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Pizzoni A, Zhang X, Altschuler DL. From membrane to nucleus: A three-wave hypothesis of cAMP signaling. J Biol Chem 2024; 300:105497. [PMID: 38016514 PMCID: PMC10788541 DOI: 10.1016/j.jbc.2023.105497] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2023] [Revised: 11/14/2023] [Accepted: 11/19/2023] [Indexed: 11/30/2023] Open
Abstract
For many decades, our understanding of G protein-coupled receptor (GPCR) activity and cyclic AMP (cAMP) signaling was limited exclusively to the plasma membrane. However, a growing body of evidence has challenged this view by introducing the concept of endocytosis-dependent GPCR signaling. This emerging paradigm emphasizes not only the sustained production of cAMP but also its precise subcellular localization, thus transforming our understanding of the spatiotemporal organization of this process. Starting from this alternative point of view, our recent work sheds light on the role of an endocytosis-dependent calcium release from the endoplasmic reticulum in the control of nuclear cAMP levels. This is achieved through the activation of local soluble adenylyl cyclase, which in turn regulates the activation of local protein kinase A (PKA) and downstream transcriptional events. In this review, we explore the dynamic evolution of research on cyclic AMP signaling, including the findings that led us to formulate the novel three-wave hypothesis. We delve into how we abandoned the paradigm of cAMP generation limited to the plasma membrane and the changing perspectives on the rate-limiting step in nuclear PKA activation.
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Affiliation(s)
- Alejandro Pizzoni
- Department of Pharmacology and Chemical Biology, School of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Xuefeng Zhang
- Department of Pharmacology and Chemical Biology, School of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Daniel L Altschuler
- Department of Pharmacology and Chemical Biology, School of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, USA.
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2
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Alcohol. Alcohol 2021. [DOI: 10.1016/b978-0-12-816793-9.00001-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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3
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Manca S, Frisbie CP, LaGrange CA, Casey CA, Riethoven JJM, Petrosyan A. The Role of Alcohol-Induced Golgi Fragmentation for Androgen Receptor Signaling in Prostate Cancer. Mol Cancer Res 2018; 17:225-237. [PMID: 30224543 DOI: 10.1158/1541-7786.mcr-18-0577] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2018] [Revised: 07/23/2018] [Accepted: 08/22/2018] [Indexed: 01/18/2023]
Abstract
Multiple epidemiologic observations and meta-analysis clearly indicate the link between alcohol abuse and the incidence and progression of prostate cancer; however, the mechanism remains enigmatic. Recently, it was found that ethanol (EtOH) induces disorganization of the Golgi complex caused by impaired function of the largest Golgi matrix protein, giantin (GOLGB1), which, in turn, alters the Golgi docking of resident Golgi proteins. Here, it is determined that in normal prostate cells, histone deacetylase 6 (HDAC6), the known regulator of androgen receptor (AR) signaling, localizes in the cytoplasm and nucleus, while its kinase, glycogen synthase kinase β (GSK3β), primarily resides in the Golgi. Progression of prostate cancer is accompanied by Golgi scattering, translocation of GSK3β from the Golgi to the cytoplasm, and the cytoplasmic shift in HDAC6 localization. Alcohol dehydrogenase-generated metabolites induces Golgi disorganization in androgen-responsive LNCaP and 22Rv1 cells, facilitates tumor growth in a mouse xenograft model and activates anchorage-independent proliferation, migration, and cell adhesion. EtOH-treated cells demonstrate reduced giantin and subsequent cytoplasmic GSK3β; this phenomenon was validated in giantin-depleted cells. Redistribution of GSK3β to the cytoplasm results in phosphorylation of HDAC6 and its retention in the cytoplasm, which, in turn, stimulates deacetylation of HSP90, AR import into the nucleus, and secretion of prostate-specific antigen (PSA). Finally, the relationship between Golgi morphology, HDAC6 cytoplasmic content, and clinicopathologic features was assessed in human prostate cancer patient specimens with and without a history of alcohol dependence. IMPLICATIONS: This study demonstrates the importance of alcohol-induced Golgi fragmentation in the activation of AR-mediated proliferation.
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Affiliation(s)
- Sonia Manca
- Department of Biochemistry and Molecular Biology, College of Medicine, University of Nebraska Medical Center, Omaha, Nebraska
| | - Cole P Frisbie
- Department of Biochemistry and Molecular Biology, College of Medicine, University of Nebraska Medical Center, Omaha, Nebraska
| | - Chad A LaGrange
- Division of Urologic Surgery, Department of Surgery, University of Nebraska Medical Center, Omaha, Nebraska
| | - Carol A Casey
- Department of Internal Medicine, University of Nebraska Medical Center, Omaha, Nebraska
| | - Jean-Jack M Riethoven
- Center for Biotechnology, University of Nebraska-Lincoln, Lincoln, Nebraska.,The Nebraska Center for Integrated Biomolecular Communication, Lincoln, Nebraska
| | - Armen Petrosyan
- Department of Biochemistry and Molecular Biology, College of Medicine, University of Nebraska Medical Center, Omaha, Nebraska. .,The Nebraska Center for Integrated Biomolecular Communication, Lincoln, Nebraska.,The Fred and Pamela Buffett Cancer Center, Omaha, Nebraska
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Gu Y, Xu W, Zhuang B, Fu W. Role of A-kinase anchoring protein 95 in the regulation of cytochrome P450 family 19 subfamily A member 1 (CYP19A1) in human ovarian granulosa cells. Reprod Fertil Dev 2018; 30:1128-1136. [DOI: 10.1071/rd17313] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2017] [Accepted: 01/02/2018] [Indexed: 11/23/2022] Open
Abstract
Irregular expression of cytochrome P450 family 19 subfamily A member 1 (CYP19A1) is involved in the development of polycystic ovary syndrome (PCOS). Activation of the cAMP/protein kinase A (PKA)/cAMP response element-binding protein (CREB) pathway plays a crucial role in FSH regulation of CYP19A1 in human ovarian granulosa cells. A-Kinase anchor protein 95 (AKAP95) is known to confine PKA to the nucleus. However, it is unclear whether anchoring PKA to the nucleus is essential for the induction of CYP19A1 by FSH in human ovarian granulosa cells. Using the human granulosa cell line KGN and primary cultured human luteinised granulosa cells (hLGCs), we found that knockdown of AKAP8, the gene encoding AKAP95, or inhibition of AKAP95 reduced the amount of PKA anchored in the nucleus and attenuated the phosphorylation of CREB by either FSH or activation of the cAMP/PKA pathway. Moreover, knockdown of AKAP8 or inhibition of AKAP95 also significantly attenuated FSH-induced CYP19A1 expression and oestrogen synthesis. Furthermore, significant decreases in AKAP95 and CYP19A1 were observed in hLGCs obtained from PCOS patients. The results of the present study demonstrate a crucial role for AKAP95 in CYP19A1 expression and oestrogen synthesis in hLGCs, which implies that AKAP95 may be involved in the pathogenesis of PCOS.
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Hill RA, Xu W, Yoshimura M. Role of an adenylyl cyclase isoform in ethanol's effect on cAMP regulated gene expression in NIH 3T3 cells. Biochem Biophys Rep 2017; 8:162-167. [PMID: 28620651 PMCID: PMC5467537 DOI: 10.1016/j.bbrep.2016.08.025] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Previous research has indicated that the cyclic AMP (cAMP) signal transduction system plays an important role in the predisposition to and development of ethanol abuse in humans. Our laboratory has demonstrated that ethanol is capable of enhancing adenylyl cyclase (AC) activity. This effect is AC isoform-specific; type 7 AC (AC7) is most enhanced by ethanol. Therefore, we hypothesized that the expression of a specific AC isoform will play a role on the effect of ethanol on cAMP regulated gene expression. We employed NIH 3T3 cells transfected with AC7 or AC3 as a model system. To evaluate ethanol's effects on cAMP regulated gene expression, a luciferase reporter gene driven by a cAMP inducing artificial promoter was utilized. Stimulation of AC activity leads to an increase in the reporter gene activity. This increase was enhanced in the presence of ethanol in cells expressing AC7, while cells expressing AC3 did not respond to ethanol. cAMP reporter gene expression was increased in the presence of 8-bromo-cAMP; this expression was not enhanced by ethanol. These observations are consistent with our hypothesis. The basal level of CREB phosphorylation was high and did not change by cAMP stimulation or in the presence of ethanol. However, there were significant changes in the TORC3 amount in nuclei depending on stimulation conditions. The results suggest that nuclear translocation of TORC3 plays a more important role than CREB phosphorylation in the observed changes in the cAMP driven reporter gene activity. Effect of ethanol on cAMP regulated gene expression is AC isoform dependent. cAMP regulated gene expression is most enhanced by ethanol in cells expressing AC7. Gene expression increases with pharmacologically relevant ethanol concentrations. TORC3 nuclear translocation is important for cAMP reporter gene activity.
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Affiliation(s)
- Rebecca A Hill
- Department of Comparative Biomedical Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, LA, USA
| | - Wu Xu
- Department of Comparative Biomedical Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, LA, USA
| | - Masami Yoshimura
- Department of Comparative Biomedical Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, LA, USA
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Goodlett CR, Horn KH, Zhou FC. Alcohol Teratogenesis: Mechanisms of Damage and Strategies for Intervention. Exp Biol Med (Maywood) 2016; 230:394-406. [PMID: 15956769 DOI: 10.1177/15353702-0323006-07] [Citation(s) in RCA: 281] [Impact Index Per Article: 35.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
There are multiple mechanisms by which alcohol can damage the developing brain, but the type of damage induced will depend on the amount and developmental timing of exposure, along with other maternal and genetic factors. This article reviews current perspectives on how ethanol can produce neuroteratogenic effects by its interactions with molecular regulators of brain development. The current evidence suggests that alcohol produces many of its damaging effects by exerting specific actions on molecules that regulate key developmental processes (e.g., L1 cell adhesion molecule, alcohol dehydrogenase, catalase), interfering with the early development of midline serotonergic neurons and disrupting their regulatory-signaling function for other target brain structures, interfering with trophic factors that regulate neurogenesis and cell survival, or inducing excessive cell death via oxidative stress or activation of caspase-3 proteases. The current understanding of pathogenesis mechanisms suggests several strategic approaches to develop rational molecular prevention. However, the development of behavioral and biologic treatments for alcohol-affected children is crucial because it is unlikely that effective delivery of preventative interventions can realistically be achieved in ways to prevent prenatal damage in at-risk pregnancies. Toward that end, behavioral training that promotes experience-dependent neuroplasticity has been effective in a rat model of cerebellar damage induced by alcohol exposure during the period of brain development that is comparable to that of the human third trimester.
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Affiliation(s)
- Charles R Goodlett
- Department of Psychology, Indiana University-Purdue University at Indianapolis, 402 North Blackford Street, Indianapolis, Indiana 46202, USA.
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Mons N, Beracochea D. Behavioral Neuroadaptation to Alcohol: From Glucocorticoids to Histone Acetylation. Front Psychiatry 2016; 7:165. [PMID: 27766083 PMCID: PMC5052254 DOI: 10.3389/fpsyt.2016.00165] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/30/2016] [Accepted: 09/21/2016] [Indexed: 01/21/2023] Open
Abstract
A prime mechanism that contributes to the development and maintenance of alcoholism is the dysregulation of the hypothalamic-pituitary-adrenal axis activity and the release of glucocorticoids (cortisol in humans and primates, corticosterone in rodents) from the adrenal glands. In the brain, sustained, local elevation of glucocorticoid concentration even long after cessation of chronic alcohol consumption compromises functional integrity of a circuit, including the prefrontal cortex (PFC), the hippocampus (HPC), and the amygdala (AMG). These structures are implicated in learning and memory processes as well as in orchestrating neuroadaptive responses to stress and anxiety responses. Thus, potentiation of anxiety-related neuroadaptation by alcohol is characterized by an abnormally AMG hyperactivity coupled with a hypofunction of the PFC and the HPC. This review describes research on molecular and epigenetic mechanisms by which alcohol causes distinct region-specific adaptive changes in gene expression patterns and ultimately leads to a variety of cognitive and behavioral impairments on prefrontal- and hippocampal-based tasks. Alcohol-induced neuroadaptations involve the dysregulation of numerous signaling cascades, leading to long-term changes in transcriptional profiles of genes, through the actions of transcription factors such as [cAMP response element-binding protein (CREB)] and chromatin remodeling due to posttranslational modifications of histone proteins. We describe the role of prefrontal-HPC-AMG circuit in mediating the effects of acute and chronic alcohol on learning and memory, and region-specific molecular and epigenetic mechanisms involved in this process. This review first discusses the importance of brain region-specific dysregulation of glucocorticoid concentration in the development of alcohol dependence and describes how persistently increased glucocorticoid levels in PFC may be involved in mediating working memory impairments and neuroadaptive changes during withdrawal from chronic alcohol intake. It then highlights the role of cAMP-PKA-CREB signaling cascade and histone acetylation within the PFC and limbic structures in alcohol-induced anxiety and behavioral impairments, and how an understanding of functional alterations of these pathways might lead to better treatments for neuropsychiatric disorders.
