Li Kai, Li Shijue, Zhang Haojie, Lei Di, Lo Wai Leung Ambrose, Ding Minghui
Department of Rehabilitation Medicine, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, China.
Front Mol Neurosci. 2022 Apr 21;15:846554. doi: 10.3389/fnmol.2022.846554. eCollection 2022.
Lumbar disc herniation (LDH) is a musculoskeletal disease that contributes to low back pain, sciatica, and movement disorder. Existing studies have suggested that the immune environment factors are the primary contributions to LDH. However, its etiology remains unknown. We sought to identify the potential diagnostic biomarkers and analyze the immune infiltration pattern in LDH.
The whole-blood gene expression level profiles of GSE124272 and GSE150408 were downloaded from the Gene Expression Omnibus (GEO) database, including that of 25 patients with LDH and 25 healthy volunteers. After merging the two microarray datasets, Differentially Expressed Genes (DEGs) were screened, and a functional correlation analysis was performed. The Least Absolute Shrinkage and Selection Operator (LASSO) logistic regression algorithm and support vector machine recursive feature elimination (SVM-RFE) were applied to identify diagnostic biomarkers by a cross-validation method. Then, the GSE42611 dataset was used as a validation dataset to detect the expression level of these diagnostic biomarkers in the nucleus pulposus and evaluate their accuracy. The hub genes in the network were identified by the CIBERSORT tool and the Weighted Gene Coexpression Network Analysis (WGCNA). A Spearman correlation analysis between diagnostic markers and infiltrating immune cells was conducted to further illustrate the molecular immune mechanism of LDH.
The azurophil granule and the systemic lupus erythematosus pathway were significantly different between the healthy group and the LDH group after gene enrichment analysis. The XLOC_l2_012836, lnc-FGD3-1, and scavenger receptor class A member 5 were correlated with the immune cell infiltration in various degrees. In addition, five hub genes that correlated with LDH were identified, including AQP9, SIRPB2, SLC16A3, LILRB3, and HSPA6.
The XLOC_l2_012836, lnc-FGD3-1, and SCARA5 might be adopted for the early diagnosis of LDH. The five identified hub genes might have similar pathological mechanisms that contribute to the degeneration of the lumbar disc. The identified hub genes and immune infiltrating pattern extend the knowledge on the potential functioning mechanisms, which offer guidance for the development of therapeutic targets of LDH.
腰椎间盘突出症（LDH）是一种导致腰痛、坐骨神经痛和运动障碍的肌肉骨骼疾病。现有研究表明免疫环境因素是LDH的主要成因。然而，其病因仍不明。我们试图识别潜在的诊断生物标志物并分析LDH中的免疫浸润模式。
从基因表达综合数据库（GEO）下载GSE124272和GSE150408的全血基因表达水平谱，包括25例LDH患者和25名健康志愿者的谱。合并两个微阵列数据集后，筛选差异表达基因（DEG）并进行功能相关性分析。应用最小绝对收缩和选择算子（LASSO）逻辑回归算法和支持向量机递归特征消除（SVM-RFE）通过交叉验证方法识别诊断生物标志物。然后，将GSE42611数据集用作验证数据集，以检测这些诊断生物标志物在髓核中的表达水平并评估其准确性。通过CIBERSORT工具和加权基因共表达网络分析（WGCNA）识别网络中的枢纽基因。对诊断标志物与浸润性免疫细胞进行Spearman相关性分析，以进一步阐明LDH的分子免疫机制。
基因富集分析后，嗜天青颗粒和系统性红斑狼疮途径在健康组和LDH组之间存在显著差异。XLOC_l2_012836、lnc-FGD3-1和清道夫受体A类成员5与免疫细胞浸润有不同程度的相关性。此外，鉴定出五个与LDH相关的枢纽基因，包括水通道蛋白9（AQP9）、信号调节蛋白β2（SIRPB2）、溶质载体家族16成员3（SLC16A3）、白细胞免疫球蛋白样受体亚家族B成员3（LILRB3）和热休克蛋白家族A成员6（HSPA6）。
XLOC_l2_012836、lnc-FGD3-1和清道夫受体A类成员5（SCARA5）可能用于LDH的早期诊断。鉴定出的五个枢纽基因可能具有相似的病理机制，导致腰椎间盘退变。鉴定出的枢纽基因和免疫浸润模式扩展了对潜在功能机制的认识，为LDH治疗靶点的开发提供了指导。
