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Witkin J.M.,Discovery Labs
CNS & neurological disorders drug targets | Year: 2013

Curcumin, the major constituent of the spice tumeric produces a plethora of biological actions that have translated in vivo into behavioral and neurochemical effects in rodents that are also produced by clinically-used antidepressants. The present study was designed to provide a systematic replication of prior behavioral, pharmacological, and neurochemical experiments. In particular, the ability of curcumin to engender anti-immobility effects in the mouse forced-swim assay was established. Although prior work had shown curcumin to function as an inhibitor of the monoamine metabolizing enzyme, monoamine oxidase (MAO), neither MAOA nor MAOB was inhibitied by curcumin in the present study. Curcumin had also been reported previously to function as a cannabinoid CB1 receptor inverse agonist/antagonist. However, in our hands, curcumin did not potently alter GTP-γ.-35S binding indicative of functional CB1 antagonism (Kb = 2080 nM). Moreover, curcumin was not able to prevent the hypothermic effects of the cannabinoid receptor agonist (-)-cis-3-[2-Hydroxy-4-(1,1-dimethylheptyl)phenyl]-trans-4-(3-hydroxypropyl)cyclohexanol (CP 55,940). Nonetheless, the anti-immobility effects of curcumin did not occur in CB1 -/- mice. Finally, a broad array of protein receptors and enzymes were evaluated in vitro for their potential interaction with and/or functional engagement with curcumin. Of the more than 100 targets screened, curcumin had very low potency in most. Of those targets with appreciable activity, curcumin had affinities for the human cloned muscarinic receptor subtypes (Ki = 1.3-3.1 uM). Moreover, the plasma and brain levels of curcumin at behaviorally-active doses were below quantitative limits. Given these findings, it is concluded that the prominent antidepressant-like behavioral effects of curcumin, replicated here and in multiple acute and chronic rodent models detailed in the literature, are the result of as yet undisclosed mechanisms of action. The scientific and patient communities await the full scale clinical evaluation of a sufficiently bioavailable curcumin analog in major depressive disorder.

Rauen K.A.,University of California at San Francisco | Banerjee A.,University of California at San Francisco | Bishop W.R.,Discovery Labs | Lauchle J.O.,University of California at San Francisco | And 8 more authors.
American Journal of Medical Genetics, Part C: Seminars in Medical Genetics | Year: 2011

The RASopathies, one of the largest groups of multiple congenital anomaly syndromes known, are caused by germline mutations in various genes encoding components of the Ras/mitogen-activated protein kinase (MAPK) pathway. The RASopathies have many overlapping characteristics, including craniofacial manifestations, cardiac malformations, cutaneous, musculoskeletal, gastrointestinal, and ocular abnormalities, neurocognitive impairment, hypotonia, and an increased risk of developing cancer. Costello syndrome (CS) and cardio-facio-cutaneous (CFC) syndrome are two of the more rare RASopathies. CS is caused by activating mutations in HRAS, and CFC is caused by dysregulation of signaling in the Ras/MAPK pathway due to mutations in BRAF, MEK1, or MEK2. The Ras/MAPK pathway, which has been well-studied in cancer, is an attractive target for inhibition in the treatment of various malignancies utilizing small molecule therapeutics that specifically inhibit the pathway. With many inhibitors of the Ras/MAPK pathway in clinical trials, the notion of using these molecules to ameliorate developmental defects in CS and CFC is under consideration. CS and CFC, like other syndromes in their class, have a progressive phenotype and may be amenable to inhibition or normalization of signaling. © 2011 Wiley-Liss, Inc.

Smith D.D.,Discovery Labs
2015 IEEE Compound Semiconductor Integrated Circuit Symposium, CSICS 2015 | Year: 2015

A new oscillation mode has been observed in bulk planar InP Gunn diode devices with integrated metallic gratings. The grating mode oscillation is distinct from the transit mode of normal Gunn diodes. Its characteristics depend on doping concentration: In 1e17/cc material, the grating mode is consistent with the Smith-Purcell mode [1]. In 5e16/cc material, the grating-mode frequency is 5-10 times higher than the transit frequency with comparable power. It is currently believed that the low-doped mode is attributable to the limited-space-charge accumulation (LSA) mode. This work has led to new design concepts which are expected to result in robust 100-300GHz sources by 2016. © 2015 IEEE.

Jansen J.M.,Novartis | Cornell W.,Discovery Labs | Tseng Y.J.,National Taiwan University | Amaro R.E.,University of California at San Diego
Journal of Molecular Graphics and Modelling | Year: 2012

Teach-Discover-Treat (TDT) is an initiative to promote the development and sharing of computational tools solicited through a competition with the aim to impact education and collaborative drug discovery for neglected diseases. Collaboration, multidisciplinary integration, and innovation are essential for successful drug discovery. This requires a workforce that is trained in state-of-the-art workflows and equipped with the ability to collaborate on platforms that are accessible and free. The TDT competition solicits high quality computational workflows for neglected disease targets, using freely available, open access tools. © 2012 Elsevier Inc.

Chetty S.,University of California at Berkeley | Chetty S.,Harvard Stem Cell Institute | Friedman A.R.,University of California at Berkeley | Taravosh-Lahn K.,University of California at Berkeley | And 18 more authors.
Molecular Psychiatry | Year: 2014

Stress can exert long-lasting changes on the brain that contribute to vulnerability to mental illness, yet mechanisms underlying this long-term vulnerability are not well understood. We hypothesized that stress may alter the production of oligodendrocytes in the adult brain, providing a cellular and structural basis for stress-related disorders. We found that immobilization stress decreased neurogenesis and increased oligodendrogenesis in the dentate gyrus (DG) of the adult rat hippocampus and that injections of the rat glucocorticoid stress hormone corticosterone (cort) were sufficient to replicate this effect. The DG contains a unique population of multipotent neural stem cells (NSCs) that give rise to adult newborn neurons, but oligodendrogenic potential has not been demonstrated in vivo. We used a nestin-CreER/YFP transgenic mouse line for lineage tracing and found that cort induces oligodendrogenesis from nestin-expressing NSCs in vivo. Using hippocampal NSCs cultured in vitro, we further showed that exposure to cort induced a pro-oligodendrogenic transcriptional program and resulted in an increase in oligodendrogenesis and decrease in neurogenesis, which was prevented by genetic blockade of glucocorticoid receptor (GR). Together, these results suggest a novel model in which stress may alter hippocampal function by promoting oligodendrogenesis, thereby altering the cellular composition and white matter structure. © 2014 Macmillan Publishers Limited.

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