Erickson Christopher B, Hill Ryan, Pascablo Donna, Kazakia Galateia, Hansen Kirk, Bahney Chelsea
Department of Biochemistry and Molecular Genetics,University of Colorado, Anschutz Medical Campus, Aurora, CO.
Orthopaedic Trauma Institute, University of California, San Francisco (UCSF), San Francisco, CA.
J Life Sci (Westlake Village). 2021 Dec;3(4):1-30. doi: 10.36069/JoLS/20220601.
While most bones fully self-heal, certain diseases require bone allograft to assist with fracture healing. Bone allografts offer promise as treatments for such fractures due to their osteogenic properties. However, current bone allografts made of decellularized bone extracellular matrix (ECM) have high failure rates, and thus grafts which improve fracture healing outcomes are needed. Understanding specific changes to the ECM proteome during normal fracture healing would enable the identification of key proteins that could be used enhance osteogenicity of bone allograft. Here, we performed a timeseries analysis of the fracture callus in mice to investigate proteomic and mineralization changes to the ECM at key stages of fracture healing. We found that changes to the ECM proteome largely coincide with the distinct phases of fracture healing. Basement membrane proteins (AGRN, COL4, LAMA), cartilage proteins (COL2A1, ACAN), and collagen crosslinking enzymes (LOXL, PLOD, ITIH) were initially upregulated, followed by bone specific proteoglycans and collagens (IBSP, COL1A1). Various tissue proteases (MMP2, 9, 13, 14; CTSK, CTSG, ELANE) were expressed at different levels throughout fracture healing. These changes coordinated with mineralization of the fracture callus, which increased steeply during the initial stages of healing. Interestingly the later timepoint was characterized by a response to wound healing and high expression of clotting factors (F2, 7, 9, 10). We identified ELANE and ITIH2 as tissue remodeling enzymes having no prior known involvement with fracture healing. This data can be further mined to identify regenerative proteins for enhanced bone graft design.
虽然大多数骨骼能够完全自我愈合，但某些疾病需要同种异体骨移植来辅助骨折愈合。由于其成骨特性，同种异体骨移植有望成为此类骨折的治疗方法。然而，目前由脱细胞骨细胞外基质（ECM）制成的同种异体骨移植失败率很高，因此需要能够改善骨折愈合结果的移植材料。了解正常骨折愈合过程中ECM蛋白质组的特定变化，将有助于识别可用于增强同种异体骨成骨能力的关键蛋白质。在这里，我们对小鼠骨折痂进行了时间序列分析，以研究骨折愈合关键阶段ECM的蛋白质组学和矿化变化。我们发现，ECM蛋白质组的变化在很大程度上与骨折愈合的不同阶段相吻合。基底膜蛋白（AGRN、COL4、LAMA）、软骨蛋白（COL2A1、ACAN）和胶原交联酶（LOXL、PLOD、ITIH）最初上调，随后是骨特异性蛋白聚糖和胶原蛋白（IBSP、COL1A1）。各种组织蛋白酶（MMP2、9、13、14；CTSK、CTSG、ELANE）在整个骨折愈合过程中表达水平不同。这些变化与骨折痂的矿化相协调，在愈合初期矿化急剧增加。有趣的是，后期的特点是对伤口愈合的反应以及凝血因子（F2、7、9、10）的高表达。我们确定ELANE和ITIH2为组织重塑酶，此前未知它们与骨折愈合有关。这些数据可进一步挖掘，以识别用于改进骨移植设计的再生蛋白。
