Search Results (12)

Engineered light-sensitive molecules offer a sophisticated toolkit for the manipulation of biological systems with both spatial and temporal precision. Notably, artificial “caged” compounds can activate specific receptors solely in response to light exposure. However, the uncaging process can lead to the formation of potentially harmful byproducts. For example, the photochemical release of adrenaline (epinephrine) is accompanied by the formation of adrenochrome, which has neuro- and cardiotoxic effects. To investigate this effect in detail, we synthesized and compared two “caged” epinephrine analogs. The first was a classical compound featuring an ortho-nitrobenzyl protecting group attached to the amino group of epinephrine. The second analog retained the ortho-nitrobenzyl group but included an additional carbamate linker. The photolysis of both compounds was conducted under identical conditions, and the resulting products were analyzed using UV–Vis spectroscopy, chromatography, and NMR techniques. Surprisingly, while the classical compound led to the formation of adrenochrome, the carbamate-type caged epinephrine did not produce this byproduct, resulting in the clean release of the active substance. Subsequently, we assessed the novel compound in an in vitro platelet activation assay. The results demonstrated that the uncaging of epinephrine significantly enhances platelet activation, making it a valuable tool for advanced signaling studies. Full article

Inflammation is a tightly regulated process involving immune receptor recognition, immune cell migration, inflammatory mediator secretion, and pathogen elimination, all essential for combating infection and restoring damaged tissue. However, excessive inflammatory responses drive various human diseases. The autonomic nervous system (ANS) is known to regulate inflammatory responses; however, the detailed mechanisms underlying this regulation remain incompletely understood. Herein, we aimed to study the anti-inflammatory effects and mechanism of action of the ANS in RAW264.7 cells. Quantitative PCR and immunoblotting assays were used to assess lipopolysaccharide (LPS)-induced tumor necrosis factor α (TNFα) expression. The anti-inflammatory effects of catecholamines (adrenaline, noradrenaline, and dopamine) and acetylcholine were examined in LPS-treated cells to identify the receptors involved. Catecholamines inhibited LPS-induced TNFα expression by activating the β2 adrenergic receptor (β2-AR). β2-AR activation in turn downregulated the expression of Toll-like receptor 4 (TLR4) by stimulating protein kinase A (PKA) phosphorylation, resulting in the suppression of TNFα levels. Collectively, our findings reveal a novel mechanism underlying the inhibitory effect of catecholamines on LPS-induced inflammatory responses, whereby β2-AR activation and PKA phosphorylation downregulate TLR4 expression in macrophages. These findings could provide valuable insights for the treatment of inflammatory diseases and anti-inflammatory drug development. Full article

Training has a significant effect on the physiology of blood coagulation in humans and in horses. Several hemostatic changes have been reported after exercise in the horse but data available are inconclusive. The aim of this study was to investigate platelet activation and primary platelet-related hemostasis modifications in young never-trained Thoroughbreds in the first incremental training period in order to improve knowledge on this topic. Twenty-nine clinically healthy, untrained, 2-year-old Thoroughbred racehorses were followed during their incremental 4-month sprint exercise training. Blood collection was performed once a month, five times in total (T-30, T0, T30, T60, and T90). Platelet aggregation was measured by light transmission aggregometry in response to various agonists: adenosine diphosphate (ADP), collagen, and calcium ionophore A23187. Platelet function was evaluated using a platelet function analyzer (PFA-100^®) using collagen/ADP and collagen/adrenaline cartridges. Nitrite-nitrate (NOx) plasma concentrations were measured via a colorimetric assay to assess in vivo nitric oxide bioavailability. Platelet activation was also investigated through gene expression analyses (selectin P-SELP, ectonucleotidase CD39-ENTPD1, prostaglandin I2 synthase-PTGIS, endothelial nitric oxide synthase 3-NOS3). Differences among the time points were analyzed and mean ± SEM were calculated. Significant modifications were identified compared with T-30, with an increase in platelet aggregation (collagen:32.6 ± 4.8 vs. 21.6 ± 4.9%; ADP: 35.5 ± 2.0 vs. 24.5 ± 3.1%; A23187: 30 ± 4.7 vs. 23.8 ± 4%) and a shorter closure time of C-ADP cartridges (75.6 ± 4.4 vs. 87.7 ± 3.4 s) that tended to return to the baseline value at T90. NOx concentrations in plasma significantly increased after 30 days of the training program compared with the baseline. The first long-term training period seems to induce platelet hyperactivity after 30 days in never-trained Thoroughbreds. Regular physical training reduces the negative effects of acute efforts on platelet activation. Full article