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Affiliation(s)
- Nicole Mons
- CNRS UMR 5287, Institut des Neurosciences cognitives et intégratives d'Aquitaine, Nouvelle Université de Bordeaux , Pessac , France
| | - Daniel Beracochea
- CNRS UMR 5287, Institut des Neurosciences cognitives et intégratives d'Aquitaine, Nouvelle Université de Bordeaux , Pessac , France
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Logrip ML. Phosphodiesterase regulation of alcohol drinking in rodents. Alcohol 2015; 49:795-802. [PMID: 26095589 DOI: 10.1016/j.alcohol.2015.03.007] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2015] [Revised: 03/13/2015] [Accepted: 03/14/2015] [Indexed: 12/22/2022]
Abstract
Alcohol use disorders are chronically relapsing conditions characterized by persistent drinking despite the negative impact on one's life. The difficulty of achieving and maintaining sobriety suggests that current treatments fail to fully address the underlying causes of alcohol use disorders. Identifying additional pathways controlling alcohol consumption may uncover novel targets for medication development to improve treatment options. One family of proteins recently implicated in the regulation of alcohol consumption is the cyclic nucleotide phosphodiesterases (PDEs). As an integral component in the regulation of the second messengers cyclic AMP and cyclic GMP, and thus their cognate signaling pathways, PDEs present intriguing targets for pharmacotherapies to combat alcohol use disorders. As activation of cAMP/cGMP-dependent signaling cascades can dampen alcohol intake, PDE inhibitors may provide a novel target for reducing excessive alcohol consumption, as has been proposed for PDE4 and PDE10A. This review highlights preclinical literature demonstrating the involvement of cyclic nucleotide-dependent signaling in neuronal and behavioral responses to alcohol, as well as detailing the capacity of various PDE inhibitors to modulate alcohol intake. Together these data provide a framework for evaluating the potential utility of PDE inhibitors as novel treatments for alcohol use disorders.
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Lakhter AJ, Lahm T, Broxmeyer HE, Naidu SR. Golgi Associated HIF1a Serves as a Reserve in Melanoma Cells. J Cell Biochem 2015; 117:853-9. [PMID: 26375488 DOI: 10.1002/jcb.25381] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2015] [Accepted: 09/14/2015] [Indexed: 11/09/2022]
Abstract
Hypoxia-inducible factor-1alpha (HIF1a) is a key transcriptional regulator that enables cellular metabolic adaptation to low levels of oxygen. Multiple mechanisms, including lysosomal degradation, control the levels of HIF1a protein. Here we show that HIF1a protein degradation is resistant to lysosomal inhibition and that HIF1a is associated with the Golgi compartment in melanoma cells. Although pharmacological inhibitors of prolyl hydroxylation, neddylation and the proteasome inhibited degradation of HIF1a, attenuation of lysosomal activity with chloroquine did not alter the levels of HIF1a or its association with Golgi. Pharmacological disruption of Golgi resulted in nuclear accumulation of HIF1a. However, blockade of ER-Golgi protein transport in hypoxia reduced the transcript levels of HIF1a target genes. These findings suggest a possible role for the oxygen-dependent protein folding process from the ER-Golgi compartment in fine-tuning HIF1a transcriptional output.
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Affiliation(s)
- Alexander J Lakhter
- Department of Dermatology, Indiana University School of Medicine, Indianapolis, Indiana, 46202
| | - Tim Lahm
- Department of Medicine, Indiana University School of Medicine, Indianapolis, Indiana, 46202
| | - Hal E Broxmeyer
- Department of Microbiology/Immunology, Indiana University School of Medicine, Indianapolis, Indiana, 46202
| | - Samisubbu R Naidu
- Department of Dermatology, Indiana University School of Medicine, Indianapolis, Indiana, 46202
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Giralt A, Saavedra A, Carretón O, Arumí H, Tyebji S, Alberch J, Pérez-Navarro E. PDE10 inhibition increases GluA1 and CREB phosphorylation and improves spatial and recognition memories in a Huntington's disease mouse model. Hippocampus 2013; 23:684-95. [PMID: 23576401 DOI: 10.1002/hipo.22128] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/22/2013] [Indexed: 12/20/2022]
Abstract
Huntington's disease (HD) causes motor disturbances, preceded by cognitive impairment, in patients and mouse models. We showed that increased hippocampal cAMP-dependent protein kinase (PKA) signaling disrupts recognition and spatial memories in R6 HD mouse models. However, unchanged levels of hippocampal phosphorylated (p) cAMP-responsive element-binding protein (CREB) suggested unaltered nuclear PKA activity in R6 mice. Here, we extend this finding by showing that nuclear pPKA catalytic subunit (Thr197) and pPKA substrate levels were unaltered in the hippocampus of R6/1 mice. Phosphodiesterases (PDEs) play an important role in the regulation of PKA activity. PDE10A, a cAMP/cGMP dual-substrate PDE, was reported to be restricted to the nuclear region in nonstriatal neurons. Using cell fractionation we confirmed that PDE10A was enriched in nuclear fractions, both in wild-type and R6/1 mice hippocampus, without differences in its levels or intracellular distribution between genotypes. We next investigated whether inhibition of PDE10 with papaverine could improve cognitive function in HD mice. Papaverine treatment improved spatial and object recognition memories in R6/1 mice, and significantly increased pGluA1 and pCREB levels in R6/1 mice hippocampus. Papaverine likely acted through the activation of the PKA pathway as the phosphorylation level of distinct cGMP-dependent kinase (cGK) substrates was not modified in either genotype. Moreover, hippocampal cAMP, but not cGMP, levels were increased after acute papaverine injection. Our results show that inhibition of PDE10 improves cognition in R6 mice, at least in part through increased GluA1 and CREB phosphorylation. Thus, PDE10 might be a good therapeutic target to improve cognitive impairment in HD.
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Affiliation(s)
- Albert Giralt
- Departament de Biologia Cellular, Immunologia i Neurociències, Facultat de Medicina, Universitat de Barcelona, Barcelona, Spain
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McBride WJ, Kimpel MW, McClintick JN, Ding ZM, Hyytia P, Colombo G, Edenberg HJ, Lumeng L, Bell RL. Gene expression in the ventral tegmental area of 5 pairs of rat lines selectively bred for high or low ethanol consumption. Pharmacol Biochem Behav 2012; 102:275-85. [PMID: 22579914 PMCID: PMC3383357 DOI: 10.1016/j.pbb.2012.04.016] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/17/2011] [Revised: 04/20/2012] [Accepted: 04/30/2012] [Indexed: 12/28/2022]
Abstract
The objective of this study was to determine if there are common innate differences in gene expression or gene pathways in the ventral tegmental area (VTA) among 5 different pairs of rat lines selectively bred for high (HEC) or low (LEC) ethanol consumption: (a) alcohol-preferring (P) vs. alcohol-non-preferring (NP) rats; (b) high-alcohol-drinking (HAD) vs. low-alcohol-drinking (LAD) rats (replicate line pairs 1 and 2); (c) ALKO alcohol (AA) vs. nonalcohol (ANA) rats; and (d) Sardinian alcohol-preferring (sP) vs. alcohol-nonpreferring (sNP) rats. Microarray analysis revealed between 370 and 1340 unique named genes that significantly differed in expression between the individual line-pairs. Analysis using Gene Ontology (GO) and Ingenuity Pathways information indicated significant categories and networks in common for up to 3 line-pairs, but not for all 5 line-pairs; moreover, there were few genes in common in these categories and networks. ANOVA of the combined data for the 5 line-pairs indicated 1295 significant (p<0.01) differences in expression of named genes. Although no individual named gene was significant across all 5 line-pairs, there were 22 genes that overlapped in the same direction in 3 or 4 of the line-pairs. Overall, the findings suggest that (a) some biological categories or networks may be in common for subsets of line-pairs; and (b) regulation of different genes and/or combinations of multiple biological systems (e.g., transcription, synaptic function, intracellular signaling and protection against oxidative stress) within the VTA (possibly involving dopamine and glutamate) may be contributing to the disparate alcohol drinking behaviors of these line-pairs.
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Affiliation(s)
- William J McBride
- Institute of Psychiatric Research, Department of Psychiatry, Indiana University School of Medicine, Indianapolis, IN 46202-4887, USA.
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Bahi A, Dreyer JL. Involvement of tissue plasminogen activator “tPA” in ethanol-induced locomotor sensitization and conditioned-place preference. Behav Brain Res 2012; 226:250-8. [DOI: 10.1016/j.bbr.2011.09.024] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2011] [Revised: 08/25/2011] [Accepted: 09/12/2011] [Indexed: 12/26/2022]
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Moonat S, Starkman BG, Sakharkar A, Pandey SC. Neuroscience of alcoholism: molecular and cellular mechanisms. Cell Mol Life Sci 2010; 67:73-88. [PMID: 19756388 PMCID: PMC3747955 DOI: 10.1007/s00018-009-0135-y] [Citation(s) in RCA: 100] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2009] [Revised: 07/28/2009] [Accepted: 08/13/2009] [Indexed: 01/21/2023]
Abstract
Alcohol use and abuse appear to be related to neuroadaptive changes at functional, neurochemical, and structural levels. Acute and chronic ethanol exposure have been shown to modulate function of the activity-dependent gene transcription factor, cAMP-responsive element binding (CREB) protein in the brain, which may be associated with the development of alcoholism. Study of the downstream effectors of CREB have identified several important CREB-related genes, such as neuropeptide Y, brain-derived neurotrophic factor, activity-regulated cytoskeleton-associated protein, and corticotrophin-releasing factor, that may play a crucial role in the behavioral effects of ethanol and molecular changes in the specific neurocircuitry that underlie both alcohol addiction and a genetic predisposition to alcoholism. Brain chromatin remodeling due to histone covalent modifications may also be involved in mediating the behavioral effects and neuroadaptive changes that occur during ethanol exposure. This review outlines progressive neuroscience research into molecular and epigenetic mechanisms of alcoholism.
