Design, synthesis, and testing of an 6-O-linked series of benzimidazole based inhibitors of CDK5/p25

Alzheimer’s disease (AD) is a progressive neurodegenerative disease resulting in cognitive and behavioral impairment. The two classic pathological hallmarks of AD include extraneuronal deposition of amyloid ?? (A??) and intraneuronal formation of neurofibrillary tangles (NFTs). NFTs contain hyperphosphorylated tau. Tau is the major microtubule-associated protein in neurons and stabilizes microtubules (MTs). Cyclin dependent kinase 5 (CDK5), when activated by the regulatory binding protein p25, phosphorylates tau at a number of proline-directed serine/threonine residues, resulting in formation of phosphorylated tau as paired helical filaments (PHFs) then in subsequent deposition of PHFs as NFTs. Beginning with the structure of Roscovitine, a moderately selective CDK5 inhibitor, we sought to conduct structural modifications to increase inhibitory potency of CDK5 and increase selectivity over a similar enzyme, cyclin dependent kinase 2 (CDK2). The design, synthesis, and testing of a series of 1-isopropyl-4-aminobenzyl-6-ether-linked benzimidazoles is presented.     

Human metabolic phenotypes link directly to specific dietary preferences in healthy individuals

Individual human health is determined by a complex interplay between genes, environment, diet, lifestyle, and symbiotic gut microbial activity. Here, we demonstrate a new "nutrimetabonomic" approach in which spectroscopically generated metabolic phenotypes are correlated with behavioral/psychological dietary preference, namely, "chocolate desiring" or "chocolate indifferent". Urinary and plasma metabolic phenotypes are characterized by differential metabolic biomarkers, measured using 1H NMR spectroscopy, including the postprandial lipoprotein profile and gut microbial co-metabolism. These data suggest that specific dietary preferences can influence basal metabolic state and gut microbiome activity that in turn may have long-term health consequences to the host. Nutrimetabonomics appears as a promising approach for the classification of dietary responses in populations and personalized nutritional management.     

Human keratinocytes acquire cellular cytotoxicity under UV-B irradiation. Implication of granzyme B and perforin

Ultraviolet (UV) radiation from the sun is widely considered as a major cause of human skin photoaging and skin cancer. Granzyme B (GrB) and perforin (PFN) are two proteins contained in granules and implicated in one of the mechanisms by which cytotoxic lymphocytes and natural killer cells exert their cytotoxicity against virus-infected, alloreactive, or transformed cells. The distribution of GrB and PFN in the skin has received little attention. However, Berthou and co-workers (Berthou, C., Michel, L., Soulie, A., Jean-Louis, F., Flageul, B., Dubertret, L., Sigaux, F., Zhang, Y., and Sasportes, M. (1997) J. Immunol. 159, 5293-5300) described that, whereas freshly isolated epidermal cells did not express GrB or PFN, keratinocyte growth to confluence was associated with GrB and PFN mRNA and protein synthesis. In this work, we have investigated the possible role of UV-B on GrB and PFN expression in keratinocytes. We found that UV-B induces GrB and PFN expression in these cells through redox-, epidermal growth factor receptor-, and mitogen-activated protein kinase-dependent signaling. Furthermore, under UV irradiation, keratinocytes acquire a significant cytotoxicity, which is GrB and PFN dependent, toward a variety of cellular targets including transformed T-lymphocytes, melanocytes, and keratinocytes. This phenomenon may have important functional consequences in the regulation of skin inflammatory response and in the emergence of cancer skin.     

Arsenic degrades PML or PML-RARalpha through a SUMO-triggered RNF4/ubiquitin-mediated pathway

In acute promyelocytic leukaemia (APL), arsenic trioxide induces degradation of the fusion protein encoded by the PML-RARA oncogene, differentiation of leukaemic cells and produces clinical remissions. SUMOylation of its PML moiety was previously implicated, but the nature of the degradation pathway involved and the role of PML-RARalpha catabolism in the response to therapy have both remained elusive. Here, we demonstrate that arsenic-induced PML SUMOylation triggers its Lys 48-linked polyubiquitination and proteasome-dependent degradation. When exposed to arsenic, SUMOylated PML recruits RNF4, the human orthologue of the yeast SUMO-dependent E3 ubiquitin-ligase, as well as ubiquitin and proteasomes onto PML nuclear bodies. Arsenic-induced differentiation is impaired in cells transformed by a non-degradable PML-RARalpha SUMOylation mutant or in APL cells transduced with a dominant-negative RNF4, directly implicating PML-RARalpha catabolism in the therapeutic response. We thus identify PML as the first protein degraded by SUMO-dependent polyubiquitination. As PML SUMOylation recruits not only RNF4, ubiquitin and proteasomes, but also many SUMOylated proteins onto PML nuclear bodies, these domains could physically integrate the SUMOylation, ubiquitination and degradation pathways.     

