Novel analogs of D-e-MAPP and B13. Part 1: synthesis and evaluation as potential anticancer agents

A series of novel isosteric analogs of the ceramidase inhibitors, (1S,2R)-N-myristoylamino-phenylpropanol-1 (d-e-MAPP) and (1R,2R)-N-myristoylamino-4'-nitro-phenylpropandiol-1,3 (B13), with modified targeting and physicochemical properties were designed, synthesized, and evaluated as potential anticancer agents. When MCF7 cells were treated with the analogs, results indicated that the new analogs were of equal or greater potency compared to the parent compounds. Their activity was predominantly defined by the nature of the modification of the N-acyl hydrophobic interfaces: N-acyl analogs (class A), urea analogs (class B), N-alkyl analogs (class C, lysosomotropic agents), and omega-cationic-N-acyl analogs (class D, mitochondriotropic agents). The most potent compounds belonged to either class D, the aromatic ceramidoids, or to class C, the aromatic N-alkylaminoalcohols. Representative analogs selected from this study were also evaluated by the National Cancer Institute In Vitro Anticancer Drug Discovery Screen. Again, results showed a similar class-dependent activity. In general, the active analogs were non-selectively broad spectrum and had promising activity against all cancer cell lines. However, some active analogs of the d-e-MAPP family were selective against different types of cancer. Compounds LCL85, LCL120, LCL385, LCL284, and LCL204 were identified to be promising lead compounds for therapeutic development.     

Survey for Zoonotic Microsporidian Pathogens in Wild Living Urban Rooks (Corvus frugilegus)

Microsporidia are opportunistic pathogens in nature infecting all animal phyla. There is a potential risk of microsporidian spores transmission from urban rooks inhabiting some metropolitan cities to people through casual interactions. The aim of this study was to identify microsporidia species in the droppings of rooks in Wroclaw, Poland. A total of 15 collective sets of droppings were examined using nested‐PCR method. Amplification of ITS rRNA gene revealed the presence of Enterocytozoon bieneusi D, Peru 6, and Encephalitozoon hellem 1A genotypes. This study indicates that excreta of urban rooks can be an important source of human infection with these pathogens.     

Ceramide 1-phosphate acts as a positive allosteric activator of group IVA cytosolic phospholipase A2 alpha and enhances the interaction of the enzyme with phosphatidylcholine

Previous findings from our laboratory have demonstrated that cPLA(2)alpha is directly activated by the emerging bioactive sphingolipid, ceramide 1-phosphate (C-1-P) (1). In this study, a Triton X-100/phosphatidylcholine (PC) mixed micelle assay was utilized to determine the kinetics and specificity of this lipid-enzyme interaction. Using this assay, the addition of C-1-P induced a dramatic increase in the activity of cPLA(2)alpha (>15-fold) with a K(a) of 2.4 mol % C-1-P/Triton X-100 micelle. This activation was highly specific as the addition of other lipids had insignificant effects on cPLA(2)alpha activity. Studies using surface-dilution kinetics revealed that C-1-P had no effect on the Michaelis-Menten constant, K(m)(B), but decreased the dissociation constant (K (A)(s)) value by 87%. Thus, C-1-P not only increases the membrane affinity of cPLA(2)alpha but also may act as an allosteric activator of the enzyme. Surface plasmon resonance analysis of the C-1-P/cPLA(2)alpha interaction verified a decrease in the dissociation constant, demonstrating that cPLA(2)alpha bound PC vesicles containing C-1-P with increased affinity (5-fold) compared with PC vesicles alone. The effect on the dissociation rate of cPLA(2)alpha was also found to be lipid-specific with the exception of phosphatidylinositol 4,5-bisphosphate, which caused a modest increase in vesicle affinity (2-fold). Lastly, the binding site for C-1-P was determined to be within the C2-domain of cPLA(2)alpha, unlike phosphatidylinositol 4,5-bisphosphate. These data demonstrate a novel interaction site for C-1-P and suggest that C-1-P may function to recruit cPLA(2)alpha to intracellular membranes as well as allosterically activate the membrane-associated enzyme.     

