Microbial challenge promotes the regenerative process of the injured central nervous system of the medicinal leech by inducing the synthesis of antimicrobial peptides in neurons and microglia.
Following trauma, the CNS of the medicinal leech, unlike the mammalian CNS, has a strong capacity to regenerate neurites and synaptic connections that restore normal function. In this study, we show that this regenerative process is enhanced by a controlled bacterial infection, suggesting that induction of regeneration of normal CNS function may depend critically upon the coinitiation of an immune response. We explore the interaction between the activation of a neuroimmune response and the process of regeneration by assaying the potential roles of two newly characterized antimicrobial peptides. Our data provide evidence that microbial components differentially induce the transcription, by microglial cells, of both antimicrobial peptide genes, the products of which accumulate rapidly at sites in the CNS undergoing regeneration following axotomy. Using a preparation of leech CNS depleted of microglial cells, we also demonstrate the production of antimicrobial peptides by neurons. Interestingly, in addition to exerting antibacterial properties, both peptides act as promoters of the regenerative process of axotomized leech CNS. These data are the first to report the neuronal synthesis of antimicrobial peptides and their participation in the immune response and the regeneration of the CNS. Thus, the leech CNS appears as an excellent model for studying the implication of immune molecules in neural repair.
Schikorski
David
D
Centre National de la Recherche Scientifique FRE2933, Laboratoire de Neuroimmunologie des Annélides, Université de Lille 1, Villeneuve d'Ascq, France.
Cuvillier-Hot
Virginie
V
Leippe
Matthias
M
Boidin-Wichlacz
Céline
C
Slomianny
Christian
C
Macagno
Eduardo
E
Salzet
Michel
M
Tasiemski
Aurélie
A
D000333:Aeromonas / Q000276:immunology*; D000595:Amino Acid Sequence; D000818:Animals; D000942:Antigens, Bacterial / Q000276:immunology / Q000378:metabolism; D023181:Antimicrobial Cationic Peptides / Q000096:biosynthesis* / Q000737:chemistry / Q000235:genetics / Q000276:immunology; D019771:Axotomy; D001483:Base Sequence; D002490:Central Nervous System / Q000166:cytology / Q000276:immunology / Q000378:metabolism / Q000502:physiology; D005089:Exocytosis; D006094:Gram-Positive Bacteria / Q000276:immunology*; D047709:Hirudo medicinalis / Q000235:genetics / Q000276:immunology / Q000382:microbiology / Q000502:physiology*; D017628:Microglia / Q000166:cytology / Q000276:immunology / Q000378:metabolism*; D008969:Molecular Sequence Data; D009416:Nerve Regeneration; D009474:Neurons / Q000166:cytology / Q000276:immunology / Q000378:metabolism*; D016415:Sequence Alignment
D000942:Antigens, Bacterial; D023181:Antimicrobial Cationic Peptides