title: Therapeutic targeting of "DARPP-32": a key signaling molecule in the dopiminergic pathway for the treatment of opiate addiction.
abstract: The 32-kDa dopamine- and adenosine 3',5'-monophosphate-regulated phosphoprotein (DARPP-32) is recognized to be critical to the pathogenesis of drug addiction. Opiates via the mu-receptor act on the dopaminergic system in the brain and modulates the expression of DARPP-32 phosphoprotein which is an important mediator of the activity of the extracellular signal-regulated kinase (ERK) signaling cascades, the activation of which represents an exciting nexus for drug-induced changes in neural long-term synaptic plasticity. Silencing of DARPP-32 using an siRNA against DARPP-32 may provide a novel gene therapy strategy to overcome drug addiction. In this study, we investigated the effect of the opiate (heroin) on D1 receptor (D1R) and DARPP-32 expression and additionally, evaluated the effects of DARPP-32-siRNA gene silencing on protein phosphatase-1 (PP-1), ERK, and cAMP response element-binding (CREB) gene expression in primary normal human astrocytes (NHA) cells in vitro. Our results indicate that heroin significantly upregulated both D1R and DARPP-32 gene expression, and that DARPP-32 silencing in the NHA cells resulted in the significant modulation of the activity of downstream effector molecules such as PP-1, ERK, and CREB which are known to play an important role in opiate abuse-induced changes in long-term neural plasticity. These findings have the potential to facilitate the development of DARPP32 siRNA-based therapeutics against drug addiction.
authors.affiliation: Department of Medicine, Division of Allergy, Immunology, and Rheumatology, Buffalo General Hospital, State University of New York, Buffalo, New York 14203, USA.
authors.forename: Supriya D
authors.initials: SD
authors.lastname: Mahajan
authors.forename: Ravikumar
authors.initials: R
authors.lastname: Aalinkeel
authors.forename: Jessica L
authors.initials: JL
authors.lastname: Reynolds
authors.forename: Bindukumar B
authors.initials: BB
authors.lastname: Nair
authors.forename: Donald E
authors.initials: DE
authors.lastname: Sykes
authors.forename: Zihua
authors.initials: Z
authors.lastname: Hu
authors.forename: Adela
authors.initials: A
authors.lastname: Bonoiu
authors.forename: Hong
authors.initials: H
authors.lastname: Ding
authors.forename: Paras N
authors.initials: PN
authors.lastname: Prasad
authors.forename: Stanley A
authors.initials: SA
authors.lastname: Schwartz
mesh_terms: D002478:Cells, Cultured; D051937:Dopamine and cAMP-Regulated Phosphoprotein 32 / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism; D048049:Extracellular Signal-Regulated MAP Kinases / Q000187:drug effects / Q000378:metabolism; D015870:Gene Expression / Q000187:drug effects; D003932:Heroin / Q000494:pharmacology*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D009294:Narcotics / Q000494:pharmacology*; D020411:Oligonucleotide Array Sequence Analysis; D009293:Opioid-Related Disorders / Q000235:genetics / Q000378:metabolism*; D034741:RNA, Small Interfering; D017447:Receptors, Dopamine D1 / Q000096:biosynthesis / Q000187:drug effects; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014162:Transfection
chemical_list: D051937:Dopamine and cAMP-Regulated Phosphoprotein 32; D009294:Narcotics; D034741:RNA, Small Interfering; D017447:Receptors, Dopamine D1; D003932:Heroin; D048049:Extracellular Signal-Regulated MAP Kinases