Brown adipose tissue (BAT) can increase whole-body energy expenditure (EE) and is associated with metabolic health, making it a promising pharmacologic target. In rodents, BAT activation by norepinephrine is mainly mediated by beta3-adrenergic receptor (AR) stimulation. However, recent evidence suggests that, in humans, the beta2-AR may be more important for the activation of BAT than the beta3-AR. We investigated in 12 healthy volunteers whether the specific beta2-AR agonist fenoterol activates human BAT comparable to the natural stimulus, cold exposure. Both interventions robustly increased EE, but only cold exposure activated BAT as assessed by FDG uptake. RNA sequencing (RNA-seq) analysis of human BAT revealed that the expression of beta3-AR, but not of beta2-AR, correlates with the expression of UCP1, the hallmark of thermogenic brown adipocytes. Our data indicate that the beta2-AR is not the main activating receptor of human BAT and suggest that beta2-AR agonism increases EE in tissues other than BAT.

Melanoma is a highly aggressive cancer with limited therapeutic options. In melanoma cell lines, β2AR activation leads to the suppression of pro-proliferatory MAPK/ERK signaling. This suggests that fenoterol, a potent β2AR agonist, can be useful in the treatment of melanoma. Here, we investigated the structure-activity relationship (SAR) of fenoterol derivatives for β2AR-depedent ERK suppression. We used the UACC-647 human-derived melanoma cell line to screen a panel of chiral compounds based on the fenoterol scaffold. The levels of phosphoactive ERK1/2 were quantified by immunoblotting. Anti-tumorigenic activity of the drugs was assessed using MTS assay and zebrafish xenograft model. (R,R') stereoisomers of fenoterol derivatives exhibited the highest suppression of ERK phosphorylation, followed by (R,S') and (S,R') isomers, with (S,S') isomers being the least active, mirroring trends observed in β2AR binding and cAMP accumulation. SAR analysis revealed that modifications to the α' alkyl chain and the 4'-hydroxy moieties significantly affected ERK-inhibitory activity of fenoterol derivatives. (R,R')-4'-hydroxy-1-naphthylfenoterol [(R,R')-HNF] was the most active inhibitor of ERK activation with an IC50 of 0.03 nM. However, it showed minimal anti-proliferative activity in the zebrafish xenograft model. In contrast, (R,R')-4'-methoxy-1-naphthylfenoterol [(R,R')-MNF], a weaker ERK inhibitor (IC50 = 0.17 nM), significantly reduced cell viability in vitro (IC50 = 14.07 µM) and tumor growth in vivo. SAR for fenoterol-mediated ERK inhibition in melanoma was defined, highlighting the importance of the (R,R') stereochemistry. Crucially, potent ERK inhibition does not directly predict anti-tumorigenic activity, as shown by (R,R')-HNF. The pronounced anti-proliferatory effect of (R,R')-MNF, despite weaker ERK inhibition, implies additional mechanisms beyond ERK modulation.

Aging is associated with skeletal muscle weakness and oxidative stress. Here, we hypothesized that aging may lead to alterations in adrenoceptor (AR)-dependent regulation of muscle contractility. These changes can aggravate muscle contractile dysfunction and correlate with redox disturbances. Glycolytic extensor digitorum longus (EDL) and oxidative soleus muscles from young adult (3 months), middle-aged (12 months), and old (24 months) mice were used. Contractile responses were elicited by electrical stimulation at different frequencies. During the aging process, inotropic effects of adrenaline in both muscles changed in a similar manner. Adrenaline caused a positive inotropic effect in young adult mice, then its action disappeared at middle age, and, finally, adrenaline decreased the contraction force at old age. Fenoterol, a β-AR agonist, exerted a negative inotropic action in EDL and soleus muscles of young adult and middle-aged mice. This effect of fenoterol is partially preserved in soleus (but not EDL) muscles at advanced age. In both muscles, the positive inotropy of adrenaline was blocked by β2-AR antagonist, whereas the fenoterol-mediated suppression of contraction force was inhibited by β3-AR antagonists. Immunofluorescent labeling revealed both β2- and β3-AR-positive signals at the sarcolemma. Accordingly, the age-related shift of balance from positive to negative inotropic action of adrenaline might be partially dependent on the interplay of β2- and β3-adrenergic signaling in the skeletal muscles. Despite the commonalities in the changes in adrenergic regulation of contractions in both muscles, oxidative stress, decline in antioxidant enzyme activities, and ultrastructural disturbances were much more clearly expressed in aged EDL versus soleus muscles.

