Screening of lncRNA Profiles During Intramuscular Adipogenic Differentiation Inlongissimus Dorsi and Semitendinosus Muscles in Pigs

Background: Intramuscular fat content is an important factor that determines meat quality in pigs. In recent years, epigenetic regulation has increasingly studied the physiological model of intramuscular fat. Although long non-coding RNAs play essential roles in various biological processes, their role in intramuscular fat deposition in pigs remains largely unknown. Results: In this study, intramuscular preadipocytes in the longissimus dorsi and semitendinosus of Large White pigs were isolated and induced into adipogenic differentiation in vitro. High-throughput RNA-seq was then carried out to estimate the expression of lncRNAs at 0, 2, and 8 days post-differentiation. At this stage, 2135 lncRNAs, including 575 novel lncRNAs, were identified. lncRNAs are shorter, less expressed, and less conserved RNAs than protein-coding mRNAs. KEGG analysis showed that the differentially expressed lncRNAs were more common in pathways that are closely involved with adipogenesis and lipid metabolism. Of these, lnc_000368, a previously undescribed lncRNA, was found to gradually increase during the adipogenic process. qRT-PCR and a western blot revealed that the knockdown of lnc_000368 by siRNA significantly repressed the expression of adipogenic genes (PPARγ, aP2, CEBPβ) and lipolytic genes (ATGL and HSL). As a result, lipid accumulation in porcine intramuscular adipocytes was impaired by the silencing of lnc_000368, as indicated by Oil Red O staining. Conclusions: Overall, our study identified a genome-wide lncRNA profile related to porcine intramuscular fat deposition, and the results suggest that lnc_000368 is a potential target gene that might be targeted in pig breeding in the future.