Deciphering the immune function and regulation by a TLR of the cytokine EMAPII in the lesioned central nervous system using a leech model.
A highly conserved ortholog of the human complex p43/endothelial monocyte-activating polypeptide II (EMAPII) was characterized in the CNS of the leech Hirudo medicinalis. As observed in mammals, the leech complex is processed to release the cytokine HmEMAPII. Taking advantages of these similarities, we have attempted to elucidate the role of EMAPII in the CNS using the leech model. Although EMAPII is considered a modulator of inflammatory reactions within the peripheral innate immune response in humans, its function in CNS immunity has yet to be described. Chemotaxis assays were conducted, revealing the ability of EMAPII to exert a chemoattractant effect on both leech and human microglial cells, indicating a novel function of this cytokine in the human brain. Quantitative RT-PCR analysis together with in situ hybridization and immunohistochemistry approaches showed that bacterial challenge induced the expression of HmEMAPII at the lesion site where microglial cells accumulated. Moreover, gene silencing experiments have demonstrated that the gene expression of HmEMAPII is under the control of a signaling pathway associated with the TLR HmTLR1, newly characterized in the CNS of our model. To the best of our knowledge, this is the first report showing evidence for (1) the chemoattractant properties of EMAPII on leech and human microglial cells, (2) the regulation by a TLR of the expression of a gene encoding a cytokine in the CNS of an invertebrate, and (3) an immune function of a TLR in a lophotrochozoan model.
Schikorski
David
D
Laboratoire de Neuroimmunologie des Annélides, FRE Centre National de la Recherche Scientifique 2933, Groupe Signaux de Danger, Voies de Signalisation et Effecteurs, Université de Lille 1, 59655 Villeneuve d'Ascq, France.
Cuvillier-Hot
Virginie
V
Boidin-Wichlacz
Céline
C
Slomianny
Christian
C
Salzet
Michel
M
Tasiemski
Aurélie
A
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D015153:Blotting, Western; D002490:Central Nervous System / Q000276:immunology*; D002633:Chemotaxis; D016207:Cytokines / Q000235:genetics / Q000276:immunology* / Q000378:metabolism; D015870:Gene Expression; D005786:Gene Expression Regulation / Q000276:immunology*; D047709:Hirudo medicinalis / Q000276:immunology; D006801:Humans; D007150:Immunohistochemistry; D017404:In Situ Hybridization, Fluorescence; D007865:Leeches / Q000276:immunology*; D017628:Microglia / Q000378:metabolism; D008969:Molecular Sequence Data; D009363:Neoplasm Proteins / Q000235:genetics / Q000276:immunology* / Q000378:metabolism; D010802:Phylogeny; D034622:RNA Interference; D016601:RNA-Binding Proteins / Q000235:genetics / Q000276:immunology* / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D020539:Sequence Analysis, Protein; D015398:Signal Transduction / Q000235:genetics; D051193:Toll-Like Receptors / Q000276:immunology*
D016207:Cytokines; D009363:Neoplasm Proteins; D016601:RNA-Binding Proteins; D051193:Toll-Like Receptors; C077219:small inducible cytokine subfamily E, member 1