Bianchi M, Ulrich P, Bloom O, Meistrell M, Zimmerman G A, Schmidtmayerova H, Bukrinsky M, Donnelley T, Bucala R, Sherry B
Picower Institute for Medical Research, Manhasset, New York 11030, USA.
Mol Med. 1995 Mar;1(3):254-66.
Nitric oxide (NO), a small effector molecule produced enzymatically from L-arginine by nitric oxide synthase (NOS), is a mediator not only of important homeostatic mechanisms (e.g., blood vessel tone and tissue perfusion), but also of key aspects of local and systemic inflammatory responses. Previous efforts to develop inhibitors of NOS to protect against NO-mediated tissue damage in endotoxin shock have been unsuccessful, largely because such competitive NOS antagonists interfere with critical vasoregulatory NO production in blood vessels and decrease survival in endotoxemic animals. Accordingly, we sought to develop a pharmaceutical approach to selectively inhibit NO production in macrophages while sparing NO responses in blood vessels.
The process of cytokine-inducible L-arginine transport and NO production were studied in the murine macrophage-like cell line (RAW 264.7). A series of multivalent guanylhydrazones were synthesized to inhibit cytokine-inducible L-arginine transport. One such compound (CNI-1493) was studied further in animal models of endothelial-derived relaxing factor (EDRF) activity, carrageenan inflammation, and lethal lipopolysaccharide (LPS) challenge.
Upon activation with cytokines, macrophages increase transport of L-arginine to support the production of NO by NOS. Since endothelial cells do not require this additional arginine transport to produce NO, we reasoned that a competitive inhibitor of cytokine-inducible L-arginine transport would not inhibit EDRF activity in blood vessels, and thus might be effectively employed against endotoxic shock. CNI-1493, a tetravalent guanylhydrazone, proved to be a selective inhibitor of cytokine-inducible arginine transport and NO production, but did not inhibit EDRF activity. In mice, CNI-1493 prevented the development of carrageenan-induced footpad inflammation, and conferred protection against lethal LPS challenge.
A selective inhibitor of cytokine-inducible L-arginine transport that does not inhibit vascular EDRF responses is effective against endotoxin lethality and significantly reduces inflammatory responses.
一氧化氮（NO）是一种由一氧化氮合酶（NOS）从L-精氨酸酶促产生的小分子效应分子，它不仅是重要稳态机制（如血管张力和组织灌注）的介质，也是局部和全身炎症反应关键方面的介质。先前开发NOS抑制剂以预防内毒素休克中NO介导的组织损伤的努力均未成功，主要是因为此类竞争性NOS拮抗剂会干扰血管中关键的血管调节性NO生成，并降低内毒素血症动物的存活率。因此，我们试图开发一种药物方法，以选择性抑制巨噬细胞中的NO生成，同时保留血管中的NO反应。
在小鼠巨噬细胞样细胞系（RAW 264.7）中研究细胞因子诱导的L-精氨酸转运和NO生成过程。合成了一系列多价胍腙以抑制细胞因子诱导的L-精氨酸转运。在血管内皮衍生舒张因子（EDRF）活性、角叉菜胶炎症和致死性脂多糖（LPS）攻击的动物模型中进一步研究了一种此类化合物（CNI-1493）。
在用细胞因子激活后，巨噬细胞增加L-精氨酸的转运以支持NOS生成NO。由于内皮细胞产生NO不需要这种额外的精氨酸转运，我们推断细胞因子诱导的L-精氨酸转运的竞争性抑制剂不会抑制血管中的EDRF活性，因此可能有效地用于对抗内毒素休克。四价胍腙CNI-1493被证明是细胞因子诱导的精氨酸转运和NO生成的选择性抑制剂，但不抑制EDRF活性。在小鼠中，CNI-1493可预防角叉菜胶诱导的足垫炎症的发展，并赋予对致死性LPS攻击的保护作用。
一种不抑制血管EDRF反应的细胞因子诱导的L-精氨酸转运的选择性抑制剂对内毒素致死有效，并显著降低炎症反应。
