Functions of mammalian PGLYRPs in the cornea

哺乳动物 PGLYRP 在角膜中的功能

• 批准号: 8093360
• 负责人: Shukti Chakravarti
• 金额: $ 24.6万
• 依托单位: JOHNS HOPKINS UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-04-01 至 2013-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8093360
• 关键词: Affect; Age; Amidohydrolases; Anti-Bacterial Agents; Bacteria; Bacterial Infections; Biological Assay; Biology; Cell Culture Techniques; Cells; Clinical; Contact Lenses; Cornea; Corneal Injury; Debridement; Defense Mechanisms; Defensins; Enzyme-Linked Immunosorbent Assay; Epithelial; Epithelial Cells; Eye; Future; Genes; Healed; Health; Homeostasis; Human; Immune; Impaired wound healing; In Vitro; Infection; Inflammation; Inflammatory; Injury; Insecta; Keratitis; Knock-out; Knockout Mice; Lead; Letters; Ligands; Lung; Modeling; Molecular; Mus; Mutant Strains Mice; Natural Immunity; Nuclear; Operative Surgical Procedures; Outcome; Pathway interactions; Peptides; Peptidoglycan; Protein Family; Proteins; Pseudomonas; Pseudomonas aeruginosa; Regulation; Reporting; Research; Risk; Role; Signal Transduction; Small Interfering RNA; TLR2 gene; TLR4 gene; Testing; Therapeutic; Toll-Like Receptor 2; Transplantation; Trauma; Vision; Work; amidase; antimicrobial; antimicrobial peptide; bactericide; base; corneal epithelium; cytokine; experience; healing; improved; in vivo; killings; lumican; member; migration; mouse model; natural antimicrobial; pathogen; pathogenic bacteria; peptidoglycan recognition protein; prophylactic; receptor; response; skills; wound

DESCRIPTION (provided by applicant): The cornea is a transparent, refractive, protective mucosal barrier of the eye. Corneal infections pose a serious threat to healthy vision. Risks of infections increase with injury, surgery, daily contact lens wear and age. Research on antimicrobial proteins and peptides is critical for elucidating natural protective mechanisms in the cornea and therapies based on these. Our proposal focuses on the mammalian peptidoglycan recognition protein (PGLYRP) family of four antimicrobial proteins, which exist in various mucosal barriers, and identified just over a decade ago. We found PGLYRP1, and subsequently others PGLYRP2, -3 and -4 in the human and mouse cornea. Functions of mammalian PGLYRP members are generally underexplored, and in particular little is known of these in the eye. Much more is known of the large PGLYRP family in insects: they are mostly bactericidal, some hydrolyze peptidoglycans (PGN) to restrict inflammation, while others signal to host toll and imd pathways to induce genes of innate immunity and antimicrobial peptides (AMP). Mammalian PGLYRP1, - 3 and -4 are bactericidal against gram positive and negative bacteria, and PGLYRP2 is an amidase. In vitro, they work synergistically with AMPs, synergy in vivo is not known, but suspected. Whether the mammalian PGLYRPs also modulate innate immune signals remains to be fully investigated.. Thus, the mammalian PGLYRPs may represent a new class of antimicrobial immune modulators in the cornea. Our central hypothesis in this R21 proposal is that PGLYRPs in the mammalian cornea may have a dual role in deterring pathogenic bacterial infections while promoting innate immune signals for corneal healing and homeostasis. Two aims will test this central hypothesis.1) Test antibacterial defense capabilities of Pglyrp1-4 null mice in a Pseudomonas (P).aeruginosa keratitis model. 2a)Test if the PGLYRPs cross talk with innate immune signals (TLR2, 4 and Nod2) in the cornea to up regulate cytokines and b- defensins, and 2b) whether the PGLYRPs expedite corneal healing by promoting epithelial migration. This exploratory study of the PGLYRP family will provide the necessary assessment of its role in the cornea and the groundwork for future detailed studies of each member in promoting corneal health, curbing infections and developing targeted therapies. In the future our study may lead to prophylactic or therapeutic approaches that tweak PGLYRP levels in the corneal epithelium before/after surgery, infection and storage of transplant corneas. PUBLIC HEALTH RELEVANCE: Our findings on this peptidoglycan recognition protein family will elucidate natural antimicrobial defense mechanisms in the cornea, therapeutic/prophylactic strategies for regulating their levels and functions during corneal infections and injury or surgery-related trauma, transplant cornea or contact lens storage.

描述（由申请人提供）：角膜是眼睛的透明、折射、保护性粘膜屏障。角膜感染对健康视力构成严重威胁。感染的风险随着受伤、手术、日常佩戴隐形眼镜和年龄的增加而增加。抗菌蛋白和肽的研究对于阐明角膜的天然保护机制和基于这些机制的治疗至关重要。我们的提案重点关注哺乳动物肽聚糖识别蛋白（PGLYRP）家族的四种抗菌蛋白，它们存在于各种粘膜屏障中，并于十多年前被识别。我们在人类和小鼠角膜中发现了 PGLYRP1，随后还发现了其他 PGLYRP2、-3 和 -4。哺乳动物 PGLYRP 成员的功能通常尚未得到充分研究，尤其是对眼睛中的这些功能知之甚少。人们对昆虫中的大 PGLYRP 家族了解更多：它们大多具有杀菌作用，一些水解肽聚糖 (PGN) 以限制炎症，而另一些则向宿主 toll 和 imd 途径发出信号，以诱导先天免疫和抗菌肽 (AMP) 基因。哺乳动物PGLYRP1、-3和-4对革兰氏阳性菌和阴性菌具有杀菌作用，PGLYRP2是一种酰胺酶。在体外，它们与 AMP 协同作用，体内协同作用尚不清楚，但值得怀疑。哺乳动物PGLYRP是否也调节先天免疫信号仍有待充分研究。因此，哺乳动物PGLYRP可能代表角膜中一类新的抗菌免疫调节剂。我们在 R21 提案中的中心假设是，哺乳动物角膜中的 PGLYRP 可能具有双重作用，既可以阻止病原细菌感染，又可以促进角膜愈合和体内平衡的先天免疫信号。有两个目标将检验这一中心假设。1) 在铜绿假单胞菌 (P).铜绿假单胞菌角膜炎模型中测试 Pglyrp1-4 缺失小鼠的抗菌防御能力。 2a) 测试 PGLYRP 是否与角膜中的先天免疫信号（TLR2、4 和 Nod2）相互作用以上调细胞因子和 β-防御素，以及 2b) PGLYRP 是否通过促进上皮迁移来加速角膜愈合。这项针对 PGLYRP 家族的探索性研究将为其在角膜中的作用提供必要的评估，并为未来对每个成员在促进角膜健康、控制感染和开发靶向治疗方面的详细研究奠定基础。未来，我们的研究可能会带来预防或治疗方法，在手术、感染和移植角膜保存之前/之后调整角膜上皮中的 PGLYRP 水平。 公共健康相关性：我们对这个肽聚糖识别蛋白家族的研究结果将阐明角膜中的天然抗菌防御机制，以及在角膜感染和损伤或手术相关创伤、移植角膜或隐形眼镜储存期间调节其水平和功能的治疗/预防策略。