Characterization and Function Analysis of miRNA Editing during Fat Deposition in Chinese Indigenous Ningxiang Pigs.

Simple Summary: In order to gain insight into the molecular mechanism of porcine fat deposition, this study reported, for the first time, miRNA editing in the adipose tissue of Ningxiang pigs. We performed bioinformatics analyses, such as developmental stage-specific site screening, target gene prediction, and functional enrichment analysis, to obtain the functional miRNA editing sites associated with fat deposition; we found that miR-497 editing might inhibit fat deposition in pigs through retargeting genes. These findings not only enhance our understanding of the functional roles and mechanisms of miRNA editing in adipose development but also hold significant importance for improving the lean meat percentage of Ningxiang pigs and promoting their industrial development. This study aimed to identify active miRNA editing sites during adipose development in Ningxiang pigs and analyze their characteristics and functions. Based on small RNA-seq data from the subcutaneous adipose tissues of Ningxiang pigs at four stages—30 days (piglet), 90 days (nursery), 150 days (early fattening), and 210 days (late fattening)—we constructed a developmental map of miRNA editing in the adipose tissues of Ningxiang pigs. A total of 505 miRNA editing sites were identified using the revised pipeline, with C-to-U editing types being the most prevalent, followed by U-to-C, A-to-G, and G-to-U. Importantly, these four types of miRNA editing exhibited base preferences. The number of editing sites showed obvious differences among age groups, with the highest occurrence of miRNA editing events observed at 90 days of age and the lowest at 150 days of age. A total of nine miRNA editing sites were identified in the miRNA seed region, with significant differences in editing levels (p < 0.05) located in ssc-miR-23a, ssc-miR-27a, ssc-miR-30b-5p, ssc-miR-15a, ssc-miR-497, ssc-miR-15b, and ssc-miR-425-5p, respectively. Target gene prediction and KEGG enrichment analyses indicated that the editing of miR-497 might potentially regulate fat deposition by inhibiting adipose synthesis via influencing target binding. These results provide new insights into the regulatory mechanism of pig fat deposition. [ABSTRACT FROM AUTHOR]