Endocrine Abstracts

Obesity, as a chronic nutritional disorder, is a high-risk factor for type 2 diabetes, fatty liver and other metabolic diseases. Multiple lncRNAs have been confirmed concerning adipocyte differentiation and thus affect obesity, such as ADINR, Paral1, etc. Previously, we identified a lncRNA named ENST0000052114 (abbreviated to lncRNA52114), highly expressed in human mature adipocytes by differential lncRNA expression profile. Here, we explored the role and mechanism of lncRNA52114 in the differentiation of human preadipocytes from visceral adipose (HPA-vis). Overexpressed or silencing lentiviral vector of lncRNA52114 was constructed. After transfection of precursor cells, the infection efficiency of lentivirus was observed by fluorescence microscope and was verified by qPCR. The classical induction protocol (1-methyl-3-isobutylxanthine, dexamethasone, insulin, and rosiglitazone) was used to induce HPA-vis to mature adipocytes. The morphology and lipid droplet size of adipocytes were detected by oil red O staining, and the content of triglyceride was detected by chemiluminescence method. qPCR and Western Blot were used to detect the mRNA and protein expression levels of adipocyte differentiation (PPARγ, C/EBPα, C/EBPβ, FABP4, etc.). Compared with the control groups, there was no significant change in oil red O staining, triglyceride content, differentiation marker genes expression levels in the lncRNA52114 overexpression groups. On the contrary, the silence of lncRNA52114 expression can significantly inhibit the differentiation rate of HPA-vis compared with the control groups, which is manifested by the decrease of the lipid droplets number and triglyceride content in mature adipocytes. The mRNA and protein expression levels of C/EBPα, C/EBPβ and FABP4 were significantly downregulated in silence group. Fluorescence in situ hybridization (FISH) showed that lncRNA52114 was highly expressed in nucleus and also in cytoplasm. RNA transcriptome sequencing found that the differentially expressed genes were mainly concentrated in the thyroid hormone synthesis pathway (TSHR, GPX3, etc.). Among those genes, TSHR was significantly reduced after lncRNA52114 silencing and closely related to adipocyte differentiation. Overexpression of TSHR on the basis of lncRNA52114 silencing can reverse the effect of its silencing on adipocytes differentiation. CUT&TAG and CUT&RUN showed that lncRNA52114 can decrease the enrichment level of H3K4me3 in TSHR promoter region. LncRNA52114 may influence the differentiation of adipocytes by downregulating the TSHR histone modification in the thyroid hormone synthesis signaling pathway. This study will provide a new theoretical basis and experimental evidence for the study of adipocyte differentiation and a potential target for the prevention and treatment of obesity.