Role of Tyr356(7.43) and Ser190(4.57) in Antagonist Binding in the Rat β1-Adrenergic Receptor

Multitargeting in cardioprotection: An example of biaromatic compounds

A multitarget drug design approach is actively developing in modern medicinal chemistry and pharmacology, especially with regard to multifactorial diseases such as cardiovascular diseases, cancer, and neurodegenerative diseases. A detailed study of many well-known drugs developed within the single-target approach also often reveals additional mechanisms of their real pharmacological action. One of the multitarget drug design approaches can be the identification of the basic pharmacophore models corresponding to a wide range of the required target ligands. Among such models in the group of cardioprotectors is the linked biaromatic system. This review develops the concept of a "basic pharmacophore" using the biaromatic pharmacophore of cardioprotectors as an example. It presents an analysis of possible biological targets for compounds corresponding to the biaromatic pharmacophore and an analysis of the spectrum of biological targets for the five most known and most studied cardioprotective drugs corresponding to this model, and their involvement in the biological effects of these drugs.

Norepinephrine Protects against Methamphetamine Toxicity through β2-Adrenergic Receptors Promoting LC3 Compartmentalization

Norepinephrine (NE) neurons and extracellular NE exert some protective effects against a variety of insults, including methamphetamine (Meth)-induced cell damage. The intimate mechanism of protection remains difficult to be analyzed in vivo. In fact, this may occur directly on target neurons or as the indirect consequence of NE-induced alterations in the activity of trans-synaptic loops. Therefore, to elude neuronal networks, which may contribute to these effects in vivo, the present study investigates whether NE still protects when directly applied to Meth-treated PC12 cells. Meth was selected based on its detrimental effects along various specific brain areas. The study shows that NE directly protects in vitro against Meth-induced cell damage. The present study indicates that such an effect fully depends on the activation of plasma membrane β2-adrenergic receptors (ARs). Evidence indicates that β2-ARs activation restores autophagy, which is impaired by Meth administration. This occurs via restoration of the autophagy flux and, as assessed by ultrastructural morphometry, by preventing the dissipation of microtubule-associated protein 1 light chain 3 (LC3) from autophagy vacuoles to the cytosol, which is produced instead during Meth toxicity. These findings may have an impact in a variety of degenerative conditions characterized by NE deficiency along with autophagy impairment.

Discovery of novel potent and selective ligands for 5-HT2A receptor with quinazoline scaffold

A series of compounds with quinazoline scaffold were designed, synthesized and evaluated as novel potent 5-HT2A receptor ligands. N-(4-Chlorophenyl)-2-(piperazin-1-yl)quinazolin-4-amine (5o) has a Ki value of 14.04 ± 0.21 nM, with a selectivity more than 10,000 fold over 5-HT1A receptors (D1 and D2-like receptors). The functional assay showed that this compound is an antagonist to 5-HT2A receptor with an IC50 value of 1.66 μM.

Recent structural advances of β1 and β2 adrenoceptors yield keys for ligand recognition and drug design

Because they represent attractive drug targets, adrenoceptors have been widely studied. Recent progress in structural data of β-adrenoceptors allows us to understand and predict key interactions in ligand recognition and receptor activation. Nevertheless, an important aspect of this process has only begun to be explored: the stabilization of a conformational state of these receptors upon contact with a ligand and the capacity of a ligand to influence receptor conformation through allosteric modulation, biased signaling, and selectivity. The aim of the present Perspective is to identify the well-defined orthosteric binding site and possible allosteric sites and to analyze the importance of the ligand-receptor interaction in the stabilization of certain receptor conformations. For this purpose, we have reviewed recent advances made through the use of X-ray data from ligand-β-adrenoceptor (including ADRB1 and ADRB2) crystal structures. Most importantly, implications in the medicinal chemistry field are explored in relation to drug design.

Potential modes of interaction of 9-aminomethyl-9,10-dihydroanthracene (AMDA) derivatives with the 5-HT2A receptor: a ligand structure-affinity relationship, receptor mutagenesis and receptor modeling investigation

The effects of 3-position substitution of 9-aminomethyl-9,10-dihydroanthracene (AMDA) on 5-HT 2A receptor affinity were determined and compared to a parallel series of DOB-like 1-(2,5-dimethoxyphenyl)-2-aminopropanes substituted at the 4-position. The results were interpreted within the context of 5-HT 2A receptor models that suggest that members of the DOB-like series can bind to the receptor in two distinct modes that correlate with the compounds' functional activity. Automated ligand docking and molecular dynamics suggest that all of the AMDA derivatives, the parent of which is a 5-HT 2A antagonist, bind in a fashion analogous to that for the sterically demanding antagonist DOB-like compounds. The failure of the F340 (6.52)L mutation to adversely affect the affinity of AMDA and the 3-bromo derivative is consistent with the proposed modes of orientation. Evaluation of ligand-receptor complex models suggest that a valine/threonine exchange between the 5-HT 2A and D 2 receptors may be the origin of selectivity for AMDA and two substituted derivatives.

Conformational thermostabilization of the beta1-adrenergic receptor in a detergent-resistant form

There are approximately 350 non-odorant G protein-coupled receptors (GPCRs) encoded by the human genome, many of which are predicted to be potential therapeutic targets, but there are only two structures available to represent the whole of the family. We hypothesized that improving the detergent stability of these receptors and simultaneously locking them into one preferred conformation will greatly improve the chances of crystallization. We developed a generic strategy for the isolation of detergent-solubilized thermostable mutants of a GPCR, the beta1-adrenergic receptor. The most stable mutant receptor, betaAR-m23, contained six point mutations that led to an apparent T(m) 21 degrees C higher than the native protein, and, in the presence of bound antagonist, betaAR-m23 was as stable as bovine rhodopsin. In addition, betaAR-m23 was significantly more stable in a wide range of detergents ideal for crystallization and was preferentially in an antagonist conformation in the absence of ligand.