哺乳动物固有免疫中肽聚糖识别蛋白研究进展

Research progress of peptidoglycan recognition proteins in mammalian innate immunity

肽聚糖识别蛋白（PGRPs或PGLYRPs）是重要的识别细菌肽聚糖的模式识别受体之一，且从昆虫到哺乳动物高度保守。哺乳动物有4个PGRPs，它们分别表达于不同的细胞／组织。PG—LYRP1、PGLYRP3和PGLYRP4具有抑杀细菌，而PGLYRP2水解肽聚糖的特性，最新研究表明PGLYRP2还具有促炎症的特性，其促炎症特性不依赖于其抗菌或水解肽聚糖的活动。血清和组织中PGLYRP2具有不同的功能，血清PGLYRP2可能具有清道夫功能，类似于昆虫PGRPs的酰胺酶活性，从而中和促炎症的肽聚糖；而组织中PGLYRP2参与炎症的诱导。PGRPs很可能在抗菌防御和炎症疾病中发挥作用，调节组织的局部炎症反应（如关节炎）；还与炎性疾病有关，例如银屑病。

Peptidoglycan recognition proteins （PGRPs or PGLYRPs）, a class of important pattern recognition receptors to recognize bacterial peptidoglycan （PGN）, are innate immunity proteins that are conserved from insects to mammals. Mammals have four PGRPs. These proteins are secreted proteins expressed in different ceils or tissues. In these PGRPs, PGLYRP1, PGLYRP3, and PGLYRP4 have antibacterial/bactericidal prop- erties; PGLYRP2 is PGN-hydrolytic. The latest researches indicated that PGLYRP2 has pro-inflammatory prop- erty that is independent of their hydrolytic and antibacterial activities. Furthermore, the PGLYRP2 in serum and in tissues may have different functions. Serum PGLYRP2 may have a scavenger function similar to amidase-ac- tivity of insect PGRPs. In comparison, PGLYRP2 in tissues participates in induction of inflammatory response. The PGRPs likely play a role both in antibacterial defenses and certain inflammatory diseases. They modulate local inflammatory responses in tissues, i.e. arthritic joints; and there is evidence showing the association of PGRPs with inflammatory diseases, such as psoriasis.