Involvement of the neurotensin receptor-3 in the neurotensin-induced migration of human microglia.
Microglia motility plays a crucial role in response to lesion or exocytotoxic damage of the cerebral tissue. We used two in vitro assays, a wound-healing model and a chemotaxis assay, to show that the neuropeptide neurotensin elicited the migration of the human microglial cell line C13NJ by a mechanism dependent on both phosphatidylinositol 3-kinase (PI 3-kinase) and mitogen-activated protein (MAP) kinase pathways. The effect of neurotensin on cell migration was blocked by the neurotensin receptor-3 propeptide, a selective ligand of this receptor. We demonstrate, by using RT-PCR, photoaffinity labeling, and Western blot analysis, that the type I neurotensin receptor-3 was the only known neurotensin receptor expressed in these microglial cells and that its activation led to the phosphorylation of both extracellular signal-regulating kinases 1/2 and Akt. Furthermore, the effect of neurotensin on cell migration was preceded by a profound modification of the F-actin cytoskeleton, particularly by the rapid formation of numerous cell filopodia. Both the motility and the filopodia appearance induced by neurotensin were totally blocked by selective inhibitors of MAP kinases or PI 3-kinase pathways. This demonstrates that the neurotensin receptor-3 is functional and mediates the migratory actions of neurotensin.
Martin
Stephane
S
Institut de Pharmacologie Moléculaire et Cellulaire, Unité Mixte de Recherche 6097 du Centre National de la Recherche Scientifique, Sophia Antipolis, 06560 Valbonne, France.
Vincent
Jean-Pierre
JP
Mazella
Jean
J
D008841:Actin Cytoskeleton / Q000187:drug effects / Q000648:ultrastructure; D033942:Adaptor Proteins, Vesicular Transport; D002460:Cell Line; D002465:Cell Movement; D006801:Humans; D008562:Membrane Glycoproteins / Q000235:genetics / Q000502:physiology*; D017628:Microglia / Q000187:drug effects / Q000502:physiology*; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000502:physiology*; D009496:Neurotensin / Q000494:pharmacology*; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D012333:RNA, Messenger / Q000096:biosynthesis; D015398:Signal Transduction; D000099183:Sortilin
D033942:Adaptor Proteins, Vesicular Transport; D008562:Membrane Glycoproteins; D020928:Mitogen-Activated Protein Kinases; D009419:Nerve Tissue Proteins; D009496:Neurotensin; D019869:Phosphatidylinositol 3-Kinases; D012333:RNA, Messenger; D000099183:Sortilin