Antibactrial degradation products of extracellular matrix bioscaffolds

描述(申请人提供)：由细胞外基质(ECM)组成的生物支架在临床前研究和人类临床应用中已成功用作许多组织的结构性重建的模板。这些基于ECM的支架对细菌感染具有惊人的抵抗力，即使在细菌污染风险很高的临床应用中也是如此。细菌耐药特性与ECM的降解有关，并且似乎依赖于ECM的降解。在没有降解的情况下，ECM支架实际上可以支持细菌的生长。这项拟议的工作将研究ECM发挥抗菌活性的机制，这种活性的组织特异性，以及一种常见的生物支架加工方法，即化学交联法，对ECM的抗菌潜力的潜在有害影响。未经化学交联(如碳二亚胺)处理的ECM支架在体内会迅速降解，而体外通过化学和物理方法降解的ECM支架已被证明产生具有抗菌活性的隐蔽多肽。拟议的研究将确定ECM支架降解产物的抗菌活性是否具有部位/组织特异性。换句话说，我们将确定真皮和肝脏ECM的降解产物是否分别对皮肤和肝脏中常见的细菌显示出最强的活性。提出了三个具体的目标：1)确定皮肤和肝脏ECM支架的抗菌降解产物是否可以通过模拟生理条件的方法在体外产生；2)确定皮肤或肝脏ECM支架的降解产物是否具有特定部位的抗菌活性；3)分离和纯化来自真皮和肝脏ECM支架的抗菌肽。提出了明确的目标和成功完成这些具体目标的方法。这项拟议的工作可能会导致鉴定新的抗菌肽，这些抗菌肽可以批量生产用于治疗。这项工作还将阐明使用非化学交联的ECM支架用于再生医学应用的好处，特别是在细菌感染的高可能性部位。最后，拟议的工作将提供更好的了解细胞外基质降解在与细胞外基质支架相关的细菌耐药性中的作用，以及在哺乳动物先天免疫中的作用。

DESCRIPTION (provided by applicant): Biologic scaffolds composed of extracellular matrix (ECM) have been successfully used as templates for the constructive remodeling of numerous tissues in preclinical studies and human clinical applications. These ECM-based scaffolds have been surprisingly resistant to bacterial infection, even in clinical applications that are at high risk for bacterial contamination. The bacterial resistance property is associated with, and appears dependent upon, degradation of the ECM. In the absence of degradation, ECM scaffolds can actually support bacterial growth. The proposed work will investigate the mechanism by which ECM exerts antimicrobial activity, the tissue specificity of this activity, and the potential detrimental effect of a common method of processing biologic scaffolds, i.e., chemical crosslinking, upon the antimicrobial potential of the ECM. ECM scaffolds that are not processed by chemical crosslinking (e.g., carbodiimide) are rapidly degraded in vivo, and degradation of ECM scaffolds in vitro by chemical and physical methods has been shown to generate occult peptides that possess antimicrobial activity. The proposed studies will determine if the antimicrobial activity derived from degradation products of ECM scaffolds has site/tissue specificity. Stated differently, we will determine if the degradation products of dermal and liver ECM show their most potent activity against those bacteria that are commonly found in the skin and liver, respectively. Three specific aims are proposed: 1) To determine if antimicrobial degradation products of dermal and liver ECM scaffolds can be produced in vitro by methods that mimic physiologic conditions; 2) To determine if degradation products of skin or liver ECM scaffolds have antimicrobial activity with site-specific activity; and 3) To isolate and purify antimicrobial peptides derived from dermal and liver ECM scaffolds. Clearly defined objectives and methods to successfully complete these specific aims are presented. The proposed work could potentially lead to the identification of novel antimicrobial peptides that could be produced in bulk for therapeutic use. This work will also elucidate the benefits of using non-chemically crosslinked ECM scaffolds for regenerative medicine applications, particularly in sites with high potential for bacterial infection. Finally, the proposed work will provide a better understanding of the role of ECM degradation in bacterial resistance associated with ECM scaffolds, as well as in mammalian innate immunity.