Louis Nancy A, Robinson Andreas M, MacManus Christopher F, Karhausen Jörn, Scully Melanie, Colgan Sean P
Neonatology Division, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA.
J Immunol. 2008 Mar 15;180(6):4246-55. doi: 10.4049/jimmunol.180.6.4246.
Inflammatory diseases influence tissue metabolism, altering regulation of extracellular adenine nucleotides, with a resultant protective influence of adenosine. Ecto-5'-nucleotidase (CD73) is a central surface enzyme generating extracellular adenosine. Thus, we hypothesized that CD73 is protective in mucosal inflammation as modeled by trinitrobenzene sulfonate (TNBS) colitis. Initial studies revealed a >3-fold induction of CD73 mRNA levels after TNBS colitis. Additionally, the severity of colitis was increased, as determined by weight loss and colonic shortening, in cd73(-/-) mice relative to cd73(+/+) controls. Likewise, enteral administration of the selective CD73 inhibitor alpha,beta-methylene ADP to cd73(+/+) mice resulted in a similar increase in severity of TNBS colitis. Gene array profiling of cytokine mRNA expression, verified by real-time PCR, revealed a >90% down-regulation of IFN-alphaA in cd73(-/-) mice and alpha,beta-methylene ADP-treated cd73(+/+) mice, compared with cd73(+/+) mice. Exogenous administration of recombinant IFN-alphaA partially protected TNBS-treated cd73(-/-) mice. Cytokine profiling revealed similar increases in both IFN-gamma and TNF-alpha mRNA in colitic animals, independent of genotype. However, IL-10 mRNA increased in wild-type mice on day 3 after TNBS administration, whereas cd73(-/-) mice mounted no IL-10 response. This IL-10 response was restored in the cd73(-/-) mice by exogenous IFN-alphaA. Further cytokine profiling revealed that this IL-10 induction is preceded by a transient IFN-alphaA induction on day 2 after TNBS exposure. Together, these studies indicate a critical regulatory role for CD73-modulated IFNalphaA in the acute inflammatory phase of TNBS colitis, thereby implicating IFN-alphaA as a protective element of adenosine signaling during mucosal inflammation.
炎症性疾病会影响组织代谢，改变细胞外腺嘌呤核苷酸的调节，从而使腺苷产生保护性影响。胞外5'-核苷酸酶（CD73）是生成细胞外腺苷的关键表面酶。因此，我们推测CD73在三硝基苯磺酸（TNBS）诱导的结肠炎所模拟的黏膜炎症中具有保护作用。初步研究显示，TNBS诱导的结肠炎后CD73 mRNA水平诱导增加超过3倍。此外，相对于cd73(+/+)对照，cd73(-/-)小鼠的结肠炎严重程度增加，这通过体重减轻和结肠缩短来确定。同样，向cd73(+/+)小鼠肠内给予选择性CD73抑制剂α,β-亚甲基ADP会导致TNBS结肠炎严重程度出现类似增加。通过实时PCR验证的细胞因子mRNA表达基因芯片分析显示，与cd73(+/+)小鼠相比，cd73(-/-)小鼠和α,β-亚甲基ADP处理的cd73(+/+)小鼠中IFN-αA下调超过90%。外源性给予重组IFN-αA可部分保护TNBS处理的cd73(-/-)小鼠。细胞因子分析显示，无论基因型如何，结肠炎动物中IFN-γ和TNF-α mRNA均有类似增加。然而，TNBS给药后第3天，野生型小鼠中IL-10 mRNA增加，而cd73(-/-)小鼠没有IL-10反应。外源性IFN-αA可使cd73(-/-)小鼠恢复这种IL-10反应。进一步的细胞因子分析显示，这种IL-10诱导之前在TNBS暴露后第2天有短暂的IFN-αA诱导。总之，这些研究表明CD73调节的IFNαA在TNBS结肠炎的急性炎症期起关键调节作用，从而表明IFN-αA是黏膜炎症期间腺苷信号传导的保护因子。
