Roles of autophagy in rheumatoid arthritis

Autophagy, a vital mechanism restricted in tissues, exerts its cytoprotective role through the degradation mechanism of damaged or aging organelles, harmful protein aggregates and intracellular pathogens, followed by energy furnishment. However, dysfunctional autophagy is associated with the development of autoimmune diseases such as rheumatoid arthritis (RA). In pathological conditions, autophagy may be involved in the maturation, survival and proliferation of various immune and non-immune cells and plays a key role in the pathogenesis of RA. Furthermore, autophagy appears to be involved in the citrullination of T lymphocytes and the presentation of citrullinated peptides, which are presented to T lymphocytes via the major histocompatibility complex, causing immune responses and chronic inflammation, as well as bone and cartilage destruction associated with apoptosis resistance of RA fibroblast-like synoviocyte (RAFLS) and osteoclastogenesis. In this review, we have summarised the roles of autophagy in the pathogenesis of RA including citrullination, immune tolerance break, osteoclastogenesis, RA FLS cell dysplasia, apoptosis resistance, together with the therapeutic potentials of autophagy regulators.