was also found to bind to the NFATc1 P1-promoter in vitro and in vivo. These data suggest and further prove that NF-kappa B contributes to the induction of the NFATc1 P1 promoter upon activation of T cells. So, NFATc1/aA and NF-kappa B were found to cross-talk in the transcriptional upregulation of their target genes, such as the IL-2 gene and the Nfatc1 gene itself, at multiple steps upon induction of apoptosis. While the pro-apoptotic mechanism of NFATc1s long isoform(s) remains unclear, its corresponding “death partners” are worth further studies. The elucidation of functional roles of NFATc1s short or long isoforms in the control of apoptosis of lymphocytes helps to understand apoptosis regulation, and thereby, the fate of lymphocytes.
N2  - In der vorliegenden Studie wurden ES Zellen von der Maus und DT40 B Zellen vom Huhn verwendet, um paralell das Nfatc1 auszuknocken und die Rolle der einzelnen 6 Nfatc1 Isoformen zu studieren, insbesorndere die Funktion des stark induzierbaren NFATc1/aA.Wir konnten feststellen, daß die kurze Isoform NFATc1/aA" DT40 B Zellen gegen Apoptose schützt, während die lange Isoform NFATc1/aC scheinbar die Apoptose verstärkt. DNA Microarray Studien haben gezeigt, daß NFATc1-/-/aA DT40 B Zellen, die humanes NFATc1/aA ektopisch exprimieren, das pkc-theta Gen deutlich stärker exprimieren als in Wildtyp Zellen. Unsere Ergebnisse von EMSA und ChIP Experimenten demonstrieren die Bindung von NFATc1/aA an den pkc-theta Promoter in vitro und in vivo. Für NF-kappa B wurde eine Bindung am Nfatc1 P1 Promoter in vitro und in vivo gezeigt. Dies lässt vermuten, daß NF-kappa B eine Rolle bei der Induktion am Nfatc1 P1 Promoter nach der Aktivierung der T Zelle spielt.Es wurde herausgefunden, daß nach Induktion der Apoptose, NFATc1/aA und NF-kappa B „cross-talk“ an unterschiedlichen Stellen in der transkriptionellen Hochregulierung ihrer Zielgene, wie z.b. dem IL-2 Gen und dem Nfatc1 Gen selbst. Weil die pro-apoptotischen Mechanismen der lange(n) Isoform(en) von NFATc1 unklar bleiben, sollten die korrespondierenden „death partners“ in weiteren Studien untersucht werden. Eine Klärung der funktionellen Rollen der NFATc1 Isoformen in der Kontrolle der Apotose in Lymphozyten wird helfen,die Regulation der Apotose, und damit auch das Schicksal der Lymphozyten, zu verstehen.
KW  - Lymphozyten
KW  - NFATc1
KW  - Apoptosis
KW  - lymphocyte
KW  - NFATc1
KW  - apoptosis
Y1  - 2007
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-26675
ER  - 
TY  - JOUR
A1  - Chen, Wen
A1  - Gaßner, Birgit
A1  - Börner, Sebastian
A1  - Nikolaev, Viacheslav O.
A1  - Schlegel, Nicolas
A1  - Waschke, Jens
A1  - Steinbronn, Nadine
A1  - Strasser, Ruth
A1  - Kuhn, Michaela
T1  - Atrial natriuretic peptide enhances microvascular albumin permeability by the caveolae-mediated transcellular pathway
JF  - Cardiovascular Research
N2  - Aims 
Cardiac atrial natriuretic peptide (ANP) participates in the maintenance of arterial blood pressure and intravascular volume homeostasis. The hypovolaemic effects of ANP result from coordinated actions in the kidney and systemic microcirculation. Hence, ANP, via its guanylyl cyclase-A (GC-A) receptor and intracellular cyclic GMP as second messenger, stimulates endothelial albumin permeability. Ultimately, this leads to a shift of plasma fluid into interstitial pools. Here we studied the role of caveolae-mediated transendothelial albumin transport in the hyperpermeability effects of ANP.
Methods and results 
Intravital microscopy studies of the mouse cremaster microcirculation showed that ANP stimulates the extravasation of fluorescent albumin from post-capillary venules and causes arteriolar vasodilatation. The hyperpermeability effect was prevented in mice with conditional, endothelial deletion of GC-A (EC GC-A KO) or with deleted caveolin-1 (cav-1), the caveolae scaffold protein. In contrast, the vasodilating effect was preserved. Concomitantly, the acute hypovolaemic action of ANP was abolished in EC GC-A KO and Cav-1−/− mice. In cultured microvascular rat fat pad and mouse lung endothelial cells, ANP stimulated uptake and transendothelial transport of fluorescent albumin without altering endothelial electrical resistance. The stimulatory effect on albumin uptake was prevented in GC-A- or cav-1-deficient pulmonary endothelia. Finally, preparation of caveolin-enriched lipid rafts from mouse lung and western blotting showed that GC-A and cGMP-dependent protein kinase I partly co-localize with Cav-1 in caveolae microdomains.
Conclusion 
ANP enhances transendothelial caveolae-mediated albumin transport via its GC-A receptor. This ANP-mediated cross-talk between the heart and the microcirculation is critically involved in the regulation of intravascular volume.
KW  - caveolin-1
KW  - microvessel permeability
KW  - atrial natriuretic peptide
Y1  - 2012
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-126562
N1  - Lizenzhinweis: The online version of this article has been published under an open access model. Users are entitled to use, reproduce, disseminate, or display the open access version of this article for noncommercial purposes provided that the original authorship is properly and fully attributed; the Journal, Learned Society and Oxford University Press are attributed as the original place of publication with correct citation details given; if an article is subsequently reproduced or disseminated not in its entirety but only in part or as a derivative work this must be clearly indicated.
VL  - 93
IS  - 1
ER  -