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Hoffmann L.S.,University of Bonn | Larson C.J.,Drug Discovery Unit | Pfeifer A.,University of Bonn | Pfeifer A.,NRW International Graduate Research School Biotech Pharma
Handbook of Experimental Pharmacology | Year: 2015

The second messenger cyclic guanosine monophosphate (cGMP) is a key mediator in physiological processes such as vascular tone, and its essential involvement in pathways regulating metabolism has been recognized in recent years. Here, we focus on the fundamental role of cGMP in brown adipose tissue (BAT) differentiation and function. In contrast to white adipose tissue (WAT), which stores energy in the form of lipids, BAT consumes energy stored in lipids to generate heat. This so-called non-shivering thermogenesis takes place in BAT mitochondria, which express the specific uncoupling protein 1 (UCP1). The energy combusting properties of BAT render it a promising target in antiobesity strategies in which BAT could burn the surplus energy that has accumulated in obese and overweight individuals. cGMP is generated by guanylyl cyclases upon activation by nitric oxide or natriuretic peptides. It affects several downstream molecules including cGMP-receptor proteins such as cGMP-dependent protein kinase and is degraded by phosphodiesterases. The cGMP pathway contains several signaling molecules that can increase cGMP signaling, resulting in activation and recruitment of brown adipocytes, and hence can enhance the energy combusting features of BAT. In this review we highlight recent results showing the physiological significance of cGMP signaling in BAT, as well as pharmacological options targeting cGMP signaling that bear a high potential to become BAT-centered therapies for the treatment of obesity. © Springer International Publishing Switzerland 2015. Source

Dosa S.,University of Bonn | Stirnberg M.,University of Bonn | Lulsdorff V.,University of Bonn | Haussler D.,University of Bonn | And 4 more authors.
Bioorganic and Medicinal Chemistry | Year: 2012

The benzamidine moiety, a well-known arginine mimetic, has been introduced in a variety of ligands, including peptidomimetic inhibitors of trypsin-like serine proteases. According to their primary substrate specificity, the benzamidine residue interacts with the negatively charged aspartate at the bottom of the S1 pocket of such enzymes. Six series of benzamidine derivatives (1-73) were synthesized and evaluated as inhibitors of two prototype serine proteases, that is, bovine trypsin and human thrombin. As a further target, human matriptase-2, a recently discovered type II transmembrane serine protease, was investigated. Matriptase-2 represents an important regulatory protease in iron homeostasis by down-regulation of the hepcidin expression. Compounds 1-73 were designed to contain a fixed sulfamoyl benzamidine moiety as arginine mimetic and a linker-connected additional substructure, such as a tert-butyl ester, carboxylate or second benzamidine functionality. A systematic mapping approach was performed with these inhibitors to scan the active site of the three target proteases. In particular, bisbenzamidines, able to interact with both the S1 and S3/S4 binding sites, showed notable affinity. In branched bisbenzamidines 66-73 containing a third hydrophobic residue, opposite effects of the stereochemistry on trypsin and thrombin inhibition were observed. © 2012 Elsevier Ltd. All rights reserved. Source

Trueck C.,University of Bonn | Trueck C.,NRW International Graduate Research School Biotech Pharma | Zimmermann K.,University of Bonn | Zimmermann K.,NRW International Graduate Research School Biotech Pharma | And 8 more authors.
Pharmaceutical Research | Year: 2012

Purpose: Targeting of specific cells and tissues is of great interest for clinical relevant gene- and cell-based therapies. We use magnetic nanoparticles (MNPs) with a ferrimagnetic core (Fe3O4) with different coatings to optimize MNP-assisted lentiviral gene transfer with focus on different endothelial cell lines. Methods: Lentiviral vector (LV)/MNP binding was characterized for various MNPs by different methods (e.g. magnetic responsiveness measurement). Transduced cells were analyzed by flow cytometry, fluorescence microscopy and iron recovery. Cell transduction and cell positioning under physiological flow conditions were performed using different in vitro and ex vivo systems. Results: Analysis of diverse MNPs with different coatings resulted in identification of nanoparticles with improved LV association and enhanced transduction properties of complexes in several endothelial cell lines. The magnetic moments of LV/ MNP complexes are high enough to achieve local gene targeting of perfused endothelial cells. Perfusion of a mouse aorta with LV/MNP transduced cells under clinically relevant flow conditions led to local cell attachment at the intima of the vessel. Conclusion: MNP-guided lentiviral transduction of endothelial cells can be significantly enhanced and localized by using optimized MNPs. © Springer Science+Business Media, LLC 2012. Source

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