Exosomes for angiogenesis induction in ischemic disorders

Ischaemic disorders are leading causes of morbidity and mortality worldwide. While the current therapeutic approaches have improved life expectancy and quality of life, they are unable to “cure” ischemic diseases and instate regeneration of damaged tissues. Exosomes are a class of extracellular vesicles with an average size of 100–150 nm, secreted by many cell types and considered a potent factor of cells for paracrine effects. Since exosomes contain multiple bioactive components such as growth factors, molecular intermediates of different intracellular pathways, microRNAs and nucleic acids, they are considered as cell-free therapeutics. Besides, exosomes do not rise cell therapy concerns such as teratoma formation, alloreactivity and thrombotic events. In addition, exosomes are stored and utilized more convenient. Interestingly, exosomes could be an ideal complementary therapeutic tool for ischemic disorders. In this review, we discussed therapeutic functions of exosomes in ischemic disorders including angiogenesis induction through various mechanisms with specific attention to vascular endothelial growth factor pathway. Furthermore, different delivery routes of exosomes and different modification strategies including cell preconditioning, gene modification and bioconjugation, were highlighted. Finally, pre-clinical and clinical investigations in which exosomes were used were discussed.     

An Extended,Boolean Model of the Septation Initiation Network in S.Pombe Provides Insights into Its Regulation

Cytokinesis in fission yeast is controlled by the Septation Initiation Network (SIN), a protein kinase signaling network using the spindle pole body as scaffold. In order to describe the qualitative behavior of the system and predict unknown mutant behaviors we decided to adopt a Boolean modeling approach. In this paper, we report the construction of an extended, Boolean model of the SIN, comprising most SIN components and regulators as individual, experimentally testable nodes. The model uses CDK activity levels as control nodes for the simulation of SIN related events in different stages of the cell cycle. The model was optimized using single knock-out experiments of known phenotypic effect as a training set, and was able to correctly predict a double knock-out test set. Moreover, the model has made in silico predictions that have been validated in vivo, providing new insights into the regulation and hierarchical organization of the SIN.     

Guaianolide from Jurinea carduiformis

8-Desacylrepin, a new guaianolide, has been isolated from Jurinea carduiformis.     

DNA sequence representation without degeneracy

Graphical representation of DNA sequence provides a simple way of viewing, sorting and comparing various gene structures. A new two-dimensional graphical representation method using a two- quadrant Cartesian coordinates system has been derived for mathematical denotation of DNA sequence. The two-dimensional graphic representation resolves sequences’ degeneracy and is mathematically proven to eliminate circuit formation. Given x-projection and y-projection of any point on the graphical representation, the number of A, G, C and T from the beginning of the sequence to that point could be found. Compared with previous methods, this graphical representation is more in-line with the conventional recognition of linear sequences by molecular biologists, and also provides a metaphor in two dimensions for local and global DNA sequence comparison.     

In vitro and in silico processes to identify differentially expressed proteins

We present an integrated proteomics platform designed for performing differential analyses. Since reproducible results are essential for comparative studies, we explain how we improved reproducibility at every step of our laboratory processes, e.g. by taking advantage of the powerful laboratory information management system we developed. The differential capacity of our platform is validated by detecting known markers in a real sample and by a spiking experiment. We introduce an innovative two-dimensional (2-D) plot for displaying identification results combined with chromatographic data. This 2-D plot is very convenient for detecting differential proteins. We also adapt standard multivariate statistical techniques to show that peptide identification scores can be used for reliable and sensitive differential studies. The interest of the protein separation approach we generally apply is justified by numerous statistics, complemented by a comparison with a simple shotgun analysis performed on a small volume sample. By introducing an automatic integration step after mass spectrometry data identification, we are able to search numerous databases systematically, including the human genome and expressed sequence tags. Finally, we explain how rigorous data processing can be combined with the work of human experts to set high quality standards, and hence obtain reliable (false positive < 0.35%) and nonredundant protein identifications.     

Methyl jasmonate ameliorates lead toxicity in Oryza sativa by modulating chlorophyll metabolism,antioxidative capacity and metal translocation

Lead (Pb) not only negatively alters plant growth and yield but may also have potentially toxic risks to human health. Nevertheless, the interaction between rice (Oryza sativa L.) plants and the molecular cell dynamics induced by lead-methyl jasmonate (MJ) remains unknown. Here, plants were hydroponically exposed to Pb (150 and 300 µM) alone or in combination with 0.5 and 1 µM MJ. The application of MJ modulated the expression of the HMAs, PCS1, PCS2 and ABCC1 genes, thereby immobilizing the Pb in the roots and lessening its translocation to the aerial parts of the rice plant. The supplementation of MJ improved the growth and yield of Pb-stressed rice by adjusting the proline and chlorophyll metabolism, increasing the phytochelatins (PCs) accumulation and diminishing the accumulation of Pb in the shoots. the application of MJ alleviated the oxidative stress of rice plants exposed to Pb toxicity by enhancing the activity of antioxidant enzymes and enzymes of the glyoxalase system (glyoxalase I and II) and decreasing the endogenous levels of malondialdehyde (MDA), hydrogen peroxide (H₂O₂) and methylglyoxal (MG). Therefore, the results of the present study could provide a molecular insight and cellular interplay scheme for the development of a promising strategy in Pb-contaminated areas to produce healthy food.     

Serum-free cryopreservation of human amniotic epithelial cells before and after isolation from their natural scaffold

Amniotic epithelial cells are a promising source for stem cell-based therapy through their potential capacity to differentiate into the cell lineages of all three germ layers. Long-term preservation is necessary to have a ready-to-use source of stem cells, when required. Reduced differentiation capability, decrease of viability and use of fetal bovine serum (FBS) are three drawbacks of clinical application of cryopreserved stem cells. In this study, we used human amniotic fluid instead of animal serum, and evaluated viability and multipotency of amniotic epithelial cells after cryopreservation in suspension and compared with those cryopreserved on their natural scaffold (in situ cryopreservation). There was no significant difference in viability of the cells cryopreserved in amniotic fluid and FBS. Also, the same results were achieved for expression of pluripotency marker OCT-4 when FBS was replaced by amniotic fluid in the samples with the same cryoprotectant. The cells cryopreserved in presence of scaffold had a higher level of viability compared to the cells cryopreserved in suspension. Although, the number of the cells expressed OCT-4 significantly decreased within cryopreservation in suspension, no decrease in expression of OCT-4 was observed when the cells cryopreserved with their natural scaffold. Upon culturing of post-thawed cells in specific lineage differentiating mediums, the markers of neuronal, hepatic, cardiomyocytic and pancreatic were found in differentiated cells. These results show that replacement of FBS by amniotic fluid and in situ cryopreservation of amniotic epithelial cells is an effective approach to overcome limitations related to long-term preservation including differentiation during cryopreservation and decrease of viability.