Biased agonism in G protein-coupled receptors is a phenomenon resulting in the selective activation of distinct intracellular signaling pathways by different agonists, which may exhibit bias toward either Gs, Gi, or arrestin-mediated pathways. This study investigates the structural basis of ligand-induced biased agonism within the context of the β2-adrenergic receptor (β2-AR). Atomistic molecular dynamics simulations were conducted for β2-AR complexes with two stereoisomers of methoxynaphtyl fenoterol (MNFen), that is, compounds eliciting qualitatively different cellular responses. The simulations reveal distinct interaction patterns within the binding cavity, dependent on the stereoisomer. These changes propagate to the intracellular parts of the receptor, triggering various structural responses: the dynamic structure of the intracellular regions of the (R,R)-MNFen complex more closely resembles the "Gs-compatible" and "β-arrestin-compatible" conformation of β2-AR, while both stereoisomers maintain structural responses equidistant from the inactive conformation. These findings are confirmed by independent coarse-grained simulations. In the context of deciphered molecular mechanisms, Trp313 plays a pivotal role, altering its orientation upon interactions with (R,R)-MNFen, along with the Lys305-Asp192 ionic bridge. This effect, accompanied by ligand interactions with residues on TM2, increases the strength of interactions within the extracellular region and the binding cavity, resulting in a slightly more open conformation and a minor (by ca. 0.2 nm) increase in the distance between the TM5-TM7, TM1-TM6, TM6-TM7, and TM1-TM5 pairs. On the other hand, an even slighter decrease in the distance between the TM1-TM4 and TM2-TM4 pairs is observed.

Asthma and chronic obstructive pulmonary disease (COPD) are the most common diagnoses for adults and children with respiratory tract inflammation. Recently, a novel fixed dose combination consisting of Ipratropium and Fenoterol has been released for the management and control of the symptoms of such disorders. The current research has newly developed and optimized three smart, accurate, simple, cost-effective, and eco-friendly spectrophotometric methods that enabled the simultaneous determination of the drugs under study in their combined inhaler dosage form, without the need for any previous separation steps, using water as a green solvent. The strategy employed was based on calculating one or two factors as a numerical spectrum or constant, which provided the complete removal of any component in the mixture that might overlap and the mathematical filtration of the targeted analyte. The methods developed could be classified into two types of spectrophotometric windows. Window I; involved absorption spectrum in their original zero-order forms (°D), which included recently designed methods named induced concentration subtraction (ICS) and induced dual wavelength (IDW). While window III focused on the ratio spectrum as the induced amplitude modulation (IAM) method. The extremely low absorptivity and lack of distinct absorption maximum in the zero-order absorption spectrum of Ipratropium were two intrinsic challenges that were better overcome by the proposed spectrophotometric methods than by the conventionally used ones. According to ICH guidelines, the proposed methods were validated using unified regression over range 2.0-40.0 µg/mL in the ICS method, while the linearity ranges for the IDW and IAM methods were 5.0-40.0 µg/mL of Ipratropium and 2.0-40.0 µg/mL of Fenoterol. Moreover, the three proposed methods were effectively used to assay the co-formulated marketed inhaler and further expanded to confirm the delivered dose uniformity in compliance with the USP guidelines. Finally, the established methods were evaluated for their greenness and blueness, in comparison to the official and reported analysis methods, using advanced cutting edge software metrics. Furthermore, the suggested techniques adhered well to the white analytical chemistry postulates that were recently published.

Although no published data exist on the use of metaproterenol by mouth or inhaler during lactation, data from the related drug, terbutaline, indicate that very little is expected to be excreted into breastmilk.[1] The authors of several reviews and an expert panel agree that use of inhaled bronchodilators is acceptable during breastfeeding because of the low bioavailability and maternal serum levels after use.[2-5]

In this study, fluorescence recovery after photobleaching (FRAP) experiments were performed on RBC labeled by lipophilic fluorescent dye CM-DiI to evaluate the role of adenylyl cyclase cascade activation in changes of lateral diffusion of erythrocytes membrane lipids. Stimulation of adrenergic receptors with epinephrine (adrenaline) or metaproterenol led to the significant acceleration of the FRAP recovery, thus indicating an elevated membrane fluidity. The effect of the stimulation of protein kinase A with membrane-permeable analog of cAMP followed the same trend but was less significant. The observed effects are assumed to be driven by increased mobility of phospholipids resulting from the weakened interaction between the intermembrane proteins and RBC cytoskeleton due to activation of adenylyl cyclase signaling cascade.

The behavior of a molecule within its environment is governed by chemical fields present in 3D space. However, beyond local descriptors in 3D, the conformations a molecule assumes, and the resulting clusters also play a role in influencing structure-activity models. This study focuses on the clustering of atoms according to the vector space of four atoms aligned in the Z-Matrix Reference system for molecular similarity. Using 3D-QSAR analysis, it was aimed to determine the pharmacophore groups as interaction points in the binding region of the β2-adrenoceptor target of fenoterol stereoisomers. Different types of local reactive descriptors of ligands have been used to elucidate points of interaction with the target. Activity values for ligand-receptor interaction energy were determined using the Levenberg-Marquardt algorithm. Using the Molecular Comparative Electron Topology method, the 3D pharmacophore model (3D-PhaM) was obtained after aligning and superimposing the molecules and was further validated by the molecular docking method. Best guesses were calculated with a non-output validation (LOO-CV) method. Finally, the data were calculated using the 'graphic fingerprint' technique. Based on the eLKlopman (Electrostatic LUMO Klopman) descriptor, the Q[2] value of this derivative set was calculated as 0.981 and the R[2]ext value is calculated as 0.998.

