miR-29a modulates SCD expression and is regulated in response to a saturated fatty acids diet in juvenile GIFT (Oreochromis niloticus)

Abstract

MicroRNAs (miRNAs) are small non-coding RNAs that regulate target gene expression by binding to the 3′ untranslated region (3′ UTR) of the target mRNA. MiRNAs regulate a large variety of genes, including those involved in liver biology and disease. Here, we report for the first time that miR-29a post-transcriptionally regulates stearoyl-CoA desaturase (SCD) by binding to its 3′ UTR in genetically improved farmed tilapia (GIFT), Oreochromis niloticus, as shown by a 3′ UTR luciferase reporter assay. miR-29a antagomir treatment in vivo resulted in significant upregulation of SCD expression. We found that miR-29a expression was negatively correlated with SCD expression in GIFT liver. Inhibition of miR-29a led to a significant increase in SCD expression on day 60 induced by a saturated fatty acid diet, thereby increasing conversion of 16:0 and 18:0 to 16:1 and 18:1, respectively, and activating serum insulin, which would favor glucose and lipid uptake by the liver. These results indicate that miR-29a regulates SCD levels by binding to its 3′ UTR, and this interaction affects saturated fatty acid stress induction and insulin and lipid accumulation in serum. Our results suggest that miR-29a is critical in regulating lipid metabolism homeostasis in GIFT liver, and this might provide a basis for understanding the biological processes and therapeutic intervention encountered in fatty liver.

MicroRNA-206 Regulation of Skin Pigmentation in Koi Carp (Cyprinus carpio L.)

“…Antagomirs are cholesterol-conjugated single-stranded RNA molecules (21-23 nt) that complementary to the specific miRNA region with either mispairing at the cleavage of Ago2 or some varieties of base modification to inhibit Ago2 cleavages (Krutzfeldt et al, 2005). Some previous studies have revealed that the antagomirs could block the endogenous miRNA expression in cell lines, zebrafish, and tilapia (Morton et al, 2008;Selvamani et al, 2012;Qiang et al, 2017). Therefore, we also conducted this method to verify whether it would impede endogenous miR-206 expression and effect on the target Mc1r gene.…”

miR-192-5p regulates lipid synthesis in non-alcoholic fatty liver disease through SCD-1

“…In addition to regulation by upstream transcription factors, SCD-1 may be repressed through a microRNA-mediated mechanism. Recent studies have demonstrated the roles of miR-125b and miR-29a in the regulation of SCD-1[ 41 , 42 ]. In our study, we found that a region of the SCD 3’ UTR completely matched a seed sequence (5’-UGACCUA-3’) at the binding site of miR-192-5p, demonstrating a direct interaction between miR-192-5p and SCD-1.…”

High Fat Diet-Induced miR-122 Regulates Lipid Metabolism and Fat Deposition in Genetically Improved Farmed Tilapia (GIFT, Oreochromis niloticus) Liver

“…Specific primers for miR-122 are shown in Table 1 . Extraction of miRNAs, synthesis of first-strand cDNA, and qRT-PCR analyses were conducted using the procedures described by Qiang et al (2017b) . We amplified U6 as the reference gene, using the U6 primer supplied in the miRNA SYBR Green qRT-PCR kit (Takara, Dalian, China).…”

“…In Chinese mitten crabs ( Eriocheir sinensis ) fed on fish oil, soybean oil, or a 1:1 fish oil: soybean mixture, the SCD transcript levels were 3.5-, 2-, and 1.3-times higher, respectively, than that in the control group (fed a diet containing 3% base fat) ( Guo et al, 2013 ). The addition of coconut oil (with a high proportion of SFA and a lower proportion of PUFA) to the diet significantly increased SCD transcript levels and increased lipid accumulation in hybrid tilapia ( O. aureus ♂ × O. niloticus ♀) ( Hsieh et al, 2007 ) and GIFT ( Qiang et al, 2017b ). Together, these results suggested that SCD also plays an important role in the regulation of fat metabolism in aquatic animals.…”