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Affiliation(s)
- Sachin Moonat
- Department of Psychiatry, University of Illinois at Chicago, Chicago, IL USA
- Jesse Brown VA Medical Center, Chicago, IL USA
| | - Bela G. Starkman
- Department of Psychiatry, University of Illinois at Chicago, Chicago, IL USA
- Department of Anatomy and Cell Biology, University of Illinois at Chicago, Chicago, IL USA
- Jesse Brown VA Medical Center, Chicago, IL USA
| | - Amul Sakharkar
- Department of Psychiatry, University of Illinois at Chicago, Chicago, IL USA
- Jesse Brown VA Medical Center, Chicago, IL USA
| | - Subhash C. Pandey
- Department of Psychiatry, University of Illinois at Chicago, Chicago, IL USA
- Department of Anatomy and Cell Biology, University of Illinois at Chicago, Chicago, IL USA
- Jesse Brown VA Medical Center, Chicago, IL USA
- Department of Psychiatry, University of Illinois at Chicago and Jesse Brown VA Medical Center, 820 S. Damen Avenue (M/C 151), Chicago, IL 60612 USA
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Krahe TE, Wang W, Medina AE. Phosphodiesterase inhibition increases CREB phosphorylation and restores orientation selectivity in a model of fetal alcohol spectrum disorders. PLoS One 2009; 4:e6643. [PMID: 19680548 PMCID: PMC2721629 DOI: 10.1371/journal.pone.0006643] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2009] [Accepted: 07/14/2009] [Indexed: 12/15/2022] Open
Abstract
Background Fetal alcohol spectrum disorders (FASD) are the leading cause of mental retardation in the western world and children with FASD present altered somatosensory, auditory and visual processing. There is growing evidence that some of these sensory processing problems may be related to altered cortical maps caused by impaired developmental neuronal plasticity. Methodology/Principal Findings Here we show that the primary visual cortex of ferrets exposed to alcohol during the third trimester equivalent of human gestation have decreased CREB phosphorylation and poor orientation selectivity revealed by western blotting, optical imaging of intrinsic signals and single-unit extracellular recording techniques. Treating animals several days after the period of alcohol exposure with a phosphodiesterase type 1 inhibitor (Vinpocetine) increased CREB phosphorylation and restored orientation selectivity columns and neuronal orientation tuning. Conclusions/Significance These findings suggest that CREB function is important for the maturation of orientation selectivity and that plasticity enhancement by vinpocetine may play a role in the treatment of sensory problems in FASD.
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Affiliation(s)
- Thomas E. Krahe
- Department of Anatomy and Neurobiology, Virginia Commonwealth University Medical Center, Richmond, Virginia, United States of America
| | - Weili Wang
- Department of Anatomy and Neurobiology, Virginia Commonwealth University Medical Center, Richmond, Virginia, United States of America
| | - Alexandre E. Medina
- Department of Anatomy and Neurobiology, Virginia Commonwealth University Medical Center, Richmond, Virginia, United States of America
- * E-mail:
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Conti AC, Maas JW, Moulder KL, Jiang X, Dave BA, Mennerick S, Muglia LJ. Adenylyl cyclases 1 and 8 initiate a presynaptic homeostatic response to ethanol treatment. PLoS One 2009; 4:e5697. [PMID: 19479030 PMCID: PMC2682654 DOI: 10.1371/journal.pone.0005697] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2008] [Accepted: 04/16/2009] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND Although ethanol exerts widespread action in the brain, only recently has progress been made in understanding the specific events occurring at the synapse during ethanol exposure. Mice deficient in the calcium-stimulated adenylyl cyclases, AC1 and AC8 (DKO), demonstrate increased sedation duration and impaired phosphorylation by protein kinase A (PKA) following acute ethanol treatment. While not direct targets for ethanol, we hypothesize that these cyclases initiate a homeostatic presynaptic response by PKA to reactivate neurons from ethanol-mediated inhibition. METHODOLOGY/PRINCIPAL FINDINGS Here, we have used phosphoproteomic techniques and identified several presynaptic proteins that are phosphorylated in the brains of wild type mice (WT) after ethanol exposure, including synapsin, a known PKA target. Phosphorylation of synapsins I and II, as well as phosphorylation of non-PKA targets, such as, eukaryotic elongation factor-2 (eEF-2) and dynamin is significantly impaired in the brains of DKO mice. This deficit is primarily driven by AC1, as AC1-deficient, but not AC8-deficient mice also demonstrate significant reductions in phosphorylation of synapsin and eEF-2 in cortical and hippocampal tissues. DKO mice have a reduced pool of functional recycling vesicles and fewer active terminals as measured by FM1-43 uptake compared to WT controls, which may be a contributing factor to the impaired presynaptic response to ethanol treatment. CONCLUSIONS/SIGNIFICANCE These data demonstrate that calcium-stimulated AC-dependent PKA activation in the presynaptic terminal, primarily driven by AC1, is a critical event in the reactivation of neurons following ethanol-induced activity blockade.
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Affiliation(s)
- Alana C Conti
- Department of Pediatrics, Washington University in St. Louis, St. Louis, Missouri, United States of America.
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Yang W, Harris MA, Heinrich JG, Guo D, Bonewald LF, Harris SE. Gene expression signatures of a fibroblastoid preosteoblast and cuboidal osteoblast cell model compared to the MLO-Y4 osteocyte cell model. Bone 2009; 44:32-45. [PMID: 18973839 PMCID: PMC2692918 DOI: 10.1016/j.bone.2008.08.133] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/19/2007] [Revised: 08/01/2008] [Accepted: 08/19/2008] [Indexed: 01/08/2023]
Abstract
In the osteoblast 2T3 cell model, 326 genes significantly increase in expression as subconfluent fibroblastic 2T3 cells become confluent and cuboidal. This gene set includes BMP2/4, Dlx2/5, Runx2, Osterix and Lrp5, as well as TGFbeta regulated genes. Both activated or total nuclear Smad158 and Smad2 levels increase as they become confluent, and beta-catenin protein expression increases as 2T3 cells become confluent, reflecting a set of genes involved in early preosteoblast to osteoblast commitment, as observed in vitro and in vivo. Gene Set Enrichment Analysis (GSEA) demonstrated that this 326 dataset is very similar to several early osteoblast geneset signatures. The MLO-Y4 cell model is a well-known in vitro osteocyte model. The MLO-Y4 expression pattern was directly compared with the 2T3 osteoblast cell model. 181 genes that are highly expressed in MLO-Y4 osteocytes compared to osteoblasts were identified. Very few genes expressed in MLO-Y4 cells are found in osteocytes directly isolate from bone, suggesting that osteocyte specific gene programs most likely require the osteocytes to be embedded in the proper mineralized matrix. The MLO-Y4 dataset includes few established in vivo osteocyte markers, but does include several transcription factors such as Vitamin D receptor, Tcf7, and Irx5, whose expression was confirmed in osteocytes in vivo. Gene expression signatures in MLO-Y4 cells, as determined by functional clustering and interaction maps, suggest active prostaglandin-PKA pathways, genes involved in dendrite formation, acute/defense response pathways, TGFbeta signaling, and interferon/chemokine pathways. GSEA demonstrated that MLO-Y4 expression pattern is similar to macrophages, mesenchymal fibroblasts, and early osteoblasts.
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Affiliation(s)
- Wuchen Yang
- Department of Periodontics and Cellular and Structural Biology, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA
| | - Marie A. Harris
- Department of Periodontics and Cellular and Structural Biology, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA
| | - Jelica Gluhak Heinrich
- Department of Orthodontics, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA
| | - Dayong Guo
- Department of Oral Biology, University of Missouri at Kansas City, School of Dentistry, Kansas City, MO 64108, USA
| | - Lynda F. Bonewald
- Department of Oral Biology, University of Missouri at Kansas City, School of Dentistry, Kansas City, MO 64108, USA
| | - Stephen E. Harris
- Department of Periodontics and Cellular and Structural Biology, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA
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17
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Marín MP, Tomas M, Esteban-Pretel G, Megías L, López-Iglesias C, Egea G, Renau-Piqueras J. Chronic ethanol exposure induces alterations in the nucleocytoplasmic transport in growing astrocytes. J Neurochem 2008; 106:1914-28. [DOI: 10.1111/j.1471-4159.2008.05514.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
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18
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Aoto K, Shikata Y, Higashiyama D, Shiota K, Motoyama J. Fetal ethanol exposure activates protein kinase A and impairs Shh expression in prechordal mesendoderm cells in the pathogenesis of holoprosencephaly. ACTA ACUST UNITED AC 2008; 82:224-31. [PMID: 18338389 DOI: 10.1002/bdra.20447] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
BACKGROUND In humans, fetal ethanol exposure can cause holoprosencephaly (HPE), one of the most common birth defects that is characterized by brain, facial, and oral abnormalities. However, the pathogenesis of HPE is not clear. In the present study, we investigated the teratogenic mechanism of ethanol-induced brain and facial malformations in mice. METHODS Pregnant C57BL/6J mice were administered ethanol on E7 and facial and brain malformations were characterized on E10.5. We examined the effect of fetal ethanol exposure on Shh expression and activation of protein kinase A (PKA) because mutations in the human Shh gene are the most frequent cause of autosomal-dominant inherited HPE and PKA is a potent endogenous antagonist of Shh signaling. RESULTS Fetal ethanol exposure on E7 induced severe midline defects characteristic of HPE. Ethanol exposure impaired Shh expression and induced excessive apoptosis only along the anterior edge of the prechordal mesendoderm (PME). In addition, ethanol activated PKA in anterior PME cells. Pretreatment of embryos with antioxidants, such as vitamins C or E, prevented the development of ethanol-induced HPE. CONCLUSIONS Shh expression in PME cells is involved in the pathogenesis of ethanol-induced HPE. Ethanol may impair Shh expression indirectly by activating PKA. The inhibition of excessive apoptosis in PME cells by antioxidants implies that oxidative stress may underlie the teratogenic actions of ethanol. Thus, antioxidant treatment may be a simple preventative measure that could reduce the incidence of HPE following fetal ethanol exposure.
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Affiliation(s)
- Kazushi Aoto
- Molecular Neuropathology Group, Brain Science Institute, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198
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19
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Meoli E, Bossis I, Cazabat L, Mavrakis M, Horvath A, Stergiopoulos S, Shiferaw ML, Fumey G, Perlemoine K, Muchow M, Robinson-White A, Weinberg F, Nesterova M, Patronas Y, Groussin L, Bertherat J, Stratakis CA. Protein kinase A effects of an expressed PRKAR1A mutation associated with aggressive tumors. Cancer Res 2008; 68:3133-41. [PMID: 18451138 PMCID: PMC3129544 DOI: 10.1158/0008-5472.can-08-0064] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Most PRKAR1A tumorigenic mutations lead to nonsense mRNA that is decayed; tumor formation has been associated with an increase in type II protein kinase A (PKA) subunits. The IVS6+1G>T PRKAR1A mutation leads to a protein lacking exon 6 sequences [R1 alpha Delta 184-236 (R1 alpha Delta 6)]. We compared in vitro R1 alpha Delta 6 with wild-type (wt) R1 alpha. We assessed PKA activity and subunit expression, phosphorylation of target molecules, and properties of wt-R1 alpha and mutant (mt) R1 alpha; we observed by confocal microscopy R1 alpha tagged with green fluorescent protein and its interactions with Cerulean-tagged catalytic subunit (C alpha). Introduction of the R1 alpha Delta 6 led to aberrant cellular morphology and higher PKA activity but no increase in type II PKA subunits. There was diffuse, cytoplasmic localization of R1 alpha protein in wt-R1 alpha- and R1 alpha Delta 6-transfected cells but the former also exhibited discrete aggregates of R1 alpha that bound C alpha; these were absent in R1 alpha Delta 6-transfected cells and did not bind C alpha at baseline or in response to cyclic AMP. Other changes induced by R1 alpha Delta 6 included decreased nuclear C alpha. We conclude that R1 alpha Delta 6 leads to increased PKA activity through the mt-R1 alpha decreased binding to C alpha and does not involve changes in other PKA subunits, suggesting that a switch to type II PKA activity is not necessary for increased kinase activity or tumorigenesis.
