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The circadian rhythm of melatonin secretion in the pineal gland is highly conserved in vertebrates. Melatonin levels are always elevated at night. Acetylserotonin O-methyltransferase (ASMT) is the last enzyme in the regulation of melatonin biosynthesis (N-acetyl-5-hydroxytryptamine-melatonin). S-adenosylmethionine (SAM) is an important methyl donor in mammals and can be used as a substrate for the synthesis of melatonin. Methionine adenosyltransferase (MAT) catalyzes the synthesis of SAM from methionine and ATP and has a circadian rhythm. CircRNA is an emerging type of endogenous noncoding RNA with a closed loop. Whether circRNAs in the pineal gland can participate in the regulation of melatonin synthesis by binding miRNAs to target mat2a as part of the circadian rhythm is still unclear. In this study, we predicted the targeting relationship of differentially expressed circRNAs, miRNAs and mRNAs based on the results of rat pineal RNA sequencing. Mat2a siRNA transfection confirmed that mat2a is involved in the synthesis of melatonin. Circ-ERC2 and miR-125a-5p were screened out by software prediction, dual-luciferase reporter experiments, cell transfection, etc. Finally, we constructed a rat superior cervical ganglionectomy model (SCGx), and the results showed that circ-ERC2 could participate in the synthesis of melatonin through the miR-125a-5p/MAT2A axis. The results of the study revealed that circ-ERC2 can act as a molecular sponge of miR-125a-5p to regulate the synthesis of melatonin in the pineal gland by targeting mat2a. This experiment provides a basis for research on the circadian rhythm of noncoding RNA on pineal melatonin secretion. [ABSTRACT FROM AUTHOR]

Simple Summary: GnRH and FSH play an important regulatory role in the reproductive activities of mammals. At present, many artificially synthesized GnRH analogues have been used in the regulation of cattle reproduction and the clinical treatment of various reproductive diseases. This study explored the potential mechanism of miR-488 in GnRH regulation of FSH synthesis and secretion and provides a theoretical basis for the application of GnRH analogue in cattle artificial breeding. We hope to provide a research foundation for improving the processing procedures of cattle estrus control and the domestic application of hormone products. Gonadotropin-releasing hormone (GnRH), which is synthesized and released by the hypothalamus, promotes the synthesis and secretion of follicle-stimulating hormone (FSH), thereby regulating the growth and reproduction of animals. GnRH analogues have been widely used in livestock production. MiRNAs, which are endogenous non-coding RNAs, have been found to play important roles in hormone regulation and other physiological processes in recent years. However, the roles of miRNAs in GnRH-mediated regulation of FSH secretion have rarely been studied. Herein, we treated bovine anterior adenohypophyseal cells with an exogenous GnRH analogue and found that miR-488 was differentially expressed. Through a combination of TargetScan prediction and dual luciferase reporter analysis, miR-488 was confirmed to be able to target the FSHB gene. Based on this finding, we verified the expression of Fshβ and Lhβ mRNA in the rat adenohypophysis before and after exogenous GnRH treatment in vivo and in vitro. Experiments on rat anterior adenohypophyseal cells showed that overexpression of miR-488 significantly inhibited Fshβ expression and FSH synthesis, while knockdown of miR-488 had the opposite effects. Our results demonstrate that GnRH relies on miR-488 to regulate FSH synthesis, providing additional useful evidence for the significance of miRNAs in the regulation of animal reproduction. [ABSTRACT FROM AUTHOR]

Simple Summary: Fat differentiation affects lipid deposition and is a complex metabolic process. It has been previously reported that multiple transcription factors regulate adipocyte formation. With the in-depth study of epigenetics, in recent years it has been reported that long noncoding RNA (lncRNA) can effectively affect the formation of lipid droplets and thus regulate fat deposition. lncRNA can regulate cell function through a variety of mechanisms, the most studied is the mechanism of action of lncRNA as a miRNA molecular sponge. The purpose of this article is to explore the role of transforming growth factor-beta (TGF-β1) mediated lncRNA in the formation of porcine adipocytes, from the perspective of lncRNA to reveal the effect of TGF-β1 on the differentiation of porcine adipocytes, and provide a new way to improve the quality of pork. Adipocyte differentiation and lipid metabolism have important regulatory effects on the quality of meat from livestock. A variety of transcription factors regulate preadipocyte differentiation. Several studies have revealed that transforming growth factor-beta (TGF-β1) may play a key role in epithelial–mesenchymal transition (EMT); however, little is known about the effects of TGF-β1 treatment on porcine preadipocytes. To explore the role of TGF-β1 in porcine adipocyte differentiation, porcine preadipocytes were treated with 10 ng/mL TGF-β1, and two libraries were constructed for RNA-seq. We chose an abundant and differentially expressed long noncoding RNA (lncRNA), which we named fat deposition-associated long noncoding RNA1 (FDNCR1), for further study. RT-qPCR was used to detect mRNA levels of genes related to adipocyte differentiation. Triglyceride assay kits were used to detect lipid droplet deposition. TGF-β1 significantly suppressed porcine preadipocyte differentiation. We identified 8158 lncRNAs in total and 39 differentially expressed lncRNAs. After transfection with FDNCR1 siRNA, the mRNA expression of aP2, C/EBPα, and PPARγ and triglyceride levels significantly increased. Transfection with FDNCR1 siRNA significantly decreased protein levels of p-Smad2/Smad2 and p-Smad3/Smad3. These results demonstrate that FDNCR1 suppresses porcine preadipocyte differentiation via the TGF-β signaling pathway. [ABSTRACT FROM AUTHOR]