Melatonin improves the vitrification of sheep morulae by modulating transcriptome

Pengyun Ji; Yunjie Liu; Laiqing Yan; Yanquan Jia; Mengmeng Zhao; Dongying Lv; Yujun Yao; Wenkui Ma; Depeng Yin; Fenze Liu; Shuai Gao; Abulizi Wusiman; Kailun Yang; Lu Zhang; Guoshi Liu

doi:10.3389/fvets.2023.1212047

Melatonin improves the vitrification of sheep morulae by modulating transcriptome

Front Vet Sci. 2023 Oct 18:10:1212047. doi: 10.3389/fvets.2023.1212047. eCollection 2023.

Authors

Pengyun Ji^{1

2}, Yunjie Liu², Laiqing Yan², Yanquan Jia³, Mengmeng Zhao², Dongying Lv², Yujun Yao², Wenkui Ma^{1

2}, Depeng Yin², Fenze Liu⁴, Shuai Gao², Abulizi Wusiman¹, Kailun Yang¹, Lu Zhang², Guoshi Liu²

Affiliations

¹ College of Animal Science, Xinjiang Agricultural University, Urumqi, China.
² National Engineering Laboratory for Animal Breeding, College of Animal Science and Technology, China Agricultural University, Beijing, China.
³ Beijing Jiaen Hospital, Beijing, China.
⁴ Inner Mongolia Golden Grassland Ecological Technology Group Co., Ltd., Inner Mongolia, China.

Abstract

Embryo vitrification technology is widely used in livestock production, but freezing injury has been a key factor hindering the efficiency of embryo production. There is an urgent need to further analyze the molecular mechanism of embryo damage by the vitrification process. In the study, morulae were collected from Hu sheep uterine horns after superovulation and sperm transfusion. Morulae were Cryotop vitrified and warmed. Nine morulae were in the vitrified control group (frozen), and seven morulae were vitrified and warmed with 10^-5 M melatonin (melatonin). Eleven non-frozen morulae were used as controls (fresh). After warming, each embryo was sequenced separately for library construction and gene expression analysis. p < 0.05 was used to differentiate differentially expressed genes (DEG). The results showed that differentiated differentially expressed genes (DEG) in vitrified morulae were mainly enriched in protein kinase activity, adhesion processes, calcium signaling pathways and Wnt, PI3K/AKT, Ras, ErbB, and MAPK signaling pathways compared to controls. Importantly, melatonin treatment upregulated the expression of key pathways that increase the resistance of morulae against vitrification induced damage. These pathways include kinase activity pathway, ErbB, and PI3K/Akt signaling pathway. It is worth mentioning that melatonin upregulates the expression of XPA, which is a key transcription factor for DNA repair. In conclusion, vitrification affected the transcriptome of in vivo-derived Hu sheep morulae, and melatonin had a protective effect on the vitrification process. For the first time, the transcriptome profiles caused by vitrification and melatonin in sheep morulae were analyzed in single embryo level. These data obtained from the single embryo level provide an important molecular mechanism for further optimizing the cryopreservation of embryos or other cells.

Keywords: DNA repair; RNA-seq; antioxidant; cryoprotectant; embryo freezing.