Loss of ecto-5'nucleotidase from porcine endothelial cells after exposure to human blood: Implications for xenotransplantation

The endothelial cell surface expression of ecto-5'-nucleotidase (E5'N, CD73) is thought to be essential for the extracellular formation of cytoprotective, anti-thrombotic and immunosuppressive adenosine. Decreased E5'N activity may play a role in xenograft acute vascular rejection, preventing accommodation and tolerance mechanisms. We investigated the extent of changes in E5'N activity and other enzymes of purine metabolism in porcine hearts or endothelial cells when exposed to human blood or plasma and studied the role of humoral immunity in this context. Pig hearts, wild type (WT, n = 6) and transgenic (T, n = 5) for human decay accelerating factor (hDAF), were perfused ex vivo with fresh human blood for 4 h. Pig aortic endothelial cells (PAEC) were exposed for 3 h to autologous porcine plasma (PP), normal (NHP) or heat inactivated human plasma (HHP), with and without C1-inhibitor. Enzyme activities were measured in heart or endothelial cell homogenates with an HPLC based procedure. The baseline activity of E5'N in WT and T porcine hearts were 6.60 +/- 0.33 nmol/min/mg protein and 8.54 +/- 2.10 nmol/min/mg protein respectively (P < 0.01). Ex vivo perfusion of pig hearts with fresh human blood for 4 h resulted in a decrease in E5'N activity to 4.01 +/- 0.32 and 4.52 +/- 0.52 nmol/min/mg protein (P < 0.001) in WT and T hearts respectively, despite attenuation of hyperacute rejection in transgenic pigs. The initial PAEC activity of E5'N was 9.10 +/- 1.40 nmol/min/mg protein. Activity decreased to 6.76 +/- 0.57 and 4.58 +/- 0.47 nmol/min/mg protein (P < 0.01) after 3 h exposure of HHP and NHP respectively (P < 0.05), whereas it remained unchanged at 9.62 +/- 0.88 nmol/min/mg protein when incubated with PP controls. C1-inhibitor partially preserved E5'N activity, similar to the effect of HHP. Adenosine deaminase, adenosine kinase and AMP deaminase (other enzymes of purine metabolism) showed a downward trend in activity, but none were statistically significant. We demonstrate a specific decrease in E5'N activity in pig hearts following exposure to human blood which impairs adenosine production resulting in a loss of a cytoprotective phenotype, contributing to xenograft rejection. This effect is triggered by human humoral immune responses, and complement contributes but does not fully mediate E5'N depletion.     

Effect of donor stimulation, frozen semen and heparin treatment on the efficiency of in vitro embryo production in goats

Investigations on in vitro embryo production in goats in comparison with other domestic species, especially cattle, have been the subject of few reports despite their usefulness for both basic research and commercial application. The objectives of this study were to compare the efficiency of IVP in goats using immature follicular oocytes recovered from FSH-primed and control goats. After IVM, oocytes were fertilized with fresh or frozen-thawed semen capacitated with or without heparin. Mature oocytes were fertilized in vitro with fresh and frozen-thawed sperm of a single buck. Sperm preparation included swim-up separation and heparin treatment (50 micrograms/ml of sperm suspension for 45 min) before spermatozoa were added to oocytes in TALP-IVF. After IVF, the zygotes were cultured for 24h and cleaved embryos were further cultured with goat oviduct epithelial cells or transferred to synchronized recipients. Mean number of oocytes recovered from FSH-primed goats (24.5 +/- 8.6) was significantly higher (P < 0.01; t test) in comparison to control does (14.7 +/- 4.7). Irrespective of fresh or frozen semen, no differences were observed in blastocyst yield when sperm was treated with heparin. However, the highest cleavage rate (99/126; 79.4%) as well as blastocyst yield (47/126; 37.3%) was obtained after IVF with fresh sperm capacitated without heparin. Contrary to fresh sperm, heparin treatment of frozen-thawed sperm significantly improved (P < 0.01) embryo cleavage. No differences between in vivo developmental competence of embryos related to sperm origin were found after transferring into recipients. Overall, more than 60% of the recipients became pregnant and 20% of all transferred embryos survived delivering 13 healthy kids. Our caprine IVP system allows obtaining embryos with developmental competence comparable to bovine IVP.     

Plasmon-waveguide resonance studies of lateral segregation of lipids and proteins into microdomains (rafts) in solid-supported bilayers

Plasmon-waveguide resonance (PWR) spectroscopy has been used to examine solid-supported lipid bilayers consisting of dioleoylphosphatidylcholine (DOPC), palmitoyloleoylphosphatidylcholine (POPC), sphingomyelin (SM), and phosphatidylcholine/SM binary mixtures. Spectral simulation of the resonance curves demonstrated an increase in bilayer thickness, long-range order, and molecular packing density in going from DOPC to POPC to SM single component bilayers, as expected based on the decreasing level of unsaturation in the fatty acyl chains. DOPC/SM and POPC/SM binary mixtures yielded PWR spectra that can be ascribed to a superposition of two resonances corresponding to microdomains (rafts) consisting of phosphatidylcholine- and SM-rich phases coexisting within a single bilayer. These were formed spontaneously over time as a consequence of lateral phase separation. Each microdomain contained a small proportion (<20%) of the other lipid component, which increased their kinetic and thermodynamic stability. Incorporation of a glycosylphosphatidylinositol-linked protein (placental alkaline phosphatase) occurred within each of the single component bilayers, although the insertion was less efficient into the DOPC bilayer. Incorporation of placental alkaline phosphatase into a DOPC/SM binary bilayer occurred with preferential insertion into the SM-rich phase, although the protein incorporated into both phases at higher concentrations. These results demonstrate the utility of PWR spectroscopy to provide insights into raft formation and protein sorting in model lipid membranes.     

