Matrix Rigidity-Modulated Cardiovascular Organoid Formation from Embryoid Bodies

Stem cell clusters, such as embryoid bodies (EBs) derived from embryonic stem cells, are extensively studied for creation of multicellular clusters and complex functional tissues. It is common to control phenotypes of ES cells with varying molecular compounds; however, there is still a need to improve the controllability of cell differentiation, and thus, the quality of created tissue. This study demonstrates a simple but effective strategy to promote formation of vascularized cardiac muscle - like tissue in EBs and form contracting cardiovascular organoids by modulating the stiffness of a cell adherent hydrogel. Using collagen-conjugated polyacrylamide hydrogels with controlled elastic moduli, we discovered that cellular organization in a form of vascularized cardiac muscle sheet was maximal on the gel with the stiffness similar to cardiac muscle. We envisage that the results of this study will greatly contribute to better understanding of emergent behavior of stem cells in developmental and regeneration process and will also expedite translation of EB studies to drug-screening device assembly and clinical treatments.     

Voltammetric studies of glutathione transfer across arrays of liquid–liquid microinterfaces for sensing applications

Amino Acids - The simple and facilitated transfer of tripeptide glutathione across the water/2-nitrophenyl octhyl ether interface was studied via cyclic voltammetry at interface between two...     

Structure-based design, synthesis, and SAR evaluation of a new series of 8-hydroxyquinolines as HIF-1alpha prolyl hydroxylase inhibitors

A new series of potent 8-hydroxyquinolines was designed based on the newly resolved X-ray crystal structure of EGLN-1. Both alkyl and aryl 8-hydroxyquinoline-7-carboxyamides were good HIF-1alpha prolyl hydroxylase (EGLN) inhibitors. In subsequent VEGF induction assays, these exhibited potent VEGF activity. In addition, this class of compounds did show the ability to stabilize HIF-1alpha.     

Molecular architecture of leishmania EF-1alpha reveals a novel site that may modulate protein translation: a possible target for drug development

Elongation factor-1alpha plays an essential role in eukaryotic protein biosynthesis. Recently, we have shown by protein structure modeling the presence of a hairpin-loop of 12 amino acids in mammalian EF-1alpha that is absent in the leishmania homologue [D. Nandan, A. Cherkasov, R. Sabouti, T. Yi, N.E. Reiner, Molecular cloning, biochemical and structural analysis of elongation factor-1 alpha from Leishmania donovani: comparison with the mammalian homologue, Biochem. Biophys. Res. Commun. 302 (2003) 646-652]. As a consequence of this deletion, an exposed region is available on the main body of leishmania EF-1alpha. Here we report the generation of an anti-EF-1alpha antibody (DN-3) which bound selectively to the exposed region of leishmania EF-1alpha, with no reactivity with human EF-1alpha. In a leishmania cell-free protein translation system, DN-3 substantially inhibited protein translation. A similar inhibitory effect was observed when a specific peptide based on the exposed region was used in the cell-free protein translation assay. The application of structure-based in silico methods to identify potential ligands to target the exposed region identified a small molecule that selectively attenuated in vitro translation using leishmania extracts. Moreover, this small molecule showed selective suppressive effect on multiplication of leishmania in culture. Taken together, these findings identify a novel, exposed region in leishmania EF-1alpha that may be involved in protein synthesis and a potential site for drug targeting.     

Dual effect of heat shock on DNA replication and genome integrity

Heat shock (HS) is one of the better-studied exogenous stress factors. However, little is known about its effects on DNA integrity and the DNA replication process. In this study, we show that in G1 and G2 cells, HS induces a countable number of double-stranded breaks (DSBs) in the DNA that are marked by γH2AX. In contrast, in S-phase cells, HS does not induce DSBs but instead causes an arrest or deceleration of the progression of the replication forks in a temperature-dependent manner. This response also provoked phosphorylation of H2AX, which appeared at the sites of replication. Moreover, the phosphorylation of H2AX at or close to the replication fork rescued the fork from total collapse. Collectively our data suggest that in an asynchronous cell culture, HS might affect DNA integrity both directly and via arrest of replication fork progression and that the phosphorylation of H2AX has a protective effect on the arrested replication forks in addition to its known DNA damage signaling function.     

Model acupuncture point:Bone marrow-derived stromal stem cells are moved by a weak electromagnetic field

AIM To show the existence of a structural formative role of magnetic fields(MFs) with respect to biological objects by using our proposed model of an acupoint.METHODS We introduced a magnetised 10-100 μT metal rod(needle) into culture dishes with a negatively charged working surface and observed during 24 h how cells were arranged by MFs and by electrical fields(EFs) when attached. Rat and human bone marrow-derived stromal stem cells(r BMSCs and h BMSCs), human nonadherent mononuclear blood cells, NCTCs and A172 cells, and Escherichia coli(E. coli) were evaluated. The dish containing BMSCs was defined as the model of an acupoint. r BMSCs proliferative activity affected by the needle was investigated. For investigating electromagnetic field structures, we used the gas discharge visualisation(GDV) method.RESULTS During 24 h of incubation in 50-mm culture dishes, BMSCs or the nonadherent cells accumulated into a central heap in each dish. BMSCs formed a torus(central ring) with an inner diameter of approximately10 mm only upon the introduction of the needle in the centre of the dish. The cells did not show these effects in 35- or 90-mm culture dishes or hydrophobic dishes or rectangular cuvettes. NCTCs and A172 cells showed unstable the effects and only up to two weeks after thawing. Moreover, we observed that the appearance of these effects depended on the season. In winter, BMSCs showed no the effects. GDV experiments revealed that the resonant annular illumination gradually formed from 10 to 18-20 s in polar solutions with and without cell suspension of BMSCs, NCTCs and E. coli when using circular 50-mm dishes, stimulation at 115 V and switching of the electrode poles at 1 kH z. All these data demonstrate the resonant nature of the central ring. Significant influence of MFs on the rB MSC proliferation rate was not observed.CONCLUSION BMSCs can be moved by MFs when in the presence of a constant EF and MF, when the cells are in the responsive functional state, and when there is a resonant relationship between them.     

Association of insulinase gene polymorphisms with type 2 diabetes mellitus in patients from the Moscow population

Association of 13 single nucleotide polymorphisms (SNPs) of insulinase (IDE) gene with type 2 diabetes mellitus (T2D) in the Moscow population has been examined. Three polymorphic markers (rs7078413, rs7899603, and rs551266) associated with the risk of T2D development have been revealed. Allele and genotype frequency distribution for these three markers differed significantly only in the sample of females between T2D patients and control individuals, while only in case of rs7078413 SNP genotype frequencies varied significantly in the total population.