Structure and property based design of factor Xa inhibitors: pyrrolidin-2-ones with biaryl P4 motifs

Structure and property based drug design was exploited in the synthesis of sulfonamidopyrrolidin-2-one-based factor Xa (fXa) inhibitors, incorporating biaryl P4 groups, producing highly potent inhibitors with encouraging oral pharmacokinetic profiles and significant but sub-optimal anticoagulant activities.     

Genomes2Drugs: Identifies Target Proteins and Lead Drugs from Proteome Data

Background

Genome sequencing and bioinformatics have provided the full hypothetical proteome of many pathogenic organisms. Advances in microarray and mass spectrometry have also yielded large output datasets of possible target proteins/genes. However, the challenge remains to identify new targets for drug discovery from this wealth of information. Further analysis includes bioinformatics and/or molecular biology tools to validate the findings. This is time consuming and expensive, and could fail to yield novel drugs if protein purification and crystallography is impossible. To pre-empt this, a researcher may want to rapidly filter the output datasets for proteins that show good homology to proteins that have already been structurally characterised or proteins that are already targets for known drugs. Critically, those researchers developing novel antibiotics need to select out the proteins that show close homology to any human proteins, as future inhibitors are likely to cross-react with the host protein, causing off-target toxicity effects later in clinical trials.

Methodology/Principal Findings

To solve many of these issues, we have developed a free online resource called Genomes2Drugs which ranks sequences to identify proteins that are (i) homologous to previously crystallized proteins or (ii) targets of known drugs, but are (iii) not homologous to human proteins. When tested using the Plasmodium falciparum malarial genome the program correctly enriched the ranked list of proteins with known drug target proteins.

Conclusions/Significance

Genomes2Drugs rapidly identifies proteins that are likely to succeed in drug discovery pipelines. This free online resource helps in the identification of potential drug targets. Importantly, the program further highlights proteins that are likely to be inhibited by FDA-approved drugs. These drugs can then be rapidly moved into Phase IV clinical studies under ‘change-of-application’ patents.     

The endothelial cell binding determinant of human factor IX resides in the gamma-carboxyglutamic acid domain.

The blood coagulation factor IX(a) binds specifically to a site on endothelial cells with a Kd of 2.0-3.0 nM. A number of previous studies have attempted to define the region(s) of factor IX(a) that mediate this interaction. These studies suggested that there are two regions of factor IX(a), the gamma-carboxyglutamic acid (Gla) domain and the epidermal growth factor like (EGF-like) domains, that mediate high-affinity binding to endothelial cells. Recently, however, the participation of the EGF1 domain has been excluded from the interaction. This indicated that if there was an EGF component of factor IX contributing to the binding affinity, then it must be in the second EGF-like domain. In order to further evaluate this relationship, we performed competitive binding experiments between 125I plasma factor IX and a set of six chimeric proteins composed of portions of factor VII and factor IX. Our data suggest that the high-affinity interaction between factor IX and the endothelial cell binding site is mediated by the factor IX Gla domain and that the factor IX EGF domains are not involved in binding specificity.     

Ontogenetic immune challenges shape adult personality in mallard ducks

Consistent individual differences in behaviour are widespread in animals, but the proximate mechanisms driving these differences remain largely unresolved. Parasitism and immune challenges are hypothesized to shape the expression of animal personality traits, but few studies have examined the influence of neonatal immune status on the development of adult personality. We examined how non-pathogenic immune challenges, administered at different stages of development, affected two common measures of personality, activity and exploratory behaviour, as well as colour-dependent novel object exploration in adult male mallard ducks (Anas platyrhynchos). We found that individuals that were immune-challenged during the middle (immediately following the completion of somatic growth) and late (during the acquisition of nuptial plumage) stages of development were more active in novel environments as adults relative to developmentally unchallenged birds or those challenged at an earlier developmental time point. Additionally, individuals challenged during the middle stage of development preferred orange and avoided red objects more than those that were not immune-challenged during development. Our results demonstrate that, in accordance with our predictions, early-life immune system perturbations alter the expression of personality traits later in life, emphasizing the role that developmental plasticity plays in shaping adult personality, and lending support to recent theoretical models that suggest that parasite pressure may play an important role in animal personality development.     

Attenuation of inflammation and cellular stress‐related pathways maintains insulin sensitivity in obese type I interleukin‐1 receptor knockout mice on a high‐fat diet

The development of insulin resistance in the obese is associated with chronic, low‐grade inflammation. We aimed to identify novel links between obesity, insulin resistance and the inflammatory response by comparing C57BL/6 with type I interleukin‐1 receptor knockout (IL‐1RI^?/?) mice, which are protected against diet‐induced insulin resistance. Mice were fed a high‐fat diet for 16 wk. Insulin sensitivity was measured and proteomic analysis was performed on adipose, hepatic and skeletal muscle tissues. Despite an equal weight gain, IL‐1RI^?/? mice had lower plasma glucose, insulin and triacylglycerol concentrations, compared with controls, following dietary treatment. The higher insulin sensitivity in IL‐1RI^?/? mice was associated with down‐regulation of antioxidant proteins and proteasomes in adipose tissue and hepatic soluble epoxide hydrolase, consistent with a compromised inflammatory response as well as increased glycolysis and decreased fatty acid β‐oxidation in their muscle. Their lower hepatic triacylglycerol concentrations may reflect decreased flux of free fatty acids to the liver, decreased hepatic fatty acid‐binding protein expression and decreased lipogenesis. Correlation analysis revealed down‐regulation of classical biomarkers of ER stress in their adipose tissue, suggesting that disruption of the IL‐1RI‐mediated inflammatory response may attenuate cellular stress, which was associated with significant protection from diet‐induced insulin resistance, independent of obesity.