Nitroxides, stable synthetic free radicals, are promising antioxidants, showing many beneficial effects both at the cellular level and in animal studies. However, the cells are usually treated with high millimolar concentrations of nitroxides which are not relevant to the concentrations that could be attained in vivo. This paper aimed to examine the effects of low (≤10 μM) concentrations of three nitroxides, 2,2,6,6-tetramethylpiperidin-1-oxyl (TEMPO), 4-hydroxy-TEMPO (TEMPOL) and 4-amino-TEMPO (TEMPAMINE), in pure chemical systems and on SH-SY5Y cells transfected with the human tau protein (TAU cells), a model of chronic cellular oxidative stress, and transfected with the empty plasmid (EP cells). All nitroxides were active in antioxidant-activity tests except for the 2,2′-azinobis-(3-ethylbenzthiazolin-6-sulfonate) radical (ABTS^•) decolorization assay and reduced Fe³⁺, inhibited autoxidation of adrenalin and pyrogallol and oxidation of dihydrorhodamine123 by 3-morpholino-sydnonimine SIN-1. TEMPO protected against fluorescein bleaching from hypochlorite, but TEMPAMINE enhanced the bleaching. Nitroxides showed no cytotoxicity and were reduced by the cells to non-paramagnetic derivatives. They decreased the level of reactive oxygen species, depleted glutathione, and increased mitochondrial-membrane potential in both types of cells, and increased lipid peroxidation in TAU cells. These results demonstrate that even at low micromolar concentrations nitroxides can affect the cellular redox equilibrium and other biochemical parameters. Full article

In this work, attention is focused on the non-essential amino acid L-Tyrosine (TYR) hydroxylated to L-DOPA, which is the precursor to the neurotransmitters dopamine, noradrenaline (norepinephrine; NE) and adrenaline (epinephrine; EP) known as catecholamines and their interactions with redox-active Cu(II). Catecholamines have multiple functions in biological systems, including the regulation of the central nervous system, and free (unbound) redox metal ions are present in many diseases with disturbed metal homeostasis. The interaction between catecholamines and Cu(II) has been studied by means of Electron Paramagnetic Resonance spectroscopy (EPR), EPR spin trapping and UV-vis spectroscopy. The obtained spectroscopic results are supported by Density Functional Theory calculations. Only minor qualitative and quantitative changes in the UV-vis spectra of all the studied compounds have been observed following their interactions with Cu(II) ions. The low-temperature EPR spectra were more convincing and confirmed the interaction between Cu(II) ions and all the studied compounds, involving hydroxyl groups and amino nitrogens. The use of an ABTS assay revealed that the compounds under study possessed radical-scavenging activities against ABTS^•+ in the order TYR < EP < DA < NE~L-DOPA. The neurotransmitters DA, NE and EP, following their interaction with Cu(II), exhibit the ability to (partially) reduce Cu(II) to Cu(I) species which was confirmed using the Cu(I) specific chelator neocuproine. EPR spin-trapping experiments revealed the suppressed formation of hydroxyl radicals (^•OH) in a copper(II) catalyzed Fenton-like system in the presence of catecholamines. Only in the case of EP was autooxidation in a stock solution observed. Furthermore, the oxidation of EP is enhanced in the presence of Cu(II) ions. In conclusion, it has been confirmed that the oxidation of catecholamines in the presence of copper promotes the redox cycling process, resulting in the formation of ROS, which may, in turn, cause damage to neuronal systems. Full article

Neurological disorders are disorders characterized by progressive loss of neurons leading to disability. Neurotransmitters such as nor-adrenaline, dopamine, and serotonin are partially regulated by the enzyme monoamine oxidase (MAO). Treatments for conditions like Alzheimer’s, Parkinson’s, anxiety, and depression involve the use of MAOIs. To target MAO enzyme inhibition, various scaffolds are prepared and evaluated, including modified coumarins, chromone carboxylic acid substituents, pyridazine derivatives, and indolylmethylamine. The research presented here focuses on combining different computational tools to find new inhibitors of the MAO-B protein. We discovered 5 possible chemical inhibitors using the above computational techniques. We found five molecular inhibitors with high binding affinity using computational methods. These five molecules showed a high binding affinity; they are −10.917, −10.154, −10.223, −10.858, and −9.629 Kcal/mol, respectively. Additionally, the selected inhibitors were further examined by in vitro activity, and their binding affinity was confirmed using an enzyme-based assay. In summary, the computational studies performed here using molecular dynamics and free energy calculations can also be used to design and predict highly potent derivatives as MAO-B inhibitors, and these top inhibitors help in the development of novel drugs for neurological diseases such as Alzheimer’s and Parkinson’s. Full article