HGF/SF Induces Mesothelial Cell Migration and Proliferation by Autocrine and Paracrine Pathways

Mesothelial repair differs from that of other epithelial-like surfaces as healing does not occur solely by centripetal in-growth of cells as a sheet from the wound margins. Mesothelial cells lose their cell-cell junctions, divide, and adopt a fibroblast-like morphology while scattering across and covering the wound surface. These features are consistent with a cellular response to hepatocyte growth factor/scatter factor (HGF/SF). In this study, we examined the ability of mesothelial cells to secrete HGF/SF and investigated its possible role as an autocrine regulator of mesothelial cell motility and proliferation. We found that human primary mesothelial cells expressed HGF/SF mRNA and secreted active HGF/SF into conditioned medium as determined by ELISA and in a scattering bioassay. These cells also expressed the HGF/SF receptor, Met, as shown by RT-PCR and by Western blot analysis and immunofluorescence. Incubation of mesothelial cells with neutralizing antibodies to HGF/SF decreased cell migration to 25% of controls, whereas addition of HGF/SF disrupted cell-cell junctions and induced scattering and enhanced mesothelial cell migration. Furthermore, HGF/SF showed a small but significant mitogenic effect on all mesothelial cell lines examined. In conclusion, HGF/SF is produced by mesothelial cells and induces both motility and proliferation of these cells. These data are consistent with HGF/SF playing an autocrine role in mesothelial healing.     

Preserved functional specialization for spatial processing in the middle occipital gyrus of the early blind

The occipital cortex (OC) of early-blind humans is activated during various nonvisual perceptual and cognitive tasks, but little is known about its modular organization. Using functional MRI we tested whether processing of auditory versus tactile and spatial versus nonspatial information was dissociated in the OC of the early blind. No modality-specific OC activation was observed. However, the right middle occipital gyrus (MOG) showed a preference for spatial over nonspatial processing of both auditory and tactile stimuli. Furthermore, MOG activity was correlated with accuracy of individual sound localization performance. In sighted controls, most of extrastriate OC, including the MOG, was deactivated during auditory and tactile conditions, but the right MOG was more activated during spatial than nonspatial visual tasks. Thus, although the sensory modalities driving the neurons in the reorganized OC of blind individuals are altered, the functional specialization of extrastriate cortex is retained regardless of visual experience.     

Antimicrobial peptides from the skin of the Tsushima brown frog Rana tsushimensis

The Tsushima brown frog Rana tsushimensis Stejneger, 1907 exists in reproductive isolation on the island of Tsushima, Japan. Six peptides with antimicrobial activity were isolated in pure form from an extract of the skin of this species and their amino acid sequences identified them as members of the brevinin-1 (one peptide), brevinin-2 (one peptide) and temporin (four peptides) families. The C-terminally alpha-amidated brevinin-1 peptide (FLGSIVGALASALPSLISKIRN.NH2) lacks the cyclic heptapeptide domain Cys18-(Xaa)4-Lys-Cys24 at the COOH-terminus of the molecule that characterizes other members of that family. A structurally similar brevinin-1 peptide, also lacking the cyclic domain, was previously isolated from the skin of the Ryukyu brown frog Rana okinavana, indicative of a close phylogenetic relationship between the species. Brevinin-2TSa (GIMSLFKGVLKTAGKHVAGSLVDQLKCKITGGC) showed broad-spectrum growth inhibitory activity against a range of Gram-negative and Gram-positive bacteria (including methicillin-resistant Staphylococcus aureus) (minimum inhibitory concentrations< or =25 microM) and relatively low hemolytic activity against human erythrocytes (LD50=100 microM). The peptide therefore represents a candidate for drug development.     

Genotypic variation in the response of two perennial grass species to elevated carbon dioxide

Shoot and reproductive biomass of genotypes of Bromus erectus and Dactylis glomerata grown in competition at ambient and elevated CO₂ were examined for 2 consecutive years in order to test whether genetic variation in those traits exists and whether it is maintained over time. At the species level, a positive CO₂ response of shoot biomass of both species was only found in the first year of treatment. At the genotype level, no significant CO₂2genotype interaction was found at any single harvest either for vegetative or reproductive biomass of either species. Analysis over time, however, indicated that there is a potential for evolutionary adaptation only for D. glomerata: (1) repeated measures ANOVA detected a marginally significant CO₂2genotype2time interaction for shoot biomass, because the range of the genotypes CO₂ response increased over time; (2) genotypes that displayed the highest response during the first year under elevated CO₂ also showed the highest response the second year. Null (B. erectus) or weak (D. glomerata) selective potentials of elevated CO₂ were detected in this experiment, but short time series could underestimate this potential with perennial species.     

Nutritional metabonomics: applications and perspectives

Nowadays, nutrition focuses on improving health of individuals through diet. Current nutritional research aims at health promotion, disease prevention, and performance improvement. Modern analytical platforms allow the simultaneous measurement of multiple metabolites providing new insights in the understanding of the functionalities of cells and whole organisms. Metabonomics, "the quantitative measurement of the dynamic multiparametric metabolic response of living systems to pathophysiological stimuli or genetic modifications", provides a systems approach to understanding global metabolic regulations of organisms. This concept has arisen from various applications of NMR and MS spectroscopies to study the multicomponent metabolic composition of biological fluids, cells, and tissues. The generated metabolic profiles are processed by multivariate statistics to maximize the recovery of information to be correlated with well-determined stimuli such as dietary intervention or with any phenotypic data or diet habits. Metabonomics is thus uniquely suited to assess metabolic responses to deficiencies or excesses of nutrients and bioactive components. Furthermore, metabonomics is used to characterize the metabolic phenotype of individuals integrating genetic polymorphism, metabolic interactions with commensal and symbiotic partners such as gut microflora, as well as environmental and behavioral factors including dietary preferences. This paper reports several experimental key aspects in nutritional metabonomics, reviews its applications employing targeted and holistic approach analysis for the study of the metabolic responses following dietary interventions. It also reports the assessment of intra- and inter-individual variability in animal and human populations. The potentialities of nutritional metabonomics for the discovery of new biomarkers and the characterization of metabolic phenotypes are discussed in a context of their possible utilizations for personalized nutrition to provide health maintenance at the individual level.