PLOD2突变导致Bruck综合征机制及骨髓移植治疗疗效研究

Bruck syndrome is an extremely rare autosomal recessive osteogenesis imperfect, which is mainly characterized by congenital joint contracture, and increased bone fragility leading to repeated fractures in newborns or early childhood. The PLOD2 mutation is one of the causative genes of Bruck syndrome. PLOD2 causes Bruck syndrome mainly by affecting collagen cross-linking, but the specific mechanism is not fully understood. By constructing the PLOD2 c.503-2A>G mutant mouse model, using bone histometry, bone biomechanics, quantitative CT and other evaluation methods, the mechanism of Bruck syndrome caused by POLD2 mutation was studied from genes, RNAs, proteins, signaling pathways and bone cell comprehensively. The treatment of Bruck syndrome is very scarce. By evaluating the effects of bone marrow transplantation on bone mineral density, bone strength, bone microstructure, collagen and signaling pathway, a new protocol for the treatment of Bruck syndrome can be obtained hopefully, which is of importance for the treatment of severe type of osteogenesis imperfecta.

Bruck综合征是一种极其罕见的常染色体隐性遗传性成骨不全症，主要表现为先天性的关节挛缩，骨脆性增加导致新生儿或幼儿早期即可发生反复骨折。PLOD2是Bruck综合征的致病基因之一。PLOD2主要通过影响胶原交联导致Bruck综合征，但具体机制尚不十分清楚。通过构建PLOD2 c.503-2A＞G突变小鼠模型，结合骨组织计量学、骨生物力学、定量CT检查等评估手段，从基因、RNA及蛋白质、信号通路、骨细胞等多个层面全面细致地揭示PLOD2导致Bruck综合征的发病机制。Bruck综合征的治疗非常匮乏，评价骨髓移植对PLOD2突变小鼠的骨密度、骨强度、骨骼微结构、胶原蛋白和信号通路的影响，获取Bruck综合征治疗的新方案，对开展重型成骨不全症治疗有重要意义。

成骨不全症是最常见的单基因遗传性骨病，新生儿发病率为1/10000-20000，主要临床表现包括骨骼脆性增高、反复骨折、骨骼畸形和身材矮小，骨骼外表现包括蓝灰色巩膜、牙本质发育不全、听力异常和关节韧带松弛等。Bruck综合征是一种极其罕见的常染色体隐性遗传性成骨不全症。该病主要表现为先天性关节挛缩，骨脆性增加，导致新生儿或幼儿早期即可发生反复骨折。FKBP10和 PLOD2分别编码FKBP65蛋白和赖氨酰羟化酶2，均是Bruck综合征的致病基因。其中PLOD2突变导致的Bruck综合征更为罕见。然而，PLOD2如何导致骨骼脆性增加和关节挛缩的机制尚不清楚。本研究旨在建立PLOD2 c.503-2A＞G导致 Bruck综合征的小鼠动物模型，探索PLOD2导致骨骼脆性增加和关节挛缩的机制。.本课题采用CRISPR/Cas9技术对PLOD2进行修饰，有野生型小鼠及PLOD2 c.503-2A＞G杂合小鼠出生，但是无纯合小鼠出生，考虑PLOD2突变导致纯合小鼠胚胎期死亡可能性比较大。比较8周龄杂合雄性小鼠和野生型小鼠的骨骼力学特点、骨骼微结构、骨骼HE染色和天狼星红染色，发现杂合小鼠和野生型小鼠的三点弯曲试验评估骨骼力学特点无明显差异，利用microCT评估骨骼微结构无明显差异。利用体外受精技术，获得E9.5、E10.5、E11.5纯合、杂合、野生型小鼠胚胎，发现纯合胚胎的器官发育延迟，局部炎症细胞增多，E12.5纯合小鼠胚胎死亡。.在课题资助下作为第一作者，共发表课题相关 SCI 收录论文6篇，中文疑难病例1篇。