Inhibition of apical domain formation does not block blastocyst development in bovine embryos

Author(s)

dos Anjos, S. A. A. ^{[1, 2]} ; da Costa, C. P. ^[1] ; Assumpcao, M. E. O. A. ^[1] ; Visintin, J. A. ^[1] ; Goissis, M. D. ^[1]

Affiliation

^[1] Univ Sao Paulo, Dept Anim Reprod, Coll Vet Med & Anim Sci, Av Orlando Marques de Paiva 87, BR-05508270 Sao Paulo, SP - Brazil

^[2] Univ Sao Paulo, Inst Biosci, Av Orlando Marques de Paiva 87, BR-05508270 Sao Paulo, SP - Brazil

• Document type: Journal article
• Source: REPRODUCTION FERTILITY AND DEVELOPMENT; v. 33, n. 10, p. 665-673, AUG 11 2021.
• Web of Science Citations: 0

Abstract

The first event of cellular differentiation consists of the segregation of the trophectoderm and the inner cell mass. Studies in mice suggest that cell contractility and the formation of an apical domain play important roles in this event; however, this remains unknown in the bovine. We tested the hypothesis that blocking apical domain formation would halt subsequent trophectoderm differentiation in bovine embryos. We first assessed the formation of an apical domain by the presence of Par-6 Family Cell Polarity Regulator Beta (PARD6B) and Ezrin (EZR), which appeared after the 8-cell stage. We inhibited apical domain formation by blocking cell contractility with 25 mu M (-)-blebbistatin. Treatment from 90 to 186 h after insemination did not reduce blastocyst development compared with the untreated control group or the group treated with inactive (-)-blebbistatin. Immunofluorescence staining after blebbistatin treatment revealed the absence of EZR and the trophectoderm marker Caudal Type Homeobox 2 (CDX2). Following blebbistatin treatment, Yes1 Associated Transcriptional Regulator (YAP), which is involved in the Hippo signalling pathway, exhibited cytoplasmic staining instead of nuclear localisation. Despite changes in protein expression and localisation, no difference in trophectoderm or total cell numbers was observed. In conclusion, inhibition of cell contractility inhibited apical domain formation without impairing blastocyst formation, suggesting that a different biological mechanism is involved in trophectoderm and inner cell mass differentiation in bovine embryos. (AU)

• FAPESP's process: 17/09576-3 - Studies on cell differentiation mechanisms during early bovine embryo development
• Grantee: Marcelo Demarchi Goissis
• Support Opportunities: Research Grants - Young Investigators Grants
• FAPESP's process: 18/08285-8 - Influence of cell contractility on the formation of apical domains and lineage segregation in the bovine embryo
• Grantee: Samuel Augusto Aguiar dos Anjos
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• FAPESP's process: 18/18924-8 - Influence of the HIPPO signaling pathway on the segregation between the inner cell mass and the trophectoderm in bovine embryos
• Grantee: Caroline Pereira da Costa
• Support Opportunities: Scholarships in Brazil - Master
• FAPESP's process: 17/25574-0 - Studies on cell differentiation mechanisms during early bovine embryo development
• Grantee: Marcelo Demarchi Goissis
• Support Opportunities: Scholarships in Brazil - Young Researchers