Cranberry offers numerous cardiovascular benefits. According to several studies, this fruit promotes the oxidation of low-density lipoprotein, enhances high-density lipoprotein, reduces platelet coagulation, and improves vascular activity. Albino male rats were divided into five groups (n = 5 per group). The control group received intraperitoneal administration of normal saline. The second group was injected with metaproterenol (MET) 3 days a week for 4 weeks. The third, fourth, and fifth groups were given cranberry extract in doses of 75, 100, and 150, respectively, along with heart-damaging drugs. Blood samples were collected and sent to the laboratory on the fourth weekend and 1 week after completing the injections in the fourth week (the sixth weekend) for analyzing serum factors such as cardiac creatine kinase MB, cardiac troponin I (cTnI), and aspartate aminotransferase (AST). The serum activity of the cardiac evaluation parameters in the fourth week demonstrated a highly significant correlation among the groups with respect to AST and cTnI (p < .001). Additionally, a significant relationship was observed between AST and cTnI within the target groups (p < .05). Ultimately, the findings indicated that the consumption of cranberry extract, due to its impact on heart function, could effectively modify serum indicators associated with heart damage. The utilized extract also exhibited efficacy, albeit with variable effects. Therefore, it is recommended to use cranberry extract synergistically with other chemical and herbal medications to achieve more sustained effects.

β-adrenergic receptors (βARs) belong to a key molecular targets that regulate the most important processes occurring in the human organism. Although over the last decades a zebrafish model has been developed as a model complementary to rodents in biomedical research, the role of β2AR in regulation of pathological and toxicological effects remains to elucidate. Therefore, the study aimed to clarify the role of β2AR with a particular emphasis on the distinct role of subtypes A and B of zebrafish β2AR. As model compounds selective β2AR agonists - (R,R)-fenoterol ((R,R)-Fen) and its new derivatives: (R,R)-4'-methoxyfenoterol ((R,R)-MFen) and (R,R)-4'-methoxy-1-naphtylfenoterol ((R,R)-MNFen) - were tested. We described dose-dependent changes observed after fenoterols exposure in terms of general toxicity, cardiotoxicity and neurobehavioural responses. Subsequently, to better characterise the role of β2-adrenergic stimulation in zebrafish, we have performed a series of molecular docking simulations. Our results indicate that (R,R)-Fen displays the highest affinity for subtype A of zebrafish β2AR and β2AAR might be involved in pigment depletion. (R,R)-MFen shows the lowest affinity for zebrafish β2ARs out of the tested fenoterols and this might be associated with its cardiotoxic and anxiogenic effects. (R,R)-MNFen displays the highest affinity for subtype B of zebrafish β2AR and modulation of this receptor might be associated with the development of malformations, increases locomotor activity and induces a negative chronotropic effect. Taken together, the presented data offer insights into the functional responses of the zebrafish β2ARs confirming their intraspecies conservation, and support the translation of the zebrafish model in pharmacological and toxicological research.

We recently showed that a minimally-invasive removal of MDA-MB-231HM primary tumors (PTs) and elimination of their secreted factors (including IL-6, IL-8, VEGF, EGF, PDGF-aa, MIF, SerpinE1, and M-CSF), caused regression of spontaneous micro-metastases into a non-growing dormant state. To explore the underlying mechanisms and potential clinical ramifications of this phenomenon, we herein used the MDA-MB-231HM human breast cancer cell-line, in-vitro, and in vivo following orthotopic implantation in immune-deficient BALB/C nu/nu mice. Employing bioluminescence imaging, we found that adding laparotomy to minimally-invasive removal of the PT caused an outbreak of micro-metastases. However, perioperative β-adrenergic and COX-2 inhibition, using propranolol + etodolac, maintained metastatic dormancy following laparotomy. In-vitro, β-adrenergic agonists (epinephrine or metaproterenol) and prostaglandin-E2 markedly increased MDA-MB-231HM secretion of the pro-metastatic factors IL-6, IL-8, and VEGF, whereas cortisol reduced their secretion, effects that were maintained even 12 h after the washout of these agonists. In-vivo, laparotomy elevated IL-6 and IL-8 levels in both plasma and ex-vivo PT spontaneous secretion, whereas perioperative propranolol + etodolac administration blocked these effects. Similar trends were evident for EGF and MIF. Promoter-based bioinformatics analyses of excised PT transcriptomes implicated elevated NF-kB activity and reduced IRF1 activity in the gene regulatory effects of laparotomy, and these effects were inhibited by pre-surgical propranolol + etodolac. Taken together, our findings suggest a novel mechanism of post-operative metastatic outbreak, where surgery-induced adrenergic and prostanoid signaling increase the secretion of pro-metastatic factors, including IL-6, IL-8, and VEGF, from PT and possibly residual malignant tissue, and thereby prevent residual disease from entering dormancy.