Investigation of Antidepressant Properties of Yohimbine by Employing Structure-Based Computational Assessments

The use of pharmaceuticals to treat Major Depressive Disorder (MDD) has several drawbacks, including severe side effects. Natural compounds with great efficacy and few side effects are in high demand due to the global rise in MDD and ineffective treatment. Yohimbine, a natural compound, has been used to treat various ailments, including neurological conditions, since ancient times. Serotonergic neurotransmission plays a crucial role in the pathogenesis of depression; thus, serotonergic receptor agonist/antagonistic drugs are promising anti-depressants. Yohimbine was investigated in this study to determine its antidepressant activity using molecular docking and pharmacokinetic analyses. Additionally, the in silico mutational study was carried out to understand the increase in therapeutic efficiency using site-directed mutagenesis. Conformational changes and fluctuations occurring during wild type and mutant serotonergic receptor, 5-hydroxytryptamine receptors 1A (5HT1A) and yohimbine were assessed by molecular dynamics MD simulation studies. Yohimbine was found to satisfy all the parameters for drug-likeness and pharmacokinetics analysis. It was found to possess a good dock score and hydrogen-bond interactions with wild type 5HT1A structure. Our findings elaborate the substantial efficacy of yohimbine against MDD; however, further bench work studies may be carried out to prove the same.

Network Pharmacology and Metabolomics Studies on Antimigraine Mechanisms of Da Chuan Xiong Fang (DCXF)

Background. Da Chuan Xiong Fang (DCXF) is a traditional Chinese medicine (TCM) formula used to treat migraines. Previously, we uncovered partial mechanisms involved in the therapeutic actions of DCXF on migraines. Methods. In this study, we further elucidated its antimigraine mechanisms in vivo by using an integrated strategy coupling with network pharmacology and metabolomics techniques. Results. Network pharmacology identified 33 genes linked with both migraine and DCXF, most of which were 5-hydroxytryptamine receptors, dopamine, and peptide receptors. The results of GO and KEGG enrichment analysis showed that DCXF significantly regulated tyrosine metabolism, tryptophan metabolism, dopamine metabolic process, glucose transmembrane transport, lipid metabolism, and fatty acid transport. The results of metabolomics analysis found that the metabolism of tryptophan and tyrosine in the brain tissue and energy and lipid metabolism of rats tended towards normal and reached normal levels after administering DCXF. The metabolomics and network pharmacology approaches demonstrated similar antimigraine effects of DCXF on endogenous neurotransmitters and overall trends in serum and brain tissue. Using both approaches, 62 hub genes were identified from the protein-protein interaction (PPI) network of DCXF and gene-metabolite interaction network, with hub genes and different metabolites in serum and brain tissue. The hub genes of DCXF, which were mostly linked with inflammation, might affect mainly neurotransmitters in serum and brain tissue metabolisms. Conclusion. Network pharmacology and metabolomics study may help identify hub genes, metabolites, and possible pathways of disease and treatment. Additionally, two parts of the results were integrated to confirm each other. Their combination may help elucidate the relationship between hub genes and metabolites and provide the further understanding of TCM mechanisms.

Coevolution underlies GPCR-G protein selectivity and functionality

G protein-coupled receptors (GPCRs) regulate diverse physiological events, which makes them as the major targets for many approved drugs. G proteins are downstream molecules that receive signals from GPCRs and trigger cell responses. The GPCR-G protein selectivity mechanism on how they properly and timely interact is still unclear. Here, we analyzed model GPCRs (i.e. HTR, DAR) and Gα proteins with a coevolutionary tool, statistical coupling analysis. The results suggested that 5-hydroxytryptamine receptors and dopamine receptors have common conserved and coevolved residues. The Gα protein also have conserved and coevolved residues. These coevolved residues were implicated in the molecular functions of the analyzed proteins. We also found specific coevolving pairs related to the selectivity between GPCR and G protein were identified. We propose that these results would contribute to better understandings of not only the functional residues of GPCRs and Gα proteins but also GPCR-G protein selectivity mechanisms.

Heterodimerization with 5-HT 2B R Is Indispensable for β 2 AR-mediated Cardioprotection

Rationale: The β 2 -adrenoceptor (β 2 -AR), a prototypical G protein-coupled receptor (GPCR), couples to both G s and G i proteins. Stimulation of theβ 2 -AR is beneficial to humans and animals with heart failure presumably because it activates the downstream G i -PI3K-Akt cell survival pathway. Cardiac β 2 -AR signaling can be regulated by crosstalk or heterodimerization with other GPCRs, but the physiological and pathophysiological significance of this type of regulation has not been sufficiently demonstrated. Objective: Here, we aim to investigate the potential cardioprotective effect of β 2 -adrenergic stimulation with a subtype-selective agonist, (R,R')-4-methoxy-1-naphthylfenoterol (MNF), and to decipher the underlying mechanism with a particular emphasis on the role of heterodimerization of β 2 -ARs with another GPCR, 5-hydroxytryptamine receptors 2B (5-HT 2B Rs). Methods and Results: Using pharmacological, genetic and biophysical protein-protein interaction approaches, we studied the cardioprotective effect of the β 2 -agonist, MNF, and explored the underlying mechanism in both in vivo in mice and cultured rodent cardiomyocytes insulted with doxorubicin (Dox), hydrogen peroxide (H 2 O 2 ) or ischemia/reperfusion. In Dox-treated mice, MNF reduced mortality and body weight loss, while improving cardiac function and cardiomyocyte viability. MNF also alleviated myocardial ischemia/reperfusion injury. In cultured rodent cardiomyocytes, MNF inhibited DNA damage and cell death caused by Dox, H 2 O 2 or hypoxia/reoxygenation. Mechanistically, we found that MNF or another β 2 -agonist zinterol markedly promoted heterodimerization of β 2 -ARs with 5-HT 2B Rs. Upregulation of the heterodimerized 5-HT 2B Rs and β 2 -ARs enhanced β 2 -AR-stimulated Gi-Akt signaling and cardioprotection while knockdown or pharmacological inhibition of the 5-HT attenuated β 2 -AR-stimulated G i signaling and cardioprotection. Conclusions: These data demonstrate that the β 2 -AR-stimulated cardioprotective Gi signaling depends on the heterodimerization of β 2 -ARs and 5-HT 2B Rs.

5-Hydroxytryptamine receptors (version 2019.4) in the IUPHAR/BPS Guide to Pharmacology Database

5-HT receptors (nomenclature as agreed by the NC-IUPHAR Subcommittee on 5-HT receptors [194] and subsequently revised [176]) are, with the exception of the ionotropic 5-HT3 class, GPCRs where the endogenous agonist is 5-hydroxytryptamine. The diversity of metabotropic 5-HT receptors is increased by alternative splicing that produces isoforms of the 5-HT2A (non-functional), 5-HT2C (non-functional), 5-HT4, 5-HT6 (non-functional) and 5-HT7 receptors. Unique amongst the GPCRs, RNA editing produces 5-HT2C receptor isoforms that differ in function, such as efficiency and specificity of coupling to Gq/11 and also pharmacology [40, 482]. Most 5-HT receptors (except 5-ht1e and 5-ht5b) play specific roles mediating functional responses in different tissues (reviewed by [463, 382]).