Regulatory Mechanisms of miRNA Turnover: Insights into ZSWIM8-Mediated Target-Directed MicroRNA Degradation.

MicroRNAs (miRNAs), as an integral component of gene regulatory networks, play a critical role in post-transcriptional regulation, maintaining a dynamic balance between miRNA biogenesis and turnover essential for maintaining cellular homeostasis. The regulation of miRNA turnover, particularly through target-directed microRNA degradation (TDMD), is emerging as a key mechanism in gene expression control in response to physiological, developmental, and environmental changes. This process is mediated by the ubiquitin-proteasome system (UPS), where the E3 ligase ZSWIM8 functions as an adaptor to facilitate the recognition and degradation of Argonaute (AGO) proteins, essential components of the miRNA-induced silencing complex (miRISC), thus negatively regulating gene expression. The ZSWIM8-UPS axis contributes to the precise modulation of miRNA levels by targeting AGO proteins for degradation, thereby influencing miRNA stability and function. This review summarizes the mechanisms underlying ZSWIM8-mediated TDMD, its molecular interactions, and the potential therapeutic applications of targeting miRNA turnover pathways. By understanding the regulation of miRNA degradation, we aim to inform future strategies for the clinical manipulation of miRNA-based therapeutics.