Dorit Ron's Research
Harmful excessive use of alcohol has a severe impact on society and is one of the major causes of morbidity and mortality in the population. Unlike other drugs of abuse, alcohol does not have a well-defined site of action. Thus, mechanisms that underlie alcohol’s actions in the brain are poorly understood, and available medications for alcohol use disorders are limited. My lab is interested in elucidating molecular neuroadaptations that occur in the adult brain in response to alcohol exposure. Our long-term goal is to identify novel targets that could potentially be developed as therapeutics to treat alcohol abuse disorders including excessive alcohol intake, alcohol seeking and relapse. To do so, we combine molecular, genetic, electrophysiological and behavioral paradigms in rodents to address the following questions:
1. What are the mechanisms that prevent the majority of social drinkers from developing alcohol abuse disorders?
2. Are there molecular factors that increase the vulnerability and propensity to develop alcohol abuse disorders?
3. What are the signaling pathways that drive the transition from social drinking to excessive uncontrolled alcohol intake regardless of negative consequences, and how can the transition be prevented?
1. What are the mechanisms that prevent the majority of social drinkers from developing alcohol abuse disorders?
2. Are there molecular factors that increase the vulnerability and propensity to develop alcohol abuse disorders?
3. What are the signaling pathways that drive the transition from social drinking to excessive uncontrolled alcohol intake regardless of negative consequences, and how can the transition be prevented?
Representation of the signaling pathways underlying the light and dark sides of alcohol currently studied in the Dorit Ron's Lab.
The dark side of alcohol’s action (green light, left). Exposure to alcohol during recurring cycles of excessive alcohol intake and withdrawal and/or daily binge drinking of alcohol results in the activation of intracellular signaling cascades in specific brain regions. The activation of specific, usually linear, signaling pathways results in posttranslational modifications such as phosphorylation substrates and resultant changes in the activity of ion channels. Activation of signaling cascades, in many cases, leads to alterations in gene expression as well as the translation of mRNA to protein. For instance, upon activation of the H-Ras/AKT signaling cascade by alcohol, mammalian target of rapamycin complex 1 (mTORC1) is activated, leading to dendritic mRNA translation into synaptic proteins such as Homer, Arc, PSD-95 and the GluR1 subunit of the AMPAR. Alcohol also activates the Fyn/STEP/PTPalpha pathway in the dorsomedial striatum, which leads to a long-lasting phosphorylation of GluN2B, subsequently resulting in the forward trafficking of GluN2B to synaptic membranes and to a long-lasting facilitation of NMDAR activity. Epigenetic mechanisms also contribute to the dark side of alcohol’s actions. These signaling cascades drive long-lasting adverse behaviors associated with alcohol, behaviors such as excessive consumption, alcohol seeking, craving, and relapse. The light side of alcohol’s actions (red light, right). Moderate levels of alcohol consumption (social drinking) promotes the activation of signaling cascades that result in the expression of protective genes such as the growth factors brain-derived neurotrophic factor (BDNF) and glial cell line-derived neurotrophic factor (GDNF). In turn, the expression of BDNF and GDNF activates downstream pathways through their respective receptors TrkB and Ret/GFRalpha1, that prevent the “dark side” of alcohol from taking over. The proteins involved in maintaining the balance between the opposing “light” and “dark” forces represent potential drug targets for the treatment of alcohol-use disorders. Due to space limitations, not all proteins are presented in the model.
Adapted from Ahmadiantehrani S, Warnault V, Legastelois R and Ron D. From Signaling Pathways to Behavior, The Light and Dark Sides of Alcohol. Book chapter in Neurobiology of Alcohol Dependence, 2014, Pages 155-171.
The dark side of alcohol’s action (green light, left). Exposure to alcohol during recurring cycles of excessive alcohol intake and withdrawal and/or daily binge drinking of alcohol results in the activation of intracellular signaling cascades in specific brain regions. The activation of specific, usually linear, signaling pathways results in posttranslational modifications such as phosphorylation substrates and resultant changes in the activity of ion channels. Activation of signaling cascades, in many cases, leads to alterations in gene expression as well as the translation of mRNA to protein. For instance, upon activation of the H-Ras/AKT signaling cascade by alcohol, mammalian target of rapamycin complex 1 (mTORC1) is activated, leading to dendritic mRNA translation into synaptic proteins such as Homer, Arc, PSD-95 and the GluR1 subunit of the AMPAR. Alcohol also activates the Fyn/STEP/PTPalpha pathway in the dorsomedial striatum, which leads to a long-lasting phosphorylation of GluN2B, subsequently resulting in the forward trafficking of GluN2B to synaptic membranes and to a long-lasting facilitation of NMDAR activity. Epigenetic mechanisms also contribute to the dark side of alcohol’s actions. These signaling cascades drive long-lasting adverse behaviors associated with alcohol, behaviors such as excessive consumption, alcohol seeking, craving, and relapse. The light side of alcohol’s actions (red light, right). Moderate levels of alcohol consumption (social drinking) promotes the activation of signaling cascades that result in the expression of protective genes such as the growth factors brain-derived neurotrophic factor (BDNF) and glial cell line-derived neurotrophic factor (GDNF). In turn, the expression of BDNF and GDNF activates downstream pathways through their respective receptors TrkB and Ret/GFRalpha1, that prevent the “dark side” of alcohol from taking over. The proteins involved in maintaining the balance between the opposing “light” and “dark” forces represent potential drug targets for the treatment of alcohol-use disorders. Due to space limitations, not all proteins are presented in the model.
