Versatile roles for neutrophil proteinase 3 in hematopoiesis and inflammation.

Neutrophil proteinase 3 (PR3), cathepsin G, elastase, and neutrophil serine protease 4 constitute the neutrophil serine protease family. These four members share varying sequence homology and functional similarities with each other. However, PR3 stands out as a unique autoantigen, serving as a primary autoantigen in anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis. Numerous studies have documented or reviewed the molecular pathogenesis or diagnostic utility of PR3 in ANCA-associated vasculitis. Nevertheless, the role of PR3 in other areas, particularly within the hematopoietic system, appears to have been overlooked. Indeed, beyond its involvement in vasculitis, PR3 contributes to cell apoptosis, hematopoietic abnormalities, diabetic ketoacidosis, and various other inflammatory diseases. In this study, we aim to summarize the research on the function of neutrophil PR3 in hematopoiesis and to elucidate its potential role in neutrophil aging and inflammatory diseases.