Astemizole Derivatives as Fluorescent Probes for hERG Potassium Channel Imaging

NBD-Based Environment-Sensitive Fluorescent Probes for the Human Ether-a-Go-Go-Related Gene Potassium Channel

Three environment-sensitive probes were developed for the hERG channel based on the nitrobenzoxadiazole fluorophore herein. After careful evaluation, probes M1 and M3 were found to have a high affinity for imaging the hERG channel in the cell-based experiment. Compared with other fluorescent labeling technologies (such as fluorescent proteins), these probes afford a convenient and economical method to determine hERG channel in vitro and in cellulo. Therefore, these probes are expected to be applicable for usage in physiological and pathological studies of hERG channels and have the potential to establish a screening system for hERG channels.

Visualizing TRPA1 in the Plasma Membrane for Rapidly Screening Optical Control Agonists via a Photochromic Ligand Based Fluorescent Probe

Fluorescent probes have been used as effective methods for profiling proteins in biological systems because of their high selectivity, sensitivity, and temporal-spatial resolution. A specific fluorescent probe for understanding the function of the transient receptor potential ankyrin 1 (TRPA1) channel that is closely related with various diseases like persistent pain, respiratory, and chronic itch syndromes, however, is still lacking. Here, we report a "turn-on" fluorescent probe (A1CA) for visualizing TRPA1 channels in the plasma membrane of live cells based on a photochromic ligand derived from 4-(phenylazo)benzenamine. Evaluating the specificity and sensitivity of A1CA by electrophysiology and confocal imaging showed that the A1CA probe displays higher affinity and selectivity to TRPA1 channel versus all other ion channels including TRPV1, TRPV3, Nav1.4, Nav1.5, and hERG. Based on the supporting evidence, A1CA has great potential as a molecular imaging probe for high-throughput screening of novel TRPA1 agonists.

The visualization of hERG channels in living cells via a fluorescent probe regulated by the synergy between solvatochromism and molecular rotation based on simple targeting of the group 4-benzylaniline

A highly sensitive fluorescent probe CBH based on solvatochromism and molecular rotation was designed and developed for imaging of hERG channels by employing a novel targeting group 4-benzylaniline. More importantly, CBH has the potential for the quantitative analysis of the hERG channels expressed in tumor cells.

Astemizole-based turn-on fluorescent probes for imaging hERG potassium channel

Based on the scaffold of astemizole, three novel turn-on fluorescent probes (N1-N3) for human ether-a-go-go-related gene (hERG) potassium channel were developed herein. These probes have reasonable fluorescence properties, acceptable cell toxicity, and potent inhibitory activity, all of which contribute to cell imaging at the nanomolar level. Overall, these probes have the potential for setting up a screening system for hERG channels.

Aggregation-Induced Emission: Lighting Up hERG Potassium Channel

Based on the scaffold of astemizole and E-4031, four AIE light-up probes (L1-L4) for Human Ether-a-go-go-Related Gene (hERG) potassium channel were developed herein using AIE fluorogen(TPE). These probes showing advantages such as low background interference, superior photostability, acceptable cell toxicity, and potent inhibitory activity, which could be used to image hERG channels at the nanomolar level. These AIE light-up probes hoped to provide guidelines for the design of more advanced AIE sensing and imaging hERG channels to a broad range of applications.

3D-SDAR modeling of hERG potassium channel affinity: A case study in model design and toxicophore identification

A dataset of 237 human Ether-à-go-go Related Gene (hERG) potassium channel inhibitors (180 of which were used for model building and validation, whereas 57 constituted the "true" external prediction set) collected from 22 literature sources was modeled by 3D-SDAR. To produce reliable and reproducible classification models for hERG blocking, the initial set of 180 chemicals was split into two subsets: a balanced modeling set consisting of 118 compounds and an unbalanced validation set comprised of 62 compounds. A PLS bagging-like algorithm written in Matlab was used to process the data and assign each compound to one of the two (hERG+ or hERG-) activity classes. The best predictive model evaluated on the basis of a fully randomized hold-out test set (comprising 20% of the modeling set) used 4 latent variables and a grid of 6ppm×6ppm×1Å in the C-C region, 6ppm×30ppm×1Å in the C-N region, and 30ppm×30ppm×1Å in the N-N region. An overall accuracy of 0.84 was obtained for both the hold-out test set and the validation set. Further, an external prediction set consisting of 57 drugs and drug derivatives was used to estimate the true predictive power of the reported 3D-SDAR model - a slight reduction of the overall accuracy down to 0.77 was observed. 3D-SDAR map of the most frequently occurring bins and their projection on the standard coordinate space of the chemical structures allowed identification of a three-center toxicophore composed of two aromatic rings and an amino group. A U test along the distance axis of the most frequently occurring 3D-SDAR bins was used to set the distance limits of the toxicophore. This toxicophore was found to be similar to an earlier reported phospholipidosis (PLD) toxicophore.

3-D structural interactions and quantitative structural toxicity studies of tyrosine derivatives intended for safe potent inflammation treatment

Background

Drugs that inhibit cyclooxygenase-2 (COX-2) while sparing cyclooxygenase-1 (COX-1) represent a new attractive therapeutic development and offer new perspective for further use of COX-2 inhibitors. Intention of this work is to develop safer, selective COX-2 inhibitors that do not produce harmful effects.

Results

A series of 55 tyrosine derivatives were designed for evaluation as selective COX-2 inhibitors and investigated by in silico for their anti-inflammatory activities using C-Docker. The results of docking study showed that 35 molecules were found to selectively inhibit the enzyme COX-2. These molecules formed stable π hydrophobic and additional van der Waals interactions in the active site side pocket of COX-2. The molecules selected from docking studies were examined through ADMET descriptors and Osiris property explorer to find its safety profile as well. The tyrosine derivatives containing toxic fragments were eliminated.

Conclusion

The results conclude that out of 55, 19 molecules possessed best binding energy (< −3.333 kcal/mol) and these molecules had more selective and safer COX-2 inhibitor profile compared to the standard celecoxib.Graphical abstract