Cultured rat microglial cells synthesize the endocannabinoid 2-arachidonylglycerol, which increases proliferation via a CB2 receptor-dependent mechanism. Mol Pharmacol 2004 Apr;65(4):999-1007
Date
03/27/2004Pubmed ID
15044630DOI
10.1124/mol.65.4.999Scopus ID
2-s2.0-1842428537 (requires institutional sign-in at Scopus site) 311 CitationsAbstract
Microglia, as phagocytes and antigen-presenting cells in the central nervous system, are activated in such disease processes as stroke and multiple sclerosis. Because peripheral macrophages are capable of producing endocannabinoids, we have examined endocannabinoid production in a macrophage-colony stimulating factor (M-CSF)-dependent rat microglial cell line (RTMGL1) using reversed phase high-pressure liquid chromatography and liquid chromatography-mass spectroscopy. We determined that cultured microglial cells produce the endocannabinoid 2-arachidonylglycerol (2-AG) as well as anandamide in smaller quantities. When 2-AG, but not anandamide, is added exogenously, RTMGL1 microglia increase their proliferation. This increased proliferation is blocked by an antagonist of the CB(2) receptor N-[(1S)endo-1,3,3-trimethyl bicyclo heptan-2-yl]-5-(4-chloro-3-methylphenyl)-1-(4-methylbenzyl)-pyrazole-3-carboxamide (SR144528) and mimicked by the CB(2) receptor-specific agonist 1,1-dimethylbutyl-1-deoxy-Delta(9)-tetrahydrocannabinol (JWH133). Accompanying the increase in proliferation seen with 2-AG is an increase in active ERK1 that is also blocked with SR144528. The RTMGL1 microglial cells, which exist in a primed state, express the CB(1) and CB(2) receptors as demonstrated by reverse transcription-polymerase chain reaction and immunostaining. The CB(2) receptor in untreated cells is expressed both at the cell surface and internally, and exposure of the cells to 2-AG significantly increases receptor internalization. These data suggest that 2-AG activation of CB(2) receptors may contribute to the proliferative response of microglial cells, as occurs in neurodegenerative disorders.
Author List
Carrier EJ, Kearn CS, Barkmeier AJ, Breese NM, Yang W, Nithipatikom K, Pfister SL, Campbell WB, Hillard CJAuthors
William B. Campbell PhD Professor in the Pharmacology and Toxicology department at Medical College of WisconsinCecilia J. Hillard PhD Associate Dean, Center Director, Professor in the Pharmacology and Toxicology department at Medical College of Wisconsin
Sandra L. Pfister PhD Professor in the Pharmacology and Toxicology department at Medical College of Wisconsin
MESH terms used to index this publication - Major topics in bold
Analysis of VarianceAnimals
Arachidonic Acids
Cannabinoid Receptor Modulators
Cell Division
Cells, Cultured
Endocannabinoids
Enzyme Activation
Flow Cytometry
Glycerides
Macrophage Colony-Stimulating Factor
Microglia
Mitogen-Activated Protein Kinases
Rats
Receptor, Cannabinoid, CB2