Regulation of hepatic pyruvate dehydrogenase phosphorylation in offspring glucose intolerance induced by intrauterine hyperglycemia

High glucose exposure of preimplantation embryos causes glucose intolerance and insulin resistance in F1 and F2 male offspring

BACKGROUND

Although studies suggest that maternal high glucose (HG) increases offspring susceptibility to type 2 diabetes mellitus (T2DM), the underlying mechanisms are largely unclear. We studied whether glucose levels in oviducts are elevated when pregestational diabetic females get pregnant and whether the oviductal HG (OVHG) would act directly on embryos to increase offspring's T2DM susceptibility.

METHODS

We established an in vivo model of OVHG by injecting female mice with streptozotocin (STZ) during the preimplantation period and an in vitro model of embryo culture with HG (ECHG) by culturing preimplantation embryos with HG, before examining glucose tolerance and insulin resistance (IR) in F1 and F2 offspring.

FINDINGS

Injection of female mice with STZ induced a lasting significant glucose elevation in blood and oviduct fluid during the preimplantation period. The glucose tolerance test showed that both the STZ-induced OVHG and the ECHG caused glucose intolerance in F1 male and F1-sired F2 male offspring but had no effect on female offspring. Insulin tolerance test and the analysis for IR-related gene expression and glycogen contents in liver and muscle revealed significant IR in these male offspring.

INTERPRETATION

This study provided evidence that HG can act directly on preimplantation embryos to increase offspring's T2DM susceptibility suggesting that the preimplantation period is a critical stage for transmission of mother's diabetes to offspring. FUND: This study was supported by grants from the China National Natural Science Foundation (Nos. 31772599, 32072738, 31702114, and 31902160), and the Natural Science Foundation of Shandong Province (Nos. ZR2022MC036, ZR2017BC025 and ZR2020QC102).

Regulation of malonyl-CoA-acyl carrier protein transacylase network in umbilical cord blood affected by intrauterine hyperglycemia

Background

Gestational diabetes mellitus (GDM) has been shown to be associated with high risk of diabetes in offspring. However, the mechanisms involved in the insulin resistance in offspring are still unclear. Mitochondrial dysfunction is related with insulin resistance. In mitochondria, malonyl-CoA-acyl carrier protein transacylase (MCAT) is the key enzyme of mitochondrial fatty acid synthesis and is estimated to contribute to insulin resistance. In this study, we aimed to examine the role of MCAT and its network in the umbilical cord blood in GDM-induced offspring insulin resistance.

Methods

We isolated lymphocytes from umbilical cord vein blood in 6 GDM patients and 6 controls and examined the differences of RNA by RNA sequencing. qRT-PCR and western blot were used to measure mRNA and protein changes. Bisulfite genomic sequencing PCR was applied to detect DNA methylation.

Results

We found more than 400 genes were differentially regulated in the lymphocytes of umbilical cord blood from GDM patients and these genes were mainly enriched in immune system and endocrine system, which relate to mitochondrial dysfunction and insulin resistance. MCAT closely related with PTPN1 (Protein Tyrosine Phosphatase, Non-Receptor Type1) and STAT5A (Signal Transducer And Activator of Transcription 5A), which were all increased in umbilical cord blood from GDM patients. Increase in MCAT may be due to decreased MCAT DNA methylation.

Conclusion

MCAT and its network with PTPN1, STAT5A are regulated in umbilical cord blood affected by maternal intrauterine hyperglycemia.