Cocaine promotes primary human astrocyte proliferation via JNK-dependent up-regulation of cyclin A2.
Astrocytes perform a plethora of important functions in the central nervous system (CNS) and are involved in cocaine-evoked synaptic plasticity. Previously, we showed that while cocaine decreased cyclin A2 expression in primary human neural progenitor cells, it increased cyclin A2 expression in human astrocytes. Since cyclin A2 is an essential regulator of the cell cycle, the aim of the present study is to clarify the effect of cocaine on proliferation of human astrocytes and elucidate the underlying molecular mechanisms.



Primary human astrocytes were treated with either 1, 10, or 100 μM cocaine for 48 hr, and cell proliferation was measured using the CyQUANT cell proliferation assay. To elucidate the molecular mechanisms through which cocaine affects the proliferation of astrocytes, we analyzed gene expression profiles in cocaine-treated primary human astrocytes using a human focused cDNA array. Gene ontology/pathway enrichment analysis, STRING protein-protein interaction analysis, RT-qPCR, and western blotting were used to identify signal transduction pathways that are involved in cocaine-induced astrocyte dysfunction.



Cocaine at 10 and 100 μM significantly increased human astrocyte proliferation. Gene expression profiling revealed the JNK MAP kinase pathway as a driver of cell proliferation affected by cocaine in human astrocytes. Further experiments showed that cocaine-induced JNK activation induced up-regulation of cyclin A2, leading to enhanced proliferation of human astrocytes.



Cocaine-induced abnormal increases in the number of astrocytes may cause disruption in neuron-glia signaling and contribute to synaptic impairment in the CNS. Understanding the mechanisms of cocaine's effects on human astrocytes may help to reveal the involvement of glial cells in addictive behaviors.
Section on Development and Plasticity, Cellular Neurobiology Research Branch, Intramural Research Program (IRP), National Institute on Drug Abuse, National Institutes of Health (NIH), Baltimore, MD, USA.|Department of Neurology, Miller School of Medicine, University of Miami, Miami, FL, USA.
Chun-Ting
CT
Lee
Department of Biology, Lebanon Valley College, Annville, PA, USA.
Kristen L
KL
Boeshore
Department of Molecular and Cellular Pharmacology, Miller School of Medicine, University of Miami, Miami, FL, USA.
Chun
C
Wu
Gene Expression and Genomics Unit, Research Resources Branch, IRP, National Institute on Aging, NIH, Baltimore, MD, USA.
Kevin G
KG
Becker
Section on Development and Plasticity, Cellular Neurobiology Research Branch, Intramural Research Program (IRP), National Institute on Drug Abuse, National Institutes of Health (NIH), Baltimore, MD, USA.
Stacie L
SL
Errico
Department of Neurology, Miller School of Medicine, University of Miami, Miami, FL, USA.|Department of Molecular and Cellular Pharmacology, Miller School of Medicine, University of Miami, Miami, FL, USA.
Deborah C
DC
Mash
Section on Development and Plasticity, Cellular Neurobiology Research Branch, Intramural Research Program (IRP), National Institute on Drug Abuse, National Institutes of Health (NIH), Baltimore, MD, USA.|Department of Biology, Lebanon Valley College, Annville, PA, USA.
William J
WJ
Freed
D000704:Analysis of Variance; D000779:Anesthetics, Local / Q000494:pharmacology*; D001253:Astrocytes / Q000187:drug effects*; D049109:Cell Proliferation / Q000187:drug effects*; D003042:Cocaine / Q000494:pharmacology*; D056751:Cyclin A2 / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D020869:Gene Expression Profiling; D005904:Glial Fibrillary Acidic Protein / Q000378:metabolism; D006801:Humans; D048670:MAP Kinase Kinase 4 / Q000378:metabolism*; D020411:Oligonucleotide Array Sequence Analysis; D012333:RNA, Messenger; D015398:Signal Transduction / Q000187:drug effects; D015854:Up-Regulation / Q000187:drug effects*
D000779:Anesthetics, Local; D056751:Cyclin A2; D005904:Glial Fibrillary Acidic Protein; D012333:RNA, Messenger; D048670:MAP Kinase Kinase 4; D003042:Cocaine
Astrocytes; JNK; addiction; cocaine; cyclin A; reactive astrogliosis