Novel Antimicrobials: Salivary MUC7 Peptides

描述：随着病原菌对常规抗菌药的耐药性的出现，以及一些抗菌药的毒性，迫切需要开发具有新作用机制的新药物。一个很有希望的来源是阳离子抗菌肽。我们发现人唾液粘蛋白MUC7多肽(来源于N-末端)在体外具有显著的广谱抗菌活性。这些阳离子多肽对多种真菌(例如，白色念珠菌和新生念珠菌，免疫功能低下患者中常见的机会性感染的细菌，尤其是艾滋病毒/艾滋病患者)，以及革兰氏阳性和阴性细菌(例如，变形链球菌，涉及龋齿和牙龈假单胞菌，涉及牙周疾病)有效。MUC7的20-聚体和12-聚体在口腔中发现的类似生理条件下保持相当大的杀念珠菌活性。12-聚体与组蛋白-5-12-聚体或两性霉素-B以协同或相加的方式对白色念珠菌和新生念珠菌起作用。最新添加的12-聚-D异构体在高离子强度缓冲液和唾液中显示出更强的杀灭念珠菌活性，并且比12-聚-L(自然形式)溶血更少。这些发现支持并加强了我们的假设，即这些新肽确实是治疗和预防抗菌剂的合适候选者。此外，它们对哺乳动物细胞的毒性很小或没有，并且引发耐药性的倾向很低。 本申请中提出的工作将进一步评估MUC7多肽在体外和体内作为治疗剂的潜力，并继续研究其作用机制。在具体目标1中，将详细检查MUC7 12肽的抗菌活性，包括与其他抗菌剂的结合。在具体目标2中，我们将通过基因表达谱探讨MUC7肽的作用机制，包括细胞内靶点(S)、与核酸的潜在结合、对蛋白质和核酸合成的抑制以及MUC7肽对白色念珠菌和酿酒酵母的影响。具体目标3将涉及这些多肽的生物可降解聚合物和/或水凝胶聚合物递送系统的配方和体外测试。在特定的目标4中，我们将测试专门设计的递送系统在体内模型中对抗真菌感染的有效性。总之，这些努力试图将MUC7肽推向临床应用的长期目标。

DESCRIPTION: With the emergence of pathogens resistant to conventional antimicrobials, and toxicity of some antimycotics, there is an urgent need for development of new agents with novel mechanisms of action. One promising source is cationic antimicrobial peptides. We have discovered that human salivary mucin MUC7 peptides (derived from the N-terminus) possess significant and broad-spectrum antimicrobial activity m vitro. These cationic peptides are effective against a variety of fungi (e.g., C. albicans and C. neoformans, organisms responsible for the common opportunistic infections in immunocompromised patients, particularly those with HIV/AIDS), and both Gram-positive and negative bacteria (e.g. S. mutans, implicated in dental caries and P. gingivalis, implicated in periodontal diseases). MUC7 20-mer and 12-mer retain considerable candidacidal activity in physiological-like conditions found in the oral cavity. The 12-mer in combination with histatin-5-12-mer or amphotericin-B acts in a synergistic or additive manner against C. albicans and C. neoformans. A newest addition, 12-mer-D isomer exhibits more potent candidacidal activity in high-ionic strength buffers and in saliva, and is less hemolytic than the 12-mer-L (natural form). These finding support and strengthen our hypothesis that these novel peptides are indeed suitable candidates for therapeutic and preventive antimicrobials. Further, that they will show little or no toxicity toward mammalian cells and will have low tendency to elicit resistance. The work proposed in this application will further evaluate the MUC7 peptide potential as therapeutic agents in vitro and m vivo, and continue to examine their mechanism of action. In Specific Aim 1, MUC7 12-mer peptide antimicrobial activity will be examined in detail, including in combination with other antimicrobial agents. In Specific Aim 2, we will address the mechanism of MUC7 peptide action, including intracellular target(s), potential binding to nucleic acid, inhibition of protein and nucleic acid synthesis, and the effect of MUC7 peptide on C. albicans and S. cerevisiae by gene expression profiling. Specific Aim 3 will address the formulation and in vitro testing of biodegradable polymeric and/or hydrogel polymeric delivery systems for these peptides. In Specific Aim 4, we will test the efficacy of the specifically design delivery systems against fungal infections in vivo models. Altogether, these efforts attempt to move the MUC7 peptides toward the long-range goal of clinical application.