BChE reactivators for nerve agent and pesticide OP detoxification in human tissue

BChE再活化剂用于人体组织中神经毒剂和农药OP解毒 项目概述：我们提出开发一种以前未探索的神经治疗方法， 基于内源BChE有效再活化的制剂和农药OP暴露 直接进入人体循环和组织。这种方法主要基于加速OP 直接在组织中降解，在组织中，OP首先进入和/或积累， exposure.肟通过天然存在于肺、肠和胃中的BChE辅助OP水解。 血浆，从而提供了一个障碍，随后分布的OP的目标位点，在骨骼 肌肉和中枢神经系统我们最近展示了作为原理的证明，肟的功能 体外、离体和体内辅助的、基于BChE的催化OP生物清除剂（Radi et 例如，Biochem J 450，2013，231 - 242）。我们证明了TAB 2OH，一种新开发的肟， 人BChE的再活化剂具有足够的能力快速再活化无活性的共价OP- BChE在体外缀合物，并增强OP暴露小鼠的保护和治疗， 与纯化的BChE组合施用。我们现在建议利用内源性人类 BChE以nM浓度天然存在于肺、肠和血浆中，而不是 施用纯化的BChE，并且仅施用高效的BChE再活化剂以辅助 内源BChE在OP降解中的作用。我们认为这是可能的，因为我们最近 开发了一系列基于叔和季咪唑的hBChE再活化剂， 在体外比TAB2OH有效数倍。叔胺具有额外的 血脑屏障和肺泡膜渗透的潜力和口服生物利用度。我们 建议研究新的BChE再激活剂在OP暴露小鼠中的体内功效，并进一步 细化其结构以改善其再活化性能。这项R21提出的研究， 通过在体外积累hBChE的再活化和周转的动力学参数， OP的存在并将最佳化合物用于小鼠体内分析， 揭示内源性BChE再激活在解毒治疗中的潜力。还应当 导致确定最有效的剂量方案和评估的限制， 通过肟辅助提高内源性BChE的潜力 催化作用简而言之，口服或胃肠外肟是否有一个OP暴露水平， 重新激活BChE是有效的，而不必诉诸繁琐和风险- 在田间和非无菌条件下加强相关的BChE活性？

BChE reactivators for nerve agent and pesticide OP detoxification in human tissue Project Summary: We propose to develop a previously unexplored approach in therapy of nerve agent and pesticide OP exposure based on efficient reactivation of endogeneous BChE directly in human circulation and tissues. This approach is largely based on accelerated OP degradation of OPs directly in tissues where OPs enter and/or accumulate first during an exposure. Oxime assisted OP hydrolysis by BChE naturally present in lungs, intestine and plasma, thus provides a barrier to subsequent distribution of OPs to target sites in skeletal muscle and CNS. We recently demonstrated as a proof of principle, the functioning of oxime assisted, BChE based, catalytic OP bioscavenger in vitro, ex vivo and in vivo (Radi et al.,Biochem J 450, 2013,231-242). We demonstrated that TAB2OH, a newly developed oxime reactivator of human BChE had sufficient capacity to rapidly reactivate inactive, covalent OP- BChE conjugates in vitro, and enhance both protection and therapy of OP exposed mice when administered in combination with purified BChE. We now propose to utilize endogenous human BChE naturally present in lungs, intestine and plasma at nM concentrations instead of administering purified BChE, and to administer only highly efficient BChE reactivator to assist endogenous BChE in OP degradation. We assume that this will be possible since we recently developed a series of tertiary and quaternary imidazole based hBChE reactivators that are several fold more efficient in vitro than TAB2OH. The tertiary amines have the additional potential for blood-brain barrier and alveolar membrane permeation and oral bioavailability. We propose to investigate in vivo efficacy of new BChE reactivators in OP exposed mice and further refine their structure to improve their reactivation properties. This R21 proposed research, through accumulating in vitro kinetic parameters of reactivation and turnover of hBChE in the presence of an OP and taking the optimal compounds to an in vivo analysis in mouse, should uncover the potential of endogenous BChE reactivation in antidotal therapy. It should also lead to ascertaining the most efficacious dosage regimen and to assessing the limits of capitalizing on enhancing the potential of endogenous BChE through oxime-assisted catalysis. In short, is there an OP exposure level where oral or parenteral oximes directed to reactivating BChE are efficacious without having to resort to the cumbersome and risk- associated BChE fortification of activity in field and non-sterile conditions?