Mild Gestational Hyperglycemia in Rat Induces Fetal Overgrowth and Modulates Placental Growth Factors and Nutrient Transporters Expression

<div><p>Mild gestational hyperglycemia is often associated with fetal overgrowth that can predispose the offspring to metabolic diseases later in life. We hypothesized that unfavorable intrauterine environment may compromise the development of placenta and contribute to fetal overgrowth. Therefore, we developed a rat model and investigated the effects of maternal dysglycemia on fetal growth and placental gene expression. Female rats were treated with single injection of nicotinamide plus streptozotocin (N-STZ) 1-week before mating and were studied at gestational day 21. N-STZ pregnant females displayed impaired glucose tolerance that is associated with a lower insulin secretion. Moderate hyperglycemia induced fetal overgrowth in 40% of newborns, from pregnancies with 10 to 14 pups. The incidence of macrosomia was less than 5% in the N-STZ pregnancies when the litter size exceeds 15 newborns. We found that placental mass and the labyrinthine layer were increased in macrosomic placentas. The expression of genes involved in placental development and nutrient transfer was down regulated in the N-STZ placentas of macrosomic and normosomic pups from pregnancies with 10 to 14 ones. However, we observed that lipoprotein lipase 1 (LPL1) gene expression was significantly increased in the N-STZ placentas of macrosomic pups. In pregnancies with 15 pups or more, the expression of IGFs and glucose transporter genes was also modulated in the control placentas with no additional effect in the N-STZ ones. These data suggest that placental gene expression is modulated by gestational conditions that might disrupt the fetal growth. We described here a new model of maternal glucose intolerance that results in fetal overgrowth. We proposed that over-expression of LPL1 in the placenta may contribute to the increased fetal growth in the N-STZ pregnancies. N-STZ model offers the opportunity to determinate whether these neonatal outcomes may contribute to developmental programming of metabolic diseases in adulthood.</p></div

Ingenuity pathway analysis for sexually dimorphic genes: Networks under HFD conditions (M HFD vs F HFD).

a<p>Networks with scores ≥25 are indicated. ^bGenes in bold are included in our datasets.</p>f<p>Genes more expressed in females. ^mGenes more expressed in males.</p><p>Underline corresponds to genes both dimorphic under CD or HFD conditions.</p

Multipoint linkage analysis following a dominant parametric model in the French pedigree.

<p>The positions of the genetic markers are ordered from chromosome 11p15.5 to 11q12.2 (chr11∶1,820,211–59,856,421; positions given according to human genome assembly GRCh37/hg19).</p

Ingenuity pathway analysis for sexually dimorphic genes: Biological functions under CD conditions.

a<p>The first 10 biological categories of function are indicated and function annotation with a significant z-score are detailed.</p>f<p>Genes more expressed in females. ^mGenes more expressed in males.</p><p>Underline corresponds to genes both dimorphic under CD or HFD conditions.</p

Number of variants identified through the WES analysis of the four DNA samples.

a<p>This includes all identified variants (including insertion or deletion) that reach the quality threshold and with depth of coverage ≥8×; <b><i>Novel</i></b> means not present in the public database dbSNP130; <b><i>Indel</i></b>, insertion or deletion.</p

Ingenuity pathway analysis for gene responding to HFD: Networks in female.

a<p>Networks with scores ≥25 are indicated. ^bGenes in bold are included in our datasets.</p>u<p>Upregulated genes. ^dDownregulated genes.</p><p>Underline corresponds to genes deregulated both in female and male placentas.</p

Ingenuity pathway analysis for gene responding to HFD: Biological functions in female.

a<p>The first 10 biological categories of function are indicated and function annotation with a significant z-score are detailed.</p>u<p>Upregulated genes. ^dDownregulated genes.</p><p>Underline corresponds to genes deregulated both in female and male placentas.</p

Western blotting with antibodies specific for H3K4me3 and H3K9me3.

<p>was used to determine the degree of lysine-specific methylation, in relationship with Kdm5c/5d (H3K4me3 demethylase) and Kmt1a/1b (H3K9 trimethylases). No sex- or diet-specific signal was observed.</p

Prevalence of FLEDR and TRAELDT in patients with SSc divided by antibody status.

a<p>adjusted standardized residual >1.96 indicates that the number of cases in that cell is significantly larger than would be expected if the null hypothesis were true (represented in bold), with a significance level of.05. An adjusted residual < −2.0 indicates that the number of cases in that cell is significantly smaller than would be expected if the null hypothesis were true (represented in italic).</p>b<p>when comparing different subgroups for FLEDR association: Ab neg/ACA pos/ATA pos/healthy controls: χ² = 48.5, p<10⁻⁸; Ab neg/healthy controls: not significant; ACA pos/healthy controls: χ² = 0.17, p = 0.9; ATA pos: χ² = 43.9, p<10⁻⁹.</p>c<p>when comparing different subgroups for TRAELDT association: Ab neg/ACA pos/ATA pos/healthy controls: χ² = 27.6, p = 0.00013; Ab neg/healthy controls: not significant; ACA pos: χ² = 7.9, p = 0.02; ATA pos/healthy controls: χ² = 14.6, p = 0.0007.</p

Pedigree of the family showing diabetes status of each member, as well as genetic status, age of diagnosis, treatment and date of birth.

<p>With regard to the genetic status, NM denotes the presence of the heterozygous <i>KCNJ11</i> p.Glu227Lys mutation and NN denotes the absence of mutation at the same locus. Circles represent female participants and squares male participants. A slash through the symbol indicates that the family member is deceased. Black symbols indicate patients with non autoimmune diabetes. The half-filled and quarter-filled symbols indicate individuals with impaired glucose tolerance and impaired fasting glucose, respectively. The black symbols with a white diagonal denote patients with type 1 diabetes. Green arrows point to members for whom the whole-exome was sequenced. <b><i>INS</i></b>, insulin; <b><i>OHA</i></b>, oral hypoglycaemic agents; <b><i>SU</i></b>, sulfonylurea.</p