Functional Characterization of the Obesity-Linked Variant of the β3-Adrenergic Receptor

Adrenergic receptor β3 (ADRβ3) is a member of the rhodopsin-like G protein-coupled receptor family. The binding of the ligand to ADRβ3 activates adenylate cyclase and increases cAMP in the cells. ADRβ3 is highly expressed in white and brown adipocytes and controls key regulatory pathways of lipid metabolism. Trp64Arg (W64R) polymorphism in the ADRβ3 is associated with the early development of type 2 diabetes mellitus, lower resting metabolic rate, abdominal obesity, and insulin resistance. It is unclear how the substitution of W64R affects the functioning of ADRβ3. This study was initiated to functionally characterize this obesity-linked variant of ADRβ3. We evaluated in detail the expression, subcellular distribution, and post-activation behavior of the WT and W64R ADRβ3 using single cell quantitative fluorescence microscopy. When expressed in HEK 293 cells, ADRβ3 shows a typical distribution displayed by other GPCRs with a predominant localization at the cell surface. Unlike adrenergic receptor β2 (ADRβ2), agonist-induced desensitization of ADRβ3 does not involve loss of cell surface expression. WT and W64R variant of ADRβ3 displayed comparable biochemical properties, and there was no significant impact of the substitution of tryptophan with arginine on the expression, cellular distribution, signaling, and post-activation behavior of ADRβ3. The obesity-linked W64R variant of ADRβ3 is indistinguishable from the WT ADRβ3 in terms of expression, cellular distribution, signaling, and post-activation behavior.

Functional Characterization of the obesity-linked variant of the β3-adrenergic receptor

Adrenergic receptor β3 (ADRβ3) is a member of the rhodopsin-like G protein-coupled receptor family. The binding of the ligand to ADRβ3 activates adenylate cyclase and increases cAMP in the cells. ADRβ3 is highly expressed in white and brown adipocytes and controls key regulatory pathways of lipid metabolism. Trp64Arg (W64R) polymorphism in the ADRβ3 has been associated with the early development of type 2 diabetes mellitus, lower resting metabolic rate, abdominal obesity, and insulin resistance. It is unclear how the substitution of W64R affects the functioning of ADRβ3. This study was initiated to functionally characterize this obesity-linked variant of ADRβ3. We evaluated in detail the expression, subcellular distribution, and post-activation behavior of the WT and W64R ADRβ3 using a single cell quantitative fluorescence microscopy. When expressed in HEK 293 cells, ADRβ3 shows a typical distribution displayed by other GPCRs with a predominant localization at the cell surface. Unlike Adrenergic receptor β2 (ADRβ2), agonist induced desensitization of ADRβ3 does not involve loss of cell surface expression. WT and W64R variant of ADRβ3 displayed comparable biochemical properties and there was no significant impact of the substitution of Tryptophan with Arginine on the expression, cellular distribution, signaling, and post-activation behavior of ADRβ3. The obesity-linked W64R variant of ADRβ3 is indistinguishable from the WT ADRβ3 in terms of expression, cellular distribution, signaling, and post-activation behavior.

Reactive Oxygen Species (ROS)-Sensitive Prodrugs of the Tyrosine Kinase Inhibitor Crizotinib

Tyrosine kinase inhibitors revolutionized cancer therapy but still evoke strong adverse effects that can dramatically reduce patients’ quality of life. One possibility to enhance drug safety is the exploitation of prodrug strategies to selectively activate a drug inside the tumor tissue. In this study, we designed a prodrug strategy for the approved c-MET, ALK, and ROS1 tyrosine kinase inhibitor crizotinib. Therefore, a boronic-acid trigger moiety was attached to the 2-aminopyridine group of crizotinib, which is a crucial position for target kinase binding. The influence of the modifications on the c-MET- and ALK-binding ability was investigated by docking studies, and the strongly reduced interactions could be confirmed by cell-free kinase inhibition assay. Furthermore, the newly synthesized compounds were tested for their activation behavior with H2O2 and their stability in cell culture medium and serum. Finally, the biological activity of the prodrugs was investigated in three cancer cell lines and revealed a good correlation between activity and intrinsic H2O2 levels of the cells for prodrug A. Furthermore, the activity of this prodrug was distinctly reduced in a non-malignant, c-MET expressing human lung fibroblast (HLF) cell line.

Does Information on Automated Driving Functions and the Way of Presenting It before Activation Influence Users’ Behavior and Perception of the System?

Information on automated driving functions when automation is not activated but is available have not been investigated thus far. As the possibility of conducting non-driving related activities (NDRAs) is one of the most important aspects when it comes to perceived usefulness of automated cars and many NDRAs are time-dependent, users should know the period for which automation is available, even when not activated. This article presents a study (N = 33) investigating the effects of displaying the availability duration before—versus after—activation of the automation on users’ activation behavior and on how the system is rated. Furthermore, the way of addressing users regarding the availability on a more personal level to establish “sympathy” with the system was examined with regard to acceptance, usability, and workload. Results show that displaying the availability duration before activating the automation reduces the frequency of activations when no NDRA is executable within the automated drive. Moreover, acceptance and usability were higher and workload was reduced as a result of this information being provided. No effects were found with regard to how the user was addressed.