Autophagy targeting nanoparticles in rheumatoid arthritis and osteoarthritis

Nanotechnology has been proven to be effective several times in the treatment of various diseases. Nanomedicine is a growing field of research for the development of novel drug delivery systems. Targeting autophagy with the help of nanotechnology based drug delivery might be beneficial over conventional ways. Autophagy is a degenerative process involving multiple steps to recycle essential components of cells, that goes into the senescence phase. It has a prominent role in pathogenesis as well as the homeostasis of cells involved in rheumatoid arthritis (RA) and osteoarthritis (OA). The health of chondrocytes is maintained by autophagy and dysregulation of autophagy is a major contributing factor in the death of chondrocytes. The autoimmune response to chondrocytes and synovium is a major trigger that ultimately leads to apoptosis of cells and then autophagy. Chondrocytes are stimulated by IL-17, IL-1 and INF-alpha to secrete cartilage degrading metalloproteinases. Unhealthy conditions of cartilage reduce the number of chondrocytes and layers of articular cartilage, resulting in severe pain due to the movement of joints involving friction. Autophagy plays a major role in osteoclastogenesis in RA. The death of chondrocytes is a major hallmark of OA progression that involves bone degradation due to the complete removal of the cartilage layer. There are reports entailing that the inhibition of autophagy might be protective and can reduce bone erosion and osteoclast formation. In this review, we discussed the role of autophagy in OA and RA including signaling molecules, current therapies and nanotechnological advancements in treating these diseases.