N4-acetylcytidine (N4A) is an endogenous nucleoside metabolite from the degradation of tRNA. N4-Acetylcytidine is formed by N-acetyltransferase 10 and other enzymes. N4-acetylcytidine might sustain NLRP3 inflammasome activation via induction of HMGB1 expression and releasee. N4-Acetylcytidine modifies mRNA, tRNA and rRNA, affecting their stability, translation efficiency (such as enterovirus 71 RNA). N4-Acetylcytidine is used in the study of cancer, neuroinflammatory diseases, viral infections and obesity[1][2][3][4][5].