Aldose Reductase: A Regulator of Inflammatory Signals

描述(申请人提供)：我们最近的研究表明，醛糖还原酶(AR)在脂质过氧化产生的脂类衍生醛(LDAs)及其与GSH的偶联物的解毒过程中起着关键的作用。AR能有效降低脂质过氧化过程中产生的毒性最大、含量最高的LDA之一4-羟基反式-2-壬烯醛(HNE)和GS-HNE。我们进一步证明，AR介导了由肿瘤坏死因子-α、生长因子和高血糖产生的活性氧自由基(ROS)的有丝分裂和细胞毒信号，分别导致血管平滑肌细胞和血管内皮细胞的增殖和凋亡。我们还观察到，用特异性抑制剂抑制AR，或用反义或RNAi消融AR，可减弱PKC和MAPK的激活、IkappaB-α的磷酸化和降解以及NF-kappaB和API的激活。此外，AR抑制可减弱脂多糖(LPS)诱导的小鼠腹腔巨噬细胞分泌细胞因子，如TNF-α、IL-6和IL-10、次级信使cAMP和前列腺素E2。我们的假设是，AR在通过ROS介导的内毒素诱导的炎症反应的转导中起着关键作用。现在，我们将通过研究脂多糖诱导的小鼠腹膜巨噬细胞和RAW246.7细胞释放细胞因子和趋化因子来系统地检验我们的假设，并确定AR消融抑制这些细胞毒信号的机制(S)。我们将在肝、脾、小肠、肾、心脏和血清中研究AR抑制对内毒素诱导的炎症细胞因子和趋化因子的抑制作用，并将其与小鼠组织炎症的减轻相关联。因此，我们的目标是：1)阐明AR在细菌内毒素诱导的巨噬细胞细胞毒信号中的作用；2)研究AR在细菌内毒素诱导的小鼠巨噬细胞促炎细胞因子和趋化因子表达中的作用；3)确定AR的分子机制和可能的靶点；4)探讨AR在小鼠体内调节细胞因子和趋化因子生成以及炎症反应中的作用。这些研究的完成将揭示AR抑制剂如何减弱ROS介导的内毒素和细胞因子信号，为预防炎症毒性提供新的治疗途径，并阐明AR参与这些并发症的分子机制(S)。

DESCRIPTION (provided by applicant): Our recent studies have demonstrated that aldose reductase (AR), plays a pivotal rote in the detoxification of lipid peroxidation-generated lipid derived aldehydes (LDAs) and their conjugates with GSH. 4-hydroxy trans-2-nonenal (HNE), one of the most toxic and abundant LDA generated during lipid peroxidation and GS-HNE are efficiently reduced by AR. We have further demonstrated that AR mediates the mitogenic and cytotoxic signals of reactive oxygen species (ROS) generated by TNF-alpha, growth factors and hyperglycemia leading to proliferation and apoptosis of vascular smooth muscle cells and vascular endothelial cells, respectively. We have also observed that inhibition of AR by specific inhibitors or ablation of AR by antisense or RNAi attenuates the activation of PKC and MAPK, phosphorylation and degradation of IkappaB-alpha and activation of NF-kappaB and API. Also, AR inhibition attenuates lipopolysaccharide (LPS)-induced secretion of cytokines such as TNF-alpha, IL-6, and IL-10, secondary messenger cAMP and prostaglandin E2 in mouse peritoneal macrophages. Our hypothesis is that AR plays a pivotal role in the transduction of LPS-induced inflammatory responses mediated via ROS. We will now systematically examine our hypothesis by investigating the release of LPS-induced cytokines and chemokines by mouse peritoneal macrophages and RAW246.7 cells and identify the mechanism(s) of inhibition of these cytotoxic signals by AR ablation. Attenuation of LPS-induced inflammatory cytokines and chemokines by AR inhibition will be investigated in the liver, spleen, small intestine, kidney, heart and serum, and correlated with attenuation of inflammation in tissues of mice. Thus our aims are to 1) Delineate the involvement of AR in bacterial endotoxin (LPS)-induced cytotoxic signals in macrophages, 2) Investigate the role of AR in LPS-induced expression of proinflammatory cytokines and chemokines in mouse macrophages, 3) Identify the molecular mechanisms and possible targets of AR and 4) Investigate the in vivo role of AR in the regulation of cytokine and chemokine generation and inflammation in mice. Completion of these studies will demonstrate how AR inhibitors attenuate the ROS-mediated LPS and cytokine signals, provide a novel therapeutic approach for preventing inflammation-induced toxicity and elucidate the molecular mechanism(s) of AR's involvement in these complications.