de Buhr Maike F, Mähler Michael, Geffers Robert, Hansen Wiebke, Westendorf Astrid M, Lauber Jörg, Buer Jan, Schlegelberger Brigitte, Hedrich Hans J, Bleich Andre
Central Animal Facility, Institute for Laboratory Animal Science, Hannover Medical School, Hannover, Germany.
Physiol Genomics. 2006 May 16;25(3):426-34. doi: 10.1152/physiolgenomics.00022.2005.
Induction of inflammatory bowel (IBD)-like disease in mice by a targeted mutation in the Il10 gene (Il10(-/-)) is inbred strain dependent. C3H/HeJBir (C3) mice are colitis susceptible, whereas C57BL/6J (B6) mice are resistant. Genetic dissection of this susceptibility revealed 10 colitogenic quantitative trait loci (QTL). The aim of this study was to identify valuable candidate genes by a combination of QTL mapping and microarray analyses. Sixteen genes were differentially expressed between B6- and C3-Il10(-/-) mice and were located within the QTL intervals. Three major candidate genes (Cd14, Gbp1, Pla2g2a) showed prominent expression differences between B6- and C3-Il10(-/-) as well as between B6 and C3 wild-type mice, which was confirmed by semiquantitative or real-time RT-PCR. Because strain differences are known for Gbp1 and Pla2g2a, further analyses focused on Cd14. Western blot analysis revealed strain differences also on the protein level. Cd14 expression in animals with defective and intact Toll-like receptor (TLR)4 signaling (C3, C3H/HeN, B6, B6-Tlr4(tm1Aki)) make the TLR4 defect of C3 mice unlikely to be the reason for higher Cd14 expression. Less Cd14 expression in germ-free mice indicates a contribution of the microflora on Cd14 expression. Stimulation of naive peritoneal macrophages with bacterial antigens showed lower CD14 surface expression in B6 than in C3 mice. In conclusion, the large number of candidate genes was reduced to three major candidates that play an important role in inflammatory processes and immune response. Strain differences for them are already known or are shown in this study.
通过Il10基因（Il10-/-）的靶向突变在小鼠中诱导炎症性肠病（IBD）样疾病具有近交系依赖性。C3H/HeJBir（C3）小鼠易患结肠炎，而C57BL/6J（B6）小鼠具有抗性。对这种易感性进行基因剖析发现了10个致结肠炎数量性状位点（QTL）。本研究的目的是通过QTL定位和微阵列分析相结合的方法来鉴定有价值的候选基因。16个基因在B6和C3 Il10-/-小鼠之间差异表达，且位于QTL区间内。三个主要候选基因（Cd14、Gbp1、Pla2g2a）在B6和C3 Il10-/-小鼠之间以及B6和C3野生型小鼠之间表现出显著的表达差异，这通过半定量或实时RT-PCR得到了证实。由于已知Gbp1和Pla2g2a存在品系差异，因此进一步的分析集中在Cd14上。蛋白质印迹分析显示在蛋白质水平上也存在品系差异。在具有缺陷和完整Toll样受体（TLR）4信号传导的动物（C3、C3H/HeN、B6、B6-Tlr4(tm1Aki)）中Cd14的表达表明C3小鼠的TLR4缺陷不太可能是Cd14表达较高的原因。无菌小鼠中Cd14表达较低表明微生物群对Cd14表达有影响。用细菌抗原刺激未活化的腹膜巨噬细胞显示，B6小鼠的CD14表面表达低于C3小鼠。总之，大量候选基因被减少到三个主要候选基因，它们在炎症过程和免疫反应中起重要作用。本研究已经了解或显示了它们的品系差异。
