Antibacterial and anti-inflammatory activities of Parotid Secretory Protein

项目描述（由申请人提供）：本项目的长期目标是确定腮腺分泌蛋白（PSP; SPLUNC2）在口腔中是否具有双重功能的宿主防御蛋白。PSP在唾液腺、口腔上皮细胞和唾液中表达，但其功能尚不清楚。细菌和肿瘤坏死因子上调PSP的表达，PSP的硅晶结构分析显示其可能类似于杀菌/通透性增加蛋白（BPI）和脂多糖结合蛋白（LBP）。根据这两种蛋白活性结构域的定位，设计了几种PSP肽，并发现它们在体内和体外都具有抗菌和抗内毒素活性。基于这些PSP肽的初步结果和完整PSP的额外初步数据，我们假设PSP肽检测到的抗菌和抗炎双重功能反映在完整PSP蛋白的生物活性上。两个具体目标将测试PSP的拟议功能。目的1描述PSP的抗菌活性。PSP多肽和重组PSP将用于生化、细胞生物学和体内实验，以确定PSP是否具有抑菌或杀菌活性、细菌凝集和抑制生物膜形成。目的2将描述PSP的抗炎活性。PSP肽和重组PSP将用于生化、细胞生物学和体内实验，以确定PSP是否与LPS结合，在体外阻断LPS的作用，并在LPS诱导的脓毒症模型中保护小鼠。如果得到证实，PSP的功能将扩大在口腔中表达并参与口腔黏膜防御的抗菌宿主防御蛋白群。因此，这里提出的研究将为未来旨在对抗感染和控制炎症的新临床方法的转化研究奠定基础。

DESCRIPTION (provided by applicant): The long-term goal of this project is to determine if Parotid Secretory Protein (PSP; SPLUNC2) is a dual function host-defense protein in the oral cavity. PSP is expressed in salivary glands, oral epithelial cells and saliva but its function is unknown. Expression of PSP is up-regulated by bacteria and TNF and an in silico structural analysis of PSP revealed that it may be similar to bactericidal/permeability increasing protein (BPI) and LPS-binding protein (LBP). Guided by the location of active domains in these two proteins, several PSP peptides were designed and found to exhibit both antibacterial and anti-endotoxin activities in vitro and in vivo. Based on these initial results with PSP peptides and additional preliminary data for intact PSP it is hypothesized that the dual- function antibacterial and anti-inflammatory activities detected for PSP peptides are reflected in the biological activity of the intact PSP protein. Two specific aims will test the proposed functions of PSP. Aim 1 will characterize the antibacterial activity of PSP. PSP peptides and recombinant PSP will be used in biochemical, cell biological and in vivo experiments to determine if PSP exhibits bacteriostatic or bactericidal activity, bacterial agglutination, and inhibition of biofilm formation. Aim 2 will characterize the anti- inflammatory activity of PSP. PSP peptides and recombinant PSP will be used in biochemical, cell biological and in vivo experiments to determine if PSP binds LPS, blocks the action of LPS in vitro and protects mice in an LPS-induced sepsis model. If confirmed, the proposed functions of PSP will expand the group of antimicrobial host- defense proteins that are expressed in the oral cavity and participate in the defense of the oral mucosa. Thus, the research proposed here will lay the foundation for future translational research aimed at novel clinical approaches to combat infection and control inflammation. PUBLIC HEALTH RELEVANCE: The goal of this proposal is to identify the biological functions of the salivary protein Parotid Secretory Protein (PSP). Preliminary data suggest that PSP plays a role in host-defense against oral and airway bacteria. Peptides based on the PSP sequence may have clinical utility as antibacterial or anti-inflammatory components.