The structural analogue of apelin-12 prevents energy disorders in the heart in experimental type 1 diabetes mellitus.

Type 1 diabetes mellitus (T1DM) is the most severe form of diabetes, which is characterized by absolute insulin deficiency induced by the destruction of pancreatic beta cells. The aim of this study was to evaluate the effect of a structural analogue of apelin-12 ((NαMe)Arg-Pro-Arg-Leu-Ser-His-Lys-Gly-Pro-Nle-Pro-Phe-OH, metilin) on hyperglycemia, mitochondrial (MCh) respiration in permeabilized cardiac left ventricular (LV) fibers, the myocardial energy state, and cardiomyocyte membranes damage in a model of streptozotocin (STZ) diabetes in rats. Metilin was prepared by solid-phase synthesis using the Fmoc strategy and purified using HPLC.

Properties and Activity of Peptide Derivatives of ACE2 Cellular Receptor and Their Interaction with SARS-CoV-2 S Protein Receptor-Binding Domain.

The aim of this work was to design and characterize peptides based on the α-helices h1 and h2 of the ACE2 receptor, forming the interaction interface between the receptor-binding domain (RBD) of the SARS-CoV-2 S protein and the cellular ACE2 receptor. Monomeric and heterodimeric peptides connected by disulfide bonds at different positions were synthesized. Solubility, RBD-binding affinity, and peptide helicity were experimentally measured, and molecular dynamics simulation was performed in various solvents.

Chimeric Agonist of Galanin Receptor GALR2 Reduces Heart Damage in Rats with Streptozotocin-Induced Diabetes.

Neuropeptide galanin and its N-terminal fragments reduce the generation of reactive oxygen species and normalize metabolic and antioxidant states of myocardium in experimental cardiomyopathy and ischemia/reperfusion injury. The aim of this study was to elucidate the effect of WTLNSAGYLLGPβAH-OH (peptide G), a pharmacological agonist of the galanin receptor GalR2, on the cardiac injury induced by administration of streptozotocin (STZ) in rats. Peptide G was prepared by solid phase peptide synthesis using the Fmoc strategy and purified by preparative HPLC; its structure was confirmed by 1H-NMR spectroscopy and MALDI-TOF mass spectrometry.

Peptide Inhibitors of the Interaction of the SARS-CoV-2 Receptor-Binding Domain with the ACE2 Cell Receptor.

Computer simulation has been used to identify peptides that mimic the natural target of the SARS-CoV-2 coronavirus spike (S) protein, the angiotensin-converting enzyme type 2 (ACE2) cell receptor. Based on the structure of the complex of the protein S receptor-binding domain (RBD) and ACE2, the design of chimeric molecules consisting of two 22-23-mer peptides linked to each other by disulfide bonds was carried out. The chimeric molecule X1 was a disulfide dimer, in which terminal cysteine residues in the precursor molecules h1 and h2 were connected by the S-S bond.

[Peptide inhibitors of the interaction of the SARS-CoV-2 receptor-binding domain with the ACE2 cell receptor].

Computer simulation has been used to identify peptides that mimic the natural target of the SARS-CoV-2 coronavirus spike (S) protein, the angiotensin converting enzyme type 2 (ACE2) cell receptor. Based on the structure of the complex of the protein S receptor-binding domain (RBD) and ACE2, the design of chimeric molecules consisting of two 22-23-mer peptides linked to each other by disulfide bonds was carried out. The chimeric molecule X1 was a disulfide dimer, in which edge cysteine residues in the precursor molecules h1 and h2 were connected by the S-S bond.

Antioxidant Properties of Galanin and Its N-Terminal Fragments in in vitro and in vivo Oxidative Stress Modeling.

Antioxidant properties of rat galanin GWTLNSAGYLLGPHAIDNHRSFSDKHGLT-NH2 (Gal), N-terminal fragment of galanin (2-15 aa) WTLNSAGYLLGPHA (G1), and its modified analogue WTLNSAGYLLGPβAH (G2) were studied in vivo in the rat model of regional myocardial ischemia and reperfusion and in vitro in the process of Cu2+-induced free radical oxidation of human blood plasma low-density lipoproteins. Intravenous administration of G1, G2, and Gal to rats after ischemia induction reduced the infarction size and activities of the necrosis markers, creatine kinase-MB and lactate dehydrogenase, in blood plasma at the end of reperfusion. G1, G2, and Gal reduced formation of the spin adducts of hydroxyl radicals in the interstitium of the area at risk during reperfusion, moreover, G2 and Gal also reduced formation of the secondary products of lipid peroxidation in the reperfused myocardium.

[Autoantibodies to M2-cholinoreceptors as a potential development factor of arrhythmia in patients with paroxysmal atrial fibrillation].

Aim: We aimed to assess autoantibodies to M2-cholinoceptors (M2-CR) in patients with paroxysmal lone atrial fibrillation (AF) and in patients with AF and arterial hypertension (AH).

