Maternal Diabetes In Vivo and High Glucose In Vitro Diminish GAPDH Activity in Rat Embryos

Abstract

The aim of the present study was to investigate whether diabetic embryopathy may be associated with the inhibition of glyceraldehyde-3-phosphate dehydrogenase (GAPDH) resulting from an excess of reactive oxygen species (ROS) in the embryo. Recent demonstrations of enhanced ROS production in mitochondria of bovine aortic endothelial cells exposed to high glucose have supported the idea that the pathogenesis of diabetic complications may involve ROS-induced GAPDH inhibition. We investigated whether a teratogenic diabetic environment also inhibits embryonic GAPDH activity and alters GAPDH gene expression and whether antioxidants diminish such GAPDH inhibition. In addition, we determined whether the inhibition of GAPDH with iodoacetate induces dysmorphogenesis, analogous to that caused by high glucose concentration, and whether antioxidants modulated the putative teratogenic effect of such direct GAPDH inhibition. We found that embryos from diabetic rats and embryos cultured in high glucose concentrations showed decreased activity of GAPDH (by 40 -60%) and severe dysmorphogenesis on gestational days 10.5 and 11.5. GAPDH mRNA was decreased in embryos of diabetic rats compared to control embryos. Supplementing the high-glucose culture with the antioxidant N-acetylcysteine (NAC) increased GAPDH activity and diminished embryonic dysmorphogenesis. Embryos cultured with iodoacetate showed both decreased GAPDH activity and dysmorphogenesis; supplementing the culture with NAC increased both parameters toward normal values. In conclusion, dysmorphogenesis caused by maternal diabetes is correlated with ROS-induced inhibition of GAPDH in embryos, which could indicate that inhibition of GAPDH plays a causal role in diabetic embryopathy. Diabetes

The embryonic stress response to in vitro culture: insight from genomic analysis

“…According to the long-standing consensus, the polyol, advanced glycation end product, PKC and hexosamine pathways are activated due to increased mitochondrial ROS production, which inhibits GAPDH activity (Nishikawa et al 2000). Such an effect has been observed in embryos from diabetic mothers (Wentzel et al 2001, Wentzel et al 2003 or cultured under stress created by high glucose concentrations (Karja et al 2006), suggesting that energetic stress in pre-implantation embryos is a result of compromised OXPHOS (Moley et al 1996, Chi et al 2002, Mitchell et al 2009). …”

Long-term effect of maternal obesity on pancreatic beta cells of offspring: reduced beta cell adaptation to high glucose and high-fat diet challenges in adult female mouse offspring

“…Absorbance at 340 nm was measured on a Hitachi 2500 spectrophotometer (Technical Lab Services, Toronto, ON, Canada) for 10 min. Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) activity was confirmed by measuring the conversion of NADH to NAD + at 340 nm in the backward reaction starting with glycerate-3-phosphate using glycerate-3-phosphate kinase plus ATP as described previously [20].…”

Glucose utilization and the PI3-K pathway: mechanisms for cell survival in preimplantation embryos

“…This panel shows representative uterine horns derived from mice into which blastocysts cultured in either control media or iodoacetate were transferred. Wentzel et al (2003) demonstrated that the inhibition of GAPDH activity by iodoacetate in gestational day 11 rat embryos, results in increased malformation rates as well as decreased size, somite number, and DNA and protein content. Thus the inhibition of glycolysis has harmful effects on both pre-and post-implantation embryo development.…”