CLOCK and rheumatoid arthritis: Prior studies have indicated that regulation of inflammation is attained through the core components of circadian clock such as Clock, Rev-erbα and Cry1/2, accounting for diurnal rhythmicity in the severity (symptom) of inflammatory diseases (e.g., colitis and rheumatoid arthritis) and increased susceptibility to inflammation-related diseases (e.g., obesity and NAFLD) 54-59.