Structure-based design and synthesis of potent benzothiazole inhibitors of interleukin-2 inducible T cell kinase (ITK)

Inhibition of the non-receptor tyrosine kinase ITK, a component of the T-cell receptor signalling cascade, may represent a novel treatment for allergic asthma. Here we report the structure-based optimization of a series of benzothiazole amides that demonstrate sub-nanomolar inhibitory potency against ITK with good cellular activity and kinase selectivity. We also elucidate the binding mode of these inhibitors by solving the X-ray crystal structures of several inhibitor-ITK complexes.     

Predictive systems ecology

Human societies, and their well-being, depend to a significant extent on the state of the ecosystems that surround them. These ecosystems are changing rapidly usually in response to anthropogenic changes in the environment. To determine the likely impact of environmental change on ecosystems and the best ways to manage them, it would be desirable to be able to predict their future states. We present a proposal to develop the paradigm of predictive systems ecology, explicitly to understand and predict the properties and behaviour of ecological systems. We discuss the necessary and desirable features of predictive systems ecology models. There are places where predictive systems ecology is already being practised and we summarize a range of terrestrial and marine examples. Significant challenges remain but we suggest that ecology would benefit both as a scientific discipline and increase its impact in society if it were to embrace the need to become more predictive.     

Oxazolopyridines and thiazolopyridines as monoamine oxidase B inhibitors for the treatment of Parkinson’s disease

In Parkinson’s disease, the motor impairments are mainly caused by the death of dopaminergic neurons. Among the enzymes which are involved in the biosynthesis and catabolism of dopamine, monoamine oxidase B (MAO-B) has been a therapeutic target of Parkinson’s disease. However, due to the undesirable adverse effects, development of alternative MAO-B inhibitors with greater optimal therapeutic potential towards Parkinson’s disease is urgently required. In this study, we designed and synthesized the oxazolopyridine and thiazolopyridine derivatives, and biologically evaluated their inhibitory activities against MAO-B. Structure–activity relationship study revealed that the piperidino group was the best choice for the R¹ amino substituent to the oxazolopyridine core structure and the activities of the oxazolopyridines with various phenyl rings were between 267.1 and 889.5 nM in IC₅₀ values. Interestingly, by replacement of the core structure from oxazolopyrine to thiazolopyridine, the activities were significantly improved and the compound 1n with the thiazolopyridine core structure showed the most potent activity with the IC₅₀ value of 26.5 nM. Molecular docking study showed that van der Waals interaction in the human MAO-B active site could explain the enhanced inhibitory activities of thiazolopyridine derivatives.     

Synthesis and evaluation of novel azetidine analogs as potent inhibitors of vesicular [3H]dopamine uptake

Lobelane analogs that incorporate a central piperidine or pyrrolidine moiety have previously been reported by our group as potent inhibitors of VMAT2 function. Further central ring size reduction of the piperidine moiety in lobelane to a four-membered heterocyclic ring has been carried out in the current study to afford novel cis-and trans-azetidine analogs. These azetidine analogs (15a–15c and 22a–22c) potently inhibited [³H]dopamine (DA) uptake into isolated synaptic vesicles (K_i ? 66 nM). The cis-4-methoxy analog 22b was the most potent inhibitor (K_i = 24 nM), and was twofold more potent that either lobelane (2a, K_i = 45 nM) or norlobelane (2b, K_i = 43 nM). The trans-methylenedioxy analog, 15c (K_i = 31 nM), was equipotent with the cis-analog, 22b, in this assay. Thus, cis- and trans-azetidine analogs 22b and 15c represent potential leads in the discovery of new clinical candidates for the treatment of methamphetamine abuse.     

