Enhanced expression of mRNA for nuclear factor kappaB1 (p50) in CD34+ cells of the bone marrow in rheumatoid arthritis.
Bone marrow CD34+ cells from rheumatoid arthritis (RA) patients have abnormal capacities to respond to tumor necrosis factor (TNF)-alpha and to differentiate into fibroblast-like cells producing matrix metalloproteinase (MMP)-1. We explored the expression of mRNA for nuclear factor (NF)kappaB in RA bone marrow CD34+ cells to delineate the mechanism for their abnormal responses to TNF-alpha. CD34+ cells were purified from bone marrow samples obtained from 49 RA patients and 31 osteoarthritis (OA) patients during joint operations via aspiration from the iliac crest. The mRNAs for NFkappaB1 (p50), NFkappaB2 (p52) and RelA (p65) were examined by quantitative RT-PCR. The expression of NFkappaB1 mRNA in bone marrow CD34+ cells was significantly higher in RA than in OA, whereas there was no significant difference in the expression of mRNA for NFkappaB2 and RelA. The expression of NFkappaB1 mRNA was not correlated with serum C-reactive protein or with the treatment with methotrexate or oral steroid. Silencing of NFkappaB1 by small interfering RNA abrogated the capacity of RA bone marrow CD34+ cells to differentiate into fibroblast-like cells and to produce MMP-1 and vascular endothelial growth factor upon stimulation with stem cell factor, granulocyte-macrophage colony stimulating factor and TNF-alpha without influencing their viability and capacity to produce beta2-microglobulin. These results indicate that the enhanced expression of NFkappaB1 mRNA in bone marrow CD34+ cells plays a pivotal role in their abnormal responses to TNF-alpha and, thus, in the pathogenesis of RA.
Hirohata
Shunsei
S
Department of Internal Medicine, Teikyo University School of Medicine, Tokyo 173-8605, Japan. shunsei@med.teikyo-u.ac.jp
Miura
Yasushi
Y
Tomita
Tetsuya
T
Yoshikawa
Hideki
H
Ochi
Takahiro
T
Chiorazzi
Nicholas
N
D000328:Adult; D000368:Aged; D018952:Antigens, CD34 / Q000378:metabolism*; D001172:Arthritis, Rheumatoid / Q000378:metabolism* / Q000473:pathology; D001854:Bone Marrow Cells / Q000187:drug effects / Q000378:metabolism* / Q000473:pathology; D002454:Cell Differentiation; D002478:Cells, Cultured; D005260:Female; D005347:Fibroblasts / Q000473:pathology; D020868:Gene Silencing; D016178:Granulocyte-Macrophage Colony-Stimulating Factor / Q000494:pharmacology; D006801:Humans; D008297:Male; D008875:Middle Aged; D052002:NF-kappa B p50 Subunit / Q000037:antagonists & inhibitors / Q000235:genetics*; D052003:NF-kappa B p52 Subunit / Q000235:genetics; D012333:RNA, Messenger / Q000378:metabolism*; D019089:Stem Cell Factor / Q000494:pharmacology; D051996:Transcription Factor RelA / Q000235:genetics; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology
D018952:Antigens, CD34; D052002:NF-kappa B p50 Subunit; D052003:NF-kappa B p52 Subunit; C498143:RELA protein, human; D012333:RNA, Messenger; D019089:Stem Cell Factor; D051996:Transcription Factor RelA; D014409:Tumor Necrosis Factor-alpha; D016178:Granulocyte-Macrophage Colony-Stimulating Factor