Novel Allosteric Sites on Ras for Lead Generation

Aberrant Ras activity is a hallmark of diverse cancers and developmental diseases. Unfortunately, conventional efforts to develop effective small molecule Ras inhibitors have met with limited success. We have developed a novel multi-level computational approach to discover potential inhibitors of previously uncharacterized allosteric sites. Our approach couples bioinformatics analysis, advanced molecular simulations, ensemble docking and initial experimental testing of potential inhibitors. Molecular dynamics simulation highlighted conserved allosteric coupling of the nucleotide-binding switch region with distal regions, including loop 7 and helix 5. Bioinformatics methods identified novel transient small molecule binding pockets close to these regions and in the vicinity of the conformationally responsive switch region. Candidate binders for these pockets were selected through ensemble docking of ZINC and NCI compound libraries. Finally, cell-based assays confirmed our hypothesis that the chosen binders can inhibit the downstream signaling activity of Ras. We thus propose that the predicted allosteric sites are viable targets for the development and optimization of new drugs

Counseling in Audiology, or Learning to Listen: Pre- and Post-Measures from an Audiology Counseling Course

Because of a technology explosion, audiologists have more options than ever in providing for their patients\u27 hearing needs. However, relatively few individuals with hearing loss seek out amplification, and those who do frequently report dissatisfaction with the quality of their interactions with audiologists. Most audiologists did not have coursework in counseling in their graduate programs, which may account for patient complaints. As part of a course development evaluation of an audiology counseling course, a preliminary study was conducted to examine two student learning objectives: to learn how to differentiate between content messages and affective messages and to learn how to respond to each type of message appropriately. Pre- and postcourse data collected from two cohorts of audiology graduate students indicated that (a) before taking the course, students were likely to provide informational responses to personal adjustment comments (a type of communication mismatch ), and (b) at the end of the class, they were much more likely to match or mirror affective statements with affective responses

On the Origin of the Stronger Binding of PIB over Thioflavin T to Protofibrils of the Alzheimer Amyloid-β Peptide: A Molecular Dynamics Study

Pittsburgh compound B (PIB) is a neutral derivative of the fluorescent dye Thioflavin T (ThT), which displays enhanced hydrophobicity and binding affinity to amyloid fibrils. We present molecular dynamics simulations of binding of PIB and ThT to a common cross-β-subunit of the Alzheimer Amyloid-β peptide (Aβ). Our simulations of binding to Aβ9-40 protofibrils show that PIB, like ThT, selectively binds to the hydrophobic or aromatic surface grooves on the β-sheet surface along the fibril axis. The lack of two methyl groups and charge in PIB not only improves its hydrophobicity but also leads to a deeper insertion of PIB compared to ThT into the surface grooves. This significantly increases the steric, aromatic, and hydrophobic interactions, and hence leads to stronger binding. Simulations on protofibrils consisting of the more-toxic Aβ17-42 revealed an additional binding mode in which PIB and ThT insert into the channel that forms in the loop region of the protofibril, sandwiched between two sheet layers. Our simulations indicate that the rotation between the two ring parts of the dyes is significantly more restricted when the dyes are bound to the surface of the cross-β-subunits or to the channel inside the Aβ17-42 cross-β-subunit, compared with free solution. The specific conformations of the dyes are influenced by small chemical modifications (ThT versus PIB) and by the environment in which the dye is placed

Discovery of novel human Aquaporin-1 Blockers

Human aquaporin-1 (hAQP1) is a water channel found in many tissues and potentially involved in several human pathologies. Selective inhibitors of hAQP1 are discussed as novel treatment opportunities for glaucoma, brain edema, inflammatory pain, and certain types of cancer. However, only very few potent and chemically attractive blockers have been reported to date. In this study we present three novel hAQP1 blockers that have been identified by virtual screening and inhibit water flux through hAQP1 in Xenopus laevis oocyte swelling assays at low micromolar concentrations. The newly discovered compounds display no chemical similarity to hitherto known hAQP1 blockers and bind at the extracellular entrance of the channel, close to the ar/R selectivity filter. Futhermore, mutagenesis studies showed that Lys36, which is not conserved among the hAQP family, is crucially involved in binding and renders the discovered compounds suitable as leads for the development of selective hAQP1 inhibitors. © 2012 American Chemical SocietyPeer Reviewe