N1,N3-disubstituted uracils as nonnucleoside inhibitors of HIV-1 reverse transcriptase

A series of phenyloxyethyl and cinnamyl derivatives of substituted uracils were synthesized and found to exhibit potent activity against HIV-RT and HIV replication in cell culture. In general, the cinnamyl derivatives proved superior to the phenyloxyethyl derivatives, however 1-[2-(4-methylphenoxy)ethyl]-3-(3,5-dimethylbenzyl)uracil (19) exhibited the highest activity (EC₅₀ = 0.27 μM) thus confirming that the 3-benzyluracil fragment in the NNRTI structure can be regarded as a functional analogue of the benzophenone pharmacophore typically found in NNRTIs.     

Phototoxic effects of fluorescent protein KillerRed on tumor cells in mice

KillerRed is known to be a unique red fluorescent protein displaying strong phototoxic properties. Its effectiveness has been shown previously for killing bacterial and cancer cells in vitro. Here, we investigated the photototoxicity of the protein on tumor xenografts in mice. HeLa Kyoto cell line stably expressing KillerRed in mitochondria and in fusion with histone H2B was used. Irradiation of the tumors with 593 nm laser led to photobleaching of KillerRed indicating photosensitization reaction and caused significant destruction of the cells and activation of apoptosis. The portion of the dystrophically changed cells increased from 9.9% to 63.7%, and the cells with apoptosis hallmarks from 6.3% to 14%. The results of this study suggest KillerRed as a potential genetically encoded photosensitizer for photodynamic therapy of cancer. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

An HIV-1 Envelope Glycoprotein Trimer with an Embedded IL-21 Domain Activates Human B Cells

Broadly neutralizing antibodies (bNAbs) that target the HIV-1 envelope glycoproteins (Env) can prevent virus acquisition, but several Env properties limit its ability to induce an antibody response that is of sufficient quantity and quality. The immunogenicity of Env can be increased by fusion to co-stimulatory molecules and here we describe novel soluble Env trimers with embedded interleukin-4 (IL-4) or interleukin-21 (IL-21) domains, designed to activate B cells that recognize Env. In particular, the chimeric Env_IL-21 molecule activated B cells efficiently and induced the differentiation of antibody secreting plasmablast-like cells. We studied whether we could increase the activity of the embedded IL-21 by designing a chimeric IL-21/IL-4 (ChimIL-21/4) molecule and by introducing amino acid substitutions in the receptor binding domain of IL-21 that were predicted to enhance its binding. In addition, we incorporated IL-21 into a cleavable Env trimer and found that insertion of IL-21 did not impair Env cleavage, while Env cleavage did not impair IL-21 activity. These studies should guide the further design of chimeric proteins and Env_IL-21 may prove useful in improving antibody responses against HIV-1.     

Glycine and Folate Ameliorate Models of Congenital Sideroblastic Anemia

Sideroblastic anemias are acquired or inherited anemias that result in a decreased ability to synthesize hemoglobin in red blood cells and result in the presence of iron deposits in the mitochondria of red blood cell precursors. A common subtype of congenital sideroblastic anemia is due to autosomal recessive mutations in the SLC25A38 gene. The current treatment for SLC25A38 congenital sideroblastic anemia is chronic blood transfusion coupled with iron chelation. The function of SLC25A38 is not known. Here we report that the SLC25A38 protein, and its yeast homolog Hem25, are mitochondrial glycine transporters required for the initiation of heme synthesis. To do so, we took advantage of the fact that mitochondrial glycine has several roles beyond the synthesis of heme, including the synthesis of folate derivatives through the glycine cleavage system. The data were consistent with Hem25 not being the sole mitochondrial glycine importer, and we identify a second SLC25 family member Ymc1, as a potential secondary mitochondrial glycine importer. Based on these findings, we observed that high levels of exogenous glycine, or 5-aminolevulinic acid (5-Ala) a metabolite downstream of Hem25 in heme biosynthetic pathway, were able to restore heme levels to normal in yeast cells lacking Hem25 function. While neither glycine nor 5-Ala could ameliorate SLC25A38 congenital sideroblastic anemia in a zebrafish model, we determined that the addition of folate with glycine was able to restore hemoglobin levels. This difference is likely due to the fact that yeast can synthesize folate, whereas in zebrafish folate is an essential vitamin that must be obtained exogenously. Given the tolerability of glycine and folate in humans, this study points to a potential novel treatment for SLC25A38 congenital sideroblastic anemia.     

