MUCOSAL CELL CARRIERS/ENZYMES IN ORAL DRUG ABSORPTION

拟议研究的目标是确定生物化学和 胃肠道吸收的分子遗传学机制 类肽类药物和开发改善口腔功能的方法 药物在人体内的传递。快速药理筛选 与组合综合方法相结合的方法论 产生了一系列具有潜在治疗作用的化合物。 然而，其治疗效用尤其是多肽和多肽型 药物的口服吸收很低，这严重限制了药物的使用。建议数 研究将利用新的分子生物学结果和 促进我们对多肽转运的理解的方法学。这些 方法将与肠膜的测定相结合 细胞、动物和人类系统的渗透性允许交叉 包括人类在内的物种之间的相互关系。最后，这项建议 将利用这种多肽开发前药策略的扩展 转运体被发现成功地改善了口腔系统 极性化合物的输送。拟议项目的具体目标 确定肠道和肝脏的结构要求 类肽类化合物的转运及其机制的扩展 细胞、组织、动物和人体吸收之间的相关性。胡麻B. 扩展上皮细胞的结构-运输关系和 肝细胞转运作为口服药物前药设计的基础 提供并评估此策略在提高口语能力方面的有效性 送货。C.确定介导肽转运的基因并进行比较 用从人结肠癌HT-29细胞中克隆的基因在 我们的实验室和建立转基因细胞系用于机械化 类肽转运的研究。D.确定亚细胞的分布 多肽转运蛋白基因及其在细胞中的功能表达 在细胞培养、肠和肝组织中通过 免疫组织化学和转运分析，并确定需求 转运蛋白在质膜上的功能表达 浮出水面。E.确定多肽转运蛋白的功能结构域 利用序列分析和定点突变，并开发出一种 用于理解底物结合和转运的结构模型 分子水平。F.开发一个非线性吸收模型，其中包括 肠道和肝脏的通透性，包括部位依赖性 渗透性、非线性吸收、酶水解率和转运率 这可以用来预测人类的口服吸收。 因此，拟议的研究项目将结合分子生物学 结合细胞、动物和人体研究的方法来建立 多肽类药物吸收的机制基础。它会发展成 分子和动力学信息，并利用这些知识开发 并测试评估和改进 类肽药物的生物利用度。这种研究合作使我们能够 在当前研究方法和方法的最前沿工作 为真正影响多肽类药物的口服给药提供了机会 毒品。

The goal of the proposed research is to determine the biochemical and molecular genetic mechanisms underlying the gastrointestinal absorption of peptoid-type drugs and to develop approaches to improving the oral delivery of drugs in humans. Rapid pharmacological screening methodologies combined with combinatorial synthetic approaches has produced a diverse array of compounds of potential therapeutic utility. However, the therapeutic utility particularly for peptide and peptide-type drugs is severely limited by their low oral absorption. The proposed research will take advantage of new molecular biological results and methodologies to advance our understanding of peptide transport. These approaches will be combined with the determination of intestinal membrane permeabilities in cell, animal and human systems allowing for cross- correlations between species including humans. Finally, this proposal will develop extensions of a prodrug strategy utilizing the peptide transporter found to be successful for improving the oral systemic delivery of polar compounds. The specific aims of the proposed project are: A. Determine the structural requirements for intestinal and hepatic transport of peptoid-type compounds and extend the mechanistic correlations between cell, tissue, animal and human absorption. B. Extend the structure-transport relationship for epithelial cell and hepatocyte transport as a basis for the design of prodrugs for oral drug delivery and evaluate the effectiveness of this strategy in improving oral delivery. C. Identified genes mediating peptide transport and compare with the cloned gene from human colon carcinoma HT-29 cells identified in our laboratories and establish transfected cell lines for mechanistic studies of peptoid transport. D. Determine the subcellular distribution of the peptide transporter genes and functional expression at the cell surface in cell culture, intestine, and liver tissue through immunohistochemistry and transport assays and determine the requirements for functional expression of the transporter at the plasma membrane surface. E. Identify the functional domains of the peptide transporters using sequence analysis and site-directed mutagenesis, and develop a structural model to understand substrate binding and transport at the molecular level. F. Develop a nonlinear absorption model incorporating intestinal and hepatic permeability, including site dependent permeability, nonlinear absorption, enzyme hydrolysis and transit rate that can be used to predict human oral absorption. Thus the proposed research project will combine molecular biological approaches with integrated cellular, animal and human studies to establish the mechanistic basis for peptide type drug absorption. It will develop molecular and kinetic information and utilize this knowledge to develop and test integrated approaches to estimating and improving the bioavailability of peptoid drugs. This research collaboration allows us to work at the very frontier of current research methodologies and provides an opportunity to truly impact oral drug delivery of peptide-type drugs.