Fig. 1

Biogenesis of miRNAs and Cholesterol Control. In a nutshell, miRNAs are first transcribed by RNA polymerase II (RNAP II), which then produces an initial transcript known as produced precursor miRNAs (pri-miRNA) [22, 23]. Following transcription, the common hairpin-loop secondary structure seen in pri-miRNAs is recognized and cleaved by the microprocessor complex (created by DGCR8 and Drosha). To create a double-stranded RNA, pre-miRNAs are transferred to the cytoplasm and then digested by the Dicer nuclease. The RNA-induced silencing complex (RISC), which utilizes the mature miRNA sequence to perform its regulatory role, is chosen through Ago2 [24,25,26]. Each miRNA may bind to a number of mRNAs involved in the transport, storage, utilization, and/or excretion of cholesterol as well as in its production, absorption, efflux, and other processes