OLEFINIC ANALOGS OF CSA: NEW AGENTS

环孢素A是一种由11个氨基酸组成的环状多肽，临床应用广泛。 已证实的器官领域的选择性免疫调节活性 移植(心、肝、肺、肾和骨髓)和自体移植 免疫紊乱(葡萄膜炎、1型糖尿病、类风湿性关节炎、 等)尽管这种强效和临床上令人印象深刻的免疫抑制剂 由于其副作用：肾毒性，它的使用受到了限制。 (主要副作用，不可逆转的纤维化)，肝毒性和 神经毒性。这些毒性的表达机制并不是 已知的，毒性只能通过监测药物来部分控制 血液水平。因此，开发一种更安全的模拟设备将大大扩展 这类强大的免疫抑制剂的临床效用。 这项提议的长期目标是开发一种类似于 更高效力、更具选择性和/或不同免疫抑制剂的CsA 活性和毒性降低。所针对的具体目标 朝着这个长远目标是：半合成一系列烯烃 氨基酸1类似物(一种关键氨基酸)的体外评价 对这些类似物的免疫抑制活性进行体内评价 类似物的肾毒性及后两者的相关性 具有类似物三维溶液结构的活动为 由核磁共振波谱测定。半合成方法的研究进展 CsA类似物已经开发出来，涉及一种氧化 残基1中的双带断裂，然后进行烯化反应。这个 体外免疫抑制活性的评估将是 通过涉及抑制IL-2产生的已知程序来实现， 抑制胸腺细胞增殖，竞争结合(环孢素A与类似物) 亲环素(CsA受体)和CsA单抗对类似物的识别。 肾毒性的评估将在以前使用的大鼠身上进行 通过评价肾功能(GFR、BUN和肌酐水平)和 肾脏形态(光镜：细胞增殖、小管细胞 空泡化、小管萎缩和纤维化)。这后两个 特征将与三维结构相关 将通过使用一维和二维核磁共振确定的类似物 光谱技术与三维结构分析程序 DSPACE。这些研究的结果将导致 结构-活动关系将导致 更安全、更强大的CsA免疫抑制类似物。

Cyclosporin A is an eleven amino acid, cyclic peptide with clinically proven selective immunoregulatory activity of the fields of organ transplantations (hear, liver, lung, kidney and bone marrow) and auto- immune disorders (uveitus, type 1 diabetes mellitus, rheumatoid arthritis, etc.) Despite this potent and clinically impressive immunosuppressant activity, its use has been restricts by its side effects: nephrotoxicity (major side effect, irreversible fibrosis), hepatotoxicity and neurotoxicity. The mechanisms of expression of these toxicities are not known and the toxicities are only partially controlled by monitoring drug blood levels. Thus the development of a safer analog would greatly expand the clinical utility of this powerful class of immunosuppressants. The long term objective of this proposal is the development of an analog of CsA with higher potency, more selective and/or different immunosuppressant activity and decreased toxicity. The specific aims that are directed towards this long term goal are: the semi-synthesis of a series of olefin analogs of amino acid 1 (a critical amino acid), the in vitro evaluation of the immunosuppressant activity of these analogs, the in vivo evaluation of the nephrotoxicity of the analogs and the correlation of the latter two activities with the 3 dimensional solution structure of the analogs as determined by NMR spectroscopy. The procedure for the semi-synthesis of the CsA analogs has already been developed and involves an oxidative cleavage of the double band in residue 1 followed by olefination. The evaluation of the in vitro immunosuppressant activities will be accomplished by known procedures involving inhibition of IL-2 production, inhibition of thymocyte proliferation, competitive binding (CsA vs analog) to cyclophilin (putative CsA receptor) and analog recognition by CsA MAB. The evaluation of nephrotoxicity will be done in the previously used rat model by evaluation of kidney function (GFR,BUN and creatinine levels) and kidney morphology (light microscopy: cell proliferation, tubule cell vacuolization, tubule atrophification and fibrosis). These latter two characteristics will be correlated to the 3 dimensional structure of the analogs which will be determined by the use of 1 and 2 dimensional NMR spectroscopy techniques and the 3 dimensional structure analysis program DSPACE. The results of these studies will lead to the development of structure-activity relationships which will lead to the development of safer, more powerful CsA immunosuppressant analogs.