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Affiliation(s)
- Elise Meoli
- Section on Endocrinology and Genetics, Program in Developmental Endocrinology and Genetics, National Institute of Child Health and Human Development, NIH, Bethesda, Maryland
| | - Ioannis Bossis
- Section on Endocrinology and Genetics, Program in Developmental Endocrinology and Genetics, National Institute of Child Health and Human Development, NIH, Bethesda, Maryland
| | - Laure Cazabat
- Institut National de la Santé et de la Recherche Médicale U567, Département d’Endocrinologie, Métabolisme and Cancer, Institut Cochin
- Centre National de la Recherche Scientifique Unité Mixte de Recherche 8104
- Centre de Référence des Maladies Rares de la Surrénale, Service d’Endocrinologie, Hôpital Cochin, Université Paris 5, Paris, France
| | - Manos Mavrakis
- Section on Organelle Biology, Program in Cell Biology and Metabolism, National Institute of Child Health and Human Development, NIH, Bethesda, Maryland
| | - Anelia Horvath
- Section on Endocrinology and Genetics, Program in Developmental Endocrinology and Genetics, National Institute of Child Health and Human Development, NIH, Bethesda, Maryland
| | - Sotiris Stergiopoulos
- Section on Endocrinology and Genetics, Program in Developmental Endocrinology and Genetics, National Institute of Child Health and Human Development, NIH, Bethesda, Maryland
| | - Miriam L. Shiferaw
- Section on Endocrinology and Genetics, Program in Developmental Endocrinology and Genetics, National Institute of Child Health and Human Development, NIH, Bethesda, Maryland
| | - Glawdys Fumey
- Institut National de la Santé et de la Recherche Médicale U567, Département d’Endocrinologie, Métabolisme and Cancer, Institut Cochin
- Centre National de la Recherche Scientifique Unité Mixte de Recherche 8104
- Centre de Référence des Maladies Rares de la Surrénale, Service d’Endocrinologie, Hôpital Cochin, Université Paris 5, Paris, France
| | - Karine Perlemoine
- Institut National de la Santé et de la Recherche Médicale U567, Département d’Endocrinologie, Métabolisme and Cancer, Institut Cochin
- Centre National de la Recherche Scientifique Unité Mixte de Recherche 8104
- Centre de Référence des Maladies Rares de la Surrénale, Service d’Endocrinologie, Hôpital Cochin, Université Paris 5, Paris, France
| | - Michael Muchow
- Section on Endocrinology and Genetics, Program in Developmental Endocrinology and Genetics, National Institute of Child Health and Human Development, NIH, Bethesda, Maryland
| | - Audrey Robinson-White
- Section on Endocrinology and Genetics, Program in Developmental Endocrinology and Genetics, National Institute of Child Health and Human Development, NIH, Bethesda, Maryland
| | - Frank Weinberg
- Section on Endocrinology and Genetics, Program in Developmental Endocrinology and Genetics, National Institute of Child Health and Human Development, NIH, Bethesda, Maryland
| | - Maria Nesterova
- Section on Endocrinology and Genetics, Program in Developmental Endocrinology and Genetics, National Institute of Child Health and Human Development, NIH, Bethesda, Maryland
| | - Yianna Patronas
- Section on Endocrinology and Genetics, Program in Developmental Endocrinology and Genetics, National Institute of Child Health and Human Development, NIH, Bethesda, Maryland
| | - Lionel Groussin
- Institut National de la Santé et de la Recherche Médicale U567, Département d’Endocrinologie, Métabolisme and Cancer, Institut Cochin
- Centre National de la Recherche Scientifique Unité Mixte de Recherche 8104
- Centre de Référence des Maladies Rares de la Surrénale, Service d’Endocrinologie, Hôpital Cochin, Université Paris 5, Paris, France
| | - Jérôme Bertherat
- Institut National de la Santé et de la Recherche Médicale U567, Département d’Endocrinologie, Métabolisme and Cancer, Institut Cochin
- Centre National de la Recherche Scientifique Unité Mixte de Recherche 8104
- Centre de Référence des Maladies Rares de la Surrénale, Service d’Endocrinologie, Hôpital Cochin, Université Paris 5, Paris, France
| | - Constantine A. Stratakis
- Section on Endocrinology and Genetics, Program in Developmental Endocrinology and Genetics, National Institute of Child Health and Human Development, NIH, Bethesda, Maryland
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20
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Immunocytochemical analysis of cyclic AMP receptor proteins in the developing rat parotid gland. Arch Oral Biol 2008; 53:429-36. [PMID: 18187105 DOI: 10.1016/j.archoralbio.2007.11.012] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2007] [Revised: 10/23/2007] [Accepted: 11/26/2007] [Indexed: 11/20/2022]
Abstract
UNLABELLED Previous studies showed that regulatory subunits of type II cyclic AMP-dependent protein kinase (RII) are present in adult rat parotid acinar cells, and are secreted into saliva. If the synthesis and intracellular distribution of RII exhibit developmental specificity, then RII can be an indicator of secretory and regulatory activity of salivary glands. OBJECTIVE To determine the expression and distribution of RII in the rat parotid at specific ages representing defined developmental stages. METHODS Parotid glands of fetal, neonatal and adult rats were prepared for morphologic and immunocytochemical study. The cellular distribution of RII was studied using light microscopic immunogold silver staining with anti-RII, and its intracellular distribution using electron microscopic immunogold labeling. RESULTS In utero, parotid RII levels were low; 5-18 days after birth, labeling of secretory granules and cytoplasm rose to a peak, followed by a rapid decrease in both compartments at 25 days. At 60 days, granule labeling increased to levels near those at 18 days, whereas cytoplasmic labeling remained low. Nuclear labeling was highest during the first 3 weeks after birth, and then declined. CONCLUSIONS The higher nuclear and cytoplasmic labeling during the neonatal period may reflect RII involvement in acinar cell differentiation. The accumulation of RII in secretory granules is similar to the pattern of the major salivary proteins, amylase and PSP. The redistribution of RII in these compartments during development may reflect changing gene expression patterns, and may be useful for identification of genetic or metabolic abnormalities.
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21
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Repunte-Canonigo V, Lutjens R, van der Stap LD, Sanna PP. Increased expression of protein kinase A inhibitor alpha (PKI-alpha) and decreased PKA-regulated genes in chronic intermittent alcohol exposure. Brain Res 2007; 1138:48-56. [PMID: 17270154 PMCID: PMC4485929 DOI: 10.1016/j.brainres.2006.09.115] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2006] [Revised: 09/19/2006] [Accepted: 09/29/2006] [Indexed: 11/17/2022]
Abstract
Intermittent models of alcohol exposure that mimic human patterns of alcohol consumption produce profound physiological and biochemical changes and induce rapid increases in alcohol self-administration. We used high-density oligonucleotide microarrays to investigate gene expression changes during chronic intermittent alcohol exposure in three brain regions that receive mesocorticolimbic dopaminergic projections and that are believed to be involved in alcohol's reinforcing actions: the medial prefrontal cortex, the nucleus accumbens and the amygdala. An independent replication of the experiment was used for RT-PCR validation of the microarray results. The protein kinase A inhibitor alpha (PKI-alpha, Pkia), a member of the endogenous PKI family implicated in reducing nuclear PKA activity, was found to be increased in all three regions tested. Conversely, we observed a downregulation of the expression of several PKA-regulated transcripts in one or more of the brain regions studied, including the activity and neurotransmitter-regulated early gene (Ania) - 1, -3, -7, -8, the transcription factors Egr1 and NGFI-B (Nr4a1) and the neuropeptide NPY. Reduced expression of PKA-regulated genes in mesocorticolimbic projection areas may have motivational significance in the rapid increase in alcohol self-administration induced by intermittent alcohol exposure.
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Affiliation(s)
- Vez Repunte-Canonigo
- Molecular and Integrative Neuroscience Department and San Diego Alcohol Research Center, The Scripps Research Institute, La Jolla, CA, 92103, USA
| | - Robert Lutjens
- Molecular and Integrative Neuroscience Department and San Diego Alcohol Research Center, The Scripps Research Institute, La Jolla, CA, 92103, USA
| | - Lena D. van der Stap
- Molecular and Integrative Neuroscience Department and San Diego Alcohol Research Center, The Scripps Research Institute, La Jolla, CA, 92103, USA
| | - Pietro Paolo Sanna
- Molecular and Integrative Neuroscience Department and San Diego Alcohol Research Center, The Scripps Research Institute, La Jolla, CA, 92103, USA
- To whom correspondence should be addressed ()
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22
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Rath GM, Schneider C, Dedieu S, Sartelet H, Morjani H, Martiny L, El Btaouri H. Thrombospondin-1 C-terminal-derived peptide protects thyroid cells from ceramide-induced apoptosis through the adenylyl cyclase pathway. Int J Biochem Cell Biol 2006; 38:2219-28. [PMID: 16971166 DOI: 10.1016/j.biocel.2006.07.004] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2006] [Revised: 07/17/2006] [Accepted: 07/18/2006] [Indexed: 01/28/2023]
Abstract
Thrombospondin-1, a multi-modular matrix protein is able to interact with a variety of matrix proteins and cell-surface receptors. Thus it is multifunctional. In this work, we examined the role of thrombospondin-1 in ceramide-induced thyroid apoptosis. We focused on the VVM containing sequence localized in the C-terminal domain of the molecule. Primary cultured thyroid cells synthesize thrombospondin-1 depending on their morphological organization. As it leads thyrocytes to organize into monolayers before inducing apoptosis ceramide can modulate this organization. Here, we established that C(2)-ceramide treatment decreased thrombospondin-1 expression by interfering with the adenylyl cyclase pathway, thus leading to apoptosis. Furthermore, we demonstrated that the thrombospondin-1-derived peptide 4N1 (RFYVVMWK) abolished ceramide-induced thyroid cell death by preventing intracellular cAMP levels from dropping. Finally, we reported that 4N1-mediated inhibition of ceramide-induced apoptosis was consistently associated with a down-regulation of the caspase-3 processing. Integrin-associated protein receptor (IAP or CD47) was identified as a molecular relay mediating the observed 4N1 effects. Taken together, our results shed light for the first time on anti-apoptotic activities of the thrombospondin-1-derived peptide 4N1 and provide new information on how thrombospondin-1 may control apoptosis of non-tumoral cells.
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Affiliation(s)
- G M Rath
- UMR-CNRS 6198 Matrice Extracellulaire et Régulation Cellulaire, UFR Sciences de Reims, IFR 53, 51687 Reims Cedex 2, France.
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23
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Asyyed A, Storm D, Diamond I. Ethanol activates cAMP response element-mediated gene expression in select regions of the mouse brain. Brain Res 2006; 1106:63-71. [PMID: 16854384 DOI: 10.1016/j.brainres.2006.05.107] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2006] [Revised: 05/19/2006] [Accepted: 05/24/2006] [Indexed: 11/18/2022]
Abstract
UNLABELLED The specific brain regions that contribute to behavioral changes produced by ethanol are not clearly understood. We know that cAMP-PKA signaling has been strongly implicated in the CNS effects of ethanol. Ethanol promotes activation and translocation of the PKA catalytic subunit (Calpha) into the nucleus in cell lines and primary neuronal cultures. PKA Calpha translocation to the nucleus is followed by cAMP Response Element protein phosphorylation (pCREB) and cAMP Response Element (CRE)-mediated gene expression. Here, we use X-gal histochemistry to map CRE-mediated gene transcription in the brain of CRE-lacZ transgenic mice following ethanol injection. RESULTS 3 h after i.p. ethanol injection (3.2 g/kg, 16% wt/vol.), the number of X-gal positive cells was increased in the nucleus accumbens (202 +/- 63 cells/field compared to 71 +/- 47 cells/field in saline injected controls, P < 0.05 by paired t-test, n = 10). Similar increases were found in other mesolimbic areas and brain regions associated with rewarding and addictive responses. These include: prefrontal cortex, lateral and medial septum, basolateral amygdala, paraventricular and anterior hypothalamus, centromedial thalamus, CA1 region of hippocampus and dentate gyrus, substantia nigra pars compacta, ventral tegmental area, geniculate nucleus and the superior colliculus. CONCLUSION these results confirm and extend current concepts that ethanol stimulates cAMP-PKA signaling in brain regions involved in CNS responses to ethanol.
