Li Xin, Zhang Hao, Wang Yong, Li Yanyan, Wang Youli, Xiong Yan, Liu Wei, Lin Yaqiu
Key Laboratory of Qinghai-Tibetan Plateau Animal Genetic Resource Reservation and Utilization, Ministry of Education, Southwest Minzu University, Chengdu 610041 , China.
Key Laboratory of Qinghai-Tibetan Plateau Animal Genetic Resource Reservation and Exploitation of Sichuan Province, Southwest Minzu University, Chengdu 610041, China.
Anim Biosci. 2025 Apr;38(4):577-587. doi: 10.5713/ab.24.0322. Epub 2024 Oct 25.
Circular RNAs (circRNAs) are widely involved in the regulation of lipid deposition in animals, but there are few reports on key circRNAs regulating intramuscular adipocyte differentiation in goats. Therefore, this study took an abundantly expressed in goat adipocytes chi-circ_0009659 as the object.
Based on the identification of back splicing site in chi-circ_0009659, its expression level during the goat intramuscular preadipocyte differentiation was detected by quantitative polymerase chain reaction (qPCR) . The chi-circ_0009659 loss-of-function and gain-of-function cell models were obtained by adenovirus and smarter silencer, respectively. and the adipocyte differentiation were explored by Oil Red O staining, Bodipy staining and qPCR. Its major cytoplasmic localization was determined by fluorescence in situ hybridization (FISH), nucleocytoplasmic separation and qPCR. The interaction between chi-circ_0009659, miR-3431-5p, and STEAP family member 4 (STEAP4) was verified by bioinformatics, RNA pull down and dual luciferase reporter assay.
Silencing chi-circ_0009659 inhibited lipid droplet accumulation and the expression of differentiation-determining genes in goat intramuscular adipocytes, while overexpression of chi-circ_0009659 reversed these results. chi-circ_0009659 was predominantly localized to the cytoplasm and could regulate miR-3431 expression which in turn affects STEAP4. Consistent with expectations, miR-3431-5p acted as a negative regulator of GIMPA differentiation, while STEAP4 promoted differentiation.
We demonstrated chi-circ_0009659 positively regulates goat intramuscular preadipocyte differentiation by sponging miR-3431-5p to further regulate the expression of STEAP4. This research provides a new reference for in-depth understanding of the effects of circRNA on adipocyte differentiation.
环状RNA（circRNAs）广泛参与动物脂质沉积的调控，但关于调控山羊肌内脂肪细胞分化的关键circRNAs的报道较少。因此，本研究以在山羊脂肪细胞中高表达的chi-circ_0009659为研究对象。
基于对chi-circ_0009659反向剪接位点的鉴定，通过定量聚合酶链反应（qPCR）检测其在山羊肌内前体脂肪细胞分化过程中的表达水平。分别通过腺病毒和更智能的沉默剂构建chi-circ_0009659功能缺失和功能获得细胞模型，并通过油红O染色、Bodipy染色和qPCR探究脂肪细胞分化情况。通过荧光原位杂交（FISH）、核质分离和qPCR确定其主要的细胞质定位。通过生物信息学、RNA下拉和双荧光素酶报告基因检测验证chi-circ_0009659、miR-3431-5p和STEAP家族成员4（STEAP4）之间的相互作用。
沉默chi-circ_0009659可抑制山羊肌内脂肪细胞中脂滴积累和分化决定基因的表达，而chi-circ_0009659的过表达则逆转了这些结果。chi-circ_0009659主要定位于细胞质，可调节miR-3431的表达，进而影响STEAP4。与预期一致，miR-3431-5p作为山羊肌内前体脂肪细胞（GIMPA）分化的负调节因子，而STEAP4促进分化。
我们证明chi-circ_0009659通过海绵吸附miR-3431-5p来进一步调节STEAP4的表达，从而正向调节山羊肌内前体脂肪细胞的分化。本研究为深入了解circRNA对脂肪细胞分化的影响提供了新的参考。
