Identification and Characterization of Osmoregulation Related MicroRNAs in Gills of Hybrid Tilapia Under Three Types of Osmotic Stress

Abstract

Researchers have increasingly suggested that microRNAs (miRNAs) are small non-coding RNAs that post-transcriptionally regulate gene expression and protein translation in organs and respond to abiotic and biotic stressors. To understand the function of miRNAs in osmotic stress regulation of the gills of hybrid tilapia (Oreochromis mossambicus ♀ × Oreochromis urolepis hornorum ♂), high-throughput Illumina deep sequencing technology was used to investigate the expression profiles of miRNAs under salinity stress (S, 25‰), alkalinity stress (A, 4‰) and salinity–alkalinity stress (SA, S: 15‰, A: 4‰) challenges. The results showed that 31, 41, and 27 upregulated and 33, 42, and 40 downregulated miRNAs (P < 0.05) were identified in the salt stress, alkali stress, and saline–alkali stress group, respectively, which were compared with those in the control group (C). Fourteen significantly differently expressed miRNAs were selected randomly and then validated by a quantitative polymerase chain reaction. On the basis of Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway analysis, genes related to osmoregulation and biosynthesis were enriched in the three types of osmotic stress. In addition, three miRNAs and three predicted target genes were chosen to conduct a quantitative polymerase chain reaction in the hybrid tilapia and its parents during 96-h osmotic stress. Differential expression patterns of miRNAs provided the basis for research data to further investigate the miRNA-modulating networks in osmoregulation of teleost.

The Discovery and Characterization of Conserved and Novel miRNAs in the Different Developmental Stages and Organs of Pikeperch (Sander lucioperca)

“…The abundance of the three most highly expressed mature miRs in the gills (slu-mir-205-5p, slu-mir-203b-3p, and slu-mir-725-3p) was up to 440-fold higher compared to the expression levels in the other organs ( Table 2 ). This organ-specific enrichment is consistent with the findings of many other studies on teleosts and mammals [ 21 , 22 , 29 , 69 , 95 ]. The DE of the dominant 5p-arm of slu-mir-205-5p in the gills, as well as slu-mir-122 in the liver, was also confirmed by qPCR ( Figure 3 ).…”

“…Slu-mir-205-5p is highly abundant only in gills. This gill-specific enrichment is also conserved in other fish species [22,29,71]. However, its function in gills is not well known.…”

“…Similarly, investigations of the miRNAs associated with smoltification and sea water adaptation in salmonids have revealed groups of miRNAs targeting genes enriched in particular stress and immune response pathways [ 15 , 18 ]. Other studies on teleost fishes like tilapia and zebrafish have identified miRNAs associated with osmoregulatory stress and hypoxia [ 29 , 30 ]. Economically interesting traits like growth are likely regulated in fish by particular miRNAs, as indicated in studies on Nile tilapia [ 18 , 19 ].…”

Characterization of miRNAs in Embryonic, Larval, and Adult Lumpfish Provides a Reference miRNAome for Cyclopterus lumpus

“…RT-qPCR results confirmed the enrichment of clu-miR-203-3p, clu-miR-203a-5p, and clu-miR-205-1-5p. Some of these miRNAs, such as miR-200, miR-205, and miR-375, were enriched in cod gill as well [ 20 ], while miR-200, miR-203, and miR-205 were enriched in gills of tilapia [ 80 ]. One of these miRNAs, miR-200, has been shown as important to gill function in cell studies of fish [ 81 ].…”