MMP2 and systemic lupus erythematosus: Our newly developed NPs provide a general and useful tool for treating many other types of arthritis, since cartilage erosion and presence of MMP-2 are common features of degenerative and inflammatory joint diseases, such as rheumatoid arthritis [47], psoriatic arthritis [48], gouty arthritis [49], and systemic lupus erythematosus [50].