Cardiovascular diseases remain one of the leading causes of death worldwide. Unfortunately, the available pharmacotherapeutic options have limited effectiveness. Therefore, developing new drug candidates remains very important. We selected six novel arylpiperazine alkyl derivatives of salicylamide to investigate their cardiovascular effects. Having in mind the beneficial role of α₁-adrenergic receptors in restoring sinus rhythm and regulating blood pressure, first, using radioligand binding assays, we evaluated the affinity of the tested compounds for α-adrenergic receptors. Our experiments revealed their high to moderate affinity for α₁- but not α₂-adrenoceptors. Next, we aimed to determine the antiarrhythmic potential of novel derivatives in rat models of arrhythmia induced by adrenaline, calcium chloride, or aconitine. All compounds showed potent prophylactic antiarrhythmic activity in the adrenaline-induced arrhythmia model and no effects in calcium chloride- or aconitine-induced arrhythmias. Moreover, the tested compounds demonstrated therapeutic antiarrhythmic activity, restoring a normal sinus rhythm immediately after the administration of the arrhythmogen adrenaline. Notably, none of the tested derivatives affected the normal electrocardiogram (ECG) parameters in rodents, which excludes their proarrhythmic potential. Finally, all tested compounds decreased blood pressure in normotensive rats and reversed the pressor response to methoxamine, suggesting that their hypotensive mechanism of action is connected with the blockade of α₁-adrenoceptors. Our results confirm the antiarrhythmic and hypotensive activities of novel arylpiperazine derivatives and encourage their further investigation as model structures for potential drugs. Full article

Human performance enhancing drugs (PEDs), frequently used in sport competitions, are strictly prohibited by the World Anti-Doping Agency (WADA). Biological samples collected from athletes and regular patients are continuously tested regarding the identification and/or quantification of the banned substances. Current work is focused on the application of a new analytical method, molecularly imprinted nanoparticles (nanoMIPs), to detect and determine concentrations of certain prohibited drugs, such as β-blockers, in water and human urine samples. These medications are used in the treatment of cardiovascular conditions, negative effects of adrenaline (helping to relief stress), and hypertension (slowing down the pulse and softening the arteries). They can also significantly increase muscle relaxation and improve heart efficiency. The new method of the detection and quantification of β-blockers is based on synthesis, characterization, and implementation of nanoMIPs (so-called plastic antibodies). It offers numerous advantages over the traditional methods, including high binding capacity, affinity, and selectivity for target molecules. Additionally, the whole process is less complicated, cheaper, and better controlled. The size and shape of the nanoMIPs is evaluated by dynamic light scattering (DLS) and transmission electron microscope (TEM). The affinity and selectivity of the nanoparticles are investigated by competitive pseudo enzyme-linked immunosorbent assay (pseudo-ELISA) similar to common immunoassays employing natural antibodies. To provide reliable results towards either doping detection or therapeutic monitoring using the minimal invasive method, the qualitative and quantitative analysis of these drugs is performed in water and human urine samples. It is demonstrated that the assay can detect β-blockers in water within the linear range 1 nmol·L⁻¹–1 mmol·L⁻¹ for atenolol with the detection limit 50.6 ng mL⁻¹, and the linear range 1 mmol·L⁻¹–10 mmol·L⁻¹ for labetalol with the detection limit of 90.5 ng·mL⁻¹. In human urine samples, the linear range is recorded in the concentration range 0.1 mmol·L⁻¹–10 nmol·L⁻¹ for atenolol and 1 mmol·L⁻¹–10 nmol·L⁻¹ for labetalol with a detection limit of 61.0 ng·mL−1 for atenolol and 99.4 ng·mL⁻¹ for labetalol. Full article

