G protein-coupled receptor kinase 2 in multiple sclerosis and experimental autoimmune encephalomyelitis.
Many modulators of inflammation, including chemokines, neuropeptides, and neurotransmitters signal via G protein-coupled receptors (GPCR). GPCR kinases (GRK) can phosphorylate agonist-activated GPCR thereby promoting receptor desensitization. Here we describe that in leukocytes from patients with active relapsing-remitting multiple sclerosis (MS) or with secondary progressive MS, GRK2 levels are significantly reduced. Unexpectedly, cells from patients during remission express even lower levels of GRK2. The level of GRK2 in leukocytes of patients after stroke, a neurological disorder with paralysis but without an autoimmune component, was similar to GRK2 levels in cells from healthy individuals. In addition, we demonstrate that the course of recombinant myelin oligodendrocyte glycoprotein (1-125)-induced experimental autoimmune encephalomyelitis (EAE), an animal model for MS, is markedly different in GRK2(+/-) mice that express 50% of the GRK2 protein in comparison with wild-type mice. Onset of EAE was significantly advanced by 5 days in GRK2(+/-) mice. The earlier onset of EAE was associated with increased early infiltration of the CNS by T cells and macrophages. Although disease scores in the first phase of EAE were similar in both groups, GRK2(+/-) animals did not develop relapses, whereas wild-type animals did. The absence of relapses in GRK2(+/-) mice was associated with a marked reduction in inflammatory infiltrates in the CNS. Recombinant myelin oligodendrocyte glycoprotein-induced T cell proliferation and cytokine production were normal in GRK2(+/-) animals. We conclude that down-regulation of GRK2 expression may have important consequences for the onset and progression of MS.
Vroon
Anne
A
Laboratory for Psychoneuroimmunology, University Medical Center Utrecht, Utrecht, The Netherlands.
Kavelaars
Annemieke
A
Limmroth
Volker
V
Lombardi
Maria Stella
MS
Goebel
Marion U
MU
Van Dam
Anne-Marie
AM
Caron
Marc G
MG
Schedlowski
Manfred
M
Heijnen
Cobi J
CJ
D000818:Animals; D016022:Case-Control Studies; D002465:Cell Movement / Q000276:immunology; D002490:Central Nervous System / Q000276:immunology / Q000473:pathology; D017868:Cyclic AMP-Dependent Protein Kinases / Q000172:deficiency* / Q000502:physiology; D004681:Encephalomyelitis, Autoimmune, Experimental / Q000201:enzymology* / Q000209:etiology / Q000276:immunology; D005260:Female; D054769:G-Protein-Coupled Receptor Kinase 2; D054770:G-Protein-Coupled Receptor Kinase 3; D006801:Humans; D007249:Inflammation / Q000276:immunology; D007962:Leukocytes / Q000201:enzymology / Q000276:immunology; D008264:Macrophages / Q000276:immunology; D008297:Male; D051379:Mice; D018345:Mice, Knockout; D009103:Multiple Sclerosis / Q000201:enzymology* / Q000209:etiology / Q000276:immunology; D043562:Receptors, G-Protein-Coupled / Q000172:deficiency* / Q000502:physiology; D012008:Recurrence; D013601:T-Lymphocytes / Q000276:immunology; D051552:beta-Adrenergic Receptor Kinases
D043562:Receptors, G-Protein-Coupled; D017868:Cyclic AMP-Dependent Protein Kinases; D054770:G-Protein-Coupled Receptor Kinase 3; C496567:GRK2 protein, human; C517848:GRK3 protein, human; C517850:GRK3 protein, mouse; D051552:beta-Adrenergic Receptor Kinases; D054769:G-Protein-Coupled Receptor Kinase 2