8 research outputs found
Effects of GPR139 agonism on effort expenditure for food reward in rodent models: Evidence for pro-motivational actions
Apathy, deficiency of motivation including willingness to exert effort for reward, is a common symptom in many psychiatric and neurological disorders, including depression and schizophrenia. Despite improved understanding of the neurocircuitry and neurochemistry underlying normal and deficient motivation, there is still no approved pharmacological treatment for such a deficiency. GPR139 is an orphan G protein-coupled receptor expressed in brain regions which contribute to the neural circuitry that controls motivation including effortful responding for reward, typically sweet gustatory reward. The GPR139 agonist TAK-041 is currently under development for treatment of negative symptoms in schizophrenia which include apathy. To date, however, there are no published preclinical data regarding its potential effect on reward motivation or deficiencies thereof. Here we report in vitro evidence confirming that TAK-041 increases intracellular Ca2+ mobilization and has high selectivity for GPR139. In vivo, TAK-041 was brain penetrant and showed a favorable pharmacokinetic profile. It was without effect on extracellular dopamine concentration in the nucleus accumbens. In addition, TAK-041 did not alter the effort exerted to obtain sweet gustatory reward in rats that were moderately food deprived. By contrast, TAK-041 increased the effort exerted to obtain sweet gustatory reward in mice that were only minimally food deprived; furthermore, this effect of TAK-041 occurred both in control mice and in mice in which deficient effortful responding was induced by chronic social stress. Overall, this study provides preclinical evidence in support of GPR139 agonism as a molecular target mechanism for treatment of apathy
Identifizierung der molekularen Interaktionspartner von alpha-ENaC in HepG2-Zellen: Bibliothek A (cDNAs im Vektor pPR3-N)
Optimized Target Residence Time: Typeâ Inhibitors for p38 MAP Kinase with Improved Binding Kinetics through Direct Interaction with the R-Spine
Skepinone-L was recently reported to be a p38 MAP kinase inhibitor with high potency and excellent selectivity inâ
vitro and inâ
vivo. However, this class of compounds still act as fully ATP-competitive Typeâ
I binders which, furthermore, suffer from short residence times at the enzyme. We herein describe a further development with the first Typeâ
â
binders for p38 MAP kinase. â
formula inhibitors interfere with the R-spine, inducing a glycine flip and occupying both hydrophobic regionsâ
I and II. This design approach leads to prolonged target residence time, binding to both the active and inactive states of the kinase, excellent selectivity, excellent potency on the enzyme level, and low nanomolar activity in a human whole blood assay. This promising binding mode is proven by X-ray crystallography
Targeting the Hinge Glycine Flip and the Activation Loop: Novel Approach to Potent p38α Inhibitors
The p38 MAP kinase is a key player in signaling pathways
regulating
the biosynthesis of inflammatory cytokines. Small molecule p38 inhibitors
suppress the production of these cytokines. Therefore p38 is a promising
drug target for novel anti-inflammatory drugs. In this study, we report
novel dibenzepinones, dibenzoxepines, and benzosuberones as p38α
MAP kinase inhibitors. Previously reported dibenzepinones and dibenzoxepines
were chemically modified by introduction of functional groups or removal
of a phenyl ring. This should result in targeting of the hydrophobic
region I, the âdeep pocketâ, and the hinge glycine flip
of the kinase. Potent inhibitors with IC<sub>50</sub> values in the
single digit nanomolar range (up to 3 nM) were identified. Instead
of targeting the âdeep pocketâ in the DFG-out conformation,
interactions with the DFG-motif in the in-conformation could be observed
by protein X-ray crystallography
Dibenzosuberones as p38 Mitogen-Activated Protein Kinase Inhibitors with Low ATP Competitiveness and Outstanding Whole Blood Activity
p38α mitogen-activated protein (MAP) kinase is
a main target
in drug research concerning inflammatory diseases. Nevertheless, no
inhibitor of p38α MAP kinase has been introduced to the market.
This might be attributed to the fact that there is no inhibitor which
combines outstanding activity in biological systems and selectivity.
Herein an approach to the development of such inhibitors on the basis
of the highly selective molecular probe Skepinone-L is described.
Introduction of a âdeep pocketâ moiety addressing the
DFG motif led to an increased activity of the compounds. Hydrophilic
moieties, addressing the solvent-exposed area adjacent to hydrophilic
region II, conserved a high activity of the compounds in a whole blood
assay. Combined with their outstanding selectivity and low ATP competitiveness,
these inhibitors are very interesting candidates for use in biological
systems and in therapy
Design, Synthesis, and Biological Evaluation of Novel Type I<sup>1</sup>/<sub>2</sub> p38α MAP Kinase Inhibitors with Excellent Selectivity, High Potency, and Prolonged Target Residence Time by Interfering with the RâSpine
We recently reported <b>1a</b> (skepinone-L) as a type I p38α MAP kinase inhibitor with high
potency and excellent selectivity in vitro and in vivo. However, as a type I inhibitor,
it is entirely ATP-competitive and shows just a moderate residence
time. Thus, the scope was to develop a new class of advanced compounds
maintaining the structural binding features of skepinone-L scaffold
like inducing a glycine flip at the hinge region and occupying both
hydrophobic regions I and II. Extending this scaffold with suitable
residues resulted in an interference with the kinaseâs R-Spine.
By synthesizing 69 compounds, we could significantly prolong the target
residence time with one example to 3663 s, along with an excellent
selectivity score of 0.006 and an outstanding potency of 1.0 nM. This
new binding mode was validated by cocrystallization, showing all binding
interactions typifying type I<sup>1</sup>/<sub>2</sub> binding. Moreover,
microsomal studies showed convenient metabolic stability of the most
potent, herein reported representatives
Targeting Drug Resistance in EGFR with Covalent Inhibitors: A Structure-Based Design Approach
Receptor tyrosine kinases represent one of the prime targets in cancer therapy, as the dysregulation of these elementary transducers of extracellular signals, like the epidermal growth factor receptor (EGFR), contributes to the onset of cancer, such as non-small cell lung cancer (NSCLC). Strong efforts were directed to the development of irreversible inhibitors and led to compound CO-1686, which takes advantage of increased residence time at EGFR by alkylating Cys797 and thereby preventing toxic effects. Here, we present a structure-based approach, rationalized by subsequent computational analysis of conformational ligand ensembles in solution, to design novel and irreversible EGFR inhibitors based on a screening hit that was identified in a phenotype screen of 80 NSCLC cell lines against approximately 1500 compounds. Using protein X-ray crystallography, we deciphered the binding mode in engineered cSrc (T338M/S345C), a validated model system for EGFR-T790M, which constituted the basis for further rational design approaches. Chemical synthesis led to further compound collections that revealed increased biochemical potency and, in part, selectivity toward mutated (L858R and L858R/T790M) vs nonmutated EGFR. Further cell-based and kinetic studies were performed to substantiate our initial findings. Utilizing proteolytic digestion and nano-LC-MS/MS analysis, we confirmed the alkylation of Cys797