Alzheimer’s disease (AD) is a neurodegenerative disease characterized by memory impairment in patients. Erythropoietin (EPO) has been reported to stimulate neurogenesis. This study was conducted to determine the regenerative effects of EPO in an AD model and to assess its underlying mechanism. Recombinant human EPO was intraperitoneally administered to AD mice induced by intracerebroventricular Aβ oligomer injection. Behavioral assessments with novel object recognition test and passive avoidance task showed improvement in memory function of the EPO-treated AD mice compared to that of the saline-treated AD mice (p < 0.0001). An in vivo protein assay for the hippocampus and cortex tissue indicated that EPO treatment modulated neurotransmitters, including dopamine, serotonin, and adrenaline. EPO treatment also restored the activity of serotonin receptors, including 5-HT4R, 5-HT7R, and 5-HT1aR (p < 0.01), at mRNA levels. Furthermore, EPO seemed to exert an anti-inflammatory influence by downregulating TLR4 at mRNA and protein levels (p < 0.05). Finally, an immunohistochemical assay revealed increments of Nestin(+) and NeuN(+) neuronal cells in the CA3 region in the EPO-treated AD mice compared to those in the saline-treated AD mice. The conclusion is that EPO administration might be therapeutic for AD by activating the serotonergic pathway, anti-inflammatory action, and neurogenic characteristics. Full article

Nanozymes are nanomaterials which exhibit artificial enzymatic activities and are considered as alternatives to natural enzymes. They are characterized by good catalytic activity and high stability, as well as ease and low cost of preparation. In this study, the mimetics of laccase or “nanolaccases” (NLacs) were synthesized by a simple method of chemical reduction of transition metal salts. The NLacs were tested for their catalytic activity in solution and on the electrode surface. The most effective NLacs, namely nAuCePt and nPtFe, were found to possess excellent laccase-like activities capable of oxidizing the endocrine hormone adrenaline (AD). These NLacs were characterized in detail and used for the development of amperometric sensors for AD determination. The amperometric sensors containing the best NLacs, as well as a natural fungal laccase, were constructed. The most effective nAuCePt-containing sensor had good specificity in relation to AD and improved analytical characteristics. It possessed a 384-fold higher sensitivity than adrenaline (230,137 A·M⁻¹·m⁻²), a 64-fold lower limit of detection (0.025 µM), and a broader linear range (0.085–45 µM) in comparison with the sensor based on natural laccase. The constructed nAuCePt-containing sensor was successfully used for AD analysis in pharmaceutical formulation. Full article

Biogenic amines, such as adrenaline, noradrenaline, histamine, dopamine, and serotonin are important neurotransmitters that also regulate cell viability. Their detection and analysis are helpful in the diagnosis of many diseases, including cancer. The aim of this study was to determine the expression profile of the biogenic amine-related genes and proteins in endometrioid endometrial cancer compared to the control group. The material consisted of endometrial tissue samples and whole blood collected from 30 endometrioid endometrial cancer patients and 30 cancer-free patients. The gene expression was determined by the mRNA microarrays and validated by qRT-PCR. Protein levels were determined in the serum by the enzyme-linked immunosorbent assay (ELISA). Overexpression of histamine H1–H3 receptors and early growth response 1 and silencing of calmodulin, the histamine H4 receptor, and the dopamine D5 receptor have been reported in endometrioid endometrial cancer. The obtained results indicate disturbances in the signaling activated by histamine and dopamine receptors, which could potentially contribute to the progression of endometrioid endometrial cancer. Full article

Serotonin is an important monoamine in the human body, playing crucial roles, such as a neurotransmitter in the central nervous system. Previously, our group reported that β-adrenergic drugs (ICI 118,551, isoprenaline, and propranolol) influence the proliferation of breast cancer cells (MCF-7 cells) and their inherent production of adrenaline. Thus, we aimed to investigate the production of serotonin in MCF-7 cells, clarifying if there is a relationship between this production and the viability of the cells. To address this question, briefly, we treated the MCF-7 cells with ICI 118,551, isoprenaline, and propranolol, and evaluated cellular viability and serotonin production by using MTT, Sulforhodamine B (SRB) and Neutral Red (NR) assays, and HPLC-ECD analysis, respectively. Our results demonstrate that isoprenaline promotes the most pronounced endogenous synthesis of serotonin, about 3.5-fold greater than control cells. Propranolol treatment also increased the synthesis of serotonin (when compared to control). On the other hand, treatment with the drug ICI 118,551 promoted a lower endogenous synthesis of serotonin, about 1.1-fold less than what was observed in the control. Together, these results reveal that MCF-7 cells can produce serotonin, and the drugs propranolol, isoprenaline and ICI 118,551 influence this endogenous production. For the first time, after modulation of the β-adrenergic system, a pronounced cellular growth can be related to higher consumption of serotonin by the cells, resulting in decreased levels of serotonin in cell media, indicative of the importance of serotonin in the growth of MCF-7 cells. Full article