Ligation of Glycophorin A Generates Reactive Oxygen Species Leading to Decreased Red Blood Cell Function

Acute, inflammatory conditions associated with dysregulated complement activation are characterized by significant increases in blood concentration of reactive oxygen species (ROS) and ATP. The mechanisms by which these molecules arise are not fully understood. In this study, using luminometric- and fluorescence-based methods, we show that ligation of glycophorin A (GPA) on human red blood cells (RBCs) results in a 2.1-fold, NADPH-oxidase-dependent increase in intracellular ROS that, in turn, trigger multiple downstream cascades leading to caspase-3 activation, ATP release, and increased band 3 phosphorylation. Functionally, using 2D microchannels to assess membrane deformability, GPS-ligated RBCs travel 33% slower than control RBCs, and lipid mobility was hindered by 10% using fluorescence recovery after photobleaching (FRAP). These outcomes were preventable by pretreating RBCs with cell-permeable ROS scavenger glutathione monoethyl ester (GSH-ME). Our results obtained in vitro using anti-GPA antibodies were validated using complement-altered RBCs isolated from control and septic patients. Our results suggest that during inflammatory conditions, circulating RBCs significantly contribute to capillary flow dysfunctions, and constitute an important but overlooked source of intravascular ROS and ATP, both critical mediators responsible for endothelial cell activation, microcirculation impairment, platelet activation, as well as long-term dysregulated adaptive and innate immune responses.     

Effects of low-level combined static and weak low-frequency alternating magnetic fields on cytokine production and tumor development in mice

We investigated the effects of weak combined magnetic fields (MFs) produced by superimposing a constant MF (in the range 30 - 150 µT) and an alternating MF (100 or 200 nT) on cytokine production in healthy Balb/C male mice exposed 2 h daily for 14 days. The alternating magnetic field was a sum of several frequencies (ranging from 2.5 - 17.5 Hz). The frequencies of the alternating magnetic field were calculated formally based on the cyclotron resonance of ions of free amino acids (glutamic and aspartic acids, arginine, lysine, histidine, and tyrosine). The selection of different intensity and frequency combinations of constant and alternating magnetic fields was performed to find the optimal characteristics for cytokine production stimulation in immune cells. MF with a constant component of 60 μT and an alternating component of 100 nT, which was a sum of six frequencies (from 5 to 7 Hz), was found to stimulate the production of tumor necrosis factor-α, interferon-gamma, interleukin-2, and interleukin-3 in healthy mouse cells and induce cytokine accumulation in blood plasma. Then, we studied the effect of this MF on tumor-bearing mice with solid tumors induced by Ehrlich ascite carcinoma cells by observing tumor development processes, including tumor size, mouse survival rate, and average lifespan. Tumor-bearing mice exposed to a combined constant magnetic field of 60 μT and an alternating magnetic field of 100 nT containing six frequencies showed a strong suppression of tumor growth with an increase in survival rate and enhancement of average lifespan.     

Deterministic Somatic Cell Reprogramming Involves Continuous Transcriptional Changes Governed by Myc and Epigenetic-Driven Modules

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The peptide analogue of MCP-1 65-76 sequence is an inhibitor of inflammation

Inflammation plays an important role in vessel wall remodeling that occurs in atherosclerosis and postangioplasty restenosis. Monocytic chemoattractant protein-1 (MCP-1) is one of the main attractors of monocytes and some lymphocyte subsets to the damaged vessel. The aims of the study were to confirm MCP-1 participation in the development of acute coronary syndromes, to produce the potential MCP-1 peptide antagonist, and to investigate its effects in vitro and in vivo in different animal models of inflammation. MCP-1 plasma concentration was measured by ELISA (enzyme-linked immunosorbent assay). Chemokine receptor expression by cells isolated from human atherosclerotic lesions was assessed by direct immunofluorescence and flow cytometry. MCP-1 sequence was analyzed with Peptide Companion software and peptides were synthesized using Fmoc strategy. The peptide resistance to degradation was checked by 1H-NMR spectroscopy. The peptide effect on MCP-1-stimulated cell migration was studied in Boyden chamber and in mouse air pouch model, and its influence on lipopolysaccharide (LPS)-induced inflammatory cell recruitment was investigated in models of subcutaneous inflammation in rats and nonhuman primates. We revealed nearly a 2-fold increase of MCP-1 plasma level in patients with unstable angina in comparison with patients with stable angina. The atherosclerotic plaque specimens obtained from patients with unstable angina contained a significant amount of chemokine receptor-expressing leukocytes. Peptide from MCP-1 C-terminal 65-76 sequence (peptide X) inhibited MCP-1-stimulated monocytic cell migration in vitro and in vivo. Peptide X labeled with 99mTc accumulated specifically at sites of inflammation in rats. Peptide X administrated i.m and i.v. suppressed monocyte and granulocyte recruitment induced by subcutaneous injection of LPS in the back of rats and non-human primates. Our data demonstrate that MCP-1-mediated chemotaxis could be responsible for atherosclerotic plaque "destabilization". Peptide X may represent a new class of anti-inflammatory drugs to be used in cardiology.     

Synthesis of triazole-linked pseudo-starch fragments

Rapid assembly of starch fragment analogues was achieved using 'click chemistry'. Specifically, a pentadecasaccharide and two hexadecasaccharide mimics containing two parallel maltoheptaosyl chains linked via [1,2,3]-triazoles to glucose or maltose core were synthesised using Cu(I)-catalyzed [3+2] dipolar cycloaddition of azidosaccharides and 4,6-di-O-propargylated methyl alpha-d-glucopyranoside and 6,6'- and 4',6'-di-O-propargylated p-methoxyphenyl beta-maltoside.