Automating parallel peptide synthesis for the production of PNA library arrays.

A system was establishedfor the parallel synthesis of peptide library arrays in afully automated manner Synthesis takes place in blocks made of polyoxymethylene that hold during all synthesis steps a polypropylene membrane of 8 x 12 cm. Yields are in the nanomole range, obtained at a low consumption of reagents. The current setup is based on a commercially available pipetting robot and supports the generation of 1536 different oligomers/run. Much higher array densities are possible because the membranes are amicable to spot diameters of down to 200 microm, naturally at a cost of the absolute amount produced of each oligomer The method was put to use for the creation of arrayed libraries of peptide nucleic acids (PNAs). These can be employed both as a source of PNA molecules applied individually in experimentation subsequent to their release or as intact oligomer arrays in hybridization analyses.     

Novel carbohydrate binding modules in the surface anchored α‐amylase of Eubacterium rectale provide a molecular rationale for the range of starches used by this organism in the human gut

Gut bacteria recognize accessible glycan substrates within a complex environment. Carbohydrate binding modules (CBMs) of cell surface glycoside hydrolases often drive binding to the target substrate. Eubacterium rectale, an important butyrate‐producing organism in the gut, consumes a limited range of substrates, including starch. Host consumption of resistant starch increases the abundance of E. rectale in the intestine, likely because it successfully captures the products of resistant starch degradation by other bacteria. Here, we demonstrate that the cell wall anchored starch‐degrading α‐amylase, Amy13K of E. rectale harbors five CBMs that all target starch with differing specificities. Intriguingly these CBMs efficiently bind to both regular and high amylose corn starch (a type of resistant starch), but have almost no affinity for potato starch (another type of resistant starch). Removal of these CBMs from Amy13K reduces the activity level of the enzyme toward corn starches by ～40‐fold, down to the level of activity toward potato starch, suggesting that the CBMs facilitate activity on corn starch and allow its utilization in vivo. The specificity of the Amy13K CBMs provides a molecular rationale for why E. rectale is able to only use certain starch types without the aid of other organisms.     

The influence of coal ashes and soil dust on the activity of two selected hydrolytic enzymes in the liver of laboratory animals

The effect of a single intratracheal application of the electroenergetic ashes and the soil dust on the liver cell was studied by means of the histoenzymatic methods for the determination of the activities of chosen hydrolases (AcP, E.C. 3.1.3.2. and ATP, E.C. 3.6.1.). The degree of the histochemical changes in hepatocytes depended on the kind of the applied dust and the trace elements' content in it. The activity's increase of the acid phosphatase and ATP-ase in each experimental group was observed, especially in the preparations collected from the animals were given the electroenergetic ashes.     

Polymorphism in exon 6 of the human NT5E gene is associated with aortic valve calcification

ABSTRACT

NT5E encodes ecto-5′-nucleotidase (e5NT, CD73) which hydrolyses extracellular AMP to adenosine. Adenosine has been shown to play a protective role against aortic valve calcification (AVC). We identified two nonsynonymous missense single nucleotide polymorphisms (c.1126A > G, p.T376A and c.1136T > C, p.M379T) in exon 6 of the human NT5E gene. Since both substitutions might affect e5NT activity and consequently alter extracellular adenosine levels, we evaluated the association between NT5E alleles and calcific aortic valve disease in 119 patients (95 patients with AVC and 24 controls). In AVC patients, the frequency of the G allele at c.1126 and the frequency of the GG genotype as well as the frequency of the C allele at c.1136, and the frequencies of CC and TC genotypes tended to be higher as compared to controls. The allele and genotype frequencies in AVC patients and controls were also compared to those calculated from the 1000 Genomes Project data for control individuals of European ancestry (n = 503). We found that the frequency of the C allele at c.1136 is significantly higher in patients with AVC than in the European controls (0.111 vs. 0.054, P = 0.0052). Moreover, e5NT activity in aortic valves showed a trend toward lower levels in AVC patients with CC and TC genotypes than in those with the TT genotype. Our findings indicate that the genetic polymorphism of NT5E may contribute to the pathogenesis of calcific aortic valve disease and that the C allele of SNP c.1136 is associated with an increased risk of AVC.