Non-coding RNAs in schistosome reproductive maturation

In schistosomes, pathology and transmission are primarily driven by sustained egg deposition rather than by the mere presence of adult worms, and female reproductive competence is therefore regarded as a central issue in schistosome biology. Because the establishment and maintenance of female reproductive maturity require prolonged pairing with a male, this process is better understood as the establishment and maintenance of a pairing-dependent developmental state than as a simple morphological consequence of mating. Although this question has traditionally been addressed through protein-coding genes, signaling pathways, neural regulation and nutritional inputs, accumulating evidence suggests that non-coding RNAs (ncRNAs) may represent an additional and previously underappreciated regulatory layer. In this review, we re-examine schistosome miRNAs, lncRNAs and emerging ncRNA classes within a common framework relevant to pairing-dependent maturation. Among these, miRNAs currently provide the strongest evidence, progressing from cataloguing studies to functional analyses linking specific molecules to ovarian development, egg production, and conserved pathways such as Wnt. lncRNAs remain mechanistically less resolved, but recent life-cycle profiling, single-cell datasets, chromatin analyses, and perturbation experiments suggest roles in maintaining adult homeostasis and fertility. circRNAs and other emerging RNA layers remain largely exploratory, but they provide important additions to current views of schistosome maturation. Given the possibility that ncRNAs may be transferred between male and female worms, further investigation of ncRNA-mediated regulation could provide an important complement to current models of schistosome maturation and its maintenance.