Background

Traumatic Heterotopic Ossification (tHO) is one of complications of elbow fractures to the detriment of patients’ rehabilitation, and the severity of tHO corresponds to the size of ectopic bone. It has yet to be elucidated which proteins and pathways underlying the progression of tHO, and biomarkers to predict the severity of tHO at early stage of the disease also need further investigation.

Methods

In this study, a new rat model with distinct volume of ectopic bone was established first. Then a data-independent acquisition proteomics approach was used to investigate injured site tissues sequentially obtained from these rats (2, 7, 14, and 28 days post-injury). Differentially expressed analysis, functional annotation and co-expression analysis and protein–protein interaction network were performed to explore the pathways and hub proteins in the tHO progression. Clinical samples from a nest case–control study were used to validate the selected proteins for predicting the severity of tHO.

Results

The Achilles Tenotomy (AT) induced significantly larger sizes of ectopic bone compared to Partial Achilles Tenotomy (PAT) in rat models. A total of 3547 quantifiable proteins were screened for differential expression analysis among the AT, PAT and control groups. The hierarchical clustering and expression pattern analysis revealed more apparent difference in the pathways such as oxidative phosphorylation, mitochondrial function, and sirtuin signaling between AT and PAT group at the early stage (2 dpi) of tHO. The co-expression analysis identified five hub proteins, UBA1, EIF3E, RPL17, RPL27, and RPS28. qPCR assay, immunoblot assay and immunohistochemistry assay verified that these proteins had higher expression level in the tissue samples of clinically relevant HO patients and clinically irrelevant HO patients than HO negative patients.

Conclusion

The new established animal model and proteome profile could serve as a solid foundation for the comprehensive investigation of the progression of traumatic heterotopic ossification. And the identified 5 proteins (UBA1, EIF3E, RPL17, RPL27, and RPS28) may serve as potential biomarkers to predict the severity of tHO.

The translational potential of this article

The proteins identified in this study may be the potential biomarkers and therapeutic targets for predicting and treating the tHO at early stage.

中文翻译：

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比较蛋白质组学分析识别差异表达的蛋白质并揭示创伤性异位骨化进展的潜在机制

背景

创伤性异位骨化（tHO）是肘部骨折的并发症之一，不利于患者的康复，tHO的严重程度与异位骨的大小相对应。尚未阐明哪些蛋白质和途径是 tHO 进展的基础，并且在疾病早期预测 tHO 严重程度的生物标志物也需要进一步研究。

方法

本研究首先建立了具有明显异位骨体积的新型大鼠模型。然后使用与数据无关的采集蛋白质组学方法来研究从这些大鼠（受伤后 2、7、14 和 28 天）顺序获得的受伤部位组织。进行差异表达分析、功能注释和共表达分析以及蛋白质-蛋白质相互作用网络以探索 tHO 进展中的途径和中枢蛋白。巢病例对照研究的临床样本用于验证所选蛋白质以预测 tH2O 的严重程度。

结果

在大鼠模型中，与部分跟腱切断术 (PAT) 相比，跟腱切断术 (AT) 诱导的异位骨明显更大。共筛选了 3547 种可量化的蛋白质用于 AT、PAT 和对照组之间的差异表达分析。层次聚类和表达模式分析显示，在 tH2O 的早期（2 dpi），AT 和 PAT 组之间的氧化磷酸化、线粒体功能和 sirtuin 信号通路等途径存在更明显的差异。共表达分析确定了五种中枢蛋白，UBA1、EIF3E、RPL17、RPL27 和 RPS28。qPCR测定、免疫印迹测定和免疫组织化学测定证实，这些蛋白质在临床相关的HO患者和临床无关的HO患者的组织样本中的表达水平高于HO阴性患者。

结论

新建立的动物模型和蛋白质组谱可以作为全面研究创伤性异位骨化进展的坚实基础。鉴定出的 5 种蛋白质（UBA1、EIF3E、RPL17、RPL27 和 RPS28）可作为预测 tHO 严重程度的潜在生物标志物。

本文的翻译潜力

本研究中鉴定的蛋白质可能是早期预测和治疗 tH2O 的潜在生物标志物和治疗靶点。