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MESH Headings
- Alcohol-Induced Disorders, Nervous System/genetics
- Alcohol-Induced Disorders, Nervous System/metabolism
- Alcohol-Induced Disorders, Nervous System/physiopathology
- Animals
- Brain/anatomy & histology
- Brain/drug effects
- Brain/metabolism
- Brain Chemistry/drug effects
- Brain Chemistry/genetics
- Central Nervous System Depressants/pharmacology
- Cyclic AMP/metabolism
- Cyclic AMP Response Element-Binding Protein/genetics
- Cyclic AMP-Dependent Protein Kinases/drug effects
- Cyclic AMP-Dependent Protein Kinases/metabolism
- Disease Models, Animal
- Ethanol/pharmacology
- Female
- Galactosides
- Gene Expression Regulation/drug effects
- Gene Expression Regulation/physiology
- Genes, Reporter/drug effects
- Genes, Reporter/physiology
- Indoles
- Lac Operon/drug effects
- Lac Operon/genetics
- Limbic System/anatomy & histology
- Limbic System/drug effects
- Limbic System/metabolism
- Male
- Mice
- Mice, Inbred C57BL
- Mice, Transgenic
- RNA, Messenger/drug effects
- RNA, Messenger/metabolism
- Reward
- Signal Transduction/drug effects
- Signal Transduction/physiology
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Affiliation(s)
- Asma Asyyed
- Ernest Gallo Clinic and Research Center, Department of Neurology, University of California, San Francisco, 5858 Horton St., Ste. 200, Emeryville, CA 94608, USA.
| | - Daniel Storm
- Department of Pharmacology, University of Washington, Seattle, WA 98195, USA
| | - Ivan Diamond
- Ernest Gallo Clinic and Research Center, Department of Neurology, University of California, San Francisco, 5858 Horton St., Ste. 200, Emeryville, CA 94608, USA; Department of Neuroscience, CV Therapeutics, Palo Alto, CA 94304, USA
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24
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Askari MDF, Tsao MS, Cekanova M, Schuller HM. Ethanol and the tobacco-specific carcinogen, NNK, contribute to signaling in immortalized human pancreatic duct epithelial cells. Pancreas 2006; 33:53-62. [PMID: 16804413 DOI: 10.1097/01.mpa.0000226883.55828.e9] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
OBJECTIVES Smoking is a well-documented risk factor for pancreatic cancer. The tobacco-specific nitrosamine, NNK (4-[methylnitrosamino]-1-[3-pyridyl]-1-butanone), significantly induces pancreatic ductal adenocarcinomas in laboratory rodents. Recent observations suggest that ethanol enhances the tumorigenic effects of smoking. Ethanol consumption is associated with the development of chronic pancreatitis, also considered a predisposing factor for pancreatic ductal adenocarcinoma. Because the precise role of ethanol in pancreatic carcinogenesis is not known, this study sought to elucidate the cumulative effects of ethanol and NNK on particular signal transduction pathways that might play a role in cell proliferation in immortalized human pancreatic duct epithelial cells. METHODS The HPDE6-c7 cells are developed from pancreatic duct epithelial cells, which are the putative cells of origin of pancreatic ductal adenocarcinoma. Cell proliferation assays, Western blot, and cyclic adenosine monophosphate assays were used to demonstrate the effects of ethanol and NNK treatments on these cells. RESULTS Ethanol cotreatments enhanced the NNK-induced proliferation of these cells. This response was inhibited by the adenylyl cyclase, protein kinase A, mitogen-activated protein kinase (p42/p44), and epidermal growth factor receptor-specific tyrosine kinase inhibitors. Cotreatments of NNK and ethanol also increased cyclic adenosine monophosphate accumulation, cAMP response element-binding family of proteins and mitogen-activated protein kinase phosphorylation, and protein kinase A activation. CONCLUSIONS These findings suggest a potential role for these pathways contributing to the development of smoking- and alcohol-related pancreatic carcinogenesis.
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Affiliation(s)
- Minoo D F Askari
- Experimental Oncology Laboratory, Department of Pathobiology, College of Veterinary Medicine, University of Tennessee, Knoxville, TN 37996, USA
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25
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Maas JW, Vogt SK, Chan GCK, Pineda VV, Storm DR, Muglia LJ. Calcium-stimulated adenylyl cyclases are critical modulators of neuronal ethanol sensitivity. J Neurosci 2006; 25:4118-26. [PMID: 15843614 PMCID: PMC6724953 DOI: 10.1523/jneurosci.4273-04.2005] [Citation(s) in RCA: 92] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The importance of the cAMP signaling pathway in the modulation of ethanol sensitivity has been suggested by studies in organisms from Drosophila melanogaster to man. However, the involvement of specific isoforms of adenylyl cyclase (AC), the molecule that converts ATP to cAMP, has not been systemically determined in vivo. Because AC1 and AC8 are the only AC isoforms stimulated by calcium, and ethanol modulates calcium flux by the NMDA receptor, we hypothesized that these ACs would be important in the neural response to ethanol. AC1 knock-out (KO) mice and double knock-out (DKO) mice with genetic deletion of both AC1 and AC8 display substantially increased sensitivity to ethanol-induced sedation compared with wild-type (WT) mice, whereas AC8 KO mice are only minimally more sensitive. In contrast, AC8 KO and DKO mice, but not AC1 KO mice, demonstrate decreased voluntary ethanol consumption compared with WT mice. DKO mice do not display increased sleep time compared with WT mice after administration of ketamine or pentobarbital, indicating that the mechanism of enhanced ethanol sensitivity in these mice is likely distinct from the antagonism of ethanol of the NMDA receptor and potentiation of the GABA(A) receptor. Ethanol does not enhance calcium-stimulated AC activity, but the ethanol-induced phosphorylation of a discrete subset of protein kinase A (PKA) substrates is compromised in the brains of DKO mice. These results indicate that the unique activation of PKA signaling mediated by the calcium-stimulated ACs is an important component of the neuronal response to ethanol.
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Affiliation(s)
- James W Maas
- Department of Pediatrics and Molecular Biology and Pharmacology, Washington University School of Medicine, St. Louis, Missouri 63110, USA
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26
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Wand G. The anxious amygdala: CREB signaling and predisposition to anxiety and alcoholism. J Clin Invest 2005; 115:2697-9. [PMID: 16200206 PMCID: PMC1236699 DOI: 10.1172/jci26436] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
The amygdala is believed to play a key role in assigning emotional significance to specific sensory input, and conditions such as anxiety, autism, stress, and phobias are thought to be linked to its abnormal function. Growing evidence has also implicated the amygdala in mediation of the stress-dampening properties of alcohol. In this issue of the JCI, Pandey and colleagues identify a central amygdaloid signaling pathway involved in anxiety-like and alcohol-drinking behaviors in rats. They report that decreased phosphorylation of cAMP responsive element-binding protein (CREB) resulted in decreased neuropeptide Y (NPY) expression in the central amygdala of alcohol-preferring rats, causing high anxiety-like behavior. Alcohol intake by these animals was shown to increase PKA-dependent CREB phosphorylation and thereby NPY expression, subsequently ameliorating anxiety-like behavior. These provocative data suggest that a CREB-dependent neuromechanism underlies high anxiety-like and excessive alcohol-drinking behavior.
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Affiliation(s)
- Gary Wand
- Department of Medicine and Psychiatry, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA.
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27
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Abstract
Drug addiction is a chronic disease characterized by compulsive drug use despite the severe negative consequences associated with it. Repeated exposure to drugs of abuse results in molecular adaptations in neuronal signaling pathways, which eventually manifest in the complex behavioral alterations that characterize addiction. These include tolerance, sensitization, dependence, drug craving, and relapse. In this Review, we focus on recent studies highlighting signaling cascades initiated by cocaine, as a representative of a drug of abuse with a defined site of action, and alcohol, as a drug with an undefined primary site of action. Specifically, we describe recent studies that emphasize the role of protein-protein interactions, phosphorylation, and compartmentalization in the molecular mechanisms that result in the cellular and behavioral adaptations that underlie addiction. Signaling cascades that contribute to addiction, as well as those that protect or delay the development of addiction, are presented.
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Affiliation(s)
- Dorit Ron
- Ernest Gallo Clinic and Research Center, University of California San Francisco, Emeryville, CA 94608, USA.
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28
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Newton PM, Messing RO. Intracellular signaling pathways that regulate behavioral responses to ethanol. Pharmacol Ther 2005; 109:227-37. [PMID: 16102840 DOI: 10.1016/j.pharmthera.2005.07.004] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2005] [Accepted: 07/13/2005] [Indexed: 10/25/2022]
Abstract
Recent evidence indicates that ethanol modulates the function of specific intracellular signaling cascades, including those that contain cyclic adenosine 3', 5'-monophosphate (cAMP)-dependent protein kinase A (PKA), protein kinase C (PKC), the tyrosine kinase Fyn, and phospholipase D (PLD). In some cases, the specific components of these cascades appear to mediate the effects of ethanol, whereas other components indirectly modify responses to ethanol. Studies utilizing selective inhibitors and genetically modified mice have identified specific isoforms of proteins involved in responses to ethanol. The effects of ethanol on neuronal signaling appear restricted to certain brain regions, partly due to the restricted distribution of these proteins. This likely contributes specificity to ethanol's actions on behavior. This review summarizes recent work on ethanol and intracellular signal transduction, emphasizing studies that have identified specific molecular events that underlie behavioral responses to ethanol.
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Affiliation(s)
- P M Newton
- The Ernest Gallo Clinic and Research Center, Department of Neurology, University of California at San Francisco, 5858 Horton Street, Suite 200, Emeryville, CA 94608, United States
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Ethanol Effects on Dopaminergic ???Reward??? Neurons in the Ventral Tegmental Area and the Mesolimbic Pathway. Alcohol Clin Exp Res 2004. [DOI: 10.1097/01.alc.0000145976.64413.21] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Medina AE, Krahe TE, Ramoa AS. Early alcohol exposure induces persistent alteration of cortical columnar organization and reduced orientation selectivity in the visual cortex. J Neurophysiol 2004; 93:1317-25. [PMID: 15483067 DOI: 10.1152/jn.00714.2004] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Fetal alcohol syndrome (FAS) is a major cause of learning and sensory deficits in children. The visual system in particular is markedly affected, with an elevated prevalence of poor visual perceptual skills. Developmental problems involving the neocortex are likely to make a major contribution to some of these abnormalities. Neuronal selectivity to stimulus orientation, a functional property thought to be crucial for normal vision, may be especially vulnerable to alcohol exposure because it starts developing even before eye opening. To address this issue, we examined the effects of early alcohol exposure on development of cortical neuron orientation selectivity and organization of cortical orientation columns. Ferrets were exposed to ethanol starting at postnatal day (P) 10, when the functional properties and connectivity of neocortical neurons start to develop. Alcohol exposure ended at P30, just before eye opening at P32. Following a prolonged alcohol-free period (15-35 days), long-term effects of early alcohol exposure on cortical orientation selectivity were examined at P48-P65, when orientation selectivity in normal ferret cortex has reached a mature state. Optical imaging of intrinsic signals revealed decreased contrast of orientation maps in alcohol- but not saline-treated animals. Moreover, single-unit recordings revealed that early alcohol treatment weakened neuronal orientation selectivity while preserving robust visual responses. These findings indicate that alcohol exposure during a brief period of development disrupts cortical processing of sensory information at a later age and suggest a neurobiological substrate for some types of sensory deficits in FAS.
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Affiliation(s)
- Alexandre E Medina
- Deptartment of Anatomy and Neurobiology, Virginia Commonwealth University Medical Center, Box 0709, 1101 East Marshall St., Rm. 12-042, Richmond, VA 23298-0709, USA
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Tencza SB, Sipe MA. Detection and classi?cation of threat agents via high-content assays of mammalian cells. J Appl Toxicol 2004; 24:371-7. [PMID: 15478183 DOI: 10.1002/jat.1025] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
One property common to all chemical or biological threat agents is that they damage mammalian cells. A threat detection and classification method based on the effects of compounds on cells has been developed. This method employs high-content screening (HCS), a concept in drug discovery that enables those who practice cell-based assays to generate deeper biological information about the compounds they are testing. A commercial image-based cell screening platform comprising fluorescent reagents, automated image acquisition hardware, image analysis algorithms, data management and informatics was used to develop assays and detection/classification methods for threat agents. These assays measure a cell's response to a compound, which may include activation or inhibition of signal transduction pathways, morphological changes or cytotoxic effects. Data on cell responses to a library of compounds was collected and used as a training set. At the EILATox-Oregon Workshop, cellular responses following exposure to unknown samples were measured by conducting assays of p38 MAP kinase, NF-kappaB, extracellular-signal related kinase (ERK) MAP kinase, cyclic AMP-response element binding protein (CREB), cell permeability, lysosomal mass and nuclear morphology. Although the assays appeared to perform well, only four of the nine toxic samples were detected. However the system was specific, because no false positives were detected. Opportunities for improvement to the system were identified during the course of this enlightening workshop. Some of these improvements were applied in subsequent tests in the Cellomics laboratories, resulting in a higher level of detection. Thus, an HCS approach was shown to have potential in detecting threat agents, but additional work is necessary to make this a comprehensive detection and classification system.
