The miR-8/miR-200 family: from functional diversification to translational applications

The miR-8/miR-200 family is a phylogenetically ancient microRNA regulator conserved across bilaterian animals, originating as a single miR-8 isoform in invertebrates and expanding to miR-200a/b/c, miR-141, and miR-429 in vertebrates through gene duplication. This review summarizes the biogenesis, genealogical details, and regulatory roles of the miR-8/miR-200 family. Furthermore, it presents the first comprehensive analysis of its evolutionary trajectory from invertebrates to vertebrates, thereby establishing a foundational understanding that underscores its significant potential for translational applications. Phylogenetic analyses confirm its sequence conservation and lineage-specific distribution, indicating that miR-8 originated in Platyhelminthes, with subsequent isoforms emerging in chordates. Functionally, this family plays pleiotropic roles: in invertebrates, miR-8 regulates immune defense, reproduction, and biosynthesis; in vertebrates, miR-200 subtypes modulate stress responses, epithelial-mesenchymal transition (EMT), tumor suppression, and neurodevelopment via conserved pathways (e.g., Wnt, Notch, PI3K). Cross-species conservation underlies core functions in cell differentiation, apoptosis, and growth, while vertebrate-specific adaptations drive roles in cancer (e.g., targeting ZEB1 in metastasis) and metabolic diseases (e.g., diabetes via β-cell apoptosis). This work explores the translational potential of this family, including nucleic acid pesticides in agriculture (targeting insect miR-8) and diagnostic/therapeutic tools in medicine (miR-200 as cancer biomarkers). Key challenges remain in delivery specificity and addressing functional pleiotropy. Future research should elucidate regulatory networks in non-model species and refine targeted delivery systems for clinical and agricultural applications.