Dorit Ron, Ph.D., Director
The goal of this component is to study the role of the small G protein H-Ras in ethanol's action.
Previously the Ron lab found that the activity of H-Ras is increased upon ethanol exposure in the
hippocampus (Suvarna et al., 2004), and in the reward pathway. Furthermore, activation of H-Ras
contributes to the inhibitory actions of ethanol on the activity of the N-Methyl-D-Asparate receptor,
one of the main targets of ethanol in the brain. Systemic administration of a dominant negative form
of H-Ras decreased voluntary ethanol, but not water, intake. Interestingly, the H-Ras transcript
was recently shown to be up-regulated in brains of selected lines of mice that consume high levels
of ethanol (Mulligan et al., 2006). These findings led to the hypothesis that H-Ras plays an important
role in neuroadaptations that underlie behaviors associated with ethanol exposure, such as ethanol
drinking behaviors. This component is using a virus-mediated gene delivery approach to down-regulate
and up-regulate the level and activity of H-Ras in the reward pathway, and testing for possible
molecular, electrophysiological and behavioral consequences of ethanol-mediated activation of H-Ras.
In addition, the investigators are using similar approaches to test for possible mechanisms that
lead to the activation of H-Ras by ethanol.
Ras inhibitors are currently being developed by the pharmaceutical industry as potential drugs for the
treatment of cancer. Therefore, results obtained from these experiments could lead to rapid development
of new medications to treat alcohol addiction. Furthermore, Ras is a focal point in various signaling
cascades to be investigated within the ACTG (i.e., Component 7 - Tao kinases, Pilot Project 9B - Puckered
MAP kinase phosphatase and Pilot Project 9B - atypical PKCs).
Ethanol alters trafficking and functional N-methyl-D-aspartate receptor NR2 subunit ratio via H-Ras.
Suvarna N, Borgland SL, Wang J, Phamluong K, Auberson YP, Bonci A, Ron D. J Biol Chem. 2005 Sep 9;280(36):31450-9.
Toward understanding the genetics of alcohol drinking through transcriptome meta-analysis.
Mulligan MK, Ponomarev I, Hitzemann RJ, Belknap JK, Tabakoff B, Harris RA, Crabbe JC, Blednov YA, Grahame NJ, Phillips TJ, Finn DA, Hoffman PL, Iyer VR, Koob GF, Bergeson SE. Proc Natl Acad Sci U S A. 2006 Apr 18;103(16):6368-73.
F. Woodward Hopf, Ph.D., Co-Director
Robert O. Messing, M.D., Co-Director
This project examines the contribution of atypical PKC (aPKC) isoforms in the NAcb on regulation of alcohol intake. A broad literature
supports a role for NAcb dopamine receptors and CB1 and mGluR5 receptors in sustaining alcohol intake in rodent. Our in vitro experiments
suggest that dopamine receptor enhancement of NAcb firing in vitro requires an atypical PKC isoform as well as CB1 and mGluR5 receptors.
Thus, we have developed shRNA constructs selective for inhibiting either the aPKC PKC zeta or the aPKC PKC iota/lambda. These are
packaged into AAV for infection of rat or mouse NAcb. We then determine the effect of these shRNAs on alcohol intake. We also examine
whether the same NAcb aPKC isoform that mediates alcohol intake also mediates the dopamine/cannabinoid enhancement of firing in vitro.
In addition, we utilize several transgenic mouse lines where inhibitory constructs for different aPKC isoforms are double-floxed. These mice can
then be bred with transgenic mouse CRE lines to allow cell type-selective knockdown. We can also inject a CRE-packaged virus locally within
the brain for knockdown in a particular region.
By identifying the NAcb signaling molecules through which dopamine receptors sustain alcohol intake, we hope to develop novel therapeutic
interventions to counter some of the biological effects of dopamine, but without the more negative side effects that existing dopamine receptor
antagonists often show in humans.
Ulrike Heberlein, Ph.D., Director
The goal of this component is to analyze the function of TAO (thousand-and-one amino acid) kinases and their
downstream signaling pathways in the regulation of ethanol-related behaviors. In a screen for ethanol-induced
hyperactivity mutants in Drosophila melanogaster, we recently identified a loss-of-function mutation in the
dtao gene that almost completely abolishes flies' hyperactivity response to ethanol. dtao encodes a putative
MAP3K of the GCK-VIII subfamily of Ste20p (sterile 20 protein) kinases. These proteins are characterized by
a highly conserved serine/threonine kinase domain, which regulates MAPK signaling cascades through ERK, JNK,
and/or p38. In addition to their catalytic function, TAO kinases have been shown to regulate cytoskeletal
organization through interaction with actin and tubulin, via a structurally divergent C-terminal tail
region. In mammals, dtao is represented by three orthologous genes: Taok1, Taok2 and Taok3, of which Taok1
and Taok2 are most highly expressed in the brain. To determine if the function of dTAO in regulating
ethanol-responsive behaviors is conserved in mammals, we are analyzing the behavioral response to ethanol
in mice in which the Taok1 and Taok2 genes have been conditionally disrupted. Our expectation is that these
data will: 1) identify new molecular pathways mediating the behavioral effects of ethanol, 2) provide new
mammalian models in which to study the effects of ethanol exposure, 3) identify potential genetic risk
factors for alcohol use disorders in humans, and 4) provide potential molecular targets for the development
of pharmacotherapies to treat alcoholism.
Dorit Ron, Ph.D., Director
The Pilot Project Program is intended to meet two major goals of the ACTG: (a) to enable the ACTG to explore new, innovative avenues of research and (b) to attract promising young or new investigators to the field of alcohol research. Pilot Projects provide seed funding to acquire the preliminary data necessary to apply for support through R01 or related mechanisms. Pilot Projects selected as part of the ACTG will be funded for one year and may be renewed for a total of two years. Projects may request a budget of up to $50,000 per year for direct costs. Pilot Project applications are solicited via a Call for Proposals emailed to all Gallo Center Principal Investigators and Associate Investigators, the UCSF Department of Neurology and the UCSF Neuroscience Graduate Program. The Call for Proposals is also posted on the ACTG website.
|
2008-2009 |
F. Woody Hopf |
Distinct atypical PKC isoforms in the nucleus accumbens and ethanol response |
|
2008-2010 |
Frederick Wolf |
Puckered and Decaptentaplegic signaling in ethanol behaviors in Drosophila |
|
2009-2010 |
Louis Ptacek |
Non-circadian behavioral assessment of mice carrying human clock mutations |
|
2009-2011 |
Jennifer Whistler |
Delta opioid receptor subtype-selective effects on ethanol seeking |
|
2010-2011 |
Kara Lynch |
Effect of polymorphisms in UGTs and SULTs on the excretion of alcohol biomarkers |
|
2010-2012 |
Elyssa Margolis |
VTA mechanisms involved in stress-induced ethanol consumption |
|
2011-2012 |
Eric Jorgenson |
Association study of alcohol use in diverse populations |
