Rewiring of embryonic glucose metabolism via suppression of PFK-1 and aldolase during mouse chorioallantoic branching

Abstract

Adapting the energy metabolism state to changing bioenergetic demands is essential for mammalian development accompanying massive cell proliferation and cell differentiation. However, it remains unclear how developing embryos meet the changing bioenergetic demands during the chorioallantoic branching (CB) stage, when the maternal-fetal exchange of gases and nutrients is promoted. In this study, using metabolome analysis with mass-labeled glucose, we found that developing embryos redirected glucose carbon flow into the pentose phosphate pathway via suppression of the key glycolytic enzymes PFK-1 and aldolase during CB. Concomitantly, embryos exhibited an increase in lactate pool size and in the fractional contribution of glycolysis to lactate biosynthesis. Imaging mass spectrometry visualized lactate-rich tissues, such as the dorsal or posterior neural tube, somites and head mesenchyme. Furthermore, we found that the heterochronic gene Lin28a could act as a regulator of the metabolic changes observed during CB. Perturbation of glucose metabolism rewiring by suppressing Lin28a downregulation resulted in perinatal lethality. Thus, our work demonstrates that developing embryos rewire glucose metabolism following CB for normal development.

Temporal regulation of Lin28a during mammalian neurulation contributes to neonatal body size control

“…While iLin28a Tg mice are reported to show leaky Lin28a expression in adult tissues in the absence of Dox treatment, we did not observe such leaky expression in iLin28a Tg embryos at the mid‐gestation stage (Figure B). When exogenous Lin28a expression was induced throughout the embryo by Dox administration at E8.5 and E9.5 to extend the period of Lin28a expression, all Lin28a ‐induced neonates (Dox(+)‐ iLin28a:rtTA Tg) showed perinatal lethality (Figure C), as reported previously . Intriguingly, whereas they did not show any obvious morphological defects, Lin28a ‐induced neonates showed a significant increase in body weight compared to control neonates (Dox(−)‐ iLin28a:rtTA Tg or Dox(+)‐ rtTA Tg neonates) (Figure D).…”

“…ss, somite stage When exogenous Lin28a expression was induced throughout the embryo by Dox administration at E8.5 and E9.5 to extend the period of Lin28a expression, all Lin28a-induced neonates (Dox(+)-iLin28a:rtTA Tg) showed perinatal lethality ( Figure 2C), as reported previously. 11 Intriguingly, whereas they did not show any obvious morphological defects, Lin28a-induced neonates showed a significant increase in body weight compared to control neonates (Dox (−)-iLin28a:rtTA Tg or Dox(+)-rtTA Tg neonates) ( Figure 2D). Particularly, Dox(+)-iLin28a:rtTA Tg exhibited about a 30% increase in body weight compared to that by Dox(+)-rtTA Tg at postnatal day (P) 0.…”

“…Embryos were dissected in cold phosphate buffered saline and fixed with 4% paraformaldehyde overnight at 4 C. The fixed embryos were processed for whole mount in situ hybridization according to standard protocols. 11,24,25 The coding sequence of Lin28a was cloned into the pTA2 vector, and the plasmid was used for RNA probe synthesis. The stained embryos were…”

“…Considering the dynamic expression patterns of Lin28a during mammalian development, we reasoned that it is important to manipulate the level of Lin28a temporally to understand its role during embryogenesis. We have previously shown that glucose metabolism rewiring at the neurulation stage is perturbed by sustained Lin28a expression beyond E8.5 . In this study, to further investigate the significance of temporally regulated Lin28a expression during mammalian development, we perturbed the dynamics of Lin28a expression by transiently inducing exogenous Lin28a at different times during development using the Tet‐ON system and examined its effects on mouse development.…”

Mammalian embryos show metabolic plasticity toward the surrounding environment during neural tube closure

“…Central carbon metabolism affects various biological processes, such as cell proliferation and cell differentiation, while exerting housekeeping functions for cellular homeostasis (Pavlova & Thompson, 2016;Vander Heiden, Cantley, & Thompson, 2009). Coordinating metabolic rewiring with development in a spatiotemporal manner is essential for normal development (Agathocleous et al, 2012;Bulusu et al, 2017;Homem et al, 2014;Miyazawa et al, 2017;Nagaraj et al, 2017;Oginuma et al, 2017;Tennessen, Baker, Lam, Evans, & Thummel, 2011), in which developmental events are precisely coordinated in time and space. However, it remains to be shown how developing embryos couple energy metabolism with developmental progression.…”