Role of Wnt Signaling During In-Vitro Bovine Blastocyst Development and Maturation in Synergism with PPARδ Signaling.

Tabinda Sidrat,Il-Keun Kong,Kyeong-Lim Lee,Lianguang Xu,Muhammad Idrees,Myeong-Don Joo,Abdul Aziz Khan

doi:10.3390/cells9040923

Abstract

Wnt/β-catenin signaling plays vital role in the regulation of cellular proliferation, migration, stem cells cell renewal and genetic stability. This pathway is crucial during the early developmental process; however, the distinct role of Wnt/β-catenin signaling during pre-implantation period of bovine embryonic development is obscure. Here, we evaluated the critical role of Wnt/β-catenin pathway in the regulation of bovine blastocyst (BL) development and hatching. 6 bromoindurbin-3’oxime (6-Bio) was used to stimulate the Wnt signaling. Treatment with 6-Bio induced the expression of peroxisome proliferator-activated receptor-delta (PPARδ). Interestingly, the PPARδ co-localized with β-catenin and form a complex with TCF/LEF transcription factor. This complex potentiated the expression of several Wnt directed genes, which regulate early embryonic development. Inhibition of PPARδ with selective inhibitor 4-chloro-N-(2-{[5-trifluoromethyl]-2-pyridyl]sulfonyl}ethyl)benzamide (Gsk3787) severely perturbed the BL formation and hatching. The addition of Wnt agonist successfully rescued the BL formation and hatching ability. Importantly, the activation of PPARδ expression by Wnt stimulation enhanced cell proliferation and fatty acid oxidation (FAO) metabolism to improve BL development and hatching. In conclusion, our study provides the evidence that Wnt induced PPARδ expression co-localizes with β-catenin and is a likely candidate of canonical Wnt pathway for the regulation of bovine embryonic development.

Highlights

The development of oocyte into an implantation competent blastocyst (BL) undergoes a series of progressive developmental events
Cumulus Oocyte Complexes (COCs) were randomly placed in six groups (50-55 COCs per group). 6 bromoindurbin-3’oxime (6-Bio) was added in each group in 700 μL-volume of culture medium to achieve the final concentration of 0 nM, 200 nM, 300 nM, 400 nM and 500 nM
We determined during in-vitro maturation and culturing of bovine embryonic development

Summary

Introduction

The development of oocyte into an implantation competent blastocyst (BL) undergoes a series of progressive developmental events. During this process the classical developmental signaling cascades participate to ensure the successful implantation and subsequently improve the pregnancy outcomes [1]. A huge body of evidences has accumulated during the past years that has underlined the importance of Wnt signaling during the pre-implantation period of vertebrate embryonic development [2]. Wnt are a secreted glycoprotein that regulates a plethora of biological functions, including cell proliferation, cell polarity and cell fate determination during embryonic development and tissue homeostasis [3]. The Wnt ligands can activate three distinct intracellular signaling cascades which initiate different biological responses.

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