PTGS2 and rheumatoid arthritis: Moreover, cigarette smoke induces TH17 cells in the lymph node to package miR-132, which acts as a proinflammatory mediator by increasing osteoclastogenesis through the downregulation of cyclooxygenase-2 (COX2) in osteoclast precursor cells, thereby exacerbating RA [228], which exemplifies cross-organ communication.