Cathepsins and osteonecrosis: analysis based on European samples from the FinnGen Database and IEU OpenGWAS Database

doi:10.12307/2025.726

Abstract

Abstract: BACKGROUND: Osteonecrosis is an orthopedic disease that severely limits joint function, with complex pathogenesis involving multiple risk factors. Cathepsins, as a class of enzymes that play a key role in bone metabolism, are closely related to the proliferation, differentiation of bone cells, and remodeling of the bone matrix. However, previous studies have mostly focused on descriptive analyses, lacking direct evidence of causal relationships.
OBJECTIVE: To clarify the potential causal relationship between cathepsins and osteonecrosis and to explore their possible mechanisms by analyzing large-scale sample data from the FinnGen database.
METHODS: We obtained osteonecrosis-related data from the FinnGen database, including R9 (a total of 359 399 samples: 1 385 cases and 358 014 controls) and R10 versions (a total of 392 580 samples: 1 543 cases and 391 037 controls). Single nucleotide polymorphisms associated with nine cathepsins (cathepsin B, E, F, G, H, O, S, L2, and Z) were acquired from a previous study (3 301 individuals). Univariate Mendelian randomization, reverse univariate Mendelian randomization, and multivariate Mendelian randomization analyses were conducted using the inverse variance weighted method, MR-Egger method, weighted median method, simple mode method, and weighted mode method. Initially, Mendelian randomization analysis was performed using osteonecrosis data from R9. Additionally, sensitivity analyses were conducted using Cochran’s Q test, MR-Egger intercept, MR-PRESSO global test, and leave-one-out analysis to check for horizontal pleiotropy and heterogeneity. Subsequently, a validation analysis study was carried out on the R10 dataset, and a meta-analysis was conducted to combine the two datasets to explore the joint effect.
RESULTS AND CONCLUSION: Univariate Mendelian randomization analysis results showed that higher levels of cathepsin B were significantly associated with a reduced risk of osteonecrosis (inverse variance weighted: odds ratio (OR)=0.865, 95% confidence interval (CI): 0.762-0.982, P=0.025), and no reverse causal relationship was found between the nine cathepsins and osteonecrosis (P > 0.05). These associations were validated by meta-analysis. Multivariate analysis, using the nine cathepsins as covariates, revealed a reverse causal relationship between the levels of cathepsin B and the risk of osteonecrosis (inverse variance weighted: OR=0.8710, 95% CI: 0.761-0.997, P=0.045), consistent with the results before adjustment. Sensitivity analyses based on heterogeneity and horizontal pleiotropy suggested that the results were relatively robust. This study suggests that there is a causal relationship between high levels of cathepsin B and the reduced risk of osteonecrosis, and it may serve as a biomarker for osteonecrosis, providing new directions and insights for the diagnosis and treatment of osteonecrosis. Although this study is based on data analysis of European populations, these findings have important implications for Chinese biomedical research, especially in understanding disease mechanisms, developing biomarkers, and formulating treatment strategies. They also encourage similar studies conducted on Chinese populations to explore the impact of racial and genetic background differences on the occurrence of osteonecrosis.

中国组织工程研究杂志出版内容重点：组织构建；骨细胞；软骨细胞；细胞培养；成纤维细胞；血管内皮细胞；骨质疏松；组织工程

Key words: osteonecrosis, cathepsins, Mendelian randomization, multivariate, causal relationship, single nucleotide polymorphisms, instrumental variables, genome-wide association studies, inverse variance weighted method, Meta-analysis

CLC Number:

Chai Jinlian, Sun Tiefeng, Li Wei, Zhang Bochun, Li Guangzheng, Shao Xuekun, Wang Ping, Liang Xuezhen. Cathepsins and osteonecrosis: analysis based on European samples from the FinnGen Database and IEU OpenGWAS Database[J]. Chinese Journal of Tissue Engineering Research, 2025, 29(24): 5254-5262.