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Affiliation(s)
- Sarah B Tencza
- Cellomics Inc., 100 Technology Drive, Pittsburgh, PA 15219, USA
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Constantinescu A, Wu M, Asher O, Diamond I. cAMP-dependent protein kinase type I regulates ethanol-induced cAMP response element-mediated gene expression via activation of CREB-binding protein and inhibition of MAPK. J Biol Chem 2004; 279:43321-9. [PMID: 15299023 DOI: 10.1074/jbc.m406994200] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
We have shown that the two types of cAMP-dependent protein kinase (PKA) in NG108-15 cells differentially mediate forskolin- and ethanol-induced cAMP response element (CRE)-binding protein (CREB) phosphorylation and CRE-mediated gene transcription. Activated type II PKA is translocated into the nucleus where it phosphorylates CREB. By contrast, activated type I PKA does not translocate to the nucleus but is required for CRE-mediated gene transcription by inducing the activation of other transcription cofactors such as CREB-binding protein (CBP). We show here that CBP is required for forskolin- and ethanol-induced CRE-mediated gene expression. Forskolin- and ethanol-induced CBP phosphorylation, demonstrable at 10 min, persists up to 24 h. CBP phosphorylation requires type I PKA but not type II PKA. In NG108-15 cells, ethanol and forskolin activation of type I PKA also inhibits several components of the MAPK pathway including B-Raf kinase, ERK1/2, and p90RSK phosphorylation. As a result, unphosphorylated p90RSK no longer binds to nor inhibits CBP. Moreover, MEK inhibition by PD98059 induces a significant increase of CRE-mediated gene activation. Taken together, our findings suggest that inhibition of the MAPK pathway enhances cAMP-dependent gene activation during exposure of NG108-15 cells to ethanol. This mechanism appears to involve type I PKA-dependent phosphorylation of CBP and inhibition of MEK-dependent phosphorylation of p90RSK. Under these conditions p90RSK is no longer bound to CBP, thereby promoting CBP-dependent CREB-mediated gene expression.
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Affiliation(s)
- Anastasia Constantinescu
- Ernest Gallo Clinic and Research Center, Department of Neurology, University of California, San Francisco, Emeryville, CA 94608, USA.
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Vagts AJ, He DY, Yaka R, Ron D. Cellular adaptation to chronic ethanol results in altered compartmentalization and function of the scaffolding protein RACK1. Alcohol Clin Exp Res 2004; 27:1599-605. [PMID: 14574230 DOI: 10.1097/01.alc.0000089957.63597.a4] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND Previously, we found that acute ethanol induces the translocation of the scaffolding protein RACK1 to the nucleus. Recently, we found that nuclear RACK1 mediates acute ethanol induction of immediate early gene c-fos expression. Alterations in gene expression are thought to lead to long-term changes that ultimately contribute to the development of alcohol addiction and toxicity. Therefore, we sought to determine the effects of chronic exposure of cells to ethanol on the cellular compartmentalization of RACK1 and on c-fos messenger RNA (mRNA) and protein expression. METHODS Rat C6 glioma cells were used as the cell culture model. Immunohistochemistry was implemented to visualize the localization of RACK1 and to monitor the protein level of c-fos. Reverse-transcription polymerase chain reaction was used to measure c-fos mRNA levels. The Tat-protein transduction method was used to transduce recombinant Tat-RACK1 into cells as previously described. RESULTS Chronic exposure of cells to 200 mM ethanol for 24 and 48 hr resulted in the gradual re-distribution of RACK1 out of the nucleus. It is interesting to note that acute ethanol re-challenge immediately after chronic treatment did not result in RACK1 translocation to the nucleus, and nuclear compartmentalization of RACK1 in response to acute ethanol was detected only after 24 hr of withdrawal. Similar patterns were obtained for c-fos expression. Chronic exposure to ethanol did not result in an increase in mRNA or protein levels of c-fos. Furthermore, acute ethanol exposure did not increase c-fos protein levels in cells that were first treated chronically with ethanol. However, transduction of exogenous RACK1 expressed as a Tat-fusion protein was able to rescue c-fos mRNA expression after chronic ethanol exposure. CONCLUSIONS Our data suggest that RACK1 nuclear compartmentalization and ethanol-induced c-fos expression are transient and are desensitized to ethanol during prolonged exposure to high concentrations. The desensitization is temporary, and RACK1 can respond to acute ethanol treatment after a 24-hr withdrawal period. Our data further suggest that the altered compartmentalization of RACK1 leads to differences in c-fos expression upon acute or chronic exposure to ethanol. In summary, RACK1 is an important molecular mediator of the acute and chronic actions of ethanol on the expression of c-fos. These findings could have implications for the molecular signaling pathways leading to pathologic states associated with alcoholism, including toxicity.
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Affiliation(s)
- Alicia J Vagts
- Ernest Gallo Clinic and Research Center, Department of Neurology, University of California, San Francisco, Emeryville, California, USA
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Elliott MR, Shanks RA, Khan IU, Brooks JW, Burkett PJ, Nelson BJ, Kyttaris V, Juang YT, Tsokos GC, Kammer GM. Down-Regulation of IL-2 Production in T Lymphocytes by Phosphorylated Protein Kinase A-RIIβ. THE JOURNAL OF IMMUNOLOGY 2004; 172:7804-12. [PMID: 15187164 DOI: 10.4049/jimmunol.172.12.7804] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The beta isoform of the type II regulatory subunit (RIIbeta) of protein kinase A suppresses CREB transcriptional activity and c-Fos production in T cells following activation via the TCR. Because CREB is an integral nuclear transcription factor for IL-2 production by T cells, we tested the hypothesis that RIIbeta down-regulates IL-2 expression and IL-2 production in T cells. Stable transfection of RIIbeta in Jurkat T cells led to an approximately 90% reduction in IL-2 mRNA and IL-2 protein following T cell activation. The inhibition of IL-2 production was associated with phosphorylation of the RIIbeta subunit at serine 114 (pRIIbeta) and localization of pRIIbeta in intranuclear clusters. A serine 114 phosphorylation-defective mutant, RIIbeta(S114A), did not form these intranuclear clusters as well as wild-type RIIbeta, and did not inhibit IL-2 mRNA and protein synthesis, indicating that serine 114 phosphorylation is required for both nuclear localization and down-regulation of IL-2 production by RIIbeta. In contrast to its effect on IL-2, RIIbeta induced constitutive up-regulation of CD154 mRNA and cell surface expression. Thus, pRIIbeta differentially regulates gene expression following T cell activation. Unexpectedly, we also found that stable overexpression of another protein kinase A regulatory subunit, RIalpha, had the opposite effect on IL-2 expression, causing a 3- to 4-fold increase in IL-2 production following stimulation. In summary, our data demonstrate a novel mechanism by which serine 114 phosphorylation and nuclear localization of RIIbeta controls the regulation of gene expression in T cells.
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Affiliation(s)
- Michael R Elliott
- Department of Microbiology and Immunology, Wake Forest University School of Medicine, Medical Center Boulevard, Winston-Salem, NC 27157, USA
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Abstract
Neuronal responses to alcohol involve several hormone- and neurotransmitter-activated signal transduction pathways. Recent studies suggest that the adenosine A2 receptor (A2) mediates important actions of alcohol. Ethanol inhibits adenosine reuptake, increases extracellular adenosine, and promotes activation of A2. This leads to enhanced cAMP/protein kinase A (PKA) signaling ranging from increases in cAMP to stimulation of cAMP-dependent cAMP response element (CRE)-mediated gene expression. Medium spiny neurons in the striatum/nucleus accumbens (NAc) express A2 and dopamine D2 receptor (D2) on the same cells. Studies in model neuronal cell lines and primary neurons in culture expressing A2 and D2 provide evidence for synergy between ethanol/A2 and D2. Subthreshold concentrations of ethanol or a D2 agonist, without effect separately, synergistically activate cAMP/PKA signaling. Thus, neurons expressing A2 and D2 on the same cells, like in the NAc, are characterized by hypersensitivity to ethanol with a simultaneous activation of dopaminergic signaling. Synergy requires adenosine and appears to be mediated by the release of free betagamma dimers from G(i/o) via D2 activation. The release of free betagamma has pathophysiological significance in the drinking animal because specific blockade of betagamma signaling in the NAc strikingly reduces voluntary alcohol consumption. These findings suggest that signaling pathways, which regulate synergy between A2 and D2, might contain molecular targets for the prevention and treatment of alcoholism and alcohol abuse.
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Affiliation(s)
- William S Mailliard
- Ernest Gallo Clinic and Research Center, University of California, San Francisco, 5858 Horton Street, Suite 200, , Emeryville, CA 94608, USA
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Abstract
Chronic ethanol abuse is associated with liver injury, neurotoxicity, hypertension, cardiomyopathy, modulation of immune responses and increased risk for cancer, whereas moderate alcohol consumption exerts protective effect on coronary heart disease. However, the signal transduction mechanisms underlying these processes are not well understood. Emerging evidences highlight a central role for mitogen activated protein kinase (MAPK) family in several of these effects of ethanol. MAPK signaling cascade plays an essential role in the initiation of cellular processes such as proliferation, differentiation, development, apoptosis, stress and inflammatory responses. Modulation of MAPK signaling pathway by ethanol is distinctive, depending on the cell type; acute or chronic; normal or transformed cell phenotype and on the type of agonist stimulating the MAPK. Acute exposure to ethanol results in modest activation of p42/44 MAPK in hepatocytes, astrocytes, and vascular smooth muscle cells. Acute ethanol exposure also results in potentiation or prolonged activation of p42/44MAPK in an agonist selective manner. Acute ethanol treatment also inhibits serum stimulated p42/44 MAPK activation and DNA synthesis in vascular smooth muscle cells. Chronic ethanol treatment causes decreased activation of p42/44 MAPK and inhibition of growth factor stimulated p42/44 MAPK activation and these effects of ethanol are correlated to suppression of DNA synthesis, impaired synaptic plasticity and neurotoxicity. In contrast, chronic ethanol treatment causes potentiation of endotoxin stimulated p42/44 MAPK and p38 MAPK signaling in Kupffer cells leading to increased synthesis of tumor necrosis factor. Acute exposure to ethanol activates pro-apoptotic JNK pathway and anti-apoptotic p42/44 MAPK pathway. Apoptosis caused by chronic ethanol treatment may be due to ethanol potentiation of TNF induced activation of p38 MAPK. Ethanol induced activation of MAPK signaling is also involved in collagen expression in stellate cells. Ethanol did not potentiate serum stimulated or Gi-protein dependent activation of p42/44 MAPK in normal hepatocytes but did so in embryonic liver cells and transformed hepatocytes leading to enhanced DNA synthesis. Ethanol has a 'triangular effect' on MAPK that involve direct effects of ethanol, its metabolically derived mediators and oxidative stress. Acetaldehyde, phosphatidylethanol, fatty acid ethyl ester and oxidative stress, mediate some of the effects seen after ethanol alone whereas ethanol modulation of agonist stimulated MAPK signaling appears to be mediated by phosphatidylethanol. Nuclear MAPKs are also affected by ethanol. Ethanol modulation of nuclear p42/44 MAPK occurs by both nuclear translocation of p42/44 MAPK and its activation in the nucleus. Of interest is the observation that ethanol caused selective acetylation of Lys 9 of histone 3 in the hepatocyte nucleus. It is plausible that ethanol modulation of cross talk between phosphorylation and acetylations of histone may regulate chromatin remodeling. Taken together, these recent developments place MAPK in a pivotal position in relation to cellular actions of ethanol. Furthermore, they offer promising insights into the specificity of ethanol effects and pharmacological modulation of MAPK signaling. Such molecular signaling approaches have the potential to provide mechanism-based therapy for the management of deleterious effects of ethanol or for exploiting its beneficial effects.
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Affiliation(s)
- Annayya R Aroor
- Department of Medical Pharmacology and Physiology, School of Medicine, University of Missouri, Columbia, MO 65212, USA.
