MicroRNAs involved in innate immunity regulation in the sea cucumber: A review

The sea cucumber is one of the most economically significant echinoderms. The immunity against exogenous stimulation of sea cucumber is of great academic and economic importance. MicroRNAs (miRNAs) are a class of short endogenous non-coding RNAs (ncRNAs) that are considered as vital regulators of both innate and adaptive immune responses in most eukaryotes. In sea cucumbers, some miRNAs (such as miR-133, miR-137, and miR-2008, among others) that participate in the regulation of innate immunity have been recently identified and characterized. This review focuses on those known miRNAs and their corresponding target genes that participate in the regulation of the complement system, Toll-like receptor (TLR) pathway, reactive oxygen species (ROS) production and apoptosis pathways in sea cucumbers. Moreover, we cover immune-related miRNA investigations in sea cucumbers that provide insights into developing more miRNA-based biomarkers and therapeutic strategies for sea cucumber diseases.