Production and neuroprotective functions of fractalkine in the central nervous system.
The CX3C-chemokine, fractalkine is reportedly to be expressed in the central nervous system, and up-regulated in certain pathological conditions, such as HIV encephalopathy and multiple sclerosis. In the present study, we examined the production of fractalkine and the expression of its receptor, CX3CR1 in murine glial and neuronal cell in vitro, and investigated its neuroprotective functions. Both fractalkine and CX3CR1 were expressed constitutively in neurons, microglia, and astrocytes. Neither the production of fractalkine nor its receptor expression was up-regulated by lipopolysaccharide (LPS), as measured by mRNA expression and protein synthesis. Fractalkine dose-dependently suppressed the production of nitric oxide (NO), interleukin (IL)-6 and tumor necrosis factor (TNF)-alpha with activated microglia. It also significantly suppressed neuronal cell death induced by microglia activated with LPS and interferon-gamma, in a dose-dependent manner. These results suggest the possible functions of fractalkine as an intrinsic inhibitor against neurotoxicity by activated microglia.
Mizuno
Tetsuya
T
Department of Neuroimmunology, Institute of Environmental Medicine, Nagoya University, Furo-cho, Chikusa, 464-8601, Nagoya, Japan. tmizuno@riem.nagoya-u.ac.jp
Kawanokuchi
Jun
J
Numata
Kenji
K
Suzumura
Akio
A
D000818:Animals; D001253:Astrocytes / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D000073883:CX3C Chemokine Receptor 1; D016923:Cell Death / Q000502:physiology; D002478:Cells, Cultured; D002540:Cerebral Cortex / Q000378:metabolism; D054428:Chemokine CX3CL1; D020523:Chemokines, CX3C / Q000096:biosynthesis*; D004305:Dose-Response Relationship, Drug; D004797:Enzyme-Linked Immunosorbent Assay; D015850:Interleukin-6 / Q000378:metabolism; D008070:Lipopolysaccharides / Q000494:pharmacology; D008565:Membrane Proteins / Q000096:biosynthesis* / Q000187:drug effects; D051379:Mice; D017628:Microglia / Q000187:drug effects / Q000378:metabolism* / Q000473:pathology; D009474:Neurons / Q000187:drug effects / Q000378:metabolism* / Q000473:pathology; D018696:Neuroprotective Agents / Q000378:metabolism; D009569:Nitric Oxide / Q000378:metabolism; D012333:RNA, Messenger / Q000032:analysis; D019707:Receptors, Chemokine / Q000096:biosynthesis*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism; D015854:Up-Regulation
D000073883:CX3C Chemokine Receptor 1; D054428:Chemokine CX3CL1; D020523:Chemokines, CX3C; C515539:Cx3cl1 protein, mouse; C471885:Cx3cr1 protein, mouse; D015850:Interleukin-6; D008070:Lipopolysaccharides; D008565:Membrane Proteins; D018696:Neuroprotective Agents; D012333:RNA, Messenger; D019707:Receptors, Chemokine; D014409:Tumor Necrosis Factor-alpha; D009569:Nitric Oxide