ABSTRACT
Methamphetamine (Meth) abuse can lead to the breakdown of the blood-brain barrier (BBB) integrity leading to compromised CNS function. The role of Galectins in the angiogenesis process in tumor-associated endothelial cells (EC) is well established; however no data are available on the expression of Galectins in normal human brain microvascular endothelial cells and their potential role in maintaining BBB integrity. We evaluated the basal gene/protein expression levels of Galectin-1, -3 and -9 in normal primary human brain microvascular endothelial cells (BMVEC) that constitute the BBB and examined whether Meth altered Galectin expression in these cells, and if Galectin-1 treatment impacted the integrity of an in-vitro BBB. Our results showed that BMVEC expressed significantly higher levels of Galectin-1 as compared to Galectin-3 and -9. Meth treatment increased Galectin-1 expression in BMVEC. Meth induced decrease in TJ proteins ZO-1, Claudin-3 and adhesion molecule ICAM-1 was reversed by Galectin-1. Our data suggests that Galectin-1 is involved in BBB remodeling and can increase levels of TJ proteins ZO-1 and Claudin-3 and adhesion molecule ICAM-1 which helps maintain BBB tightness thus playing a neuroprotective role. Galectin-1 is thus an important regulator of immune balance from neurodegeneration to neuroprotection, which makes it an important therapeutic agent/target in the treatment of drug addiction and other neurological conditions.
Subject(s)
Central Nervous System Stimulants/pharmacology , Endothelial Cells/drug effects , Galectin 1/pharmacology , Gene Expression Regulation/drug effects , Methamphetamine/pharmacology , Neuroprotective Agents/pharmacology , Brain/cytology , CREB-Binding Protein/metabolism , Capillary Permeability/drug effects , Cell Survival/drug effects , Cells, Cultured , Claudin-5/genetics , Claudin-5/metabolism , Cytokines/genetics , Cytokines/metabolism , Drug Interactions , Humans , Intercellular Adhesion Molecule-1/genetics , Intercellular Adhesion Molecule-1/metabolism , RNA, Messenger/metabolism , Reactive Oxygen Species/metabolism , Zonula Occludens-1 Protein/genetics , Zonula Occludens-1 Protein/metabolismABSTRACT
Opiates act on the dopaminergic system of the brain and perturb 32 kDa dopamine and adenosine 3', 5'-monophosphate-regulated phosphoprotein (DARPP-32) function. The DARPP-32 mediated inhibition of protein phosphatase-1 (PP-1) and modulation of transcriptional factor CREB is critical to the changes in neuronal plasticity that result in behavioral responses during drug abuse. To investigate the role of DARPP-32 mediated signaling on withdrawal behavior in a rat model of opiate addiction, we used intracerebral administration of gold nanorods (GNR) complexed to DARPP-32 siRNA to silence DARPP-32 gene expression and measure its effects on the opiate withdrawal syndrome. We hypothesized that DARPP-32 siRNA will suppress the neurochemical changes underlying the withdrawal syndrome and therefore prevent conditioned place aversion by suppressing or removing the constellation of negative effects associated with withdrawal, during the conditioning procedure. Our results showed that opiate addicted animals treated with GNR-DARPP-32 siRNA nanoplex showed lack of condition place aversive behavior consequent to the downregulation of secondary effectors such as PP-1 and CREB which modify transcriptional gene regulation and consequently neuronal plasticity. Thus, nanotechnology based delivery systems could allow sustained knockdown of DARPP-32 gene expression which could be developed into a therapeutic intervention for treating drug addiction by altering reward and motivational systems and interfere with conditioned responses.