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Abstract
Neurobiological actions of ethanol have been linked to perturbations in cyclic AMP (cAMP)-dependent signaling processes. Chronic ethanol exposure leads to desensitization of cAMP production in response to physiological ligands (heterologous desensitization). Ethanol-induced alterations in neuronal expression of G proteins G(s) and G(i) have been invoked as a cause of heterologous desensitization. However, effects of ethanol on G protein expression vary considerably among different experimental protocols, various brain regions and diverse neuronal cell types. Dynamic palmitoylation of G protein alpha subunits is critical for membrane localization and protein-protein interactions, and represents a regulatory feature of G protein function. We studied the effect of ethanol on G alpha(s) palmitoylation. In NG108-15 rat neuroblastoma x glioma hybrid cells, acute exposure to pharmacologically relevant concentrations of ethanol (25-100 mm) inhibited basal and prostaglandin E1-stimulated incorporation of palmitate into G alpha(s). Exposure of NG108-15 cells to ethanol for 72 h induced a shift in G alpha(s) to its non-palmitoylated state, coincident with an inhibition of prostaglandin E1-induced cAMP production. Both parameters were restored following 24 h of ethanol withdrawal. Chronic ethanol exposure also induced the depalmitoylation of G alpha(s) in human embryonic kidney (HEK)293 cells that overexpress wild-type G alpha(s) and caused heterologous desensitization of adenylyl cyclase. By contrast, HEK293 cells that express a non-palmitoylated mutant of G alpha(s) were insensitive to heterologous desensitization after chronic ethanol exposure. In summary, the findings identify a novel effect of ethanol on post-translational lipid modification of G alpha(s), and represent a mechanism by which ethanol might affect adenylyl cyclase activity.
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Affiliation(s)
- Hazem Hallak
- Department of Pathology, Anatomy and Cell Biology, Jefferson Medical College, Thomas Jefferson University, Philadelphia, Pennsylvania 19107-5541, USA.
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Zippin JH, Farrell J, Huron D, Kamenetsky M, Hess KC, Fischman DA, Levin LR, Buck J. Bicarbonate-responsive "soluble" adenylyl cyclase defines a nuclear cAMP microdomain. ACTA ACUST UNITED AC 2004; 164:527-34. [PMID: 14769862 PMCID: PMC2172001 DOI: 10.1083/jcb.200311119] [Citation(s) in RCA: 133] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Bicarbonate-responsive “soluble” adenylyl cyclase resides, in part, inside the mammalian cell nucleus where it stimulates the activity of nuclear protein kinase A to phosphorylate the cAMP response element binding protein (CREB). The existence of this complete and functional, nuclear-localized cAMP pathway establishes that cAMP signals in intracellular microdomains and identifies an alternate pathway leading to CREB activation.
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Affiliation(s)
- Jonathan H Zippin
- Department of Pharmacology, Joan and Sanford I. Weill Medical College and Graduate School of Medical Sciences of Cornell University, 1300 York Ave., New York, NY 10021, USA
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Elliott MR, Tolnay M, Tsokos GC, Kammer GM. Protein kinase A regulatory subunit type II beta directly interacts with and suppresses CREB transcriptional activity in activated T cells. THE JOURNAL OF IMMUNOLOGY 2004; 171:3636-44. [PMID: 14500661 DOI: 10.4049/jimmunol.171.7.3636] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Levels of the type IIbeta regulatory subunit (RIIbeta) of protein kinase A are abnormally high in the nuclei of T cells of some subjects with the autoimmune disorder systemic lupus erythematosus (SLE). However, the role of nuclear RIIbeta in the regulation of T cell function is unknown. Based on previous studies demonstrating that nuclear protein kinase A-RII subunits can modify cAMP response element (CRE)-dependent transcription, we tested the hypothesis that nuclear RIIbeta can alter CRE-directed gene expression in T cells through interaction with the nuclear transcription factor CRE-binding protein CREB. To test this hypothesis, we used the RIIbeta-deficient S49 and the Jurkat T cell lines. In both cell lines, transient transfection of RIIbeta resulted in nuclear localization of a portion of the ectopically expressed RIIbeta. In vitro and in vivo analyses revealed a novel, specific interaction between RIIbeta and CREB that mapped to the N-terminal 135 aa of RIIbeta. In functional studies, RIIbeta inhibited the transcriptional activity of a GAL4-CREB fusion protein by 67% in Jurkat T cells following activation with anti-CD3 and anti-CD28 mAbs. Importantly, deletion of the CREB-binding region of RIIbeta completely abrogated inhibition. Additionally, RIIbeta suppressed CRE-directed reporter gene expression and substantially reduced induction of promoter activity and endogenous protein levels of the CREB-dependent gene, c-fos, in activated T cells. We conclude that nuclear RIIbeta can act as a repressor of CREB transcriptional activity in T cells, providing a potential functional significance for aberrant levels of nuclear RIIbeta in systemic lupus erythematosus T cells.
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Affiliation(s)
- Michael R Elliott
- Department of Microbiology and Immunology, Wake Forest University School of Medicine, Winston-Salem, NC 27157, USA
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Kotera J, Sasaki T, Kobayashi T, Fujishige K, Yamashita Y, Omori K. Subcellular localization of cyclic nucleotide phosphodiesterase type 10A variants, and alteration of the localization by cAMP-dependent protein kinase-dependent phosphorylation. J Biol Chem 2003; 279:4366-75. [PMID: 14604994 DOI: 10.1074/jbc.m308471200] [Citation(s) in RCA: 73] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Our previous studies have suggested that two phosphodiesterase type 10A (PDE10A) variants, PDE10A1 and PDE10A2 transcripts, are mainly expressed in humans and that PDE10A2 and PDE10A3 transcripts are major variants in rats. In the present study, immunoblot analysis demonstrated that PDE10A proteins, especially PDE10A2, are more abundant in membrane fractions than in cytosolic fractions of rat striatum. Recombinant PDE10A1 and PDE10A3 were produced only in cytosolic fractions of transfected PC12h cells. By contrast, recombinant PDE10A2 was present mainly in membrane fractions. This finding agreed well with the result of subcellular fractionation of PDE10A in rat striatum. Immunocytochemical analysis showed that PDE10A2 was localized in the Golgi apparatus of transfected PC12h cells. PDE10A2 was phosphorylated by cAMP-dependent protein kinase (PKA) at Thr16. Interestingly, recombinant protein of wild-type PDE10A2, but not PDE10A2 mutant with an Ala replacement at Thr16, was distributed to cytosolic fractions by co-transfection with a plasmid encoding the catalytic subunit of PKA. A PDE10A2 mutant with Glu substitution at Thr16, which can be a mimic of phosphorylation, was localized in the cytosolic fractions of transfected PC12h cells. These observations implied that phosphorylation of PDE10A2 at Thr16 by PKA caused alteration of subcellular localization of PDE10A2 from the Golgi apparatus to cytosol. It is hypothesized that cAMP signaling in the Golgi area and the cytosol in neurons is controlled through alteration of subcellular localization of PDE10A brought by activation of PKA in response to intracellular elevations of cAMP.
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Affiliation(s)
- Jun Kotera
- Discovery and Pharmacology Research Laboratories, Tanabe Seiyaku Co., Ltd., 2-50, Kawagishi-2-chome, Toda, Saitama 335-8505, Japan
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Vortherms TA, Watts VJ. Sensitization of neuronal A2A adenosine receptors after persistent D2 dopamine receptor activation. J Pharmacol Exp Ther 2003; 308:221-7. [PMID: 14566008 DOI: 10.1124/jpet.103.057083] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Acute activation of Galpha(i/o)-coupled D2 dopamine receptors inhibits A2A adenosine receptor stimulation of adenylate cyclase. This antagonistic interaction between D2 dopamine and A2A adenosine receptors has been well documented; however, the effects of persistent activation of D2 dopamine receptors on subsequent A2A adenosine receptor signaling have not been explored. The present study investigated the effects of short-term (3-h) and long-term (18-h) activation of D2L dopamine receptors on subsequent A2A adenosine receptor stimulation of adenylate cyclase in CAD-D2L and NS20Y-D2L neuroblastoma cells. Short- and long-term activation of D2L dopamine receptors markedly increased 5'-N-methylcarboxamidoadenosine (MECA)-stimulated cyclic AMP accumulation 1.4-fold and 1.7-fold, respectively. D2L receptor-induced sensitization of A2A-stimulated cyclic AMP accumulation was blocked by the D2 antagonist spiperone and pertussis toxin pretreatment. In addition, persistent activation of A2A adenosine receptors resulted in 50% desensitization of subsequent MECA-stimulated cyclic AMP accumulation; however, MECA-induced desensitization of A2A adenosine receptors did not prevent completely quinpirole-induced sensitization of adenylate cyclase. These studies revealed a novel mode of regulation between D2L dopamine and A2A adenosine receptors and suggest a cooperative interaction in the regulation of cyclic AMP signaling.
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Affiliation(s)
- Timothy A Vortherms
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, Indiana 47907, USA
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Hassan S, Duong B, Kim KS, Miles MF. Pharmacogenomic analysis of mechanisms mediating ethanol regulation of dopamine beta-hydroxylase. J Biol Chem 2003; 278:38860-9. [PMID: 12842874 DOI: 10.1074/jbc.m305040200] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
We previously showed that ethanol regulates dopamine beta-hydroxylase (DBH) mRNA and protein levels in human neuroblastoma cells (Thibault, C., Lai, C., Wilke, N., Duong, B., Olive, M. F., Rahman, S., Dong, H., Hodge, C. W., Lockhart, D. J., and Miles, M. F. (2000) Mol. Pharmacol. 58, 1593-1600). DBH catalyzes norepinephrine synthesis, and several studies have suggested a role for norepinephrine in ethanol-mediated behaviors. Here, we performed a detailed analysis of mechanism(s) underlying ethanol regulation of DBH expression in SH-SY5Y cells. Transient transfection analysis showed that ethanol (25-200 mM) caused concentration- and time-dependent increases in DBH gene transcription. Progressive deletions identified ethanol-responsive sequences in the -262 to -142 bp region of the DBH gene promoter. Mutagenesis of cAMP-response element (CRE) sequences in this region abolished ethanol responsiveness while maintaining responsiveness to phorbol esters. Coexpression of dominant-negative CRE-binding protein greatly reduced ethanol induction of DBH. Inhibitors of protein kinase A, casein kinase II, and MAPK reduced ethanol induction of DBH promoter activity. Pharmacogenomic studies with microarrays showed that protein kinase A, MEK, and casein kinase II inhibitors blocked induction of DBH and a large subset of ethanol-responsive genes. These genes had diverse functional groupings, including multiple members of the MAPK and phosphatidylinositol signaling cascades. Real-time PCR analysis validated select microarray results. Taken together, these results suggest that ethanol regulation of DBH requires a functional CRE and its binding protein and may require interaction of multiple kinase pathways. This mechanism may also mediate ethanol responsiveness of a complex subset of genes in neural cells. These studies may have implications for behavioral responses to ethanol or mechanisms underlying ethanol-related neurological disease.
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Affiliation(s)
- Sajida Hassan
- Departments of Pharmacology Toxicology and Neurology and the Center for Study of Biological Complexity, Virginia Commonwealth University, Richmond, Virginia 23298, USA
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Chandler LJ. Ethanol and brain plasticity: receptors and molecular networks of the postsynaptic density as targets of ethanol. Pharmacol Ther 2003; 99:311-26. [PMID: 12951163 DOI: 10.1016/s0163-7258(03)00096-2] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Brain plasticity refers to the ability of the brain to undergo structural and functional changes. It is a necessary process that allows us to adapt and learn from our environment and is fundamental to our survival. However, under certain conditions, these neuroadaptive responses can have adverse consequences. In particular, increasing evidence indicates that plastic processes are coopted by drugs of abuse, leading to addiction and associated drug-seeking behaviors. An extensive and diverse group of studies ranging from the molecular to the behavioral level has also strongly implicated glutamatergic neurotransmission as a critical mediator of experience-dependent synaptic plasticity. Thus, it is vital to understand how drugs of abuse interact and potentially alter glutamatergic neurotransmission and associated signal transduction processes. This review will focus on the cellular and molecular neuroscience of alcoholism, with emphasis on events at the glutamatergic postsynaptic density (PSD) and dendritic spine dynamics that appear to underlie much of the structural and functional plasticity of the CNS.
