TGFß1 Regulates Cellular Composition of In Vitro Cardiac Perivascular Niche Based on Cardiospheres.

The cardiac perivascular niche is a cellular microenvironment of a blood vessel. The principles of niche regulation are still poorly understood. We studied the effect of TGFß1 on cells forming the cardiac perivascular niche using 3D cell culture (cardiospheres). Cardiospheres contained progenitor (c-Kit), endothelial (CD31), and mural (αSMA) cells, basement membrane proteins (laminin) and extracellular matrix proteins (collagen I, fibronectin). TGFß1 treatment decreased the length of CD31+ microvasculature, VE cadherin protein level, and proportion of NG2+ cells, and increased proportion of αSMA+ cells and transgelin/SM22α protein level. We supposed that this effect is related to the stabilizing function of TGFß1 on vascular cells: decreased endothelial cell proliferation, as shown for HUVEC, and activation of mural cell differentiation.

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. In the chimeric molecule X2, the disulfide bond was located in the middle of each precursor peptide molecule. The precursors h1 and h2 mimic amino acid sequences of α1- and α2-helices of the ACE2 extracellular peptidase domain, respectively, keeping intact most of the amino acid residues involved in the interaction with RBD. The aim of the work was to evaluate the binding efficiency of chimeric molecules and their constituent peptides with RBD (particularly in dependence of the middle and terminal methods of fixing the initial peptides h1 and h2). The proposed polypeptides and chimeric molecules were synthesized by chemical methods, purified to 95-97% purity, and characterized by HPLC and MALDI-TOF mass spectrometry. Binding of these peptides to the SARS-CoV-2 RBD was evaluated by microthermophoresis with recombinant domains corresponding in sequence to the original Chinese (GenBank ID NC_045512.2) and the British (B. 1.1.7, GISAID EPI_ISL_683466) variants. The original RBD of the Chinese variant bound to three synthesized peptides: linear h2 and both chimeric variants. Chimeric peptides were also bound to the RBD of the British variant. The antiviral activity of the proposed peptides was evaluated in Vero cell line.

The Role of Urokinase, Tumor Necrosis Factor, and Matrix Metalloproteinase-9 in Monocyte Activation.

TNFα mediates the expression of MMP-9 in THP-1 monocytes induced by urokinase (uPA). Upregulation of MMP-9 caused by uPA and TNFα is suppressed by etanercept, a TNFα inhibitor. In addition, uPA stimulates TNFα mRNA expression. Both uPA and TNFα induce ROS generation in monocytes, while MMP-9 secretion induced by uPA and TNFα is inhibited by antioxidants. Inhibitors of NFκB, ligands of PPARα and PPARγ receptors, and SIRT1 activators negatively affect MMP-9 secretion induced by uPA. MMP-9 secretion during monocyte differentiation into macrophages is downregulated by etanercept and antioxidants. These factors as well as MMP inhibitor GM6001 reduce the number of macrophages attached to substrate during cell differentiation, indicating the role of urokinase, TNFα, and ROS in MMP expression in monocytes and MMP involvement in macrophage maturation.

[Epicardial Transplantation of Cardiac Progenitor Cells Based Cells Sheets is More Promising Method for Stimulation of Myocardial Regeneration, Than Conventional Cell Injections].

Today, transplantation of stem / progenitor cells is a promising approach for the treatment of heart diseases. The therapeutic potential of transplanted cells directly depends on the method of delivery to the myocardium, which determines their regenerative properties. It is important for the development of effective methods of cell therapy. In this paper, we performed a comparative study of efficacy of cardiac progenitor cell (CPC) transplantation by intramyocardial needle injections and by tissue engineering constructs (TEC) - "cell sheets" consisting of cells and their extracellular matrix. It has been shown, that transplantation of TEC in comparison with the intramyocardial delivery provides more extensive distribution and retains more proliferating cellular elements in the damaged myocardium, attenuates the negative cardiac remodeling of the left ventricle and promotes its vascularization.

Nonviral transfection of adipose tissue stromal cells: an experimental study.

Delivery of plasmid DNA and interfering RNA into adipose tissue stromal cells was carried out by the methods of lipofection, calcium phosphate method, and by electroporation. The percent of transfected cells after delivery of plasmid DNA by the calcium phosphate method and lipofection was 0 and 15%, respectively, vs. more than 50% after electroporation. Similar results were obtained for delivery of short-strand RNA into cells. These data indicate that electroporation is the most effective method of nonviral transfection of adipose tissue stromal cells.

Alteration of beta-adrenoceptor function in hypertensive patients with different degrees of left ventricular hypertrophy.

Previous assessment of beta-adrenoceptor function has shown alterations in essential hypertension (EH). In the present study, we compared lymphocyte beta-adrenoceptor density (Bmax) and adenylate cyclase (AC) activity stimulated by l-isoproterenol, Gpp(NH)p, Gpp(NH)p + l-isoproterenol, and forskolin in 46 patients with EH and in 17 normotensive subjects. The patients with EH were divided into two subgroups, one with left ventricular myocardial mass (LVMM) less than 200 g and the second with LVMM greater than 200 g (according to Teichholz' formula). There were no significant differences in Bmax or in AC activity [basal and stimulated by Gpp(NH)p and forskolin] between the patients and the normotensive subjects. Adenylate cyclase activity stimulated by l-isoproterenol was reduced (% from basal AC) in the patients (P less than .05), and Bmax was increased only in the patients with left ventricular hypertrophy (P less than .05). There were no differences in AC activity between the two patient subgroups, and Bmax and AC activity did not correlate with blood pressure in either the patients or the normotensive subjects. Correlations were found between Bmax and LVMM (r = 0.38, P less than .02) and between Bmax and interventricular septum thickness (r = 0.412, P less than .02) among the patients. Thus, beta-adrenergic-mediated AC sensitivity to catecholamines is reduced in patients with EH and may represent a generalized defect in beta-receptor function in EH. Increased Bmax is likely to characterize more pronounced involvement of the target organs in the pathologic process associated with EH than is a higher blood pressure level.

Characteristics of lymphocyte beta-adrenoceptors in essential hypertension: effects of propranolol treatment and dynamic exercise.

The density of beta 2-receptors in intact lymphocytes was studied by binding with 125iodo-cyanopindolol in 18 male patients with mild or moderate hypertension before and after monotherapy with propranolol. The density of these receptors was also determined in 5 patients before and after dynamic exercise. We found that propranolol therapy evoked different changes in the density of beta-receptors in patients with essential hypertension. Based on these results, all patients were divided into two groups: (a) patients who responded to the administration of propranolol by an increase in receptor density and (b) patients who responded with a decrease in receptor density. Propranolol therapy had a pronounced hypotensive effect in the second group and no hypotensive effect in the first group. In the second group, heart rate was significantly higher initially and showed a significantly greater decrease after treatment. The initial values for beta 2-receptor density were also significantly higher in this group than in the first group. Mean values of baseline plasma renin activity (PRA) were higher in the second group, but this difference was nonsignificant. The 5 patients who participated in dynamic exercise exhibited different changes in beta-receptor density, which correlated with the changes observed with propranolol treatment. There was no correlation between PRA and the density of beta 2-receptors in lymphocytes. Positive correlations were found between the density of these receptors and left-ventricular myocardial mass and interventricular septal thickness. The data indicate that the density of these receptors in lymphocytes is regulated in a qualitatively different manner in the two groups of patients with essential hypertension; this difference appears to be related to baseline renin levels or, perhaps, catecholamine levels. Additional studies are needed to clarify the regulation of beta 2-receptors in essential hypertension.