Adapted from Ahmadiantehrani S, Warnault V, Legastelois R and Ron D. From Signaling Pathways to Behavior, The Light and Dark Sides of Alcohol. Book chapter in Neurobiology of Alcohol Dependence, 2014, Pages 155-171.
Ron D. and Barak S. Molecular mechanisms underlying alcohol-drinking behaviors. Nature Reviews Neuroscience. 17, 576–591, 2016.
Beckley JT and Ron D. Molecules to Medicine with mTOR. Elsevier Academic Press. 2016. 215-226.
Logrip ML, Barak S, Warnault V, Ron D. Corticostriatal BDNF and alcohol addiction. Brain Res. 2015 Mar 21. pii: S0006-8993(15)00221-8.
Neasta J, Barak S, Ben Hamida S, Ron D. mTOR Complex 1: A Key Player in Neuroadaptations Induced by Drugs of Abuse. J Neurochem. 2014 Jul;130(2):172-84.
Warnault V, Ron D. Chromatin remodeling: a new landscape to treat harmful alcohol-use disorders. Future Med Chem. 2013; 5:2011-3.
Ron D, Adams DR, Baillie GS, Long A, O'Connor R, Kiely PA. RACK(1) to the future - a historical perspective. Cell Commun Signal. 2013; 11:53.
Ron D. and Messing RO. Signaling pathways mediating alcohol effects. Curr Top Behav Neurosci. 2013; 13:87-126.
Adams DR, Ron D, Kiely PA. RACK1, A Multifaceted Scaffolding Protein: Structure and Function. Cell Commun Signal. 2011; 9:22.
Carnicella S and Ron D. GDNF--a potential target to treat addiction. Pharmacol Ther. 2009; 22:9-18.
Ron, D. and Janak, P.H. GDNF and Addiction. 2frevneuro.2005.16.4href="dg/viewarticle/j-002frevneuro.2005.16.4-002frevneuro.2005.16.4.277-002frevneuro.2005.16.4.277.xm">2frevneuro.2005.16.4.277href="dg/viewarticle/j-002frevneuro.2005.16.4-002frevneuro.2005.16.4.277-002frevneuro.2005.16.4.277.xm">2frevneuro.2005.16.4.277.xml;jsessionid=26D3A63C6F302F791CC10FDF1AD6E9E3">Reviews in the Neurosciences. 2005; 16:277-285.
Ron, D. and Jurd, R. The "ups and downs" of signaling cascades in addiction. Science STKE. 2005; 309:14,5.
Ron, D., Signaling Cascades Regulating NMDA Receptor Sensitivity to Ethanol. Neuroscientist. 2004; 10:325-336.
Beckley JT and Ron D. Molecules to Medicine with mTOR. Elsevier Academic Press. 2016. 215-226.
Logrip ML, Barak S, Warnault V, Ron D. Corticostriatal BDNF and alcohol addiction. Brain Res. 2015 Mar 21. pii: S0006-8993(15)00221-8.
Neasta J, Barak S, Ben Hamida S, Ron D. mTOR Complex 1: A Key Player in Neuroadaptations Induced by Drugs of Abuse. J Neurochem. 2014 Jul;130(2):172-84.
Warnault V, Ron D. Chromatin remodeling: a new landscape to treat harmful alcohol-use disorders. Future Med Chem. 2013; 5:2011-3.
Ron D, Adams DR, Baillie GS, Long A, O'Connor R, Kiely PA. RACK(1) to the future - a historical perspective. Cell Commun Signal. 2013; 11:53.
Ron D. and Messing RO. Signaling pathways mediating alcohol effects. Curr Top Behav Neurosci. 2013; 13:87-126.
Adams DR, Ron D, Kiely PA. RACK1, A Multifaceted Scaffolding Protein: Structure and Function. Cell Commun Signal. 2011; 9:22.
Carnicella S and Ron D. GDNF--a potential target to treat addiction. Pharmacol Ther. 2009; 22:9-18.