Materials And Methods: 100 patients with lone AF and 84 patients with AF and AH were included. Patients underwent clinical blood and urinalysis, assessment of biochemistry blood panel, 12-lead ECG, 24-hour Holter monitoring, echocardiography and stress - testing (treadmill or stress - echocardiography).

[MeArg, NLe]-apelin-12: Optimization of solid-phase synthesis and evaluation of biological properties in vitro and in vivo.

Chemically modified peptide apelin-12 ([MeArg, NLe]-apelin12, peptide M) is able to reduce reactive oxygen species (ROS) formation, cell death, and metabolic and ionic homeostasis disorders in experimental myocardial ischemia-reperfusion injury. These beneficial effects indicate the therapeutic potential of this compound in cardiovascular diseases. The goals of this work were to optimize the synthesis of peptide M, and to study its proteolytic stability and effect on the heart function of rabbits with doxorubicin (Dox) cardiomyopathy.

Galanin receptors activation modulates myocardial metabolic and antioxidant responses to ischaemia/reperfusion stress.

The mechanisms of protective action of the neuropeptide galanin and its N-terminal fragments against myocardial ischaemia/reperfusion (I/R) injury remain obscure. The aim of this work was to study effects of a novel peptide agonist of galanin receptors [βAla14, His15]-galanin (2-15) (G1) and the full-length galanin (G2) on energy and antioxidant status of the heart with acute infarction. The peptides were synthesized by the automatic solid phase method using Fmoc technology.

[Cardiometabolic efficacy and toxicological evaluation of a pharmacological galanin receptor agonist].

The goal of this study was to examine effects of a novel galanin receptor agonist GalR1-3 [bAla14, His15]-galanine 2-15 (G), obtained by automatic solid-phase synthesis, on the metabolic state of the area at risk and the size of acute myocardial infarction (MI) in rats in vivo and evaluate its toxicity in BALB /c mice. In anesthetized rats, regional ischemia was simulated by coronary artery occlusion and then coronary blood flow was restored. The peptide G was administered intravenously (i.

[Protective action of a modified fragment of galanine in rats with doxorubicin-induced heart failure].

The use of the anticancer drug doxorubicin (Dox) is limited due to its cardiotoxic effect. Using the method of automatic solid-phase peptide synthesis, we obtained a synthetic agonist of galanin receptors GalR1-3 [RAla14, His15]-galanine (2-15) (G), exhibiting cardioprotective properties. It was purified by high performance liquid chromatography (HPLC).

Galanin/GalR1-3 system: A promising therapeutic target for myocardial ischemia/reperfusion injury.

N-terminal fragments of galanin (2-11) and (2-15) are critical for binding to GalR1-3 receptors, members of the G-protein-coupled receptor superfamily, and are involved in myocardial protection against ischemia/reperfusion (I/R) injury. This study was designed to synthesize novel GalR1-3 agonists with improved properties and evaluate their efficiency as cardioprotective agents. Peptide agonists were synthesized by the automatic solid phase method using Fmoc technology and purified by preparative HPLC.

Protective Effects of a Novel Agonist of Galanin Receptors Against Doxorubicin-Induced Cardiotoxicity in Rats.

The clinical use of antineoplastic agent doxorubicin (DOX) is limited due to its cardiotoxic action. [βAla14, His15]-galanine (2-15) (G) is a novel synthetic agonist of galanin receptors GalR1-3 having cardioprotective properties in animal models in vivo. The aim of the present study was to explore effects of G on DOX-induced cardiotoxicity.

Galanin and its N-terminal fragments reduce acute myocardial infarction in rats.

Agonists and antagonists for galanin receptor subtypes GalR1-3 can be used as putative therapeutics targets for the treatment of various human diseases. However, effects of galanin and its N-terminal fragments on myocardial ischemia/reperfusion injury remain unclear. This study was designed to assess the ability of the full-length galanin (GWTLNSAGYLLGPHAIDNHRSFSDKHGLT-NH2, G1), the natural fragments WTLNSAGYLL-NH2 (G2) and WTLNSAGYLLGPHA (G3), and their modified analogs WTLNAAGYLL (G4) and WTLNSAGYLLGPβAH (G5) to limit acute myocardial infarction in rats in vivo.

Cardioprotective properties of N-terminal galanin fragment (2-15) in experimental ischemia/reperfusion injury.

Background And Purpose: Galanin is an endogenous peptide involved in diverse physiological functions in the central nervous system including central cardiovascular regulation. The present study was designed to evaluate the potential effects of the short N-terminal galanin fragment 2-15 (G) on cardiac ischemia/reperfusion (I/R) injury.

Experimental Approach: Peptide G was synthesized by the automatic solid phase method and identified by 1H-NMR spectroscopy and mass spectrometry.

Myocardial protection from ischemia/reperfusion injury by exogenous galanin fragment.

