5-aminoimidazole-4-carboxamide-1-beta-4-ribofuranoside attenuates experimental autoimmune encephalomyelitis via modulation of endothelial-monocyte interaction.
Experimental autoimmune encephalomyelitis (EAE) is a model for studying multiple sclerosis (MS), a chronic demyelinating disorder of the CNS. 5-Aminoimidazole-4-carboxamide ribonucleoside (AICAR), an activator of AMP-activated protein kinase (AMPK), has been reported to show antiinflammatory and immunomodulatory effects in various models of inflammation. Recently, we have reported AICAR-mediated attenuation of active and passive EAE in mouse model [Nath et al. (2005) J. Immunol. 175:566-574]. Here we used a rat model of acute EAE to show antiinflammatory effects of AICAR after daily treatment starting at onset of the disease. By maintaining the blood-brain barrier (BBB), AICAR-administered animals showed lower clinical scores compared with untreated EAE animals. AICAR inhibited the infiltration of inflammatory cells across the BBB, resulting in lowered expression of proinflammatory mediators in the CNS and protection from severe demyelination. By using in vitro model of endothelial-leukocyte interaction, we showed that AICAR inhibited adhesion of monocytes to tumor necrosis factor-alpha-activated endothelial cells. One of the mechanisms of this action is through down-regulation of expression of endothelial cell adhesion molecules via modulation of nuclear factor kappaB activation. The data suggest that AICAR attenuates EAE progression by limiting infiltration of leukocytes across the BBB, thereby controlling the consequent inflammatory reaction in the CNS.
Prasad
Ratna
R
Department of Pediatrics, Medical University of South Carolina, Charleston, South Carolina 29425, USA.
Giri
Shailendra
S
Nath
Narender
N
Singh
Inderjit
I
Singh
Avtar K
AK
D000620:Aminoimidazole Carboxamide / Q000031:analogs & derivatives* / Q000494:pharmacology / Q000627:therapeutic use; D000818:Animals; D000893:Anti-Inflammatory Agents / Q000494:pharmacology / Q000627:therapeutic use; D001812:Blood-Brain Barrier / Q000187:drug effects* / Q000276:immunology / Q000378:metabolism; D002448:Cell Adhesion / Q000187:drug effects / Q000276:immunology; D015815:Cell Adhesion Molecules / Q000187:drug effects / Q000276:immunology; D002634:Chemotaxis, Leukocyte / Q000187:drug effects* / Q000276:immunology; D004195:Disease Models, Animal; D015536:Down-Regulation / Q000187:drug effects / Q000276:immunology; D004681:Encephalomyelitis, Autoimmune, Experimental / Q000188:drug therapy* / Q000276:immunology / Q000503:physiopathology; D042783:Endothelial Cells / Q000187:drug effects* / Q000378:metabolism; D005260:Female; D018836:Inflammation Mediators / Q000276:immunology / Q000378:metabolism; D051379:Mice; D009000:Monocytes / Q000187:drug effects* / Q000378:metabolism; D016328:NF-kappa B / Q000276:immunology / Q000378:metabolism; D051381:Rats; D011917:Rats, Inbred Lew; D012265:Ribonucleotides / Q000494:pharmacology* / Q000627:therapeutic use; D014409:Tumor Necrosis Factor-alpha / Q000276:immunology / Q000378:metabolism
D000893:Anti-Inflammatory Agents; D015815:Cell Adhesion Molecules; D018836:Inflammation Mediators; D016328:NF-kappa B; D012265:Ribonucleotides; D014409:Tumor Necrosis Factor-alpha; D000620:Aminoimidazole Carboxamide; C031143:AICA ribonucleotide