Stress signaling in mammalian oocytes and embryos: a basis for intervention and improvement of outcomes

Abstract

Oocytes and early stage embryos are highly sensitive to variation in diverse exogenous factors such as temperature, osmolarity, oxygen, nutrient restriction, pH, shear stress, toxins, amino acid availability, and lipids. It is becoming increasingly apparent that many such factors negatively affect the endoplasmic reticulum, protein synthesis and protein processing, initiating ER stress and unfolded protein responses. As a result, ER stress signaling serves as a common mediator of cellular responses to diverse stressors. In oocytes and embryos, this leads to developmental arrest and epigenetic changes. Recent studies have revealed that preventing ER stress or inhibiting ER stress signaling can preserve or even enhance oocyte and embryo developmental potential. This chapter reviews ER stress signaling, how it arises, how it affects oocytes and embryos, and how its occurrence can be managed or prevented.

Correlation between Sestrin-2 and PERK Signaling in Matured Porcine Oocytes according to ER-stress during In Vitro Maturation

“…PERK signal activation plays important role in oocyte maturation, in vitro fertilization (IVF) process, and blastocyst development (Latham KE., 2016). The expressions of PERK-related proteins were increased during IVM progression in CCs and COCs (data not shown).…”

Policy of IVF centres towards oocytes affected by Smooth Endoplasmic Reticulum aggregates: a multicentre survey study

“…However, they have also been observed in unfertilized oocytes, aging oocytes and embryos [3,11,18]. New evidence demonstrates that the Endoplasmic Reticulum (smooth or rough) plays additional crucial roles in stress responses in the oocyte or embryo [19] as well as in the regulation of the meiotic spindle [20]. Different malformations and pathologies have been described after transfer of an embryo originating from a SERa+ oocyte [21,22] but equally when a non affected embryo from the same oocyte cohort is transferred [9,12].…”

Competência oocitária: importância e fatores determinantes in vivo e in vitro

“…O estresse consiste em outro importante fator que interfere negativamente na qualidade do oócito e fertilidade de diversas espécies animais inclusive no ser humano. Diversas situações podem representar estresse incluindo desde aspectos climáticos, nutricionais e de manejo aos quais as fêmeas são submetidas até variações locais do cultivo oocitário in vitro (Latham, 2016). Segundo Prasad et al (2016), o aumento do nível circulante de cortisol é acompanhado por redução da concentração sérica de estradiol muito possivelmente devido a indução de estresse oxidativo nas células da granulosa que compõe o folículo e sustentam o desenvolvimento oocitário.…”