TY  - JOUR
A1  - Drube, Sebastian
A1  - Weber, Franziska
A1  - Loschinski, Romy
A1  - Beyer, Mandy
A1  - Rothe, Mandy
A1  - Rabenhorst, Anja
A1  - Göpfert, Christiane
A1  - Meininger, Isabel
A1  - Diamanti, Michaela A.
A1  - Stegner, David
A1  - Häfner, Norman
A1  - Böttcher, Martin
A1  - Reinecke, Kirstin
A1  - Herdegen, Thomas
A1  - Greten, Florian R.
A1  - Nieswandt, Bernhard
A1  - Hartmann, Karin
A1  - Krämer, Oliver H.
A1  - Kamradt, Thomas
T1  - Subthreshold IKK activation modulates the effector functions of primary mast cells and allows specific targeting of transformed mast cells
JF  - Oncotarget
N2  - Mast cell differentiation and proliferation depends on IL-3. IL-3 induces the activation of MAP-kinases and STATs and consequently induces proliferation and survival. Dysregulation of IL-3 signaling pathways also contribute to inflammation and tumorigenesis. We show here that IL-3 induces a SFK- and Ca2\(^{+}\)-dependent activation of the inhibitor of κB kinases 2 (IKK2) which results in mast cell proliferation and survival but does not induce IκBα-degradation and NFκB activation. Therefore we propose the term "subthreshold IKK activation". This subthreshold IKK activation also primes mast cells for enhanced responsiveness to IL-33R signaling. Consequently, co-stimulation with IL-3 and IL-33 increases IKK activation and massively enhances cytokine production induced by IL-33. We further reveal that in neoplastic mast cells expressing constitutively active Ras, subthreshold IKK activation is associated with uncontrolled proliferation. Consequently, pharmacological IKK inhibition reduces tumor growth selectively by inducing apoptosis in vivo. Together, subthreshold IKK activation is crucial to mediate the full IL-33-induced effector functions in primary mast cells and to mediate uncontrolled proliferation of neoplastic mast cells. Thus, IKK2 is a new molecularly defined target structure.
KW  - mast cells
KW  - subthreshold IKK activation
KW  - mitogenic signaling
KW  - NFκB-activation
Y1  - 2015
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-143681
VL  - 6
IS  - 7
ER  - 
TY  - JOUR
A1  - Popp, Michael
A1  - Thielman, Ina
A1  - Nieswandt, Bernhard
A1  - Stegner, David
T1  - Normal Platelet Integrin Function in Mice Lacking Hydrogen Peroxide-Induced Clone-5 (Hic-5)
JF  - PLoS One
N2  - Integrin αIIbβ3 plays a central role in the adhesion and aggregation of platelets and thus is essential for hemostasis and thrombosis. Integrin activation requires the transmission of a signal from the small cytoplasmic tails of the α or β subunit to the large extracellular domains resulting in conformational changes of the extracellular domains to enable ligand binding. Hydrogen peroxide-inducible clone-5 (Hic-5), a member of the paxillin family, serves as a focal adhesion adaptor protein associated with αIIbβ3 at its cytoplasmic tails. Previous studies suggested Hic-5 as a novel regulator of integrin αIIbβ3 activation and platelet aggregation in mice. To assess this in more detail, we generated Hic-5-null mice and analyzed activation and aggregation of their platelets in vitro and in vivo. Surprisingly, lack of Hic-5 had no detectable effect on platelet integrin activation and function in vitro and in vivo under all tested conditions. These results indicate that Hic-5 is dispensable for integrin αIIbβ3 activation and consequently for arterial thrombosis and hemostasis in mice.
KW  - platelet activation
KW  - fibrinogen
KW  - integrins
KW  - platelets
KW  - thrombin
KW  - flow cytometry
KW  - platelet aggregation
KW  - blood
Y1  - 2015
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-125724
VL  - 10
IS  - 7
ER  - 
TY  - JOUR
A1  - Ammar, Mohamed Raafet
A1  - Thahouly, Tamou
A1  - Hanauer, André
A1  - Stegner, David
A1  - Nieswandt, Bernhard
A1  - Vitale, Nicolas
T1  - PLD1 participates in BDNF-induced signalling in cortical neurons
JF  - Scientific Reports
N2  - The brain-derived neurotrophic factor BDNF plays a critical role in neuronal development and the induction of L-LTP at glutamatergic synapses in several brain regions. However, the cellular and molecular mechanisms underlying these BDNF effects have not been firmly established. Using in vitro cultures of cortical neurons from knockout mice for Pld1 and Rsk2, BDNF was observed to induce a rapid RSK2-dependent activation of PLD and to stimulate BDNF ERK1/2-CREB and mTor-S6K signalling pathways, but these effects were greatly reduced in Pld1\(^{-/-}\) neurons. Furthermore, phospho-CREB did not accumulate in the nucleus, whereas overexpression of PLD1 amplified the BDNF-dependent nuclear recruitment of phospho-ERK1/2 and phospho-CREB. This BDNF retrograde signalling was prevented in cells silenced for the scaffolding protein PEA15, a protein which complexes with PLD1, ERK1/2, and RSK2 after BDNF treatment. Finally PLD1, ERK1/2, and RSK2 partially colocalized on endosomal structures, suggesting that these proteins are part of the molecular module responsible for BDNF signalling in cortical neurons.
KW  - phospholipase D
KW  - ERK map kinease
KW  - long-term potentation
KW  - brain
KW  - protein RSK2
KW  - dendritic growth
KW  - neurite outgrowth
KW  - neurotrophic factor
KW  - coffin-lowry-syndrome
KW  - phosphatidic acid
Y1  - 2015
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-139962
VL  - 5
IS  - 14778
ER  -