Tingting Jiang

Background: Brown adipose tissue (BAT) is indispensable for producing heat and contributes critically to the survival of neonatal mammals. MicroRNAs (miRNAs) are small noncoding RNAs that serve as key post-transcriptional regulators, playing a crucial role in regulating BAT development and thermogenesis. However, the role of miR-326-3p in goat brown adipocytes remains largely unclear. Methods: Primary brown adipocytes were isolated from goat perirenal adipose tissue and subjected to gain and loss-of-function assays using miR-326-3p mimics and inhibitors. Lipid accumulation, thermogenic-related genes, and mitochondrial gene expression were quantified by Oil Red O staining and qRT-PCR. Target prediction and dual-luciferase reporter assays were performed to validate direct interaction between miR-326-3p and FGF11. Results: Expression profiling demonstrated that miR-326-3p is more enriched in brown adipose tissue (BAT) than in white adipose tissue (WAT), and the expression level gradually decreases with adipocyte differentiation. miR-326-3p overexpression significantly inhibited lipid droplet accumulation and the expression of genes associated with differentiation, thermogenesis, and mitochondria, including PPARγ, FABP4, UCP1, and PGC1α, whereas inhibition produced the opposite effect. Bioinformatic prediction and dual-luciferase reporter assays further identified fibroblast growth factor 11 (FGF11) as a direct target of miR-326-3p. Conclusions: These findings reveal that miR-326-3p negatively regulates the differentiation and expression of thermogenic-related genes of goat brown adipocytes, uncovering a novel miR-326-3p-FGF11 regulatory axis.

Brown adipose tissue (BAT) is the main site of adaptive thermogenesis, generates heat to maintain body temperature upon cold exposure, and protects against obesity by promoting energy expenditure. RNA-seq analysis revealed that FGF11 is enriched in BAT. However, the functions and regulatory mechanisms of FGF11 in BAT thermogenesis are still limited. In this study, we found that FGF11 was significantly enriched in goat BAT compared with white adipose tissue (WAT). Gain- and loss-of-function experiments revealed that FGF11 promoted differentiation and thermogenesis in brown adipocytes. However, FGF11 had no effect on white adipocyte differentiation. Furthermore, FGF11 promoted the expression of the UCP1 protein and an EBF2 element was responsible for UCP1 promoter activity. Additionally, FGF11 induced UCP1 gene expression through promoting EBF2 binding to the UCP1 promoter. These results revealed that FGF11 promotes differentiation and thermogenesis in brown adipocytes but not in white adipocytes of goats. These findings provide evidence for FGF11 and transcription factor regulatory functions in controlling brown adipose thermogenesis of goats.

Brown adipose tissue (BAT) plays a critical role in maintaining the body temperature in newborn lamb due to its unique non-shivering thermogenesis. Previous studies have found that BAT thermogenesis is regulated by several long non-coding RNAs (lncRNAs). Here, we identified a novel lncRNA, MSTRG.310246.1, which was enriched in BAT. MSTRG.310246.1 was localized in both the nuclear and cytoplasmic compartments. In addition, MSTRG.310246.1 expression was upregulated during brown adipocyte differentiation. Overexpression of MSTRG.310246.1 increased the differentiation and thermogenesis of goat brown adipocytes. On the contrary, the knockdown of MSTRG.310246.1 inhibited the differentiation and thermogenesis of goat brown adipocytes. However, MSTRG.310246.1 had no effect on goat white adipocyte differentiation and thermogenesis. Our results show that MSTRG.310246.1 is a BAT-enriched LncRNA that improves the differentiation and thermogenesis of goat brown adipocytes.