CircRNA Expression Profile during Yak Adipocyte Differentiation and Screen Potential circRNAs for Adipocyte Differentiation.

Yongfeng Zhang,Chunnina Liang,Xuezhi Ding,Ping Yan,Xiaoyun Wu,Jie Pei,Min Chu,Xian Guo

doi:10.3390/genes11040414

Abstract

The yak (Bos grunniens) is subjected to nutritional deficiency during the whole winter grazing season; deciphering the adipose metabolism and energy homeostasis under cold and nutrients stress conditions could be a novel way to understand the specific mechanism of energy metabolism. Circular RNAs (circRNAs) have elucidated that they play a key role in many biological events, but the regulatory function of adipose development remains mostly unknown. Therefore, the expression pattern of circRNAs were identified for the first time during yak adipocyte differentiation to gain insight into their potential functional involvement in bovine adipogenesis. We detected 7203 circRNA candidates, most of them contained at least two exons, and multiple circRNA isoforms could be generated from one parental gene. Analysis of differential expression circRNAs displayed that 136 circRNAs were differentially expressed at day 12 (Ad) after adipocyte differentiation, compared with the control at day 0 (Pread 0), while 7 circRNAs were detected on day 2. Sanger sequencing validated that six circRNAs had head-to-tail junction, and quantitative real-time PCR (qPCR) results revealed that the expression patterns of ten circRNAs were consistent with their expression levels from RNA-sequencing (RNA-seq) data. We further predicted the networks of circRNA-miRNA-gene based on miRNAs sponging by circRNAs, in which genes were participated in the adipocyte differentiation-related signaling pathways. After that, we constructed several adipocyte differentiation-related ceRNAs and revealed six circRNAs (novel_circ_0009127, novel_circ_0000628, novel_circ_0011513, novel_circ_0010775, novel_circ_0006981 and novel_circ_0001494) were related to adipogenesis. Furthermore, we analyzed the homology among yak, human and mouse circRNAs and found that 3536 yak circRNAs were homologous to human and mouse circRNAs. In conclusion, these findings provide a solid basis for the investigation of yak adipocyte differentiation-related circRNAs and serve as a great reference to study the energy metabolism of high-altitude animals.

Highlights

IntroductionThere are more than 15 million yaks living on the Qinghai Tibetan Plateau, which represents about 90 percent of the world’s yak population
Yak is an iconic symbol of the Qinghai Tibetan Plateau [1]
7203 circRNAs were identified during yak adipocyte differentiation at days 0, 2, and 12, of which 4139 circRNAs were detected at day 0, 4755 at day 2, 5505 at day 12, and 2737 at all three-time points (Figure 2A)

Summary

Introduction

There are more than 15 million yaks living on the Qinghai Tibetan Plateau, which represents about 90 percent of the world’s yak population. Yaks are essential for Tibetans and other nomadic pastoralists living in high-altitude surroundings and furnish the primary resources such as meat, milk, transportation, dung. Yak store maximum energy in the adipose tissues during the summer season (June to September) when raised on lush pastures, this stored energy is utilized by yak to survive during the long cold season (October to May) [2]. Over the past several decades, abundant research has explored the molecular mechanisms of adipose tissue development and adipocyte differentiation. Exploration of the molecular mechanisms that modulate proliferation, differentiation, and metabolism of yak adipocytes may reveal a new clue to elucidate the development of adipose tissues in plateau animals

Objectives

Methods

Results

Discussion

Conclusion