GRN and arthritic joint disease: The elevated expression of PGRN has been reported in inflammation‐related diseases or models, such as blood and adipose tissues in a mouse obesity model 14, cartilage of patients with arthritis as compared with normal controls 23, colons from inflammatory bowel‐diseased patients and a mouse colitis model 24 and gastric epithelial cells after infection with Helicobacter pylori25, 26.