Nuclear double-fluorescent reporter for in vivo and ex vivo analyses of biological transitions in mouse nuclei

Cre-responsive dual-fluorescent alleles allow in situ marking of cell lineages or genetically modified cells. Here we report a dual-fluorescent allele, ROSA ^nT-nG , which directs nuclear accumulation of tdTomato in Cre-naïve lineages. Cre converts the allele to ROSA ^nG , which drives nuclear EGFP accumulation. Conditions were established for analyzing marked nuclei by flow cytometry on the basis of red–green fluorescence and ploidy, with a particular focus on liver nuclei. Hydrodynamic delivery of a Cre-expression plasmid was used to time-stamp arbitrary hepatocytes for lineage tracing. The distinct green fluorescence of nuclei from Cre-exposed lineages facilitated analyses of ploidy transitions within clones. To assess developmental transitions in liver nuclei, ROSA ^nT-nG was combined with the hepatocyte-specific AlbCre transgene, facilitating discrimination between hepatocyte and nonhepatocyte nuclei. Nuclei extracted from postnatal day 2 (P2) livers were 41 % green and 59 % red and reached a stable level of 84 % green by P22. Until P20, green nuclei were >98 % diploid (2N); at P40 they were ~56 % 2N, 43 % 4N, and <1 % 8N; and by P70 they reached a stable distribution of ~46 % 2N, 45 % 4N, and 9 % 8N. In conclusion, ROSA ^nT-nG will facilitate in vivo and ex vivo studies on liver and will likely be valuable for studies on tissues like muscle, kidney, or brain in which cells are refractory to whole-cell flow cytometry, or like trophectoderm derivatives or cancers in which cells undergo ploidy transitions.     

Invertebrate models of fungal infection

The morbidity, mortality and economic burden associated with fungal infections, together with the emergence of fungal strains resistant to current antimicrobial agents, necessitate broadening our understanding of fungal pathogenesis and discovering new agents to treat these infections. Using invertebrate hosts, especially the nematode Caenorhabditis elegans and the model insects Drosophila melanogaster and Galleria mellonella, could help achieve these goals. The evolutionary conservation of several aspects of the innate immune response between invertebrates and mammals makes the use of these simple hosts an effective and fast screening method for identifying fungal virulence factors and testing potential antifungal compounds. The purpose of this review is to compare several model hosts that have been used in experimental mycology to-date and to describe their different characteristics and contribution to the study of fungal virulence and the detection of compounds with antifungal properties. This article is part of a Special Issue entitled: Animal Models of Disease.     

Diverse populations of lake water bacteria exhibit chemotaxis towards inorganic nutrients

Chemotaxis allows microorganisms to rapidly respond to different environmental stimuli; however, understanding of this process is limited by conventional assays, which typically focus on the response of single axenic cultures to given compounds. In this study, we used a modified capillary assay coupled with flow cytometry and 16S rRNA gene amplicon pyrosequencing to enumerate and identify populations within a lake water microbial community that exhibited chemotaxis towards ammonium, nitrate and phosphate. All compounds elicited chemotactic responses from populations within the lake water, with members of Sphingobacteriales exhibiting the strongest responses to nitrate and phosphate, and representatives of the Variovorax, Actinobacteria ACK-M1 and Methylophilaceae exhibiting the strongest responses to ammonium. Our results suggest that chemotaxis towards inorganic substrates may influence the rates of biogeochemical processes.     

Supplementation with α-Lipoic Acid,CoQ10, and Vitamin E Augments Running Performance and Mitochondrial Function in Female Mice

Antioxidant supplements are widely consumed by the general public; however, their effects of on exercise performance are controversial. The aim of this study was to examine the effects of an antioxidant cocktail (α-lipoic acid, vitamin E and coenzyme Q10) on exercise performance, muscle function and training adaptations in mice. C57Bl/J6 mice were placed on antioxidant supplement or placebo-control diets (n = 36/group) and divided into trained (8 wks treadmill running) (n = 12/group) and untrained groups (n = 24/group). Antioxidant supplementation had no effect on the running performance of trained mice nor did it affect training adaptations; however, untrained female mice that received antioxidants performed significantly better than placebo-control mice (p ≤ 0.05). Furthermore, antioxidant-supplemented females (untrained) showed elevated respiratory capacity in freshly excised muscle fibers (quadriceps femoris) (p ≤ 0.05), reduced oxidative damage to muscle proteins (p ≤ 0.05), and increased expression of mitochondrial proteins (p ≤ 0.05) compared to placebo-controls. These changes were attributed to increased expression of proliferator-activated receptor gamma coactivator 1α (PGC-1α) (p ≤ 0.05) via activation of AMP-activated protein kinase (AMPK) (p ≤ 0.05) by antioxidant supplementation. Overall, these results indicate that this antioxidant supplement exerts gender specific effects; augmenting performance and mitochondrial function in untrained females, but does not attenuate training adaptations.