Sympathetic neurons are generated through a succession of differentiation steps that initially lead to noradrenergic neurons innervating different peripheral target tissues. Specific targets, like sweat glands in rodent footpads, induce a change from noradrenergic to cholinergic transmitter phenotype. Here, we show that cytokines acting through the gp130 receptor are present in sweat glands. Selective elimination of the gp130 receptor in sympathetic neurons prevents the acquisition of cholinergic and peptidergic features (VAChT, ChT1, VIP) without affecting other properties of sweat gland innervation. The vast majority of cholinergic neurons in the stellate ganglion, generated postnatally, are absent in gp130-deficient mice. These results demonstrate an essential role of gp130-signaling in the target-dependent specification of the cholinergic neurotransmitter phenotype.

The basic helix-loop-helix transcription factor Hand2 is essential for the proliferation and noradrenergic differentiation of sympathetic neuron precursors during development. Here we address the function of Hand2 in postmitotic, differentiated sympathetic neurons. Knockdown of endogenous Hand2 in cultured E12 chick sympathetic neurons by siRNA results in a significant (about 60%) decrease in the expression of the noradrenergic marker genes dopamine-β-hydroxylase (DBH) and tyrosine hydroxylase (TH). In contrast, expression of the pan-neuronal genes TuJ1, HuC and SCG10 was not affected. To analyze the in vivo role of Hand2 in differentiated sympathetic neurons we used mice harboring a conditional Hand2-null allele and excised the gene by expression of Cre recombinase under control of the DBH promotor. Mouse embryos homozygous for Hand2 gene deletion showed decreased sympathetic neuron number and TH expression was strongly reduced in the residual neuron population. The in vitro Hand2 knockdown also enhances the CNTF-induced expression of the cholinergic marker genes vesicular acetylcholine transporter (VAChT) and choline acetyltransferase (ChAT). Taken together, these findings demonstrate that the Hand2 transcription factor plays a key role in maintaining noradrenergic properties in differentiated neurons.

The neuronal protein 25 (NP25), a member of the calponin (CaP) protein family, has previously been identified as neuron-specific protein in the adult rat brain. Here, we show an early onset of NP25 expression in the chick embryo neural tube. NP25 represents, together with NeuroM, one of the earliest markers for postmitotic neurons. To elucidate its function in the developing nervous system, NP25 was overexpressed in E5 and E9 sensory neurons, E7 sympathetic neurons and PC12 cells that show different endogenous NP25 expression levels. Whereas E5 and E9 sensory neurons and PC12 cells, which express low endogenous levels of NP25, responded by enhanced neurite outgrowth, a reduction of neurite length was observed in sympathetic neurons, which already express high endogenous levels of NP25. Knockdown of NP25 in sensory neurons using NP25 siRNA resulted in shorter neurites, whereas reduction of NP25 expression in sympathetic neurons led to increased neurite length. These results suggest a dynamic function for NP25 in the regulation of neurite growth, with an optimal level of NP25 required for maximal growth.

Human mesenchymal stem cells (hMSCs) represent a promising treatment approach for tissue repair and regeneration. However, little is known about the underlying mechanisms and the fate of the transplanted cells. The objective of the presented work was to determine the feasibility of PET imaging and in vivo monitoring after transplantation of dopamine type 2 receptor-expressing cells. Methods: An hMSC line constitutively expressing a mutant of the dopamine type 2 receptor (D2R80A) was generated by lentiviral gene transfer. D2R80A messenger RNA expression was confirmed by reverse transcriptase-polymerase chain reaction. Localization of the transmembrane protein was analyzed by confocal fluorescence microscopy. The stem cell character of transduced hMSCs was investigated by adipogenic and osteogenic differentiation. Migration capacity was assessed by scratch assays in time-lapse imaging. In vitro specific binding of ligands was tested by fluorescenceactivated cell sorting analysis and by radioligand assay using 18 Ffallypride. Imaging of D2R80A overexpressing hMSC transplanted into athymic rats was performed by PET using 18 F-fallypride. Results: hMSCs showed long-term overexpression of D2R80A. As expected, the fluorescence signal suggested the primary localization of the protein in the membrane of the transduced cells. hMSC and D2R80A retained their stem cell character demonstrated by their osteogenic and adipogenic differentiation capacity and their proliferation and migration behavior. For in vitro hMSCs, at least 90% expressed the D2R80A transgene and hMSC-D2R80A showed specific binding of 18 F-fallypride. In vivo, a specific signal was detected at the transplantation site up to 7 d by PET. Conclusion: The mutant of the dopamine type 2 receptor (D2R80A) is a potent reporter to detect hMSCs by PET in vivo.

Ziel: Die Studie beschreibt Hintergründe akuter Alkoholintoxikationen unter Jugendlichen und evaluiert die gemeindezentrierte Kombination indizierter und selektiver Präventionsmaßnahmen. </p><p> Methodik: Eine Inanspruchnahmepopulation intoxizierter Jugendlicher (n = 188) wird in wesentlichen Merkmalen beschrieben. Die Analyse der Interventionseffekte vergleicht Trenddaten der Jahre 2001–2006 zu Jahresprävalenzen akuter Intoxikationen (n = 1.805 Fälle) für die Projektregion (n = 26.490 Personen, Alter 10–18 Jahre) und die Vergleichsregion (n = 84.331). </p><p> Ergebnisse: Risiken für akute Intoxikationen betreffen Herkunft aus Ein-Elter-Familien, Integration in eine Alkohol konsumierende Freundesgruppe, wahllosen Alkoholkonsum und die Belastung mit psychiatrischen Symptomen. Für die Zeit des Projektes wurden unterschiedliche Trends für die Interventions- und Vergleichsregion ermittelt. Während in der Interventionsregion die Jahresprävalenz der Intoxikationen um 20 % sank, stieg sie in der Vergleichsregion um 33 %. </p><p> Schlussfolgerung: Akut intoxizierte Jugendliche entstammen überzufällig häufig Risikopopulationen. Gemeindezentrierte Präventionsmaßnahmen sind mit dem Rückgang von Jahresprävalenzen akuter Intoxikationen unter Jugendlichen assoziiert.