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Affiliation(s)
- L Judson Chandler
- Department of Physiology, Medical University of South Carolina, 67 President Street, Charleston, SC 29425-2508, USA.
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Ferrani-Kile K, Randall PK, Leslie SW. Acute ethanol affects phosphorylation state of the NMDA receptor complex: implication of tyrosine phosphatases and protein kinase A. BRAIN RESEARCH. MOLECULAR BRAIN RESEARCH 2003; 115:78-86. [PMID: 12824058 DOI: 10.1016/s0169-328x(03)00186-4] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Phosphorylation has been shown to regulate N-methyl-D-aspartic acid receptor (NMDAR) function. The inhibitory effect of ethanol on NMDAR function could be due, at least in part, to a change in NMDAR phosphorylation states. In order to investigate the effect of ethanol on phosphorylation of NR1 and NR2 subunits, NMDAR complexes were immunoprecipitated from cortical slices pre-exposed to ethanol. Acute ethanol, 100 and 200 mM, significantly decreased the tyrosine phosphorylation of NR2 subunits (Tyr-NR2). Treatment with a tyrosine phosphatase inhibitor reduced the inhibition of Tyr-NR2 phosphorylation caused by 100 mM ethanol. This suggests an involvement of tyrosine phosphatases in ethanol-induced inhibition of Tyr-NR2 phosphorylation. Slices pre-exposed to 100 and 200 mM ethanol exhibited a significant increase in the phosphorylation of NR1 by PKA at serine 897 (Ser897-NR1), which was blocked by a PKA inhibitor. Moreover, at 200 mM, ethanol produced a significant increase in PKA activity. Together, these results indicate that ethanol may increase Ser897-NR1 phosphorylation by activating PKA. However, ethanol did not affect phosphorylation of NR1 subunits by PKC at serine 896. We conclude that ethanol has the ability to modulate phosphorylation of both NR2 and NR1 subunits and these effects appear to implicate tyrosine phosphatases and PKA, respectively.
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Affiliation(s)
- K Ferrani-Kile
- Division of Pharmacology and Toxicology, College of Pharmacy and the Waggoner Center for Alcohol and Addiction Research, The University of Texas at Austin, 1 University Station, A1915, Austin, TX 78712, USA.
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45
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Zippin JH, Chen Y, Nahirney P, Kamenetsky M, Wuttke MS, Fischman DA, Levin LR, Buck J. Compartmentalization of bicarbonate-sensitive adenylyl cyclase in distinct signaling microdomains. FASEB J 2003; 17:82-4. [PMID: 12475901 DOI: 10.1096/fj.02-0598fje] [Citation(s) in RCA: 231] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Intracellular targets of the ubiquitous second messenger cAMP are located at great distances from the most widely studied source of cAMP, the G protein responsive transmembrane adenylyl cyclases. We previously identified an alternative source of cAMP in mammalian cells lacking transmembrane spanning domains, the "soluble" adenylyl cyclase (sAC). We now demonstrate that sAC is distributed in specific subcellular compartments: mitochondria, centrioles, mitotic spindles, mid-bodies, and nuclei, all of which contain cAMP targets. Distribution at these intracellular sites proves that adenylyl cyclases are in close proximity to all cAMP effectors, suggesting a model in which local concentrations of cAMP are regulated by individual adenylyl cyclases targeted to specific microdomains throughout the cell.
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Affiliation(s)
- Jonathan H Zippin
- Department of Pharmacology, Joan and Sanford I. Weill Medical College of Cornell University, New York, New York 10021, USA
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Chen X, Dai JC, Greenfield EM. Termination of immediate-early gene expression after stimulation by parathyroid hormone or isoproterenol. Am J Physiol Cell Physiol 2002; 283:C1432-40. [PMID: 12372804 DOI: 10.1152/ajpcell.00221.2002] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
cAMP/PKA signaling transiently stimulates mRNA expression of immediate-early genes, including IL-6 and c-fos. We confirmed that these mRNAs are transiently stimulated by parathyroid hormone (PTH) in ROS 17/2.8 osteoblastic cells. Consistent with the role for cAMP/PKA signaling in this response, PTH induces transient cAMP elevation, PKA activation, and cAMP-responsive element-binding protein (CREB) phosphorylation. Our goal was to determine whether termination of immediate-early gene expression is due to receptor desensitization or cAMP degradation. The approaches used were 1) inhibition of PTH receptor desensitization with G protein-coupled receptor kinase 2 (GRK2) antisense oligonucleotides or antisense plasmids, 2) sustained activation of adenyl cyclase with forskolin, and 3) inhibition of cAMP degradation with 3-isobutyl-1-methylxanthine. These experiments show that mechanisms downstream of receptor desensitization and cAMP degradation are primarily responsible for termination of PKA activity, CREB phosphorylation, and immediate-early gene expression. Similar conclusions were also obtained in response to PTH in a second osteoblastic cell line (MC3T3-E1) and in response to isoproterenol in NIH3T3 fibroblasts. This conclusion may therefore reflect a general mechanism for termination of immediate-early gene expression after induction by cAMP/PKA.
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Affiliation(s)
- Xin Chen
- Department of Orthopaedics, Case Western Reserve University and University Hospitals of Cleveland, Cleveland, Ohio 44106-5000, USA
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47
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Yao L, Arolfo MP, Dohrman DP, Jiang Z, Fan P, Fuchs S, Janak PH, Gordon AS, Diamond I. betagamma Dimers mediate synergy of dopamine D2 and adenosine A2 receptor-stimulated PKA signaling and regulate ethanol consumption. Cell 2002; 109:733-43. [PMID: 12086672 DOI: 10.1016/s0092-8674(02)00763-8] [Citation(s) in RCA: 111] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Dopamine release is activated by ethanol and addicting drugs, but molecular mechanisms linking dopaminergic signaling to neuronal responses and drinking behavior are poorly understood. We report that dopamine-D2 receptors induce PKA Calpha translocation and increase CRE-regulated gene expression. Ethanol also activates PKA signaling. Subthreshold concentrations of the D2 agonist NPA and ethanol, without effect alone, together cause synergistic PKA translocation and CRE-mediated gene transcription. D2 or adenosine A2 receptor blockade, pertussis toxin, Rp-cAMPS, or overexpression of dominant-negative peptides that sequester betagamma dimers prevent synergy. Importantly, overexpression of a betagamma inhibitor peptide in the nucleus accumbens strikingly reduces sustained alcohol consumption. We propose that synergy of D2 and A2 confers ethanol hypersensitivity and that betagamma dimers are required for voluntary drinking.
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MESH Headings
- Adenoviridae/genetics
- Alcohol Drinking
- Animals
- Animals, Newborn
- Apomorphine/analogs & derivatives
- Apomorphine/pharmacology
- Blotting, Western
- Cyclic AMP/metabolism
- Cyclic AMP-Dependent Protein Kinases/metabolism
- Dimerization
- Dopamine Agonists/pharmacology
- Dose-Response Relationship, Drug
- Ethanol/pharmacology
- G1 Phase
- Gene Expression Regulation
- Genes, Reporter
- Hippocampus/cytology
- Immunohistochemistry
- Integrases/metabolism
- Isoenzymes/metabolism
- Luciferases/metabolism
- Microscopy, Confocal
- Models, Biological
- Peptides/chemistry
- Pertussis Toxin
- Protein Binding
- Protein Kinase C/metabolism
- Protein Kinase C-alpha
- Protein Structure, Tertiary
- Protein Transport
- Rats
- Rats, Sprague-Dawley
- Receptors, Dopamine D2/chemistry
- Receptors, Dopamine D2/metabolism
- Receptors, Purinergic P1/chemistry
- Receptors, Purinergic P1/metabolism
- Signal Transduction
- Subcellular Fractions
- Time Factors
- Transcription, Genetic
- Transfection
- Viral Proteins/metabolism
- Virulence Factors, Bordetella/pharmacology
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Affiliation(s)
- Lina Yao
- Ernest Gallo Clinic and Research Center, San Francisco, CA 94110, USA
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48
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Constantinescu A, Gordon AS, Diamond I. cAMP-dependent protein kinase types I and II differentially regulate cAMP response element-mediated gene expression: implications for neuronal responses to ethanol. J Biol Chem 2002; 277:18810-6. [PMID: 11886856 DOI: 10.1074/jbc.m112107200] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
We have shown that ethanol induces translocation of cAMP-dependent protein kinase (PKA) to the nucleus, cAMP response element-binding protein (CREB) phosphorylation, and cAMP response element-mediated gene transcription in NG108-15 cells. However, little is known about which PKA types regulate this process. We show here that under basal conditions NG108-15 cells contain type I PKA (CbetaRIbeta) primarily in cytosol and type II PKA (CalphaRIIbeta) in the particulate and nuclear fractions. Antagonists of both type I and type II PKA inhibit forskolin- and ethanol-induced cAMP response element-mediated gene transcription. However, only the type II PKA antagonist inhibits forskolin-induced Calpha and ethanol-induced Calpha and RIIbeta translocation to the nucleus and CREB phosphorylation; the type I antagonist is without effect. Our data suggest that forskolin- and ethanol-induced CREB phosphorylation and gene activation are differentially mediated by the two types of PKA. We propose that type II PKA is translocated and activated in the nucleus and induces CREB phosphorylation that is necessary but not sufficient for gene transcription. By contrast, type I PKA is activated in the cytoplasm, turning on a downstream pathway that activates other transcription cofactors that interact with phosphorylated CREB to induce gene transcription.
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Affiliation(s)
- Anastasia Constantinescu
- Ernest Gallo Clinic and Research Center, Department of Neurology, University of California at San Francisco, Emeryville, California 94608, USA.
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Asher O, Cunningham TD, Yao L, Gordon AS, Diamond I. Ethanol stimulates cAMP-responsive element (CRE)-mediated transcription via CRE-binding protein and cAMP-dependent protein kinase. J Pharmacol Exp Ther 2002; 301:66-70. [PMID: 11907158 DOI: 10.1124/jpet.301.1.66] [Citation(s) in RCA: 64] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Alcoholism is characterized by tolerance, dependence, and unrestrained craving for alcohol. Adaptive responses, including changes in gene expression in neurons, are thought to account for some of these complex behavioral abnormalities. We have shown in the NG108-15 neuroblastoma x glioma hybrid cell line that ethanol increases cellular cAMP levels via activation of adenosine A(2) receptors, leading to phosphorylation of the cAMP response element-binding protein (CREB). However, phosphorylation of CREB is not sufficient to activate cAMP response element (CRE)-mediated gene expression. Here we investigate whether ethanol increases CRE-mediated gene expression via endogenous CREB using a CRE-regulated luciferase reporter construct, transfected into NG108-15 cells. We find increased luciferase activity as a function of time of exposure to ethanol. Coexpression of a dominant-negative CREB construct blocked ethanol-stimulated CRE-luciferase expression, further suggesting that CREB is required for this response. We also determined whether ethanol-induced increases in gene expression are mediated by ethanol-induced increases in extracellular adenosine. We found that CRE-mediated gene expression induced by ethanol occurs in two phases: an early phase (4 h), in which adenosine receptor blockade prevents ethanol-induced gene expression, and a later phase (14 h), which is not blocked by an adenosine receptor antagonist. In both phases, inhibition of cAMP-dependent protein kinase A (PKA) activity prevented ethanol-induced CRE-mediated luciferase expression. Our data suggest that ethanol induces cAMP-dependent gene expression regulated by CREB and PKA and that this signaling pathway may mediate some of the addictive behaviors underlying alcoholism.
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Affiliation(s)
- Orna Asher
- Ernest Gallo Clinic and Research Center and Department of Neurology, University of California, San Francisco, Emeryville, California 94608, USA
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50
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Ethanol-Induced Translocation of Protein Kinase A Occurs in Two Phases: Control by Different Molecular Mechanisms. Alcohol Clin Exp Res 2002. [DOI: 10.1097/00000374-200203000-00016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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