COL6A1, LAPTM5, and ZFAND2A as Crucial Biomolecules Driving Immunoregulation in Human Nucleus Pulposus Degeneration

Intervertebral disc degeneration (IVDD) is a major contributor to chronic low back pain, driven by complex interactions among immune cells and various molecular mechanisms. In this study, we integrated single-cell RNA sequencing (scRNA-Seq), transcriptomics, and Mendelian randomization (MR) analysis to investigate the immune mechanisms and identify key biomolecules involved in IVDD. Single-cell analysis of nucleus pulposus (NP) samples from four patients with disc degeneration revealed 20 distinct clusters, which were categorized into four primary cell types: blood cells, chondrocytes, endothelial cells, and stromal cells. These cell types were shown to play crucial roles in the immune microenvironment, as evidenced by ligand-receptor interaction analysis, which delineated potential intercellular communication networks. By combining eQTL (expression Quantitative Trait Loci) data with FinnGen datasets in MR analysis, we identified five key genes (CD83, COL6A1, LAPTM5, NPC2, ZFAND2A) significantly associated with IVDD risk. The expression of these genes in NP tissues showed strong correlations with immune cell infiltration. Protein-level validation confirmed the upregulation of COL6A1, LAPTM5, and ZFAND2A in degenerative NP tissues. Functional enrichment analysis revealed their involvement in multiple immune-related pathways. Additionally, co-expression analysis identified relationships between these key genes and critical immune genes, such as CD14 and CD274. This study leverages multi-omics integration to uncover the immune regulatory mechanisms underlying IVDD, providing valuable insights into the role of biomolecules in the pathogenesis of disc degeneration and offering potential for novel diagnostic and therapeutic strategies.