Effects of NF-kappaB1 (p50) targeted gene disruption on ionizing radiation-induced NF-kappaB activation and TNFalpha, IL-1alpha, IL-1beta and IL-6 mRNA expression in vivo.
OBJECTIVE
To investigate the role of the NF-kappaB1 (p50) gene in ionizing radiation (IR)-induced NF-kappaB activation and TNFalpha, IL-1alpha, IL-1beta and IL-6 mRNA expression in vivo.


METHODS
NF-kappaB activation was analysed by the gel shift/supershift assay and the levels of TNFalpha, IL-1alpha, IL-1beta and IL-6 mRNA were measured using RNase protection assay (RPA). Various tissues from BALB/c, B6,129P-Nfkb1 (NF-kappaB1 or p50 gene knockout, p50(-/-)) and B6,129PF2 (wild-type, p50(+/+)) mice were analysed before or after exposure to a lethal dose (8.5 Gy) of total-body gamma-irradiation.


RESULTS
Exposure of BALB/c mice to total-body IR selectively activated NF-kappaB in the spleen, mesenteric lymph nodes (LN) and bone marrow (BM). Gel supershift assay using polyclonal antibodies against NF-kappaB p50, p65 or c-Rel protein revealed that the NF-kappaB p50 subunit is a critical component of the NF-kappaB complexes activated by IR in vivo. Discretely augmented TNFalpha, IL-1alpha, IL-1beta and IL-6 mRNA expression was found in the spleen, LN and BM after BALB/c mice received IR. However, mice lacking the p50 gene (p50(-/-)) showed a significant reduction in IR-induced activation of NF-kappaB and increases in TNFalpha, IL-1alpha, IL-1beta and IL-6 mRNA expression, as compared with that of wild-type mice (p50(+/+)).


CONCLUSIONS
The NF-kappaB p50 subunit is a critical component of the NF-kappaB complexes activated by IR and it plays an important role in mediating IR-induced TNFalpha, IL-1alpha, IL-1beta and IL-6 mRNA expression in vivo.
Zhou
D
D
Division of Allergy, Immunology & Rheumatology, Department of Internal Medicine, University of Kentucky, Lexington, KY 40536, USA. zhoud@musc.edu
Yu
T
T
Chen
G
G
Brown
S A
SA
Yu
Z
Z
Mattson
M P
MP
Thompson
J S
JS
D000818:Animals; D001853:Bone Marrow / Q000528:radiation effects; D002467:Cell Nucleus / Q000378:metabolism; D004789:Enzyme Activation / Q000528:radiation effects*; D007375:Interleukin-1 / Q000378:metabolism*; D015850:Interleukin-6 / Q000378:metabolism*; D008198:Lymph Nodes / Q000528:radiation effects; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D018345:Mice, Knockout; D016297:Mutagenesis, Site-Directed; D016328:NF-kappa B / Q000235:genetics*; D052002:NF-kappa B p50 Subunit; D012333:RNA, Messenger / Q000378:metabolism*; D011839:Radiation, Ionizing; D012260:Ribonucleases / Q000378:metabolism; D013154:Spleen / Q000528:radiation effects; D013997:Time Factors; D014018:Tissue Distribution; D014158:Transcription, Genetic; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism*
D007375:Interleukin-1; D015850:Interleukin-6; D016328:NF-kappa B; D052002:NF-kappa B p50 Subunit; D012333:RNA, Messenger; D014409:Tumor Necrosis Factor-alpha; D012260:Ribonucleases