Background And Purpose: Galanin is a multifunctional neuropeptide with pleiotropic roles. The present study was designed to evaluate the potential effects of galanin (2-11) (G1) on functional and metabolic abnormalities in response to myocardial ischemia-reperfusion (I/R) injury.

Experimental Approach: Peptide G1 was synthesized by the 9-fluorenylmethoxycarbonyl (Fmoc)-based solid-phase method.

Design of peptidase-resistant peptide inhibitors of myosin light chain kinase.

Myosin light chain kinase (MLCK) is a key regulator of various forms of cell motility including smooth muscle contraction, cell migration, cytokinesis, receptor capping, secretion, etc. Inhibition of MLCK activity in endothelial and epithelial monolayers using cell-permeant peptide Arg-Lys-Lys-Tyr-Lys-Tyr-Arg-Arg-Lys (PIK, Peptide Inhibitor of Kinase) allows protecting the barrier capacity, suggesting a potential medical use of PIK. However, low stability of L-PIK in a biological milieu prompts for development of more stable L-PIK analogues for use as experimental tools in basic and drug-oriented biomedical research.

[Cys-containing peptides cause migration of monocytes].

Automated Fmoc solid-phase technique was used to synthesize Cys-containing linear peptide fragments of monocyte chemoattractant protein-1 and chemokine domain of fractalkine along with their analogues with Cys residue being either modified or replaced with Ser. Chimeric symmetric and asymmetric disulfides were also prepared from the former linear precursors. A SAR study on a set of the newly synthesized peptides revealed that capacity to stimulate migration of monocytes and to influence cell motility in vitro, in general, critically depends on the presence of Cys free thiol group in the molecule.

[Synthetic conformational antigen, simulating the extracellular part of M2-muscarinic receptor and its reactivity with sera from patients with idiopathic arrhythmias].

Linear peptides corresponding to fragment 83-98 of the first loop and fragments 168-192 and 171-182 of the second extracellular loops of M2-muscarinic receptor (marker of early cardiac disorders and arrhythmias) were synthesized by Fmoc-SPPS method. A new conformational antigen was synthesized by method of selective ligation of linear peptides by disulfide bond with native localization. Peptides were studied in reaction with sera from patients with idiopathic arrhythmias.

[Novel conformational peptide antigen, which simulates an immunodominant epitope of the 2nd extracellular loop of β1-adrenoceptor. Computer simulation, synthesis, spatial structure].

By means of computer simulation has been built polypeptide antigen conformational structure that imitates the immunodominant epitope of the 2nd extracellular loop of β1-adrenoreceptor. A linear 25-membered peptide corresponding to calculated sequence was synthesized by means of solid-phase methoyd using Fmoc-technology, then directed by the closure ofdisulfide bridges was obtained original bicyclic polypeptide corresponding to the proposed structure of the conformational antigen. With the help of high-resolution NMR spectroscopy 3D structure of synthetic conformational antigen was investigated.

Effects of structural analogues of apelin-12 in acute myocardial infarction in rats.

Objective: To examine cardioprotective effects of Ρ-terminal fragment of adipokine apelin-12 (A12), its novel structural analogue [MeArg(1), NLe(10)]-A12 (I), and [d-Ala(12)]-A12 (II), a putative antagonist of APJ receptor, employing in vivo model of ischemia/reperfusion (I/R) injury.

Materials And Methods: Peptides were synthesized by the automatic solid phase method using Fmoc technology. Anesthetized open-chest male Wistar rats were subjected to left anterior descending (LAD) coronary artery occlusion and coronary reperfusion.

[Suppression of vascular endothelium hyperpermeability by cell-permeating peptide inhibitors of myosin light chain kinase].

Novel peptides originating from the peptide inhibitor of myosin light chain kinase, L-PIK (Arg-Lys-Lys-Tyr-Lys-Tyr-Arg-Arg-Lys), have been studied for ability to attenuate the thrombin-induced hyperpermeability of endothelial cell monolayer in culture. Peptides [NalphaMeArg1]-Lys-Lys-Tyr-Lys-Tyr-Arg-(D)Arg8-Lys and H-Arg(NO2)Lys-Lys-Tyr-Lys-Tyr-Arg-Arg-Lys-NH2 (designated PIK2 and PIK4, respectively) appeared to be the most effective inhibitors of endothelial cell monolayer hyperpermebility, and surpassed other known peptide inhibitors of myosin light chain kinase derived from original L-PIK. Our results validate PIK2 and PIK4 as the leading molecules for the development of novel drugs intended to counteract pathological hyperpermeability of vascular endothelium.

[Synthesis and cardioprotective properties of apelin-12 and its structural analogs].

The apelin-12 and a number of its analogs, resistant to degradation of proteases, were synthesized by Fmoc- method of SPPS. By-products of synthesis were examined. It was found that serine hydroxyl group was sulfating during the final deprotection of apelin-12 (I) and its analogs.