Intrauterine hyperglycemia exposure per se altered metabolic functions in F2 offspring via reprogramming F1 PGCs

Intrauterine hyperglycemia has been linked to an elevated risk of diabetes in next and further generations. Existing reports about transmission effects of intrauterine hyperglycemia have included both intrauterine and postnatal metabolic exposure factors, the impact of intrauterine hyperglycemia per se has not been separately assessed. To investigate effect of intrauterine hyperglycemia exposure per se on further generations, we selected non-phenotypic F1-GDM and F2-GDM male mice to examin metabolic changes in next generation and performed a methylome on day 13.5 primordial germ cells (PGCs) of F1-GDM male fetus to explore its underlying mechanism. We found that intrauterine hyperglycemia exposure per se resulted in obesity, insulin resistance and/or glucose intolerance in F2 male mice, and no changes in F3 male mice. Methylome of day 13.5 PGCs of F1-GDM male fetus revealed differently methylation genes enriched in obesity and diabetic pathogenesis. Methylation validation of targeted gene Fyn showed consistent hypo-methylation status in F1 PGCs, F1 fetal testis, sperm of F1/N-GDM mice, and somatic cells of F2-GDM male mice. While fetal testis of F2-GDM mice showed no alteration in Fyn methylation. Our data indicates that intrauterine hyperglycemia exposure per se contributes to metabolic changes in F2 but not F3 generation, by altering methylation erasure in PGCs of F1 generation. PGCs of D13.5 male fetus from control pregnant mice (n=8) and GDM pregnant mice (F1-GDM, n=8). For each group, PGCs from every two pregnant mice were mixed to meet the required amount for sequencing. Thus we got 4 control samples and 4 GDM samples for RRBS.