A case of deletion of the short arm of the chromosome 21 (21p-) (christchurch chromosome) discovered prenatally:clinical and cytogenetic data

Results of cytogenetic research of placental villi and amniotic fluid cells culture of the 22-weeks-old fetus with multiple congenital malformations (MCM) are presented. The absence of the short arm in one of the homologue of the chromosome 21 was revealed. Cytogenetic analysis of the fetus father's blood lymphocytes determined the similar chromosome. Further research of the father's karyotype made by FISH-method using specific DNA samples had discovered the absence of subtelomeric parts in the short arm of the chromosome 21 that might be considered as a deletion. It was suggested that the effect of position and interaction of genes could play a key role in appearing of MCM in the fetus in the case when the 21p-chromosome was transferred to it from the healthy parents.     

Molecular characterization of binding of calcium and carbohydrates by an early activation antigen of lymphocytes CD69

CD69 is the earliest leukocyte activation antigen playing a pivotal role in cellular signaling. Here, we show that a globular C-terminal domain of CD69 belonging to C-type lectins binds calcium through Asp 171, Glu 185, and Glu 187 with K(d) approximately 54 microM. Closure of the calcium-binding site results in a conformational shift of Thr 107 and Lys 172. Interestingly, structural changes in all of these amino acids lead to the formation of high-affinity binding sites for N-acetyl-D-glucosamine. Similarly, a structural change in Glu 185 and Glu 187 contributes to a high-affinity site for N-acetyl-D-galactosamine. Site-directed mutagenesis and molecular modeling allowed us to describe the structural details of binding sites for both carbohydrates. These studies explain the importance of calcium for recognition of carbohydrates by CD69 and provide an important paradigm for the role of weak interactions in the immune system.     

Linear Dichroism,Fluorescence Polarization,and Path of the Thermal Deactivation of Excited Cyanobacterial (Synechococcus Elongatus) Photosystem 1 Immobilized and Oriented in Polymer Films

Pigment-protein complexes enriched in photosystem 1 (PS1) and, for comparison, enriched in photosystem 2 (PS2) were isolated from the cyanobacterium Synechococcus elongatus Nag. f. thermalis Geitl. They were immobilized and oriented in the polyvinyl alcohol (PVA) films, and studied by linear dichroism (LD), fluorescence polarization (FP), photoacoustic spectroscopy (PAS), and polarized photoacoustic spectroscopy (PAS and PAS). The LD signal of -carotene in the region with maximum at 500 nm was positive in the PS1 complex. The maximum value of fluorescence polarization (FP) in the measured photosynthetic pigment region was 1.25 and was similar to higher plant values. Carotenoids exhibited different efficiencies of thermal deactivation (max. at 500 nm) in PS1 and PS2. The thermal deactivation efficiency of carotenoids in comparison with that of chlorophyll (Chl) a at its red absorbance maximum was much higher in PS1 than in PS2 complexes. Cyanobacterial complexes did not contain Chl b, interpretation of the LD, PAS, and FP results is thus easier and can be compared with PS1 and PS2 values of higher plants, especially with Chl b-less mutant values.     

A Systems-Level Interrogation Identifies Regulators of Drosophila Blood Cell Number and Survival

In multicellular organisms, cell number is typically determined by a balance of intracellular signals that positively and negatively regulate cell survival and proliferation. Dissecting these signaling networks facilitates the understanding of normal development and tumorigenesis. Here, we study signaling by the Drosophila PDGF/VEGF Receptor (Pvr) in embryonic blood cells (hemocytes) and in the related cell line Kc as a model for the requirement of PDGF/VEGF receptors in vertebrate cell survival and proliferation. The system allows the investigation of downstream and parallel signaling networks, based on the ability of Pvr to activate Ras/Erk, Akt/TOR, and yet-uncharacterized signaling pathway/s, which redundantly mediate cell survival and contribute to proliferation. Using Kc cells, we performed a genome wide RNAi screen for regulators of cell number in a sensitized, Pvr deficient background. We identified the receptor tyrosine kinase (RTK) Insulin-like receptor (InR) as a major Pvr Enhancer, and the nuclear hormone receptors Ecdysone receptor (EcR) and ultraspiracle (usp), corresponding to mammalian Retinoid X Receptor (RXR), as Pvr Suppressors. In vivo analysis in the Drosophila embryo revealed a previously unrecognized role for EcR to promote apoptotic death of embryonic blood cells, which is balanced with pro-survival signaling by Pvr and InR. Phosphoproteomic analysis demonstrates distinct modes of cell number regulation by EcR and RTK signaling. We define common phosphorylation targets of Pvr and InR that include regulators of cell survival, and unique targets responsible for specialized receptor functions. Interestingly, our analysis reveals that the selection of phosphorylation targets by signaling receptors shows qualitative changes depending on the signaling status of the cell, which may have wide-reaching implications for other cell regulatory systems.     

