Fragment Based Optimization of Metabotropic Glutamate Receptor 2 (mGluR2) Positive Allosteric Modulators in the Absence of Structural Information.

Metabotropic glutamate receptor 2 (mGluR2) positive allosteric modulators (PAMs) have been implicated as potential pharmacotherapy for psychiatric conditions. Screening our corporate compound deck, we identified a benzotriazole fragment (4) that was rapidly optimized to a potent and metabolically stable early lead (16). The highly lipophilic character of 16, together with its limited solubility, permeability, and high protein binding, however, did not allow reaching of the proof of concept in vivo.

Neuroblastoma GOTO cells are hypersensitive to disruption of lipid rafts.

GOTO cells, a neuroblastoma cell line retaining the ability to differentiate into neuronal or Schwann cells, were found to be rich in membrane rafts containing ganglioside GM2 and hypersensitive to lipid raft-disrupting methyl-beta-cyclodextrin (MbetaCD); the GM2-rich rafts and sensitivity to MbetaCD were markedly diminished upon their differentiation into Schwann cells. We first raised a monoclonal antibody that specifically binds to GOTO cells but not to differentiated Schwann cells and determined its target antigen as ganglioside GM2, which was shown to be highly concentrated in lipid rafts by its colocalization with flotillin, a marker protein of rafts. Disturbance of normal structure of the lipid raft by depleting its major constituent, cholesterol, with MbetaCD resulted in acute apoptotic cell death of GOTO cells, but little effects were seen on differentiated Schwann cells.

Hesr1 knockout mice exhibit behavioral alterations through the dopaminergic nervous system.

The basic helix-loop-helix (bHLH) transcriptional factor Hesr1 gene (hairy and enhancer of split-related 1, also called Hey1/HRT1/CHF2/HERP2) has been identified and characterized as a member of the subfamily of hairy/Enhancer of split, and shown to be involved in cardiovascular and neural development. We report that HESR1 binds directly to a part of the 3' non-coding region of the human dopamine transporter (DAT1) gene and represses the endogenous DAT1 gene in HEK293 cells. To investigate functions of the HESR1 gene in the dopaminergic nervous system in vivo, we analyzed the expressions of dopamine-related genes in the postnatal day 0 whole brains of Hesr1 knockout mice by real-time RT-PCR analysis.

Human neuroblastoma GOTO cells express CD44 and localize it into lipid rafts upon differentiation into Schwannian cells.

Neuroblastoma, which is a malignant tumor consisting of dedifferentiated neuroectodermal cells, is known to show spontaneous maturation or regression in its growth. Cultured human neuroblastoma GOTO cells could be induced to differentiate into Schwannian cells and neuronal cells by incubation in the presence of 5-bromo-2'-deoxyuridine (BrdU) and by serum depletion, respectively. Here we report that in association with these differentiations, cells differentiated into Schwannian cells specifically expressed a cell adhesion molecule CD44, of which expression is usually suppressed in GOTO cells.