P2x7 deficiency suppresses development of experimental autoimmune encephalomyelitis.
BACKGROUND
The purinergic receptor P2x7 is expressed on myeloid cells as well as on CNS glial cells, and P2x7 activation has been shown to increase both glial and T-cell activation. These properties suggest a role in the development of autoimmune disease including multiple sclerosis.


METHODS
The animal model of MS, experimental autoimmune encephalomyelitis (EAE) using myelin oligodendrocyte glycoprotein (MOG) peptide residues 35-55 was induced in wildtype C57BL6 mice and in P2x7 deficient mice ('P2x7 mice') that were backcrossed to C57BL6 mice. Disease progression was monitored by appearance of clinical signs, immunocytochemical staining to assess brain inflammation and neuronal damage, and by measurement of Tcell cytokine production.


RESULTS
The incidence of EAE disease in P2x7 mice was reduced 4-fold compared to the wildtype mice; however the P2x7 mice that became ill had similar days of onset and clinical scores as the wildtype mice. Splenic T-cells isolated from P2x7 null mice produced greater IFNgamma and IL-17 (from 3 to 12 fold greater levels) than wildtype cells, however cytokine production from P2x7 derived cells was not increased by a selective P2x7 agonist as was cytokine production from wildtype cells. Although infiltrating cells were detected in brains of both the P2x7 and wildtype mice, astroglial activation and axonal damage was reduced versus wildtype mice, and the distribution of astroglial activation was markedly distinct in the two strains. In contrast, microglial activation was similar in the two strains.


CONCLUSIONS
P2x7 deficiency resulted in compensatory changes leading to increased T-cell cytokine production, and activated T-cells were detected in the brains of P2x7 null mice with no clinical signs. However, the greatly reduced incidence of disease suggests that an initiating event is absent in these mice, and points to a role for astroglial P2x7 in development of EAE disease.
Sharp
Anthony J
AJ
Department of Anesthesiology, University of Illinois, Chicago, IL 60612, USA. ajms@uic.edu
Polak
Paul E
PE
Simonini
Vittoria
V
Lin
Shao X
SX
Richardson
Jill C
JC
Bongarzone
Ernesto R
ER
Feinstein
Douglas L
DL
D000818:Animals; D001369:Axons / Q000378:metabolism / Q000473:pathology; D001921:Brain / Q000473:pathology; D016207:Cytokines / Q000276:immunology; D018450:Disease Progression; D004681:Encephalomyelitis, Autoimmune, Experimental / Q000276:immunology* / Q000473:pathology / Q000517:prevention & control*; D005260:Female; D006023:Glycoproteins / Q000276:immunology; D008213:Lymphocyte Activation; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D017628:Microglia / Q000166:cytology / Q000378:metabolism; D063308:Myelin-Oligodendrocyte Glycoprotein; D010446:Peptide Fragments / Q000276:immunology; D018048:Receptors, Purinergic P2 / Q000172:deficiency* / Q000235:genetics; D058486:Receptors, Purinergic P2X7; D013154:Spleen / Q000166:cytology / Q000276:immunology; D013601:T-Lymphocytes / Q000276:immunology
D016207:Cytokines; D006023:Glycoproteins; D063308:Myelin-Oligodendrocyte Glycoprotein; C546469:P2rx7 protein, mouse; D010446:Peptide Fragments; D018048:Receptors, Purinergic P2; D058486:Receptors, Purinergic P2X7; C445081:myelin oligodendrocyte glycoprotein (35-55)