白介素-1受体相关激酶-2和磷脂酰肌醇3-激酶协同调控白介素-1诱导的NF-κB活化

Interleukin-1 receptor-associated Kinase-2 and phosphatidylinositol 3-kinase synergetically activate NF-κB

目的研究白介素１受体相关激酶２（ＩＲＡＫ－２）和磷脂酰肌醇 ３－激酶（ＰＩ ３－激酶）在白介素－１（ＩＬ－１）诱导核因子－κＢ（ＮＦ－κＢ）活化中的作用。方法 Ｌｉｐｏｆｅｃｔｉｏｎ介导反义ＩＲＡＫ－２寡核苷酸或反义ＰＩ３－激酶寡核苷酸转染ＨｅｐＧ２细胞后；用逆转录 ＰＣＲ法检测 ＩＲＡＫ－２ ｍＲＮＡ和ＰＩ３－激酶ｍＲＮＡ表达水平，以Ｓａｎｄｗｉｃｈ ＥＬＩＳＡ法检测ＮＦ－κＢ的活化。结果（１）反义ＩＲＡＫ－２寡核苷酸和反义ＰＩ３－激酶寡核苷酸分别抑制ＩＲＡＫ－２ ｍＲＮＡ和ＰＩ－３激酶ｍＲＮＡ的表达：（２）反义ＩＲＡＫ－２寡核苷酸或反义ＰＩ３－激酶寡核苷酸部分抑制ＮＦ－κＢ活化；（３）与反义ＩＲＡＫ－２寡核苷酸或反义ＰＩ ３－激酶寡核苷酸单独转染ＨｅｐＧ２细胞相比，反义ＩＲＡＫ－２寡核苷酸和反义ＰＩ ３－激酶寡核苷酸共转染ＨｅｐＧ２细胞对ＮＦ－ｋＢ的抑制作用明显增强。结论在ＨｅｐＧ２细胞中， ＩＲＡＫ－２和ＰＩ ３－激酶都调控 ＮＦ－κＢ活化但都不能完全激活 ＮＦ－κＢ，ＩＲＡＫ－２和 ＰＩ ３－激酶在调控 ＮＦ－κＢ活化时有协同作用。

objective To investigate the role of interleukin-1 receptor-associated kinase-2 (IRAK-2) and phosphatidylinositol 3-kinase (PI 3-kinase) in interleukin-1(IL-1)-induced nuclear factor-kB (NF-kB) activation. Methods Phosphorothioate oligonucleotides (ODN) were designed antisense to IRAK-2 or PI 3-kinase. Antisense IRAK-2 ODN or antisense PI 3-kinase ODN was delivered by lipofectin encapsulation into cultured HepG2 cells. IRAK-2 mRNA and PI 3-kinase mRNA expression was assayed by semiquantitative reverse transcription-PCR The levels of NF-kB were measured by sandwich ELISA. Results Antisense IRAK-2 ODN and antisense PI 3-kinase ODN blocked IRAK-2 and PI 3-kinase expression, respectively. As a result, antisense IRAK-2 ODN or antisense PI 3-kinase OON inhibited IL-1-induced NF-kB activation in a dose (1-8ug )-and time (5-24 h)-dependent fashion, When the cells were treated with antisense IRAK-2 ODN 4 u g or antisense PI 3-kinase ODN 2 u g for 8 h, the maximum inhibition rate was (54.5±0.2)% and (42.8±1.3)%, respectively However, Since the NF-kB activity was still much higher than that of basal group (P<0.01 ). the inhibition was incomplete. Cotransfection of antisense IRAK-2 ODN 4 u g with antisense PI 3-kinase ODN 2 u g resulted in an additive inhibition of NF-kB-activation by (80.3±0.5)%. Conclusions in In HepG2 cells. either IRAK-2 or PI 3-kinase is necessary but not sufficient to fully activate NF-kB, IRAK-2 regulates IL-1-stimulated NF-kB activation in cooperation with PI 3- kinase.