Figures/Tables 4

2.1 正向单变量孟德尔随机化分析结果根据选择标准，纳入了9种组织蛋白酶(B，E，F，G，H，L2，O，S，Z)的工具变量，选取P < 5×10-6的SNP，排除LD中的SNP后，从每种组织蛋白酶的GWAS数据中提取出9-23个SNP作为工具变量，共计117个SNP。计算每个SNP的F统计量，所有SNP的最小F值为20.798。每个工具变量的F统计量大于10，没有SNP被排除为弱工具变量，表明弱工具变量偏倚的证据较低。此外，通过Phenoscanner V2数据库未发现可能影响暴露与结局之间关系的SNP。单变量孟德尔随机化分析9种组织蛋白酶(组织蛋白酶B，E，F，G，H，O，S，L2，Z)对骨坏死的影响。高水平的组织蛋白酶 S与骨坏死的发病风险增加存在显著的因果关系(逆方差加权：P=0.045，OR=1.125，95%CI：1.003-1.261)。而高水平的组织蛋白酶B (逆方差加权：P=0.025，OR=0.865，95%CI：0.762-0.982)和高水平的组织蛋白酶Z(逆方差加权：P=0.042，OR=0.882，95%CI：0.780-0.996)与骨坏死的发生风险降低相关。对于组织蛋白酶E，F，G，H，O，L2，逆方差加权法与骨坏死发病风险无明显相关性(P > 0.05)，比值比接近于0，提示其他类型组织蛋白酶与骨坏死转归无明显因果关系。Cochran’s Q、MR-Egger截距和MR-PRESSO全局检验未发现任何异质性或水平多效性的证据(P > 0.05)。在留一法分析中，没有SNP显著破坏组织蛋白酶S对骨坏死的总体影响；漏斗图的对称性也表明无多效性。上述分析的结果证明了研究结果的稳定性。单变量孟德尔随机化的显著性估计值以森林图的形式在图1中进行了描述，异质性和多效性检验结果见表2。 2.2 反向单变量孟德尔随机化分析结果为了验证骨坏死对9种组织蛋白酶(B，E，F，G，H，O，S，L2和Z)是否具有反向调控作用，文章进行了反向单变量孟德尔随机化分析。以R9水平的骨坏死作为暴露量，以9种组织蛋白酶作为结局。选择P值小于5×10-6的SNPs并去除LD中的SNPs后，每个骨坏死使用10个SNPs作为工具变量。计算每个SNP的F统计量，所有SNP的最小F值为20.854。每个工具变量的F统计量大于10，表明弱工具变量偏倚的低证据，没有SNP被排除为弱工具变量。此外，通过Phennscanner V2数据库未发现可能影响暴露和结局之间关系的 SNP。反向单变量孟德尔随机化分析结果未发现骨坏死和9种组织蛋白酶之间存在任何反向因果关系(P > 0.05)，除组织蛋白酶G和组织蛋白酶O的Cochran’s Q_P值小于0.05，提示可能存在一定程度的异质性；留一法分析中排除每个SNP后对估计值未见明显影响；使用MR-Egger截距分析均未发现水平多效性的证据(P > 0.05)，表明上述分析结果的稳健性。反向单变量孟德尔随机化的显著性估计值以森林图的形式呈现在图2中，异质性和多效性检验结果见表3。 2.3 多变量孟德尔随机化分析结果在校正其他类型的组织蛋白酶后，进行了多变量孟德尔随机化分析，以验证单变量分析中获得的无偏估计。在多变量孟德尔随机化分析中，评估了不同的组织蛋白酶暴露对骨坏死的影响。经过严格的选择阈值(P=5×10-6， R2=0.001，kb=10 000)后，随后的重复数据删除、聚类和协调程序最终确定了94个SNP为用于多变量孟德尔随机化分析的工具变量。结果显示，在校正其他类型组织蛋白酶后，组织蛋白酶B与骨坏死发生风险呈显著负相关(逆方差加权：P=0.045，OR=0.871，95%CI：0.761 2-0.997)，提示其可能对骨坏死具有保护作用；而组织蛋白酶S (逆方差加权：P=0.056，OR=1.128，95%CI：0.997-1.275)和组织蛋白酶Z (逆方差加权：P=0.627，OR=0.961，95%CI：0.819-1.128)水平与骨坏死风险的因果关系在多变量孟德尔随机化分析中不存在。其他组织蛋白酶(F、G、H、O和L2)也与骨坏死无显著相关性，P值超过显著性阈值。Cochran’s Q检验结果显示无异质性证据(P=0.223)，MR-Egger截距检验未提示存在水平多效性(P=0.218)。多变量孟德尔随机化的估计值以图3中森林图的形式表示。 2.4 验证分析与Meta分析结果为了进一步验证文章结论的稳定性和可靠性，在R10水平上重新分析了FinnGen数据库的骨坏死 GWAS数据。结果显示，组织蛋白酶S水平升高与骨坏死发病风险增加存在显著的因果关系(逆方差加权：P=0.005，OR=1.161，95%CI：1.046-1.288)。单变量孟德尔随机化的显著估计值以图4中森林图的形式呈现。随后进行孟德尔随机化分析，将两种分析的结果合并为Meta分析。Meta分析一致表明，组织蛋白酶B和组织蛋白酶Z对骨坏死的发生具有保护作用，而组织蛋白酶 S与骨坏死发生风险增加相关，这与文章之前的孟德尔随机化分析结果一致，如图5所示。 "

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