Ron, D. and Janak, P.H. GDNF and Addiction. 2frevneuro.2005.16.4href="dg/viewarticle/j-002frevneuro.2005.16.4-002frevneuro.2005.16.4.277-002frevneuro.2005.16.4.277.xm">2frevneuro.2005.16.4.277href="dg/viewarticle/j-002frevneuro.2005.16.4-002frevneuro.2005.16.4.277-002frevneuro.2005.16.4.277.xm">2frevneuro.2005.16.4.277.xml;jsessionid=26D3A63C6F302F791CC10FDF1AD6E9E3">Reviews in the Neurosciences. 2005; 16:277-285.
Ron, D. and Jurd, R. The "ups and downs" of signaling cascades in addiction. Science STKE. 2005; 309:14,5.
Ron, D., Signaling Cascades Regulating NMDA Receptor Sensitivity to Ethanol. Neuroscientist. 2004; 10:325-336.
Current Projects
1. Identifying the function of the growth factors BDNF and GDNF in alcohol abuse disorders.
2. Determining the role of mTOR in aberrant synaptic plasticity induced by drugs of abuse.
3. Identifying the role of kinases and phosphatases and anchoring proteins in normal CNS functions and in neuroadaptations underlying addiction.
4. Epigenetic mechanisms and addiction.
5. Identifying the role of HSP90 in alcohol abuse disorders.
Tools
The Ron lab is using a wide range of molecular, biochemical, electrophysiological and behavioral techniques to uncover the molecular mechanisms that underlies alcohol use and abuse disorders.
Molecular Biology and BiochemistryWe are using both classical (Western- blot, ELISA, RT-PCR, qPCR, immunoprecipitation (IP), co-IP, immunohistochemistry) and state of the art and newly developed molecular tools (RNA-seq, microRNA-qPCR, chromatin-IP (ChIP) and CLARITY) to assess the levels of mRNA, microRNA, epigenetic changes and proteins levels, localization and interactions in specific brain regions or in specific subpopulations of neurons. We use virus-mediated gene delivery to knockdown genes using the siRNA approach in addition to overexpress genes in specific brain regions. We use fractionation techniques to isolate cellular compartments such as the nucleus, lipid rafts and synaptic fraction. We recently developed polysomal fractionation, a procedure that allows us to specifically study transcripts bound to the ribosomes (i.e. mRNA under transcription). |
ElectrophysiologyWe use whole cell patch clamp electrophysiology in acute brain slices to investigate how alcohol alters synaptic transmission and intrinsic neuronal excitability. In some experiments, we record neurons from slices in vitro, and examine how alcohol acutely alters channel function. More commonly, we use mice that have received alcohol and record from neurons ex vivo, to determine how an alcohol challenge alters synaptic physiology. Because our goal is to understand how alcohol alters specific circuits, such as the mesolimbic pathway, we use patch-clamp electrophysiology combined with other tools to enhance our selectivity. For example, we use mice that either have a reporter gene in D1R or D2R neurons, so we can record selectively from striatal direct pathway or indirect pathway neurons, respectively. We also use optogenetics or pharmacogenetics (i.e. DREADD receptors) to selectively activate or inhibit presynaptic terminals. Combining patch-clamp electrophysiology with transgenic animals and viral vectors allows us to examine how alcohol affects neuronal physiology in specific circuits and neuronal sub-populations. Acute and chronic alcohol use can dramatically alter brain morphology at all levels of organization, including dendritic spines. We are interested in studying how alcohol affects both the physiological and anatomical components at the level of a single neuron. We are determining whether alcohol alters dendritic length and complexity, as well as dendritic spine characteristics, by analyzing deconvolved 3-D confocal images of single neurons. |
BehaviorWe are using rodents (mice and rats) and numerous transgenic mice lines, to study the involvement of specific pathways in alcohol use disorders. In order to modify the expression of genes in one specific brain region, we use viral-mediated gene delivery to knockdown or overexpress specific genes. We even recently developed a method to knockdown or overexpress a gene specifically in one subpopulation of neurons in a discrete brain region. We use different paradigms of voluntary alcohol drinking mimicking moderate (two-bottle choice continuous alcohol access) or excessive and binge drinking of alcohol (two-bottle choice intermittent access to alcohol, limited access drinking in the dark). We also use alcohol self-administration paradigms in both mice and rats, which allow studying the motivation of rodents to drink alcohol, as well as the extinction and relapse of the response towards alcohol. We use these paradigms to test, for example, the efficacy of new pharmacological drugs on alcohol intake. To assess the hedonic or aversive properties of alcohol or other drugs, we use the classical conditioned place preference or aversion procedures. We are also working with other behavioral paradigms that assess alcohol-related behaviors such as alcohol-induced behavioral sensitization, anxiety-like behaviors (elevated-plus maze), ataxia (rotarod), sedation (loss of righting reflex) and compulsivity (Y maze). |