In vitro and in vivo effects of the probiotic Escherichia coli strain M-17: immunomodulation and attenuation of murine colitis.
We examined the in vitro and in vivo effects of a probiotic, Escherichia coli strain M-17 (EC-M17), on NF-kappaB signalling, cytokine secretion and efficacy in dextran sulfate sodium (DSS)-induced murine colitis. NF-kappaB signalling was assessed using an NF-kappaB luciferase reporter cell line that was stimulated with TNF-alpha (100 ng/ml). p65 Nuclear binding and cytokine secretion (TNF-alpha, IL-1beta and IL-6) were evaluated using a RAW 264.7 macrophage cell line that was exposed to lipopolysaccharide (LPS; 5 microg/ml). Mice were administered vehicle, EC-M17, metronidazole, or EC-M17 plus metronidazole for 13 d. During the final 6 d, mice also received 2 % DSS. Parameters evaluated included disease activity index (DAI), histology, myeloperoxidase and NF-kappaB p65. EC-M17 dose dependently inhibited TNF-alpha-induced NF-kappaB signalling. At 5 x 109 colony-forming units/ml, EC-M17 inhibited NF-kappaB by >95 %. LPS-induced nuclear p65 binding was significantly inhibited (78 %; P 90 %) the LPS-induced secretion of TNF-alpha, IL-1beta and IL-6. In mice with DSS-induced colitis, EC-M17, metronidazole, and EC-M17 plus metronidazole significantly reduced DAI and colonic histology scores. Both EC-M17 and metronidazole reduced colonic IL-12, IL-6, IL-1beta and interferon-gamma. The combination of EC-M17 plus metronidazole resulted in more substantial cytokine reductions than were found with either treatment alone, and combination therapy significantly (P < 0.05 in both cases) reduced IL-1beta compared with EC-M17 and colonic histology scores compared with metronidazole. Alone, and in combination with metronidazole, EC-M17 improved murine colitis, probably due to an inhibitory effect on NF-kappaB signalling.
Fitzpatrick
Leo R
LR
Department of Pharmacology, Penn State College of Medicine, 1214 Research Boulevard, Hummelstown, PA 17036, USA.
Small
Jeffrey
J
Hoerr
Robert A
RA
Bostwick
Eileen F
EF
Maines
Lynn
L
Koltun
Walter A
WA
D000818:Animals; D000890:Anti-Infective Agents / Q000627:therapeutic use; D002460:Cell Line; D003092:Colitis / Q000276:immunology* / Q000382:microbiology; D003106:Colon / Q000276:immunology* / Q000378:metabolism / Q000382:microbiology; D004926:Escherichia coli / Q000502:physiology*; D006801:Humans; D053583:Interleukin-1beta / Q000032:analysis; D015850:Interleukin-6 / Q000032:analysis; D008156:Luciferases / Q000032:analysis; D008264:Macrophages / Q000276:immunology; D008297:Male; D008795:Metronidazole / Q000627:therapeutic use; D051379:Mice; D008810:Mice, Inbred C57BL; D023421:Models, Animal; D009195:Peroxidase / Q000032:analysis; D019936:Probiotics; D015398:Signal Transduction / Q000502:physiology; D051996:Transcription Factor RelA / Q000032:analysis / Q000378:metabolism; D014409:Tumor Necrosis Factor-alpha / Q000032:analysis
D000890:Anti-Infective Agents; D053583:Interleukin-1beta; D015850:Interleukin-6; D051996:Transcription Factor RelA; D014409:Tumor Necrosis Factor-alpha; D008795:Metronidazole; D009195:Peroxidase; D008156:Luciferases