PADI4 and Arthritis: Annotation of cell types in bone tissue (dataset: HU_0370_Bone_GSE169396) is shown in Fig. 2B. The breakdown of observational BGLAP (osteocalcin), IL-6, PADI4, and TNF-α expression levels revealed high expression of IL-6, TNF-α, and PADI4 in monocytes/macrophages, supporting their central role in driving inflammation and immune activation in arthritis.