Chemical Agents That Affect Biomembrane Function

描述(由申请人提供)：广泛的、长期的目标是合成和评估能够影响动态膜过程的有机分子，如融合、磷脂翻转、孔形成和细胞表面识别。进行这项研究有两个主要原因：(A)研究提供了对控制这些生物医学重要过程的超分子因素的有用洞察；(B)产生的有机化合物可用作膜生物学研究中的试剂、疾病诊断指标或药物先导。这项建议的具体目标是：1：开发一种人工合成的传感器，用于检测细胞表面磷脂酰丝氨酸(PS)的出现，这是细胞凋亡的标志。目前，染料标记的Annexin V被广泛用作PS敏感试剂来检测细胞凋亡，但这种基于蛋白质的检测方法存在一定的局限性。将使用并行合成和筛选方法来制备和鉴定一种合成的PS传感器，该传感器可以为血液、脾、淋巴结和骨髓等异质样本提供凋亡指数的定量测量。然后，这种PS传感器可以用来开发一种临床上有用的方法，来测量抗癌药物对个别患者的疗效。2：开发一种合成PS-扰乱酶，作为帮助身体清除致病细胞的新方法。平行合成和筛选方法将被用来鉴定一种能够扰乱PS跨质膜分布的有机化合物。假设外化PS浓度的增加将通过吞噬作用触发细胞清除。3：一种新的前药策略将选择性地将AIM 2中描述的诱导凋亡的化合物输送到前列腺癌细胞。前药由前列腺特异性膜抗原(PSMA)激活，PSMA存在于前列腺肿瘤细胞表面，数量增加。4：验证磷脂在融合、磷脂翻转、孔道形成和外周蛋白结合等重要的动态膜过程中可以采用延伸构象(非极性尾巴向相反方向延伸)的假设。实验方法是比较构象受限的极性脂类的超分子性质，这些极性脂不能采用完全扩展的构象，而更灵活的类似物可以。如果扩展构象假说得到证实，那么它代表了对磷脂动力学的一种新的、非常不同的观点。

DESCRIPTION (provided by applicant): The broad, long-term objectives are to synthesize and evaluate organic molecules that can affect dynamic membrane processes such as fusion, phospholipid flip-flop, pore formation and cell surface recognition. The research is conducted for two major reasons: (a) The studies provide useful insight into the supramolecular factors that control these biomedically important processes; (b) Organic compounds are produced that can be used as reagents in membrane biology research, diagnostic indicators of disease, or as pharmaceutical leads. The specific aims of this proposal are, 1: Develop a synthetic sensor for phosphatidylserine (PS) appearance on the surface of a cell which is a hallmark of cell apoptosis. Currently, dye-labeled Annexin V is used extensively as a PS-sensing reagent that detects apoptosis, but this protein-based detection method has a number of limitations. Parallel synthesis and screening methods will be used to prepare and identify a synthetic PS-sensor that can provide a quantitative measure of apoptotic index for heterogeneous samples such as blood, spleen, lymph nodes and bone marrow. This PS-sensor could then be used to develop a clinically useful method of measuring the efficacy of anticancer drugs in individual patients. 2: Develop a synthetic PS-scramblase as a new way to help the body eliminate pathogenic cells. Parallel synthesis and screening methods will be used to identify an organic compound that can scramble the distribution of PS across plasma membranes. It is hypothesized that an increase in the concentration of externalized PS will trigger cell clearance by phagocytosis. 3: A novel prodrug strategy will selectively deliver the apoptosisinducing compound described in aim 2 to prostate cancer cells. The prodrug is activated by the prostate specific membrane antigen (PSMA) that is present in elevated amounts on the surface of prostate tumor cells. 4: Test the hypothesis that phospholipids can adopt an extended conformation (the non-polar tails extend in opposite directions) during important dynamic membrane processes such as fusion, phospholipid flip-flop, pore formation and binding of peripheral proteins. The experimental approach is to compare the supramolecular properties of conformationally restricted polar lipids that are unable to adopt a fully extended conformation with more flexible analogues that can. If the extended conformation hypothesis is confirmed then it represents a new and very different view of phospholipid dynamics.