Significance of thymosin β4 and implication of PINCH-1-ILK-α-parvin (PIP) complex in human dilated cardiomyopathy

Myocardial remodeling is a major contributor in the development of heart failure (HF) after myocardial infarction (MI). Integrin-linked kinase (ILK), LIM-only adaptor PINCH-1, and α-parvin are essential components of focal adhesions (FAs), which are highly expressed in the heart. ILK binds tightly to PINCH-1 and α-parvin, which regulates FA assembly and promotes cell survival via the activation of the kinase Akt. Mice lacking ILK, PINCH or α-parvin have been shown to develop severe defects in the heart, suggesting that these proteins play a critical role in heart function. Utilizing failing human heart tissues (dilated cardiomyopathy, DCM), we found a 2.27-fold (p<0.001) enhanced expression of PINCH, 4 fold for α-parvin, and 10.5 fold (p<0.001) for ILK as compared to non-failing (NF) counterparts. No significant enhancements were found for the PINCH isoform PINCH-2 and parvin isoform β-parvin. Using a co-immunoprecipitation method, we also found that the PINCH-1-ILK-α-parvin (PIP) complex and Akt activation were significantly up-regulated. These observations were further corroborated with the mouse myocardial infarction (MI) and transaortic constriction (TAC) model. Thymosin beta4 (Tβ4), an effective cell penetrating peptide for treating MI, was found to further enhance the level of PIP components and Akt activation, while substantially suppressing NF-κB activation and collagen expression--the hallmarks of cardiac fibrosis. In the presence of an Akt inhibitor, wortmannin, we show that Tβ4 had a decreased effect in protecting the heart from MI. These data suggest that the PIP complex and activation of Akt play critical roles in HF development. Tβ4 treatment likely improves cardiac function by enhancing PIP mediated Akt activation and suppressing NF-κB activation and collagen-mediated fibrosis. These data provide significant insight into the role of the PIP-Akt pathway and its regulation by Tβ4 treatment in post-MI.     

Discovery of a potent and selective aurora kinase inhibitor

This communication describes the discovery of a novel series of Aurora kinase inhibitors. Key SAR and critical binding elements are discussed. Some of the more advanced analogues potently inhibit cellular proliferation and induce phenotypes consistent with Aurora kinase inhibition. In particular, compound 21 (SNS-314) is a potent and selective Aurora kinase inhibitor that exhibits significant activity in pre-clinical in vivo tumor models.     

Tethering identifies fragment that yields potent inhibitors of human caspase-1

Disulfide Tethering was applied to the active site of human caspase-1, resulting in the discovery of a novel, tricyclic molecular fragment that selectively binds in S4. This fragment was developed into a class of potent inhibitors of human caspase-1. Several key analogues determined the optimal distance of the tricycle from the catalytic residues, the relative importance of various features of the tricycle, and the importance of the linker.     

Molecular-cytogenetic study of the aborted fetuses in women with reproductive function disorders

It is known that the frequency of chromosomal abnormalities among spontaneous miscarriages of the first trimester of pregnancy makes 50-60%. Research of karyotypes of chorionic villus cells of miscarriages has been conducted by combining the standard cytogenetic method and the FISH analysis on interphase nuclei of centromeric specific DNA samples by the tests to the chromosomes 13/21, 14/22, 15, 16, 18, X, Y. The described complex approach can be successfully applied for effective identification ofchromosomal abnormalities in the material of spontaneous miscarriages. The results specify the necessity of careful study of genomes of matrimonial pairs with the usual unmaturing in anamnesis and especially before treatment by IVF methods.     

Bone marrow support of the heart in pressure overload is lost with aging

Rationale

Exogenous stem cell delivery is under investigation to prevent and treat cardiac dysfunction. It is less studied as to the extent endogenous bone marrow derived stem cells contribute to cardiac homeostais in response to stress and the affects of aging on this stress response.

Objective

To determine the role of bone marrow (BM) derived stem cells on cardiac homeostasis in response to pressure overload (PO) and how this response is altered by aging.

Methods and Results

Young (8 weeks) and old (>40 weeks) C57/b6 mice underwent homo- and heterochronic BM transplantation prior to transverse aortic constriction (TAC). We found that older BM is associated with decreased cardiac function following TAC. This decreased function is associated with decrease in BM cell engraftment, increased myocyte apoptosis, decreased myocyte hypertrophy, increased myocardial fibrosis and decreased cardiac function. Additionally, there is a decrease in activation of resident cells within the heart in response to PO in old mice. Interestingly, these effects are not due to alterations in vascular density or inflammation in response to PO or differences in ex vivo stem cell migration between young and old mice.

Conclusions

BM derived stem cells are activated in response to cardiac PO, and the recruitment of BM derived cells are involved in cardiac myocyte hypertrophy and maintenance of function in response to PO which is lost with aging.