The present invention relates to a pharmaceutical composition for treating liver diseases, comprising a miRNA mimic comprising a single strand RNA molecule of hsa-miR-21-3p (SEQ ID No: 35). The miRNA mimic of the present invention can be used to treat liver diseases through regulating the expression of methionine adenosyltransferase 2A and 2B (MAT2A and MAT2B), acetyl-CoA carboxylase 1 and 2 (ACACA and ACACB), diglyceride acyltransferase 2 (DGAT2), and so on. In addition, the present invention also relates to a method for reducing the expression of the above-mentioned enzymes.本發明係關於一種用以治療肝臟疾病之醫藥組成物，其包含一包含hsa-miR-21-3p(SEQ ID No：35)之單股RNA分子的微小RNA模擬物。前述微小RNA模擬物係藉由調控甲硫胺酸腺苷轉移酶MAT2A及MAT2B、乙醯輔酶A羧化酶ACACA及ACACB，以及二脂醯甘油醯基轉移酶DGAT2等基因的表現，而達到治療肝臟疾病的效果。此外，本發明亦關於一種降低前述酶表現之方法。
