MicroRNAs and their role in heart transplantation insights into rejection mechanisms: A narrative review

Figures

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  Figure 1. Biogenesis of microRNAs (miRNAs). The process begins in the nucleus, where miRNA genes are transcribed by RNA polymerase II (or III) into primary miRNAs (pri-miRNAs). These pri-miRNAs are processed by the microprocessor complex, consisting of Drosha and DGCR8, into precursor miRNAs (pre-miRNAs), which are then exported to the cytoplasm by Exportin-5. In the cytoplasm, the enzyme Dicer further processes pre-miRNAs into mature miRNA duplexes. One strand of the miRNA duplex is incorporated into the Argonaute-containing RISC, while the other strand is degraded. The mature miRNA then guides RISC to target mRNA, leading to translational repression or mRNA degradation. Key proteins and cellular compartments involved in each step are indicated.

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  Figure 2. Timeline of miRNAs associated with (A) favorable and (B) unfavorable/ambiguos prognosis.